WorldWideScience

Sample records for volumetric system calibrates

  1. Volumetric Three-Dimensional Display Systems

    Science.gov (United States)

    Blundell, Barry G.; Schwarz, Adam J.

    2000-03-01

    A comprehensive study of approaches to three-dimensional visualization by volumetric display systems This groundbreaking volume provides an unbiased and in-depth discussion on a broad range of volumetric three-dimensional display systems. It examines the history, development, design, and future of these displays, and considers their potential for application to key areas in which visualization plays a major role. Drawing substantially on material that was previously unpublished or available only in patent form, the authors establish the first comprehensive technical and mathematical formalization of the field, and examine a number of different volumetric architectures. System level design strategies are presented, from which proposals for the next generation of high-definition predictable volumetric systems are developed. To ensure that researchers will benefit from work already completed, they provide: * Descriptions of several recent volumetric display systems prepared from material supplied by the teams that created them * An abstract volumetric display system design paradigm * An historical summary of 90 years of development in volumetric display system technology * An assessment of the strengths and weaknesses of many of the systems proposed to date * A unified presentation of the underlying principles of volumetric display systems * A comprehensive bibliography Beautifully supplemented with 17 color plates that illustrate volumetric images and prototype displays, Volumetric Three-Dimensional Display Systems is an indispensable resource for professionals in imaging systems development, scientific visualization, medical imaging, computer graphics, aerospace, military planning, and CAD/CAE.

  2. Laser Based 3D Volumetric Display System

    Science.gov (United States)

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  3. Calibration Systems Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Tanya L.; Broocks, Bryan T.; Phillips, Mark C.

    2006-02-01

    The Calibration Systems project at Pacific Northwest National Laboratory (PNNL) is aimed towards developing and demonstrating compact Quantum Cascade (QC) laser-based calibration systems for infrared imaging systems. These on-board systems will improve the calibration technology for passive sensors, which enable stand-off detection for the proliferation or use of weapons of mass destruction, by replacing on-board blackbodies with QC laser-based systems. This alternative technology can minimize the impact on instrument size and weight while improving the quality of instruments for a variety of missions. The potential of replacing flight blackbodies is made feasible by the high output, stability, and repeatability of the QC laser spectral radiance.

  4. Measurement System & Calibration report

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    This Measurement System & Calibration report is describing DTU’s measurement system installed at a specific wind turbine. A major part of the sensors has been installed by others (see [1]) the rest of the sensors have been installed by DTU. The results of the measurements, described in this report...

  5. Mercury Calibration System

    Energy Technology Data Exchange (ETDEWEB)

    John Schabron; Eric Kalberer; Joseph Rovani; Mark Sanderson; Ryan Boysen; William Schuster

    2009-03-11

    U.S. Environmental Protection Agency (EPA) Performance Specification 12 in the Clean Air Mercury Rule (CAMR) states that a mercury CEM must be calibrated with National Institute for Standards and Technology (NIST)-traceable standards. In early 2009, a NIST traceable standard for elemental mercury CEM calibration still does not exist. Despite the vacature of CAMR by a Federal appeals court in early 2008, a NIST traceable standard is still needed for whatever regulation is implemented in the future. Thermo Fisher is a major vendor providing complete integrated mercury continuous emissions monitoring (CEM) systems to the industry. WRI is participating with EPA, EPRI, NIST, and Thermo Fisher towards the development of the criteria that will be used in the traceability protocols to be issued by EPA. An initial draft of an elemental mercury calibration traceability protocol was distributed for comment to the participating research groups and vendors on a limited basis in early May 2007. In August 2007, EPA issued an interim traceability protocol for elemental mercury calibrators. Various working drafts of the new interim traceability protocols were distributed in late 2008 and early 2009 to participants in the Mercury Standards Working Committee project. The protocols include sections on qualification and certification. The qualification section describes in general terms tests that must be conducted by the calibrator vendors to demonstrate that their calibration equipment meets the minimum requirements to be established by EPA for use in CAMR monitoring. Variables to be examined include linearity, ambient temperature, back pressure, ambient pressure, line voltage, and effects of shipping. None of the procedures were described in detail in the draft interim documents; however they describe what EPA would like to eventually develop. WRI is providing the data and results to EPA for use in developing revised experimental procedures and realistic acceptance criteria based on

  6. The Calibration Reference Data System

    Science.gov (United States)

    Greenfield, P.; Miller, T.

    2016-07-01

    We describe a software architecture and implementation for using rules to determine which calibration files are appropriate for calibrating a given observation. This new system, the Calibration Reference Data System (CRDS), replaces what had been previously used for the Hubble Space Telescope (HST) calibration pipelines, the Calibration Database System (CDBS). CRDS will be used for the James Webb Space Telescope (JWST) calibration pipelines, and is currently being used for HST calibration pipelines. CRDS can be easily generalized for use in similar applications that need a rules-based system for selecting the appropriate item for a given dataset; we give some examples of such generalizations that will likely be used for JWST. The core functionality of the Calibration Reference Data System is available under an Open Source license. CRDS is briefly contrasted with a sampling of other similar systems used at other observatories.

  7. Quantifying distortions in two-photon remote focussing images using a volumetric calibration specimen

    Directory of Open Access Journals (Sweden)

    Alexander David Corbett

    2014-10-01

    Full Text Available Remote focussing microscopy allows sharp, in-focus images to be acquired at speed from outside of the focal plane of an objective lens without any agitation of the specimen. However, without careful optical alignment, the advantages of remote focussing microscopy could be compromised by the introduction of depth-dependent scaling artefacts. To achieve an ideal alignment in a point-scanning remote focussing microscope, the lateral (XY scan mirror pair must be imaged onto the back focal plane of both the reference and imaging objectives, in a telecentric arrangement. However, for many commercial objective lenses, it can be difficult to accurately locate the position of the back focal plane. This paper investigates the impact of this limitation on the fidelity of three-dimensional data sets of living cardiac tissue, specifically the introduction of distortions. These distortions limit the accuracy of sarcomere measurements taken directly from raw volumetric data. The origin of the distortion is first identified through simulation of a remote focussing microscope. Using a novel three-dimensional calibration specimen it was then possible to quantify experimentally the size of the distortion as a function of objective misalignment. Finally, by first approximating and then compensating the distortion in imaging data from whole heart rodent studies, the variance of sarcomere length measurements was reduced by almost 50%.

  8. Volumetric flow rate comparisons for water and product on pasteurization systems.

    Science.gov (United States)

    Schlesser, J E; Stroup, W H; McKinstry, J A

    1994-04-01

    A flow calibration tube system was assembled to determine the volumetric flow rates for water and various dairy products through a holding tube, using three different flow promotion methods. With the homogenizer, the volumetric flow rates of water and reconstituted skim milk were within 1.5% of each other. With the positive displacement pump, the flow rate for reconstituted skim milk increased compared with that for water as the pressure increased or temperature decreased. The largest increase in flow rate was at 310-kPa gauge and 20 degrees C. On a magnetic flow meter system, the volumetric flow rates of water and reconstituted skim milk were within .5% of the flow rate measured from the volume collected in a calibrated tank. The flow rate of whole milk was similar to that of skim milk on the three flow promoters evaluated. Ice milk mix increased the flow rate of the positive displacement pump, but not the homogenizer and magnetic flow meter system.

  9. Calibrating System for Vacuum Gauges

    Institute of Scientific and Technical Information of China (English)

    MengJun; YangXiaotian; HaoBinggan; HouShengjun; HuZhenjun

    2003-01-01

    In order to measure the vacuum degree, a lot of vacuum gauges will be used in CSR vacuum system. We bought several types of vacuum gauges. We know that different typos of vacuum gauges or even one type of vacuum gauges have different measure results in same condition, so they must be calibrated. But it seems impossible for us to send so many gauges to the calibrating station outside because of the high price. So the best choice is to build a second class calibrating station for vacuum gauges by ourselves (Fig.l).

  10. The KLOE Online Calibration System

    Institute of Scientific and Technical Information of China (English)

    E.Pasqualucci

    2001-01-01

    Based on all the features of the KLOE online software,the online calibration system performs current calibration quality checking in real time and starts automatically new calibration procedures when needed.Acalibration manager process controls the system,implementing the interface to the online system,receiving information from the run control and translating its state transitions to a separate state machine.It acts as a " calibration run controller"and performs failure recovery when requested by a set of process checkers.The core of the system is a multi-threaded OO histogram server that receives histogramming commands by remote processes and operates on local ROOT histograms.A client library and C,fortran and C++ application interface libraries allow the user to connect and define his own histogram or read histograms owned by others using an bool-like interface.Several calibration processes running in parallel in a destributed,multiplatform environment can fill the same histograms,allowing fast external information check.A monitor thread allow remote browsing for visual inspection,Pre-filtered data are read in nonprivileged spy mode from the data acquisition system via the Kloe Integrated Dataflow,privileged spy mode from the data acquisiton system via the Kole Integrated Dataflow.The main characteristics of the system are presented.

  11. Measurement System and Calibration report

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    This Measurement System & Calibration report is describing DTU’s measurement system installed at a specific wind turbine. A major part of the sensors has been installed by others (see [1]) the rest of the sensors have been installed by DTU. The results of the measurements, described in this report...

  12. Measurement System and Calibration report

    DEFF Research Database (Denmark)

    Gómez Arranz, Paula; Villanueva, Héctor

    This Measurement System & Calibration report is describing DTU’s measurement system installed at a specific wind turbine. A major part of the sensors has been installed by others (see [1]) the rest of the sensors have been installed by DTU. The results of the measurements, described in this repor...

  13. Volumetric 3D Display System with Static Screen

    Science.gov (United States)

    Geng, Jason

    2011-01-01

    Current display technology has relied on flat, 2D screens that cannot truly convey the third dimension of visual information: depth. In contrast to conventional visualization that is primarily based on 2D flat screens, the volumetric 3D display possesses a true 3D display volume, and places physically each 3D voxel in displayed 3D images at the true 3D (x,y,z) spatial position. Each voxel, analogous to a pixel in a 2D image, emits light from that position to form a real 3D image in the eyes of the viewers. Such true volumetric 3D display technology provides both physiological (accommodation, convergence, binocular disparity, and motion parallax) and psychological (image size, linear perspective, shading, brightness, etc.) depth cues to human visual systems to help in the perception of 3D objects. In a volumetric 3D display, viewers can watch the displayed 3D images from a completely 360 view without using any special eyewear. The volumetric 3D display techniques may lead to a quantum leap in information display technology and can dramatically change the ways humans interact with computers, which can lead to significant improvements in the efficiency of learning and knowledge management processes. Within a block of glass, a large amount of tiny dots of voxels are created by using a recently available machining technique called laser subsurface engraving (LSE). The LSE is able to produce tiny physical crack points (as small as 0.05 mm in diameter) at any (x,y,z) location within the cube of transparent material. The crack dots, when illuminated by a light source, scatter the light around and form visible voxels within the 3D volume. The locations of these tiny voxels are strategically determined such that each can be illuminated by a light ray from a high-resolution digital mirror device (DMD) light engine. The distribution of these voxels occupies the full display volume within the static 3D glass screen. This design eliminates any moving screen seen in previous

  14. MTF analysis of a prototype table-top inverse-geometry volumetric CT system

    Science.gov (United States)

    Schmidt, Taly G.; Bennett, N. Robert; Mazin, Samuel R.; Star-Lack, Josh; Solomon, Edward G.; Pelc, Norbert J.

    2005-04-01

    This work investigates the modulation transfer function (MTF) of a prototype table-top inverse-geometry volumetric CT (IGCT) system. The IGCT system has been proposed to acquire sufficient volumetric data in one circular rotation using a large-area scanned source and a narrower array of fast detectors. The source and detector arrays have the same axial, or slice, extent, thus providing sufficient volumetric coverage. A prototype system has been built using a NexRay Scanning-Beam Digital X-ray system (NexRay, Inc., Los Gatos, CA) with the C-arm gantry in the horizontal position and a stage placed between the source and detector to rotate the scanned object. The resulting system has a 16-cm in-plane field of view (FOV) and 5-cm axial FOV. Two phantoms were constructed for measuring the MTF. A 76 micron tungsten wire placed axially in a plastic frame was used to measure the in-plane MTF, and the same wire slanted at 45 degrees was used to test the isotropy of the MTF. The data were calibrated for flat-field intensity and geometric misalignment and reconstructed using a modified 3D PET algorithm. For both phantoms, slices perpendicular to the wires were reconstructed. Simulations which model the IGCT system were used to verify the MTF measurement, along with analytical predictions. The measured MTF curve was similar in shape to the predicted curve with a 10% point at 20 lp/cm compared to a predicted 18 lp/cm. Future work will also study the uniformity of the MTF across the FOV and further characterize the IGCT system.

  15. Volumetric three-dimensional display system with rasterization hardware

    Science.gov (United States)

    Favalora, Gregg E.; Dorval, Rick K.; Hall, Deirdre M.; Giovinco, Michael; Napoli, Joshua

    2001-06-01

    An 8-color multiplanar volumetric display is being developed by Actuality Systems, Inc. It will be capable of utilizing an image volume greater than 90 million voxels, which we believe is the greatest utilizable voxel set of any volumetric display constructed to date. The display is designed to be used for molecular visualization, mechanical CAD, e-commerce, entertainment, and medical imaging. As such, it contains a new graphics processing architecture, novel high-performance line- drawing algorithms, and an API similar to a current standard. Three-dimensional imagery is created by projecting a series of 2-D bitmaps ('image slices') onto a diffuse screen that rotates at 600 rpm. Persistence of vision fuses the slices into a volume-filling 3-D image. A modified three-panel Texas Instruments projector provides slices at approximately 4 kHz, resulting in 8-color 3-D imagery comprised of roughly 200 radially-disposed slices which are updated at 20 Hz. Each slice has a resolution of 768 by 768 pixels, subtending 10 inches. An unusual off-axis projection scheme incorporating tilted rotating optics is used to maintain good focus across the projection screen. The display electronics includes a custom rasterization architecture which converts the user's 3- D geometry data into image slices, as well as 6 Gbits of DDR SDRAM graphics memory.

  16. 容积法体积管自动检定装置%Volumetric method volume tube automatic calibration device

    Institute of Scientific and Technical Information of China (English)

    周兵

    2014-01-01

    Using standard metal gauge, four-way commutator, PC, PLC as the main hardware, Kingview software development platform, The building Volumetric method volume tube automatic calibration device. According to the verification regulation requirements, To control the flow valve, Device automatically read standard gauge of metal volume value, The automatic temperature and pressure values collected, Automatically calculate the volume tube basic volume, standard error, repeatability, accuracy and repeatability. Realize the visual operation interface, save the test data, print calibration certificate, the notice of verification results, etc.%利用标准金属量器、四通换向器、计算机、PLC 为主要硬件,组态王软件为开发平台,构建容积法体积管自动检定装置。根据检定规程要求,控制流量阀,装置自动读取标准金属量器的容积值、自动采集温度、压力值,自动计算出体积管基本体积、标准误差、重复性、准确度、复现性。实现可视的操作界面、保存检定数据、打印检定证书、检定结果通知书等功能。

  17. Semi-automatic volumetrics system to parcellate ROI on neocortex

    Science.gov (United States)

    Tan, Ou; Ichimiya, Tetsuya; Yasuno, Fumihiko; Suhara, Tetsuya

    2002-05-01

    A template-based and semi-automatic volumetrics system--BrainVol is build to divide the any given patient brain to neo-cortical and sub-cortical regions. The standard region is given as standard ROI drawn on a standard brain volume. After normalization between the standard MR image and the patient MR image, the sub-cortical ROIs' boundary are refined based on gray matter. The neo-cortical ROIs are refined by sulcus information that is semi-automatically marked on the patient brain. Then the segmentation is applied to 4D PET image of same patient for calculation of TAC (Time Activity Curve) by co-registration between MR and PET.

  18. Systematic Geometric Error Modeling for Workspace Volumetric Calibration of a 5-axis Turbine Blade Grinding Machine

    Institute of Scientific and Technical Information of China (English)

    Abdul Wahid Khan; Chen Wuyi

    2010-01-01

    A systematic geometric model has been presented for calibration of a newly designed 5-axis turbine blade grinding machine.This machine is designed to serve a specific purpose to attain high accuracy and high efficiency grinding of turbine blades by eliminating the hand grinding process.Although its topology is RPPPR (P:prismatic;R:rotary),its design is quite distinct from the competitive machine tools.As error quantification is the only way to investigate,maintain and improve its accuracy,calibration is recommended for its performance assessment and acceptance testing.Systematic geometric error modeling technique is implemented and 52 position dependent and position independent errors are identified while considering the machine as five rigid bodies by eliminating the set-up errors ofworkpiece and cutting tool.39 of them are found to have influential errors and are accommodated for finding the resultant effect between the cutting tool and the workpiece in workspace volume.Rigid body kinematics techniques and homogenous transformation matrices are used for error synthesis.

  19. A volumetric flow sensor for automotive injection systems

    Science.gov (United States)

    Schmid, U.; Krötz, G.; Schmitt-Landsiedel, D.

    2008-04-01

    For further optimization of the automotive power train of diesel engines, advanced combustion processes require a highly flexible injection system, provided e.g. by the common rail (CR) injection technique. In the past, the feasibility to implement injection nozzle volumetric flow sensors based on the thermo-resistive measurement principle has been demonstrated up to injection pressures of 135 MPa (1350 bar). To evaluate the transient behaviour of the system-integrated flow sensors as well as an injection amount indicator used as a reference method, hydraulic simulations on the system level are performed for a CR injection system. Experimentally determined injection timings were found to be in good agreement with calculated values, especially for the novel sensing element which is directly implemented into the hydraulic system. For the first time pressure oscillations occurring after termination of the injection pulse, predicted theoretically, could be verified directly in the nozzle. In addition, the injected amount of fuel is monitored with the highest resolution ever reported in the literature.

  20. Systems and methods of eye tracking calibration

    DEFF Research Database (Denmark)

    2014-01-01

    Methods and systems to facilitate eye tracking control calibration are provided. One or more objects are displayed on a display of a device, where the one or more objects are associated with a function unrelated to a calculation of one or more calibration parameters. The one or more calibration...

  1. DECal: A Spectrophotometric Calibration System For DECam

    CERN Document Server

    Marshall, J L; DePoy, D L; Prochaska, Travis; Allen, Richard; Behm, Tyler W; Martin, Emily C; Veal, Brannon; Villanueva,, Steven; Williams, Patrick; Wise, Jason

    2013-01-01

    DECal is a new calibration system for the CTIO 4 m Blanco telescope. It is currently being installed as part of the Dark Energy Survey and will provide both broadband flat fields and narrowband (about 1 nm bandwidth) spectrophotometric calibration for the new Dark Energy Camera (DECam). Both of these systems share a new Lambertian flat field screen. The broadband flat field system uses LEDs to illuminate each photometric filter. The spectrophotometric calibration system consists of a monochromator-based tunable light source that is projected onto the flat field screen using a custom line-to-spot fiber bundle and an engineered diffuser. Several calibrated photodiodes positioned along the beam monitor the telescope throughput as a function of wavelength. This system will measure the wavelength-dependent instrumental response function of the total telescope+instrument system in the range 300 < lambda < 1100nm. The spectrophotometric calibration will be performed regularly (roughly once per month) to determ...

  2. FY2008 Calibration Systems Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, Bret D.; Myers, Tanya L.; Broocks, Bryan T.

    2009-01-01

    The Calibrations project has been exploring alternative technologies for calibration of passive sensors in the infrared (IR) spectral region. In particular, we have investigated using quantum cascade lasers (QCLs) because these devices offer several advantages over conventional blackbodies such as reductions in size and weight while providing a spectral source in the IR with high output power. These devices can provide a rapid, multi-level radiance scheme to fit any nonlinear behavior as well as a spectral calibration that includes the fore-optics, which is currently not available for on-board calibration systems.

  3. Measurement System and Calibration report

    DEFF Research Database (Denmark)

    Vesth, Allan; Kock, Carsten Weber

    The report describes power curve measurements carried out on a given wind turbine. The measurements are carried out in accordance to Ref. [1]. A site calibration has been carried out; see Ref. [2], and the measured flow correction factors for different wind directions are used in the present...

  4. Automated system for the calibration of magnetometers

    DEFF Research Database (Denmark)

    Petrucha, Vojtech; Kaspar, Petr; Ripka, Pavel

    2009-01-01

    A completely nonmagnetic calibration platform has been developed and constructed at DTU Space (Technical University of Denmark). It is intended for on-site scalar calibration of high-precise fluxgate magnetometers. An enhanced version of the same platform is being built at the Czech Technical Uni...... through custom-made optical incremental sensors. The system is controlled by a microcontroller, which executes commands from a computer. The properties of the system as well as calibration and measurement results will be presented. ©2009 American Institute of Physics...

  5. Colorimetric calibration of coupled infrared simulation system

    Science.gov (United States)

    Zhang, Ying; Fei, Jindong; Gao, Yang; Du, Jian

    2015-10-01

    In order to test 2-color infrared sensors, a coupled infrared simulation system can generate radiometric outputs with wavelengths that range from less than 3 microns to more than 12 microns. There are two channels in the coupled simulation system, optically combined by a diachronic beam combiner. Each channel has an infrared blackbody, a filter, a diaphragm, and diaphragm-motors. The system is projected to the sensor under testing by a collimator. This makes it difficult to calibrate the system with only one-band thermal imager. Errors will be caused in the radiance levels measured by the narrow band thermal imager. This paper describes colorimetric temperature measurement techniques that have been developed to perform radiometric calibrations of these infrared simulation systems above. The calibration system consists of two infrared thermal imagers; one is operated at the wavelength range of MW-IR, and the other at the range of LW-IR.

  6. ATLAS Tile calorimeter calibration and monitoring systems

    CERN Document Server

    Cortes-Gonzalez, Arely; The ATLAS collaboration

    2017-01-01

    The ATLAS Tile Calorimeter is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes, located in the outer part of the calorimeter. The readout is segmented into about 5000 cells (longitudinally and transversally), each of them being read out by two photomultiplier in parallel. To calibrate and monitor the stability and performance of each part of the readout chain during the data taking, a set of calibration systems is used. The calibration system comprises Cesium radioactive sources, laser, charge injection elements and an integrator based readout system. Combined information from all systems allows to monitor and equalise the calorimeter r...

  7. Volumetric Virtual Environments

    Institute of Scientific and Technical Information of China (English)

    HE Taosong

    2000-01-01

    Driven by fast development of both virtual reality and volume visualization, we discuss some critical techniques towards building a volumetric VR system, specifically the modeling, rendering, and manipulations of a volumetric scene.Techniques such as voxel-based object simplification, accelerated volume rendering,fast stereo volume rendering, and volumetric "collision detection" are introduced and improved, with the idea of demonstrating the possibilities and potential benefits of incorporating volumetric models into VR systems.

  8. Heliostat kinematic system calibration using uncalibrated cameras

    Science.gov (United States)

    Burisch, Michael; Gomez, Luis; Olasolo, David; Villasante, Cristobal

    2017-06-01

    The efficiency of the solar field greatly depends on the ability of the heliostats to precisely reflect solar radiation onto a central receiver. To control the heliostats with such a precision accurate knowledge of the motion of each of them modeled as a kinematic system is required. Determining the parameters of this system for each heliostat by a calibration system is crucial for the efficient operation of the solar field. For small sized heliostats being able to make such a calibration in a fast and automatic manner is imperative as the solar field potentially contain tens or even hundreds of thousands of them. A calibration system which can rapidly recalibrate a whole solar field would also allow reducing costs. Heliostats are generally designed to provide stability over a large period of time. Being able to relax this requirement and compensate any occurring error by adapting parameters in a model, the costs of the heliostat can be reduced. The presented method describes such an automatic calibration system using uncalibrated cameras rigidly attached to each heliostat. The cameras are used to observe targets spread out through the solar field; based on this the kinematic system of the heliostat can be estimated with high precision. A comparison of this approach to similar solutions shows the viability of the proposed solution.

  9. ATLAS Tile calorimeter calibration and monitoring systems

    CERN Document Server

    Chomont, Arthur Rene; The ATLAS collaboration

    2016-01-01

    The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes (PMTs), located on the outside of the calorimeter. The readout is segmented into about 5000 cells (longitudinally and transversally), each of them being read out by two PMTs in parallel. To calibrate and monitor the stability and performance of each part of the readout chain during the data taking, a set of calibration systems is used. The TileCal calibration system comprises Cesium radioactive sources, laser and charge injection elements and it allows to monitor and equalize the calorimeter response at each stage of the signal production, from scin...

  10. ATLAS Tile calorimeter calibration and monitoring systems

    CERN Document Server

    Chomont, Arthur Rene; The ATLAS collaboration

    2016-01-01

    The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes (PMTs), located on the outside of the calorimeter. The readout is segmented into about 5000 cells (longitudinally and transversally), each of them being read out by two PMTs in parallel. To calibrate and monitor the stability and performance of each part of the readout chain during the data taking, a set of calibration systems is used. The TileCal calibration system comprises Cesium radioactive sources, laser and charge injection elements and it allows to monitor and equalize the calorimeter response at each stage of the signal production, from scin...

  11. Volumetric Diffuse Optical Tomography for Small Animals Using a CCD-Camera-Based Imaging System

    Directory of Open Access Journals (Sweden)

    Zi-Jing Lin

    2012-01-01

    Full Text Available We report the feasibility of three-dimensional (3D volumetric diffuse optical tomography for small animal imaging by using a CCD-camera-based imaging system with a newly developed depth compensation algorithm (DCA. Our computer simulations and laboratory phantom studies have demonstrated that the combination of a CCD camera and DCA can significantly improve the accuracy in depth localization and lead to reconstruction of 3D volumetric images. This approach may present great interests for noninvasive 3D localization of an anomaly hidden in tissue, such as a tumor or a stroke lesion, for preclinical small animal models.

  12. Immune System Model Calibration by Genetic Algorithm

    NARCIS (Netherlands)

    Presbitero, A.; Krzhizhanovskaya, V.; Mancini, E.; Brands, R.; Sloot, P.

    2016-01-01

    We aim to develop a mathematical model of the human immune system for advanced individualized healthcare where medication plan is fine-tuned to fit a patient's conditions through monitored biochemical processes. One of the challenges is calibrating model parameters to satisfy existing experimental

  13. MULTIPLE ELECTRONIC CONTROL UNITS CALIBRATION SYSTEM BASED ON EXPLICIT CALIBRATION PROTOCOL AND J1939 PROTOCOL

    Institute of Scientific and Technical Information of China (English)

    YANG Shiwei; ZHU Keqing; XU Quankui; YANG Lin; ZHUO Bin

    2008-01-01

    The rising number of electronic control units (ECUs) in vehicles and the decreasing time to market have led to the need for advanced methods of calibration. A multi-ECU calibration system was developed based on the explicit calibration protocol (XCP) and J1939 communication protocol to satisfy the need of calibrating multiple ECUs simultaneously. The messages in the controller area network (CAN) are defined in the J1939 protocol. Each CAN node can get its own calibration messages and information from other ECUs, and block other messages by qualifying the CAN messages with priority, source or destination address. The data field of the calibration message is designed with the XCP , with CAN acting as the transport layer. The calibration sessions are setup with the event-triggered XCP driver in the master node and the responding XCP driver in the slave nodes. Mirroring calibration variables from ROM to RAM enables the user to calibrate ECUs online. The application example shows that the multi-ECU calibration system can calibrate multiple ECUs simultaneously, and the main program can also accomplish its calculation and send commands to the actuators in time. By the multi-ECU calibration system, the calibration effort and time can be reduced and the variables in ECU can get a better match with the variables of other ECUs.

  14. Development of a Diver-Operated Single Camera Volumetric Velocimetry System

    Science.gov (United States)

    Troutman, Valerie; Dabiri, John

    2016-11-01

    The capabilities of a single camera, volumetric velocimetry system for in situ measurement in marine environments are demonstrated by imaging a well-characterized flow in a laboratory environment. This work represents the first stages in the design of a SCUBA-diver operated system to study organisms and biological processes under the natural light in the water column. This system is primarily composed of a volumetric particle tracking diagnostic to investigate fluid-animal interactions. A target domain size of a 20 cm sided cube is sought as a key design feature for the capability of capturing the flow around a variety of benthic and freely swimming organisms. The integration of the particle tracking system with additional diagnostics will be discussed.

  15. Plume Measurement System (PLUMES) Calibration Experiment

    Science.gov (United States)

    1994-08-01

    Atle Lohrmann SonTek, Inc. 7940 Silverton Avenue, No. 105 San Diego, California 92126 and Craig Huhta JIMAR University of Hawaii, Honolulu, Hawaii 96822...Measurement System (PLUMES) Calibration Experiment by Age Lohrmann SonTek, Inc. 7940 Silverton Avenue, No. 105 San Diego, CA 92126 Craig Huhta JIMAR...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) &. PERFORMING ORGANIZATION SonTek, Inc., 7940 Silverton Avenue, No. 105, San Diego, CA 92126 REPORT NUMBER

  16. Computer Generated Hologram System for Wavefront Measurement System Calibration

    Science.gov (United States)

    Olczak, Gene

    2011-01-01

    Computer Generated Holograms (CGHs) have been used for some time to calibrate interferometers that require nulling optics. A typical scenario is the testing of aspheric surfaces with an interferometer placed near the paraxial center of curvature. Existing CGH technology suffers from a reduced capacity to calibrate middle and high spatial frequencies. The root cause of this shortcoming is as follows: the CGH is not placed at an image conjugate of the asphere due to limitations imposed by the geometry of the test and the allowable size of the CGH. This innovation provides a calibration system where the imaging properties in calibration can be made comparable to the test configuration. Thus, if the test is designed to have good imaging properties, then middle and high spatial frequency errors in the test system can be well calibrated. The improved imaging properties are provided by a rudimentary auxiliary optic as part of the calibration system. The auxiliary optic is simple to characterize and align to the CGH. Use of the auxiliary optic also reduces the size of the CGH required for calibration and the density of the lines required for the CGH. The resulting CGH is less expensive than the existing technology and has reduced write error and alignment error sensitivities. This CGH system is suitable for any kind of calibration using an interferometer when high spatial resolution is required. It is especially well suited for tests that include segmented optical components or large apertures.

  17. TECHNICAL BASIS DOCUMENT OF MARSSIM FIELD CALIBRATION FOR QUANTIFICATION OF CS-137 VOLUMETRICALLY CONTAMINATED SOILS IN THE BC CONTROLLED AREA USING 2 BY 2 SODIUM IODIDE DETECTORS

    Energy Technology Data Exchange (ETDEWEB)

    PAPPIN JL

    2007-10-26

    The purpose of this paper is to provide the Technical Basis and Documentation for Field Calibrations of radiation measurement equipment for use in the MARSSIM Seeping Surveys of the BC Controlled Area (BCCA). The Be Controlled Area is bounded on tt1e north by (but does not include) the BCCribs & Trenches and is bounded on the south by Army Loop Road. Parts of the BC Controlled Area are posted as a Contamination Area and the remainder is posted as a Soil Contamination Area. The area is approximately 13 square miles and divided into three zones (Zone A , Zone B. and Zone C). A map from reference 1 which shows the 3 zones is attached. The MARSSIM Scoping Surveys are intended 10 better identify the boundaries of the three zones based on the volumetric (pCi/g) contamination levels in the soil. The MARSSIM Field Calibration. reference 2. of radiation survey instrumentation will determine the Minimum Detectable Concentration (MDC) and an algorithm for converting counts to pCi/g. The instrumentation and corresponding results are not intended for occupational radiation protection decisions or for the release of property per DOE Order 5400.5.

  18. TECHNICAL BASIS DOCUMENT OF MARSSIM FIELD CALIBRATION FOR QUANTIFICATION OF CS-137 VOLUMETRICALLY CONTAMINATED SOILS IN THE BC CONTROLLED AREA USING 2 BY 2 SODIUM IODIDE DETECTORS

    Energy Technology Data Exchange (ETDEWEB)

    PAPPIN JL

    2007-10-26

    The purpose of this paper is to provide the Technical Basis and Documentation for Field Calibrations of radiation measurement equipment for use in the MARSSIM Seeping Surveys of the BC Controlled Area (BCCA). The Be Controlled Area is bounded on tt1e north by (but does not include) the BCCribs & Trenches and is bounded on the south by Army Loop Road. Parts of the BC Controlled Area are posted as a Contamination Area and the remainder is posted as a Soil Contamination Area. The area is approximately 13 square miles and divided into three zones (Zone A , Zone B. and Zone C). A map from reference 1 which shows the 3 zones is attached. The MARSSIM Scoping Surveys are intended 10 better identify the boundaries of the three zones based on the volumetric (pCi/g) contamination levels in the soil. The MARSSIM Field Calibration. reference 2. of radiation survey instrumentation will determine the Minimum Detectable Concentration (MDC) and an algorithm for converting counts to pCi/g. The instrumentation and corresponding results are not intended for occupational radiation protection decisions or for the release of property per DOE Order 5400.5.

  19. Volumetric MRI of the limbic system: anatomic determinants

    Energy Technology Data Exchange (ETDEWEB)

    Bilir, E.; Craven, W.; Hugg, J.; Gilliam, F.; Martin, R.; Faught, E.; Kuzniecky, R. [UAB Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, Birmingham, AL (United States)

    1998-03-01

    The limbic system comprises the hippocampal formation, fornix, mamillary bodies, thalamus, and other integrated structures. It is involved in complex functions including memory and emotion and in diseases such as temporal lobe epilepsy. Volume measurements of the amygdala and hippocampus have been used reliably to study patients with temporal lobe epilepsy but have not extended to other limbic structures. We performed volume measurements of hippocampus, amygdala, fornix and mamillary bodies in healthy individuals. Measurements of the amygdala, hippocampus, fornix and mamillary bodies revealed significant differences in volume between right and left sides (P < 0.001). The intraclass coefficient of variation for measurements was high for all structures except the mamillary bodies. Qualitative image assessment of the same structures revealed no asymmetries between the hemispheres. This technique can be applied to the study of disorders affecting the limbic system. (orig.) With 4 figs., 2 tabs., 23 refs.

  20. Volumetric analysis of the African elephant ventricular system.

    Science.gov (United States)

    Maskeo, Busisiwe C; Spocter, Muhammed A; Haagensen, Mark; Manger, Paul R

    2011-08-01

    This study used magnetic resonance imaging (MRI) to determine the volume of the ventricular system in the brain of three adult male African elephants (Loxodonta africana). The ventricular system of the elephant has a volume of ∼240 mL, an order of magnitude larger than that seen in the adult human. Despite this large size, allometric analysis indicates that the volume of the ventricles in the elephant is what one would expect for a mammal with an ∼5 kg brain. Interestingly, our comparison with other mammals revealed that primates appear to have small relative ventricular volumes, and that megachiropterans and microchiropterans follow different scaling rules when comparing ventricular volume to brain mass indicating separate phylogenetic histories. The current study provides context for one aspect of the elephant brain in the broader picture of mammalian brain evolution. Copyright © 2011 Wiley-Liss, Inc.

  1. Ozone measurement systems: associated instrumentation and calibration

    Directory of Open Access Journals (Sweden)

    J. Bellido

    2006-01-01

    Full Text Available The harmful effects produced by ozone have lead to a vast regulation to define and establish the quality goals of ambient air, based on common methods and criteria. The surveillance nets of atmospheric pollution are worldwide extended systems and the applied technology for the ozone measurement is nowadays quite standardized. The aim of this paper is to give a general view of the most common systems used in the ozone measurement in ambient air from a practical point of view. The used instrumentation and the usual calibration methods will be described.

  2. Calibration of a universal indicated turbulence system

    Science.gov (United States)

    Chapin, W. G.

    1977-01-01

    Theoretical and experimental work on a Universal Indicated Turbulence Meter is described. A mathematical transfer function from turbulence input to output indication was developed. A random ergodic process and a Gaussian turbulence distribution were assumed. A calibration technique based on this transfer function was developed. The computer contains a variable gain amplifier to make the system output independent of average velocity. The range over which this independence holds was determined. An optimum dynamic response was obtained for the tubulation between the system pitot tube and pressure transducer by making dynamic response measurements for orifices of various lengths and diameters at the source end.

  3. Performance of the ATLAS Tile LaserII Calibration System

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00124895; The ATLAS collaboration

    2015-01-01

    The new laser calibration system of the ATLAS Tile hadron calorimeter is presented. The perfomances of the calibration and monitor tools internal to the laser system are given in terms of operation time stability. The use of the laser system in the normal Tile calibration procedures is also described.

  4. Calibration and Validation of Measurement System

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Riemann, Sven; Knapp, Wilfried

    The report deals with the calibration of the measuring equipment on board the Wave Dragon, Nissum Bredning prototype.......The report deals with the calibration of the measuring equipment on board the Wave Dragon, Nissum Bredning prototype....

  5. Kinect based real-time position calibration for nasal endoscopic surgical navigation system

    Science.gov (United States)

    Fan, Jingfan; Yang, Jian; Chu, Yakui; Ma, Shaodong; Wang, Yongtian

    2016-03-01

    Unanticipated, reactive motion of the patient during skull based tumor resective surgery is the source of the consequence that the nasal endoscopic tracking system is compelled to be recalibrated. To accommodate the calibration process with patient's movement, this paper developed a Kinect based Real-time positional calibration method for nasal endoscopic surgical navigation system. In this method, a Kinect scanner was employed as the acquisition part of the point cloud volumetric reconstruction of the patient's head during surgery. Then, a convex hull based registration algorithm aligned the real-time image of the patient head with a model built upon the CT scans performed in the preoperative preparation to dynamically calibrate the tracking system if a movement was detected. Experimental results confirmed the robustness of the proposed method, presenting a total tracking error within 1 mm under the circumstance of relatively violent motions. These results point out the tracking accuracy can be retained stably and the potential to expedite the calibration of the tracking system against strong interfering conditions, demonstrating high suitability for a wide range of surgical applications.

  6. Calibration of the Hydrological Simulation Program Fortran (HSPF) model using automatic calibration and geographical information systems

    Science.gov (United States)

    Al-Abed, N. A.; Whiteley, H. R.

    2002-11-01

    Calibrating a comprehensive, multi-parameter conceptual hydrological model, such as the Hydrological Simulation Program Fortran model, is a major challenge. This paper describes calibration procedures for water-quantity parameters of the HSPF version 10·11 using the automatic-calibration parameter estimator model coupled with a geographical information system (GIS) approach for spatially averaged properties. The study area was the Grand River watershed, located in southern Ontario, Canada, between 79° 30 and 80° 57W longitude and 42° 51 and 44° 31N latitude. The drainage area is 6965 km2. Calibration efforts were directed to those model parameters that produced large changes in model response during sensitivity tests run prior to undertaking calibration. A GIS was used extensively in this study. It was first used in the watershed segmentation process. During calibration, the GIS data were used to establish realistic starting values for the surface and subsurface zone parameters LZSN, UZSN, COVER, and INFILT and physically reasonable ratios of these parameters among watersheds were preserved during calibration with the ratios based on the known properties of the subwatersheds determined using GIS. This calibration procedure produced very satisfactory results; the percentage difference between the simulated and the measured yearly discharge ranged between 4 to 16%, which is classified as good to very good calibration. The average simulated daily discharge for the watershed outlet at Brantford for the years 1981-85 was 67 m3 s-1 and the average measured discharge at Brantford was 70 m3 s-1. The coupling of a GIS with automatice calibration produced a realistic and accurate calibration for the HSPF model with much less effort and subjectivity than would be required for unassisted calibration.

  7. Design and Implementation of A Circuit Board Calibration System

    Directory of Open Access Journals (Sweden)

    Bai Hang

    2016-01-01

    Full Text Available With the development of science and technology, the traditional artificial detection methods cannot meet the requirements of modern equipment testing and calibration. Combined with the actual demand, a kind of circuit boards calibration system are put forward. It can to realize automatic testing and calibration of the circuit boards. Many functions of the calibration system such as automatic testing, self-test and monitoring are summarized. The hardware is introduced which including the industrial computer system, calibration adapter and so on. Then, development platform, the thought of program design and the structure of the software are introduced in detail. The function of automatic calibration to specific circuit boards are realized. Because the system has good commonality and easy to extend to upgrade, the development ideas and experiences can be applied to similar circuit boards automatic testing system.

  8. Structured light system calibration method with optimal fringe angle.

    Science.gov (United States)

    Li, Beiwen; Zhang, Song

    2014-11-20

    For structured light system calibration, one popular approach is to treat the projector as an inverse camera. This is usually performed by projecting horizontal and vertical sequences of patterns to establish one-to-one mapping between camera points and projector points. However, for a well-designed system, either horizontal or vertical fringe images are not sensitive to depth variation and thus yield inaccurate mapping. As a result, the calibration accuracy is jeopardized if a conventional calibration method is used. To address this limitation, this paper proposes a novel calibration method based on optimal fringe angle determination. Experiments demonstrate that our calibration approach can increase the measurement accuracy up to 38% compared to the conventional calibration method with a calibration volume of 300(H)  mm×250(W)  mm×500(D)  mm.

  9. Calibration method for a central catadioptric-perspective camera system.

    Science.gov (United States)

    He, Bingwei; Chen, Zhipeng; Li, Youfu

    2012-11-01

    A central catadioptric-perspective camera system is widely used nowadays. A critical problem is that current calibration methods cannot determine the extrinsic parameters between the central catadioptric camera and a perspective camera effectively. We present a novel calibration method for a central catadioptric-perspective camera system, in which the central catadioptric camera has a hyperbolic mirror. Two cameras are used to capture images of one calibration pattern at different spatial positions. A virtual camera is constructed at the origin of the central catadioptric camera and faced toward the calibration pattern. The transformation between the virtual camera and the calibration pattern could be computed first and the extrinsic parameters between the central catadioptric camera and the calibration pattern could be obtained. Three-dimensional reconstruction results of the calibration pattern show a high accuracy and validate the feasibility of our method.

  10. Calibration Techniques for Accurate Measurements by Underwater Camera Systems

    Directory of Open Access Journals (Sweden)

    Mark Shortis

    2015-12-01

    Full Text Available Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems.

  11. Calibration Techniques for Accurate Measurements by Underwater Camera Systems.

    Science.gov (United States)

    Shortis, Mark

    2015-12-07

    Calibration of a camera system is essential to ensure that image measurements result in accurate estimates of locations and dimensions within the object space. In the underwater environment, the calibration must implicitly or explicitly model and compensate for the refractive effects of waterproof housings and the water medium. This paper reviews the different approaches to the calibration of underwater camera systems in theoretical and practical terms. The accuracy, reliability, validation and stability of underwater camera system calibration are also discussed. Samples of results from published reports are provided to demonstrate the range of possible accuracies for the measurements produced by underwater camera systems.

  12. Mammography calibration qualities establishment in a Mo- Mo clinical system

    Science.gov (United States)

    Corrêa, E. L.; dos Santos, L. R.; Vivolo, V.; Potiens, M. P. A.

    2016-07-01

    In this study the mammography calibration qualities were established in a clinical mammography system. The objective is to provide the IPEN instruments calibration laboratory with both mammography calibration methods (using a clinical and an industrial system). The results showed a good behavior of mammography equipment, in terms of kVp, PPV and exposure time. The additional filtration of molybdenum is adequate, air-kerma rates were determined and spectra were obtained.

  13. Is your system calibrated? MRI gradient system calibration for pre-clinical, high-resolution imaging.

    Directory of Open Access Journals (Sweden)

    James O'Callaghan

    Full Text Available High-field, pre-clinical MRI systems are widely used to characterise tissue structure and volume in small animals, using high resolution imaging. Both applications rely heavily on the consistent, accurate calibration of imaging gradients, yet such calibrations are typically only performed during maintenance sessions by equipment manufacturers, and potentially with acceptance limits that are inadequate for phenotyping. To overcome this difficulty, we present a protocol for gradient calibration quality assurance testing, based on a 3D-printed, open source, structural phantom that can be customised to the dimensions of individual scanners and RF coils. In trials on a 9.4 T system, the gradient scaling errors were reduced by an order of magnitude, and displacements of greater than 100 µm, caused by gradient non-linearity, were corrected using a post-processing technique. The step-by-step protocol can be integrated into routine pre-clinical MRI quality assurance to measure and correct for these errors. We suggest that this type of quality assurance is essential for robust pre-clinical MRI experiments that rely on accurate imaging gradients, including small animal phenotyping and diffusion MR.

  14. Radioxenon detector calibration spike production and delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Foxe, Michael P.; Cameron, Ian M.; Cooper, Matthew W.; Haas, Derek A.; Hayes, James C.; Kriss, Aaron A.; Lidey, Lance S.; Mendez, Jennifer M.; Prinke, Amanda M.; Riedmann, Robin A.

    2016-03-01

    Abstract Beta-Gamma coincidence radioxenon detectors must be calibrated for each of the four-radioxenon isotopes (135Xe, 133Xe, 133mXe, and 131mXe). Without a proper calibration, there is potential for the misidentification of the amount of each isotope detected. It is important to accurately determine the amount of each radioxenon isotope, as the ratios can be used to distinguish between an anthropogenic source and a nuclear explosion. We have developed a xenon calibration system (XeCalS) that produces calibration spikes of known activity and pressure for field calibration of detectors. The activity concentrations of these calibration spikes are measured using a beta-gamma coincidence detector and a high purity germanium (HPGe) detector. We will present the results from the development and commissioning of XeCalS, along with the future plans for a portable spike implementation system.

  15. Accurate and Simple Calibration of DLP Projector Systems

    OpenAIRE

    Wilm, Jakob; Olesen, Oline Vinter; Larsen, Rasmus

    2014-01-01

    Much work has been devoted to the calibration of optical cameras, and accurate and simple methods are now available which require only a small number of calibration targets. The problem of obtaining these parameters for light projectors has not been studied as extensively and most current methods require a camera and involve feature extraction from a known projected pattern. In this work we present a novel calibration technique for DLP Projector systems based on phase shifting profilometry pr...

  16. Method for large-range structured light system calibration.

    Science.gov (United States)

    An, Yatong; Bell, Tyler; Li, Beiwen; Xu, Jing; Zhang, Song

    2016-11-20

    Structured light system calibration often requires the usage of a calibration target with a similar size as the field of view (FOV), which brings challenges to a large-range structured light system calibration since fabricating large calibration targets is difficult and expensive. This paper presents a large-range system calibration method that does not need a large calibration target. The proposed method includes two stages: (1) accurately calibrate intrinsics (i.e., focal lengths and principle points) at a near range where both the camera and projector are out of focus, and (2) calibrate the extrinsic parameters (translation and rotation) from camera to projector with the assistance of a low-accuracy, large-range three-dimensional (3D) sensor (e.g., Microsoft Kinect). We have developed a large-scale 3D shape measurement system with a FOV of 1120  mm×1900  mm×1000  mm. Experiments demonstrate our system can achieve measurement accuracy as high as 0.07 mm with a standard deviation of 0.80 mm by measuring a 304.8 mm diameter sphere. As a comparison, Kinect V2 only achieved mean error of 0.80 mm with a standard deviation of 3.41 mm for the FOV of measurement.

  17. Manual Calibration System for Daya Bay Reactor Neutrino Experiment

    Institute of Scientific and Technical Information of China (English)

    HUANG; Han-xiong; RUAN; Xi-chao; REN; Jie; LV; Yin-long; FAN; Cheng-jun; CHEN; Yan-nan; WANG; Zhao-hui; ZHOU; Zu-ying; HOU; Long; ZHANG; Jia-wen; ZHANG; Yin-hong; YU; Chao-ju; HE; Wei; ZHOU; Bin

    2012-01-01

    <正>The neutrino mixing angle θ13 with a significance of 7.7 standard deviations has been published by the Daya Bay anti-neutrino experiment collaboration in 2012. To understand the non-uniformity and the energy non-linearity of the anti-neutrino detector (AD), a calibration campaign for the AD1 with the Manual Calibration System (MCS) has been finished. The aim of this calibration plan is to deploy the calibration sources to any positions inside the Inner Acrylic Vessel (IAV), to study detail properties of AD.

  18. Internal Calibration of HJ-1-C Satellite SAR System

    Directory of Open Access Journals (Sweden)

    Yang Zhen

    2014-06-01

    Full Text Available The HJ-1-C satellite is a Synthetic Aperture Radar (SAR satellite of a small constellation for environmental and disaster monitoring. At present, it is in orbit and working well. The SAR system uses a mesh reflector antenna and centralized power amplifier, and has an internal calibration function in orbit. This study introduces the internal calibration modes and signal paths. The design and realization of the internal calibrator are discussed in detail. Finally, the internal calibration data acquired in orbit are also analyzed.

  19. Geometric calibration for a SPECT system dedicated to breast imaging

    Institute of Scientific and Technical Information of China (English)

    WU Li-Wei; WEI Long; CAO Xue-Xiang; WANG Lu; HUANG Xian-Chao; CHAI Pei; YUN Ming-Kai; ZHANG Yu-Bao; ZHANG Long; SHAN Bao-Ci

    2012-01-01

    Geometric calibration is critical to the accurate SPECT reconstruction.In this paper,a geometric calibration method was developed for a dedicated breast SPECT system with a tilted parallel beam (TPB)orbit.The acquisition geometry of the breast SPECT was firstly characterized.And then its projection model was established based on the acquisition geometry.Finally,the calibration results were obtained using a nonlinear optimization method that fitted the measured projections to the model.Monte Carlo data of the breast SPECT were used to verify the calibration method.Simulation results showed that the geometric parameters with reasonable accuracy could be obtained by the proposed method.

  20. Omnidirectional vision systems calibration, feature extraction and 3D information

    CERN Document Server

    Puig, Luis

    2013-01-01

    This work focuses on central catadioptric systems, from the early step of calibration to high-level tasks such as 3D information retrieval. The book opens with a thorough introduction to the sphere camera model, along with an analysis of the relation between this model and actual central catadioptric systems. Then, a new approach to calibrate any single-viewpoint catadioptric camera is described.  This is followed by an analysis of existing methods for calibrating central omnivision systems, and a detailed examination of hybrid two-view relations that combine images acquired with uncalibrated

  1. Ground-Based Calibration Of A Microwave Landing System

    Science.gov (United States)

    Kiriazes, John J.; Scott, Marshall M., Jr.; Willis, Alfred D.; Erdogan, Temel; Reyes, Rolando

    1996-01-01

    System of microwave instrumentation and data-processing equipment developed to enable ground-based calibration of microwave scanning-beam landing system (MSBLS) at distances of about 500 to 1,000 ft from MSBLS transmitting antenna. Ensures accuracy of MSBLS near touchdown point, without having to resort to expense and complex logistics of aircraft-based testing. Modified versions prove useful in calibrating aircraft instrument landing systems.

  2. Rapid Global Calibration Technology for Hybrid Visual Inspection System.

    Science.gov (United States)

    Liu, Tao; Yin, Shibin; Guo, Yin; Zhu, Jigui

    2017-06-19

    Vision-based methods for product quality inspection are playing an increasingly important role in modern industries for their good performance and high efficiency. A hybrid visual inspection system, which consists of an industrial robot with a flexible sensor and several stationary sensors, has been widely applied in mass production, especially in automobile manufacturing. In this paper, a rapid global calibration method for the hybrid visual inspection system is proposed. Global calibration of a flexible sensor is performed first based on the robot kinematic. Then, with the aid of the calibrated flexible sensor, stationary sensors are calibrated globally one by one based on homography. Only a standard sphere and an auxiliary target with a 2D planar pattern are applied during the system global calibration, and the calibration process can be easily re-performed during the system's periodical maintenance. An error compensation method is proposed for the hybrid inspection system, and the final accuracy of the hybrid system is evaluated with the deviation and correlation coefficient between the measured results of the hybrid system and Coordinate Measuring Machine (CMM). An accuracy verification experiment shows that deviation of over 95% of featured points are less than ±0.3 mm, and the correlation coefficients of over 85% of points are larger than 0.7.

  3. Multi-Instrument Inter-Calibration (MIIC System

    Directory of Open Access Journals (Sweden)

    Chris Currey

    2016-11-01

    Full Text Available In order to have confidence in the long-term records of atmospheric and surface properties derived from satellite measurements it is important to know the stability and accuracy of the actual radiance or reflectance measurements. Climate quality measurements require accurate calibration of space-borne instruments. Inter-calibration is the process that ties the calibration of a target instrument to a more accurate, preferably SI-traceable, reference instrument by matching measurements in time, space, wavelength, and view angles. A major challenge for any inter-calibration study is to find and acquire matched samples from within the large data volumes distributed across Earth science data centers. Typically less than 0.1% of the instrument data are required for inter-calibration analysis. Software tools and networking middleware are necessary for intelligent selection and retrieval of matched samples from multiple instruments on separate spacecraft.  This paper discusses the Multi-Instrument Inter-Calibration (MIIC system, a web-based software framework used by the Climate Absolute Radiance and Refractivity Observatory (CLARREO Pathfinder mission to simplify the data management mechanics of inter-calibration. MIIC provides three main services: (1 inter-calibration event prediction; (2 data acquisition; and (3 data analysis. The combination of event prediction and powerful server-side functions reduces the data volume required for inter-calibration studies by several orders of magnitude, dramatically reducing network bandwidth and disk storage needs. MIIC provides generic retrospective analysis services capable of sifting through large data volumes of existing instrument data. The MIIC tiered design deployed at large institutional data centers can help international organizations, such as Global Space Based Inter-Calibration System (GSICS, more efficiently acquire matched data from multiple data centers. In this paper we describe the MIIC

  4. Systematic Calibration for a Backpacked Spherical Photogrammetry Imaging System

    Science.gov (United States)

    Rau, J. Y.; Su, B. W.; Hsiao, K. W.; Jhan, J. P.

    2016-06-01

    A spherical camera can observe the environment for almost 720 degrees' field of view in one shoot, which is useful for augmented reality, environment documentation, or mobile mapping applications. This paper aims to develop a spherical photogrammetry imaging system for the purpose of 3D measurement through a backpacked mobile mapping system (MMS). The used equipment contains a Ladybug-5 spherical camera, a tactical grade positioning and orientation system (POS), i.e. SPAN-CPT, and an odometer, etc. This research aims to directly apply photogrammetric space intersection technique for 3D mapping from a spherical image stereo-pair. For this purpose, several systematic calibration procedures are required, including lens distortion calibration, relative orientation calibration, boresight calibration for direct georeferencing, and spherical image calibration. The lens distortion is serious on the ladybug-5 camera's original 6 images. Meanwhile, for spherical image mosaicking from these original 6 images, we propose the use of their relative orientation and correct their lens distortion at the same time. However, the constructed spherical image still contains systematic error, which will reduce the 3D measurement accuracy. Later for direct georeferencing purpose, we need to establish a ground control field for boresight/lever-arm calibration. Then, we can apply the calibrated parameters to obtain the exterior orientation parameters (EOPs) of all spherical images. In the end, the 3D positioning accuracy after space intersection will be evaluated, including EOPs obtained by structure from motion method.

  5. SYSTEMATIC CALIBRATION FOR A BACKPACKED SPHERICAL PHOTOGRAMMETRY IMAGING SYSTEM

    Directory of Open Access Journals (Sweden)

    J. Y. Rau

    2016-06-01

    Full Text Available A spherical camera can observe the environment for almost 720 degrees’ field of view in one shoot, which is useful for augmented reality, environment documentation, or mobile mapping applications. This paper aims to develop a spherical photogrammetry imaging system for the purpose of 3D measurement through a backpacked mobile mapping system (MMS. The used equipment contains a Ladybug-5 spherical camera, a tactical grade positioning and orientation system (POS, i.e. SPAN-CPT, and an odometer, etc. This research aims to directly apply photogrammetric space intersection technique for 3D mapping from a spherical image stereo-pair. For this purpose, several systematic calibration procedures are required, including lens distortion calibration, relative orientation calibration, boresight calibration for direct georeferencing, and spherical image calibration. The lens distortion is serious on the ladybug-5 camera’s original 6 images. Meanwhile, for spherical image mosaicking from these original 6 images, we propose the use of their relative orientation and correct their lens distortion at the same time. However, the constructed spherical image still contains systematic error, which will reduce the 3D measurement accuracy. Later for direct georeferencing purpose, we need to establish a ground control field for boresight/lever-arm calibration. Then, we can apply the calibrated parameters to obtain the exterior orientation parameters (EOPs of all spherical images. In the end, the 3D positioning accuracy after space intersection will be evaluated, including EOPs obtained by structure from motion method.

  6. Rapid Global Calibration Technology for Hybrid Visual Inspection System

    Directory of Open Access Journals (Sweden)

    Tao Liu

    2017-06-01

    Full Text Available Vision-based methods for product quality inspection are playing an increasingly important role in modern industries for their good performance and high efficiency. A hybrid visual inspection system, which consists of an industrial robot with a flexible sensor and several stationary sensors, has been widely applied in mass production, especially in automobile manufacturing. In this paper, a rapid global calibration method for the hybrid visual inspection system is proposed. Global calibration of a flexible sensor is performed first based on the robot kinematic. Then, with the aid of the calibrated flexible sensor, stationary sensors are calibrated globally one by one based on homography. Only a standard sphere and an auxiliary target with a 2D planar pattern are applied during the system global calibration, and the calibration process can be easily re-performed during the system’s periodical maintenance. An error compensation method is proposed for the hybrid inspection system, and the final accuracy of the hybrid system is evaluated with the deviation and correlation coefficient between the measured results of the hybrid system and Coordinate Measuring Machine (CMM. An accuracy verification experiment shows that deviation of over 95% of featured points are less than ±0.3 mm, and the correlation coefficients of over 85% of points are larger than 0.7.

  7. Calibration of a catadioptric omnidirectional vision system with conic mirror

    Science.gov (United States)

    Marcato Junior, J.; Tommaselli, A. M. G.; Moraes, M. V. A.

    2016-03-01

    Omnidirectional vision systems that enable 360° imaging have been widely used in several research areas, including close-range photogrammetry, which allows the accurate 3D measurement of objects. To achieve accurate results in Photogrammetric applications, it is necessary to model and calibrate these systems. The major contribution of this paper relates to the rigorous geometric modeling and calibration of a catadioptric, omnidirectional vision system that is composed of a wide-angle lens camera and a conic mirror. The indirect orientation of the omnidirectional images can also be estimated using this rigorous mathematical model. When calibrating the system, which is composed of a wide-angle camera and a conic mirror, misalignment of the conical mirror axis with respect to the camera's optical axis is a critical problem that must be considered in mathematical models. The interior calibration technique developed in this paper encompasses the following steps: wide-angle camera calibration; conic mirror modeling; and estimation of the transformation parameters between the camera and conic mirror reference systems. The main advantage of the developed technique is that it does not require accurate physical alignment between the camera and conic mirror axis. The exterior orientation is based on the properties of the conic mirror reflection. Experiments were conducted with images collected from a calibration field, and the results verified that the catadioptric omnidirectional system allows for the generation of ground coordinates with high geometric quality, provided that rigorous photogrammetric processes are applied.

  8. Vision system for dial gage torque wrench calibration

    Science.gov (United States)

    Aggarwal, Neelam; Doiron, Theodore D.; Sanghera, Paramjeet S.

    1993-11-01

    In this paper, we present the development of a fast and robust vision system which, in conjunction with the Dial Gage Calibration system developed by AKO Inc., will be used by the U.S. Army in calibrating dial gage torque wrenches. The vision system detects the change in the angular position of the dial pointer in a dial gage. The angular change is proportional to the applied torque. The input to the system is a sequence of images of the torque wrench dial gage taken at different dial pointer positions. The system then reports the angular difference between the different positions. The primary components of this vision system include modules for image acquisition, linear feature extraction and angle measurements. For each of these modules, several techniques were evaluated and the most applicable one was selected. This system has numerous other applications like vision systems to read and calibrate analog instruments.

  9. Calibration of robotic drilling systems with a moving rail

    Directory of Open Access Journals (Sweden)

    Tian Wei

    2014-12-01

    Full Text Available Industrial robots are widely used in aircraft assembly systems such as robotic drilling systems. It is necessary to expand a robot’s working range with a moving rail. A method for improving the position accuracy of an automated assembly system with an industrial robot mounted on a moving rail is proposed. A multi-station method is used to control the robot in this study. The robot only works at stations which are certain positions defined on the moving rail. The calibration of the robot system is composed by the calibration of the robot and the calibration of the stations. The calibration of the robot is based on error similarity and inverse distance weighted interpolation. The calibration of the stations is based on a magnetic strip and a magnetic sensor. Validation tests were performed in this study, which showed that the accuracy of the robot system gained significant improvement using the proposed method. The absolute position errors were reduced by about 85% to less than 0.3 mm compared with the maximum nearly 2 mm before calibration.

  10. Calibration of robotic drilling systems with a moving rail

    Institute of Scientific and Technical Information of China (English)

    Tian Wei; Zeng Yuanfan; Zhou Wei; Liao Wenhe

    2014-01-01

    Industrial robots are widely used in aircraft assembly systems such as robotic drilling sys-tems. It is necessary to expand a robot’s working range with a moving rail. A method for improving the position accuracy of an automated assembly system with an industrial robot mounted on a mov-ing rail is proposed. A multi-station method is used to control the robot in this study. The robot only works at stations which are certain positions defined on the moving rail. The calibration of the robot system is composed by the calibration of the robot and the calibration of the stations. The calibration of the robot is based on error similarity and inverse distance weighted interpolation. The calibration of the stations is based on a magnetic strip and a magnetic sensor. Validation tests were performed in this study, which showed that the accuracy of the robot system gained significant improvement using the proposed method. The absolute position errors were reduced by about 85%to less than 0.3 mm compared with the maximum nearly 2 mm before calibration.

  11. Dynamic system multivariate calibration by system identification methods

    Directory of Open Access Journals (Sweden)

    Rolf Ergon

    1998-04-01

    Full Text Available In the first part of the paper, the optimal estimator for normally nonmeasured primary outputs from a linear and time invariant dynamic system is developed. The estimator is based on an underlying Kalman filter, utilizing all available information in known inputs and measured secondary outputs. Assuming sufficient experimental data, the optimal estimator can be identified by specifying an output error model in a standard prediction error identification method. It is further shown that static estimators found by the ordinary least squares method or multivariate calibration by means of principal component regression (PCR or partial least squares regression (PLSR can be seen as special cases of the optimal dynamic estimator. Finally, it is shown that dynamic system PCR and PLSR solutions can be developed as special cases of the general estimator for dynamic systems.

  12. Mammographic Breast Density Assessment Using Automated Volumetric Software and Breast Imaging Reporting and Data System (BIRADS) Categorization by Expert Radiologists.

    Science.gov (United States)

    Damases, Christine N; Brennan, Patrick C; Mello-Thoms, Claudia; McEntee, Mark F

    2016-01-01

    To investigate agreement on mammographic breast density (MD) assessment between automated volumetric software and Breast Imaging Reporting and Data System (BIRADS) categorization by expert radiologists. Forty cases of left craniocaudal and mediolateral oblique mammograms from 20 women were used. All images had their volumetric density classified using Volpara density grade (VDG) and average volumetric breast density percentage. The same images were then classified into BIRADS categories (I-IV) by 20 American Board of Radiology examiners. The results demonstrated a moderate agreement (κ = 0.537; 95% CI = 0.234-0.699) between VDG classification and radiologists' BIRADS density assessment. Interreader agreement using BIRADS also demonstrated moderate agreement (κ = 0.565; 95% CI = 0.519-0.610) ranging from 0.328 to 0.669. Radiologists' average BIRADS was lower than average VDG scores by 0.33, with their mean being 2.13, whereas the mean VDG was 2.48 (U = -3.742; P BIRADS showed a very strong positive correlation (ρ = 0.91; P BIRADS and average volumetric breast density percentage (ρ = 0.94; P BIRADS; interreader variations still exist within BIRADS. Because of the increasing importance of MD measurement in clinical management of patients, widely accepted, reproducible, and accurate measures of MD are required. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  13. The Calibration System of the HAWC Gamma-Ray Observatory

    CERN Document Server

    Solares, Hugo A Ayala; Hui, C Michelle; Lauer, Robert J; Ren, Zhixiang; Greus, Francisco Salesa; Zhou, Hao

    2015-01-01

    The HAWC collaboration has recently completed the construction of a gamma-ray observatory at an altitude of 4100 meters on the slope of the Sierra Negra volcano in the state of Puebla, Mexico. In order to achieve an optimal angular resolution, energy reconstruction, and cosmic-ray background suppression for the air showers observed by HAWC, it is crucial to obtain good timing and charge calibrations of the photosensors in the detector. The HAWC calibration is based on a laser system which is able to deliver short light pulses to all the tanks in the array. The light intensity can range over 7 orders of magnitude, broad enough to cover all the dynamic range of the PMT readout electronics. In this contribution we will present the HAWC calibration system, together with the methods used to calibrate the detector.

  14. Development of an online radiology case review system featuring interactive navigation of volumetric image datasets using advanced visualization techniques

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hyun Kyung; Kim, Boh Kyoung; Jung, Ju Hyun; Kang, Heung Sik; Lee, Kyoung Ho [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Woo, Hyun Soo [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul (Korea, Republic of); Jo, Jae Min [Dept. of Computer Science and Engineering, Seoul National University, Seoul (Korea, Republic of); Lee, Min Hee [Dept. of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of)

    2015-11-15

    To develop an online radiology case review system that allows interactive navigation of volumetric image datasets using advanced visualization techniques. Our Institutional Review Board approved the use of the patient data and waived the need for informed consent. We determined the following system requirements: volumetric navigation, accessibility, scalability, undemanding case management, trainee encouragement, and simulation of a busy practice. The system comprised a case registry server, client case review program, and commercially available cloud-based image viewing system. In the pilot test, we used 30 cases of low-dose abdomen computed tomography for the diagnosis of acute appendicitis. In each case, a trainee was required to navigate through the images and submit answers to the case questions. The trainee was then given the correct answers and key images, as well as the image dataset with annotations on the appendix. After evaluation of all cases, the system displayed the diagnostic accuracy and average review time, and the trainee was asked to reassess the failed cases. The pilot system was deployed successfully in a hands-on workshop course. We developed an online radiology case review system that allows interactive navigation of volumetric image datasets using advanced visualization techniques.

  15. Accurate and simple calibration of DLP projector systems

    Science.gov (United States)

    Wilm, Jakob; Olesen, Oline V.; Larsen, Rasmus

    2014-03-01

    Much work has been devoted to the calibration of optical cameras, and accurate and simple methods are now available which require only a small number of calibration targets. The problem of obtaining these parameters for light projectors has not been studied as extensively and most current methods require a camera and involve feature extraction from a known projected pattern. In this work we present a novel calibration technique for DLP Projector systems based on phase shifting profilometry projection onto a printed calibration target. In contrast to most current methods, the one presented here does not rely on an initial camera calibration, and so does not carry over the error into projector calibration. A radial interpolation scheme is used to convert features coordinates into projector space, thereby allowing for a very accurate procedure. This allows for highly accurate determination of parameters including lens distortion. Our implementation acquires printed planar calibration scenes in less than 1s. This makes our method both fast and convenient. We evaluate our method in terms of reprojection errors and structured light image reconstruction quality.

  16. Landsat 8 on-orbit characterization and calibration system

    Science.gov (United States)

    Micijevic, Esad; Morfitt, Ron; Choate, Michael J.

    2011-01-01

    The Landsat Data Continuity Mission (LDCM) is planning to launch the Landsat 8 satellite in December 2012, which continues an uninterrupted record of consistently calibrated globally acquired multispectral images of the Earth started in 1972. The satellite will carry two imaging sensors: the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). The OLI will provide visible, near-infrared and short-wave infrared data in nine spectral bands while the TIRS will acquire thermal infrared data in two bands. Both sensors have a pushbroom design and consequently, each has a large number of detectors to be characterized. Image and calibration data downlinked from the satellite will be processed by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center using the Landsat 8 Image Assessment System (IAS), a component of the Ground System. In addition to extracting statistics from all Earth images acquired, the IAS will process and trend results from analysis of special calibration acquisitions, such as solar diffuser, lunar, shutter, night, lamp and blackbody data, and preselected calibration sites. The trended data will be systematically processed and analyzed, and calibration and characterization parameters will be updated using both automatic and customized manual tools. This paper describes the analysis tools and the system developed to monitor and characterize on-orbit performance and calibrate the Landsat 8 sensors and image data products.

  17. Precision Spectrophotometric Calibration System for Dark Energy Instruments

    Energy Technology Data Exchange (ETDEWEB)

    Schubnell, Michael S.

    2015-06-30

    For this research we build a precision calibration system and carried out measurements to demonstrate the precision that can be achieved with a high precision spectrometric calibration system. It was shown that the system is capable of providing a complete spectrophotometric calibration at the sub-pixel level. The calibration system uses a fast, high precision monochromator that can quickly and efficiently scan over an instrument’s entire spectral range with a spectral line width of less than 0.01 nm corresponding to a fraction of a pixel on the CCD. The system was extensively evaluated in the laboratory. Our research showed that a complete spectrophotometric calibration standard for spectroscopic survey instruments such as DESI is possible. The monochromator precision and repeatability to a small fraction of the DESI spectrograph LSF was demonstrated with re-initialization on every scan and thermal drift compensation by locking to multiple external line sources. A projector system that mimics telescope aperture for point source at infinity was demonstrated.

  18. Stereo Calibration and Rectification for Omnidirectional Multi-camera Systems

    Directory of Open Access Journals (Sweden)

    Yanchang Wang

    2012-10-01

    Full Text Available Stereo vision has been studied for decades as a fundamental problem in the field of computer vision. In recent years, computer vision and image processing with a large field of view, especially using omnidirectional vision and panoramic images, has been receiving increasing attention. An important problem for stereo vision is calibration. Although various kinds of calibration methods for omnidirectional cameras are proposed, most of them are limited to calibrate catadioptric cameras or fish‐eye cameras and cannot be applied directly to multi‐camera systems. In this work, we propose an easy calibration method with closed‐form initialization and iterative optimization for omnidirectional multi‐camera systems. The method only requires image pairs of the 2D target plane in a few different views. A method based on the spherical camera model is also proposed for rectifying omnidirectional stereo pairs. Using real data captured by Ladybug3, we carry out some experiments, including stereo calibration, rectification and 3D reconstruction. Statistical analyses and comparisons of the experimental results are also presented. As the experimental results show, the calibration results are precise and the effect of rectification is promising.

  19. Calibration of a Microwave Imaging System Using a Known Scatterer

    DEFF Research Database (Denmark)

    Rubæk, Tonny; Zhurbenko, Vitaliy

    2010-01-01

    the imaging capability of the system, it is of interest to remove it. In this work, a calibration procedure capable of removing a constant offset, i.e., the leakage, from the measured signals is presented. The calibration procedure is based on a comparison between the relative change observed between...... a measurement with an empty imaging system and a measurement with a simple known object in the system, i.e., a metal cylinder, and the relative change observed between simulations of the same two situations. Assuming that the simulation software is capable of accurately modeling the imaging system, some...... relatively simple considerations on the difference between the measured and simulated results lead to an expression for the offset. Once the offset is known, this can be subtracted from the measurement of the unknown object to be investigated (the breast). The main advantage of the calibration procedure...

  20. The KamLAND Full-Volume Calibration System

    Energy Technology Data Exchange (ETDEWEB)

    KamLAND Collaboration; Berger, B. E.; Busenitz, J.; Classen, T.; Decowski, M. P.; Dwyer, D. A.; Elor, G.; Frank, A.; Freedman, S. J.; Fujikawa, B. K.; Galloway, M.; Gray, F.; Heeger, K. M.; Hsu, L.; Ichimura, K.; Kadel, R.; Keefer, G.; Lendvai, C.; McKee, D.; O' Donnell, T.; Piepke, A.; Steiner, H. M.; Syversrud, D.; Wallig, J.; Winslow, L. A.; Ebihara, T.; Enomoto, S.; Furuno, K.; Gando, Y.; Ikeda, H.; Inoue, K.; Kibe, Y.; Kishimoto, Y.; Koga, M.; Minekawa, Y.; Mitsui, T.; Nakajima, K.; Nakajima, K.; Nakamura, K.; Owada, K.; Shimizu, I.; Shimizu, Y.; Shirai, J.; Suekane, F.; Suzuki, A.; Tamae, K.; Yoshida, S.; Kozlov, A.; Murayama, H.; Grant, C.; Leonard, D. S.; Luk, K.-B.; Jillings, C.; Mauger, C.; McKeown, R. D.; Zhang, C.; Lane, C. E.; Maricic, J.; Miletic, T.; Batygov, M.; Learned, J. G.; Matsuno, S.; Pakvasa, S.; Foster, J.; Horton-Smith, G. A.; Tang, A.; Dazeley, S.; Downum, K. E.; Gratta, G.; Tolich, K.; Bugg, W.; Efremenko, Y.; Kamyshkov, Y.; Perevozchikov, O.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Piquemal, F.; Ricol, J.-S.

    2009-03-05

    We have successfully built and operated a source deployment system for the KamLAND detector. This system was used to position radioactive sources throughout the delicate 1-kton liquid scintillator volume, while meeting stringent material cleanliness, material compatibility, and safety requirements. The calibration data obtained with this device were used to fully characterize detector position and energy reconstruction biases. As a result, the uncertainty in the size of the detector fiducial volume was reduced by a factor of two. Prior to calibration with this system, the fiducial volume was the largest source of systematic uncertainty in measuring the number of antineutrinos detected by KamLAND. This paper describes the design, operation and performance of this unique calibration system.

  1. The Dark Energy Survey Data Processing and Calibration System

    CERN Document Server

    Mohr, Joseph J; Bertin, Emmanuel; Daues, Gregory E; Desai, Shantanu; Gower, Michelle; Gruendl, Robert; Hanlon, William; Kuropatkin, Nikolay; Lin, Huan; Marriner, John; Petravick, Don; Sevilla, Ignacio; Swanson, Molly; Tomashek, Todd; Tucker, Douglas; Yanny, Brian

    2012-01-01

    The Dark Energy Survey (DES) is a 5000 deg2 grizY survey reaching characteristic photometric depths of 24th magnitude (10 sigma) and enabling accurate photometry and morphology of objects ten times fainter than in SDSS. Preparations for DES have included building a dedicated 3 deg2 CCD camera (DECam), upgrading the existing CTIO Blanco 4m telescope and developing a new high performance computing (HPC) enabled data management system (DESDM). The DESDM system will be used for processing, calibrating and serving the DES data. The total data volumes are high (~2PB), and so considerable effort has gone into designing an automated processing and quality control system. Special purpose image detrending and photometric calibration codes have been developed to meet the data quality requirements, while survey astrometric calibration, coaddition and cataloging rely on new extensions of the AstrOmatic codes which now include tools for PSF modeling, PSF homogenization, PSF corrected model fitting cataloging and joint mode...

  2. Peristaltic pump-based low range pressure sensor calibration system.

    Science.gov (United States)

    Vinayakumar, K B; Naveen Kumar, G; Nayak, M M; Dinesh, N S; Rajanna, K

    2015-11-01

    Peristaltic pumps were normally used to pump liquids in several chemical and biological applications. In the present study, a peristaltic pump was used to pressurize the chamber (positive as well negative pressures) using atmospheric air. In the present paper, we discuss the development and performance study of an automatic pressurization system to calibrate low range (millibar) pressure sensors. The system includes a peristaltic pump, calibrated pressure sensor (master sensor), pressure chamber, and the control electronics. An in-house developed peristaltic pump was used to pressurize the chamber. A closed loop control system has been developed to detect and adjust the pressure leaks in the chamber. The complete system has been integrated into a portable product. The system performance has been studied for a step response and steady state errors. The system is portable, free from oil contaminants, and consumes less power compared to existing pressure calibration systems. The veracity of the system was verified by calibrating an unknown diaphragm based pressure sensor and the results obtained were satisfactory.

  3. A harvester based calibration system for cotton yield monitors

    Science.gov (United States)

    The objective of this work was to develop a system for measuring seed cotton weight on a cotton harvester to facilitate on-farm research efforts and provide information for use in semi-real-time calibration of yield monitors. The system tested in 2014 was improved from the original design developed...

  4. Calibration system of underwater robot sensor based on CID algorithm

    Science.gov (United States)

    Wang, Xiaolong; Wang, Sen; Gao, Lifu; Wu, Shan; Wei, Shuheng

    2017-06-01

    In the calibration of static characteristic of the sensor, the original measured data are usually a nonlinear distribution. Based on this situation, underwater robot sensor static calibration system is designed. The system consists of four parts: a sensor, I-V conversion with amplifying circuit, microcontroller STM32F107 and a PC. The lower computer and the upper computer communicate by USB. A kind of adaptive cyclic iterative denoising (CID) algorithm is presented for data processing. Finally the curve will be fitted with compensation processing.

  5. Calibration of Frequency Data Collection Systems Using Shortwave Radio Signals

    Science.gov (United States)

    Estler, Ron

    2000-09-01

    The atomic-clock-derived audio tones broadcast on the National Institute of Standards and Technology (NIST) shortwave station WWV are used to calibrate computer frequency data collection systems via Fast Fourier Transforms (FFT). Once calibrated, the data collection system can be used to accurately determine the audio signals used in several instructional physical chemistry laboratory experiments. This method can be applied to virtually any hardware-software configuration that allows adjustment of the apparent time scale (digitizing rate) of the recorded audio file.

  6. Calibration of NASA Turbulent Air Motion Measurement System

    Science.gov (United States)

    Barrick, John D. W.; Ritter, John A.; Watson, Catherine E.; Wynkoop, Mark W.; Quinn, John K.; Norfolk, Daniel R.

    1996-01-01

    A turbulent air motion measurement system (TAMMS) was integrated onboard the Lockheed 188 Electra airplane (designated NASA 429) based at the Wallops Flight Facility in support of the NASA role in global tropospheric research. The system provides air motion and turbulence measurements from an airborne platform which is capable of sampling tropospheric and planetary boundary-layer conditions. TAMMS consists of a gust probe with free-rotating vanes mounted on a 3.7-m epoxy-graphite composite nose boom, a high-resolution inertial navigation system (INS), and data acquisition system. A variation of the tower flyby method augmented with radar tracking was implemented for the calibration of static pressure position error and air temperature probe. Additional flight calibration maneuvers were performed remote from the tower in homogeneous atmospheric conditions. System hardware and instrumentation are described and the calibration procedures discussed. Calibration and flight results are presented to illustrate the overall ability of the system to determine the three-component ambient wind fields during straight and level flight conditions.

  7. Calibration and investigation of infrared camera systems applying blackbody radiation

    Science.gov (United States)

    Hartmann, Juergen; Fischer, Joachim

    2001-03-01

    An experimental facility is presented, which allows calibration and detailed investigation of infrared camera systems. Various blackbodies operating in the temperature range from -60 degree(s)C up to 3000 degree(s)C serve as standard radiation sources, enabling calibration of camera systems in a wide temperature and spectral range with highest accuracy. Quantitative results and precise long-term investigations, especially in detecting climatic trends, require accurate traceability to the International Temperature Scale of 1990 (ITS-90). For the used blackbodies the traceability to ITS- 90 is either realized by standard platinum resistance thermometers (in the temperature range below 962 degree(s)C) or by absolute and relative radiometry (in the temperature range above 962 degree(s)C). This traceability is fundamental for implementation of quality assurance systems and realization of different standardizations, for example according ISO 9000. For investigation of the angular and the temperature resolution our set-up enables minimum resolvable (MRTD) and minimum detectable temperature difference (MDTD) measurements in the various temperature ranges. A collimator system may be used to image the MRTD and MDTD targets to infinity. As internal calibration of infrared camera systems critically depends on the temperature of the surrounding, the calibration and investigation of the cameras is performed in a climate box, which allows a detailed controlling of the environmental parameters like humidity and temperature. Experimental results obtained for different camera systems are presented and discussed.

  8. Improving Photometric Calibration of Meteor Video Camera Systems

    Science.gov (United States)

    Ehlert, Steven; Kingery, Aaron; Cooke, William

    2016-01-01

    Current optical observations of meteors are commonly limited by systematic uncertainties in photometric calibration at the level of approximately 0.5 mag or higher. Future improvements to meteor ablation models, luminous efficiency models, or emission spectra will hinge on new camera systems and techniques that significantly reduce calibration uncertainties and can reliably perform absolute photometric measurements of meteors. In this talk we discuss the algorithms and tests that NASA's Meteoroid Environment Office (MEO) has developed to better calibrate photometric measurements for the existing All-Sky and Wide-Field video camera networks as well as for a newly deployed four-camera system for measuring meteor colors in Johnson-Cousins BV RI filters. In particular we will emphasize how the MEO has been able to address two long-standing concerns with the traditional procedure, discussed in more detail below.

  9. Flexible Calibration Method for 3D Laser Scanner System

    Institute of Scientific and Technical Information of China (English)

    杨中东; 王鹏; 李晓慧; 孙长库

    2014-01-01

    In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square (RMS) error of distance was 0.000 7 mm.

  10. Calibration technology in application of robot-laser scanning system

    Science.gov (United States)

    Ren, YongJie; Yin, ShiBin; Zhu, JiGui

    2012-11-01

    A system composed of laser sensor and 6-DOF industrial robot is proposed to obtain complete three-dimensional (3-D) information of the object surface. Suitable for the different combining ways of laser sensor and robot, a new method to calibrate the position and pose between sensor and robot is presented. By using a standard sphere with known radius as a reference tool, the rotation and translation matrices between the laser sensor and robot are computed, respectively in two steps, so that many unstable factors introduced in conventional optimization methods can be avoided. The experimental results show that the accuracy of the proposed calibration method can be achieved up to 0.062 mm. The calibration method is also implemented into the automated robot scanning system to reconstruct a car door panel.

  11. Adaptive Color Calibration Based One-Shot Structured Light System

    Directory of Open Access Journals (Sweden)

    Jie Yuan

    2012-08-01

    Full Text Available In one-shot color structured light systems, the color of stripe patterns are typically distorted with respect to color crosstalk, ambient light and the albedo of the scanned objects, leading to mismatch in the correspondence of color stripes between the projected and captured images. In this paper, an adaptive color calibration and Discrete Trend Transform algorithm are presented to achieve high-resolution 3D reconstructions. The adaptive color calibration, according to the relative albedo in RGB channels, can improve the accuracy of labeling stripe by alleviating the effect of albedo and ambient light while decoding the color. Furthermore, the Discrete Trend Transform in the M channel makes the color calibration an effective method for detecting weak stripes due to the uneven surfaces or reflectance characteristics of the scanned objects. With this approach, the presented system is suitable for scanning moving objects and generating high-resolution 3D reconstructions without the need of dark laboratory environments.

  12. Adaptive color calibration based one-shot structured light system.

    Science.gov (United States)

    Zhou, Yu; Zhao, Dongwei; Yu, Yao; Yuan, Jie; Du, Sidan

    2012-01-01

    In one-shot color structured light systems, the color of stripe patterns are typically distorted with respect to color crosstalk, ambient light and the albedo of the scanned objects, leading to mismatch in the correspondence of color stripes between the projected and captured images. In this paper, an adaptive color calibration and Discrete Trend Transform algorithm are presented to achieve high-resolution 3D reconstructions. The adaptive color calibration, according to the relative albedo in RGB channels, can improve the accuracy of labeling stripe by alleviating the effect of albedo and ambient light while decoding the color. Furthermore, the Discrete Trend Transform in the M channel makes the color calibration an effective method for detecting weak stripes due to the uneven surfaces or reflectance characteristics of the scanned objects. With this approach, the presented system is suitable for scanning moving objects and generating high-resolution 3D reconstructions without the need of dark laboratory environments.

  13. The ALICE Silicon Pixel Detector Control and Calibration Systems

    CERN Document Server

    Calì, Ivan Amos; Manzari, Vito; Stefanini, Giorgio

    2008-01-01

    The work presented in this thesis was carried out in the Silicon Pixel Detector (SPD) group of the ALICE experiment at the Large Hadron Collider (LHC). The SPD is the innermost part (two cylindrical layers of silicon pixel detec- tors) of the ALICE Inner Tracking System (ITS). During the last three years I have been strongly involved in the SPD hardware and software development, construction and commissioning. This thesis is focused on the design, development and commissioning of the SPD Control and Calibration Systems. I started this project from scratch. After a prototyping phase now a stable version of the control and calibration systems is operative. These systems allowed the detector sectors and half-barrels test, integration and commissioning as well as the SPD commissioning in the experiment. The integration of the systems with the ALICE Experiment Control System (ECS), DAQ and Trigger system has been accomplished and the SPD participated in the experimental December 2007 commissioning run. The complex...

  14. Seismic margins and calibration of piping systems

    Energy Technology Data Exchange (ETDEWEB)

    Shieh, L.C.; Tsai, N.C.; Yang, M.S.; Wong, W.L.

    1985-01-01

    The Seismic Safety Margins Research Program (SSMRP) is a US Nuclear Regulatory Commission-funded, multiyear program conducted by Lawrence Livermore National Laboratory (LLNL). Its objective is to develop a complete, fully coupled analysis procedure for estimating the risk of earthquake-induced radioactive release from a commercial nuclear power plant and to determine major contributors to the state-of-the-art seismic and systems analysis process and explicitly includes the uncertainties in such a process. The results will be used to improve seismic licensing requirements for nuclear power plants. In Phase I of SSMRP, the overall seismic risk assessment methodology was developed and assembled. The application of this methodology to the seismic PRA (Probabilistic Risk Assessment) at the Zion Nuclear Power Plant has been documented. This report documents the method deriving response factors. The response factors, which relate design calculated responses to best estimate values, were used in the seismic response determination of piping systems for a simplified seismic probablistic risk assessment. 13 references, 31 figures, 25 tables.

  15. Numerical Analysis of a Radiant Heat Flux Calibration System

    Science.gov (United States)

    Jiang, Shanjuan; Horn, Thomas J.; Dhir, V. K.

    1998-01-01

    A radiant heat flux gage calibration system exists in the Flight Loads Laboratory at NASA's Dryden Flight Research Center. This calibration system must be well understood if the heat flux gages calibrated in it are to provide useful data during radiant heating ground tests or flight tests of high speed aerospace vehicles. A part of the calibration system characterization process is to develop a numerical model of the flat plate heater element and heat flux gage, which will help identify errors due to convection, heater element erosion, and other factors. A 2-dimensional mathematical model of the gage-plate system has been developed to simulate the combined problem involving convection, radiation and mass loss by chemical reaction. A fourth order finite difference scheme is used to solve the steady state governing equations and determine the temperature distribution in the gage and plate, incident heat flux on the gage face, and flat plate erosion. Initial gage heat flux predictions from the model are found to be within 17% of experimental results.

  16. On the efficiency calibration of a drum waste assay system

    CERN Document Server

    Dinescu, L; Cazan, I L; Macrin, R; Caragheorgheopol, G; Rotarescu, G

    2002-01-01

    The efficiency calibration of a gamma spectroscopy waste assay system, constructed by IFIN-HH, was performed. The calibration technique was based on the assumption of a uniform distribution of the source activity in the drum and also a uniform sample matrix. A collimated detector (HPGe--20% relative efficiency) placed at 30 cm from the drum was used. The detection limit for sup 1 sup 3 sup 7 Cs and sup 6 sup 0 Co is approximately 45 Bq/kg for a sample of about 400 kg and a counting time of 10 min. A total measurement uncertainty of -70% to +40% was estimated.

  17. The performance of the CHEOPS on-ground calibration system

    Science.gov (United States)

    Chazelas, B.; Wildi, F. P.; Sarajlic, M.; Sordet, M.; Deline, A.

    2016-07-01

    The CHEOPS space mission will measure photometric transits of exo-planets with a precision of 20 ppm in 6 hours of integration time on a 9th magnitude star. This corresponds to a signal-to-noise ratio of 5 for a transit of an Earth-sized planet orbiting a solar-sized star. Achieving the precision goal requires precise on-ground calibration of the payload to remove its signature from the raw data while in flight. A sophisticated calibration system will inject a stimulus beam in the payload and measure its response to the variation of electrical and environmental parameters. These variations will be compiled in a correction model. At the very end of the testing phase, the CHEOPS photometric performance will be assessed on an artificial star, applying the correction model This paper addresses some original details of the CHEOPS calibration bench and its performance as measured in the lab.

  18. The Detector Calibration System for the CUORE cryogenic bolometer array

    CERN Document Server

    Cushman, J S; Davis, C J; Ejzak, L; Lenz, D; Lim, K E; Heeger, K M; Maruyama, R H; Nucciotti, A; Sangiorgio, S; Wise, T

    2016-01-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic experiment designed to search for neutrinoless double-beta decay of $^{130}$Te and other rare events. The CUORE detector consists of 988 TeO$_2$ bolometers operated underground at 10~mK in a dilution refrigerator at the Laboratori Nazionali del Gran Sasso. Candidate events are identified through a precise measurement of their energy. The absolute energy response of the detectors is established by the regular calibration of each individual bolometer using gamma sources. The close-packed configuration of the CUORE bolometer array combined with the extensive shielding surrounding the detectors requires the placement of calibration sources within the array itself. The CUORE Detector Calibration System is designed to insert radioactive sources into and remove them from the cryostat while respecting the stringent heat load, radiopurity, and operational requirements of the experiment. This paper describes the design, commissioning...

  19. Automatic Calibration and Reconstruction for Active Vision Systems

    CERN Document Server

    Zhang, Beiwei

    2012-01-01

    In this book, the design of two new planar patterns for camera calibration of intrinsic parameters is addressed and a line-based method for distortion correction is suggested. The dynamic calibration of structured light systems, which consist of a camera and a projector is also treated. Also, the 3D Euclidean reconstruction by using the image-to-world transformation is investigated. Lastly, linear calibration algorithms for the catadioptric camera are considered, and the homographic matrix and fundamental matrix are extensively studied. In these methods, analytic solutions are provided for the computational efficiency and redundancy in the data can be easily incorporated to improve reliability of the estimations. This volume will therefore prove valuable and practical tool for researchers and practioners working in image processing and computer vision and related subjects.

  20. Novel calibration system with sparse wires for CMB polarization receivers

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, O.; /KEK, Tsukuba /Chicago U., KICP; Nguyen, H.; /Fermilab; Bischoff, C.; /Chicago U., KICP /Harvard-Smithsonian Ctr. Astrophys.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

    2011-07-01

    B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

  1. The Habitable-zone Planet Finder Calibration System

    CERN Document Server

    Halverson, Samuel; Ramsey, Lawrence; Terrien, Ryan; Roy, Arpita; Schwab, Christian; Bender, Chad; Hearty, Fred; Levi, Eric; Osterman, Steve; Ycas, Gabe; Diddams, Scott

    2014-01-01

    We present the design concept of the wavelength calibration system for the Habitable-zone Planet Finder instrument (HPF), a precision radial velocity (RV) spectrograph designed to detect terrestrial-mass planets around M-dwarfs. HPF is a stabilized, fiber-fed, R$\\sim$50,000 spectrograph operating in the near-infrared (NIR) z/Y/J bands from 0.84 to 1.3 microns. For HPF to achieve 1 m s$^{-1}$ or better measurement precision, a unique calibration system, stable to several times better precision, will be needed to accurately remove instrumental effects at an unprecedented level in the NIR. The primary wavelength calibration source is a laser frequency comb (LFC), currently in development at NIST Boulder, discussed separately in these proceedings. The LFC will be supplemented by a stabilized single-mode fiber Fabry-Perot interferometer reference source and Uranium-Neon lamp. The HPF calibration system will combine several other new technologies developed by the Penn State Optical-Infrared instrumentation group to...

  2. Novel calibration system with sparse wires for CMB polarization receivers

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, O.; /KEK, Tsukuba /Chicago U., KICP; Nguyen, H.; /Fermilab; Bischoff, C.; /Chicago U., KICP /Harvard-Smithsonian Ctr. Astrophys.; Brizius, A.; Buder, I.; Kusaka, A. /Chicago U., KICP

    2011-07-01

    B-modes in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate 'simultaneously' all detectors on the large focal plane. We developed a novel calibration system that rotates a large 'sparse' grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature from the wire surface. Since the detector has a finite beam size, the observed signal is smeared according to the beam property. The resulting smeared polarized radiation has a reasonable intensity (a few Kelvin or less) compared to the sky temperature ({approx}10 K observing condition). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.

  3. Dual-channel and multifrequency radar system calibration

    Science.gov (United States)

    Stjernman, Anders; Vivekanandan, J.; Nystrom, Anders

    1995-03-01

    Uncertainty in absolute gain and crosstalk factors are the primary sources of error in dual-channel radar measurements. A full two-port calibration technique compensates for the errors introduced due to an imperfect antenna system and improves the isolation between orthogonal polarization channels as long as the observed cross section is above the equivalent system noise cross section. A novel technique for calibrating a dual-polarized network analyzer-based scatterometer system is discussed. Rigorous two-port S-parameter representation is used to describe absolute gain and crosstalk characteristics. Validity of the crosstalk correction is demonstrated by measuring the point target scattering matrix. Correction factors are obtained by measuring the S-parameters of trihedral and dihedral corner reflectors of known sizes. Results of absolute gain of the antenna system are verified using independent test target cross section measurements.

  4. Aspects of volumetric efficiency measurement for reciprocating engines

    Directory of Open Access Journals (Sweden)

    Pešić Radivoje B.

    2013-01-01

    Full Text Available The volumetric efficiency significantly influences engine output. Both design and dimensions of an intake and exhaust system have large impact on volumetric efficiency. Experimental equipment for measuring of airflow through the engine, which is placed in the intake system, may affect the results of measurements and distort the real picture of the impact of individual structural factors. This paper deals with the problems of experimental determination of intake airflow using orifice plates and the influence of orifice plate diameter on the results of the measurements. The problems of airflow measurements through a multi-process Otto/Diesel engine were analyzed. An original method for determining volumetric efficiency was developed based on in-cylinder pressure measurement during motored operation, and appropriate calibration of the experimental procedure was performed. Good correlation between the results of application of the original method for determination of volumetric efficiency and the results of theoretical model used in research of influence of the intake pipe length on volumetric efficiency was determined. [Acknowledgments. The paper is the result of the research within the project TR 35041 financed by the Ministry of Science and Technological Development of the Republic of Serbia

  5. A New Method to Calibrate Robot Visual Measurement System

    Directory of Open Access Journals (Sweden)

    Yali Wang

    2013-01-01

    Full Text Available This paper presents a new method to calibrate the robot visual measurement system. In the paper, a laser tracker is used to calibrate the robot twist angles. Each axis of the robot is moved to many positions and the positions measured by the laser tracker fit a plane. The normal vectors of the planes are the directions of the Z axes. According to the definition of the robot kinematics model parameters, the errors of the twist angles can be calculated. The joint angles zero offsets are calibrated by the constraint that the rotation relationship between the world frame and the robot base frame is relatively constant. A planar target with several parallel lines is used to obtain the pose of the camera relative to the planar target by the lines in the target plane and the vanishing line of the plane. The quantum behaved particle swarm optimization (QPSO algorithm is used to calculate the parameters. Experiments are performed and the results show that the accuracy of the robot visual measurement system is improved about 10 times after being calibrated.

  6. The detector calibration system for the CUORE cryogenic bolometer array

    Science.gov (United States)

    Cushman, Jeremy S.; Dally, Adam; Davis, Christopher J.; Ejzak, Larissa; Lenz, Daniel; Lim, Kyungeun E.; Heeger, Karsten M.; Maruyama, Reina H.; Nucciotti, Angelo; Sangiorgio, Samuele; Wise, Thomas

    2017-02-01

    The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic experiment designed to search for neutrinoless double-beta decay of 130Te and other rare events. The CUORE detector consists of 988 TeO2 bolometers operated underground at 10 mK in a dilution refrigerator at the Laboratori Nazionali del Gran Sasso. Candidate events are identified through a precise measurement of their energy. The absolute energy response of the detectors is established by the regular calibration of each individual bolometer using gamma sources. The close-packed configuration of the CUORE bolometer array combined with the extensive shielding surrounding the detectors requires the placement of calibration sources within the array itself. The CUORE Detector Calibration System is designed to insert radioactive sources into and remove them from the cryostat while respecting the stringent heat load, radiopurity, and operational requirements of the experiment. This paper describes the design, commissioning, and performance of this novel source calibration deployment system for ultra-low-temperature environments.

  7. Calibration procedure of measuring system for vehicle wheel load estimation

    Science.gov (United States)

    Kluziewicz, M.; Maniowski, M.

    2016-09-01

    The calibration procedure of wheel load measuring system is presented. Designed method allows estimation of selected wheel load components while the vehicle is in motion. Mentioned system is developed to determine friction forces between tire and road surface, basing on measured internal reaction forces in wheel suspension mechanism. Three strain gauge bridges and three-component piezoelectric load cell are responsible for internal force measurement in suspension components, two wire sensors are measuring displacements. External load is calculated via kinematic model of suspension mechanism implemented in Matlab environment. In the described calibration procedure, internal reactions are measured on a test stand while the system is loaded by a force of known direction and value.

  8. Design of a novel digital phantom for EIT system calibration.

    Science.gov (United States)

    Li, Nan; Wang, Wei; Xu, Hui

    2011-01-01

    This paper presented the design method of a novel digital phantom for electrical impedance tomography system calibration. By current sensing, voltage generating circuitry and digital processing algorithms implemented in FPGA, the digital phantom can simulate different impedances of tissues. The hardware of the digital phantom mainly consists of current sensing section, voltage generating section, electrodes switching section and a FPGA. Concerning software, the CORDIC algorithm is implemented in the FPGA to realize direct digital synthesis (DDS) technique and related algorithms. Simulation results show that the suggested system exhibits sufficient accuracy in the frequency range 10 Hz to 2 MHz. With the advantages offered by digital techniques, our approach has the potential of speed, accuracy and flexibility of the EIT system calibration process.

  9. X-ray cone beam CT system calibration

    Science.gov (United States)

    Sire, Pascal; Rizo, Philippe; Martin, M.

    1993-12-01

    Recently x-ray cone beam computed tomography (CT) has become of interest for nondestructive testing (NDT) of advanced materials. Such a technique takes advantage of the cone beam geometry, to reduce the acquisition time and increase the resolution. Performances of CT systems rely mainly on geometric precision and measurement quality. Inaccurate geometry or incorrect data produce artifacts and blurring which limit the spatial resolution. A precise geometric calibration procedure is required and some corrections must be applied to the raw attenuation data in order to obtain accurate measurements. An x-ray cone beam CT system has been developed at the LETI. This machine was designed to control small parts limited to a few centimeters, with a high spatial resolution close to 30 microns. This paper introduces the machine setup and describes the calibration computing resources involved in the system. Then, we discuss the performances on experimental data.

  10. CMR Shuffler System: Passive Mode Calibration and Certification Report

    Energy Technology Data Exchange (ETDEWEB)

    Frame, Katherine C. [Los Alamos National Laboratory; Gomez, Cipriano D. [Retired CMR-OPS: OPERATIONS; Salazar, William R. [Los Alamos National Laboratory; Mayo, Douglas R. [Los Alamos National Laboratory; Vigil, Georgiana M. [Los Alamos National Laboratory; Crooks, William J. [Los Alamos National Laboratory; Stange, Sy [Los Alamos National Laboratory

    2012-07-20

    Los Alamos National Laboratory has a number of spherical confinement vessels (CVs) remaining from tests involving nuclear materials. These vessels have an inner diameter of 6 feet with 1 to 2 inch thick steel walls. The goal of the Confinement Vessel Disposition (CVD) project is to remove debris and reduce contamination inside the vessels. As debris is removed from the vessels, material will be placed in waste drums. Far-field gamma ray assay will be used to determine when a drum is nearing a {sup 239}Pu equivalent mass of less than 200 g. The drum will then be assayed using a waste drum shuffler operated in passive mode using a neutron coincidence counting method for accountability. This report focuses on the testing and calibration of the CMR waste drum shuffler in passive mode operation. Initial testing was performed to confirm previously accepted measurement parameters. The system was then calibrated using a set of weapons grade Pu (WGPu, {sup 239}Pu > 93%) oxide standards placed inside a 55 gallon drum. The calibration data ranges from Pu mass of 0.5 g to 188.9 g. The CMR waste drum shuffler has been tested and calibrated in passive mode in preparation for safeguards accountability measurements of waste drums containing material removed from CVs for the CVD project.

  11. Online Calibration for LTE-Based Antenna Array System

    Directory of Open Access Journals (Sweden)

    Kyunghoon Kim

    2016-01-01

    Full Text Available This paper presents a novel calibration method that equalizes the impulse responses of all the Radio Frequency (RF modules of an antenna array system operating in Long-Term Evolution (LTE evolved NodeB (eNB. The proposed technique utilizes the Zadoff-Chu (Z-C sequence of the Primary Synchronization Signal (PSS and Sounding Reference Signal (SRS that are available in every LTE data frame for downlink and uplink, respectively, for estimating and compensating the differences in the impulse responses among the RF modules. The proposed calibration method is suitable for wide bandwidth signal environments of LTE because it equalizes the impulse response of each RF module, which is ultimately equivalent to compensate the phase and amplitude differences among RF modules for the entire frequency band. In addition, the proposed method is applicable while the target eNB is transmitting or receiving a data stream. From various experimental tests obtained from a test-bed implemented with 2 RF modules, it has been verified that the proposed method provides a reliable calibration for Release 10 Time Division Duplex (TDD LTE signals. Phase errors after the calibration in our test-bed have been found to be about 2.418° and 2.983° for downlink and uplink, respectively.

  12. Analysis of direct clinical consequences of MLC positional errors in volumetric-modulated arc therapy using 3D dosimetry system.

    Science.gov (United States)

    Nithiyanantham, Karthikeyan; Mani, Ganesh K; Subramani, Vikraman; Mueller, Lutz; Palaniappan, Karrthick K; Kataria, Tejinder

    2015-09-08

    In advanced, intensity-modulated external radiotherapy facility, the multileaf collimator has a decisive role in the beam modulation by creating multiple segments or dynamically varying field shapes to deliver a uniform dose distribution to the target with maximum sparing of normal tissues. The position of each MLC leaf has become more critical for intensity-modulated delivery (step-and-shoot IMRT, dynamic IMRT, and VMAT) compared to 3D CRT, where it defines only field boundaries. We analyzed the impact of the MLC positional errors on the dose distribution for volumetric-modulated arc therapy, using a 3D dosimetry system. A total of 15 VMAT cases, five each for brain, head and neck, and prostate cases, were retrospectively selected for the study. All the plans were generated in Monaco 3.0.0v TPS (Elekta Corporation, Atlanta, GA) and delivered using Elekta Synergy linear accelerator. Systematic errors of +1, +0.5, +0.3, 0, -1, -0.5, -0.3 mm were introduced in the MLC bank of the linear accelerator and the impact on the dose distribution of VMAT delivery was measured using the COMPASS 3D dosim-etry system. All the plans were created using single modulated arcs and the dose calculation was performed using a Monte Carlo algorithm in a grid size of 3 mm. The clinical endpoints D95%, D50%, D2%, and Dmax,D20%, D50% were taken for the evaluation of the target and critical organs doses, respectively. A significant dosimetric effect was found for many cases even with 0.5 mm of MLC positional errors. The average change of dose D 95% to PTV for ± 1 mm, ± 0.5 mm, and ±0.3mm was 5.15%, 2.58%, and 0.96% for brain cases; 7.19%, 3.67%, and 1.56% for head and neck cases; and 8.39%, 4.5%, and 1.86% for prostate cases, respectively. The average deviation of dose Dmax was 5.4%, 2.8%, and 0.83% for brainstem in brain cases; 8.2%, 4.4%, and 1.9% for spinal cord in H&N; and 10.8%, 6.2%, and 2.1% for rectum in prostate cases, respectively. The average changes in dose followed a linear

  13. A linear signal transmission system calibration method of wideband GPR

    Science.gov (United States)

    Wu, Bin; Zhao, Kai; Gu, Ling-jia; Cao, Qiong; Li, Xiao-feng; Zheng, Xing-ming

    2016-09-01

    In VHF pulse Ground Penetrating Radar(GPR) system, the echo pass through the antenna and transmission line circuit, then reach the GPR receiver. Thus the reflection coefficient at the receiver sampling gate interface, which is at the end of the transmission line, is different from the real reflection coefficient of the media at the antenna interface, which could cause the GPR receiving error. The pulse GPR receiver is a wideband system that can't be simply described as traditional narrowband transmission line model. Since the GPR transmission circuit is a linear system, the linear transformation method could be used to analyze the characteristic of the GPR receiving system. A GPR receiver calibration method based on transmission line theory is proposed in this paper, which analyzes the relationship between the reflection coefficients of theory calculation at antenna interface and the measuring data by network analyzer at the sampling gate interface. Then the least square method is introduced to calibrate the transfer function of the GPR receiver transmission circuit. This calibration method can be useful in media quantitative inversion by GPR. When the reflection coefficient at the sampling gate is obtained, the real reflection coefficient of the media at the antenna interface can be easily determined.

  14. Calibration of a Microwave Imaging System Using a Known Scatterer

    DEFF Research Database (Denmark)

    Rubæk, Tonny; Zhurbenko, Vitaliy

    2010-01-01

    An increasing number of operational microwave imaging systems have been presented in recent years, especially for medical imaging. This has increased the focus on the practical aspects of microwave imaging, such as the need for calibration, how to decrease measurement time, and how to minimize...... the effect of noise. At the Technical University of Denmark, a 32-channel microwave imaging system for breast cancer screening has been under development for some time. In this system, each antenna is equipped with its own transceiver module, containing amplifiers, switches, and a mixer. This design ensures...

  15. The Calibration System of the E989 Experiment at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Anastasi, Antonio [Univ. of Messina (Italy)

    2017-01-01

    The muon anomaly aµ is one of the most precise quantity known in physics experimentally and theoretically. The high level of accuracy permits to use the measurement of aµ as a test of the Standard Model comparing with the theoretical calculation. After the impressive result obtained at Brookhaven National Laboratory in 2001 with a total accuracy of 0.54 ppm, a new experiment E989 is under construction at Fermilab, motivated by the diff of aexp SM µ - aµ ~ 3σ. The purpose of the E989 experiment is a fourfold reduction of the error, with a goal of 0.14 ppm, improving both the systematic and statistical uncertainty. With the use of the Fermilab beam complex a statistic of × 21 with respect to BNL will be reached in almost 2 years of data taking improving the statistical uncertainty to 0.1 ppm. Improvement on the systematic error involves the measurement technique of ωa and ωp, the anomalous precession frequency of the muon and the Larmor precession frequency of the proton respectively. The measurement of ωp involves the magnetic field measurement and improvements on this sector related to the uniformity of the field should reduce the systematic uncertainty with respect to BNL from 170 ppb to 70 ppb. A reduction from 180 ppb to 70 ppb is also required for the measurement of ωa; new DAQ, a faster electronics and new detectors and calibration system will be implemented with respect to E821 to reach this goal. In particular the laser calibration system will reduce the systematic error due to gain fl of the photodetectors from 0.12 to 0.02 ppm. The 0.02 ppm limit on systematic requires a system with a stability of 10-4 on short time scale (700 µs) while on longer time scale the stability is at the percent level. The 10-4 stability level required is almost an order of magnitude better than the existing laser calibration system in particle physics, making the calibration system a very challenging item. In addition to the high level

  16. Improved spatial calibration for the CXRS system on EAST

    Science.gov (United States)

    Yin, X. H.; Li, Y. Y.; Fu, J.; Jiang, D.; Feng, S. Y.; Gu, Y. Q.; Cheng, Y.; Lyu, B.; Shi, Y. J.; Ye, M. Y.; Wan, B. N.

    2016-11-01

    A Charge eXchange Recombination Spectroscopy (CXRS) diagnostic system has been developed to measure profiles of ion temperature and rotation since 2014 on EAST. Several techniques have been developed to improve the spatial calibration of the CXRS diagnostic. The sightline location was obtained by measuring the coordinates of three points on each sightline using an articulated flexible coordinate measuring arm when the vessel was accessible. After vacuum pumping, the effect of pressure change in the vacuum vessel was evaluated by observing the movement of the light spot from back-illuminated sightlines on the first wall using the newly developed articulated inspection arm. In addition, the rotation of the periscope after vacuum pumping was derived by using the Doppler shift of neutral beam emission spectra without magnetic field. Combining these techniques, improved spatial calibration was implemented to provide a complete and accurate description of the EAST CXRS system. Due to the effects of the change of air pressure, a ˜0.4° periscope rotation, yielding a ˜20 mm movement of the major radius of observation positions to the lower field side, was derived. Results of Zeeman splitting of neutral beam emission spectra with magnetic field also showed good agreement with the calibration results.

  17. Calibration system for measuring the radon flux density.

    Science.gov (United States)

    Onishchenko, A; Zhukovsky, M; Bastrikov, V

    2015-06-01

    The measurement of radon flux from soil surface is the useful tool for the assessment of radon-prone areas and monitoring of radon releases from uranium mining and milling residues. The accumulation chambers with hollow headspace and chambers with activated charcoal are the most used devices for these purposes. Systematic errors of the measurements strongly depend on the geometry of the chamber and diffusion coefficient of the radon in soil. The calibration system for the attestation of devices for radon flux measurements was constructed. The calibration measurements of accumulation chambers and chambers with activated charcoal were conducted. The good agreement between the results of 2D modelling of radon flux and measurements results was observed. It was demonstrated that reliable measurements of radon flux can be obtained by chambers with activated charcoal (equivalent volume ~75 l) or by accumulation chambers with hollow headspace of ~7-10 l and volume/surface ratio (height) of >15 cm.

  18. Calibration systems and methods for the ANTARES neutrino telescope

    CERN Document Server

    Fehr, Felix

    2007-01-01

    The ANTARES neutrino telescope is currently being constructed in the Mediterranean Sea. The complete detector will consist of 12 strings, supplemented by an additional instrumentation line. Nine strings are at present deployed of which five are already connected to the shore and operating. Each string is equipped with 75 Optical Modules (OMs) housing the photomultipliers to detect the Cherenkov light induced by the charged particles produced in neutrino reactions. An accurate measurement of the Cherenkov photon arrival times as well as the positions and orientations of the OMs is required for a precise reconstruction of the direction of the detected neutrinos. For this purpose the ANTARES detector is provided with several system s to facilitate the calibration of the detector. The time calibration is performed using light pulses emitted from LED and laser devices. The positioning is done via acoustic triangulation using hydrophones. Additionally, local tilt angles and the orientations of the modules are measu...

  19. Design and development of an ultrasound calibration phantom and system

    Science.gov (United States)

    Cheng, Alexis; Ackerman, Martin K.; Chirikjian, Gregory S.; Boctor, Emad M.

    2014-03-01

    Image-guided surgery systems are often used to provide surgeons with informational support. Due to several unique advantages such as ease of use, real-time image acquisition, and no ionizing radiation, ultrasound is a common medical imaging modality used in image-guided surgery systems. To perform advanced forms of guidance with ultrasound, such as virtual image overlays or automated robotic actuation, an ultrasound calibration process must be performed. This process recovers the rigid body transformation between a tracked marker attached to the ultrasound transducer and the ultrasound image. A phantom or model with known geometry is also required. In this work, we design and test an ultrasound calibration phantom and software. The two main considerations in this work are utilizing our knowledge of ultrasound physics to design the phantom and delivering an easy to use calibration process to the user. We explore the use of a three-dimensional printer to create the phantom in its entirety without need for user assembly. We have also developed software to automatically segment the three-dimensional printed rods from the ultrasound image by leveraging knowledge about the shape and scale of the phantom. In this work, we present preliminary results from using this phantom to perform ultrasound calibration. To test the efficacy of our method, we match the projection of the points segmented from the image to the known model and calculate a sum squared difference between each point for several combinations of motion generation and filtering methods. The best performing combination of motion and filtering techniques had an error of 1.56 mm and a standard deviation of 1.02 mm.

  20. DEVELOPMENT OF POLYMER GEL SYSTEMS TO IMPROVE VOLUMETRIC SWEEP AND REDUCE PRODUCING WATER/OIL RATIOS

    Energy Technology Data Exchange (ETDEWEB)

    G. Paul Willhite; Don W. Green; Stan McCool; Min Cheng; Feiyan Chen

    2004-02-01

    The objectives of the research are to improve the effectiveness of polymer gels to increase volumetric sweep efficiency of fluid displacement processes and to reduce water production in production wells. The research is based on experimental data and conceptual and mathematical models developed from interpretation of experimental data. This report describes two types of mathematical models that were developed. One model type simulates the chemical reactions where polymer molecules are crosslinked to form a 3-dimensional network or gel. The model is based on statistical probabilities of reactions and yields molecular weights averages and distributions as functions of conversion. The second model type simulates the transport of chromium acetate, a common polymer crosslinker, through porous dolomite rock and includes the mechanisms of dolomite dissolution and chromium precipitation. The chromium transport model reasonably agreed with experimental data.

  1. The calibration system of the GERDA muon veto Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, Florian, E-mail: ritter@pit.physik.uni-tuebingen.d [Kepler Centre for Astro and Particle Physics, Universitaet Tuebingen, Tuebingen (Germany); Lubsandorzhiev, Bayarto [Kepler Centre for Astro and Particle Physics, Universitaet Tuebingen, Tuebingen (Germany); Institute for Nuclear Research of RAS, Moscow (Russian Federation); Freund, Kai; Grabmayr, Peter; Jochum, Josef; Knapp, Markus; Meierhofer, Georg [Kepler Centre for Astro and Particle Physics, Universitaet Tuebingen, Tuebingen (Germany); Shaibonov, Bator [Institute for Nuclear Research of RAS, Moscow (Russian Federation)

    2010-05-21

    The GERDA experiment searches for neutrinoless double beta decay (0{nu}{beta}{beta}). To achieve a sensitivity of 10{sup -3}counts/(keVkgy) or better within a specific region of interest (ROI), a good background identification is needed. Therefore GERDA is located in the LNGS (Laboratori Nationali del Gran Sasso) underground facility. In addition to the good rejection of cosmic muons due to the surrounding bedrocks, a dual muon veto system has to be used. For calibration and monitoring of the muon veto, two separate systems have been developed.

  2. System for Measuring Elevator Guide Rail Quality and Its Calibration

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A system for measuring the quality parameters of elevator guide rails is developed. The quality parameters the system can measure include straightness, flatness, squareness, width and height of the rail. The system consists of six parts:main guideway, auxiliary guideway, reference rail, saddle, control casing and measured rail. The guide rail to be measured is mounted on a bed.The straightness errors of surfaces are checked by five linear displacement sensors mounted on the saddle. The deviation of readings from the sensor, which is in contact with top guiding surface,gives the straightness error of the surface and height of the rail. The other four sensors are used to measure side guiding surfaces respectively and give other parameters including flatness on the surfaces, squareness, width and height of the rail. A novel calibration method is also developed to calibrate the straightness motion error of the system in horizontal and vertical directions. The deflection deformation of the measured rail is fitted by using a fourth-order polynomial. Experimental results show that the uncertainty of the system on the side surfaces after compensating the straightness motion error is less than 0.01 mm, and the uncertainty of the system on the top surface after compensating the straightness motion error and the deflection deformation of the rail is less than 0.03 mm.

  3. 21 CFR 874.3310 - Hearing aid calibrator and analysis system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hearing aid calibrator and analysis system. 874... aid calibrator and analysis system. (a) Identification. A hearing aid calibrator and analysis system... sound intensity characteristics emanating from a hearing aid, master hearing aid, group hearing aid...

  4. Calibration and Testing of Digital Zenith Camera System Components

    Science.gov (United States)

    Ulug, Rasit; Halicioglu, Kerem; Tevfik Ozludemir, M.; Albayrak, Muge; Basoglu, Burak; Deniz, Rasim

    2017-04-01

    Starting from the beginning of the new millennium, thanks to the Charged-Coupled Device (CCD) technology, fully or partly automatic zenith camera systems are designed and used in order to determine astro-geodetic deflections of the vertical components in several countries, including Germany, Switzerland, Serbia, Latvia, Poland, Austria, China and Turkey. The Digital Zenith Camera System (DZCS) of Turkey performed successful observations yet it needs to be improved in terms of automating the system and increasing observation accuracy. In order to optimize the observation time and improve the system, some modifications have been implemented. Through the modification process that started at the beginning of 2016, some DZCS components have been replaced with the new ones and some new additional components have been installed. In this presentation, the ongoing calibration and testing process of the DZCS are summarized in general. In particular, one of the tested system components is the High Resolution Tiltmeter (HRTM), which enable orthogonal orientation of DZCS to the direction of plump line, is discussed. For the calibration of these components, two tiltmeters with different accuracies (1 nrad and 0.001 mrad) were observed nearly 30 days. The data recorded under different environmental conditions were divided into hourly, daily, and weekly subsets. In addition to the effects of temperature and humidity, interoperability of two tiltmeters were also investigated. Results show that with the integration of HRTM and the other implementations, the modified DZCS provides higher accuracy for the determination of vertical deflections.

  5. Laser Tracker Calibration - Testing the Angle Measurement System -

    Energy Technology Data Exchange (ETDEWEB)

    Gassner, Georg; Ruland, Robert; /SLAC

    2008-12-05

    Physics experiments at the SLAC National Accelerator Laboratory (SLAC) usually require high accuracy positioning, e. g. 100 {micro}m over a distance of 150 m or 25 {micro}m in a 10 x 10 x 3 meter volume. Laser tracker measurement systems have become one of the most important tools for achieving these accuracies when mapping components. The accuracy of these measurements is related to the manufacturing tolerances of various individual components, the resolutions of measurement systems, the overall precision of the assembly, and how well imperfections can be modeled. As with theodolites and total stations, one can remove the effects of most assembly and calibration errors by measuring targets in both direct and reverse positions and computing the mean to obtain the result. However, this approach does not compensate for errors originating from the encoder system. In order to improve and gain a better understanding of laser tracker angle measurement tolerances we extended our laboratory's capabilities with the addition of a horizontal angle calibration test stand. This setup is based on the use of a high precision rotary table providing an angular accuracy of better than 0.2 arcsec. Presently, our setup permits only tests of the horizontal angle measurement system. A test stand for vertical angle calibration is under construction. Distance measurements (LECOCQ & FUSS, 2000) are compared to an interferometer bench for distances of up to 32 m. Together both tests provide a better understanding of the instrument and how it should be operated. The observations also provide a reasonable estimate of covariance information of the measurements according to their actual performance for network adjustments.

  6. Single-chip CMUT-on-CMOS front-end system for real-time volumetric IVUS and ICE imaging.

    Science.gov (United States)

    Gurun, Gokce; Tekes, Coskun; Zahorian, Jaime; Xu, Toby; Satir, Sarp; Karaman, Mustafa; Hasler, Jennifer; Degertekin, F Levent

    2014-02-01

    Intravascular ultrasound (IVUS) and intracardiac echography (ICE) catheters with real-time volumetric ultrasound imaging capability can provide unique benefits to many interventional procedures used in the diagnosis and treatment of coronary and structural heart diseases. Integration of capacitive micromachined ultrasonic transducer (CMUT) arrays with front-end electronics in single-chip configuration allows for implementation of such catheter probes with reduced interconnect complexity, miniaturization, and high mechanical flexibility. We implemented a single-chip forward-looking (FL) ultrasound imaging system by fabricating a 1.4-mm-diameter dual-ring CMUT array using CMUT-on-CMOS technology on a front-end IC implemented in 0.35-μm CMOS process. The dual-ring array has 56 transmit elements and 48 receive elements on two separate concentric annular rings. The IC incorporates a 25-V pulser for each transmitter and a low-noise capacitive transimpedance amplifier (TIA) for each receiver, along with digital control and smart power management. The final shape of the silicon chip is a 1.5-mm-diameter donut with a 430-μm center hole for a guide wire. The overall front-end system requires only 13 external connections and provides 4 parallel RF outputs while consuming an average power of 20 mW. We measured RF A-scans from the integrated single- chip array which show full functionality at 20.1 MHz with 43% fractional bandwidth. We also tested and demonstrated the image quality of the system on a wire phantom and an ex vivo chicken heart sample. The measured axial and lateral point resolutions are 92 μm and 251 μm, respectively. We successfully acquired volumetric imaging data from the ex vivo chicken heart at 60 frames per second without any signal averaging. These demonstrative results indicate that single-chip CMUT-on-CMOS systems have the potential to produce realtime volumetric images with image quality and speed suitable for catheter-based clinical applications.

  7. Development of a Calibration and Monitoring System for GD-1 High Pressure Common Rail Diesel Engine

    Institute of Scientific and Technical Information of China (English)

    王俊席; 杨林; 冯静; 冒晓建; 卓斌

    2004-01-01

    Based on CAN calibration protocol, a new calibration and monitoring system was developed for the GD1 high pressure common rail diesel engine. CAN driver block, monitoring program and calibration program for this system were designed respectively. The inquiry mode was used in the monitoring program and the interrupt mode was used in calibration program. The calibration program was designed in structural programming model. This system provides a reliable, accurate and quick CAN bus between ECU and PC, with baud rate up to 500Kbit/s.The implementation of the compatible and universal CAN calibration protocol makes it easy to displace the system and its function modules. It also provides friendly, compatible and flexible calibration interface, and the functions of online calibration and real-time monitoring. This system was successfully used in a GD-1 high pressure common rail diesel engine and the engine performance and exhaust emissions were significantly improved.

  8. Design of a Calibration System for Heat Flux Meters

    Science.gov (United States)

    Arpino, F.; Dell'Isola, M.; Ficco, G.; Iacomini, L.; Fernicola, V.

    2011-12-01

    Accurate heat flux measurements are needed to gain a better knowledge of the thermal performance of buildings and to evaluate the heat exchange among various parts of a building envelope. Heat flux meters (HFMs) are commonly used both in laboratory applications and in situ for measuring one-dimensional heat fluxes and, thus, estimating the thermal transmittance of material samples and existing buildings components. Building applications often requires heat flux measurements below 100 W · m-2. However, a standard reference system generating such a low heat flux is available only in a few national metrology institutes (NMIs). In this work, a numerical study aimed at designing an HFM calibration apparatus operating in the heat flux range from 5 W·m-2 to 100 W · m-2 is presented. Predictions about the metrological performance of such a calibration system were estimated by numerical modeling exploiting a commercial FEM code (COMSOL®). On the basis of the modeling results, an engineered design of such an apparatus was developed and discussed in detail. The system was designed for two different purposes: (i) for measuring the thermal conductivity of insulators and (ii) for calibrating an HFM with an absolute method (i.e., by measuring the applied power from the heater and its active cross section) or by a relative method (i.e., by measuring the temperature drop across a reference material of known thickness and thermal conductivity). The numerical investigations show that in order to minimize the uncertainty of the generated heat flux, a fine temperature control on the thermal guard is needed. The predicted standard uncertainty is within 2% at 10W·m-2 and within 0.5% at 100 W · m-2.

  9. Extrinsic Calibration for Vehicle-based Mobile Mapping System

    Directory of Open Access Journals (Sweden)

    SHI Limei

    2015-01-01

    Full Text Available Having the advantage of 360° imaging and rotation invariance, panoramic camera has gradually been used in mobile mapping systems(MMS. Calibration is an essential requirement to make sure that MMS can get high quality geo-information. This paper presents a way to address the extrinsic calibration for vehicle-based MMS composed of panoramic camera and Position and Orientation System (POS. Firstly, control points in the natural scene are set up, whose spatial coordinates are measured with high precision. Secondly, a panoramic spherical model is constructed and panoramic image can be projected to this model by means of spherical reverse transformation projection. Then, localize and select the control points in 3D spherical panoramic view but not in panoramic distorted image directly, the spherical coordinates of control points in panoramic image are gotten. After points correspondence is established, make use of direct geo-reference positioning equation and coordinate transformation, the translation and rotation parameters of panoramic camera relative to POS are computed. Experiments are conducted separately in space city calibration site located in Beijing and the Binhai New Area in Tianjin using our approach. Test results are listed as follows. When the GPS signal are of good quality, absolute positioning mean square error of a point is 10.3 cm in two-dimension plane and 16.5 cm in height direction; Otherwise, it is 35.4 cm in two-dimension plane and 54.8 cm in height direction. The max relative error of distance measurement is about 5 cm over a short distance (distance<3 km, which is not obviously affected by the GPS signal quality.

  10. Probing volumetric properties of biomolecular systems by pressure perturbation calorimetry (PPC)--the effects of hydration, cosolvents and crowding.

    Science.gov (United States)

    Suladze, Saba; Kahse, Marie; Erwin, Nelli; Tomazic, Daniel; Winter, Roland

    2015-04-01

    Pressure perturbation calorimetry (PPC) is an efficient technique to study the volumetric properties of biomolecules in solution. In PPC, the coefficient of thermal expansion of the partial volume of the biomolecule is deduced from the heat consumed or produced after small isothermal pressure-jumps. The expansion coefficient strongly depends on the interaction of the biomolecule with the solvent or cosolvent as well as on its packing and internal dynamic properties. This technique, complemented with molecular acoustics and densimetry, provides valuable insights into the basic thermodynamic properties of solvation and volume effects accompanying interactions, reactions and phase transitions of biomolecular systems. After outlining the principles of the technique, we present representative examples on protein folding, including effects of cosolvents and crowding, together with a discussion of the interpretation, and further applications. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Mars Entry Atmospheric Data System Modeling, Calibration, and Error Analysis

    Science.gov (United States)

    Karlgaard, Christopher D.; VanNorman, John; Siemers, Paul M.; Schoenenberger, Mark; Munk, Michelle M.

    2014-01-01

    The Mars Science Laboratory (MSL) Entry, Descent, and Landing Instrumentation (MEDLI)/Mars Entry Atmospheric Data System (MEADS) project installed seven pressure ports through the MSL Phenolic Impregnated Carbon Ablator (PICA) heatshield to measure heatshield surface pressures during entry. These measured surface pressures are used to generate estimates of atmospheric quantities based on modeled surface pressure distributions. In particular, the quantities to be estimated from the MEADS pressure measurements include the dynamic pressure, angle of attack, and angle of sideslip. This report describes the calibration of the pressure transducers utilized to reconstruct the atmospheric data and associated uncertainty models, pressure modeling and uncertainty analysis, and system performance results. The results indicate that the MEADS pressure measurement system hardware meets the project requirements.

  12. Calibration and Data Analysis for the KCIF Fast Magnetics System

    Energy Technology Data Exchange (ETDEWEB)

    Heeter, R. F.; Fasoli, A. F.; Ali-Arshad, A. S.; Moret, J, M.

    2000-03-01

    Alfven Eigenmodes (AEs) and other magnetohydrodynamic (MHD) phenomena have been studied at the Joint European Torus (JET) using a new 8-channel, 4 s, 1 MHz, 12-bit data acquisition system KC1F in conjunction with the JET fast Mirnov magnetic fluctuation pickup coils. The JET magnetic pickup coils were calibrated for the first time in the range 30-460 kHz using a new remote calibration technique which accounts for the presence of the first few LRC circuit resonances. A data-processing system has been developed within the MATLAB software environment to produce spectrograms of fluctuation amplitude and toroidal mode number versus frequency and time. The analysis software has been automated to allow routine overnight production of spectrogram web pages. Modes with amplitudes {delta}B/B {ge} 10{sup -8} and toroidal mode numbers |n| < 32 are now routinely detected. A pulse-characterization database has also been developed to select for the analysis of various useful subsets of the 4000+ JET discharges for which KC1F data is now available. Based on the work presented here and recent advances in data-acquisition technology, it should now be possible to obtain complete diagnostic data on the AEs.

  13. Hierarchical Bayesian Data Analysis in Radiometric SAR System Calibration: A Case Study on Transponder Calibration with RADARSAT-2 Data

    Directory of Open Access Journals (Sweden)

    Björn J. Döring

    2013-12-01

    Full Text Available A synthetic aperture radar (SAR system requires external absolute calibration so that radiometric measurements can be exploited in numerous scientific and commercial applications. Besides estimating a calibration factor, metrological standards also demand the derivation of a respective calibration uncertainty. This uncertainty is currently not systematically determined. Here for the first time it is proposed to use hierarchical modeling and Bayesian statistics as a consistent method for handling and analyzing the hierarchical data typically acquired during external calibration campaigns. Through the use of Markov chain Monte Carlo simulations, a joint posterior probability can be conveniently derived from measurement data despite the necessary grouping of data samples. The applicability of the method is demonstrated through a case study: The radar reflectivity of DLR’s new C-band Kalibri transponder is derived through a series of RADARSAT-2 acquisitions and a comparison with reference point targets (corner reflectors. The systematic derivation of calibration uncertainties is seen as an important step toward traceable radiometric calibration of synthetic aperture radars.

  14. Calibration Experiments for a Computer Vision Oyster Volume Estimation System

    Science.gov (United States)

    Chang, G. Andy; Kerns, G. Jay; Lee, D. J.; Stanek, Gary L.

    2009-01-01

    Calibration is a technique that is commonly used in science and engineering research that requires calibrating measurement tools for obtaining more accurate measurements. It is an important technique in various industries. In many situations, calibration is an application of linear regression, and is a good topic to be included when explaining and…

  15. Calibration Experiments for a Computer Vision Oyster Volume Estimation System

    Science.gov (United States)

    Chang, G. Andy; Kerns, G. Jay; Lee, D. J.; Stanek, Gary L.

    2009-01-01

    Calibration is a technique that is commonly used in science and engineering research that requires calibrating measurement tools for obtaining more accurate measurements. It is an important technique in various industries. In many situations, calibration is an application of linear regression, and is a good topic to be included when explaining and…

  16. Detection of cerebral involvement in patients with active neuropsychiatric systemic lupus erythematosus by the use of volumetric magnetization transfer imaging.

    Science.gov (United States)

    Bosma, G P; Rood, M J; Huizinga, T W; de Jong, B A; Bollen, E L; van Buchem, M A

    2000-11-01

    To determine whether volumetric magnetization transfer imaging (MTI) histogram analysis can detect abnormalities in patients with active neuropsychiatric systemic lupus erythematosus (NPSLE) and to compare the MTI findings in patients with active NPSLE, chronic NPSLE, and multiple sclerosis (MS), as well as in normal control subjects. Eight female and 1 male patient with active nonthromboembolic NPSLE (mean +/- SD age 39 +/- 9 years), 10 female patients with chronic NPSLE (age 33 +/- 11 years), 10 female patients with SLE and no history of NPSLE (non-NPSLE; age 34 +/- 11 years), 10 female patients with inactive MS (age 41 +/- 6 years), and 10 healthy control subjects (age 33 +/- 11 years) underwent MTL. Using the MTI scans, histograms were composed from which we derived a variety of parameters that quantitatively reflect the uniformity of the brain parenchyma as well as the ratio of cerebrospinal fluid to intracranial volume, which reflects atrophy. The magnetization transfer ratio (MTR) histograms in the non-NPSLE group and the healthy control group were similar, whereas those in the chronic NPSLE and MS groups were flatter. There was also flattening of the histograms in the active NPSLE group, but with a shift toward higher MTRs. Our results indicate that volumetric MTI analysis detects cerebral changes in the active phase of NPSLE. The abnormalities in the brain parenchyma of patients with chronic NPSLE produced MTI values that were the same as those in patients with inactive MS. MTI values in the active phase of NPSLE differed from those in the chronic phase, which might reflect the presence of inflammation. These preliminary results suggest that MTI might provide evidence for the presence of active NPSLE. MTI might also prove to be a valuable technique for monitoring treatment trials.

  17. A Self-Calibrating Remote Control Chemical Monitoring System

    Energy Technology Data Exchange (ETDEWEB)

    Jessica Croft

    2007-06-01

    The Susie Mine, part of the Upper Tenmile Mining Area, is located in Rimini, MT about 15 miles southwest of Helena, MT. The Upper Tenmile Creek Mining Area is an EPA Superfund site with 70 abandoned hard rock mines and several residential yards prioritized for clean up. Water from the Susie mine flows into Tenmile Creek from which the city of Helena draws part of its water supply. MSE Technology Applications in Butte, Montana was contracted by the EPA to build a treatment system for the Susie mine effluent and demonstrate a system capable of treating mine waste water in remote locations. The Idaho National Lab was contracted to design, build and demonstrate a low maintenance self-calibrating monitoring system that would monitor multiple sample points, allow remote two-way communications with the control software and allow access to the collected data through a web site. The Automated Chemical Analysis Monitoring (ACAM) system was installed in December 2006. This thesis documents the overall design of the hardware, control software and website, the data collected while MSE-TA’s system was operational, the data collected after MSE-TA’s system was shut down and suggested improvements to the existing system.

  18. Guidelines for the Calibration of Routine Dosimetry Systems for use in Radiation Processing

    DEFF Research Database (Denmark)

    Sharpe, Peter; Miller, Arne

    A set of guidelines has been developed to assist in the calibration of routine dosimetry systems for use in industrial radiation processing plants. Topics covered include the calibration of equipment, the performance of calibration irradiations and the derivation of mathematical functions...

  19. Dosimetric validation and clinical implementation of two 3D dose verification systems for quality assurance in volumetric-modulated arc therapy techniques.

    Science.gov (United States)

    Clemente-Gutiérrez, Francisco; Pérez-Vara, Consuelo

    2015-03-08

    A pretreatment quality assurance program for volumetric techniques should include redundant calculations and measurement-based verifications. The patient-specific quality assurance process must be based in clinically relevant metrics. The aim of this study was to show the commission, clinical implementation, and comparison of two systems that allow performing a 3D redundant dose calculation. In addition, one of them is capable of reconstructing the dose on patient anatomy from measurements taken with a 2D ion chamber array. Both systems were compared in terms of reference calibration data (absolute dose, output factors, percentage depth-dose curves, and profiles). Results were in good agreement for absolute dose values (discrepancies were below 0.5%) and output factors (mean differences were below 1%). Maximum mean discrepancies were located between 10 and 20 cm of depth for PDDs (-2.7%) and in the penumbra region for profiles (mean DTA of 1.5 mm). Validation of the systems was performed by comparing point-dose measurements with values obtained by the two systems for static, dynamic fields from AAPM TG-119 report, and 12 real VMAT plans for different anatomical sites (differences better than 1.2%). Comparisons between measurements taken with a 2D ion chamber array and results obtained by both systems for real VMAT plans were also performed (mean global gamma passing rates better than 87.0% and 97.9% for the 2%/2 mm and 3%/3 mm criteria). Clinical implementation of the systems was evaluated by comparing dose-volume parameters for all TG-119 tests and real VMAT plans with TPS values (mean differences were below 1%). In addition, comparisons between dose distributions calculated by TPS and those extracted by the two systems for real VMAT plans were also performed (mean global gamma passing rates better than 86.0% and 93.0% for the 2%/2 mm and 3%/ 3 mm criteria). The clinical use of both systems was successfully evaluated.

  20. Simple and accurate empirical absolute volume calibration of a multi-sensor fringe projection system

    Science.gov (United States)

    Gdeisat, Munther; Qudeisat, Mohammad; AlSa`d, Mohammed; Burton, David; Lilley, Francis; Ammous, Marwan M. M.

    2016-05-01

    This paper suggests a novel absolute empirical calibration method for a multi-sensor fringe projection system. The optical setup of the projector-camera sensor can be arbitrary. The term absolute calibration here means that the centre of the three dimensional coordinates in the resultant calibrated volume coincides with a preset centre to the three-dimensional real-world coordinate system. The use of a zero-phase fringe marking spot is proposed to increase depth calibration accuracy, where the spot centre is determined with sub-pixel accuracy. Also, a new method is proposed for transversal calibration. Depth and transversal calibration methods have been tested using both single sensor and three-sensor fringe projection systems. The standard deviation of the error produced by this system is 0.25 mm. The calibrated volume produced by this method is 400 mm×400 mm×140 mm.

  1. CRYOGENIC SYSTEM FOR PRECISE CALIBRATION OF TEMPERATURE SENSORS

    Directory of Open Access Journals (Sweden)

    A. N. Solovyev

    2016-09-01

    Full Text Available A calibration technique for cryogenic temperature sensors is proposed and implemented. The experimental setup is based on the helium cryogenerator, providing calibration of the temperature sensors of various types in wide temperature range, including cryogenic band (25-100K. A condensation thermometer with hydrogen, neon, argon and xenon as working gases is used as a reference sensor. The experimental setup was successfully used for precise (0.1K precision calibration of platinum resistive temperature detectors (Pt-100 for international nuclear physics experiments MuSun and PolFusion. The setup can also be used for calibration of temperature sensors of the other types.

  2. Study on the wavelength calibration of type III concave grating spectrometry system

    Institute of Scientific and Technical Information of China (English)

    Li Bai(白力); Ningfang Liao(廖宁放); Zhaojian Li(栗兆剑); Weiping Yang(杨卫平)

    2004-01-01

    We discuss and calibrate the spectrometry system based on concave reflection grating. The working principle, structure and parameters of the spectrometry system are introduced. For the wavelength calibration problem, three methods are put forward and discussed in detail with formulation calculation method, circular iteration method and interpolation. Interpolation is used to calibrate the concave reflection grating spectrometry system and the error is less than 1 nm. Four spectrum images that the system collected are given in this paper. The experimental results indicate that a spectrometry system can be based on concave reflection grating and be calibrated by interpolation.

  3. Flux density calibration in diffuse optical tomographic systems.

    Science.gov (United States)

    Biswas, Samir Kumar; Rajan, Kanhirodan; Vasu, Ram M

    2013-02-01

    The solution of the forward equation that models the transport of light through a highly scattering tissue material in diffuse optical tomography (DOT) using the finite element method gives flux density (Φ) at the nodal points of the mesh. The experimentally measured flux (Umeasured) on the boundary over a finite surface area in a DOT system has to be corrected to account for the system transfer functions (R) of various building blocks of the measurement system. We present two methods to compensate for the perturbations caused by R and estimate true flux density (Φ) from Umeasuredcal. In the first approach, the measurement data with a homogeneous phantom (Umeasuredhomo) is used to calibrate the measurement system. The second scheme estimates the homogeneous phantom measurement using only the measurement from a heterogeneous phantom, thereby eliminating the necessity of a homogeneous phantom. This is done by statistically averaging the data (Umeasuredhetero) and redistributing it to the corresponding detector positions. The experiments carried out on tissue mimicking phantom with single and multiple inhomogeneities, human hand, and a pork tissue phantom demonstrate the robustness of the approach.

  4. Evolution of the JPSS Ground Project Calibration and Validation System

    Science.gov (United States)

    Chander, G.; Jain, P.

    2014-12-01

    The Joint Polar Satellite System (JPSS) is the National Oceanic and Atmospheric Administration's (NOAA) next-generation operational Earth observation Program that acquires and distributes global environmental data from multiple polar-orbiting satellites. The JPSS Program plays a critical role to NOAA's mission to understand and predict changes in weather, climate, oceans, and coasts environments, which supports the nation's economy and protects lives and property. The National Aeronautics and Space Administration (NASA) is acquiring and implementing the JPSS, comprised of flight and ground systems on behalf of NOAA. The JPSS satellites are planned to fly in afternoon orbit and will provide operational continuity of satellite-based observations and products for NOAA Polar-orbiting Operational Environmental Satellites (POES) and the Suomi National Polar-orbiting Partnership (SNPP) satellite. Government Resource for Algorithm Verification, Independent Test, and Evaluation (GRAVITE) system is a NOAA system developed and deployed by JPSS Ground Project to support Calibration and Validation (Cal/Val), Algorithm Integration, Investigation, and Tuning, and Data Quality Monitoring. It is a mature, deployed system that supports SNPP mission and has been in operations since SNPP launch. This paper discusses the major re-architecture for Block 2.0 that incorporates SNPP lessons learned, architecture of the system, and demonstrates how GRAVITE has evolved as a system with increased performance. It is a robust, reliable, maintainable, scalable, and secure system that supports development, test, and production strings, replaces proprietary and custom software, uses open source software, and is compliant with NASA and NOAA standards. "[Pending NASA Goddard Applied Engineering & Technology Directorate (AETD) Approval]"

  5. A real-time camera calibration system based on OpenCV

    Science.gov (United States)

    Zhang, Hui; Wang, Hua; Guo, Huinan; Ren, Long; Zhou, Zuofeng

    2015-07-01

    Camera calibration is one of the essential steps in the computer vision research. This paper describes a real-time OpenCV based camera calibration system, and developed and implemented in the VS2008 environment. Experimental results prove that the system to achieve a simple and fast camera calibration, compared with MATLAB, higher precision and does not need manual intervention, and can be widely used in various computer vision system.

  6. Acoustic Self-Calibrating System for Indoor Smart Phone Tracking

    Directory of Open Access Journals (Sweden)

    Alexander Ens

    2015-01-01

    Full Text Available This paper presents an acoustic indoor localization system for commercial smart phones that emit high pitched acoustic signals beyond the audible range. The acoustic signals with an identifier code modulated on the signal are detected by self-built receivers which are placed at the ceiling or on walls in a room. The receivers are connected in a Wi-Fi network, such that they synchronize their clocks and exchange the time differences of arrival (TDoA of the received chirps. The location of the smart phone is calculated by TDoA multilateration. The precise time measuring of sound enables high precision localization in indoor areas. Our approach enables applications that require high accuracy, such as finding products in a supermarket or guiding blind people through complicated buildings. We have evaluated our system in real-world experiments using different algorithms for calibration-free localization and different types of sound signals. The adaptive GOGO-CFAR threshold enables a detection of 48% of the chirp pulses even at a distance of 30 m. In addition, we have compared the trajectory of a pedestrian carrying a smart phone to reference positions of an optic system. Consequently, the localization error is observed to be less than 30 cm.

  7. Accurate and Simple Calibration of DLP Projector Systems

    DEFF Research Database (Denmark)

    Wilm, Jakob; Olesen, Oline Vinter; Larsen, Rasmus

    2014-01-01

    Much work has been devoted to the calibration of optical cameras, and accurate and simple methods are now available which require only a small number of calibration targets. The problem of obtaining these parameters for light projectors has not been studied as extensively and most current methods...

  8. SU-E-T-105: Development of 3D Dose Verification System for Volumetric Modulated Arc Therapy Using Improved Polyacrylamide-Based Gel Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Ono, K; Fujimoto, S; Akagi, Y; Hirokawa, Y [Hiroshima Heiwa Clinic, Hiroshima (Japan); Hayashi, S [Hiroshima International University, Hiroshima (Japan); Miyazawa, M [R-TECH.INC, Toukyo (Japan)

    2014-06-01

    Purpose: The aim of this dosimetric study was to develop 3D dose verification system for volumetric modulated arc therapy (VMAT) using polyacrylamide-based gel (PAGAT) dosimeter improved the sensitivity by magnesium chloride (MgCl{sub 2}). Methods: PAGAT gel containing MgCl{sub 2} as a sensitizer was prepared in this study. Methacrylic-acid-based gel (MAGAT) was also prepared to compare the dosimetric characteristics with PAGAT gel. The cylindrical glass vials (4 cm diameter, 12 cm length) filled with each polymer gel were irradiated with 6 MV photon beam using Novalis Tx linear accelerator (Varian/BrainLAB). The irradiated polymer gel dosimeters were scanned with Signa 1.5 T MRI system (GE), and dose calibration curves were obtained using T{sub 2} relaxation rate (R{sub 2} = 1/T{sub 2}). Dose rate (100-600 MU min{sup −1}) and fractionation (1-8 fractions) were varied. In addition, a cubic acrylic phantom (10 × 10 × 10 cm{sup 3}) filled with improved PAGAT gel inserted into the IMRT phantom (IBA) was irradiated with VMAT (RapidArc). C-shape structure was used for the VMAT planning by the Varian Eclipse treatment planning system (TPS). The dose comparison of TPS and measurements with the polymer gel dosimeter was accomplished by the gamma index analysis, overlaying the dose profiles for a set of data on selected planes using in-house developed software. Results: Dose rate and fractionation dependence of improved PAGAT gel were smaller than MAGAT gel. A high similarity was found by overlaying the dose profiles measured with improved PAGAT gel dosimeter and the TPS dose, and the mean pass rate of the gamma index analysis using 3%/3 mm criteria was achieved 90% on orthogonal planes for VMAT using improved PAGAT gel dosimeter. Conclusion: In-house developed 3D dose verification system using improved polyacrylamide-based gel dosimeter had a potential as an effective tool for VMAT QA.

  9. Influence of fluid-mechanical characteristics of the system on the volumetric mass transfer coefficient and gas dispersion in three-phase system

    Directory of Open Access Journals (Sweden)

    Knežević Milena M.

    2014-01-01

    Full Text Available Distribution of gas bubbles and volumetric mass transfer coefficient, Kla, in a three phase system, with different types of solid particles at different operation conditions were studied in this paper. The ranges of superficial gas and liquid velocities used in this study were 0,03-0,09 m/s and 0-0,1 m/s, respectively. The three different types of solid particles were used as a bed in the column (glass dp=3 mm, dp=6 mm; ceramic dp=6 mm. The experiments were carried out in a 2D plexiglas column, 278 x 20,4 x 500 mm and in a cylindrical plexiglas column, with a diameter of 64 mm and a hight of 2000 mm. The Kla coefficient increased with gas and liquid velocities. Results showed that the volumetric mass transfer coefficient has a higher values in three phase system, with solid particles, compared with two phase system. The particles properties (diameter and density have a major impact on oxygen mass transfer in three phase systems.

  10. Pretreatment quality assurance of volumetric modulated arc therapy on patient CT scan using indirect 3D dosimetry system

    Directory of Open Access Journals (Sweden)

    Shanmugam Thirumalai Swamy

    2014-12-01

    Full Text Available Purpose: Aim of this study is to clinically implement the COMPASS 3D dosimetry system for pretreatment quality assurance of volumetric modulated arc therapy (VMAT-RapidArc treatment plans. Methods: For this study, 10 head and neck (H&N and 10 pelvis VMAT plans dose response from Linac was measured using COMPASS system along with MatriXXEvolution and 3D dose was reconstructed in the patient computed tomography (CT scan. Dose volume histograms and 3D gamma were used to evaluate the difference between the measured and calculated values. In order to validate the COMPASS system, dose response for open fields were acquired for both homogeneous and inhomogeneous phantoms. Results: The average dose difference between Eclipse treatment planning system (TPS calculated and COMPASS measured (homogenous medium in normalization region, inner region, penumbra region and buildup region was less than ±2%. In inhomogeneous phantom, there was a maximum difference of -3.17% in lung, whereas the difference other densities was within ±2%. The systematic increase in the average 3D gamma between the TPS calculated and COMPASS measured for VMAT plans with known dose errors and multi-leaf collimator (MLC offset errors shows that COMPASS system was sensitive enough to find clinical significant errors. The 3D dose parameters (D95, D1, and average dose of all H&N and pelvis patients were well within the clinically acceptable tolerance level of ±5%. The average 3D gammas for planning target volumes (PTV and organ at risks (OAR of the patients were less than 0.6. Conclusion: The results from this study show that COMPASS along with MatriXXEvolution can be effectively used for pretreatment verification of VMAT plans in the patient anatomy.

  11. Electronics and Calibration system for the CMS Beam Halo Monitor

    CERN Document Server

    Tosi, Nicolo

    2014-01-01

    In the context of increasing luminosity of LHC, it will be important to accurately measure the Machine Induced Background. A new monitoring system will be installed in the CMS cavern for measuring the beam background at high radius. This detector is composed of synthetic quartz Cherenkov radiators, coupled to fast photomultiplier tubes (PMT). The readout chain of this detector will make use of many components developed for the Phase 1 upgrade to the CMS Hadron Calorimeter electronics, with a dedicated firmware and readout adapted to the beam monitoring requirements. The PMT signal will be digitized by a charge integrating ASIC (QIE10), providing both the signal rise time and the charge integrated over one bunch crossing.The backend electronics will record bunch-by-bunch histograms, which will be published to CMS and the LHC using the newly designed CMS beam instrumentation specific DAQ. A calibration monitoring system has been designed to generate triggered pulses of light to monitor the efficiency of the sys...

  12. A Novel Volumetric 3D Display System with Static Screen Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The physical world around us is three-dimensional (3D), yet most existing display systems with flat screens can handle only two-dimensional (2D) flat images that...

  13. Mammography calibration qualities establishment in a Mo-Mo clinical system

    Energy Technology Data Exchange (ETDEWEB)

    Correa, E.L.; Santos, L.R. dos; Vivolo, V.; Potiens, M.P.A., E-mail: educorrea1905@gmail.com [Instituto de Pesquisas Energeticas e Nucleres (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    In this study the mammography calibration qualities were established in a clinical mammography system. The objective is to provide the IPEN instruments calibration laboratory with both mammography calibration methods (using a clinical and an industrial system). The results showed a good behavior of mammography equipment, in terms of kVp, PPV and exposure time. The additional filtration of molybdenum is adequate, air-kerma rates were determined and spectra were obtained. (author)

  14. Quantitative Techniques in Volumetric Analysis

    Science.gov (United States)

    Zimmerman, John; Jacobsen, Jerrold J.

    1996-12-01

    Quantitative Techniques in Volumetric Analysis is a visual library of techniques used in making volumetric measurements. This 40-minute VHS videotape is designed as a resource for introducing students to proper volumetric methods and procedures. The entire tape, or relevant segments of the tape, can also be used to review procedures used in subsequent experiments that rely on the traditional art of quantitative analysis laboratory practice. The techniques included are: Quantitative transfer of a solid with a weighing spoon Quantitative transfer of a solid with a finger held weighing bottle Quantitative transfer of a solid with a paper strap held bottle Quantitative transfer of a solid with a spatula Examples of common quantitative weighing errors Quantitative transfer of a solid from dish to beaker to volumetric flask Quantitative transfer of a solid from dish to volumetric flask Volumetric transfer pipet A complete acid-base titration Hand technique variations The conventional view of contemporary quantitative chemical measurement tends to focus on instrumental systems, computers, and robotics. In this view, the analyst is relegated to placing standards and samples on a tray. A robotic arm delivers a sample to the analysis center, while a computer controls the analysis conditions and records the results. In spite of this, it is rare to find an analysis process that does not rely on some aspect of more traditional quantitative analysis techniques, such as careful dilution to the mark of a volumetric flask. Figure 2. Transfer of a solid with a spatula. Clearly, errors in a classical step will affect the quality of the final analysis. Because of this, it is still important for students to master the key elements of the traditional art of quantitative chemical analysis laboratory practice. Some aspects of chemical analysis, like careful rinsing to insure quantitative transfer, are often an automated part of an instrumental process that must be understood by the

  15. Calibration and validation of measurement system. Wave Dragon, Nissum Bredning

    Energy Technology Data Exchange (ETDEWEB)

    Kofoed, J.P-; Riemann, S.; Knapp, W.

    2004-03-01

    This report deals with the calibration of the measuring equipment on board the Wave Dragon, Nissum Bredning (WD-NB) prototype. The report covers the following instruments on board WD-NB: 1) Pressure transducers. 2) Force transducers. 3) Accelerometers. 4) Displacement sensors. 5) Strain gauges. 6) Inclinometers. All of these instruments are connected to the HBM MGC+ amplifier and data acquisition unit. In the following the calibration will be dealt with individually. Furthermore, a preliminary calibration of the siphon and dummy turbines has been carried out and this is also described in the following. (au)

  16. Visualising three-dimensional volumetric data with an arbitrary coordinate system

    CERN Document Server

    Taylor, Rhys

    2016-01-01

    Astronomical data does not always use Cartesian coordinates. Both all-sky observational data and simulations of rotationally symmetric systems, such as accretion and protoplanetary discs, may use spherical polar or other coordinate systems. Standard displays rely on Cartesian coordinates, but converting non-Cartesian data into Cartesian format causes distortion of the data and loss of detail. I here demonstrate a method using standard techniques from computer graphics that avoids these problems with 3D data in arbitrary coordinate systems. The method adds minimum computational cost to the display process and is suitable for both realtime, interactive content and producing fixed rendered images and videos. Proof-of-concept code is provided which works for data in spherical polar coordinates.

  17. Visualizing Three-dimensional Volumetric Data with an Arbitrary Coordinate System

    Science.gov (United States)

    Taylor, R.

    2017-02-01

    Astronomical data does not always use Cartesian coordinates. Both all-sky observational data and simulations of rotationally symmetric systems, such as accretion and protoplanetary disks, may use spherical polar or other coordinate systems. Standard displays rely on Cartesian coordinates, but converting non-Cartesian data into Cartesian format causes distortion of the data and loss of detail. Here, I demonstrate a method using standard techniques from computer graphics that avoids these problems with three-dimensional data in arbitrary coordinate systems. The method adds minimum computational cost to the display process and is suitable for both realtime, interactive content, and producing fixed rendered images and videos. Proof-of-concept code is provided which works for data in spherical polar coordinates.

  18. Test Facility for Volumetric Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, M.; Dibowski, G.; Pfander, M.; Sack, J. P.; Schwarzbozl, P.; Ulmer, S.

    2006-07-01

    Long-time testing of volumetric absorber modules is an inevitable measure to gain the experience and reliability required for the commercialization of the open volumetric receiver technology. While solar tower test facilities are necessary for performance measurements of complete volumetric receivers, the long-term stability of individual components can be tested in less expensive test setups. For the qualification of the aging effects of operating cycles on single elements of new absorber materials and designs, a test facility was developed and constructed in the framework of the KOSMOSOL project. In order to provide the concentrated solar radiation level, the absorber test facility is integrated into a parabolic dish system at the Plataforma Solar de Almeria (PSA) in Spain. Several new designs of ceramic absorbers were developed and tested during the last months. (Author)

  19. Volumetric properties under pressure for the binary system ethanol plus toluene

    DEFF Research Database (Denmark)

    Zeberg-Mikkelsen, Claus Kjær; Lugo, Luis; García, Josefa

    2005-01-01

    The density of the asymmetrical binary system composed of ethanol and toluene has been measured under pressure using a vibrating tube densimeter. The measurements have been performed for nine different compositions including the pure compounds at eight temperatures in the range 283.15–353.15 K....... At several temperatures the isobaric thermal expansion shows an non-monotonical behavior versus composition, whereas the excess molar volumes reveal a complex sigmoid behavior. These results have been interpreted as changes in the free-volume and as the formation and weakening of the molecular interactions....... The VLE behavior of this binary system within the considered temperature range is represented satisfactory by the perturbed-chain statistical association fluid theory (PC-SAFT) equation of state with a single interaction parameter, although no cross association between ethanol and toluene is taken...

  20. Seismic Monitoring System Calibration Using Ground Truth Database

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Winston; Wagner, Robert

    2002-12-22

    Calibration of a seismic monitoring system remains a major issue due to the lack of ground truth information and uncertainties in the regional geological parameters. Rapid and accurate identification of seismic events is currently not feasible due to the absence of a fundamental framework allowing immediate access to ground truth information for many parts of the world. Precise location and high-confidence identification of regional seismic events are the primary objectives of monitoring research in seismology. In the Department of Energy Knowledge Base (KB), ground truth information addresses these objectives and will play a critical role for event relocation and identification using advanced seismic analysis tools. Maintaining the KB with systematic compilation and analysis of comprehensive sets of geophysical data from various parts of the world is vital. The goal of this project is to identify a comprehensive database for China using digital seismic waveform data that are currently unavailable. These data may be analyzed along with ground truth information that becomes available. To date, arrival times for all regional phases are determined on all events above Mb 4.5 that occurred in China in 2000 and 2001. Travel-time models are constructed to compare with existing models. Seismic attenuation models may be constructed to provide better understanding of regional wave propagation in China with spatial resolution that has not previously been obtained.

  1. Comparison of the accuracy of the calibration model on the double and single integrating sphere systems

    CSIR Research Space (South Africa)

    Singh, A

    2011-05-01

    Full Text Available The accuracy of the calibration model for the single and double integrating sphere systems are compared for a white light system. A calibration model is created from a matrix of samples with known absorption and reduced scattering coefficients...

  2. Micromechanical analysis of volumetric growth in the context of open systems thermodynamics and configurational mechanics. Application to tumor growth

    Science.gov (United States)

    Ganghoffer, J. F.; Boubaker, M. B.

    2016-11-01

    We adopt in this paper the physically and micromechanically motivated point of view that growth (resp. resorption) occurs as the expansion (resp. contraction) of initially small tissue elements distributed within a host surrounding matrix, due to the interfacial motion of their boundary. The interface motion is controlled by the availability of nutrients and mechanical driving forces resulting from the internal stresses that built in during the growth. A general extremum principle of the zero potential for open systems witnessing a change of their mass due to the diffusion of nutrients is constructed, considering the framework of open systems thermodynamics. We postulate that the shape of the tissue element evolves in such a way as to minimize the zero potential among all possible admissible shapes of the growing tissue elements. The resulting driving force for the motion of the interface sets a surface growth models at the scale of the growing tissue elements, and is conjugated to a driving force identified as the interfacial jump of the normal component of an energy momentum tensor, in line with Hadamard's structure theorem. The balance laws associated with volumetric growth at the mesoscopic level result as the averaging of surface growth mechanisms occurring at the microscopic scale of the growing tissue elements. The average kinematics has been formulated in terms of the effective growth velocity gradient and elastic rate of deformation tensor, both functions of time. This formalism is exemplified by the simulation of the avascular growth of multicell spheroids in the presence of diffusion of nutrients, showing the respective influence of mechanical and chemical driving forces in relation to generation of internal stresses.

  3. Micromechanical analysis of volumetric growth in the context of open systems thermodynamics and configurational mechanics. Application to tumor growth

    Science.gov (United States)

    Ganghoffer, J. F.; Boubaker, M. B.

    2017-03-01

    We adopt in this paper the physically and micromechanically motivated point of view that growth (resp. resorption) occurs as the expansion (resp. contraction) of initially small tissue elements distributed within a host surrounding matrix, due to the interfacial motion of their boundary. The interface motion is controlled by the availability of nutrients and mechanical driving forces resulting from the internal stresses that built in during the growth. A general extremum principle of the zero potential for open systems witnessing a change of their mass due to the diffusion of nutrients is constructed, considering the framework of open systems thermodynamics. We postulate that the shape of the tissue element evolves in such a way as to minimize the zero potential among all possible admissible shapes of the growing tissue elements. The resulting driving force for the motion of the interface sets a surface growth models at the scale of the growing tissue elements, and is conjugated to a driving force identified as the interfacial jump of the normal component of an energy momentum tensor, in line with Hadamard's structure theorem. The balance laws associated with volumetric growth at the mesoscopic level result as the averaging of surface growth mechanisms occurring at the microscopic scale of the growing tissue elements. The average kinematics has been formulated in terms of the effective growth velocity gradient and elastic rate of deformation tensor, both functions of time. This formalism is exemplified by the simulation of the avascular growth of multicell spheroids in the presence of diffusion of nutrients, showing the respective influence of mechanical and chemical driving forces in relation to generation of internal stresses.

  4. SU-E-T-540: Volumetric Modulated Total Body Irradiation Using a Rotational Lazy Susan-Like Immobilization System

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X; Hrycushko, B; Lee, H; Lamphier, R; Jiang, S; Abdulrahman, R; Timmerman, R [UT Southwestern Medical Center, Dallas, TX (United States)

    2014-06-01

    Purpose: Traditional extended SSD total body irradiation (TBI) techniques can be problematic in terms of patient comfort and/or dose uniformity. This work aims to develop a comfortable TBI technique that achieves a uniform dose distribution to the total body while reducing the dose to organs at risk for complications. Methods: To maximize patient comfort, a lazy Susan-like couch top immobilization system which rotates about a pivot point was developed. During CT simulation, a patient is immobilized by a Vac-Lok bag within the body frame. The patient is scanned head-first and then feet-first following 180° rotation of the frame. The two scans are imported into the Pinnacle treatment planning system and concatenated to give a full-body CT dataset. Treatment planning matches multiple isocenter volumetric modulated arc (VMAT) fields of the upper body and multiple isocenter parallel-opposed fields of the lower body. VMAT fields of the torso are optimized to satisfy lung dose constraints while achieving a therapeutic dose to the torso. The multiple isocenter VMAT fields are delivered with an indexed couch, followed by body frame rotation about the pivot point to treat the lower body isocenters. The treatment workflow was simulated with a Rando phantom, and the plan was mapped to a solid water slab phantom for point- and film-dose measurements at multiple locations. Results: The treatment plan of 12Gy over 8 fractions achieved 80.2% coverage of the total body volume within ±10% of the prescription dose. The mean lung dose was 8.1 Gy. All ion chamber measurements were within ±1.7% compared to the calculated point doses. All relative film dosimetry showed at least a 98.0% gamma passing rate using a 3mm/3% passing criteria. Conclusion: The proposed patient comfort-oriented TBI technique provides for a uniform dose distribution within the total body while reducing the dose to the lungs.

  5. Combined Calibration Method and its Realization for Direction Finding Antenna Systems with Patch Antennas

    Directory of Open Access Journals (Sweden)

    R. Seller

    2007-09-01

    Full Text Available A novel radio channel compensation method aiming to give optimal calibration for microstrip antenna array systems is presented in this paper, realized for an actual DOA measurement antenna system using microstrip antennas to sample the electromagnetic field, operating at 4.5GHz. This new approach considers mismatch between antennas and channel RF ports, channel transmission inequalities, and also decreases the effects of multipath propagation components of calibration reference signals by placing the calibration reference signal feeding network on the microstrip antenna array bearer, directly beside the antenna patches. It is combined with orthogonal spread spectrum calibration signal utility for continuous uninterrupted measurements. The spread spectrum calibration signal is orthogonal to the continuous wave (CW signal to be measured, therefore, the 2 signals can be separated in the receiver, enabling them to be present simultaneously. DOA measurement results are shown, measured with the realized integrated microstrip patch antenna array with calibration network hardware.

  6. Development of Polymer Gel Systems to Improve Volumetric Sweep and Reduce Producing Water/Oil Ratios

    Energy Technology Data Exchange (ETDEWEB)

    G. Paul Willhite; Stan McCool; Don W. Green; Min Cheng; Feiyan Chen

    2005-12-31

    Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of a 42-month research program that focused on the understanding of gelation chemistry and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work was conducted on a widely applied system in the field, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. Pre-gel aggregates form and grow as reactions between chromium acetate and polyacrylamide proceed. A rate equation that describes the reaction between chromium acetate and polymer molecules was regressed from experimental data. A mathematical model that describes the crosslinking reaction between two polymer molecules as a function of time was derived. The model was based on probability concepts and provides molecular-weight averages and molecular-weight distributions of the pre-gel aggregates as a function of time and initial system conditions. Average molecular weights of pre-gel aggregates were measured as a function of time and were comparable to model simulations. Experimental methods to determine molecular weight distributions of pre-gel aggregates were unsuccessful. Dissolution of carbonate minerals during the injection of gelants causes the pH of the gelant to increase. Chromium precipitates from solution at the higher pH values robbing the gelant of crosslinker. Experimental data on the transport of chromium acetate solutions through dolomite cores were obtained. A mathematical model that describes the transport of brine and chromium acetate solutions through rocks containing carbonate minerals was used to simulate the experimental results and data from literature. Gel treatments usually reduce the permeability

  7. DEVELOPMENT OF POLYMER GEL SYSTEMS TO IMPROVE VOLUMETRIC SWEEP AND REDUCE PRODUCING WATER/OIL RATIOS

    Energy Technology Data Exchange (ETDEWEB)

    G. Paul Willhite; Stan McCool; Don W. Green; Min Cheng; Rajeev Jain; Tuan Nguyen

    2003-11-01

    Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of the first year of a three-year research program that is aimed at the understanding of the chemistry of gelation and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work has focused on a widely-applied system in field applications, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. The initial reaction between chromium acetate and one polymer is referred to as the uptake reaction. The uptake reaction was studied as functions of chromium and polymer concentrations and pH values. Experimental data were regressed to determine a rate equation that describes the uptake reaction of chromium by polyacrylamide. Pre-gel aggregates form and grow as the reactions between chromium acetate and polyacrylamide proceed. A statistical model that describes the growth of pre-gel aggregates was developed using the theory of branching processes. The model gives molecular weight averages that are expressed as functions of the conversion of the reactive sites on chromium acetate or on the polymer molecule. Results of the application of the model correlate well with experimental data of viscosity and weight-average molecular weight and gives insights into the gelation process. A third study addresses the flow of water and oil in rock material after a gel treatment. Previous works have shown that gel treatments usually reduce the permeability to water to a greater extent than the permeability to oil is reduced. This phenomenon is referred to as disproportionate permeability reduction (DPR). Flow experiments were conducted to determine the effect of polymer and chromium concentrations on

  8. Comparative analysis of volumetric flow meters used for mass flow estimation in multiphase and multidensity environments

    Science.gov (United States)

    Pedone, Richard; Korman, Valentin; Wiley, John T.

    2006-05-01

    Accurate and reliable multiphase flow measurements are needed for liquid propulsion systems. Existing volumetric flow meters are adequate for flow measurements with well-characterized, clean liquids and gases. However, these technologies are inadequate for multiphase environments, such as cryogenic fluids. Although, properly calibrated turbine flow meters can provide highly accurate and repeatable data, problems are still prevalent with multiphase flows. Limitations are thus placed on the applicability of intrusive turbine flow meters.

  9. Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yidong, E-mail: yidongyang@med.miami.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 and Department of Radiation Oncology, University of Miami School of Medicine, Miami, Florida 33136 (United States); Wang, Ken Kang-Hsin; Wong, John W. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States); Eslami, Sohrab; Iordachita, Iulian I. [Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Patterson, Michael S. [Juravinski Cancer Centre and Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S4K1 (Canada)

    2015-04-15

    Purpose: The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides excellent bone to soft tissue contrast, but is incapable of differentiating tumors from surrounding soft tissue. Bioluminescence tomography (BLT), in contrast, allows direct visualization of even subpalpable tumors and quantitative evaluation of tumor response. Integration of BLT with CBCT offers complementary image information, with CBCT delineating anatomic structures and BLT differentiating luminescent tumors. This study is to develop a systematic method to calibrate an integrated CBCT and BLT imaging system which can be adopted onboard the SARRP to guide focal tumor irradiation. Methods: The integrated imaging system consists of CBCT, diffuse optical tomography (DOT), and BLT. The anatomy acquired from CBCT and optical properties acquired from DOT serve as a priori information for the subsequent BLT reconstruction. Phantoms were designed and procedures were developed to calibrate the CBCT, DOT/BLT, and the entire integrated system. Geometrical calibration was performed to calibrate the CBCT system. Flat field correction was performed to correct the nonuniform response of the optical imaging system. Absolute emittance calibration was performed to convert the camera readout to the emittance at the phantom or animal surface, which enabled the direct reconstruction of the bioluminescence source strength. Phantom and mouse imaging were performed to validate the calibration. Results: All calibration procedures were successfully performed. Both CBCT of a thin wire and a euthanized mouse revealed no spatial artifact, validating the accuracy of the CBCT calibration. The absolute emittance calibration was validated with a 650 nm laser source, resulting in a 3

  10. Preparation of CLA ascorbyl ester with improved volumetric productivity by an ionic liquid-based reaction system

    DEFF Research Database (Denmark)

    Chen, B.L.; Guo, Zheng; Let, M.B.

    2008-01-01

    A new approach to the enzymatic production Of conjugated linoleic acid (CLA) ascorbyl ester with a remarkably high volumetric productivity (120-200 g L-1) has been developed, in which strong solvation by tOMA-TFA (methyltrioctylammonium trifluoroacetate) enables a high concentration of ascorbic...

  11. Experimental Results of Site Calibration and Sensitivity Measurements in OTR for UWB Systems

    Science.gov (United States)

    Viswanadham, Chandana; Rao, P. Mallikrajuna

    2016-08-01

    System calibration and parameter accuracy measurement of electronic support measures (ESM) systems is a major activity, carried out by electronic warfare (EW) engineers. These activities are very critical and needs good understanding in the field of microwaves, antennas, wave propagation, digital and communication domains. EW systems are broad band, built with state-of-the art electronic hardware, installed on different varieties of military platforms to guard country's security from time to time. EW systems operate in wide frequency ranges, typically in the order of thousands of MHz, hence these are ultra wide band (UWB) systems. Few calibration activities are carried within the system and in the test sites, to meet the accuracies of final specifications. After calibration, parameters are measured for their accuracies either in feed mode by injecting the RF signals into the front end or in radiation mode by transmitting the RF signals on to system antenna. To carry out these activities in radiation mode, a calibrated open test range (OTR) is necessary in the frequency band of interest. Thus site calibration of OTR is necessary to be carried out before taking up system calibration and parameter measurements. This paper presents the experimental results of OTR site calibration and sensitivity measurements of UWB systems in radiation mode.

  12. The Photomultiplier Tube Calibration System of the MicroBooNE Experiment

    CERN Document Server

    Conrad, J; Moss, Z; Strauss, T; Toups, M

    2015-01-01

    We report on the design and construction of an LED-based fiber calibration system for large liquid argon time projection detectors. This system was developed to calibrate the optical systems of the MicroBooNE experiment. As well as detailing the materials and installation procedure, we provide technical drawings and specifications so that the system may be easily replicated in future LArTPC detectors.

  13. A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph

    CERN Document Server

    Doerr, H -P; Holzwarth, R; Schmidt, T Kentischer und W

    2012-01-01

    A wavelength calibration system based on a laser frequency comb (LFC) was developed in a co-operation between the Kiepenheuer-Institut f\\"ur Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut f\\"ur Quantenoptik, Garching, Germany for permanent installation at the German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands. The system was installed successfully in October 2011. By simultaneously recording the spectra from the Sun and the LFC, for each exposure a calibration curve can be derived from the known frequencies of the comb modes that is suitable for absolute calibration at the meters per second level. We briefly summarize some topics in solar physics that benefit from absolute spectroscopy and point out the advantages of LFC compared to traditional calibration techniques. We also sketch the basic setup of the VTT calibration system and its integration with the existing echelle spectrograph.

  14. Novel calibration method for structured-light system with an out-of-focus projector.

    Science.gov (United States)

    Li, Beiwen; Karpinsky, Nikolaus; Zhang, Song

    2014-06-01

    A structured-light system with a binary defocusing technique has the potential to have more extensive application due to its high speeds, gamma-calibration-free nature, and lack of rigid synchronization requirements between the camera and projector. However, the existing calibration methods fail to achieve high accuracy for a structured-light system with an out-of-focus projector. This paper proposes a method that can accurately calibrate a structured-light system even when the projector is not in focus, making it possible for high-accuracy and high-speed measurement with the binary defocusing method. Experiments demonstrate that our calibration approach performs consistently under different defocusing degrees, and a root-mean-square error of about 73 μm can be achieved with a calibration volume of 150(H) mm×250(W) mm×200(D)mm.

  15. A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph

    Science.gov (United States)

    Doerr, H.-P.; Steinmetz, T.; Holzwarth, R.; Kentischer, T.; Schmidt, W.

    2012-10-01

    A wavelength calibration system based on a laser frequency comb (LFC) was developed in a co-operation between the Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut für Quantenoptik, Garching, Germany for permanent installation at the German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands. The system was installed successfully in October 2011. By simultaneously recording the spectra from the Sun and the LFC, for each exposure a calibration curve can be derived from the known frequencies of the comb modes that is suitable for absolute calibration at the meters per second level. We briefly summarize some topics in solar physics that benefit from absolute spectroscopy and point out the advantages of LFC compared to traditional calibration techniques. We also sketch the basic setup of the VTT calibration system and its integration with the existing echelle spectrograph.

  16. Opticle fibre calibration system and adaptive power supply

    CERN Document Server

    Cvach, J; Kovalcuk, M; Kvasnicka, J; Polak, I; Smolik, J

    2015-01-01

    We summarize the recent activity of our group in the calibration, monitoring and gain stabilization of photodetectors, primarily silicon photomultipliers, in calorimeters using scintillator as active medium. The task originally solved for the CALICE analog hadron calorimeter founds application in other experiments.

  17. Calibration of an Automatic System Using a Laser Signature

    Directory of Open Access Journals (Sweden)

    Edward F. Plinski

    2003-04-01

    Full Text Available The specific phenomenon, which appears in tuned CO2 lasers, called a laser signature, is used as a standard for calibration of the servomechanism. The proposed servomechanism can be used for continuous investigations of the laser signatures of different laser media.

  18. An Incremental Target-Adapted Strategy for Active Geometric Calibration of Projector-Camera Systems

    Directory of Open Access Journals (Sweden)

    Hsiang-Jen Chien

    2013-02-01

    Full Text Available The calibration of a projector-camera system is an essential step toward accurate 3-D measurement and environment-aware data projection applications, such as augmented reality. In this paper we present a two-stage easy-to-deploy strategy for robust calibration of both intrinsic and extrinsic parameters of a projector. Two key components of the system are the automatic generation of projected light patterns and the incremental calibration process. Based on the incremental strategy, the calibration process first establishes a set of initial parameters, and then it upgrades these parameters incrementally using the projection and captured images of dynamically-generated calibration patterns. The scene-driven light patterns allow the system to adapt itself to the pose of the calibration target, such that the difficulty in feature detection is greatly lowered. The strategy forms a closed-loop system that performs self-correction as more and more observations become available. Compared to the conventional method, which requires a time-consuming process for the acquisition of dense pixel correspondences, the proposed method deploys a homography-based coordinate computation, allowing the calibration time to be dramatically reduced. The experimental results indicate that an improvement of 70% in reprojection errors is achievable and 95% of the calibration time can be saved.

  19. Leveraging microwave polarization information for calibration of a land data assimilation system

    Science.gov (United States)

    This letter contributes a new approach to calibrating a tau-omega radiative transfer model coupled to a land surface model with low frequency (< 10 GHz) microwave brightness temperature (TB) observations. The problem of calibrating this system is generally poorlyposed because various parameter combi...

  20. A self-calibration method for tri-axis rotational inertial navigation system

    Science.gov (United States)

    Gao, Pengyu; Li, Kui; Wang, Lei; Liu, Zengjun

    2016-11-01

    The navigation accuracy of the rotational inertial navigation system (RINS) could be greatly improved by periodically rotating the inertial measurement unit (IMU) with gimbals. However, error parameters in RINS should be effectively calibrated and compensated. In this paper, a self-calibration method is proposed for tri-axis RINS using attitude errors and velocity errors as measurements. The proposed calibration scheme is designed as three separate steps, and a certain gimbal rotates continuously in each step. All the error parameters in the RINS are calibrated when the whole scheme finishes. The separate calibration steps reduce the correlations between error parameters, and the observability of errors in this method is clear to demonstrate according to the relations between navigation errors and error parameters when gimbals rotate. Each calibration step only lasts 12 min, thus gyro drifts and accelerometers biases could be regarded as constant. The proposed calibration scheme is tested in both simulation and actual tri-axis RINS, and simulation and experimental results show that all 23 error parameters could be well estimated in tri-axis RINS. A long-term vehicle navigation experiment results show that after calibration and compensation, the navigation performance has doubled approximately, and the velocity accuracy is less than 2 m s-1 while the position accuracy is less than 1500 m, fully illustrating the significance of the proposed self-calibration method in improving the navigation performance of RINS.

  1. An accurate system for onsite calibration of electronic transformers with digital output

    Science.gov (United States)

    Zhi, Zhang; Li, Hong-Bin

    2012-06-01

    Calibration systems with digital output are used to replace conventional calibration systems because of principle diversity and characteristics of digital output of electronic transformers. But precision and unpredictable stability limit their onsite application even development. So fully considering the factors influencing accuracy of calibration system and employing simple but reliable structure, an all-digital calibration system with digital output is proposed in this paper. In complicated calibration environments, precision and dynamic range are guaranteed by A/D converter with 24-bit resolution, synchronization error limit is nanosecond by using the novelty synchronization method. In addition, an error correction algorithm based on the differential method by using two-order Hanning convolution window has good inhibition of frequency fluctuation and inter-harmonics interference. To verify the effectiveness, error calibration was carried out in the State Grid Electric Power Research Institute of China and results show that the proposed system can reach the precision class up to 0.05. Actual onsite calibration shows that the system has high accuracy, and is easy to operate with satisfactory stability.

  2. Resolution of a phase ambiguity in a calibration procedure for polarimetric radar systems

    Energy Technology Data Exchange (ETDEWEB)

    Sletten, M.A. (Naval Research Lab., Washington, DC (United States). Radar Div.)

    1994-01-01

    In response to the remote sensing communities' interest in radar polarimetry, considerable effort has recently been devoted to the development of calibration techniques for polarimetric radar systems. A cross-pol/co-pol phase ambiguity in a previously published calibration procedure for polarimetric radar systems is discussed. The original procedure is modified to resolve the ambiguity while still retaining insensitivity to calibration target orientation. The modified form is then generalized and applied to an ultrawideband radar system for which the ambiguity in the original procedure is particularly evident.

  3. Calibration and validation of a model describing complete autotrophic nitrogen removal in a granular SBR system

    DEFF Research Database (Denmark)

    Vangsgaard, Anna Katrine; Mutlu, Ayten Gizem; Gernaey, Krist

    2013-01-01

    -up. RESULTS: A model was calibrated using a step-wise procedure customized for the specific needs of the system. The important steps in the procedure were initialization, steady-state and dynamic calibration, and validation. A fast and effective initialization approach was developed to approximate pseudo...... screening of the parameter space proposed by Sin et al. (2008) - to find the best fit of the model to dynamic data. Finally, the calibrated model was validated with an independent data set. CONCLUSION: The presented calibration procedure is the first customized procedure for this type of system...... and is expected to contribute to achieve a fast and effective model calibration, an important enabling tool for various biochemical engineering design, control and operation problems....

  4. Computer-Based Simulation and Test System for the Calibration of EFI Engine

    Institute of Scientific and Technical Information of China (English)

    赵长禄; 张付军; 黄英; 葛蕴珊; 刘福水

    2004-01-01

    A computer-based simulation and test system is developed. This system has the following functions: producing the initial control MAP with good accuracy, calibrating the electronic control unit (ECU) on-line, identifying the dynamic transfer functions for air/fuel ratio, idle speed and ignition timing control. So the experiment work is reduced and the calibration is accelerated. In order to increase the simulation accuracy of the initial control MAP, the mathematical models are not only based on theoretical equations, but also on the control data of reference working points, which is obtained by the on-line calibration of special engines. The application of this system on a mini-car shows that the simulated control MAP has good accuracy, the interface of the system is friendly, the integrated simulation and test system is a powerful aid for EFI engine calibration and the development speed is accelerated.

  5. SU-D-BRC-07: System Design for a 3D Volumetric Scintillation Detector Using SCMOS Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Darne, C; Robertson, D; Alsanea, F; Beddar, S [UT MD Anderson Cancer Center, Houston, TX (United States)

    2016-06-15

    Purpose: The purpose of this project is to build a volumetric scintillation detector for quantitative imaging of 3D dose distributions of proton beams accurately in near real-time. Methods: The liquid scintillator (LS) detector consists of a transparent acrylic tank (20×20×20 cm{sup 3}) filled with a liquid scintillator that when irradiated with protons generates scintillation light. To track rapid spatial and dose variations in spot scanning proton beams we used three scientific-complementary metal-oxide semiconductor (sCMOS) imagers (2560×2160 pixels). The cameras collect optical signal from three orthogonal projections. To reduce system footprint two mirrors oriented at 45° to the tank surfaces redirect scintillation light to cameras for capturing top and right views. Selection of fixed focal length objective lenses for these cameras was based on their ability to provide large depth of field (DoF) and required field of view (FoV). Multiple cross-hairs imprinted on the tank surfaces allow for image corrections arising from camera perspective and refraction. Results: We determined that by setting sCMOS to 16-bit dynamic range, truncating its FoV (1100×1100 pixels) to image the entire volume of the LS detector, and using 5.6 msec integration time imaging rate can be ramped up to 88 frames per second (fps). 20 mm focal length lens provides a 20 cm imaging DoF and 0.24 mm/pixel resolution. Master-slave camera configuration enable the slaves to initiate image acquisition instantly (within 2 µsec) after receiving a trigger signal. A computer with 128 GB RAM was used for spooling images from the cameras and can sustain a maximum recording time of 2 min per camera at 75 fps. Conclusion: The three sCMOS cameras are capable of high speed imaging. They can therefore be used for quick, high-resolution, and precise mapping of dose distributions from scanned spot proton beams in three dimensions.

  6. Calibration of a flexible measurement system based on industrial articulated robot and structured light sensor

    Science.gov (United States)

    Mu, Nan; Wang, Kun; Xie, Zexiao; Ren, Ping

    2017-05-01

    To realize online rapid measurement for complex workpieces, a flexible measurement system based on an articulated industrial robot with a structured light sensor mounted on the end-effector is developed. A method for calibrating the system parameters is proposed in which the hand-eye transformation parameters and the robot kinematic parameters are synthesized in the calibration process. An initial hand-eye calibration is first performed using a standard sphere as the calibration target. By applying the modified complete and parametrically continuous method, we establish a synthesized kinematic model that combines the initial hand-eye transformation and distal link parameters as a whole with the sensor coordinate system as the tool frame. According to the synthesized kinematic model, an error model is constructed based on spheres' center-to-center distance errors. Consequently, the error model parameters can be identified in a calibration experiment using a three-standard-sphere target. Furthermore, the redundancy of error model parameters is eliminated to ensure the accuracy and robustness of the parameter identification. Calibration and measurement experiments are carried out based on an ER3A-C60 robot. The experimental results show that the proposed calibration method enjoys high measurement accuracy, and this efficient and flexible system is suitable for online measurement in industrial scenes.

  7. Alignment of the Measurement Scale Mark during Immersion Hydrometer Calibration Using an Image Processing System

    Directory of Open Access Journals (Sweden)

    Jose Emilio Vargas-Soto

    2013-10-01

    Full Text Available The present work presents an improved method to align the measurement scale mark in an immersion hydrometer calibration system of CENAM, the National Metrology Institute (NMI of Mexico, The proposed method uses a vision system to align the scale mark of the hydrometer to the surface of the liquid where it is immersed by implementing image processing algorithms. This approach reduces the variability in the apparent mass determination during the hydrostatic weighing in the calibration process, therefore decreasing the relative uncertainty of calibration.

  8. Parameter subset selection for the dynamic calibration of activated sludge models (ASMs): experience versus systems analysis

    DEFF Research Database (Denmark)

    Ruano, MV; Ribes, J; de Pauw, DJW

    2007-01-01

    In this work we address the issue of parameter subset selection within the scope of activated sludge model calibration. To this end, we evaluate two approaches: (i) systems analysis and (ii) experience-based approach. The evaluation has been carried out using a dynamic model (ASM2d) calibrated...... based approaches which excluded them from their analysis. Systems analysis reveals that parameter significance ranking and size of the identifiable parameter subset depend on the information content of data available for calibration. However, it suffers from heavy computational demand. In contrast...

  9. Alignment of the Measurement Scale Mark during Immersion Hydrometer Calibration Using an Image Processing System

    Science.gov (United States)

    Peña-Perez, Luis Manuel; Pedraza-Ortega, Jesus Carlos; Ramos-Arreguin, Juan Manuel; Arriaga, Saul Tovar; Fernandez, Marco Antonio Aceves; Becerra, Luis Omar; Hurtado, Efren Gorrostieta; Vargas-Soto, Jose Emilio

    2013-01-01

    The present work presents an improved method to align the measurement scale mark in an immersion hydrometer calibration system of CENAM, the National Metrology Institute (NMI) of Mexico, The proposed method uses a vision system to align the scale mark of the hydrometer to the surface of the liquid where it is immersed by implementing image processing algorithms. This approach reduces the variability in the apparent mass determination during the hydrostatic weighing in the calibration process, therefore decreasing the relative uncertainty of calibration. PMID:24284770

  10. General Calibration Algorithm for Single-transmitting-dual-receiving Polarimetric SAR System

    Directory of Open Access Journals (Sweden)

    Chen Lin

    2012-09-01

    Full Text Available The single-transmitting-dual-receiving polarimetric SAR system has only two receving channels, which induces lack of prior information for calibration. Due to the polarization diversity of this kind of system (which operates on different dual and compact polarimetric modes, there has not a general algorithm currently. In this paper, a new general calibration algorithm is proposed for single-transmitting-dual-receiving polarimetric SAR system, which can be widely applied to diverse polarization modes. The transmitting and receiving distortion can be estimated using trihedral, 0° dihedral and 45° dihedral as ideal point targets without any assumption on the scene and system. The basic principle of this new algorithm is induced theoretically. The effect of calibrator error on the distortion estimation is analyzed by simulation. Point targets’calibration results and polarization signatures verify this algorithm.

  11. 3D-Calibration for IMU of the Strapdown Inertial Navigation Systems

    Directory of Open Access Journals (Sweden)

    Avrutov V.V.

    2017-01-01

    Full Text Available A new calibration method for Inertial Measurement Unit (IMU of Strapdown Iner-tial Navigation Systems was presented. IMU has been composed of accelerometers, gyroscopes and a circuit of signal processing. Normally, a rate transfer test and multi-position tests are us-ing for IMU calibration. The new calibration method is based on whole angle rotation or finite rotation. In fact it’s suggested to turn over IMU around three axes simultaneously. In order to solve the equation of calibration, it is necessary to provide an equality of a rank of basic matrix into degree of basic matrix. The results of simulated IMU data presented to demonstrate the performance of the new calibration method.

  12. A NEW AUTOMATIC SYSTEM CALIBRATION OF MULTI-CAMERAS AND LIDAR SENSORS

    Directory of Open Access Journals (Sweden)

    M. Hassanein

    2016-06-01

    Full Text Available In the last few years, multi-cameras and LIDAR systems draw the attention of the mapping community. They have been deployed on different mobile mapping platforms. The different uses of these platforms, especially the UAVs, offered new applications and developments which require fast and accurate results. The successful calibration of such systems is a key factor to achieve accurate results and for the successful processing of the system measurements especially with the different types of measurements provided by the LIDAR and the cameras. The system calibration aims to estimate the geometric relationships between the different system components. A number of applications require the systems be ready for operation in a short time especially for disasters monitoring applications. Also, many of the present system calibration techniques are constrained with the need of special arrangements in labs for the calibration procedures. In this paper, a new technique for calibration of integrated LIDAR and multi-cameras systems is presented. The new proposed technique offers a calibration solution that overcomes the need for special labs for standard calibration procedures. In the proposed technique, 3D reconstruction of automatically detected and matched image points is used to generate a sparse images-driven point cloud then, a registration between the LIDAR generated 3D point cloud and the images-driven 3D point takes place to estimate the geometric relationships between the cameras and the LIDAR.. In the presented technique a simple 3D artificial target is used to simplify the lab requirements for the calibration procedure. The used target is composed of three intersected plates. The choice of such target geometry was to ensure enough conditions for the convergence of registration between the constructed 3D point clouds from the two systems. The achieved results of the proposed approach prove its ability to provide an adequate and fully automated

  13. a New Automatic System Calibration of Multi-Cameras and LIDAR Sensors

    Science.gov (United States)

    Hassanein, M.; Moussa, A.; El-Sheimy, N.

    2016-06-01

    In the last few years, multi-cameras and LIDAR systems draw the attention of the mapping community. They have been deployed on different mobile mapping platforms. The different uses of these platforms, especially the UAVs, offered new applications and developments which require fast and accurate results. The successful calibration of such systems is a key factor to achieve accurate results and for the successful processing of the system measurements especially with the different types of measurements provided by the LIDAR and the cameras. The system calibration aims to estimate the geometric relationships between the different system components. A number of applications require the systems be ready for operation in a short time especially for disasters monitoring applications. Also, many of the present system calibration techniques are constrained with the need of special arrangements in labs for the calibration procedures. In this paper, a new technique for calibration of integrated LIDAR and multi-cameras systems is presented. The new proposed technique offers a calibration solution that overcomes the need for special labs for standard calibration procedures. In the proposed technique, 3D reconstruction of automatically detected and matched image points is used to generate a sparse images-driven point cloud then, a registration between the LIDAR generated 3D point cloud and the images-driven 3D point takes place to estimate the geometric relationships between the cameras and the LIDAR.. In the presented technique a simple 3D artificial target is used to simplify the lab requirements for the calibration procedure. The used target is composed of three intersected plates. The choice of such target geometry was to ensure enough conditions for the convergence of registration between the constructed 3D point clouds from the two systems. The achieved results of the proposed approach prove its ability to provide an adequate and fully automated calibration without

  14. Test system calibrate used in DAM%DAM测试系统校准

    Institute of Scientific and Technical Information of China (English)

    张思敏; 盛永鑫

    2013-01-01

    The test system used in DAM is the critical equipment of the DAM, its performance has a direct impact on DAM. In order to solve the problem of the system calibration is not comprehensive and the automated calibration is not high, the in-site calibration idea is put forward. Through the analysis of the principle and the work process of the test system used in DAM,the calibration system of test system used in DAM is set up,the calibration adapter diagram and software composition are stated . This method has been proved to be good in versatility and high automation,can meet the calibration needs of the test system used in DAM .%DAM测试系统是DAM关键测试设备,它的性能会对DAM的性能指标有直接的影响,为了解决系统校准不全面和自动化程度不高的问题,提出了原位校准思路.通过对DAM测试系统原理和工作流程分析,构建DAM测试系统校准装置,阐述了校准适配网络组成和软件组成框图.经过实际应用证明,该方法通用性好,自动化程度高,满足DAM测试系统校准需求.

  15. Misalignment calibration of geomagnetic vector measurement system using parallelepiped frame rotation method

    Science.gov (United States)

    Pang, Hongfeng; Zhu, XueJun; Pan, Mengchun; Zhang, Qi; Wan, Chengbiao; Luo, Shitu; Chen, Dixiang; Chen, Jinfei; Li, Ji; Lv, Yunxiao

    2016-12-01

    Misalignment error is one key factor influencing the measurement accuracy of geomagnetic vector measurement system, which should be calibrated with the difficulties that sensors measure different physical information and coordinates are invisible. A new misalignment calibration method by rotating a parallelepiped frame is proposed. Simulation and experiment result show the effectiveness of calibration method. The experimental system mainly contains DM-050 three-axis fluxgate magnetometer, INS (inertia navigation system), aluminium parallelepiped frame, aluminium plane base. Misalignment angles are calculated by measured data of magnetometer and INS after rotating the aluminium parallelepiped frame on aluminium plane base. After calibration, RMS error of geomagnetic north, vertical and east are reduced from 349.441 nT, 392.530 nT and 562.316 nT to 40.130 nT, 91.586 nT and 141.989 nT respectively.

  16. Error Modeling, Calibration, and Nonlinear Interpolation Compensation Method of Ring Laser Gyroscope Inertial Navigation System

    Directory of Open Access Journals (Sweden)

    Jianli Li

    2013-01-01

    Full Text Available In order to improve the precision of Strapdown Inertial Navigation System (SINS and reduce the complexity of the traditional calibration method, a novel calibration and compensation scheme is proposed. An optimization calibration method with four-direction rotations is designed to calculate all error coefficients of Ring Laser Gyroscope (RLG SINS in a series of constant temperatures. According to the actual working environment, the temperature errors of RLG SINS are compensated by a nonlinear interpolation compensation algorithm. The experimental results show that the inertial navigation errors of the proposed method are reduced.

  17. IFIN-HH ionization chamber calibration and its validation; electrometric system improvement.

    Science.gov (United States)

    Sahagia, M; Wätjen, A C; Luca, A; Ivan, C

    2010-01-01

    The paper presents the results obtained in the calibration of the CENTRONIC IG12/20A ionization chamber for 18 gamma ray emitters, and its improvement with a Keithley 6517A electrometer. The calibration figures were determined either directly in pA MBq(-1) units, or calculated from old units, by using the system capacity value. The calibration figures, determined with RML's standards, are compared with those deduced from the KCRV or the mean of the comparisons, and the values determined at PTB-Germany.

  18. IFIN-HH ionization chamber calibration and its validation; electrometric system improvement

    Energy Technology Data Exchange (ETDEWEB)

    Sahagia, M., E-mail: msahagia@nipne.r [' Horia Hulubei' National Institute of R and D for Physics and Nuclear Engineering, IFIN-HH, P.O. Box MG-6, Bucharest, RO-77125 (Romania); Waetjen, A.C.; Luca, A.; Ivan, C. [' Horia Hulubei' National Institute of R and D for Physics and Nuclear Engineering, IFIN-HH, P.O. Box MG-6, Bucharest, RO-77125 (Romania)

    2010-07-15

    The paper presents the results obtained in the calibration of the CENTRONIC IG12/20A ionization chamber for 18 gamma ray emitters, and its improvement with a Keithley 6517A electrometer. The calibration figures were determined either directly in pA MBq{sup -1} units, or calculated from old units, by using the system capacity value. The calibration figures, determined with RML's standards, are compared with those deduced from the KCRV or the mean of the comparisons, and the values determined at PTB-Germany.

  19. Easy calibration method of vision system for in-situ measurement of strain of thin films

    Institute of Scientific and Technical Information of China (English)

    Jun-Hyub PARK; Dong-Joong KANG; Myung-Soo SHIN; Sung-Jo LIM; Son-Cheol YU; Kwang-Soo LEE; Jong-Eun HA; Sung-Hoon CHOA

    2009-01-01

    An easy calibration method was presented for in-situ measurement of displacement in the order of nanometer during micro-tensile test for thin films by using CCD camera as a sensing device. The calibration of the sensing camera in the system is a central element part to measure displacement in the order of nanometer using images taken with the camera. This was accomplished by modeling the optical projection through the camera lens and relative locations between the object and camera in 3D space. A set of known 3D points on a plane where the film is located on is projected to an image plane as input data. These points, known as a calibration points, are then used to estimate the projection parameters of the camera. In the measurement system of the micro-scale by CCD camera, the calibration data acquisition and one-to-one matching steps between the image and 3D planes need precise data extraction procedures and repetitive user's operation to calibrate the measuring devices. The lack of the robust image feature extraction and easy matching prevent the practical use of these methods. A data selection method was proposed to overcome these limitations and offer an easy and convenient calibration of a vision system that has the CCD camera and the 3D reference plane with calibration marks of circular type on the surface of the plane. The method minimizes the user's intervention such as the fine tuning of illumination system and provides an efficient calibration method of the vision system for in-situ axial displacement measurement of the micro-tensile materials.

  20. Multi-sensor calibration of low-cost magnetic, angular rate and gravity systems.

    Science.gov (United States)

    Lüken, Markus; Misgeld, Berno J E; Rüschen, Daniel; Leonhardt, Steffen

    2015-10-13

    We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF) magnetic, angular rate and gravity (MARG) sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN). The 9DOF MARG sensor is part of our recently-developed "Integrated Posture and Activity Network by Medit Aachen" (IPANEMA) BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is Sensors 2015, 15 25920 corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°.

  1. Multi-Sensor Calibration of Low-Cost Magnetic, Angular Rate and Gravity Systems

    Directory of Open Access Journals (Sweden)

    Markus Lüken

    2015-10-01

    Full Text Available We present a new calibration procedure for low-cost nine degrees-of-freedom (9DOF magnetic, angular rate and gravity (MARG sensor systems, which relies on a calibration cube, a reference table and a body sensor network (BSN. The 9DOF MARG sensor is part of our recently-developed “Integrated Posture and Activity Network by Medit Aachen” (IPANEMA BSN. The advantage of this new approach is the use of the calibration cube, which allows for easy integration of two sensor nodes of the IPANEMA BSN. One 9DOF MARG sensor node is thereby used for calibration; the second 9DOF MARG sensor node is used for reference measurements. A novel algorithm uses these measurements to further improve the performance of the calibration procedure by processing arbitrarily-executed motions. In addition, the calibration routine can be used in an alignment procedure to minimize errors in the orientation between the 9DOF MARG sensor system and a motion capture inertial reference system. A two-stage experimental study is conducted to underline the performance of our calibration procedure. In both stages of the proposed calibration procedure, the BSN data, as well as reference tracking data are recorded. In the first stage, the mean values of all sensor outputs are determined as the absolute measurement offset to minimize integration errors in the derived movement model of the corresponding body segment. The second stage deals with the dynamic characteristics of the measurement system where the dynamic deviation of the sensor output compared to a reference system is Sensors 2015, 15 25920 corrected. In practical validation experiments, this procedure showed promising results with a maximum RMS error of 3.89°.

  2. Amplitude variation in calibrated audiometer systems in Clinical Simulations

    Directory of Open Access Journals (Sweden)

    Christopher Barlow

    2014-01-01

    Full Text Available Manual pure tone audiometry is considered to be the gold standard for the assessment of hearing thresholds and has been in consistent use for a long period of time. An increased legislative requirement to monitor and screen workers, and an increasing amount of legislation relating to hearing loss is putting greater reliance on this as a tool. There are a number of questions regarding the degree of accuracy of pure tone audiometry when undertaken in field conditions, particularly relating to the difference in conditions between laboratory calibration and clinical or industrial screening use. This study analyzed the output sound pressure level of four different commercial audiometers, all using TDH39 headphones and each of which had recently undergone calibration at an appropriate laboratory. Levels were measured using a Bruël and Kjaer Head and Torso simulator, which accurately replicates the size and shape of a human head, including the ears. A clinical environment was simulated by a trained audiometrist replacing the headphones for each test. Tests were undertaken at three presentation levels, and at the frequencies of 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz and 6 kHz. The results showed a high level of test-retest variability, both between different audiometers and within the same audiometer. Maximum variation of sound pressure level at the ear for the same tone presentation was 21 decibels, with a particularly high level of variation at 6 kHz for all meters. An audiometer with attenuating cups exhibited significantly higher variation than ones using supral-aural headphones. Overall the variation exhibited suggests that there is a higher degree of potential error with screening pure tone audiometry than is commonly assumed and that results particularly at the 6 kHz frequency need to be assessed carefully alongside other methods such as speech audiometry.

  3. Design and calibration of a new high-definition three-dimensional laparoscopic system

    Institute of Scientific and Technical Information of China (English)

    Jia TANG; Li-qiang WANG‡; Bo YUAN; Hong JIANG; Qi-ming ZHU

    2015-01-01

    We present a high-definition (HD) 3D laparoscopic system including a dual channel optical system, two cameras, a camera control unit (CCU), and an HD 3D monitor. This laparoscopic system is capable of outputting dual high-definition videos and providing vivid 3D images. A modified pinhole camera model is used for camera calibration and a new method of depth measurement to improve precision. The average error of depth measurement measured by experiment (about 1.13 mm) was small in proportion to the large range in distance of the system (10–150 mm). The new method is applicable to any calibrated binocular vision system.

  4. Misalignment calibration of geomagnetic vector measurement system using parallelepiped frame rotation method

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Hongfeng [Academy of Equipment, Beijing 101416 (China); College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073 (China); Zhu, XueJun, E-mail: zhuxuejun1990@126.com [College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073 (China); Pan, Mengchun; Zhang, Qi; Wan, Chengbiao; Luo, Shitu; Chen, Dixiang; Chen, Jinfei; Li, Ji; Lv, Yunxiao [College of Mechatronics Engineering and Automation, National University of Defense Technology, Changsha 410073 (China)

    2016-12-01

    Misalignment error is one key factor influencing the measurement accuracy of geomagnetic vector measurement system, which should be calibrated with the difficulties that sensors measure different physical information and coordinates are invisible. A new misalignment calibration method by rotating a parallelepiped frame is proposed. Simulation and experiment result show the effectiveness of calibration method. The experimental system mainly contains DM-050 three-axis fluxgate magnetometer, INS (inertia navigation system), aluminium parallelepiped frame, aluminium plane base. Misalignment angles are calculated by measured data of magnetometer and INS after rotating the aluminium parallelepiped frame on aluminium plane base. After calibration, RMS error of geomagnetic north, vertical and east are reduced from 349.441 nT, 392.530 nT and 562.316 nT to 40.130 nT, 91.586 nT and 141.989 nT respectively. - Highlights: • A new misalignment calibration method by rotating a parallelepiped frame is proposed. • It does not need to know sensor attitude information or local dip angle. • The calibration system attitude change angle is not strictly required. • It can be widely used when sensors measure different physical information. • Geomagnetic vector measurement error is reduced evidently.

  5. A novel separation and calibration method for DVL and compass error in dead reckoning navigation systems

    Science.gov (United States)

    Zhang, Yanshun; Guo, Yajing; Yang, Tao; Li, Chunyu; Wang, Zhanqing

    2016-06-01

    The scale factor error δ C of the Doppler velocity log (DVL) and the heading angle error δ \\psi of a compass are so integrated in dead reckoning (DR) navigation systems that it is difficult to separate them. This paper aims to solve this problem by putting forward an online separation and calibration method for δ C and δ \\psi based on an ‘arc and linear’ trajectory. This method introduces the high-accuracy location information of a long base line (LBL) acoustic positioning system. At first, the relationship between the displacements on the ‘arc’ trajectory in directions of east and north, output by the LBL and DR systems, serves to judge the carrier direction and calibrate δ C . And then by compensating δ C , the displacement on the ‘linear’ trajectory is used to calibrate δ \\psi . Finally, a semi-physical simulation experiment is conducted to test and verify this calibration method to see how effective and accurate it is. Experimental results show that after calibration the residual error ratios of δ C and δ \\psi are 8.24% and 3.70% respectively. Therefore, online calibration of δ C and δ \\psi is realized effectively. What’s more, when the DR system is working alone in 400 s, this method reduces position error by up to 93.39%, from 18.91 m to 1.25 m.

  6. Identification of calibration and operating limits of a low-cost embedded system with MEMS accelerometer

    Science.gov (United States)

    D'Emilia, G.; Di Gasbarro, D.; Gaspari, A.; Natale, E.

    2017-08-01

    In this paper some aspects concerning the calibration uncertainty of three-axis low-cost accelerometers for possible use in diagnostics of civil buildings are considered, using a linear slide and a laser vibrometer as the reference. In order to analyse the principal and cross sensitivity and the offset of the sensor in dynamic conditions, the sensitivity matrix method has been used. Some considerations about the operating limits of a low-cost embedded system with MEMS accelerometer have been discussed, with reference to the calibration procedure. In particular, the effects of the non-constant sampling and of the achievable sampling rate, are studied with reference to the calibration uncertainty and to the capability of the calibration procedure to assess the best metrological performances of the system under test.

  7. SYS 2: Acoustic ENSBox A System of Self Calibrating Distributed Acoustic Arrays

    OpenAIRE

    Lewis Girod; Martin Lukac; Vlad Trifa; Deborah Estrin

    2006-01-01

    The Acoustic Embedded Networked Sensing Box, is a platform for prototyping rapid-deployable distributed acoustic sensing systems, particularly distributed source localization. Each ENSBox integrates an ARM processor running Linux and supports key facilities required for source localization: a sensor array, wireless network services, time synchronization, and precise self-calibration of array position and orientation. The ENSBoxs integrated high precision self-calibration facility sets it ap...

  8. A robust method for online stereo camera self-calibration in unmanned vehicle system

    Science.gov (United States)

    Zhao, Yu; Chihara, Nobuhiro; Guo, Tao; Kimura, Nobutaka

    2014-06-01

    Self-calibration is a fundamental technology used to estimate the relative posture of the cameras for environment recognition in unmanned system. We focused on the issue of recognition accuracy decrease caused by the vibration of platform and conducted this research to achieve on-line self-calibration using feature point's registration and robust estimation of fundamental matrix. Three key factors in this respect are needed to be improved. Firstly, the feature mismatching exists resulting in the decrease of estimation accuracy of relative posture. The second, the conventional estimation method cannot satisfy both the estimation speed and calibration accuracy at the same tame. The third, some system intrinsic noises also lead greatly to the deviation of estimation results. In order to improve the calibration accuracy, estimation speed and system robustness for the practical implementation, we discuss and analyze the algorithms to make improvements on the stereo camera system to achieve on-line self-calibration. Based on the epipolar geometry and 3D images parallax, two geometry constraints are proposed to make the corresponding feature points search performed in a small search-range resulting in the improvement of matching accuracy and searching speed. Then, two conventional estimation algorithms are analyzed and evaluated for estimation accuracy and robustness. The third, Rigorous posture calculation method is proposed with consideration of the relative posture deviation of each separated parts in the stereo camera system. Validation experiments were performed with the stereo camera mounted on the Pen-Tilt Unit for accurate rotation control and the evaluation shows that our proposed method is fast and of high accuracy with high robustness for on-line self-calibration algorithm. Thus, as the main contribution, we proposed methods to solve the on-line self-calibration fast and accurately, envision the possibility for practical implementation on unmanned system as

  9. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems

    Directory of Open Access Journals (Sweden)

    Jaehoon Jung

    2015-05-01

    Full Text Available The Simultaneous Localization and Mapping (SLAM technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs: one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system’s trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach.

  10. Study of the performance of stereoscopic panomorph systems calibrated with traditional pinhole model

    Science.gov (United States)

    Poulin-Girard, Anne-Sophie; Thibault, Simon; Laurendeau, Denis

    2016-06-01

    With their large field of view, anamorphosis, and areas of enhanced magnification, panomorph lenses are an interesting choice for navigation systems for mobile robotics in which knowledge of the surroundings is mandatory. However, panomorph lenses special characteristics can be challenging during the calibration process. This study focuses on the calibration of two panomorph stereoscopic systems with a model and technique developed for narrow-angle lenses, the "Camera Calibration Toolbox for MATLAB." In order to assess the performance of the systems, the mean reprojection error (MRE) related to the calibration and the reconstruction error of control points of an object of interest at various locations in the field of view are used. The calibrations were successful and exhibit MREs of less than one pixel in all cases. However, some poorly reconstructed control points illustrate that an acceptable MRE guarantees neither the quality of 3-D reconstruction nor its uniformity in the field of view. In addition, the nonuniformity in the 3-D reconstruction quality indicates that panomorph lenses require a more accurate estimation of the principal point (center of distortion) coordinates to improve the calibration and therefore the 3-D reconstruction.

  11. An efficient calibration method for SQUID measurement system using three orthogonal Helmholtz coils

    Science.gov (United States)

    Hua, Li; Shu-Lin, Zhang; Chao-Xiang, Zhang; Xiang-Yan, Kong; Xiao-Ming, Xie

    2016-06-01

    For a practical superconducting quantum interference device (SQUID) based measurement system, the Tesla/volt coefficient must be accurately calibrated. In this paper, we propose a highly efficient method of calibrating a SQUID magnetometer system using three orthogonal Helmholtz coils. The Tesla/volt coefficient is regarded as the magnitude of a vector pointing to the normal direction of the pickup coil. By applying magnetic fields through a three-dimensional Helmholtz coil, the Tesla/volt coefficient can be directly calculated from magnetometer responses to the three orthogonally applied magnetic fields. Calibration with alternating current (AC) field is normally used for better signal-to-noise ratio in noisy urban environments and the results are compared with the direct current (DC) calibration to avoid possible effects due to eddy current. In our experiment, a calibration relative error of about 6.89 × 10-4 is obtained, and the error is mainly caused by the non-orthogonality of three axes of the Helmholtz coils. The method does not need precise alignment of the magnetometer inside the Helmholtz coil. It can be used for the multichannel magnetometer system calibration effectively and accurately. Project supported by the “Strategic Priority Research Program (B)” of the Chinese Academy of Sciences (Grant No. XDB04020200) and the Shanghai Municipal Science and Technology Commission Project, China (Grant No. 15DZ1940902).

  12. Online calibration technique for LDV in SINS/LDV integrated navigation systems

    Science.gov (United States)

    Wang, Qi; Gao, Chunfeng; Wei, Guo; Long, Xingwu

    2017-05-01

    There are the scale factor error of LDV (laser Doppler velocimeter) and the misalignment between the SINS (Strapdown inertial navigation system) and the vehicle in a SINS/LDV integrated navigation system. In this paper, the effects of these errors on the attitude, velocity and position of dead reckoning are derived, and a new online calibration method aiming to calibrate the scale factor of LDV and the misalignment between the SINS and the vehicle for the integrated system is put forward. This method, which is utilize the velocity and position of the Global Position System (GPS) as references, use the velocity error and position error of dead reckoning to estimate these errors. Through simulation and experiment, the validity and feasibility of the method are verified. The results show that the scale factor and the misalignment can be calibrated with satisfying accuracy, and the related research can provide technical support for high precision navigation of SINS/LDV integrated navigation systems.

  13. Spectral phase-based automatic calibration scheme for swept source-based optical coherence tomography systems

    Science.gov (United States)

    Ratheesh, K. M.; Seah, L. K.; Murukeshan, V. M.

    2016-11-01

    The automatic calibration in Fourier-domain optical coherence tomography (FD-OCT) systems allows for high resolution imaging with precise depth ranging functionality in many complex imaging scenarios, such as microsurgery. However, the accuracy and speed of the existing automatic schemes are limited due to the functional approximations and iterative operations used in their procedures. In this paper, we present a new real-time automatic calibration scheme for swept source-based optical coherence tomography (SS-OCT) systems. The proposed automatic calibration can be performed during scanning operation and does not require an auxiliary interferometer for calibration signal generation and an additional channel for its acquisition. The proposed method makes use of the spectral component corresponding to the sample surface reflection as the calibration signal. The spectral phase function representing the non-linear sweeping characteristic of the frequency-swept laser source is determined from the calibration signal. The phase linearization with improved accuracy is achieved by normalization and rescaling of the obtained phase function. The fractional-time indices corresponding to the equidistantly spaced phase intervals are estimated directly from the resampling function and are used to resample the OCT signals. The proposed approach allows for precise calibration irrespective of the path length variation induced by the non-planar topography of the sample or galvo scanning. The conceived idea was illustrated using an in-house-developed SS-OCT system by considering the specular reflection from a mirror and other test samples. It was shown that the proposed method provides high-performance calibration in terms of axial resolution and sensitivity without increasing computational and hardware complexity.

  14. An investigation into factors affecting electron density calibration for a megavoltage cone-beam CT system.

    Science.gov (United States)

    Hughes, Jessica; Holloway, Lois C; Quinn, Alexandra; Fielding, Andrew

    2012-09-06

    There is a growing interest in the use of megavoltage cone-beam computed tomography (MV CBCT) data for radiotherapy treatment planning. To calculate accurate dose distributions, knowledge of the electron density (ED) of the tissues being irradiated is required. In the case of MV CBCT, it is necessary to determine a calibration-relating CT number to ED, utilizing the photon beam produced for MV CBCT. A number of different parameters can affect this calibration. This study was undertaken on the Siemens MV CBCT system, MVision, to evaluate the effect of the following parameters on the reconstructed CT pixel value to ED calibration: the number of monitor units (MUs) used (5, 8, 15 and 60 MUs), the image reconstruction filter (head and neck, and pelvis), reconstruction matrix size (256 by 256 and 512 by 512), and the addition of extra solid water surrounding the ED phantom. A Gammex electron density CT phantom containing EDs from 0.292 to 1.707 was imaged under each of these conditions. The linear relationship between MV CBCT pixel value and ED was demonstrated for all MU settings and over the range of EDs. Changes in MU number did not dramatically alter the MV CBCT ED calibration. The use of different reconstruction filters was found to affect the MV CBCT ED calibration, as was the addition of solid water surrounding the phantom. Dose distributions from treatment plans calculated with simulated image data from a 15 MU head and neck reconstruction filter MV CBCT image and a MV CBCT ED calibration curve from the image data parameters and a 15 MU pelvis reconstruction filter showed small and clinically insignificant differences. Thus, the use of a single MV CBCT ED calibration curve is unlikely to result in any clinical differences. However, to ensure minimal uncertainties in dose reporting, MV CBCT ED calibration measurements could be carried out using parameter-specific calibration measurements.

  15. Improving Photometric Calibration of Meteor Video Camera Systems

    Science.gov (United States)

    Ehlert, Steven; Kingery, Aaron; Suggs, Robert

    2016-01-01

    We present the results of new calibration tests performed by the NASA Meteoroid Environment Oce (MEO) designed to help quantify and minimize systematic uncertainties in meteor photometry from video camera observations. These systematic uncertainties can be categorized by two main sources: an imperfect understanding of the linearity correction for the MEO's Watec 902H2 Ultimate video cameras and uncertainties in meteor magnitudes arising from transformations between the Watec camera's Sony EX-View HAD bandpass and the bandpasses used to determine reference star magnitudes. To address the rst point, we have measured the linearity response of the MEO's standard meteor video cameras using two independent laboratory tests on eight cameras. Our empirically determined linearity correction is critical for performing accurate photometry at low camera intensity levels. With regards to the second point, we have calculated synthetic magnitudes in the EX bandpass for reference stars. These synthetic magnitudes enable direct calculations of the meteor's photometric ux within the camera band-pass without requiring any assumptions of its spectral energy distribution. Systematic uncertainties in the synthetic magnitudes of individual reference stars are estimated at 0:20 mag, and are limited by the available spectral information in the reference catalogs. These two improvements allow for zero-points accurate to 0:05 ?? 0:10 mag in both ltered and un ltered camera observations with no evidence for lingering systematics.

  16. Transponder-aided joint calibration and synchronization compensation for distributed radar systems.

    Directory of Open Access Journals (Sweden)

    Wen-Qin Wang

    Full Text Available High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF. The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results.

  17. Transponder-aided joint calibration and synchronization compensation for distributed radar systems.

    Science.gov (United States)

    Wang, Wen-Qin

    2015-01-01

    High-precision radiometric calibration and synchronization compensation must be provided for distributed radar system due to separate transmitters and receivers. This paper proposes a transponder-aided joint radiometric calibration, motion compensation and synchronization for distributed radar remote sensing. As the transponder signal can be separated from the normal radar returns, it is used to calibrate the distributed radar for radiometry. Meanwhile, the distributed radar motion compensation and synchronization compensation algorithms are presented by utilizing the transponder signals. This method requires no hardware modifications to both the normal radar transmitter and receiver and no change to the operating pulse repetition frequency (PRF). The distributed radar radiometric calibration and synchronization compensation require only one transponder, but the motion compensation requires six transponders because there are six independent variables in the distributed radar geometry. Furthermore, a maximum likelihood method is used to estimate the transponder signal parameters. The proposed methods are verified by simulation results.

  18. A Visual Servoing-Based Method for ProCam Systems Calibration

    Directory of Open Access Journals (Sweden)

    Jeremie Mosnier

    2013-10-01

    Full Text Available Projector-camera systems are currently used in a wide field of applications, such as 3D reconstruction and augmented reality, and can provide accurate measurements, depending on the configuration and calibration. Frequently, the calibration task is divided into two steps: camera calibration followed by projector calibration. The latter still poses certain problems that are not easy to solve, such as the difficulty in obtaining a set of 2D–3D points to compute the projection matrix between the projector and the world. Existing methods are either not sufficiently accurate or not flexible. We propose an easy and automatic method to calibrate such systems that consists in projecting a calibration pattern and superimposing it automatically on a known printed pattern. The projected pattern is provided by a virtual camera observing a virtual pattern in an OpenGL model. The projector displays what the virtual camera visualizes. Thus, the projected pattern can be controlled and superimposed on the printed one with the aid of visual servoing. Our experimental results compare favorably with those of other methods considering both usability and accuracy.

  19. Calibration of the Accuscan II In Vivo System for Whole Body Counting

    Energy Technology Data Exchange (ETDEWEB)

    Orval R. Perry; David L. Georgeson

    2011-08-01

    This report describes the April 2011 calibration of the Accuscan II HpGe In Vivo system for whole body counting. The source used for the calibration was a NIST traceable BOMAB manufactured by DOE as INL2006 BOMAB containing Eu-154, Eu-155, Eu-152, Sb-125 and Y-88 with energies from 27 keV to 1836 keV with a reference date of 11/29/2006. The actual usable energy range was 86.5 keV to 1597 keV on 4/21/2011. The BOMAB was constructed inside the Accuscan II counting 'tub' in the order of legs, thighs, abdomen, thorax/arms, neck, and head. Each piece was taped to the backwall of the counter. The arms were taped to the thorax. The phantom was constructed between the v-ridges on the backwall of the Accuscan II counter. The energy and efficiency calibrations were performed using the INL2006 BOMAB. The calibrations were performed with the detectors in the scanning mode. This report includes an overview introduction and records for the energy/FWHM and efficiency calibration including performance verification and validation counting. The Accuscan II system was successfully calibrated for whole body counting and verified in accordance with ANSI/HPS N13.30-1996 criteria.

  20. A visual servoing-based method for ProCam systems calibration.

    Science.gov (United States)

    Berry, Francois; Aider, Omar Ait; Mosnier, Jeremie

    2013-10-01

    Projector-camera systems are currently used in a wide field of applications, such as 3D reconstruction and augmented reality, and can provide accurate measurements, depending on the configuration and calibration. Frequently, the calibration task is divided into two steps: camera calibration followed by projector calibration. The latter still poses certain problems that are not easy to solve, such as the difficulty in obtaining a set of 2D-3D points to compute the projection matrix between the projector and the world. Existing methods are either not sufficiently accurate or not flexible. We propose an easy and automatic method to calibrate such systems that consists in projecting a calibration pattern and superimposing it automatically on a known printed pattern. The projected pattern is provided by a virtual camera observing a virtual pattern in an OpenGL model. The projector displays what the virtual camera visualizes. Thus, the projected pattern can be controlled and superimposed on the printed one with the aid of visual servoing. Our experimental results compare favorably with those of other methods considering both usability and accuracy.

  1. A Flexile and High Precision Calibration Method for Binocular Structured Light Scanning System

    Directory of Open Access Journals (Sweden)

    Jianying Yuan

    2014-01-01

    Full Text Available 3D (three-dimensional structured light scanning system is widely used in the field of reverse engineering, quality inspection, and so forth. Camera calibration is the key for scanning precision. Currently, 2D (two-dimensional or 3D fine processed calibration reference object is usually applied for high calibration precision, which is difficult to operate and the cost is high. In this paper, a novel calibration method is proposed with a scale bar and some artificial coded targets placed randomly in the measuring volume. The principle of the proposed method is based on hierarchical self-calibration and bundle adjustment. We get initial intrinsic parameters from images. Initial extrinsic parameters in projective space are estimated with the method of factorization and then upgraded to Euclidean space with orthogonality of rotation matrix and rank 3 of the absolute quadric as constraint. Last, all camera parameters are refined through bundle adjustment. Real experiments show that the proposed method is robust, and has the same precision level as the result using delicate artificial reference object, but the hardware cost is very low compared with the current calibration method used in 3D structured light scanning system.

  2. Optical System Error Analysis and Calibration Method of High-Accuracy Star Trackers

    Directory of Open Access Journals (Sweden)

    Zheng You

    2013-04-01

    Full Text Available The star tracker is a high-accuracy attitude measurement device widely used in spacecraft. Its performance depends largely on the precision of the optical system parameters. Therefore, the analysis of the optical system parameter errors and a precise calibration model are crucial to the accuracy of the star tracker. Research in this field is relatively lacking a systematic and universal analysis up to now. This paper proposes in detail an approach for the synthetic error analysis of the star tracker, without the complicated theoretical derivation. This approach can determine the error propagation relationship of the star tracker, and can build intuitively and systematically an error model. The analysis results can be used as a foundation and a guide for the optical design, calibration, and compensation of the star tracker. A calibration experiment is designed and conducted. Excellent calibration results are achieved based on the calibration model. To summarize, the error analysis approach and the calibration method are proved to be adequate and precise, and could provide an important guarantee for the design, manufacture, and measurement of high-accuracy star trackers.

  3. Review of AO calibrations, or how to best educate your AO system

    Science.gov (United States)

    Kolb, Johann

    2016-07-01

    If the Real-Time Computer is the heart of an AO system, the Wavefront Sensor (WFS) its eyes, the Deformable Mirror (DM) its hands and the control strategy its nervous system, the sum of all those parts is made into a harmonious entity thanks to calibrations. This paper does not have the ambition to provide an overview of all the currently existing calibration strategies, but rather to focus on a few challenging problems and their recent evolution in the era of adaptive telescopes, mostly based on the experience of ESO's Adaptive Optics Instruments in general and the AO Facility in particular. Single most important calibration in post-focal AO system, the recording of the Interaction Matrix (IM) between WFS and DM has since long evolved to use fast modulation techniques, has shown to be feasible on-sky and is now almost free from measurements thanks to its pseudo-synthetic generation, quasi-mandatory solution in an adaptive telescope. Pseudo- because it requires an unprecedented knowledge of the components' characteristics, especially the WFS, DM and the optical registration between the two. Bigger telescopes and the use of Laser Guide Stars (LGS) also mean that the properties of the system will change in time and thus need to be constantly updated thanks to online diagnosis tools for spot size measurement, atmosphere monitoring, Wavefront Sensing and control optimization. New loops come into play like the one to minimize LGS Jitter and the one taking over the telescope active optics by means of offloading the DM low orders, and they all require calibration. More calibration means more time and one has to carefully balance the calibrations that require precious telescope night time, day time or for the best, no telescope time at all. Their importance sometimes underestimated, calibrations have repeatedly shown to be a vital part in the optimum functioning of present and future AO systems.

  4. Motion compensation in a tomographic ultrasound imaging system: Toward volumetric scans of a limb for prosthetic socket design.

    Science.gov (United States)

    Ranger, Bryan J; Feigin, Micha; Pestrov, Nikita; Zhang, Xiang; Lempitsky, Victor; Herr, Hugh M; Anthony, Brian W

    2015-08-01

    Current methods of prosthetic socket fabrication remain subjective and ineffective at creating an interface to the human body that is both comfortable and functional. Though there has been recent success using methods like magnetic resonance imaging and biomechanical modeling, a low-cost, streamlined, and repeatable process has not been fully demonstrated. Medical ultrasonography, which has significant potential to expand its clinical applications, is being pursued to acquire data that may quantify and improve the design process and fabrication of prosthetic sockets. This paper presents a new multi-modal imaging approach for acquiring volumetric images of a human limb, specifically focusing on how motion of the limb is compensated for using optical imagery.

  5. Study on Calibration System for Electronic Transformers Based on High-Accuracy PCI Card

    Directory of Open Access Journals (Sweden)

    Mingzhu Zhang

    2013-03-01

    Full Text Available With preliminary applying of Electronic Transformer (ET based on IEC 61850 standards in power grid, the calibrations of tested transformers have attracted extensive research attention. This study proposes a novel Calibration System of ET (CSET based on high-accuracy card. Data acquisition of ET and Standard Trans-former (ST is gotten by optic Ethernet and PCI-4462 data acquisition card, respectively. Meanwhile, the synchronized sampling between ET and ST is completed on the optic/electronic pulse signal of PCI synchronization card. The signals processing and human interface are realized by Labview software. The system proposed in the study is feasible for calibrating Electronic Voltage/Current Transformers (EVT/ECT of different voltage classes. System tests show that the precision of the system can get to 0.2°.

  6. Study on Calibration System for Electronic Transformers Based on High-Accuracy PCI Card

    Directory of Open Access Journals (Sweden)

    Mingzhu Zhang

    2013-05-01

    Full Text Available With preliminary applying of Electronic Transformer (ET based on IEC 61850 standards in power grid, the calibration of tested transformers has attracted extensive research attention. This study proposes a novel Calibration System of ET (CSET based on high-accuracy card. Data acquisition of ET and standard trans-former (ST is gotten by optic Ethernet and PCI-4462 data acquisition card, respectively. Meanwhile, the synchronized sampling between ET and ST is completed on the optic/electronic pulse signal of PCI synchronization card. The signals processing and human interface are realized by Lab view software. The system proposed in the study is feasible for calibrating Electronic Voltage/Current Transformers (EVT/ECT of different voltage classes. System tests show that the precision of the system can get to 0.2°.

  7. The Data Acquisition and Calibration System for the ATLAS Semiconductor Tracker

    CERN Document Server

    Abdesselam, A; Barr, A J; Bell, P; Bernabeu, J; Butterworth, J M; Carter, J R; Carter, A A; Charles, E; Clark, A; Colijn, A P; Costa, M J; Dalmau, J M; Demirkoz, B; Dervan, P J; Donega, M; D'Onifrio, M; Escobar, C; Fasching, D; Ferguson, D P S; Ferrari, P; Ferrère, D; Fuster, J; Gallop, B; García, C; González, S; González-Sevilla, S; Goodrick, M J; Gorisek, A; Greenall, A; Grillo, A A; Hessey, N P; Hill, J C; Jackson, J N; Jared, R C; Johannson, P D C; de Jong, P; Joseph, J; Lacasta, C; Lane, J B; Lester, C G; Limper, M; Lindsay, S W; McKay, R L; Magrath, C A; Mangin-Brinet, M; Martí i García, S; Mellado, B; Meyer, W T; Mikulec, B; Minano, M; Mitsou, V A; Moorhead, G; Morrissey, M; Paganis, E; Palmer, M J; Parker, M A; Pernegger, H; Phillips, A; Phillips, P W; Postranecky, M; Robichaud-Véronneau, A; Robinson, D; Roe, S; Sandaker, H; Sciacca, F; Sfyrla, A; Stanecka, E; Stapnes, S; Stradling, A; Tyndel, M; Tricoli, A; Vickey, T; Vossebeld, J H; Warren, M R M; Weidberg, A R; Wells, P S; Wu, S L

    2008-01-01

    The SemiConductor Tracker (SCT) data acquisition (DAQ) system will calibrate, configure, and control the approximately six million front-end channels of the ATLAS silicon strip detector. It will provide a synchronized bunch-crossing clock to the front-end modules, communicate first-level triggers to the front-end chips, and transfer information about hit strips to the ATLAS high-level trigger system. The system has been used extensively for calibration and quality assurance during SCT barrel and endcap assembly and for performance confirmation tests after transport of the barrels and endcaps to CERN. Operating in data-taking mode, the DAQ has recorded nearly twenty million synchronously-triggered events during commissioning tests including almost a million cosmic ray triggered events. In this paper we describe the components of the data acquisition system, discuss its operation in calibration and data-taking modes and present some detector performance results from these tests.

  8. Aspects of the optical system relevant for the KM3NeT timing calibration

    Directory of Open Access Journals (Sweden)

    Kieft Gerard

    2016-01-01

    Full Text Available KM3NeT is a future research infrastructure in the Mediterranean Sea housing the large Cherenkov telescope arrays of optical modules for neutrino detection. The detector control and data transmission system is based on fibre optical technology. For timing calibration of the detector signals the optical system is used to send and fan-out an onshore clock signal, derived from a GPS receiver, to all optical modules in the deep sea. The optical modules use this clock signal to time stamp the light pulses detected by the photomultipliers inside the modules. The delay time between the GPS clock on shore and the clock in each optical module is measured with sub-nanosecond precision using a White Rabbit based timing calibration system. The aspects of the optical system relevant for the timing calibration and the quantification of their effect will be presented.

  9. Development of an XYZ Digital Camera with Embedded Color Calibration System for Accurate Color Acquisition

    Science.gov (United States)

    Kretkowski, Maciej; Jablonski, Ryszard; Shimodaira, Yoshifumi

    Acquisition of accurate colors is important in the modern era of widespread exchange of electronic multimedia. The variety of device-dependent color spaces causes troubles with accurate color reproduction. In this paper we present the outlines of accomplished digital camera system with device-independent output formed from tristimulus XYZ values. The outstanding accuracy and fidelity of acquired color is achieved in our system by employing an embedded color calibration system based on emissive device generating reference calibration colors with user-defined spectral distribution and chromaticity coordinates. The system was tested by calibrating the camera using 24 reference colors spectrally reproduced from 24 color patches of the Macbeth Chart. The average color difference (CIEDE2000) has been found to be ΔE =0.83, which is an outstanding result compared to commercially available digital cameras.

  10. High precision, low disturbance calibration of the High Voltage system of the CMS Barrel Electromagnetic Calorimeter

    CERN Document Server

    Marzocchi, Badder

    2017-01-01

    The CMS Electromagnetic Calorimeter is made of scintillating lead tungstate crystals, using avalanche photodiodes (APD) as photo-detectors in the barrel part. The high voltage system, consisting of 1224 channels, biases groups of 50 APD pairs, each at a voltage of about 380 V. The APD gain dependence on the voltage is 3pct/V. A stability of better than 60 mV is needed to have negligible impact on the calorimeter energy resolution. Until 2015 manual calibrations were performed yearly. A new calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision. The system is discussed in detail and first operational experience is presented.

  11. 光电综合标校系统光轴平行度标校方法%Optical Parallelism Calibration Method of Photoelectric Integrated Calibration System

    Institute of Scientific and Technical Information of China (English)

    郑均杰; 张镭; 李杰然

    2011-01-01

    针对光电综合标校系统的功能组成及标校原理,提出了标校靶标的设计及标校方法,并利用感光相纸对激光光斑进行聚焦采集,实现了对电视/红外/激光三者光轴一致性的标校,检测结果验证了该标校靶标及标校方法的可行性和有效性。%Aiming at the function component and calibration principle of photoelectric integrated calibration system,this paper presents the design and calibration method of calibration drone,and realizes the calibration to the axes consistency of television,infrared and laser by using the photographic papers to focus and collect laser spots.The detection result proves the feasibility and usefulness of the calibration drone and the calibration method.

  12. Calibration of the Failed-Fuel-Element Detection Systems in the Aagesta Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O.

    1966-06-15

    Results from a calibration of the systems for detection of fuel element ruptures in the Aagesta reactor are presented. The calibration was carried out by means of foils of zirconium-uranium alloy which were placed in a special fuel assembly. The release of fission products from these foils is due mainly to recoil and can be accurately calculated. Before the foils were used in the reactor their corrosion behaviour in high temperature water was investigated. The results obtained with the precipitator systems for bulk detection and localization are in good agreement with the expected performance. The sensitivity of these systems was found to be high enough for detection and localization of small defects of pin-hole type ({nu} = 10{sup -8}/s ). The general performance of the systems was satisfactory during the calibration tests, although a few adjustments are desirable. A bulk detecting system for monitoring of activities in the moderator, in which the {gamma}-radiation from coolant samples is measured directly after an ion exchanger, showed lower sensitivity than expected from calculations. It seems that the sensitivity of the latter system has to be improved to admit the detection of small defects. In the ion exchanger system, and to some extent in the precipitator systems, the background from A{sup 41} in the coolant limits the sensitivity. The calibration technique utilized seems to be of great advantage when investigating the performance of failed-fuel-element detection systems.

  13. A laser diode based system for calibration of fast time-of-flight detectors

    Science.gov (United States)

    Bertoni, R.; Bonesini, M.; de Bari, A.; Rossella, M.

    2016-05-01

    A system based on commercially available items, such as a laser diode, emitting in the visible range ~ 400 nm, and multimode fiber patches, fused fiber splitters and optical switches may be assembled, for time calibration of multi-channels time-of-flight (TOF) detectors with photomultipliers' (PMTs') readout. As available laser diode sources have unfortunately limited peak power, the main experimental problem is the tight light power budget of such a system. In addition, while the technology for fused fiber splitters is common in the Telecom wavelength range (λ ~ 850, 1300-1500 nm), it is not easily available in the visible one. Therefore, extensive laboratory tests had to be done on purpose, to qualify the used optical components, and a full scale timing calibration prototype was built. Obtained results show that with such a system, a calibration resolution (σ) in the range 20-30 ps may be within reach. Therefore, fast multi-channels TOF detectors, with timing resolutions in the range 50-100 ps, may be easily calibrated in time. Results on tested optical components may be of interest also for time calibration of different light detection systems based on PMTs, as the ones used for detection of the vacuum ultraviolet scintillation light emitted by ionizing particles in large LAr TPCs.

  14. The Calibration Algorithm of a 3D Color Measurement System based on the Line Feature

    Directory of Open Access Journals (Sweden)

    Ganhua Li

    2009-10-01

    Full Text Available This paper describes a novel 3 dimensional color measurement system. After 3 kinds of geometrical features are analyzed, the line features were selected. A calibration board with right-angled triangle outline was designed to improve the calibration precision. For this system, two algorithms are presented. One is the calibration algorithm between 2 dimensional laser range finder (2D LRF, while the other is for 2D LRF and the color camera. The result parameters were obtained through solving the constrain equations by the correspond data between the 2D LRF and other two sensors. The 3D color reconstruction experiments of real data prove the effectiveness and the efficient of the system and the algorithms.

  15. IRFM Temperature Calibrations for the Vilnius, Geneva, RI(C) and DDO Photometric Systems

    CERN Document Server

    Melendez, J; Melendez, Jorge; Ramirez, Ivan

    2003-01-01

    We have used the infrared flux method (IRFM) temperatures of a large sample of late type dwarfs given by Alonso et al. (1996a) to calibrate empirically the relations Teff = f (colour, [Fe/H]) for the Vilnius, Geneva, RI(C) and DDO photometric systems. The resulting temperature scale and intrinsic colour-colour diagrams for these systems are also obtained. From this scale, the solar colours are derived and compared with those of the solar twin 18 Sco. Since our work is based on the same Teff and [Fe/H] values used by Alonso et al. (1996b) to calibrate other colours, we now have an homogeneous calibration for a large set of photometric systems.

  16. Shading correction and calibration in bacterial fluorescence measurement by image processing system

    NARCIS (Netherlands)

    Wilkinson, M.H.F.

    1994-01-01

    An image processing system with applications in bacterial (immuno-)fluorescence measurement has been developed. To reach quantitative results, correction for non-uniformities in system sensitivity, both as a function of time (calibration for drifts) and as a function of image coordinates (shading co

  17. The Magnetic Distortion Calibration System of the LHCb RICH1 Detector

    CERN Document Server

    Borgia, A; Contu, A; D'Ambrosio, C; Frei, C; Harnew, N; John, M; Lefeuvre, G; Mountain, R; Stone, S; Websdale, D; Xing, F

    2014-01-01

    The LHCb RICH1 detector uses hybrid photon detectors (HPDs) as its optical sensors. A calibration system has been constructed to provide corrections for distortions that are primarily due to external magnetic fields. We describe here the system design, construction, operation and performance.

  18. Shading correction and calibration in bacterial fluorescence measurement by image processing system

    NARCIS (Netherlands)

    Wilkinson, M.H.F.

    1994-01-01

    An image processing system with applications in bacterial (immuno-)fluorescence measurement has been developed. To reach quantitative results, correction for non-uniformities in system sensitivity, both as a function of time (calibration for drifts) and as a function of image coordinates (shading co

  19. Modelling and calibration of the laser beam-scanning triangulation measurement system

    NARCIS (Netherlands)

    Wang, Guoyu; Zheng, Bing; Li, Xin; Houkes, Z.; Regtien, P.P.L.

    2002-01-01

    We present an approach of modelling and calibration of an active laser beam-scanning triangulation measurement system. The system works with the pattern of two-dimensional beam-scanning illumination and one-dimensional slit-scanning detection with a photo-multiplier tube instead of a CCD camera. By

  20. Pyrgeometer Calibration for DOE-Atmospheric System Research Program Using NREL Method (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Reda, I.; Stoffel, T.

    2010-03-15

    Presented at the DOE-Atmospheric System Research Program, Science Team Meeting, 15-19 March 2010, Bethesda, Maryland. The presentation: Pyrgeometer Calibration for DOE-Atmospheric System Research program using NREL Method - was presented by Ibrahim Reda and Tom Stoffel on March 15, 2010 at the 2010 ASR Science Team Meeting. March 15-19, 2010, Bethesda, Maryland.

  1. Radioactive source control and electronics for the ATLAS tile calorimeter cesium calibration system

    CERN Document Server

    Shalanda, N A; Kopikov, S; Shalimov, A; Soldatov, M; Solodkov, A; Starchenko, E A

    2003-01-01

    A system using a radioactive /sup 137/Cs source to calibrate and monitor the Hadron Calorimeter (TileCal) of the ATLAS experiment at the LHC is described. The system includes a set of sensors to monitor the position of the source which moves via hydraulic propulsion. The design of the sensors, the corresponding electronic modules and their performance are detailed. (6 refs).

  2. Modelling and calibration of the laser beam-scanning triangulation measurement system

    NARCIS (Netherlands)

    Wang, G.Y.; Zheng, Bing; Li, Xin; Houkes, Z.; Regtien, Paulus P.L.

    2002-01-01

    We present an approach of modelling and calibration of an active laser beam-scanning triangulation measurement system. The system works with the pattern of two-dimensional beam-scanning illumination and one-dimensional slit-scanning detection with a photo-multiplier tube instead of a CCD camera. By

  3. Hybrid dynamic radioactive particle tracking (RPT) calibration technique for multiphase flow systems

    Science.gov (United States)

    Khane, Vaibhav; Al-Dahhan, Muthanna H.

    2017-04-01

    The radioactive particle tracking (RPT) technique has been utilized to measure three-dimensional hydrodynamic parameters for multiphase flow systems. An analytical solution to the inverse problem of the RPT technique, i.e. finding the instantaneous tracer positions based upon instantaneous counts received in the detectors, is not possible. Therefore, a calibration to obtain a counts-distance map is needed. There are major shortcomings in the conventional RPT calibration method due to which it has limited applicability in practical applications. In this work, the design and development of a novel dynamic RPT calibration technique are carried out to overcome the shortcomings of the conventional RPT calibration method. The dynamic RPT calibration technique has been implemented around a test reactor with 1foot in diameter and 1 foot in height using Cobalt-60 as an isotopes tracer particle. Two sets of experiments have been carried out to test the capability of novel dynamic RPT calibration. In the first set of experiments, a manual calibration apparatus has been used to hold a tracer particle at known static locations. In the second set of experiments, the tracer particle was moved vertically downwards along a straight line path in a controlled manner. The obtained reconstruction results about the tracer particle position were compared with the actual known position and the reconstruction errors were estimated. The obtained results revealed that the dynamic RPT calibration technique is capable of identifying tracer particle positions with a reconstruction error between 1 to 5.9 mm for the conditions studied which could be improved depending on various factors outlined here.

  4. Traceable Pyrgeometer Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, Mike; Kutchenreiter, Mark; Reda, Ibrahim; Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Newman, Martina

    2016-05-02

    This poster presents the development, implementation, and operation of the Broadband Outdoor Radiometer Calibrations (BORCAL) Longwave (LW) system at the Southern Great Plains Radiometric Calibration Facility for the calibration of pyrgeometers that provide traceability to the World Infrared Standard Group.

  5. Traceable Pyrgeometer Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, Mike; Kutchenreiter, Mark; Reda, Ibrahim; Habte, Aron; Sengupta, Manajit; Andreas, Afshin; Newman, Martina

    2016-05-02

    This poster presents the development, implementation, and operation of the Broadband Outdoor Radiometer Calibrations (BORCAL) Longwave (LW) system at the Southern Great Plains Radiometric Calibration Facility for the calibration of pyrgeometers that provide traceability to the World Infrared Standard Group.

  6. MO-DE-210-06: Development of a Supercompounded 3D Volumetric Ultrasound Image Guidance System for Prone Accelerated Partial Breast Irradiation (APBI)

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, T; Hrycushko, B; Zhao, B; Jiang, S; Gu, X [UT Southwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: For early-stage breast cancer, accelerated partial breast irradiation (APBI) is a cost-effective breast-conserving treatment. Irradiation in a prone position can mitigate respiratory induced breast movement and achieve maximal sparing of heart and lung tissues. However, accurate dose delivery is challenging due to breast deformation and lumpectomy cavity shrinkage. We propose a 3D volumetric ultrasound (US) image guidance system for accurate prone APBI Methods: The designed system, set beneath the prone breast board, consists of a water container, an US scanner, and a two-layer breast immobilization cup. The outer layer of the breast cup forms the inner wall of water container while the inner layer is attached to patient breast directly to immobilization. The US transducer scans is attached to the outer-layer of breast cup at the dent of water container. Rotational US scans in a transverse plane are achieved by simultaneously rotating water container and transducer, and multiple transverse scanning forms a 3D scan. A supercompounding-technique-based volumetric US reconstruction algorithm is developed for 3D image reconstruction. The performance of the designed system is evaluated with two custom-made gelatin phantoms containing several cylindrical inserts filled in with water (11% reflection coefficient between materials). One phantom is designed for positioning evaluation while the other is for scaling assessment. Results: In the positioning evaluation phantom, the central distances between the inserts are 15, 20, 30 and 40 mm. The distances on reconstructed images differ by −0.19, −0.65, −0.11 and −1.67 mm, respectively. In the scaling evaluation phantom, inserts are 12.7, 19.05, 25.40 and 31.75 mm in diameter. Measured inserts’ sizes on images differed by 0.23, 0.19, −0.1 and 0.22 mm, respectively. Conclusion: The phantom evaluation results show that the developed 3D volumetric US system can accurately localize target position and determine

  7. Development of a New Low-Cost Indoor Mapping System - System Design, System Calibration and First Results

    Science.gov (United States)

    Kersten, T. P.; Stallmann, D.; Tschirschwitz, F.

    2016-06-01

    For mapping of building interiors various 2D and 3D indoor surveying systems are available today. These systems essentially differ from each other by price and accuracy as well as by the effort required for fieldwork and post-processing. The Laboratory for Photogrammetry & Laser Scanning of HafenCity University (HCU) Hamburg has developed, as part of an industrial project, a lowcost indoor mapping system, which enables systematic inventory mapping of interior facilities with low staffing requirements and reduced, measurable expenditure of time and effort. The modelling and evaluation of the recorded data take place later in the office. The indoor mapping system of HCU Hamburg consists of the following components: laser range finder, panorama head (pan-tilt-unit), single-board computer (Raspberry Pi) with digital camera and battery power supply. The camera is pre-calibrated in a photogrammetric test field under laboratory conditions. However, remaining systematic image errors are corrected simultaneously within the generation of the panorama image. Due to cost reasons the camera and laser range finder are not coaxially arranged on the panorama head. Therefore, eccentricity and alignment of the laser range finder against the camera must be determined in a system calibration. For the verification of the system accuracy and the system calibration, the laser points were determined from measurements with total stations. The differences to the reference were 4-5mm for individual coordinates.

  8. Self-calibration of a cone-beam micro-CT system

    Energy Technology Data Exchange (ETDEWEB)

    Patel, V.; Chityala, R. N.; Hoffmann, K. R.; Ionita, C. N.; Bednarek, D. R.; Rudin, S. [Toshiba Stroke Research Center, Department of Physics, State University of New York at Buffalo, Buffalo, New York 14214 (United States); The Supercomputing Institute for Advanced Computational Research, University of Minnesota at Twin Cities, Minneapolis, Minnesota 55455 (United States); Toshiba Stroke Research Center, Department of Neurosurgery, Department of Physics, Department of Physiology and Biophysics, Department of Mechanical and Aerospace Engineering, and Department of Computer Science and Engineering, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Neurosurgery, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Radiology, Department of Neurosurgery, Department of Physics, and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States); Toshiba Stroke Research Center, Department of Radiology, Department of Neurosurgery, Department of Physiology and Biophysics, Department of Mechanical and Aerospace Engineering, and Department of Electrical Engineering, State University of New York at Buffalo, Buffalo, New York 14214 (United States)

    2009-01-15

    Use of cone-beam computed tomography (CBCT) is becoming more frequent. For proper reconstruction, the geometry of the CBCT systems must be known. While the system can be designed to reduce errors in the geometry, calibration measurements must still be performed and corrections applied. Investigators have proposed techniques using calibration objects for system calibration. In this study, the authors present methods to calibrate a rotary-stage CB micro-CT (CB{mu}CT) system using only the images acquired of the object to be reconstructed, i.e., without the use of calibration objects. Projection images are acquired using a CB{mu}CT system constructed in the authors' laboratories. Dark- and flat-field corrections are performed. Exposure variations are detected and quantified using analysis of image regions with an unobstructed view of the x-ray source. Translations that occur during the acquisition in the horizontal direction are detected, quantified, and corrected based on sinogram analysis. The axis of rotation is determined using registration of antiposed projection images. These techniques were evaluated using data obtained with calibration objects and phantoms. The physical geometric axis of rotation is determined and aligned with the rotational axis (assumed to be the center of the detector plane) used in the reconstruction process. The parameters describing this axis agree to within 0.1 mm and 0.3 deg with those determined using other techniques. Blurring due to residual calibration errors has a point-spread function in the reconstructed planes with a full-width-at-half-maximum of less than 125 {mu}m in a tangential direction and essentially zero in the radial direction for the rotating object. The authors have used this approach on over 100 acquisitions over the past 2 years and have regularly obtained high-quality reconstructions, i.e., without artifacts and no detectable blurring of the reconstructed objects. This self-calibrating approach not only

  9. Upgrade of the Laser Calibration System for the ATLAS Hadronic Calorimeter TileCal

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00352208

    2016-01-01

    We present in this contribution the new system for laser calibration of the ATLAS hadronic calorimeter TileCal. The laser system is a part of the three stage calibration apparatus designed to compute the calibration constants of the individual cells of TileCal. The laser system is mainly used to correct for short term (one month) drifts of the readout of the individual cells. A sub-percent accuracy in the control of the calibration constants is required to keep the systematics effects introduced by relative cell miscalibration below the irreducible systematics in determining the parameters of the reconstructed hadronic jets. To achieve this goal in the LHC Run 2 conditions, a new laser system was designed. The architecture of the system is described with details on the new optical line used to distribute laser pulses in each individual detector module and on the new electronics used to drive the laser, to readout the system optical monitors and to interface the system with the Atlas readout, trigger, and slow...

  10. Upgrade of the Laser Calibration System for the ATLAS Hadronic Calorimeter TileCal

    CERN Document Server

    Van Woerden, Marius Cornelis; The ATLAS collaboration

    2015-01-01

    We present in this contribution the new system for laser calibration of the ATLAS hadronic calorimeter TileCal. The laser system is a part of the three stage calibration apparatus designed to compute the calibration constants of the individual cells of TileCal. The laser system is mainly used to correct for short term (one month) drifts of the readout of the individual cells. A sub-percent accuracy in the control of the calibration constants is required to keep the systematics effects introduced by relative cell miscalibration below the irreducible systematics in determining the parameters of the reconstructed hadronic jets. To achieve this goal in the LHC run II conditions, a new laser system was designed. The architecture of the system is described with details on the new optical line used to distribute laser pulses in each individual detector module and on the new electronics used to drive the laser, to readout the system optical monitors and to interface the system with the Atlas readout, trigger, and slo...

  11. High precision, low disturbance calibration of the High Voltage system of the CMS Barrel Electromagnetic Calorimeter

    CERN Document Server

    Fasanella, Giuseppe

    2016-01-01

    The CMS Electromagnetic Calorimeter utilizes scintillating lead tungstate crystals, with avalanche photodiodes (APD) as photo-detectors in the barrel part. 1224 HV channels bias groups of 50 APD pairs, each at a voltage of about 380 V. The APD gain dependence on the voltage is 3pct/V. A stability of better than 60 mV is needed to have negligible impact on the calorimeter energy resolution. Until 2015 manual calibrations were performed yearly. A new calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision. The system is discussed in detail and first operational experience is presented.

  12. High precision, low disturbance calibration system for the CMS Barrel Electromagnetic Calorimeter High Voltage apparatus

    Science.gov (United States)

    Fasanella, G.

    2017-01-01

    The CMS Electromagnetic Calorimeter utilizes scintillation lead tungstate crystals, with avalanche photodiodes (APD) as photo-detectors in the barrel part. 1224 HV channels bias groups of 50 APD pairs, each at a voltage of about 380 V. The APD gain dependence on the voltage is 3%/V. A stability of better than 60 mV is needed to have negligible impact on the calorimeter energy resolution. Until 2015 manual calibrations were performed yearly. A new calibration system was deployed recently, which satisfies the requirement of low disturbance and high precision. The system is discussed in detail and first operational experience is presented.

  13. Calibration Issues and Operating System Requirements for Electron-Probe Microanalysis

    Science.gov (United States)

    Carpenter, P.

    2006-01-01

    Instrument purchase requirements and dialogue with manufacturers have established hardware parameters for alignment, stability, and reproducibility, which have helped improve the precision and accuracy of electron microprobe analysis (EPMA). The development of correction algorithms and the accurate solution to quantitative analysis problems requires the minimization of systematic errors and relies on internally consistent data sets. Improved hardware and computer systems have resulted in better automation of vacuum systems, stage and wavelength-dispersive spectrometer (WDS) mechanisms, and x-ray detector systems which have improved instrument stability and precision. Improved software now allows extended automated runs involving diverse setups and better integrates digital imaging and quantitative analysis. However, instrumental performance is not regularly maintained, as WDS are aligned and calibrated during installation but few laboratories appear to check and maintain this calibration. In particular, detector deadtime (DT) data is typically assumed rather than measured, due primarily to the difficulty and inconvenience of the measurement process. This is a source of fundamental systematic error in many microprobe laboratories and is unknown to the analyst, as the magnitude of DT correction is not listed in output by microprobe operating systems. The analyst must remain vigilant to deviations in instrumental alignment and calibration, and microprobe system software must conveniently verify the necessary parameters. Microanalysis of mission critical materials requires an ongoing demonstration of instrumental calibration. Possible approaches to improvements in instrument calibration, quality control, and accuracy will be discussed. Development of a set of core requirements based on discussions with users, researchers, and manufacturers can yield documents that improve and unify the methods by which instruments can be calibrated. These results can be used to

  14. Measurement System of Reducing Temperature Fluctuation of Thermostat Bath for Calibrating Thermocouple

    OpenAIRE

    Zhang, Min; Liang, Feixia; Xie, Yue; Huang, Ruguo; Yuan, Haitao; Lu, Jiahua

    2014-01-01

    International audience; Based on the periodic unsteady state heat conduction theory, a new measurement system of reducing temperature fluctuation of thermostat bath was developed in order to obtain a liquid environment with uniform and constant temperature controlled for the measurement requirements of calibrating thermocouple. The experimental results show that the temperature stability in this measurement system is superior to that in traditional system. The measurement system had the advan...

  15. [Conservative calibration of a clearance monitor system for waste material from nuclear medicine].

    Science.gov (United States)

    Wanke, Carsten; Geworski, Lilli

    2014-09-01

    Clearance monitor systems are used for gross gamma measurements of waste potentially contaminated with radioactivity. These measurements are to make sure that legal requirements, e.g. clearance criteria according to the german radiation protection ordinance, are met. This means that measurement results may overestimate, but must not underestimate the true values. This paper describes a pragmatic way using a calibrated Cs-137 point source to generate a conservative calibration for the clearance monitor system used in the Medizinische Hochschule Hannover (MHH). The most important nuclides used in nuclear medicine are considered. The measurement result reliably overestimates the true value of the activity present in the waste. The calibration is compliant with the demands for conservativity and traceability to national standards.

  16. An indirect accuracy calibration and uncertainty evaluation method for large scale inner dimensional measurement system

    Science.gov (United States)

    Liu, Bai-Ling; Qu, Xing-Hua

    2013-10-01

    In view of present problem of low accuracy, limited range and low automaticity existing in the large-scale diameter inspection instrument, a precise measuring system (robot) was designed based on laser displacement sensor for large-scale inner diameter in this paper. Since the traditional measuring tool of the robot is expensive and hard to manufacture, an indirect calibration method is proposed. In this study, the system eccentric error is calibrated by ring gauge of laboratory. An experiment, which changes the installed order of located rods to introduce located rods' eccentric error, is designed to test whether the spindle eccentric error remains unchanged. The experiment result shows the variation of spindle's eccentricity after changing rods is within 0.02mm. Due to the spindle is an unchanged part of robot, based on Φ584 series robot calibrated by ring gauge, other series robot can be deduced combining with the length of extended arm.

  17. A calibration system for Compton polarimetry at e{sup +}e{sup -} linear colliders

    Energy Technology Data Exchange (ETDEWEB)

    Vormwald, Benedikt; Vauth, Annika [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hamburg Univ. (Germany). Inst. fuer Experimentalphysik; List, Jenny [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-09-15

    Polarimetry with permille-level precision is essential for future electron-positron linear colliders. Compton polarimeters can reach negligible statistical uncertainties within seconds of measurement time. The dominating systematic uncertainties originate from the response and alignment of the detector which records the Compton scattered electrons. The robust baseline technology for the Compton polarimeters foreseen at future linear colliders is based on an array of gas Cherenkov detectors read out by photomultipliers. In this paper, we will present a calibration method which promises to monitor nonlinearities in the response of such a detector at the level of a few permille. This method has been implemented in an LED-based calibration system which matches the existing prototype detector. The performance of this calibration system is sufficient to control the corresponding contribution to the total uncertainty on the extracted polarisation to better than 0.1%.

  18. A Calibration System for Compton Polarimetry at $e^+e^-$ Linear Colliders

    CERN Document Server

    Vormwald, Benedikt; Vauth, Annika

    2015-01-01

    Polarimetry with permille-level precision is essential for future electron-positron linear colliders. Compton polarimeters can reach negligible statistical uncertainties within seconds of measurement time. The dominating systematic uncertainties originate from the response and alignment of the detector which records the Compton scattered electrons. The robust baseline technology for the Compton polarimeters foreseen at future linear colliders is based on an array of gas Cherenkov detectors read out by photomultipliers. In this paper, we will present a calibration method which promises to monitor nonlinearities in the response of such a detector at the level of a few permille. This method has been implemented in an LED-based calibration system which matches the existing prototype detector. The performance of this calibration system is sufficient to control the corresponding contribution to the total uncertainty on the extracted polarisation to better than $0.1\\%$.

  19. Desiccation-Induced Volumetric Shrinkage of Compacted Metakaolin-Treated Black Cotton Soil for a Hydraulic Barriers System

    Science.gov (United States)

    Moses, George; Peter, Oriola F. O.; Osinubi, Kolawole J.

    2016-03-01

    Black cotton soil treated with up to 24% metakaolin (MCL) content was prepared by molding water contents of -2, 0, 2, 4 and 6% of optimum moisture content (OMC) and compacted with British Standard Light (BSL) and West African Standard (WAS) or `Intermediate' energies. The specimens were extruded from the compaction molds and allowed to air dry in a laboratory in order to assess the effect of desiccation-induced shrinkage on the compacted mix for use as a hydraulic barrier in a waste containment application. The results recorded show that the volumetric shrinkage strain (VSS) values were large within the first 10 days of drying; the VSS values increased with a higher molding of the water content, relative to the OMC. The VSS generally increased with a higher initial degree of saturation for the two compactive efforts, irrespective of the level of MCL treatment. Generally, the VSS decreased with an increasing MCL content. Only specimens treated with a minimum 20% MCL content and compacted with the WAS energy satisfied the regulatory maximum VSS of 4% for use as a hydraulic barrier.

  20. Desiccation-Induced Volumetric Shrinkage of Compacted Metakaolin-Treated Black Cotton Soil for a Hydraulic Barriers System

    Directory of Open Access Journals (Sweden)

    Moses George

    2016-03-01

    Full Text Available Black cotton soil treated with up to 24% metakaolin (MCL content was prepared by molding water contents of −2, 0, 2, 4 and 6% of optimum moisture content (OMC and compacted with British Standard Light (BSL and West African Standard (WAS or ‘Intermediate’ energies. The specimens were extruded from the compaction molds and allowed to air dry in a laboratory in order to assess the effect of desiccation-induced shrinkage on the compacted mix for use as a hydraulic barrier in a waste containment application. The results recorded show that the volumetric shrinkage strain (VSS values were large within the first 10 days of drying; the VSS values increased with a higher molding of the water content, relative to the OMC. The VSS generally increased with a higher initial degree of saturation for the two compactive efforts, irrespective of the level of MCL treatment. Generally, the VSS decreased with an increasing MCL content. Only specimens treated with a minimum 20% MCL content and compacted with the WAS energy satisfied the regulatory maximum VSS of 4% for use as a hydraulic barrier.

  1. Calibration of the Accuscan II In Vivo System for I-131 Thyroid Counting

    Energy Technology Data Exchange (ETDEWEB)

    Orval R. Perry; David L. Georgeson

    2011-07-01

    This report describes the March 2011 calibration of the Accuscan II HpGe In Vivo system for I-131 thyroid counting. The source used for the calibration was an Analytics mixed gamma source 82834-121 distributed in an epoxy matrix in a Wheaton Liquid Scintillation Vial with energies from 88.0 keV to 1836.1 keV. The center of the detectors was position 64-feet from the vault floor. This position places the approximate center line of the detectors at the center line of the source in the thyroid tube. The calibration was performed using an RMC II phantom (Appendix J). Validation testing was performed using a Ba-133 source and an ANSI N44.3 Phantom (Appendix I). This report includes an overview introduction and records for the energy/FWHM and efficiency calibrations including verification counting. The Accuscan II system was successfully calibrated for counting the thyroid for I-131 and verified in accordance with ANSI/HPS N13.30-1996 criteria.

  2. The Calibration Model and Simulation Analysis of Circular Scanning Airborne Laser Bathymetry System

    Directory of Open Access Journals (Sweden)

    SHEN Erhua

    2016-08-01

    Full Text Available To improve the positioning accuracy of circular scanning airborne laser bathymetry system, a calibration method is presented in this paper. When the laser points are collected by the bathymetry system on the level area, they should be on the same plane. However, they are not coplanar because of systematic error and random error. So we try to fit the points to a plane, which may help to adjust the errors and then correct the point location.Firstly, the circular scanning airborne laser bathymetry positioning model is derived in the simple mode. The intersection of laser line and sea surface is simulated depending on the mathematical principles of line and plane intersection. Combined with the direction vector of laser line in the water got by the refraction principle, the sea floor plane mathematical equation is used to compute the location of the laser points. Then, the parameter weighted least squares adjustment model is derived with the prior variance introduced, which lays the foundation for the following computing of calibration model. Finally, the calibration adjustment mathematic model and the detailed computing process are derived. The simulation computing and analysis for the calibration process is presented, and some meaningful conclusions for the calibration are achieved.

  3. Calibration of the Accuscan II IN Vivo System for High Energy Lung Counting

    Energy Technology Data Exchange (ETDEWEB)

    Ovard R. Perry; David L. Georgeson

    2011-07-01

    This report describes the April 2011 calibration of the Accuscan II HpGe In Vivo system for high energy lung counting. The source used for the calibration was a NIST traceable lung set manufactured at the University of Cincinnati UCLL43AMEU & UCSL43AMEU containing Am-241 and Eu-152 with energies from 26 keV to 1408 keV. The lung set was used in conjunction with a Realistic Torso phantom. The phantom was placed on the RMC II counting table (with pins removed) between the v-ridges on the backwall of the Accuscan II counter. The top of the detector housing was positioned perpendicular to the junction of the phantom clavicle with the sternum. This position places the approximate center line of the detector housing with the center of the lungs. The energy and efficiency calibrations were performed using a Realistic Torso phantom (Appendix I) and the University of Cincinnati lung set. This report includes an overview introduction and records for the energy/FWHM and efficiency calibration including performance verification and validation counting. The Accuscan II system was successfully calibrated for high energy lung counting and verified in accordance with ANSI/HPS N13.30-1996 criteria.

  4. Calibration of the Accuscan II In Vivo System for I-125 Thyroid Counting

    Energy Technology Data Exchange (ETDEWEB)

    Ovard R. Perry; David L. Georgeson

    2011-07-01

    This report describes the March 2011 calibration of the Accuscan II HpGe In Vivo system for I-125 thyroid counting. The source used for the calibration was a DOE manufactured Am-241/Eu-152 source contained in a 22 ml vial BEA Am-241/Eu-152 RMC II-1 with energies from 26 keV to 344 keV. The center of the detector housing was positioned 64 inches from the vault floor. This position places the approximate center line of the detector housing at the center line of the source in the phantom thyroid tube. The energy and efficiency calibration were performed using an RMC II phantom (Appendix J). Performance testing was conducted using source BEA Am-241/Eu-152 RMC II-1 and Validation testing was performed using an I-125 source in a 30 ml vial (I-125 BEA Thyroid 002) and an ANSI N44.3 phantom (Appendix I). This report includes an overview introduction and records for the energy/FWHM and efficiency calibration including performance verification and validation counting. The Accuscan II system was successfully calibrated for counting the thyroid for I-125 and verified in accordance with ANSI/HPS N13.30-1996 criteria.

  5. Precision calibration method for binocular vision measurement systems based on arbitrary translations and 3D-connection information

    Science.gov (United States)

    Yang, Jinghao; Jia, Zhenyuan; Liu, Wei; Fan, Chaonan; Xu, Pengtao; Wang, Fuji; Liu, Yang

    2016-10-01

    Binocular vision systems play an important role in computer vision, and high-precision system calibration is a necessary and indispensable process. In this paper, an improved calibration method for binocular stereo vision measurement systems based on arbitrary translations and 3D-connection information is proposed. First, a new method for calibrating the intrinsic parameters of binocular vision system based on two translations with an arbitrary angle difference is presented, which reduces the effect of the deviation of the motion actuator on calibration accuracy. This method is simpler and more accurate than existing active-vision calibration methods and can provide a better initial value for the determination of extrinsic parameters. Second, a 3D-connection calibration and optimization method is developed that links the information of the calibration target in different positions, further improving the accuracy of the system calibration. Calibration experiments show that the calibration error can be reduced to 0.09%, outperforming traditional methods for the experiments of this study.

  6. A new in situ electrical calibration system for high temperature Calvet calorimeters.

    Science.gov (United States)

    Razouk, Refat; Hay, Bruno; Himbert, Marc

    2013-09-01

    A new in situ high temperature electrical calibration system was developed at Laboratoire National de Metrologie et d'Essais, Laboratoire Commun de Metrologie and integrated into a heat flux Calvet calorimeter in order to perform accurate and reliable measurements of enthalpy of fusion that are directly traceable to the International System of Units (SI). This system has been designed to enable the calibration of the calorimeter by electrical substitution (Joule effect) as well as the measurement of enthalpy of fusion in perfectly identical experimental conditions. The metrological features (repeatability, linearity, etc.) of the calorimeter have been evaluated with this system by investigating the influence of some parameters (level of energy, dissipation time, and temperature) on the determination of the sensitivity factor of its thermopiles. Two different procedures, for the calibration and the enthalpy measurements with this new electrical calibration system, have been implemented and tested by measuring the enthalpy of fusion of high purity 6N tin. The results obtained are in very good agreement with those measured by other National Metrology Institutes on the same material.

  7. Development and calibration of an accurate 6-degree-of-freedom measurement system with total station

    Science.gov (United States)

    Gao, Yang; Lin, Jiarui; Yang, Linghui; Zhu, Jigui

    2016-12-01

    To meet the demand of high-accuracy, long-range and portable use in large-scale metrology for pose measurement, this paper develops a 6-degree-of-freedom (6-DOF) measurement system based on total station by utilizing its advantages of long range and relative high accuracy. The cooperative target sensor, which is mainly composed of a pinhole prism, an industrial lens, a camera and a biaxial inclinometer, is designed to be portable in use. Subsequently, a precise mathematical model is proposed from the input variables observed by total station, imaging system and inclinometer to the output six pose variables. The model must be calibrated in two levels: the intrinsic parameters of imaging system, and the rotation matrix between coordinate systems of the camera and the inclinometer. Then corresponding approaches are presented. For the first level, we introduce a precise two-axis rotary table as a calibration reference. And for the second level, we propose a calibration method by varying the pose of a rigid body with the target sensor and a reference prism on it. Finally, through simulations and various experiments, the feasibilities of the measurement model and calibration methods are validated, and the measurement accuracy of the system is evaluated.

  8. Energy Performance Assessment of Radiant Cooling System through Modeling and Calibration at Component Level

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Yasin [Malaviya National Institute of Technology (MNIT), Jaipur, India; Mathur, Jyotirmay [Malaviya National Institute of Technology (MNIT), Jaipur, India; Bhandari, Mahabir S [ORNL

    2016-01-01

    The paper describes a case study of an information technology office building with a radiant cooling system and a conventional variable air volume (VAV) system installed side by side so that performancecan be compared. First, a 3D model of the building involving architecture, occupancy, and HVAC operation was developed in EnergyPlus, a simulation tool. Second, a different calibration methodology was applied to develop the base case for assessing the energy saving potential. This paper details the calibration of the whole building energy model to the component level, including lighting, equipment, and HVAC components such as chillers, pumps, cooling towers, fans, etc. Also a new methodology for the systematic selection of influence parameter has been developed for the calibration of a simulated model which requires large time for the execution. The error at the whole building level [measured in mean bias error (MBE)] is 0.2%, and the coefficient of variation of root mean square error (CvRMSE) is 3.2%. The total errors in HVAC at the hourly are MBE = 8.7% and CvRMSE = 23.9%, which meet the criteria of ASHRAE 14 (2002) for hourly calibration. Different suggestions have been pointed out to generalize the energy saving of radiant cooling system through the existing building system. So a base case model was developed by using the calibrated model for quantifying the energy saving potential of the radiant cooling system. It was found that a base case radiant cooling system integrated with DOAS can save 28% energy compared with the conventional VAV system.

  9. Volumetric composition of nanocomposites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Mannila, Juha

    2015-01-01

    Detailed characterisation of the properties of composite materials with nanoscale fibres is central for the further progress in optimization of their manufacturing and properties. In the present study, a methodology for the determination and analysis of the volumetric composition of nanocomposites...... is presented, using cellulose/epoxy and aluminosilicate/polylactate nanocomposites as case materials. The buoyancy method is used for the accurate measurements of materials density. The accuracy of the method is determined to be high, allowing the measured nanocomposite densities to be reported with 5...... significant figures. The plotting of the measured nanocomposite density as a function of the nanofibre weight content is shown to be a first good approach of assessing the porosity content of the materials. The known gravimetric composition of the nanocomposites is converted into a volumetric composition...

  10. The Improved NRL Tropical Cyclone Monitoring System with a Unified Microwave Brightness Temperature Calibration Scheme

    Directory of Open Access Journals (Sweden)

    Song Yang

    2014-05-01

    Full Text Available The near real-time NRL global tropical cyclone (TC monitoring system based on multiple satellite passive microwave (PMW sensors is improved with a new inter-sensor calibration scheme to correct the biases caused by differences in these sensor’s high frequency channels. Since the PMW sensor 89 GHz channel is used in multiple current and near future operational and research satellites, a unified scheme to calibrate all satellite PMW sensor’s ice scattering channels to a common 89 GHz is created so that their brightness temperatures (TBs will be consistent and permit more accurate manual and automated analyses. In order to develop a physically consistent calibration scheme, cloud resolving model simulations of a squall line system over the west Pacific coast and hurricane Bonnie in the Atlantic Ocean are applied to simulate the views from different PMW sensors. To clarify the complicated TB biases due to the competing nature of scattering and emission effects, a four-cloud based calibration scheme is developed (rain, non-rain, light rain, and cloudy. This new physically consistent inter-sensor calibration scheme is then evaluated with the synthetic TBs of hurricane Bonnie and a squall line as well as observed TCs. Results demonstrate the large TB biases up to 13 K for heavy rain situations before calibration between TMI and AMSR-E are reduced to less than 3 K after calibration. The comparison stats show that the overall bias and RMSE are reduced by 74% and 66% for hurricane Bonnie, and 98% and 85% for squall lines, respectively. For the observed hurricane Igor, the bias and RMSE decrease 41% and 25% respectively. This study demonstrates the importance of TB calibrations between PMW sensors in order to systematically monitor the global TC life cycles in terms of intensity, inner core structure and convective organization. A physics-based calibration scheme on TC’s TB corrections developed in this study is able to significantly reduce the

  11. Designing a Signal Conditioning System with Software Calibration for Resistor-feedback Patch Clamp Amplifier.

    Science.gov (United States)

    Hu, Gang; Zhu, Quanhui; Qu, Anlian

    2005-01-01

    In this paper, a programmable signal conditioning system based on software calibration for resistor-feedback patch clamp amplifier (PCA) has been described, this system is mainly composed of frequency correction, programmable gain and filter whose parameters are configured by software automatically to minimize the errors, A lab-designed data acquisition system (DAQ) is used to implement data collections and communications with PC. The laboratory test results show good agreement with design specifications.

  12. Calibration and characterisation with a new laser-based magnetostriction measurement system

    OpenAIRE

    Rafferty, Aran; Bakir, S.; BRABAZON, Dermot; Prescott, Tim

    2009-01-01

    A laser-based magnet measurement system has been developed to measure the magnetostrictive strain of large cylindrical samples. The measurement system incorporates a solenoid capable of generating a maximum magnetic field intensity of 3000 Oe and a laser displacement sensor. For calibration and evaluation purposes, the positive magnetostrictions of two different types of giant magnetostrictive Tb–Dy–Fe-based materials were accessed with this system. A magnetostrictive strain of 622 ppm was ob...

  13. Edge and core Thomson scattering systems and their calibration on the ASDEX Upgrade tokamak.

    Science.gov (United States)

    Kurzan, B; Murmann, H D

    2011-10-01

    A new 10 channel Thomson scattering (TS) system was installed on the ASDEX Upgrade tokamak to measure radial profiles of electron density and temperature at the plasma edge with high radial resolution. Together with the already existing TS system, which is now used for the core plasma, electron density and temperature profiles extending from the edge to the core are now obtained in a single discharge. The TS systems are relatively calibrated by an optical parametric oscillator.

  14. Edge and core Thomson scattering systems and their calibration on the ASDEX Upgrade tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Kurzan, B.; Murmann, H. D. [Max-Planck Institut fuer Plasmaphysik, EURATOM Association Boltzmannstr.2, 85748 Garching (Germany)

    2011-10-15

    A new 10 channel Thomson scattering (TS) system was installed on the ASDEX Upgrade tokamak to measure radial profiles of electron density and temperature at the plasma edge with high radial resolution. Together with the already existing TS system, which is now used for the core plasma, electron density and temperature profiles extending from the edge to the core are now obtained in a single discharge. The TS systems are relatively calibrated by an optical parametric oscillator.

  15. A NEW ELECTRONIC BOARD TO DRIVE THE LASER CALIBRATION SYSTEM OF THE ATLAS HADRON CALORIMETER

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00086824; The ATLAS collaboration

    2016-01-01

    The LASER calibration system of the ATLAS hadron calorimeter aims at monitoring the ~10000 PMTs of the TileCal. The LASER light injected in the PMTs is measured by sets of photodiodes at several stages of the optical path. The monitoring of the photodiodes is performed by a redundant internal calibration system using an LED, a radioactive source, and a charge injection system. The LASer Calibration Rod (LASCAR) electronics card is a major component of the LASER calibration scheme. Housed in a VME crate, its main components include a charge ADC, a TTCRx, a HOLA part, an interface to control the LASER, and a charge injection system. The 13 bits ADC is a 2000pc full-scale converter that processes up to 16 signals stemming from 11 photodiodes, 2 PMTs, and 3 charge injection channels. Two gains are used (x1 and x4) to increase the dynamic range and avoid a saturation of the LASER signal for high intensities. The TTCRx chip (designed by CERN) retrieves LHC signals to synchronize the LASCAR card with the collider. T...

  16. Vacuum gage calibration system for 10 to the minus 8th power to 10 torr

    Science.gov (United States)

    Holanda, R.

    1969-01-01

    Calibration system consists of a gas source, a source pressure gage, source volume, transfer volume and test chamber, plus appropriate piping, valves and vacuum source. It has been modified to cover as broad a range as possible while still providing accuracy and convenience.

  17. The Calibration of High-Speed Camera Imaging System for ELMs Observation on EAST Tokamak

    Science.gov (United States)

    Fu, Chao; Zhong, Fangchuan; Hu, Liqun; Yang, Jianhua; Yang, Zhendong; Gan, Kaifu; Zhang, Bin; East Team

    2016-09-01

    A tangential fast visible camera has been set up in EAST tokamak for the study of edge MHD instabilities such as ELM. To determine the 3-D information from CCD images, Tsai's two-stage technique was utilized to calibrate the high-speed camera imaging system for ELM study. By applying tiles of the passive stabilizers in the tokamak device as the calibration pattern, transformation parameters for transforming from a 3-D world coordinate system to a 2-D image coordinate system were obtained, including the rotation matrix, the translation vector, the focal length and the lens distortion. The calibration errors were estimated and the results indicate the reliability of the method used for the camera imaging system. Through the calibration, some information about ELM filaments, such as positions and velocities were obtained from images of H-mode CCD videos. supported by National Natural Science Foundation of China (No. 11275047), the National Magnetic Confinement Fusion Science Program of China (No. 2013GB102000)

  18. A Fast Calibration System for SiPM Based Scintillator HCAL Detector

    CERN Document Server

    Polak, I

    2015-01-01

    with mid-range a fixed-intensity light pulse. The full SiPM response function is cross-checked by varying the light intensity from zero to the saturation level. In calibration systems we developed, we concentrate especially on the aspect a high dynamic range of pre...

  19. CALIS - a CALibration Insertion System for the DarkSide-50 dark matter search experiment

    Energy Technology Data Exchange (ETDEWEB)

    Agnes, P.; et al.

    2012-12-28

    This paper describes the design, fabrication, commissioning and use of a CALibration source Insertion System (CALIS) in the DarkSide-50 direct dark matter search experiment. CALIS deploys radioactive sources into the liquid scintillator veto to characterize the detector response and detection efficiency of the DarkSide-50 Liquid Argon Time Projection Chamber, and the surrounding 30 t organic liquid scintillator neutron veto. It was commissioned in September 2014 and has been used successfully in several gamma and neutron source campaigns since then. A description of the hardware and an excerpt of calibration analysis results are given below.

  20. CALIS - a CALibration Insertion System for the DarkSide-50 dark matter search experiment

    CERN Document Server

    Agnes, P; Alexander, T; Alton, A K; Asner, D M; Back, H O; Baldin, B; Biery, K; Bocci, V; Bonfini, G; Bonivento, W; Bossa, M; Bottino, B; Brigatti, A; Brodsky, J; Budano, F; Bussino, S; Cadeddu, M; Cadonati, L; Cadoni, M; Calaprice, F; Canci, N; Candela, A; Caravati, M; Cariello, M; Carlini, M; Catalanotti, S; Cavalcante, P; Chepurnov, A; Cicalo, C; Cocco, A G; Covone, G; D'Angelo, D; D'Incecco, M; Davini, S; De Cecco, S; De Deo, M; De Vincenzi, M; Derbin, A; Devoto, A; Di Eusanio, F; Di Pietro, G; Dionisi, C; Edkins, E; Empl, A; Fan, A; Fiorillo, G; Fomenko, K; Forster, G; Franco, D; Gabriele, F; Galbiati, C; Giagu, S; Giganti, C; Giovanetti, G K; Goretti, A M; Granato, F; Grandi, L; Gromov, M; Guan, M; Guardincerri, Y; Hackett, B R; Herner, K; Hughes, D; Humble, P; Hungerford, E V; Ianni, Al; Ianni, An; James, I; Johnson, T N; Jollet, C; Keeter, K; Kendziora, C L; Koh, G; Korablev, D; Korga, G; Kubankin, A; Li, X; Lissia, M; Loer, B; Lombardi, P; Longo, G; Ma, Y; Machulin, I N; Mandarano, A; Mari, S M; Maricic, J; Marini, L; Martoff, C J; Meregaglia, A; Meyers, P D; Milincic, R; Miller, J D; Montanari, D; Monte, A; Mount, B J; Muratova, V N; Musico, P; Napolitano, J; Agasson, A Navrer; Odrowski, S; Orsini, M; Ortica, F; Pagani, L; Pallavicini, M; Pantic, E; Parmeggiano, S; Pelczar, K; Pelliccia, N; Pocar, A; Pordes, S; Pugachev, D A; Qian, H; Randle, K; Ranucci, G; Razeti, M; Razeto, A; Reinhold, B; Renshaw, A L; Rescigno, M; Riffard, Q; Romani, A; Rossi, B; Rossi, N; Rountree, D; Sablone, D; Saggese, P; Saldanha, R; Sands, W; Savarese, C; Schlitzer, B; Segreto, E; Semenova, D A; Shields, E; Singh, P N; Skorokhvatov, M D; Smirnov, O; Sotnikov, A; Stanford, C; Suvorov, Y; Tartaglia, R; Tatarowicz, J; Testera, G; Tonazzo, A; Trinchese, P; Unzhakov, E V; Verducci, M; Vishneva, A; Vogelaar, B; Wada, M; Walker, S; Wang, H; Wang, Y; Watson, A W; Westerdale, S; Wilhelmi, J; Wojcik, M M; Xiang, Xi; Xiao, X; Xu, J; Yang, C; Zec, A; Zhong, W; Zhu, C; Zuzel, G

    2016-01-01

    This paper describes the design, fabrication, commissioning and use of a CALibration source Insertion System (CALIS) in the DarkSide-50 direct dark matter search experiment. CALIS deploys radioactive sources into the liquid scintillator veto to characterize the detector response and detection efficiency of the DarkSide-50 Liquid Argon Time Projection Chamber, and the surrounding 30 t organic liquid scintillator neutron veto. It was commissioned in September 2014 and has been used successfully in several gamma and neutron source campaigns since then. A description of the hardware and an excerpt of calibration analysis results are given below.

  1. A Novel Camera Calibration Algorithm as Part of an HCI System: Experimental Procedure and Results

    Directory of Open Access Journals (Sweden)

    Sauer Kristal

    2006-02-01

    Full Text Available Camera calibration is an initial step employed in many computer vision applications for the estimation of camera parameters. Along with images of an arbitrary scene, these parameters allow for inference of the scene's metric information. This is a primary reason for camera calibration's significance to computer vision. In this paper, we present a novel approach to solving the camera calibration problem. The method was developed as part of a Human Computer Interaction (HCI System for the NASA Virtual GloveBox (VGX Project. Our algorithm is based on the geometric properties of perspective projections and provides a closed form solution for the camera parameters. Its accuracy is evaluated in the context of the NASA VGX, and the results indicate that our algorithm achieves accuracy similar to other calibration methods which are characterized by greater complexity and computational cost. Because of its reliability and wide variety of potential applications, we are confident that our calibration algorithm will be of interest to many.

  2. Metallicity calibrations for dwarf stars and giants in the Geneva photometric system

    Science.gov (United States)

    Netopil, Martin

    2017-08-01

    We use the most homogeneous Geneva seven-colour photometric system to derive new metallicity calibrations for early A- to K-type stars that cover both, dwarf stars and giants. The calibrations are based on several spectroscopic data sets that were merged to a common scale, and we applied them to open cluster data to obtain an additional proof of the metallicity scale and accuracy. In total, metallicities of 54 open clusters are presented. The accuracy of the calibrations for single stars is in general below 0.1 dex, but for the open cluster sample with mean values based on several stars we find a much better precision, a scatter as low as about 0.03 dex. Furthermore, we combine the new results with another comprehensive photometric data set to present a catalogue of mean metallicities for more than 3000 F- and G-type dwarf stars with σ ˜ 0.06 dex. The list was extended by more than 1200 hotter stars up to about 8500 K (or spectral type A3) by taking advantage of their almost reddening free characteristic in the new Geneva metallicity calibrations. These two large samples are well suited as primary or secondary calibrators of other data, and we already identified about 20 spectroscopic data sets that show offsets up to about 0.4 dex.

  3. A novel calibration method for non-orthogonal shaft laser theodolite measurement system

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Bin, E-mail: wubin@tju.edu.cn, E-mail: xueting@tju.edu.cn; Yang, Fengting; Ding, Wen [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072 (China); Xue, Ting, E-mail: wubin@tju.edu.cn, E-mail: xueting@tju.edu.cn [College of Electrical Engineering and Automation, Tianjin Key Laboratory of Process Measurement and Control, Tianjin University, Tianjin 300072 (China)

    2016-03-15

    Non-orthogonal shaft laser theodolite (N-theodolite) is a new kind of large-scale metrological instrument made up by two rotary tables and one collimated laser. There are three axes for an N-theodolite. According to naming conventions in traditional theodolite, rotary axes of two rotary tables are called as horizontal axis and vertical axis, respectively, and the collimated laser beam is named as sight axis. And the difference between N-theodolite and traditional theodolite is obvious, since the former one with no orthogonal and intersecting accuracy requirements. So the calibration method for traditional theodolite is no longer suitable for N-theodolite, while the calibration method applied currently is really complicated. Thus this paper introduces a novel calibration method for non-orthogonal shaft laser theodolite measurement system to simplify the procedure and to improve the calibration accuracy. A simple two-step process, calibration for intrinsic parameters and for extrinsic parameters, is proposed by the novel method. And experiments have shown its efficiency and accuracy.

  4. A novel calibration method for non-orthogonal shaft laser theodolite measurement system

    Science.gov (United States)

    Wu, Bin; Yang, Fengting; Ding, Wen; Xue, Ting

    2016-03-01

    Non-orthogonal shaft laser theodolite (N-theodolite) is a new kind of large-scale metrological instrument made up by two rotary tables and one collimated laser. There are three axes for an N-theodolite. According to naming conventions in traditional theodolite, rotary axes of two rotary tables are called as horizontal axis and vertical axis, respectively, and the collimated laser beam is named as sight axis. And the difference between N-theodolite and traditional theodolite is obvious, since the former one with no orthogonal and intersecting accuracy requirements. So the calibration method for traditional theodolite is no longer suitable for N-theodolite, while the calibration method applied currently is really complicated. Thus this paper introduces a novel calibration method for non-orthogonal shaft laser theodolite measurement system to simplify the procedure and to improve the calibration accuracy. A simple two-step process, calibration for intrinsic parameters and for extrinsic parameters, is proposed by the novel method. And experiments have shown its efficiency and accuracy.

  5. Monte Carlo Studies for the Calibration System of the GERDA Experiment

    CERN Document Server

    Baudis, Laura; Froborg, Francis; Tarka, Michal

    2013-01-01

    The GERmanium Detector Array, GERDA, searches for neutrinoless double beta decay in Ge-76 using bare high-purity germanium detectors submerged in liquid argon. For the calibration of these detectors gamma emitting sources have to be lowered from their parking position on top of the cryostat over more than five meters down to the germanium crystals. With the help of Monte Carlo simulations, the relevant parameters of the calibration system were determined. It was found that three Th-228 sources with an activity of 20 kBq each at two different vertical positions will be necessary to reach sufficient statistics in all detectors in less than four hours of calibration time. These sources will contribute to the background of the experiment with a total of (1.07 +/- 0.04(stat) +0.13 -0.19(sys)) 10^{-4} cts/(keV kg yr) when shielded from below with 6 cm of tantalum in the parking position.

  6. Scanner external calibration algorithm based on fixed point in robot remanufacturing system

    Institute of Scientific and Technical Information of China (English)

    ZHU Sheng; CUI Pei-zhi; SHEN Chan-duo; GUO Ying-chun

    2005-01-01

    This paper deals with the scanner exterior calibration algorithm when the scanner is arranged by the robot and the object scanned is fixed on a rotate device in the Robot Remanufacturing System. The method of calibrating the relationship between the scanner coordinate and the robot Tool0, such as the rotation, Rx, Ry, R,, and the transformation X, Y, Z is studied. The data of Tool0 can be directly obtained from the relationship with the robot base-coordinate. So, the coordinate relationship between the scanner coordinate and the robot base coordinate can be easily gotten. This paper explains the basic algorithm theory, computing method, data collecting process and the resulted data in detail. The calibration algorithm is deduced under the orthogonal coordinate.

  7. Some tests of wet tropospheric calibration for the CASA Uno Global Positioning System experiment

    Science.gov (United States)

    Dixon, T. H.; Wolf, S. Kornreich

    1990-01-01

    Wet tropospheric path delay can be a major error source for Global Positioning System (GPS) geodetic experiments. Strategies for minimizing this error are investigted using data from CASA Uno, the first major GPS experiment in Central and South America, where wet path delays may be both high and variable. Wet path delay calibration using water vapor radiometers (WVRs) and residual delay estimation is compared with strategies where the entire wet path delay is estimated stochastically without prior calibration, using data from a 270-km test baseline in Costa Rica. Both approaches yield centimeter-level baseline repeatability and similar tropospheric estimates, suggesting that WVR calibration is not critical for obtaining high precision results with GPS in the CASA region.

  8. Simulation of random events for adaptive control systems calibration

    Directory of Open Access Journals (Sweden)

    Drăgoi Mircea Viorel

    2017-01-01

    Full Text Available The paper deals with a mathematical model that simulates the random occurrence of events during cutting processes by milling. The evolution of certain parameters that typify the cutting processes depends on predictable and non-predictable variables. In this context, either the material hardness that varies in different sides of billet, or cutting depth, can act as non-predictable variables. In order to design a response in terms of cutting parameters to non-predictable variations of inputs, a simulation of such phenomena is very useful. A mathematical model that generates random events, both in terms of non-uniform frequency and intensity is here described. A virtual instrument built in LabVIEW generates (pseudo random events based on a combination of random numbers, as the evolution of the simulated process to be much like a real one. Furthermore the user of virtual instrument can generate himself events at certain moments and of certain intensity. This can be a useful tool to study the algorithms of designing the response which should re-balance the process within adaptive control systems.

  9. Mathematical Modeling of Electrolyte Flow Dynamic Patterns and Volumetric Flow Penetrations in the Flow Channel over Porous Electrode Layered System in Vanadium Flow Battery with Serpentine Flow Field Design

    CERN Document Server

    Ke, Xinyou; Alexander, J Iwan D; Savinell, Robert F

    2016-01-01

    In this work, a two-dimensional mathematical model is developed to study the flow patterns and volumetric flow penetrations in the flow channel over the porous electrode layered system in vanadium flow battery with serpentine flow field design. The flow distributions at the interface between the flow channel and porous electrode are examined. It is found that the non-linear pressure distributions can distinguish the interface flow distributions under the ideal plug flow and ideal parabolic flow inlet boundary conditions. However, the volumetric flow penetration within the porous electrode beneath the flow channel through the integration of interface flow velocity reveals that this value is identical under both ideal plug flow and ideal parabolic flow inlet boundary conditions. The volumetric flow penetrations under the advection effects of flow channel and landing/rib are estimated. The maximum current density achieved in the flow battery can be predicted based on the 100% amount of electrolyte flow reactant ...

  10. Portable 3D laser-camera calibration system with color fusion for SLAM

    Directory of Open Access Journals (Sweden)

    Javier Navarrete

    2013-03-01

    Full Text Available Nowadays, the use of RGB-D sensors have focused a lot of research in computer vision and robotics. These kinds of sensors, like Kinect, allow to obtain 3D data together with color information. However, their working range is limited to less than 10 meters, making them useless in some robotics applications, like outdoor mapping. In these environments, 3D lasers, working in ranges of 20-80 meters, are better. But 3D lasers do not usually provide color information. A simple 2D camera can be used to provide color information to the point cloud, but a calibration process between camera and laser must be done. In this paper we present a portable calibration system to calibrate any traditional camera with a 3D laser in order to assign color information to the 3D points obtained. Thus, we can use laser precision and simultaneously make use of color information. Unlike other techniques that make use of a three-dimensional body of known dimensions in the calibration process, this system is highly portable because it makes use of small catadioptrics that can be placed in a simple manner in the environment. We use our calibration system in a 3D mapping system, including Simultaneous Location and Mapping (SLAM, in order to get a 3D colored map which can be used in different tasks. We show that an additional problem arises: 2D cameras information is different when lighting conditions change. So when we merge 3D point clouds from two different views, several points in a given neighborhood could have different color information. A new method for color fusion is presented, obtaining correct colored maps. The system will be tested by applying it to 3D reconstruction.

  11. Influence of increment of gantry angle and number of arcs on esophageal volumetric modulated arc therapy planning in Monaco planning system: A planning study

    Directory of Open Access Journals (Sweden)

    L Nithya

    2014-01-01

    Full Text Available The objective of this study was to analyze the influence of the increment of gantry angle and the number of arcs on esophageal volumetric modulated arc therapy plan. All plans were done in Monaco planning system for Elekta Synergy linear accelerator with 80 multileaf collimator (MLC. Volumetric modulated arc therapy (VMAT plans were done with different increment of gantry angle like 15 o , 20 o , 30 o and 40 o . The remaining parameters were similar for all the plans. The results were compared. To compare the plan quality with number of arcs, VMAT plans were done with single and dual arc with increment of gantry angle of 20 o . The dose to gross tumor volume (GTV for 60 Gy and planning target volume (PTV for 48 Gy was compared. The dosimetric parameters D 98% , D 95% , D 50% and D max of GTV were analyzed. The homogeneity index (HI and conformity index (CI of GTV were studied and the dose to 98% and 95% of PTV was analyzed. Maximum dose to spinal cord and planning risk volume of cord (PRV cord was compared. The Volume of lung receiving 10 Gy, 20 Gy and mean dose was analyzed. The volume of heart receiving 30 Gy and 45 Gy was compared. The volume of normal tissue receiving greater than 2 Gy and 5 Gy was compared. The number of monitor units (MU required to deliver the plans were compared. The plan with larger increment of gantry angle proved to be superior to smaller increment of gantry angle plans in terms of dose coverage, HI, CI and normal tissue sparing. The number of arcs did not make any difference in the quality of the plan.

  12. Determination of action thresholds for electromagnetic tracking system-guided hypofractionated prostate radiotherapy using volumetric modulated arc therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pengpeng; Mah, Dennis; Happersett, Laura; Cox, Brett; Hunt, Margie; Mageras, Gig [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States); Department of Radiation Oncology, Montefiore Medical Center, Bronx, New York 10467 (United States); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States); Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021 (United States)

    2011-07-15

    Purpose: Hypofractionated prostate radiotherapy may benefit from both volumetric modulated arc therapy (VMAT) due to shortened treatment time and intrafraction real-time monitoring provided by implanted radiofrequency(RF) transponders. The authors investigate dosimetrically driven action thresholds (whether treatment needs to be interrupted and patient repositioned) in VMAT treatment with electromagnetic (EM) tracking. Methods: VMAT plans for five patients are generated for prescription doses of 32.5 and 42.5 Gy in five fractions. Planning target volume (PTV) encloses the clinical target volume (CTV) with a 3 mm margin at the prostate-rectal interface and 5 mm elsewhere. The VMAT delivery is modeled using 180 equi-spaced static beams. Intrafraction prostate motion is simulated in the plan by displacing the beam isocenter at each beam assuming rigid organ motion according to a previously recorded trajectory of the transponder centroid. The cumulative dose delivered in each fraction is summed over all beams. Two sets of 57 prostate motion trajectories were randomly selected to form a learning and a testing dataset. Dosimetric end points including CTV D95%, rectum wall D1cc, bladder wall D1cc, and urethra Dmax, are analyzed against motion characteristics including the maximum amplitude of the anterior-posterior (AP), superior-inferior (SI), and left-right components. Action thresholds are triggered when intrafraction motion causes any violations of dose constraints to target and organs at risk (OAR), so that treatment is interrupted and patient is repositioned. Results: Intrafraction motion has a little effect on CTV D95%, indicating PTV margins are adequate. Tight posterior and inferior action thresholds around 1 mm need to be set in a patient specific manner to spare organs at risk, especially when the prescription dose is 42.5 Gy. Advantages of setting patient specific action thresholds are to reduce false positive alarms by 25% when prescription dose is low, and

  13. Calibration of the Multi-camera Registration System for Visual Navigation Benchmarking

    Directory of Open Access Journals (Sweden)

    Adam Schmidt

    2014-06-01

    Full Text Available This paper presents the complete calibration procedure of a multi-camera system for mobile robot motion registration. Optimization-based, purely visual methods for the estimation of the relative poses of the motion registration system cameras, as well as the relative poses of the cameras and markers placed on the mobile robot were proposed. The introduced methods were applied to the calibration of the system and the quality of the obtained results was evaluated. The obtained results compare favourably with the state of the art solutions, allowing the use of the considered motion registration system for the accurate reconstruction of the mobile robot trajectory and to register new datasets suitable for the benchmarking of indoor, visual-based navigation algorithms.

  14. The calibration system for the photomultiplier array of the SNO+ experiment

    CERN Document Server

    Alves, R; Bradbury, S; Carvalho, J; Chauhan, D; Clark, K; Coulter, I; Descamps, F; Falk, E; Gurriana, L; Kraus, C; Lefeuvre, G; Maio, A; Maneira, J; Mottram, M; Peeters, S; Rose, J; Seabra, L; Sinclair, J; Skensved, P; Waterfield, J; White, R; Wilson, J R

    2014-01-01

    A light injection system using LEDs and optical fibres was designed for the calibration and monitoring of the photomultiplier array of the SNO+ experiment at SNOLAB. Large volume, non-segmented, low-background detectors for rare event physics, such as the multi-purpose SNO+ experiment, need a calibration system that allow an accurate and regular measurement of the performance parameters of their photomultiplier arrays, while minimising the risk of radioactivity ingress. The design implemented for SNO+ uses a set of optical fibres to inject light pulses from external LEDs into the detector. The design, fabrication and installation of this light injection system, as well as the first commissioning tests, are described in this paper. Monte Carlo simulations were compared with the commissioning test results, confirming that the system meets the performance requirements.

  15. Design and Instrumentation of a Measurement and Calibration System for an Acoustic Telemetry System

    Directory of Open Access Journals (Sweden)

    Zhiqun Deng

    2010-03-01

    Full Text Available The Juvenile Salmon Acoustic Telemetry System (JSATS is an active sensing technology developed by the U.S. Army Corps of Engineers, Portland District, for detecting and tracking small fish. It is used primarily for evaluating behavior and survival of juvenile salmonids migrating through the Federal Columbia River Power System to the Pacific Ocean. It provides critical data for salmon protection and development of more “fish-friendly” hydroelectric facilities. The objective of this study was to design and build a Measurement and Calibration System (MCS for evaluating the JSATS components, because the JSATS requires comprehensive acceptance and performance testing in a controlled environment before it is deployed in the field. The MCS consists of a reference transducer, a water test tank lined with anechoic material, a motion control unit, a reference receiver, a signal conditioner and amplifier unit, a data acquisition board, MATLAB control and analysis interface, and a computer. The fully integrated MCS has been evaluated successfully at various simulated distances and using different encoded signals at frequencies within the bandwidth of the JSATS transmitter. The MCS provides accurate acoustic mapping capability in a controlled environment and automates the process that allows real-time measurements and evaluation of the piezoelectric transducers, sensors, or the acoustic fields. The MCS has been in use since 2009 for acceptance and performance testing of, and further improvements to, the JSATS.

  16. Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

    Science.gov (United States)

    P. Veres; J. B. Gilman; J. M. Roberts; W. C. Kuster; C. Warneke; I. R. Burling; J. de Gouw

    2010-01-01

    We report on the development of an accurate, portable, dynamic calibration system for volatile organic compounds (VOCs). The Mobile Organic Carbon Calibration System (MOCCS) combines the production of gas-phase VOC standards using permeation or diffusion sources with quantitative total organic carbon (TOC) conversion on a palladium surface to CO2 in the presence of...

  17. Test of candidate light distributors for the muon (g$-$2) laser calibration system

    CERN Document Server

    Anastasi, A; Baffigi, F; Cantatore, G; Cauz, D; Corradi, G; Dabagov, S; Di Sciascio, G; Di Stefano, R; Ferrari, C; Fienberg, A T; Fioretti, A; Fulgentini, L; Gabbanini, C; Gizzi, L A; Hampai, D; Hertzog, D W; Iacovacci, M; Karuza, M; Kaspar, J; Koester, P; Labate, L; Mastroianni, S; Moricciani, D; Pauletta, G; Santi, L; Venanzoni, G

    2015-01-01

    The new muon (g-2) experiment E989 at Fermilab will be equipped with a laser calibration system for all the 1296 channels of the calorimeters. An integrating sphere and an alternative system based on an engineered diffuser have been considered as possible light distributors for the experiment. We present here a detailed comparison of the two based on temporal response, spatial uniformity, transmittance and time stability.

  18. PMT response drift of ATLAS Tile Laser II calibration system: an introduction of a new method

    CERN Document Server

    Di Gregorio, Giulia

    2016-01-01

    In this article I describe the performance of the monitoring diodes of the Laser II system, a new system for run II used to calibrate the gain variation of PMTs in between two cesium scan. I also show a new method to measure the PMT drift response that it is compared to the method used up to now (Clermont-Ferrant) corrected with the Pisa method. The agreement between the two method is within 0.2%.

  19. Challenges when using real-world bio-data to calibrate simulation systems.

    Science.gov (United States)

    Blount, Elaine M; Ringleb, Stacie I; Tolk, Andreas

    2011-01-01

    Computer simulations allow us to gain insight into biological systems that would not be possible without destroying or changing the system in significant ways. To ensure that results are relevant, real-world bio-data should be used to calibrate simulations. Real-world data contain uncertainty due to the nature of how it is obtained. This chapter provides various sources on uncertainty and methods to cope with this challenge.

  20. A new automatic system for angular measurement and calibration in radiometric instruments.

    Science.gov (United States)

    Marquez, Jose Manuel Andujar; Bohórquez, Miguel Ángel Martínez; Garcia, Jonathan Medina; Nieto, Francisco Jose Aguilar

    2010-01-01

    This paper puts forward the design, construction and testing of a new automatic system for angular-response measurement and calibration in radiometric instruments. Its main characteristics include precision, speed, resolution, noise immunity, easy programming and operation. The developed system calculates the cosine error of the radiometer under test by means of a virtual instrument, from the measures it takes and through a mathematical procedure, thus allowing correcting the radiometer with the aim of preventing cosine error in its measurements.

  1. A New Automatic System for Angular Measurement and Calibration in Radiometric Instruments

    Directory of Open Access Journals (Sweden)

    Jose Manuel Andujar Marquez

    2010-04-01

    Full Text Available This paper puts forward the design, construction and testing of a new automatic system for angular-response measurement and calibration in radiometric instruments. Its main characteristics include precision, speed, resolution, noise immunity, easy programming and operation. The developed system calculates the cosine error of the radiometer under test by means of a virtual instrument, from the measures it takes and through a mathematical procedure, thus allowing correcting the radiometer with the aim of preventing cosine error in its measurements.

  2. Phase calibration of sonar systems using standard targets and dual-frequency transmission pulses.

    Science.gov (United States)

    Islas-Cital, Alan; Atkins, Philip R; Foo, Kae Y; Picó, Ruben

    2011-10-01

    The phase angle component of the complex frequency response of a sonar system operating near transducer resonance is usually distorted. Interpretation and classification of the received sonar signal benefits from the preservation of waveform fidelity over the full bandwidth. A calibration process that measures the phase response in addition to the amplitude response is thus required. This paper describes an extension to the standard-target calibration method to include phase angle, without affecting the experimental apparatus, by using dual-frequency transmission pulses and frequency-domain data processing. This approach reduces the impact of unknown range and sound speed parameters upon phase calibration accuracy, as target phase is determined from the relationship of the two frequency components instead of relying on a local phase reference. Tungsten carbide spheres of various sizes were used to simultaneously calibrate the amplitude and phase response of an active sonar system in a laboratory tank. Experimental measurements of target phase spectra are in good agreement with values predicted from a theoretical model based upon full-wave analysis, over an operating frequency of 50-125 kHz.

  3. Design of an expert system to automatically calibrate impedance control for powered knee prostheses.

    Science.gov (United States)

    Wang, Ding; Liu, Ming; Zhang, Fan; Huang, He

    2013-06-01

    Many currently available powered knee prostheses (PKP) use finite state impedance control to operate a prosthetic knee joint. The desired impedance values were usually manually calibrated with trial-and-error in order to enable near-normal walking pattern. However, such a manual approach is inaccurate, time consuming, and impractical. This paper aimed to design an expert system that can tune the control impedance for powered knee prostheses automatically and quickly. The expert system was designed based on fuzzy logic inference (FLI) to match the desired knee motion and gait timing while walking. The developed system was validated on an able-bodied subject wearing a powered prosthesis. Preliminary experimental results demonstrated that the developed expert system can converge the user's knee profile and gait timing to the desired values within 2 minutes. Additionally, after the auto-tuning procedure, the user produced more symmetrical gait. These preliminary results indicate the promise of the designed expert system for quick and accuracy impedance calibration, which can significantly improve the practical value of powered lower limb prosthesis. Continuous engineering efforts are still needed to determine the calibration objectives and validate the expert system.

  4. Flexible Volumetric Structure

    Science.gov (United States)

    Cagle, Christopher M. (Inventor); Schlecht, Robin W. (Inventor)

    2014-01-01

    A flexible volumetric structure has a first spring that defines a three-dimensional volume and includes a serpentine structure elongatable and compressible along a length thereof. A second spring is coupled to at least one outboard edge region of the first spring. The second spring is a sheet-like structure capable of elongation along an in-plane dimension thereof. The second spring is oriented such that its in-plane dimension is aligned with the length of the first spring's serpentine structure.

  5. ISAC time-of-flight system with laser-based calibration

    Energy Technology Data Exchange (ETDEWEB)

    Verzilov, V.A., E-mail: verzilov@triumf.ca

    2015-06-11

    The time-of-flight (TOF) system is available at the ISAC rare isotope facility to measure the energy of stable and radioactive ion beams in the range of 0.5–22 Mev/u. The system, comprised of three secondary electron emission based monitors, is operated with practically all available beam intensities starting from as low as 10{sup 3} ions per second. Recently the system was equipped with the calibration setup based on a 266 nm ultraviolet laser. Laser light interacting with the TOF monitors generates secondary electrons due to the photoelectric effect and acts as a reference beam traveling at a well- known velocity. After calibration, accuracy of energy measurements improved to be better than 0.1%.

  6. Development of the laser alignment system with PSD used for shaft calibration

    Science.gov (United States)

    Jiao, Guohua; Li, Yulin; Hu, Baowen

    2006-02-01

    Shaft calibration is an important technique during installation and maintenance of a rotating machine. It requires unique and high-precision measurement instruments with calculation capability, and relies on experience on heavy, high-speed, or high-temperature machines. A high-precision laser alignment system has been designed using PSD (Position Sensing Detector) to change traditional manual way of shaft calibration and to make the measurement easier and more accurate. The system is comprised of two small measuring units (Laser transmitter and detector) and a hand operated control unit or a PC. Such a laser alignment system has been used in some actual shaft alignment with offset resolution 1.5μm and angular resolution 0.1°.

  7. Users manual for an expert system (HSPEXP) for calibration of the hydrological simulation program; Fortran

    Science.gov (United States)

    Lumb, A.M.; McCammon, R.B.; Kittle, J.L.

    1994-01-01

    Expert system software was developed to assist less experienced modelers with calibration of a watershed model and to facilitate the interaction between the modeler and the modeling process not provided by mathematical optimization. A prototype was developed with artificial intelligence software tools, a knowledge engineer, and two domain experts. The manual procedures used by the domain experts were identified and the prototype was then coded by the knowledge engineer. The expert system consists of a set of hierarchical rules designed to guide the calibration of the model through a systematic evaluation of model parameters. When the prototype was completed and tested, it was rewritten for portability and operational use and was named HSPEXP. The watershed model Hydrological Simulation Program--Fortran (HSPF) is used in the expert system. This report is the users manual for HSPEXP and contains a discussion of the concepts and detailed steps and examples for using the software. The system has been tested on watersheds in the States of Washington and Maryland, and the system correctly identified the model parameters to be adjusted and the adjustments led to improved calibration.

  8. Double-layer parallelization for hydrological model calibration on HPC systems

    Science.gov (United States)

    Zhang, Ang; Li, Tiejian; Si, Yuan; Liu, Ronghua; Shi, Haiyun; Li, Xiang; Li, Jiaye; Wu, Xia

    2016-04-01

    Large-scale problems that demand high precision have remarkably increased the computational time of numerical simulation models. Therefore, the parallelization of models has been widely implemented in recent years. However, computing time remains a major challenge when a large model is calibrated using optimization techniques. To overcome this difficulty, we proposed a double-layer parallel system for hydrological model calibration using high-performance computing (HPC) systems. The lower-layer parallelism is achieved using a hydrological model, the Digital Yellow River Integrated Model, which was parallelized by decomposing river basins. The upper-layer parallelism is achieved by simultaneous hydrological simulations with different parameter combinations in the same generation of the genetic algorithm and is implemented using the job scheduling functions of an HPC system. The proposed system was applied to the upstream of the Qingjian River basin, a sub-basin of the middle Yellow River, to calibrate the model effectively by making full use of the computing resources in the HPC system and to investigate the model's behavior under various parameter combinations. This approach is applicable to most of the existing hydrology models for many applications.

  9. A robust photometric calibration framework for projector-camera display system

    Institute of Scientific and Technical Information of China (English)

    Wenhai Zou; Haisong Xu

    2009-01-01

    A novel photometric calibration framework is presented for a projector-camera (ProCam) display system,which is currently under booming development.Firstly,a piccewise bilinear model and five 5-ary color coding images are used to construct the homography between the image planes of a projector and a camcra.Secondly,a photometric model is proposed to describe the data flow of the ProCam display system for displaying color images on colored surface in a general way. An efficient self-calibration algorithm is correspondingly put forward to recover the model parameters.Aiming to adapt this algorithm to different types of ProCam display system robustly,a 3×7 masking coupling matrix and a patches image with 1024 color samples are adopted to fit the complex channel interference function of the display system.Finally,the experimental results demonstrate the validity and superiority of this calibration algorithm for the ProCam display system.

  10. IMITATION OF STANDARD VOLUMETRIC ACTIVITY METAL SAMPLES

    Directory of Open Access Journals (Sweden)

    A. I. Zhukouski

    2016-01-01

    Full Text Available Due to the specific character of problems in the field of ionizing radiation spectroscopy, the R&D and making process of standard volumetric activity metal samples (standard samples for calibration and verification of spectrometric equipment is not only expensive, but also requires the use of highly qualified experts and a unique specific equipment. Theoretical and experimental studies performed have shown the possibility to use imitators as a set of alternating point sources of gamma radiation and metal plates and their use along with standard volumetric activity metal samples for calibration of scintillation-based detectors used in radiation control in metallurgy. Response functions or instrumental spectra of such spectrometer to radionuclides like 137Cs, 134Cs, 152Eu, 154Eu, 60Co, 54Mn, 232Th, 226Ra, 65Zn, 125Sb+125mTe, 106Ru+106Rh, 94Nb, 110mAg, 233U, 234U, 235U and 238U are required for calibration in a given measurement geometry. Standard samples in the form of a probe made of melt metal of a certain diameter and height are used in such measurements. However, the production of reference materials is costly and even problematic for such radionuclides as 94Nb, 125Sb+125mTe, 234U, 235U  etc. A recognized solution to solve this problem is to use the Monte-Carlo simulation method. Instrumental experimental and theoretical spectra obtained by using standard samples and their imitators show a high compliance between experimental spectra of real samples and the theoretical ones of their Monte-Carlo models, between spectra of real samples and the ones of their imitators and finally, between experimental spectra of real sample imitators and the theoretical ones of their Monte-Carlo models. They also have shown the adequacy and consistency of the approach in using a combination of metal scattering layers and reference point gamma-ray sources instead of standard volumetric activity metal samples. As for using several reference point gamma-ray sources

  11. The laser calibration system for the STACEE ground-based gamma ray detector

    CERN Document Server

    Hanna, D

    2002-01-01

    We describe the design and performance of the laser system used for calibration monitoring of components of the STACEE detector. STACEE is a ground based gamma ray detector which uses the heliostats of a solar power facility to collect and focus Cherenkov light onto a system of secondary optics and photomultiplier tubes. To monitor the gain and check the linearity and timing properties of the phototubes and associated electronics, a system based on a dye laser, neutral density filters and optical fibres has been developed. In this paper we describe the system and present some results from initial tests made with it.

  12. System calibration and image reconstruction for a new small-animal SPECT system

    Science.gov (United States)

    Chen, Yi-Chun

    A novel small-animal SPECT imager, FastSPECT II, was recently developed at the Center for Gamma-Ray Imaging. FastSPECT II consists of two rings of eight modular scintillation cameras and list-mode data-acquisition electronics that enable stationary and dynamic imaging studies. The instrument is equipped with exchangeable aperture assemblies and adjustable camera positions for selections of magnifications, pinhole sizes, and fields of view (FOVs). The purpose of SPECT imaging is to recover the radiotracer distribution in the object from the measured image data. Accurate knowledge of the imaging system matrix (referred to as H) is essential for image reconstruction. To assure that all of the system physics is contained in the matrix, experimental calibration methods for the individual cameras and the whole imaging system were developed and carefully performed. The average spatial resolution over the FOV of FastSPECT II in its low-magnification (2.4X) configuration is around 2.4 mm, computed from the Fourier crosstalk matrix. The system sensitivity measured with a 99mTc point source at the center of the FOV is about 267 cps/MBq. The system detectability was evaluated by computing the ideal-observer performance on SKE/BKE (signal-known-exactly/background-known-exactly) detection tasks. To reduce the system-calibration time and achieve finer reconstruction grids, two schemes for interpolating H were implemented and compared: these are centroid interpolation with Gaussian fitting and Fourier interpolation. Reconstructed phantom and mouse-cardiac images demonstrated the effectiveness of the H-matrix interpolation. Tomographic reconstruction can be formulated as a linear inverse problem and solved using statistical-estimation techniques. Several iterative reconstruction algorithms were introduced, including maximum-likelihood expectation-maximization (ML-EM) and its ordered-subsets (OS) version, and some least-squares (LS) and weighted-least-squares (WLS) algorithms such

  13. Accuracy improvement in a calibration test bench for accelerometers by a vision system

    Science.gov (United States)

    D'Emilia, Giulio; Di Gasbarro, David; Gaspari, Antonella; Natale, Emanuela

    2016-06-01

    A procedure is described in this paper for the accuracy improvement of calibration of low-cost accelerometers in a prototype rotary test bench, driven by a brushless servo-motor and operating in a low frequency range of vibrations (0 to 5 Hz). Vibration measurements by a vision system based on a low frequency camera have been carried out, in order to reduce the uncertainty of the real acceleration evaluation at the installation point of the sensor to be calibrated. A preliminary test device has been realized and operated in order to evaluate the metrological performances of the vision system, showing a satisfactory behavior if the uncertainty measurement is taken into account. A combination of suitable settings of the control parameters of the motion control system and of the information gained by the vision system allowed to fit the information about the reference acceleration at the installation point to the needs of the procedure for static and dynamic calibration of three-axis accelerometers.

  14. Calibration of dual-energy gamma systems for determining liquid saturations during multiphase flow in soil

    Energy Technology Data Exchange (ETDEWEB)

    Bali, K.M.; Grismer, M.E. [University of California, Cooperative Extension and University of California, Holtville (United States)

    1994-12-31

    The purpose of this study was to calibrate a dual-energy gamma system for simultaneous determination of aqueous and non-aqueous phase liquid (NAPL) in soil column. A dual energy gamma system containing {sup 241}Am and {sup 137}Cs was used to study the infiltration and displacement of aqueous liquid by NAPL and vice versa. Distilled water and Nal solution, and Soltrol 130 were used as fluids. The system was calibrated to minimize errors in liquid saturations due to random nature of gamma photons emission and drift in the photon detection equipment. The measurement accuracy in liquid saturations was substantially improved by increasing counting time and fluid attenuation coefficient. Nal salt was used to increase the attenuation coefficient of water. Measured and predicted liquid saturation during immiscible displacement in soil were consistent with mass balance measurements and anticipated deviations in saturations from probable error calculations. The calibration procedure resulted in a significant improvement in the prediction of liquid saturation using dual-energy gamma system. (author). 8 refs, 4 tabs.

  15. A novel single-step, multipoint calibration method for instrumented Lab-on-Chip systems

    DEFF Research Database (Denmark)

    Pfreundt, Andrea; Patou, François; Zulfiqar, Azeem

    2014-01-01

    Despite recent and substantial advances in biosensing, information and communication, and Lab-on-Chip (LoC) technologies, the success of Point-of-Care (PoC) diagnostics and monitoring systems is still challenged by stringent requirements for robustness, cost-effectiveness, and system integration...... specifically addresses the important interfaces between a novel microfluidic unit to integrate the sensor array and a mobile-device hardware accessory. A multi-point calibration curve is obtained by generating a defined set of reference concentrations from a single input. By consecutively splitting the flow...... perpendicular to the diffusion interface only one mixing step is required for each of the generated calibration solutions. This results in a compact design with a very small footprint of the microfluidic layout....

  16. Drive system alignment calibration of a microgravity drop tower of novel design

    Science.gov (United States)

    Trunins, J.; Osborne, B. P.; Augousti, A.

    2013-06-01

    We report here the calibration of the drive system of a new scientific facility for production of microgravity, operating on a novel design of electromagnetically driven platform. The construction achieves the design specification of alignment of the guide rails to better than 0.254mm across the entire guide rail height of 8m, despite a small lean to the right (within tolerance) and it was noted that this alignment is improved by the presence of the trolley that carries the platform.

  17. Temporal Analysis and Automatic Calibration of the Velodyne HDL-32E LiDAR System

    Science.gov (United States)

    Chan, T. O.; Lichti, D. D.; Belton, D.

    2013-10-01

    At the end of the first quarter of 2012, more than 600 Velodyne LiDAR systems had been sold worldwide for various robotic and high-accuracy survey applications. The ultra-compact Velodyne HDL-32E LiDAR has become a predominant sensor for many applications that require lower sensor size/weight and cost. For high accuracy applications, cost-effective calibration methods with minimal manual intervention are always desired by users. However, the calibrations are complicated by the Velodyne LiDAR's narrow vertical field of view and the very highly time-variant nature of its measurements. In the paper, the temporal stability of the HDL-32E is first analysed as the motivation for developing a new, automated calibration method. This is followed by a detailed description of the calibration method that is driven by a novel segmentation method for extracting vertical cylindrical features from the Velodyne point clouds. The proposed segmentation method utilizes the Velodyne point cloud's slice-like nature and first decomposes the point clouds into 2D layers. Then the layers are treated as 2D images and are processed with the Generalized Hough Transform which extracts the points distributed in circular patterns from the point cloud layers. Subsequently, the vertical cylindrical features can be readily extracted from the whole point clouds based on the previously extracted points. The points are passed to the calibration that estimates the cylinder parameters and the LiDAR's additional parameters simultaneously by constraining the segmented points to fit to the cylindrical geometric model in such a way the weighted sum of the adjustment residuals are minimized. The proposed calibration is highly automatic and this allows end users to obtain the time-variant additional parameters instantly and frequently whenever there are vertical cylindrical features presenting in scenes. The methods were verified with two different real datasets, and the results suggest that up to 78

  18. Thermal modeling of a secondary concentrator integrated with an open direct-absorption molten-salt volumetric receiver in a beam-down tower system

    Science.gov (United States)

    Lahlou, Radia; Armstrong, Peter; Grange, Benjamin; Almheiri, Saif; Calvet, Nicolas; Slocum, Alexander; Shamim, Tariq

    2016-05-01

    An upward-facing three-dimensional secondary concentrator, herein termed Final Optical Element (FOE), is designed to be used in a beam-down tower in combination with an open volumetric direct-absorption molten-salt receiver tank acting simultaneously as a thermal energy storage system. It allows reducing thermal losses from the open receiver by decreasing its aperture area while keeping minimal spillage losses. The FOE is exposed to high solar fluxes, a part of which is absorbed by its reflector material, leading to material degradation by overheating. Consequently, the FOE may require active cooling. A thermal model of the FOE under passive cooling mechanism is proposed as a first step to evaluate its sensitivity to some design parameters. Then, it will be used to evaluate the requirements for the active cooling system. The model provides insights on the FOE thermal behavior and highlights the effectiveness of a design modification on passive cooling enhancement. First prototype tests under reduced flux and with no active cooling will be used for model adjustment.

  19. Calibration of Thermal Desorption System (TDS) Response to Hydrogen for Analysis of Titanium Subhydride and Titanium Hydride

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Bernice E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2013-07-01

    The equipment and method for and results of calibration of the Sandia/CA TDS system for hydrogen quantification is presented. This technique for calibration can be used to quantify the hydrogen content titanium subhydride, titanium hydride, and any other hydrogen-containing material that desorbs its hydrogen in the form of molecular hydrogen below 1450°C.

  20. Geometric calibration of multi-sensor image fusion system with thermal infrared and low-light camera

    Science.gov (United States)

    Peric, Dragana; Lukic, Vojislav; Spanovic, Milana; Sekulic, Radmila; Kocic, Jelena

    2014-10-01

    A calibration platform for geometric calibration of multi-sensor image fusion system is presented in this paper. The accurate geometric calibration of the extrinsic geometric parameters of cameras that uses planar calibration pattern is applied. For calibration procedure specific software is made. Patterns used in geometric calibration are prepared with aim to obtain maximum contrast in both visible and infrared spectral range - using chessboards which fields are made of different emissivity materials. Experiments were held in both indoor and outdoor scenarios. Important results of geometric calibration for multi-sensor image fusion system are extrinsic parameters in form of homography matrices used for homography transformation of the object plane to the image plane. For each camera a corresponding homography matrix is calculated. These matrices can be used for image registration of images from thermal and low light camera. We implemented such image registration algorithm to confirm accuracy of geometric calibration procedure in multi-sensor image fusion system. Results are given for selected patterns - chessboard with fields made of different emissivity materials. For the final image registration algorithm in surveillance system for object tracking we have chosen multi-resolution image registration algorithm which naturally combines with a pyramidal fusion scheme. The image pyramids which are generated at each time step of image registration algorithm may be reused at the fusion stage so that overall number of calculations that must be performed is greatly reduced.

  1. The upgrade of the laser calibration system for the ATLAS hadron calorimeter TileCal

    CERN Document Server

    Spalla, Margherita; The ATLAS collaboration

    2014-01-01

    The Tile Calorimeter (TileCal), the central section of the hadronic calorimeter of the ATLAS experiment, is a key detector component to detect hadrons, jets and taus and to measure the missing transverse energy. TileCal is built of steel and scintillating tiles coupled to optical fibers and read‐out by photomultipliers (PMT). The performance of TileCal relies on a continuous, high resolution calibration of the individual response of the 10,000 channels forming the detector. The calibration is based on a three level architecture: a charge injection system used to monitor the full electronics chain including front-end amplifiers, digitizers and event builder blocks for each individual channel; a distributed optical system using laser pulses to excite all PMTs; and a mobile Cesium radiative source which is driven through the detector cell floating inside a pipe system. This architecture allows for a cascade calibration of the electronics, of the PMT and electronics, and of full chain including the active detec...

  2. A laser diode based system for calibration of fast time-of-flight detectors

    CERN Document Server

    Bonesini, M; deBari, A; Rossella, M

    2016-01-01

    A system based on commercially available items, such as a laser diode, emitting in the visible range $\\sim 400$ nm,and multimode fiber patches, fused fiber splitters and optical switches may be assembled,for time calibration of multi-channels time-of-flight (TOF) detectors with photomultipliers' (PMTs') readout. As available laser diode sources have unfortunately limited peak power, the main experimental problem is the tight light power budget of such a system. In addition, while the technology for fused fiber splitters is common in the Telecom wavelength range ($\\lambda \\sim 850, 1300-1500$ nm), it is not easily available in the visible one. Therefore, extensive laboratory tests had to be done on purpose, to qualify the used optical components, and a full scale timing calibration prototype was built. Obtained results show that with such a system, a calibration resolution ($\\sigma$) in the range 20-30 ps may be within reach. Therefore, fast multi-channels TOF detectors, with timing resolutions in the range 50...

  3. Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System

    Directory of Open Access Journals (Sweden)

    Yu Lu

    2016-04-01

    Full Text Available A new compact large field of view (FOV multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second.

  4. Intelligent pulse light source in the performance calibration system of two-dimensional neutron detector

    Science.gov (United States)

    Yang, Lei; Zhao, Xiao-Fang

    2017-07-01

    Chinese Spallation Neutron Source (CSNS) project will use numerous two-dimensional (2D) neutron detectors whose ZnS (Ag) scintillator is doped with 6Li. To ensure the consistency of all neutron detectors, a calibration system for the performance of 2D neutron detectors is designed. For radiation protection, the state control of the radiation source gets more and more strict. It is impossible to directly carry out experiments with massive radioactive particles. Thus, the following scheme has been designed. The controlled pulsed laser light source on a 2D mobile platform is used to replace the neutron bombardment to generate the photon. The pulse signal drives the laser diode to generate pulse light. The pulse light source located on the 2D platform is controlled by the core controller, and goes to the wavelength shift fiber through the optical fiber. The host computer (PC) receives the signal from the electronics system, processes data, and automatically calibrates the performance parameters. As shown by the experimental results, the pulse light source can perfectly meet all requirements of 2D neutron detector calibration system.

  5. Utilization of a Terrestrial Laser Scanner for the Calibration of Mobile Mapping Systems.

    Science.gov (United States)

    Hong, Seunghwan; Park, Ilsuk; Lee, Jisang; Lim, Kwangyong; Choi, Yoonjo; Sohn, Hong-Gyoo

    2017-02-27

    This paper proposes a practical calibration solution for estimating the boresight and lever-arm parameters of the sensors mounted on a Mobile Mapping System (MMS). On our MMS devised for conducting the calibration experiment, three network video cameras, one mobile laser scanner, and one Global Navigation Satellite System (GNSS)/Inertial Navigation System (INS) were mounted. The geometric relationships between three sensors were solved by the proposed calibration, considering the GNSS/INS as one unit sensor. Our solution basically uses the point cloud generated by a 3-dimensional (3D) terrestrial laser scanner rather than using conventionally obtained 3D ground control features. With the terrestrial laser scanner, accurate and precise reference data could be produced and the plane features corresponding with the sparse mobile laser scanning data could be determined with high precision. Furthermore, corresponding point features could be extracted from the dense terrestrial laser scanning data and the images captured by the video cameras. The parameters of the boresight and the lever-arm were calculated based on the least squares approach and the precision of the boresight and lever-arm could be achieved by 0.1 degrees and 10 mm, respectively.

  6. Photometric Calibration and Image Stitching for a Large Field of View Multi-Camera System.

    Science.gov (United States)

    Lu, Yu; Wang, Keyi; Fan, Gongshu

    2016-04-11

    A new compact large field of view (FOV) multi-camera system is introduced. The camera is based on seven tiny complementary metal-oxide-semiconductor sensor modules covering over 160° × 160° FOV. Although image stitching has been studied extensively, sensor and lens differences have not been considered in previous multi-camera devices. In this study, we have calibrated the photometric characteristics of the multi-camera device. Lenses were not mounted on the sensor in the process of radiometric response calibration to eliminate the influence of the focusing effect of uniform light from an integrating sphere. Linearity range of the radiometric response, non-linearity response characteristics, sensitivity, and dark current of the camera response function are presented. The R, G, and B channels have different responses for the same illuminance. Vignetting artifact patterns have been tested. The actual luminance of the object is retrieved by sensor calibration results, and is used to blend images to make panoramas reflect the objective luminance more objectively. This compensates for the limitation of stitching images that are more realistic only through the smoothing method. The dynamic range limitation of can be resolved by using multiple cameras that cover a large field of view instead of a single image sensor with a wide-angle lens. The dynamic range is expanded by 48-fold in this system. We can obtain seven images in one shot with this multi-camera system, at 13 frames per second.

  7. Determination of the analytical performance of a headspace capillary gas chromatographic technique and karl Fischer coulometric titration by system calibration using oil samples containing known amounts of moisture.

    Science.gov (United States)

    Jalbert, J; Gilbert, R; Tétreault, P

    1999-08-01

    Over the past few years, concerns have been raised in the literature about the accuracy of the Karl Fischer (KF) method for assessing moisture in transformer mineral oils. To better understand this issue, the performance of a static headspace capillary gas chromatographic (HS-CGC) technique was compared to that of KF coulometric titration by analyzing moisture in samples containing known amounts of water and various samples obtained from the National Institute of Standards and Technology (NIST). Two modes of adding samples into the KF vessel were used:  direct injection and indirect injection via an azeotropic distillation of the moisture with toluene. Under the conditions used for direct injection, the oil matrix was totally dissolved in the anolyte, which allowed the moisture to be titrated in a single-phase solution rather than in a suspension. The results have shown that when HS-CGC and combined azeotropic distillation/KF titration are calibrated with moisture-in-oil standards, a linear relation is observed over 0-60 ppm H(2)O with a correlation coefficient better than 0.9994 (95% confidence), with the regression line crossing through zero. A similar relation can also be observed when calibration is achieved by direct KF addition of standards prepared with octanol-1, but in this case an intercept of 4-5 ppm is noted. The amount of moisture determined by curve interpolation in NIST reference materials by the three calibrated systems ranges from 13.0 to 14.8 ppm for RM 8506 and 42.5 to 46.4 ppm for RM 8507, and in any case, the results were as high as those reported in the literature with volumetric KF titration. However, titration of various dehydrated oil and solvent samples showed that direct KF titration is affected by a small bias when samples contain very little moisture. The source of error after correction for the large sample volume used for the determination (8 mL) is about 6 ppm for Voltesso naphthenic oil and 4 ppm for toluene, revealing a matrix

  8. SU-E-T-268: Differences in Treatment Plan Quality and Delivery Between Two Commercial Treatment Planning Systems for Volumetric Arc-Based Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S; Zhang, H; Zhang, B; D’Souza, W [University of Maryland School of Medicine, Baltimore, MD (United States)

    2015-06-15

    Purpose: To clinically evaluate the differences in volumetric modulated arc therapy (VMAT) treatment plan and delivery between two commercial treatment planning systems. Methods: Two commercial VMAT treatment planning systems with different VMAT optimization algorithms and delivery approaches were evaluated. This study included 16 clinical VMAT plans performed with the first system: 2 spine, 4 head and neck (HN), 2 brain, 4 pancreas, and 4 pelvis plans. These 16 plans were then re-optimized with the same number of arcs using the second treatment planning system. Planning goals were invariant between the two systems. Gantry speed, dose rate modulation, MLC modulation, plan quality, number of monitor units (MUs), VMAT quality assurance (QA) results, and treatment delivery time were compared between the 2 systems. VMAT QA results were performed using Mapcheck2 and analyzed with gamma analysis (3mm/3% and 2mm/2%). Results: Similar plan quality was achieved with each VMAT optimization algorithm, and the difference in delivery time was minimal. Algorithm 1 achieved planning goals by highly modulating the MLC (total distance traveled by leaves (TL) = 193 cm average over control points per plan), while maintaining a relatively constant dose rate (dose-rate change <100 MU/min). Algorithm 2 involved less MLC modulation (TL = 143 cm per plan), but greater dose-rate modulation (range = 0-600 MU/min). The average number of MUs was 20% less for algorithm 2 (ratio of MUs for algorithms 2 and 1 ranged from 0.5-1). VMAT QA results were similar for all disease sites except HN plans. For HN plans, the average gamma passing rates were 88.5% (2mm/2%) and 96.9% (3mm/3%) for algorithm 1 and 97.9% (2mm/2%) and 99.6% (3mm/3%) for algorithm 2. Conclusion: Both VMAT optimization algorithms achieved comparable plan quality; however, fewer MUs were needed and QA results were more robust for Algorithm 2, which more highly modulated dose rate.

  9. A Calibration Method Based on Linear InGaAs in Fiber Grating Sensors Interrogation System

    Institute of Scientific and Technical Information of China (English)

    TAO Jun; ZHANG Xia

    2009-01-01

    In accordance with the characteristics of wavelength shift detection in fiber grating sensor interrogation system, the wavelength interrogation system which uses linear InGaAs as the spectrum receiver is proposed. Orientation of optic spectrum line affects the silt of volume phase grating and size of InGaAs photosensitive unit, thus the calibration method is needed. Based on an analysis of InGaAs imaging model, least square curve fitting method is proposed to detect spectrum wavelength and InGaAs photosensitive unit position. The experimental results show that the methods are effective and the demodulation system precision is improved.

  10. Flow Forecasting in Drainage Systems with Extrapolated Radar Rainfall Data and Auto Calibration on Flow Observations

    DEFF Research Database (Denmark)

    Thorndahl, Søren Liedtke; Grum, M.; Rasmussen, Michael R.;

    2011-01-01

    in a small urban catchment has been developed. The forecast is based on application of radar rainfall data, which by a correlation based technique, is extrapolated with a lead time up to two hours. The runoff forecast in the drainage system is based on a fully distributed MOUSE model which is auto......Forecasting of flows, overflow volumes, water levels, etc. in drainage systems can be applied in real time control of drainage systems in the future climate in order to fully utilize system capacity and thus save possible construction costs. An online system for forecasting flows and water levels......-calibrated on flow measurements in order to produce the best possible forecast for the drainage system at all times. The system shows great potential for the implementation of real time control in drainage systems and forecasting flows and water levels....

  11. High-resolution Volumetric Display System with Multi-screen in Parallel Motion%高分辨率多屏平动体积显示系统

    Institute of Scientific and Technical Information of China (English)

    李立新; 夏孙城; 沈海锋; 江玉刚

    2012-01-01

    A high-resolution volumetric display system by scanning with multi-screen in parallel motion and a corresponding principle prototype is described. Through a DMD, 2D image sequence is projected on imaging screens moving in circular translation, and the dynamic refreshed image sequence is perceived as a 3D image with physical depth because of the persistence of vision. The optical projecting module keeps the optical path between the projector and the imaging screen to be constant. Hence, a clear and stable image space is constructed. A high-speed data channel is designed on a FPGA chip, whose bandwidth achieves 18.75 Gbps. Each volumetric frame contains 512 frames and over 400 million voxels at 12 Hz refresh frequency. The principle prototype is successfully manufactured, and the 3D display effect is achieved as anticipated.%描述了一种基于多屏平动扫描的高分辨率体积显示系统及其原理样机.通过DMD向多个圆周平动的成像屏投射二维图像序列,借助人眼视觉暂留效应,此动态刷新的二维图像序列被感知为一个具有物理景深的三维图像.其光学投影模块保证了投影仪与成像屏之间的光程不变,从而构建了清晰稳定的成像空间;采用FPGA设计高速数据通道,带宽达到了18.75 Gbps,使得每个三维体积帧包含512个二维图像切片,总体素超过4亿,刷新频率达到12Hz.成功研制了原理样机,达到了预期的三维显示效果.

  12. CALIBRATION ERRORS IN THE CAVITY BEAM POSITION MONITOR SYSTEM AT THE ATF2

    CERN Document Server

    Cullinan, F; Joshi, N; Lyapin, A

    2011-01-01

    It has been shown at the Accelerator Test Facility at KEK, that it is possible to run a system of 37 cavity beam position monitors (BPMs) and achieve high working resolution. However, stability of the calibration constants (position scale and radio frequency (RF) phase) over a three/four week running period is yet to be demonstrated. During the calibration procedure, random beam jitter gives rise to a statistical error in the position scale and slow orbit drift in position and tilt causes systematic errors in both the position scale and RF phase. These errors are dominant and have been evaluated for each BPM. The results are compared with the errors expected after a tested method of beam jitter subtraction has been applied.

  13. Commissioning of an LED calibration and monitoring system for the prototype of a hadronic calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Wattimena, N.

    2006-12-15

    The anticipated physics program for the International Linear Collider (ILC) requires a highly granular hadronic calorimeter. One option for such a tracking calorimeter is a scintillator-steel sandwich structure placed inside the magnetic coil. The development of hadronic showers will be studied with a physics prototype, in order to improve current models. This prototype, currently being built within the collaboration for a CAlorimeter for the LInear Collider Experiment (CALICE) at the Deutsches Elektronen-Synchrotron (DESY) also serves to test a new semiconductor based photodetector the so called silicon photomultiplier. The calibration of these new photodetectors requires to take into account their nonlinear response.The response function, describing this behaviour, is investigated in this thesis. A calibration and monitoring system, needed to correct for the temperature and voltage dependence of the silicon photomultiplier signals and to observe changes of their response over time, is optimised and tested. (orig.)

  14. Optical configuration optimization and calibration for the POINT system on EAST

    Science.gov (United States)

    Zou, Z. Y.; Liu, H. Q.; Li, W. M.; Lian, H.; Wang, S. X.; Yao, Y.; Lan, T.; Zeng, L.; Jie, Y. X.

    2016-11-01

    Calibration of the polarimeter system is one of the key elements to determine the overall measurement accuracy. The anisotropic reflection and transmission properties of the mesh beam splitters can easily distort the polarization state of the circularly polarized beams. Using a rotating crystal quartz λ/2-waveplate to replace the plasma can effectively allow us to obtain the ratio of the measured Faraday rotation angle to the known rotation angle of the waveplate. This ratio is used to estimate the calibration factor for each chord to be accurately determined and help to minimize distortions introduced by the wire-mesh beam splitters. With the novel configuration optimization, the distortion of polarization state is effectively eliminated.

  15. Object Occlusion Detection Using Automatic Camera Calibration for a Wide-Area Video Surveillance System

    Directory of Open Access Journals (Sweden)

    Jaehoon Jung

    2016-06-01

    Full Text Available This paper presents an object occlusion detection algorithm using object depth information that is estimated by automatic camera calibration. The object occlusion problem is a major factor to degrade the performance of object tracking and recognition. To detect an object occlusion, the proposed algorithm consists of three steps: (i automatic camera calibration using both moving objects and a background structure; (ii object depth estimation; and (iii detection of occluded regions. The proposed algorithm estimates the depth of the object without extra sensors but with a generic red, green and blue (RGB camera. As a result, the proposed algorithm can be applied to improve the performance of object tracking and object recognition algorithms for video surveillance systems.

  16. Object Occlusion Detection Using Automatic Camera Calibration for a Wide-Area Video Surveillance System.

    Science.gov (United States)

    Jung, Jaehoon; Yoon, Inhye; Paik, Joonki

    2016-06-25

    This paper presents an object occlusion detection algorithm using object depth information that is estimated by automatic camera calibration. The object occlusion problem is a major factor to degrade the performance of object tracking and recognition. To detect an object occlusion, the proposed algorithm consists of three steps: (i) automatic camera calibration using both moving objects and a background structure; (ii) object depth estimation; and (iii) detection of occluded regions. The proposed algorithm estimates the depth of the object without extra sensors but with a generic red, green and blue (RGB) camera. As a result, the proposed algorithm can be applied to improve the performance of object tracking and object recognition algorithms for video surveillance systems.

  17. EAST-AIA deployment under vacuum: Calibration of laser diagnostic system using computer vision

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang, E-mail: yangyang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, 350 Shushanhu Rd, Hefei, Anhui (China); Song, Yuntao; Cheng, Yong; Feng, Hansheng; Wu, Zhenwei; Li, Yingying; Sun, Yongjun; Zheng, Lei [Institute of Plasma Physics, Chinese Academy of Sciences, 350 Shushanhu Rd, Hefei, Anhui (China); Bruno, Vincent; Eric, Villedieu [CEA-IRFM, F-13108 Saint-Paul-Lez-Durance (France)

    2016-11-15

    Highlights: • The first deployment of the EAST articulated inspection arm robot under vacuum is presented. • A computer vision based approach to measure the laser spot displacement is proposed. • An experiment on the real EAST tokamak is performed to validate the proposed measure approach, and the results shows that the measurement accuracy satisfies the requirement. - Abstract: For the operation of EAST tokamak, it is crucial to ensure that all the diagnostic systems are in the good condition in order to reflect the plasma status properly. However, most of the diagnostic systems are mounted inside the tokamak vacuum vessel, which makes them extremely difficult to maintain under high vacuum condition during the tokamak operation. Thanks to a system called EAST articulated inspection arm robot (EAST-AIA), the examination of these in-vessel diagnostic systems can be performed by an embedded camera carried by the robot. In this paper, a computer vision algorithm has been developed to calibrate a laser diagnostic system with the help of a monocular camera at the robot end. In order to estimate the displacement of the laser diagnostic system with respect to the vacuum vessel, several visual markers were attached to the inner wall. This experiment was conducted both on the EAST vacuum vessel mock-up and the real EAST tokamak under vacuum condition. As a result, the accuracy of the displacement measurement was within 3 mm under the current camera resolution, which satisfied the laser diagnostic system calibration.

  18. Supercal: Cross-Calibration of Multiple Photometric Systems to Improve Cosmological Measurements with Type Ia Supernovae

    CERN Document Server

    Scolnic, D; Riess, A G; Rest, A; Schlafly, E; Foley, R J; Finkbeiner, D; Tang, C; Burgett, W S; Chambers, K C; Draper, P W; Hodapp, K W; Huber, M E; Kaiser, N; Kudritzki, R P; Magnier, E A; Metcalfe, N; Stubbs, C W

    2015-01-01

    Current cosmological analyses which use Type Ia supernova (SN Ia) observations combine SN samples to expand the redshift range beyond that of a single sample and increase the overall sample size. The inhomogeneous photometric calibration between different SN samples is one of the largest systematic uncertainties of the cosmological parameter estimation. To place these different samples on a single system, analyses currently use observations of a small sample of very bright flux standards on the $HST$ system. We propose a complementary method, called `Supercal', in which we use measurements of secondary standards in each system, compare these to measurements of the same stars in the Pan-STARRS1 (PS1) system, and determine offsets for each system relative to PS1, placing all SN observations on a single, consistent photometric system. PS1 has observed $3\\pi$ of the sky and has a relative calibration of better than 5 mmag (for $\\sim15system. We use this process t...

  19. Robot tracking system improvements and visual calibration of orbiter position for radiator inspection

    Science.gov (United States)

    Tonkay, Gregory

    1990-01-01

    The following separate topics are addressed: (1) improving a robotic tracking system; and (2) providing insights into orbiter position calibration for radiator inspection. The objective of the tracking system project was to provide the capability to track moving targets more accurately by adjusting parameters in the control system and implementing a predictive algorithm. A computer model was developed to emulate the tracking system. Using this model as a test bed, a self-tuning algorithm was developed to tune the system gains. The model yielded important findings concerning factors that affect the gains. The self-tuning algorithms will provide the concepts to write a program to automatically tune the gains in the real system. The section concerning orbiter position calibration provides a comparison to previous work that had been performed for plant growth. It provided the conceptualized routines required to visually determine the orbiter position and orientation. Furthermore, it identified the types of information which are required to flow between the robot controller and the vision system.

  20. Calibration method of the time synchronization error of many data acquisition nodes in the chained system

    Science.gov (United States)

    Jiang, Jia-jia; Duan, Fa-jie; Chen, Jin; Zhang, Chao; Wang, Kai; Chang, Zong-jie

    2012-08-01

    Time synchronization is very important in a distributed chained seismic acquisition system with a large number of data acquisition nodes (DANs). The time synchronization error has two causes. On the one hand, there is a large accumulated propagation delay when commands propagate from the analysis and control system to multiple distant DANs, which makes it impossible for different DANs to receive the same command synchronously. Unfortunately, the propagation delay of commands (PDCs) varies in different application environments. On the other hand, the phase jitter of both the master clock and the clock recovery phase-locked loop, which is designed to extract the timing signal, may also cause the time synchronization error. In this paper, in order to achieve accurate time synchronization, a novel calibration method is proposed which can align the PDCs of all of the DANs in real time and overcome the time synchronization error caused by the phase jitter. Firstly, we give a quantitative analysis of the time synchronization error caused by both the PDCs and the phase jitter. Secondly, we propose a back and forth model (BFM) and a transmission delay measurement method (TDMM) to overcome these difficulties. Furthermore, the BFM is designed as the hardware configuration to measure the PDCs and calibrate the time synchronization error. The TDMM is used to measure the PDCs accurately. Thirdly, in order to overcome the time synchronization error caused by the phase jitter, a compression and mapping algorithm (CMA) is presented. Finally, based on the proposed BFM, TDMM and CMA, a united calibration algorithm is developed to overcome the time synchronization error caused by both the PDCs and the phase jitter. The simulation experiment results show the effectiveness of the calibration method proposed in this paper.

  1. Measuring the electrical properties of soil using a calibrated ground-coupled GPR system

    Science.gov (United States)

    Oden, C.P.; Olhoeft, G.R.; Wright, D.L.; Powers, M.H.

    2008-01-01

    Traditional methods for estimating vadose zone soil properties using ground penetrating radar (GPR) include measuring travel time, fitting diffraction hyperbolae, and other methods exploiting geometry. Additional processing techniques for estimating soil properties are possible with properly calibrated GPR systems. Such calibration using ground-coupled antennas must account for the effects of the shallow soil on the antenna's response, because changing soil properties result in a changing antenna response. A prototype GPR system using ground-coupled antennas was calibrated using laboratory measurements and numerical simulations of the GPR components. Two methods for estimating subsurface properties that utilize the calibrated response were developed. First, a new nonlinear inversion algorithm to estimate shallow soil properties under ground-coupled antennas was evaluated. Tests with synthetic data showed that the inversion algorithm is well behaved across the allowed range of soil properties. A preliminary field test gave encouraging results, with estimated soil property uncertainties (????) of ??1.9 and ??4.4 mS/m for the relative dielectric permittivity and the electrical conductivity, respectively. Next, a deconvolution method for estimating the properties of subsurface reflectors with known shapes (e.g., pipes or planar interfaces) was developed. This method uses scattering matrices to account for the response of subsurface reflectors. The deconvolution method was evaluated for use with noisy data using synthetic data. Results indicate that the deconvolution method requires reflected waves with a signal/noise ratio of about 10:1 or greater. When applied to field data with a signal/noise ratio of 2:1, the method was able to estimate the reflection coefficient and relative permittivity, but the large uncertainty in this estimate precluded inversion for conductivity. ?? Soil Science Society of America.

  2. Volumetric soft tissue brain imaging on xCAT, a mobile flat-panel x-ray CT system

    Science.gov (United States)

    Zbijewski, Wojciech; Stayman, J. Webster

    2009-02-01

    We discuss the ongoing development of soft-tissue imaging capabilities on xCAT, a highly portable, flat-panel based cone-beam X-ray CT platform. By providing the ability to rapidly detect intra-cranial bleeds and other symptoms of stroke directly at the patient's bedside, our new system can potentially significantly improve the management of neurological emergency and intensive care patients. The paper reports on the design of our system, as well as on the methods used to combat artifacts due to scatter, non-linear detector response and scintillator glare. Images of cadaveric head samples are also presented and compared with conventional CT scans.

  3. In-office rapid volumetric ablation of uterine fibroids under ultrasound imaging guidance: Preclinical and early clinical experience with the Mirabilis transabdominal HIFU treatment system

    Science.gov (United States)

    Leal, José G. Garza; León, Ivan Hernandez; Sáenz, Lorena Castillo; Aguirre, Juan M. Aguilar; Lagos, Joel J. Islas; Parsons, Jessica E.; Darlington, Gregory P.; Lau, Michael P. H.

    2017-03-01

    Mirabilis Medica, Inc. (Bothell, WA, USA) has developed a high-intensity focused ultrasound (HIFU) system for producing rapid transabdominal volumetric ablation of uterine fibroids in an office-based setting. The Mirabilis HIFU Treatment System utilizes integrated ultrasound imaging guidance and short treatment times under 15 minutes. Treatment with the Mirabilis system is generally well tolerated using only oral analgesia without anesthesia or sedation. This paper summarizes certain technical aspects of the Mirabilis HIFU technology, the preclinical development process, and the results of the first in-human clinical study using the Mirabilis system. During preclinical studies, an in vivo transcutaneous porcine lower extremity model was used in a total of 180 adult swine to develop the HIFU treatment regimen parameters. Additionally, 108 excised human uteri with fibroids obtained from scheduled hysterectomies were treated in an ex vivo experimental setup and evaluated. These preclinical activities resulted in a HIFU treatment technique referred to as Mirabilis Shell Ablation, which enables rapid volumetric fibroid ablation by directing the HIFU energy to the outer perimeter of the target volume (the `shell') without insonating its core. This method results in efficient fibroid treatment through a synergistic combination of direct tissue ablation, cooperative heating effects, and indirect ischemic necrosis in the interior of the volume. After refining this technique and performing safety testing in the in vivo porcine model, a clinical pilot study was conducted to assess the initial safety and performance of the Mirabilis HIFU Treatment System for transabdominal treatment of uterine fibroids in eligible women who were scheduled to undergo hysterectomy following treatment with the device. A total of 37 women meeting certain eligibility criteria were treated at two clinical sites in Mexico. Twenty-nine (29) of these 37 women received only prophylactic sublingual

  4. The system test of the ZEUS microvertex detector: calibration and digitisation of the detector signals

    Energy Technology Data Exchange (ETDEWEB)

    Adler, V.

    2002-09-01

    During the shut-down of the electron-proton collider HERA at DESY in Hamburg in the years 2000/2001, the new silicon strip vertex detector MVD has been installed into the ZEUS experiment to achieve a higher quality in the reconstruction of particle tracks. Before its installation, the MVD and all associated hard- and software components have been tested. The objectives of this test - the so-called ''system test'' - were to investigate the performance of the detector and to check the stability and interplay of all components and the monitoring systems. In this thesis, the online software to calibrate the detector signals and to store and monitor the calibration parameters has been developed. Furthermore the stability of the calibration parameters over the system test running period has been investigated. In addition, the simulation of the analog detector signals (digitisation) has been worked out, and the simulated signals have been compared with the real detector response. After a short introduction into the HERA collider and the ZEUS experiment in Chap. 1, the principles of silicon strip detectors are exposed in Chap. 2. Chap. 3 describes the layout of the MVD in detail, and an overview of the data acquisition system is given. Some results of previous measurements on single silicon strip detectors of the MVD obtained with an electron test beam, which are relevant for this thesis, are summarised. The aims and the set-up of the system test are described in Chap. 4. Then results of analyses on the system test data are presented, which have been obtained in parallel to the work of this thesis. The calibration of the detector signals is described in detail in Chap. 5. After an introduction into the meaning and the calculation of the calibration parameters, the methods to obtain, monitor and store them are explained. Also an analysis is introduced, which studies the stability of the calibration parameters. Overall 98% of all MVD channels operate

  5. A vision-based self-calibration method for robotic visual inspection systems.

    Science.gov (United States)

    Yin, Shibin; Ren, Yongjie; Zhu, Jigui; Yang, Shourui; Ye, Shenghua

    2013-12-03

    A vision-based robot self-calibration method is proposed in this paper to evaluate the kinematic parameter errors of a robot using a visual sensor mounted on its end-effector. This approach could be performed in the industrial field without external, expensive apparatus or an elaborate setup. A robot Tool Center Point (TCP) is defined in the structural model of a line-structured laser sensor, and aligned to a reference point fixed in the robot workspace. A mathematical model is established to formulate the misalignment errors with kinematic parameter errors and TCP position errors. Based on the fixed point constraints, the kinematic parameter errors and TCP position errors are identified with an iterative algorithm. Compared to the conventional methods, this proposed method eliminates the need for a robot-based-frame and hand-to-eye calibrations, shortens the error propagation chain, and makes the calibration process more accurate and convenient. A validation experiment is performed on an ABB IRB2400 robot. An optimal configuration on the number and distribution of fixed points in the robot workspace is obtained based on the experimental results. Comparative experiments reveal that there is a significant improvement of the measuring accuracy of the robotic visual inspection system.

  6. A robust calibration technique for acoustic emission systems based on momentum transfer from a ball drop

    Science.gov (United States)

    McLaskey, Gregory C.; Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M.

    2015-01-01

    We describe a technique to estimate the seismic moment of acoustic emissions and other extremely small seismic events. Unlike previous calibration techniques, it does not require modeling of the wave propagation, sensor response, or signal conditioning. Rather, this technique calibrates the recording system as a whole and uses a ball impact as a reference source or empirical Green’s function. To correctly apply this technique, we develop mathematical expressions that link the seismic moment $M_{0}$ of internal seismic sources (i.e., earthquakes and acoustic emissions) to the impulse, or change in momentum $\\Delta p $, of externally applied seismic sources (i.e., meteor impacts or, in this case, ball impact). We find that, at low frequencies, moment and impulse are linked by a constant, which we call the force‐moment‐rate scale factor $C_{F\\dot{M}} = M_{0}/\\Delta p$. This constant is equal to twice the speed of sound in the material from which the seismic sources were generated. Next, we demonstrate the calibration technique on two different experimental rock mechanics facilities. The first example is a saw‐cut cylindrical granite sample that is loaded in a triaxial apparatus at 40 MPa confining pressure. The second example is a 2 m long fault cut in a granite sample and deformed in a large biaxial apparatus at lower stress levels. Using the empirical calibration technique, we are able to determine absolute source parameters including the seismic moment, corner frequency, stress drop, and radiated energy of these magnitude −2.5 to −7 seismic events.

  7. Bulk-assay calorimeter: Part 1. System design and operation. Part 2. Calibration and testing

    Energy Technology Data Exchange (ETDEWEB)

    Perry, R.B.; Roche, C.T.; Harkness, A.L.; Winslow, G.H.; Youngdahl, G.A.; Lewis, R.N.; Jung, E.A.

    1982-01-01

    The Bulk-Assay Calorimeter is designed to measure the thermal power emitted by plutonium-containing samples. The sample power range of the instrument is 1.4 to 22.4 W. The instrument package consists of the calorimeter measurement chamber, the control circuit power bin, and the data acquisition system. Two sample preheating chambers and five calorimeter canisters for containing the samples are included. A set of 32 test points which monitor voltages at points within the calorimeter and its control circuitry are accessed by the data acquisition system. The use of the test points is described. System start-up and checkout are described. Sample assay and preheater operation procedures are given. The data acquisition system and data analysis software are described. The calorimeter was calibrated at 23 points with heat sources from 1.4 to 22.4 watts. The combined measurement error varied with sample power from 1.4% to 0.1% over the range of calibration measurements. Circuit diagrams for the calorimeter and schematics for the data acquisition system are included. (LEW)

  8. Electron beam test of key elements of the laser-based calibration system for the muon $g$ $-$ $2$ experiment

    CERN Document Server

    Anastasi, A; Bedeschi, F; Bartolini, M; Cantatore, G; Cauz, D; Corradi, G; Dabagov, S; DI Sciascio, G; Di Stefano, R; Driutti, A; Escalante, O; Ferrari, C; Fienberg, A T; Fioretti, A; Gabbanini, C; Gioiosa, A; Hampai, D; Hertzog, D W; Iacovacci, M; Karuza, M; Kaspar, J; Liedl, A; Luisiani, A; Marignetti, F; Mastroianni, S; Moricciani, D; Pauletta, G; Piacentino, G M; Raha, N; Rossi, E; Santi, L; Venanzoni, G

    2016-01-01

    We report the test of many of the key elements of the laser-based calibration system for muon g - 2 experiment E989 at Fermilab. The test was performed at the Laboratori Nazionali di Frascati's Beam Test Facility using a 450 MeV electron beam impinging on a small subset of the final g - 2 lead-fluoride crystal calorimeter system. The calibration system was configured as planned for the E989 experiment and uses the same type of laser and most of the final optical elements. We show results regarding the calorimeter's response calibration, the maximum equivalent electron energy which can be provided by the laser and the stability of the calibration system components.

  9. Electron beam test of key elements of the laser-based calibration system for the muon g - 2 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Anastasi, A.; Basti, A.; Bedeschi, F.; Bartolini, M.; Cantatore, G.; Cauz, D.; Corradi, G.; Dabagov, S.; Di Sciascio, G.; Di Stefano, R.; Driutti, A.; Escalante, O.; Ferrari, C.; Fienberg, A. T.; Fioretti, A.; Gabbanini, C.; Gioiosa, A.; Hampai, D.; Hertzog, D. W.; Iacovacci, M.; Karuza, M.; Kaspar, J.; Liedl, A.; Lusiani, A.; Marignetti, F.; Mastroianni, S.; Moricciani, D.; Pauletta, G.; Piacentino, G. M.; Raha, N.; Rossi, E.; Santi, L.; Venanzoni, G.

    2017-01-01

    We report the test of many of the key elements of the laser-based calibration system for muon g - 2 experiment E989 at Fermilab. The test was performed at the Laboratori Nazionali di Frascati's Beam Test Facility using a 450 MeV electron beam impinging on a small subset of the final g - 2 lead-fluoride crystal calorimeter system. The calibration system was configured as planned for the E989 experiment and uses the same type of laser and most of the final optical elements. We show results regarding the calorimeter's response calibration, the maximum equivalent electron energy which can be provided by the laser and the stability of the calibration system components.

  10. Continuous calibration of a vacuum ultraviolet system from 65 to 125 nm by a cascade arc and comparison with the calibrated line radiation of a hollow cathode.

    Science.gov (United States)

    Frost, R M; Awakowicz, P

    1997-03-20

    A high-power stationary helium cascade arc has been developed as a standard source for continuum radiation in the VUV spectral range from 65 to 125 nm. The calibration of the VUV system response was based on the calculated and measured continuum radiation of a 2-mmphi pure He arc. Diagnostics of the arc plasma in partial thermal equilibrium yielded the electron density and the temperature that were inserted in the calculations of the continuous radiation. The results were compared with the helium, argon, and krypton radiation lines of a high-current hollow cathode lamp. This lamp was built according to the construction drawings of a hollow cathode, which was calibrated by means of the electron synchrotron radiation at the Physikalisch Technische Bundesanstalt Berlin.

  11. Double-theodolite measurement system used in the image calibration of space photographic instrument

    Institute of Scientific and Technical Information of China (English)

    LI Yan; QIAO Yan-feng; SU Wan-xin; LIU Ze-xun

    2005-01-01

    The purpose of characterizing the image of space photographic instrument is to gain the space included angles from three coordinate axes in the three-dimensional coordinate of the image and the directionality of the three axes of coordinate in the frame of axes of the instrument. The two reference frames will keep in the same direction finally by adjusting according to space angles. This problem was solved by a new high-precision measurement system composed of a double-theodolite and a set of communication system. In the survey system, two TDA5005 total stations from Leica Company will be selected as the double-theodolite and the interdependence of both coordinate systems can be achieved by moving the stations only at one time. Therefore, this measurement system provides a highly efficient and high-precision surveying method to the image calibration of the space photographic instrument. According to the experiment, its measuring accuracy can reach arc-second level.

  12. Data Acquisition and Management in the Calibration Processes of the CMS Barrel Muon Alignment System

    CERN Document Server

    Székely, Géza; Bencze, Gy L; Béni, N; Imrek, J; Molnár, J; Novák, D; Raics, P; Szabó, Z

    2007-01-01

    In order to be able to match correctly the track elements produced by a muon in the Tracker and the Muon System of the CMS experiment [1] the mutual alignment precision between the Tracker and the Barrel Muon System must be no worse than 100-400 micrometers depending on the radial distance of the muon chambers from the Tracker. To fulfill this requirement an alignment system had to be designed. This system contains subsystems for determining the positions of the barrel and endcap chambers while a third one connects these two to the Tracker. Since the Barrel muon chambers are embedded into the magnet yoke of the experiment a nonconventional alignment method had to be developed. In this paper we restrict ourselves to the Barrel Alignment System and the calibration methods of its components.

  13. Volumetric rendering and metrology of spherical gradient refractive index lens imaged by angular scan optical coherence tomography system.

    Science.gov (United States)

    Yao, Jianing; Thompson, Kevin P; Ma, Bin; Ponting, Michael; Rolland, Jannick P

    2016-08-22

    In this paper, we develop the methodology, including the refraction correction, geometrical thickness correction, coordinate transformation, and layer segmentation algorithms, for 3D rendering and metrology of a layered spherical gradient refractive index (S-GRIN) lens based on the imaging data collected by an angular scan optical coherence tomography (OCT) system. The 3D mapping and rendering enables direct 3D visualization and internal defect inspection of the lens. The metrology provides assessment of the surface geometry, the lens thickness, the radii of curvature of the internal layer interfaces, and the misalignment of the internal S-GRIN distribution with respect to the lens surface. The OCT metrology results identify the manufacturing defects, and enable targeted process development for optimizing the manufacturing parameters. The newly fabricated S-GRIN lenses show up to a 7x spherical aberration reduction that allows a significantly increased utilizable effective aperture.

  14. A fiber-optic-based calibration system for the High Resolution Fly's Eye cosmic ray observatory

    Energy Technology Data Exchange (ETDEWEB)

    Girard, J.H.V.; Wiencke, L.R. E-mail: wiencke@cosmic.utah.edu; Archbold, G.C.; Bellido, J.A.; Belov, K.; Boyer, J.H.; Everett, A.A.; Gray, R.C.; Jui, C.C.H.; Knapp, B.C.; Mannel, E.J.; Matthews, J.N.; Moore, S.A.; Mumford, J.R.; Roberts, M.D.; Shen, P.; Sokolsky, P.V.; Springer, R.W.; Thomas, S.B

    2001-03-21

    This article describes the fiber-optic-based calibration system installed at the High Resolution Fly's Eye (HiRes) astro-particle physics observatory. The HiRes detectors measure ultra violet scintillation light from distant extensive air showers. This automated calibration system delivers light from a frequency tripled 355 nm YAG laser to the 10,752 photo-multiplier tubes of the 42 HiRes-II detectors.

  15. Development of Rapid, Continuous Calibration Techniques and Implementation as a Prototype System for Civil Engineering Materials Evaluation

    Science.gov (United States)

    Scott, M. L.; Gagarin, N.; Mekemson, J. R.; Chintakunta, S. R.

    2011-06-01

    Until recently, civil engineering material calibration data could only be obtained from material sample cores or via time consuming, stationary calibration measurements in a limited number of locations. Calibration data are used to determine material propagation velocities of electromagnetic waves in test materials for use in layer thickness measurements and subsurface imaging. Limitations these calibration methods impose have been a significant impediment to broader use of nondestructive evaluation methods such as ground-penetrating radar (GPR). In 2006, a new rapid, continuous calibration approach was designed using simulation software to address these measurement limitations during a Federal Highway Administration (FHWA) research and development effort. This continuous calibration method combines a digitally-synthesized step-frequency (SF)-GPR array and a data collection protocol sequence for the common midpoint (CMP) method. Modeling and laboratory test results for various data collection protocols and materials are presented in this paper. The continuous-CMP concept was finally implemented for FHWA in a prototype demonstration system called the Advanced Pavement Evaluation (APE) system in 2009. Data from the continuous-CMP protocol is processed using a semblance/coherency analysis to determine material propagation velocities. Continuously calibrated pavement thicknesses measured with the APE system in 2009 are presented. This method is efficient, accurate, and cost-effective.

  16. On calibrating the sensor errors of a PDR-based indoor localization system.

    Science.gov (United States)

    Lan, Kun-Chan; Shih, Wen-Yuah

    2013-04-10

    Many studies utilize the signal strength of short-range radio systems (such as WiFi, ultrasound and infrared) to build a radio map for indoor localization, by deploying a large number of beacon nodes within a building. The drawback of such an infrastructure-based approach is that the deployment and calibration of the system are costly and labor-intensive. Some prior studies proposed the use of Pedestrian Dead Reckoning (PDR) for indoor localization, which does not require the deployment of beacon nodes. In a PDR system, a small number of sensors are put on the pedestrian. These sensors (such as a G-sensor and gyroscope) are used to estimate the distance and direction that a user travels. The effectiveness of a PDR system lies in its success in accurately estimating the user's moving distance and direction. In this work, we propose a novel waist-mounted based PDR that can measure the user's step lengths with a high accuracy. We utilize vertical acceleration of the body to calculate the user's change in height during walking. Based on the Pythagorean Theorem, we can then estimate each step length using this data. Furthermore, we design a map matching algorithm to calibrate the direction errors from the gyro using building floor plans. The results of our experiment show that we can achieve about 98.26% accuracy in estimating the user's walking distance, with an overall location error of about 0.48 m.

  17. Novel quantitative calibration approach for multi-configuration electromagnetic induction (EMI) systems using data acquired at multiple elevations

    Science.gov (United States)

    Tan, Xihe; Mester, Achim; von Hebel, Christian; van der Kruk, Jan; Zimmermann, Egon; Vereecken, Harry; van Waasen, Stefan

    2017-04-01

    Electromagnetic induction (EMI) systems offer a great potential to obtain highly resolved layered electrical conductivity models of the shallow subsurface. State-of-the-art inversion procedures require quantitative calibration of EMI data, especially for short-offset EMI systems where significant data shifts are often observed. These shifts are caused by external influences such as the presence of the operator, zero-leveling procedures, the field setup used to move the EMI system and/or cables close by. Calibrations can be performed by using collocated electrical resistivity measurements or taking soil samples, however, these two methods take a lot of time in the field. To improve the calibration in a fast and concise way, we introduce a novel on-site calibration method using a series of apparent electrical conductivity (ECa) values acquired at multiple elevations for a multi-configuration EMI system. No additional instrument or pre-knowledge of the subsurface is needed to acquire quantitative ECa data. By using this calibration method, we correct each coil configuration, i.e., transmitter and receiver coil separation and the horizontal or vertical coplanar (HCP or VCP) coil orientation with a unique set of calibration parameters. A multi-layer soil structure at the corresponding measurement location is inverted together with the calibration parameters using full-solution Maxwell equations for the forward modelling within the shuffled complex evolution (SCE) algorithm to find the optimum solution under a user-defined parameter space. Synthetic data verified the feasibility for calibrating HCP and VCP measurements of a custom made six-coil EMI system with coil offsets between 0.35 m and 1.8 m for quantitative data inversions. As a next step, we applied the calibration approach on acquired experimental data from a bare soil test field (Selhausen, Germany) for the considered EMI system. The obtained calibration parameters were applied to measurements over a 30 m

  18. Mathematical Modeling of Electrolyte Flow Dynamic Patterns and Volumetric Flow Penetrations in the Flow Channel over Porous Electrode Layered System in Vanadium Flow Battery with Serpentine Flow Field Design

    OpenAIRE

    Ke, Xinyou; Prahl, Joseph M.; Alexander, J. Iwan D.; Savinell, Robert F.

    2016-01-01

    In this work, a two-dimensional mathematical model is developed to study the flow patterns and volumetric flow penetrations in the flow channel over the porous electrode layered system in vanadium flow battery with serpentine flow field design. The flow distributions at the interface between the flow channel and porous electrode are examined. It is found that the non-linear pressure distributions can distinguish the interface flow distributions under the ideal plug flow and ideal parabolic fl...

  19. Designing remote web-based mechanical-volumetric flow meter ...

    African Journals Online (AJOL)

    ... remote web-based mechanical-volumetric flow meter reading systems based on ... damage and also provides the ability to control and manage consumption. ... existing infrastructure of the telecommunications is used in data transmission.

  20. LED based powerful nanosecond light sources for calibration systems of deep underwater neutrino telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Lubsandorzhiev, B.K. [Institute for Nuclear Research of the Russian Academy of Sciences (Russian Federation); Kepler Center for Astro and Particle Physics, University of Tuebingen (Germany)], E-mail: lubsand@pcbai10.inr.ruhep.ru; Poleshuk, R.V.; Shaibonov, B.A.J.; Vyatchin, Y.E. [Institute for Nuclear Research of the Russian Academy of Sciences (Russian Federation)

    2009-04-11

    Powerful nanosecond light sources based on LEDs have been developed for use in calibration systems of deep underwater neutrino telescopes. The light sources use either matrixes of ultra bright blue InGaN LEDs or new generation high power blue LEDs. It is shown that such light sources have light yield of up to 10{sup 10}-10{sup 12} photons per pulse with very fast light emission kinetics. The developed light sources are currently used in a number of astroparticle physics experiments, namely: the lake Baikal neutrino experiment, the TUNKA EAS experiment, etc.

  1. Cinematica: a system for calibrated, Macintosh-driven displays from within Mathematica.

    Science.gov (United States)

    Solomon, J A; Watson, A B

    1996-01-01

    Cinematica is a minimal system for producing calibrated grayscale movies on an Apple Macintosh computer from within the Mathematica programming environment. It makes use of the ISR Video Attenuator and the Video Toolbox software library developed by Denis Pelli. By design, Cinematica provides a very low-level interface to the display routine. Display instructions take the form of a list of pairs (image index, colormap index). The philosophy is that programming is much easier in Mathematica than in C, so we reserve the complexity for Mathematica. A few simple examples are provided.

  2. Gradient nonlinearity calibration and correction for a compact, asymmetric magnetic resonance imaging gradient system

    Science.gov (United States)

    Tao, S.; Trzasko, J. D.; Gunter, J. L.; Weavers, P. T.; Shu, Y.; Huston, J., III; Lee, S. K.; Tan, E. T.; Bernstein, M. A.

    2017-01-01

    Due to engineering limitations, the spatial encoding gradient fields in conventional magnetic resonance imaging cannot be perfectly linear and always contain higher-order, nonlinear components. If ignored during image reconstruction, gradient nonlinearity (GNL) manifests as image geometric distortion. Given an estimate of the GNL field, this distortion can be corrected to a degree proportional to the accuracy of the field estimate. The GNL of a gradient system is typically characterized using a spherical harmonic polynomial model with model coefficients obtained from electromagnetic simulation. Conventional whole-body gradient systems are symmetric in design; typically, only odd-order terms up to the 5th-order are required for GNL modeling. Recently, a high-performance, asymmetric gradient system was developed, which exhibits more complex GNL that requires higher-order terms including both odd- and even-orders for accurate modeling. This work characterizes the GNL of this system using an iterative calibration method and a fiducial phantom used in ADNI (Alzheimer’s Disease Neuroimaging Initiative). The phantom was scanned at different locations inside the 26 cm diameter-spherical-volume of this gradient, and the positions of fiducials in the phantom were estimated. An iterative calibration procedure was utilized to identify the model coefficients that minimize the mean-squared-error between the true fiducial positions and the positions estimated from images corrected using these coefficients. To examine the effect of higher-order and even-order terms, this calibration was performed using spherical harmonic polynomial of different orders up to the 10th-order including even- and odd-order terms, or odd-order only. The results showed that the model coefficients of this gradient can be successfully estimated. The residual root-mean-squared-error after correction using up to the 10th-order coefficients was reduced to 0.36 mm, yielding spatial accuracy comparable to

  3. The calibration system of the new g-2 experiment at Fermilab

    Science.gov (United States)

    Anastasi, A.; Babusci, D.; Cantatore, G.; Cauz, D.; Corradi, G.; Dabagov, S.; Di Meo, P.; Di Sciascio, G.; Di Stefano, R.; Ferrari, C.; Fienberg, A. T.; Fioretti, A.; Gabbanini, C.; Hampai, D.; Hertzog, D. W.; Iacovacci, M.; Karuza, M.; Kaspar, J.; Marignetti, F.; Mastroianni, S.; Moricciani, D.; Pauletta, G.; Santi, L.; Venanzoni, G.

    2016-07-01

    The muon anomaly (g - 2) μ / 2 has been measured to 0.54 parts per million by E821 experiment at Brookhaven National Laboratory, and at present there is a 3-4 standard-deviation difference between the Standard Model prediction and the experimental value. A new muon g-2 experiment, E989, is being prepared at Fermilab that will improve the experimental error by a factor of four to clarify this difference. A central component to reach this fourfold improvement in accuracy is the high-precision laser calibration system which should monitor the gain fluctuations of the calorimeter photodetectors at 0.04% accuracy.

  4. Evaluation of the sensitivity of two 3D diode array dosimetry systems to setup error for quality assurance (QA) of volumetric-modulated arc therapy (VMAT).

    Science.gov (United States)

    Li, Guangjun; Bai, Sen; Chen, Nianyong; Henderson, Lansdale; Wu, Kui; Xiao, Jianghong; Zhang, Yingjie; Jiang, Qingfeng; Jiang, Xiaoqin

    2013-09-06

    The purpose of this study is to evaluate the sensitivities of 3D diode arrays to setup error for patient-specific quality assurance (QA) of volumetric-modulated arc therapy (VMAT). Translational setup errors of ± 1, ± 2, and ± 3 mm in the RL, SI, and AP directions and rotational setup errors of ± 1° and ± 2° in the pitch, roll, and yaw directions were set up in two phantom systems, ArcCHECK and Delta4, with VMAT plans for 11 patients. Cone-beam computed tomography (CBCT) followed by automatic correction using a HexaPOD 6D treatment couch ensured the position accuracy. Dose distributions of the two phantoms were compared in order to evaluate the agreement between calculated and measured values by using γ analysis with 3%/3 mm, 3%/2 mm, and 2%/2 mm criteria. To determine the impact on setup error for VMAT QA, we evaluated the sensitivity of results acquired by both 3D diode array systems to setup errors in translation and rotation. For the VMAT QA of all patients, the pass rate with the 3%/3 mm criteria exceeded 95% using either phantom. For setup errors of 3 mm and 2°, respectively, the pass rates with the 3%/3mm criteria decreased by a maximum of 14.0% and 23.5% using ArcCHECK, and 14.4% and 5.0% using Delta4. Both systems are sensitive to setup error, and do not have mechanisms to account for setup errors in the software. The sensitivity of both VMAT QA systems was strongly dependent on the patient-specific plan. The sensitivity of ArcCHECK to the rotational error was higher than that of Delta4. In order to achieve less than 3% mean pass rate reduction of VMAT plan QA with the 3%/3 mm criteria, a setup accuracy of 2 mm/1° and 2 mm/2° is required for ArcCheck and Delta4 devices, respectively. The cumulative effect of the combined 2 mm translational and 1° rotational errors caused 3.8% and 2.4% mean pass rates reduction with 3%/3 mm criteria, respectively, for ArcCHECK and Delta4 systems. For QA of VMAT plans for nasopharyngeal cancer (NPC) using the Arc

  5. High-accuracy calibration of an adaptive optics system using a phase shifting diffraction interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Bauman, B J; Campbell, E W; Olivier, S S; Sweider, D R

    1999-06-23

    A phase-shifting diffraction interferometer (PSDI) has been integrated into an adaptive optics (AO) system developed by LLNL for use on the three meter Shane telescope at Lick Observatory. The interferometer is an all fiber optic design, which is extremely compact. It is useful for calibrating the control sensors, measuring the aberrations of the entire AO optical train, and measuring the influence functions of the individual actuators on the deformable mirror. The PSDI is particularly well suited for this application because it measures converging, quasi-spherical wavefronts, such as are produced by an AO imaging system. Thus, a PSDI can be used to measure the aberrations of the entire AO system, in-situ and without errors introduced by auxiliary optics. This provides an extremely accurate measurement ({approximately} 5 nm RMS) of the optical properties of the AO system.

  6. Calibration of line structured light vision system based on camera's projective center

    Institute of Scientific and Technical Information of China (English)

    ZHU Ji-gui; LI Yan-jun; YE Sheng-hua

    2005-01-01

    Based on the characteristics of line structured light sensor, a speedy method for the calibration was established. With the coplanar reference target, the spacial pose between camera and optical plane can be calibrated by using of the camera's projective center and the light's information in the camera's image surface. Without striction to the movement of the coplanar reference target and assistant adjustment equipment, this calibration method can be implemented. This method has been used and decreased the cost of calibration equipment, simplified the calibration procedure, improved calibration efficiency. Using experiment, the sensor can attain relative accuracy about 0.5%, which indicates the rationality and effectivity of this method.

  7. The Research of Through-casing Resistivity Logging Logging Calibration System Leakage Current Measurement Method

    Directory of Open Access Journals (Sweden)

    ZHANG Jiatian

    2013-07-01

    Full Text Available This paper introduces the logging principle of through-casing resistivity logging technology, finds a phenomenon that the leakage current measurements are susceptible to sufferring interferences. The through-casing resistivity logging technology in Russia and that of Schlumberger are studied, and the system of through-casing resistivity logging is established to improve the accuracy of calibrating, testing and measuring of the instrument. In this paper, distribution parameters of the form is replaced by the lumped parameter, and precision resistor array simulation in formation leakage current and scale pool simulation in different resistivity of formation are conducted, which make the dynamic range of the simulation in formation resistivity of the medium increase to 1- 300 Ω·m and meet the requirement of through-casing resistivity logging technology measurement range, 1 Ω·m ~ 100 Ω·m. Since the measuring signals of calibration acquisition and processing systems are extremely weak and calculation signals need to tell the nV (nanovolts level, the high accurate data acquisition system of 24 digits is applied.

  8. Development of a Calibration System for Cryogenic Light Detectors in CUPID

    Science.gov (United States)

    Luo, Meng; Kolomensky, Yury; O'Donnell, Thomas; Schmidt, Benjamin; Cupid Collaboration

    2017-01-01

    If neutrino is a Majorana particle, it is possible to observe neutrinoless double beta decay (0 νββ), whose signature is a monochromatic line at the Q-value of the decay in the energy spectrum of the two electrons. Cryogenic Underground Observatory for Rare Events (CUORE) is an experiment which aims to search for 0 νββ in 130Te with TeO2 bolometers, whose background is dominated by α particles from natural radioactivity in the detector material. CUPID (CUORE Upgrade with Particle IDentification) is the next generation experiment proposed to distinguish 0 νββ events from those of α particles with Cherenkov radiation. An important part of CUPID R&D is to design, build and characterize a calibration system that can generate a known amount of light and transport that light to the dilution refrigerator at mK temperatures. We describe the design, implementation and performance of a calibration system developed for bolometric light detectors. Preparation work includes researching and selecting a light source (LED). A transport system (optical fiber) was developed to direct the light to the coldest part of the dilution refrigerator. Additionally, the light yield attenuation of optical fiber at cryogenic temperatures was measured. This project is supported by National Science Foundation and UC-Berkeley.

  9. On the Free Vibration Modeling of Spindle Systems: A Calibrated Dynamic Stiffness Matrix

    Directory of Open Access Journals (Sweden)

    Omar Gaber

    2014-01-01

    Full Text Available The effect of bearings on the vibrational behavior of machine tool spindles is investigated. This is done through the development of a calibrated dynamic stiffness matrix (CDSM method, where the bearings flexibility is represented by massless linear spring elements with tuneable stiffness. A dedicated MATLAB code is written to develop and to assemble the element stiffness matrices for the system’s multiple components and to apply the boundary conditions. The developed method is applied to an illustrative example of spindle system. When the spindle bearings are modeled as simply supported boundary conditions, the DSM model results in a fundamental frequency much higher than the system’s nominal value. The simply supported boundary conditions are then replaced by linear spring elements, and the spring constants are adjusted such that the resulting calibrated CDSM model leads to the nominal fundamental frequency of the spindle system. The spindle frequency results are also validated against the experimental data. The proposed method can be effectively applied to predict the vibration characteristics of spindle systems supported by bearings.

  10. Design, calibration, and operation of 220Rn stack effluent monitoring systems at Argonne National Laboratory.

    Science.gov (United States)

    Munyon, W J; Kretz, N D; Marchetti, F P

    1994-09-01

    A group of stack effluent monitoring systems have been developed to monitor discharges of 220Rn from a hot cell facility at Argonne National Laboratory. The stack monitors use flow-through scintillation cells and are completely microprocessor-based systems. A method for calibrating the stack monitors in the laboratory and in the field is described. A nominal calibration factor for the stack monitoring systems in use is 15.0 cts min-1 per kBq m-3 (0.56 cts min-1 per pCi L-1) +/- 26% at the 95% confidence level. The plate-out fraction of decay products in the stack monitor scintillation cells, without any pre-filtering, was found to be nominally 25% under normal operating conditions. When the sample was pre-filtered upstream of the scintillation cell, the observed cell plate-out fraction ranged from 16-22%, depending on the specific sampling conditions. The instantaneous 220Rn stack concentration can be underestimated or overestimated when the steady state condition established between 220Rn and its decay products in the scintillation cell is disrupted by sudden changes in the monitored 220Rn concentration. For long-term measurements, however, the time-averaged response of the monitor represents the steady state condition and leads to a reasonable estimate of the average 220Rn concentration during the monitoring period.

  11. Delivery Parameter Variations and Early Clinical Outcomes of Volumetric Modulated Arc Therapy for 31 Prostate Cancer Patients: An Intercomparison of Three Treatment Planning Systems

    Directory of Open Access Journals (Sweden)

    Shinichi Tsutsumi

    2013-01-01

    Full Text Available We created volumetric modulated arc therapy (VMAT plans for 31 prostate cancer patients using one of three treatment planning systems (TPSs—ERGO++, Monaco, or Pinnacle—and then treated those patients. A dose of 74 Gy was prescribed to the planning target volume (PTV. The rectum, bladder, and femur were chosen as organs at risk (OARs with specified dose-volume constraints. Dose volume histograms (DVHs, the mean dose rate, the beam-on time, and early treatment outcomes were evaluated and compared. The DVHs calculated for the three TPSs were comparable. The mean dose rates and beam-on times for Ergo++, Monaco, and SmartArc were, respectively, 174.3 ± 17.7, 149.7 ± 8.4, and 185.8 ± 15.6 MU/min and 132.7 ± 8.4, 217.6 ± 13.1, and 127.5 ± 27.1 sec. During a follow-up period of 486.2 ± 289.9 days, local recurrence was not observed, but distant metastasis was observed in a single patient. Adverse events of grade 3 to grade 4 were not observed. The mean dose rate for Monaco was significantly lower than that for ERGO++ and SmartArc (P<0.0001, and the beam-on time for Monaco was significantly longer than that for ERGO++ and SmartArc (P<0.0001. Each TPS was successfully used for prostate VMAT planning without significant differences in early clinical outcomes despite significant TPS-specific delivery parameter variations.

  12. Volumetric water control in a large-scale open canal irrigation system with many smallholders: The case of Chancay-Lambayeque in Peru

    NARCIS (Netherlands)

    Vos, J.M.C.; Vincent, L.F.

    2011-01-01

    Volumetric water control (VWC) is widely seen as a means to increase productivity through flexible scheduling and user incentives to apply just enough water. However, the technical and social requirements for VWC are poorly understood. Also, many experts assert that VWC in large-scale open canals

  13. Breast density mapping based upon system calibration, x-ray techniques, and FFDM images

    Science.gov (United States)

    Chen, Biao; Smith, Andrew P.; Jing, Zhenxue; Wu, Tao

    2007-03-01

    Clinical studies have correlated a high breast density to a women's risk of breast cancer. A breast density measurement that can quantitatively depict the volume distribution and percentage of dense tissues in breasts would be very useful for risk factor assessment of breast cancer, and might be more predictive of risks than the common but subjective and coarse 4-point BIRADS scale. This paper proposes to use a neural-network mapping to compute the breast density information based upon system calibration data, x-ray techniques, and Full Field Digital Mammography (FFDM) images. The mapping consists of four modules, namely, system calibration, generator of beam quality, generator of normalized absorption, and a multi-layer feed-forward neural network. As the core of breast density mapping, the network accepts x-ray target/filter combination, normalized x-ray absorption, pixel-wise breast thickness map, and x-ray beam quality during image acquisition as input elements, and exports a pixel-wise breast density distribution and a single breast density percentage for the imaged breast. Training and testing data sets for the design and verification of the network were formulated from calibrated x-ray beam quality, imaging data with a step wedge phantom under a variety x-ray imaging techniques, and nominal breast densities of tissue equivalent materials. The network was trained using a Levenberg-Marquardt algorithm based back-propagation learning method. Various thickness and glandular density phantom studies were performed with clinical x-ray techniques. Preliminary results showed that the neural network mapping is promising in accurately computing glandular density distribution and breast density percentage.

  14. An investigation of automatic exposure control calibration for chest imaging with a computed radiography system.

    Science.gov (United States)

    Moore, C S; Wood, T J; Avery, G; Balcam, S; Needler, L; Beavis, A W; Saunderson, J R

    2014-05-07

    The purpose of this study was to examine the use of three physical image quality metrics in the calibration of an automatic exposure control (AEC) device for chest radiography with a computed radiography (CR) imaging system. The metrics assessed were signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm), all measured using a uniform chest phantom. Subsequent calibration curves were derived to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated chest images with correct detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated chest images contained clinically realistic projected anatomy and anatomical noise and were scored by experienced image evaluators. Constant DDI and CNR curves do not appear to provide optimized performance across the diagnostic energy range. Conversely, constant eNEQm and SNR do appear to provide optimized performance, with the latter being the preferred calibration metric given as it is easier to measure in practice. Medical physicists may use the SNR image quality metric described here when setting up and optimizing AEC devices for chest radiography CR systems with a degree of confidence that resulting clinical image quality will be adequate for the required clinical task. However, this must be done with close cooperation of expert image evaluators, to ensure appropriate levels of detector air kerma.

  15. Quantitative fluorescence and elastic scattering tissue polarimetry using an Eigenvalue calibrated spectroscopic Mueller matrix system.

    Science.gov (United States)

    Soni, Jalpa; Purwar, Harsh; Lakhotia, Harshit; Chandel, Shubham; Banerjee, Chitram; Kumar, Uday; Ghosh, Nirmalya

    2013-07-01

    A novel spectroscopic Mueller matrix system has been developed and explored for both fluorescence and elastic scattering polarimetric measurements from biological tissues. The 4 × 4 Mueller matrix measurement strategy is based on sixteen spectrally resolved (λ = 400 - 800 nm) measurements performed by sequentially generating and analyzing four elliptical polarization states. Eigenvalue calibration of the system ensured high accuracy of Mueller matrix measurement over a broad wavelength range, either for forward or backscattering geometry. The system was explored for quantitative fluorescence and elastic scattering spectroscopic polarimetric studies on normal and precancerous tissue sections from human uterine cervix. The fluorescence spectroscopic Mueller matrices yielded an interesting diattenuation parameter, exhibiting differences between normal and precancerous tissues.

  16. The research on calibration methods of dual-CCD laser three-dimensional human face scanning system

    Science.gov (United States)

    Wang, Jinjiang; Chang, Tianyu; Ge, Baozhen; Tian, Qingguo; Yang, Fengting; Shi, Shendong

    2013-09-01

    In this paper, on the basis of considering the performance advantages of two-step method, we combines the stereo matching of binocular stereo vision with active laser scanning to calibrate the system. Above all, we select a reference camera coordinate system as the world coordinate system and unity the coordinates of two CCD cameras. And then obtain the new perspective projection matrix (PPM) of each camera after the epipolar rectification. By those, the corresponding epipolar equation of two cameras can be defined. So by utilizing the trigonometric parallax method, we can measure the space point position after distortion correction and achieve stereo matching calibration between two image points. Experiments verify that this method can improve accuracy and system stability is guaranteed. The stereo matching calibration has a simple process with low-cost, and simplifies regular maintenance work. It can acquire 3D coordinates only by planar checkerboard calibration without the need of designing specific standard target or using electronic theodolite. It is found that during the experiment two-step calibration error and lens distortion lead to the stratification of point cloud data. The proposed calibration method which combining active line laser scanning and binocular stereo vision has the both advantages of them. It has more flexible applicability. Theory analysis and experiment shows the method is reasonable.

  17. All Photons Imaging Through Volumetric Scattering

    Science.gov (United States)

    Satat, Guy; Heshmat, Barmak; Raviv, Dan; Raskar, Ramesh

    2016-01-01

    Imaging through thick highly scattering media (sample thickness ≫ mean free path) can realize broad applications in biomedical and industrial imaging as well as remote sensing. Here we propose a computational “All Photons Imaging” (API) framework that utilizes time-resolved measurement for imaging through thick volumetric scattering by using both early arrived (non-scattered) and diffused photons. As opposed to other methods which aim to lock on specific photons (coherent, ballistic, acoustically modulated, etc.), this framework aims to use all of the optical signal. Compared to conventional early photon measurements for imaging through a 15 mm tissue phantom, our method shows a two fold improvement in spatial resolution (4db increase in Peak SNR). This all optical, calibration-free framework enables widefield imaging through thick turbid media, and opens new avenues in non-invasive testing, analysis, and diagnosis. PMID:27683065

  18. Rapid mapping of volumetric machine errors using distance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Krulewich, D.A.

    1998-04-01

    This paper describes a relatively inexpensive, fast, and easy to execute approach to maping the volumetric errors of a machine tool, coordinate measuring machine, or robot. An error map is used to characterize a machine or to improve its accuracy by compensating for the systematic errors. The method consists of three steps: (1) models the relationship between volumetric error and the current state of the machine, (2) acquiring error data based on distance measurements throughout the work volume; and (3)fitting the error model using the nonlinear equation for the distance. The error model is formulated from the kinematic relationship among the six degrees of freedom of error an each moving axis. Expressing each parametric error as function of position each is combined to predict the error between the functional point and workpiece, also as a function of position. A series of distances between several fixed base locations and various functional points in the work volume is measured using a Laser Ball Bar (LBB). Each measured distance is a non-linear function dependent on the commanded location of the machine, the machine error, and the location of the base locations. Using the error model, the non-linear equation is solved producing a fit for the error model Also note that, given approximate distances between each pair of base locations, the exact base locations in the machine coordinate system determined during the non-linear filling procedure. Furthermore, with the use of 2048 more than three base locations, bias error in the measuring instrument can be removed The volumetric errors of three-axis commercial machining center have been mapped using this procedure. In this study, only errors associated with the nominal position of the machine were considered Other errors such as thermally induced and load induced errors were not considered although the mathematical model has the ability to account for these errors. Due to the proprietary nature of the projects we are

  19. Automatic Calibration Method of Voxel Size for Cone-beam 3D-CT Scanning System

    CERN Document Server

    Yang, Min; Liu, Yipeng; Men, Fanyong; Li, Xingdong; Liu, Wenli; Wei, Dongbo

    2013-01-01

    For cone-beam three-dimensional computed tomography (3D-CT) scanning system, voxel size is an important indicator to guarantee the accuracy of data analysis and feature measurement based on 3D-CT images. Meanwhile, the voxel size changes with the movement of the rotary table along X-ray direction. In order to realize the automatic calibration of the voxel size, a new easily-implemented method is proposed. According to this method, several projections of a spherical phantom are captured at different imaging positions and the corresponding voxel size values are calculated by non-linear least square fitting. Through these interpolation values, a linear equation is obtained, which reflects the relationship between the rotary table displacement distance from its nominal zero position and the voxel size. Finally, the linear equation is imported into the calibration module of the 3D-CT scanning system, and when the rotary table is moving along X-ray direction, the accurate value of the voxel size is dynamically expo...

  20. On data requirements for calibration of integrated models for urban water systems.

    Science.gov (United States)

    Langeveld, Jeroen; Nopens, Ingmar; Schilperoort, Remy; Benedetti, Lorenzo; de Klein, Jeroen; Amerlinck, Youri; Weijers, Stefan

    2013-01-01

    Modeling of integrated urban water systems (IUWS) has seen a rapid development in recent years. Models and software are available that describe the process dynamics in sewers, wastewater treatment plants (WWTPs), receiving water systems as well as at the interfaces between the submodels. Successful applications of integrated modeling are, however, relatively scarce. One of the reasons for this is the lack of high-quality monitoring data with the required spatial and temporal resolution and accuracy to calibrate and validate the integrated models, even though the state of the art of monitoring itself is no longer the limiting factor. This paper discusses the efforts to be able to meet the data requirements associated with integrated modeling and describes the methods applied to validate the monitoring data and to use submodels as software sensor to provide the necessary input for other submodels. The main conclusion of the paper is that state of the art monitoring is in principle sufficient to provide the data necessary to calibrate integrated models, but practical limitations resulting in incomplete data-sets hamper widespread application. In order to overcome these difficulties, redundancy of future monitoring networks should be increased and, at the same time, data handling (including data validation, mining and assimilation) should receive much more attention.

  1. Automatic Calibration of Frequency Compensation System in Computer-Controlled Patch-Clamp Amplifier

    Directory of Open Access Journals (Sweden)

    Jun Xion

    2007-01-01

    Full Text Available Computer-controlled patch-clamp amplifier is a digitally controlled analog device used to record the cellular ion channel currents in electrophysiology research. The inherent bandwidth and performance of the headstage is limited by the stray capacitance and distributed capacitance across the feedback resistors. In order to effectively improve the performance of the headstage, the paper advanced a simplified automatic calibration method of frequency compensation system in resistor-feedback patch-clamp amplifier. The dynamic model of headstage was approximate as a two poles and one zero system in the transfer function by experience and test results, so the dynamic characteristics of the headstage were obtained employing least squares parameter estimation algorithm. Further more, the compensation parameter of high frequency booster can be estimated by the time constant of main pole of headstage. And automatic adjustment of the parameters in transient response correction stage was performed as a least squares fitting problem. The software routine running on the host computer conducted all operations of frequency compensation. Experimental results demonstrate that the simplified automatic calibration method can substantially extend the bandwidth and minimize step response error of headstage.

  2. Time Calibration of the ATLAS Hadronic Tile Calorimeter using the Laser System

    CERN Document Server

    Clément, C; Solovyanov, O; Vivarelli, I

    2008-01-01

    The ATLAS Tile Calorimeter (TileCal) will be used to measure i) the energy of hadronic showers and ii) the Time of Flight (ToF) of particles passing through it. To allow for optimal reconstruction of the energy deposited in the calorimeter with optimal filtering, the phase between the signal sampling clock and the maximum of the incoming pulses needs to be minimised and the residual difference needs to be measured for later use for both energy and time of flight measurements. In this note we present the timing equalisation of all TileCal read out channels using the TileCal laser calibration system and a measurement of the time differences between the 4 TileCal TTC partitions. The residual phases after timing equalisation have been measured. Several characteristics of the laser calibration system relevant for timing have also been studied and a solution is proposed to take into account the time difference between the high and low gain paths. Finally we discuss the sources of uncertainties on the timing of the ...

  3. Calibration of the videospectral system for the space experiment "Uragan" onboard the ISS

    Science.gov (United States)

    Krot, Yury; Katkovsky, Leonid; Beliaev, Boris; Martenov, Anton

    2015-10-01

    The videospectral system (VSS) intended for ecological space experiment on board of the International Space Station (ISS) has been developed by the Aerospace Researches Department of the Institute of Applied Physical Problems of the Belarusian State University. The VSS is intended for registration of color images and spectra of underlying surface. The system comprises an imaging channel and three CCD-array spectrometers based on diffraction gratings. A CCD-array photodetector of each spectrometer measures the spectral radiation distribution in rows, and the spatial distribution in columns. Astigmatism is a typical aberration of polychromators based on concave spherical gratings - rays in tangential and sagittal planes are focused at different points. This degrades the spectral or spatial resolution along the entrance slit. The proposed method of obtaining high spatial resolution without spectral resolution loss consists in a displacement of the output end of the imaging fiber along the optical axis at a specified distance from the entrance slit. The entrance slit operates as a one-dimensional aperture to obtain high spectral resolution. The image and spectral channel of the VSS were calibrated by wavelengths and spectral sensitivity. A method of the second diffraction order correction has been proposed for spectrometers based on diffraction gratings. Some results of laboratory calibration and the first application are presented.

  4. Diamagnetic Levitation Cantilever System for the Calibration of Normal Force Atomic Force Microscopy Measurements

    Science.gov (United States)

    Torres, Jahn; Yi, Jin-Woo; Murphy, Colin; Kim, Kyung-Suk

    2011-03-01

    In this presentation we report a novel technique for normal force calibration for Atomic Force Microcopy (AFM) adhesion measurements known as the diamagnetic normal force calibration (D-NFC) system. The levitation produced by the repulsion between a diamagnetic graphite sheet and a set of rare-earth magnets is used in order to produce an oscillation due to an unstable mechanical moment produced by a silicon cantilever supported on the graphite. The measurement of the natural frequency of this oscillation allows for the calculation of the stiffness of the system to three-digit accuracy. The D-NFC response was proven to have a high sensitivity for the structure of water molecules collected on its surface. This in turns allows for the study of the effects of coatings on the structure of surface water. This work was supported by the Coatings/Biofouling Program and the Maritime Sensing Program of the Office of Naval Research as well as the ILIR Program of the Naval Undersea Warfare Center DIVNPT.

  5. Development and Calibration of a System-Integrated Rotorcraft Finite Element Model for Impact Scenarios

    Science.gov (United States)

    Annett, Martin S.; Horta, Lucas G.; Jackson, Karen E.; Polanco, Michael A.; Littell, Justin D.

    2012-01-01

    Two full-scale crash tests of an MD-500 helicopter were conducted in 2009 and 2010 at NASA Langley's Landing and Impact Research Facility in support of NASA s Subsonic Rotary Wing Crashworthiness Project. The first crash test was conducted to evaluate the performance of an externally mounted composite deployable energy absorber (DEA) under combined impact conditions. In the second crash test, the energy absorber was removed to establish baseline loads that are regarded as severe but survivable. The presence of this energy absorbing device reduced the peak impact acceleration levels by a factor of three. Accelerations and kinematic data collected from the crash tests were compared to a system-integrated finite element model of the test article developed in parallel with the test program. In preparation for the full-scale crash test, a series of sub-scale and MD-500 mass simulator tests were conducted to evaluate the impact performances of various components and subsystems, including new crush tubes and the DEA blocks. Parameters defined for the system-integrated finite element model were determined from these tests. Results from 19 accelerometers placed throughout the airframe were compared to finite element model responses. The model developed for the purposes of predicting acceleration responses from the first crash test was inadequate when evaluating more severe conditions seen in the second crash test. A newly developed model calibration approach that includes uncertainty estimation, parameter sensitivity, impact shape orthogonality, and numerical optimization was used to calibrate model results for the full-scale crash test without the DEA. This combination of heuristic and quantitative methods identified modeling deficiencies, evaluated parameter importance, and proposed required model changes. The multidimensional calibration techniques presented here are particularly effective in identifying model adequacy. Acceleration results for the calibrated model were

  6. The Monitoring and Calibration Web Systems for the ATLAS Tile Calorimeter Data Quality Analysis

    CERN Document Server

    Sivolella, A; The ATLAS collaboration; Ferreira, F

    2012-01-01

    The Tile Calorimeter (TileCal), one of the ATLAS detectors, has four partitions, where each one contains 64 modules and each module has up to 48 PhotoMulTipliers (PMTs), totalizing more than 10,000 electronic channels. The Monitoring and Calibration Web System (MCWS) supports data quality analyses at channels level. This application was developed to assess the detector status and verify its performance, presenting the problematic known channels list from the official database that stores the detector conditions data (COOL). The bad channels list guides the data quality validator during analyses in order to identify new problematic channels. Through the system, it is also possible to update the channels list directly in the COOL database. MCWS generates results, as eta-phi plots and comparative tables with masked channels percentage, which concerns TileCal status, and it is accessible by all ATLAS collaboration. Annually, there is an intervention on LHC (Large Hadronic Collider) when the detector equipments (P...

  7. Methodology for the digital calibration of analog circuits and systems with case studies

    CERN Document Server

    Pastre, Marc

    2006-01-01

    Methodology for the Digital Calibration of Analog Circuits and Systems shows how to relax the extreme design constraints in analog circuits, allowing the realization of high-precision systems even with low-performance components. A complete methodology is proposed, and three applications are detailed. To start with, an in-depth analysis of existing compensation techniques for analog circuit imperfections is carried out. The M/2+M sub-binary digital-to-analog converter is thoroughly studied, and the use of this very low-area circuit in conjunction with a successive approximations algorithm for digital compensation is described. A complete methodology based on this compensation circuit and algorithm is then proposed. The detection and correction of analog circuit imperfections is studied, and a simulation tool allowing the transparent simulation of analog circuits with automatic compensation blocks is introduced. The first application shows how the sub-binary M/2+M structure can be employed as a conventional di...

  8. Geometry calibration between X-ray source and detector for tomosynthesis with a portable X-ray system.

    Science.gov (United States)

    Sato, Kohei; Ohnishi, Takashi; Sekine, Masashi; Haneishi, Hideaki

    2017-05-01

    Tomosynthesis is attracting attention as a low-dose tomography technology compared with X-ray CT. However, conventional tomosynthesis imaging devices are large and stationary. Furthermore, there is a limitation in the working range of the X-ray source during image acquisition. We have previously proposed the use of a portable X-ray device for tomosynthesis that can be used for ward rounds and emergency medicine. The weight of this device can be reduced by using a flat panel detector (FPD), and flexibility is realized by the free placement of the X-ray source and FPD. Tomosynthesis using a portable X-ray device requires calibration of the geometry between the X-ray source and detector at each image acquisition. We propose a method for geometry calibration and demonstrate tomosynthesis image reconstruction by this method. An image processing-based calibration method using an asymmetric and multilayered calibration object (AMCO) is presented. Since the AMCO is always attached to the X-ray source housing for geometry calibration, the additional setting of a calibration object or marker around or on the patients is not required. The AMCO's multilayer structure improves the calibration accuracy, especially in the out-of-plane direction. Two experiments were conducted. The first was performed to evaluate the calibration accuracy using an XY positioning stage and a gonio stage. As a result, an accuracy of approximately 1 mm was achieved both in the in-plane and out-of-plane directions. An angular accuracy of approximately [Formula: see text] was confirmed. The second experiment was conducted to evaluate the reconstructed image using a foot model phantom. Only the sagittal plane could be clearly observed with the proposed method. We proposed a tomosynthesis imaging system using a portable X-ray device. From the experimental results, the proposed method could provide sufficient calibration accuracy and a clear sagittal plane of the reconstructed tomosynthesis image.

  9. Calibration Standards for Surface Topography Measuring Systems down to Nanometric Range

    DEFF Research Database (Denmark)

    Trumpold, H.; De Chiffre, Leonardo; Andreasen, Jan Lasson

    calibrator has been designed, built and tested. Primary calibration standards have been produced by ion-beam and plasma etching (step height standards), by holographic generation of sinusoidal structures with two-beam interference exposure and by ultra-precision diamond cutting. From primary standards...... to be replicated during all stages of the replication processes. Procedures for cleaning glass, PVC, PC, PMM and Ni-surfaces have been developed and tested. Calibration procedures for calibration standards and for calibrating instruments in X-, Y- and Z-direction have been developed and tested. Proposals...

  10. Analysis of Gafchromic EBT3 film calibration irradiated with gamma rays from different systems: Gamma Knife and Cobalt-60 unit.

    Science.gov (United States)

    Najafi, Mohsen; Geraily, Ghazale; Shirazi, Alireza; Esfahani, Mahbod; Teimouri, Javad

    2017-01-01

    In recent years, Gafchromic films are used as an advanced instrument for dosimetry systems. The EBT3 films are a new generation of Gafchromic films. Our main interest is to compare the response of the EBT3 films exposed to gamma rays provided by the Theratron 780C as a conventional radiotherapy system and the Leksell Gamma Knife as a stereotactic radiotherapy system (SRS). Both systems use Cobalt-60 sources, thus using the same energy. However, other factors such as source-to-axis distance, number of sources, dose rate, direction of irradiation, shape of phantom, the field shape of radiation, and different scatter contribution may influence the calibration curve. Calibration curves for the 2 systems were measured and plotted for doses ranging from 0 to 40 Gy at the red and green channels. The best fitting curve was obtained with the Levenberg-Marquardt algorithm. Also, the component of dose uncertainty was obtained for any calibration curve. With the best fitting curve for the EBT3 films, we can use the calibration curve to measure the absolute dose in radiation therapy. Although there is a small deviation between the 2 curves, the p-value at any channel shows no significant difference between the 2 calibration curves. Therefore, the calibration curve for each system can be the same because of minor differences. The results show that with the best fitting curve from measured data, while considering the measurement uncertainties related to them, the EBT3 calibration curve can be used to measure the unknown dose both in SRS and in conventional radiotherapy. Copyright © 2017. Published by Elsevier Inc.

  11. 360度可环视全屏体三维显示系统%360° Viewable Volumetric 3D Display System with Full Screen

    Institute of Scientific and Technical Information of China (English)

    刘影; 潘文平; 张赵行; 刘永; 陈兴华

    2011-01-01

    研究了一种全屏体三维显示系统.以数字微镜器件(DMD)作为空间光调制器(SLM),将三维模型的螺旋切片序列投射到高速旋转的螺旋屏上,由于视觉暂留效应,切片序列便被人眼感知为360度可环视的三维立体图像.重点分析了基于全屏的成像空间的性能,研究了基于增强型体心立方(EBCC)采样算法的体素化策略.实验结果表明,增强型BCC采样算法较基于笛卡尔栅格的采样算法减少了30%的体素量,同时避免了体素模型出现空洞; 基于全屏的体三维空间超过原来半屏体三维显示系统的4倍,生成的图像亮度均匀;在400mm×300mm×250mm的长方体形成像空间内显示的立体图像,可从360°范围内任意视点裸眼观看.%Abstract: A volumetric display system with full helical screen is presented. When a series of helical slices of a 3D model is projected onto a rotating helical screen through a Digital Micro-mirror Device (DMD) as a fast Space Light Modulator (SLM), due to the persistence of vision, human observers are able to perceive a 360° viewable 3D image by fusing together the successive helical slices into a 3D image. We analyze the performance of the 3D imaging space created by a rotating helical screen, and emphasize the volexlization approach based on Enhanced Body-center Cubic (EBCC) sampling algorithm. Experimental results demonstrate that, compared with the voxelization approach based on Cartesian lattice, voxel hole avoidance and a voxel reduction of more than 30% are both achieved through utilizing EBCC sampling algorithm, and the prototype is capable of generating images with consistent brightness in a imaging space three times bigger than our former system with half screen. In the cuboid imaging space with length 400 mm, width 300 mm and height of 250 mm, 3D images can be viewed from any viewpoint without any special eyewear.

  12. On Calibrating the Sensor Errors of a PDR-Based Indoor Localization System

    Directory of Open Access Journals (Sweden)

    Wen-Yuah Shih

    2013-04-01

    Full Text Available Many studies utilize the signal strength of short-range radio systems (such as WiFi, ultrasound and infrared to build a radio map for indoor localization, by deploying a large number of beacon nodes within a building. The drawback of such an infrastructure-based approach is that the deployment and calibration of the system are costly and labor-intensive. Some prior studies proposed the use of Pedestrian Dead Reckoning (PDR for indoor localization, which does not require the deployment of beacon nodes. In a PDR system, a small number of sensors are put on the pedestrian. These sensors (such as a G-sensor and gyroscope are used to estimate the distance and direction that a user travels. The effectiveness of a PDR system lies in its success in accurately estimating the user’s moving distance and direction. In this work, we propose a novel waist-mounted based PDR that can measure the user’s step lengths with a high accuracy. We utilize vertical acceleration of the body to calculate the user’s change in height during walking. Based on the Pythagorean Theorem, we can then estimate each step length using this data. Furthermore, we design a map matching algorithm to calibrate the direction errors from the gyro using building floor plans. The results of our experiment show that we can achieve about 98.26% accuracy in estimating the user’s walking distance, with an overall location error of about 0.48 m.

  13. The Pointing System of the Herschel Space Observatory. Description, Calibration, Performance and Improvements

    CERN Document Server

    Sánchez-Portal, Miguel; Altieri, Bruno; Aussel, Hervé; Feuchtgruber, Helmut; Klaas, Ulrich; Linz, Hendrik; Lutz, Dieter; Merín, Bruno; Müller, Thomas; Nielbock, Markus; Oort, Marc; Pilbratt, Göran; Schmidt, Micha; Stephenson, Craig; Tuttlebee, Mark

    2014-01-01

    We present the activities carried out to calibrate and characterise the performance of the elements of attitude control and measurement on board the Herschel spacecraft. The main calibration parameters and the evolution of the indicators of the pointing performance are described, from the initial values derived from the observations carried out in the performance verification phase to those attained in the last year and half of mission, an absolute pointing error around or even below 1 arcsec, a spatial relative pointing error of some 1 arcsec and a pointing stability below 0.2 arsec. The actions carried out at the ground segment to improve the spacecraft pointing measurements are outlined. On-going and future developments towards a final refinement of the Herschel astrometry are also summarised. A brief description of the different components of the attitude control and measurement system (both in the space and in the ground segments) is also given for reference. We stress the importance of the cooperation b...

  14. The geometric calibration of cone-beam imaging and delivery systems in radiation therapy

    CERN Document Server

    Matsinos, E; Kaissl, Wolfgang; Matsinos, Evangelos

    2006-01-01

    We propose a method to achieve the geometric calibration of cone-beam imaging and delivery systems in radiation therapy; our approach applies to devices where an X-ray source and a flat-panel detector, facing each other, move in circular orbits around the irradiated object. In order to extract the parameters of the geometry from the data, we use a light needle phantom which is easy to manufacture. A model with ten free parameters (spatial lengths and distortion angles) has been put forth to describe the geometry and the mechanical imperfections of the units being calibrated; a few additional parameters are introduced to account for residual effects (small effects which lie beyond our model). The values of the model parameters are determined from one complete scan of the needle phantom via a robust optimisation scheme. The application of this method to two sets of five counterclockwise (ccw) and five clockwise (cw) scans yielded consistent and reproducible results. A number of differences have been observed be...

  15. An Overview of the Joint Polar Satellite System (JPSS Science Data Product Calibration and Validation

    Directory of Open Access Journals (Sweden)

    Lihang Zhou

    2016-02-01

    Full Text Available The Joint Polar Satellite System (JPSS will launch its first JPSS-1 satellite in early 2017. The JPSS-1 and follow-on satellites will carry aboard an array of instruments including the Visible Infrared Imaging Radiometer Suite (VIIRS, the Cross-track Infrared Sounder (CrIS, the Advanced Technology Microwave Sounder (ATMS, and the Ozone Mapping and Profiler Suite (OMPS. These instruments are similar to the instruments currently operating on the Suomi National Polar-orbiting Partnership (S-NPP satellite. In preparation for the JPSS-1 launch, the JPSS program at the Center for Satellite Applications and Research (JSTAR Calibration/Validation (Cal/Val teams, have laid out the Cal/Val plans to oversee JPSS-1 science products’ algorithm development efforts, verification and characterization of these algorithms during the pre-launch period, calibration and validation of the products during post-launch, and long-term science maintenance (LTSM. In addition, the team has developed the necessary schedules, deliverables and infrastructure for routing JPSS-1 science product algorithms for operational implementation. This paper presents an overview of these efforts. In addition, this paper will provide insight into the processes of both adapting S-NPP science products for JPSS-1 and performing upgrades for enterprise solutions, and will discuss Cal/Val processes and quality assurance procedures.

  16. The low-temperature energy calibration system for the CUORE bolometer array

    CERN Document Server

    Sangiorgio, S; Heeger, K M; Maruyama, R H; Nucciotti, A; Olcese, M; Wise, T S; Woodcraft, A L

    2009-01-01

    The CUORE experiment will search for neutrinoless double beta decay (0nDBD) of 130Te using an array of 988 TeO_2 bolometers operated at 10 mK in the Laboratori Nazionali del Gran Sasso (Italy). The detector is housed in a large cryogen-free cryostat cooled by pulse tubes and a high-power dilution refrigerator. The TeO_2 bolometers measure the event energies, and a precise and reliable energy calibration is critical for the successful identification of candidate 0nDBD and background events. The detector calibration system under development is based on the insertion of 12 gamma-sources that are able to move under their own weight through a set of guide tubes that route them from deployment boxes on the 300K flange down into position in the detector region inside the cryostat. The CUORE experiment poses stringent requirements on the maximum heat load on the cryostat, material radiopurity, contamination risk and the ability to fully retract the sources during normal data taking. Together with the integration into...

  17. Coordinates calibration in precision detection of 3D optical deformation measurement system

    Science.gov (United States)

    Lu, Honggang; Hu, Chunsheng; Wang, Xingshu; Gao, Yang; Wu, Wei

    2012-11-01

    In order to validate the detection precision of a three Dimensions Optical Deformation Measure System (3D-OMS), a calibration method of auxiliary coordinate and the optical coordinate base on theodolites has been proposed. The installation method by using theodolites to calibrate the auxiliary coordinate and the optical coordinate has been proposed. Specifically, after the auxiliary mirrors installed, the installation accuracy is detected, then we analyzed the influence of Axis-Error of theodolite under the practical condition of our experiment. Furthermore, the influence of validation precision for the 3D-OMS caused by the misalignment of auxiliary coordinate and optical coordinate is analyzed. According to our theoretical analysis and experiments results, the validation precision of the 3D-OMS can achieve an accuracy of 1″ at the conditions of the coordinate alignment accuracy is no more than 10' and the measuring range of 3D-OMS within +/-3'. Therefore, the proposed method can meet our high accuracy requirement while not sensitive to the installation error of auxiliary mirrors. This method is also available for other similar work.

  18. Surfactant enhanced volumetric sweep efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Harwell, J.H.; Scamehorn, J.F.

    1989-10-01

    Surfactant-enhanced waterflooding is a novel EOR method aimed to improve the volumetric sweep efficiencies in reservoirs. The technique depends upon the ability to induce phase changes in surfactant solutions by mixing with surfactants of opposite charge or with salts of appropriate type. One surfactant or salt solution is injected into the reservoir. It is followed later by injection of another surfactant or salt solution. The sequence of injections is arranged so that the two solutions do not mix until they are into the permeable regions well away from the well bore. When they mix at this point, by design they form a precipitate or gel-like coacervate phase, plugging this permeable region, forcing flow through less permeable regions of the reservoir, improving sweep efficiency. The selectivity of the plugging process is demonstrated by achieving permeability reductions in the high permeable regions of Berea sandstone cores. Strategies were set to obtain a better control over the plug placement and the stability of plugs. A numerical simulator has been developed to investigate the potential increases in oil production of model systems. Furthermore, the hardness tolerance of anionic surfactant solutions is shown to be enhanced by addition of monovalent electrolyte or nonionic surfactants. 34 refs., 32 figs., 8 tabs.

  19. A Novel Error Model of Optical Systems and an On-Orbit Calibration Method for Star Sensors

    Directory of Open Access Journals (Sweden)

    Shuang Wang

    2015-12-01

    Full Text Available In order to improve the on-orbit measurement accuracy of star sensors, the effects of image-plane rotary error, image-plane tilt error and distortions of optical systems resulting from the on-orbit thermal environment were studied in this paper. Since these issues will affect the precision of star image point positions, in this paper, a novel measurement error model based on the traditional error model is explored. Due to the orthonormal characteristics of image-plane rotary-tilt errors and the strong nonlinearity among these error parameters, it is difficult to calibrate all the parameters simultaneously. To solve this difficulty, for the new error model, a modified two-step calibration method based on the Extended Kalman Filter (EKF and Least Square Methods (LSM is presented. The former one is used to calibrate the main point drift, focal length error and distortions of optical systems while the latter estimates the image-plane rotary-tilt errors. With this calibration method, the precision of star image point position influenced by the above errors is greatly improved from 15.42% to 1.389%. Finally, the simulation results demonstrate that the presented measurement error model for star sensors has higher precision. Moreover, the proposed two-step method can effectively calibrate model error parameters, and the calibration precision of on-orbit star sensors is also improved obviously.

  20. SU-E-T-442: Geometric Calibration and Verification of a GammaPod Breast SBRT System

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C [Univ Maryland School of Medicine, Baltimore, MD (United States); Xcision Medical Systems, Columbia, MD (United States); Niu, Y; Maton, P; Hoban, P [Xcision Medical Systems, Columbia, MD (United States); Mutaf, Y [Univ Maryland School of Medicine, Baltimore, MD (United States)

    2015-06-15

    Purpose: The first GammaPod™ unit for prone stereotactic treatment of early stage breast cancer has recently been installed and calibrated. Thirty-six rotating circular Co-60 beams focus dose at an isocenter that traverses throughout a breast target via continuous motion of the treatment table. The breast is immobilized and localized using a vacuum-assisted stereotactic cup system that is fixed to the table during treatment. Here we report on system calibration and on verification of geometric and dosimetric accuracy. Methods: Spatial calibration involves setting the origin of each table translational axis within the treatment control system such that the relationship between beam isocenter and table geometry is consistent with that assumed by the treatment planning system. A polyethylene QA breast phantom inserted into an aperture in the patient couch is used for calibration and verification. The comparison is performed via fiducial-based registration of measured single-isocenter dose profiles (radiochromic film) with kernel dose profiles. With the table calibrations applied, measured relative dose distributions were compared with TPS calculations for single-isocenter and dynamic (many-isocenter) treatment plans. Further, table motion accuracy and linearity was tested via comparison of planned control points with independent encoder readouts. Results: After table calibration, comparison of measured and calculated single-isocenter dose profiles show agreement to within 0.5 mm for each axis. Gamma analysis of measured vs calculated profiles with 3%/2mm criteria yields a passing rate of >99% and >98% for single-isocenter and dynamic plans respectively. This also validates the relative dose distributions produced by the TPS. Measured table motion accuracy was within 0.05 mm for all translational axes. Conclusion: GammaPod table coordinate calibration is a straightforward process that yields very good agreement between planned and measured relative dose distributions

  1. Visualization and volumetric structures from MR images of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Parvin, B.; Johnston, W.; Robertson, D.

    1994-03-01

    Pinta is a system for segmentation and visualization of anatomical structures obtained from serial sections reconstructed from magnetic resonance imaging. The system approaches the segmentation problem by assigning each volumetric region to an anatomical structure. This is accomplished by satisfying constraints at the pixel level, slice level, and volumetric level. Each slice is represented by an attributed graph, where nodes correspond to regions and links correspond to the relations between regions. These regions are obtained by grouping pixels based on similarity and proximity. The slice level attributed graphs are then coerced to form a volumetric attributed graph, where volumetric consistency can be verified. The main novelty of our approach is in the use of the volumetric graph to ensure consistency from symbolic representations obtained from individual slices. In this fashion, the system allows errors to be made at the slice level, yet removes them when the volumetric consistency cannot be verified. Once the segmentation is complete, the 3D surfaces of the brain can be constructed and visualized.

  2. Pose Self-Calibration of Stereo Vision Systems for Autonomous Vehicle Applications

    Directory of Open Access Journals (Sweden)

    Basam Musleh

    2016-09-01

    Full Text Available Nowadays, intelligent systems applied to vehicles have grown very rapidly; their goal is not only the improvement of safety, but also making autonomous driving possible. Many of these intelligent systems are based on making use of computer vision in order to know the environment and act accordingly. It is of great importance to be able to estimate the pose of the vision system because the measurement matching between the perception system (pixels and the vehicle environment (meters depends on the relative position between the perception system and the environment. A new method of camera pose estimation for stereo systems is presented in this paper, whose main contribution regarding the state of the art on the subject is the estimation of the pitch angle without being affected by the roll angle. The validation of the self-calibration method is accomplished by comparing it with relevant methods of camera pose estimation, where a synthetic sequence is used in order to measure the continuous error with a ground truth. This validation is enriched by the experimental results of the method in real traffic environments.

  3. Pose Self-Calibration of Stereo Vision Systems for Autonomous Vehicle Applications.

    Science.gov (United States)

    Musleh, Basam; Martín, David; Armingol, José María; de la Escalera, Arturo

    2016-09-14

    Nowadays, intelligent systems applied to vehicles have grown very rapidly; their goal is not only the improvement of safety, but also making autonomous driving possible. Many of these intelligent systems are based on making use of computer vision in order to know the environment and act accordingly. It is of great importance to be able to estimate the pose of the vision system because the measurement matching between the perception system (pixels) and the vehicle environment (meters) depends on the relative position between the perception system and the environment. A new method of camera pose estimation for stereo systems is presented in this paper, whose main contribution regarding the state of the art on the subject is the estimation of the pitch angle without being affected by the roll angle. The validation of the self-calibration method is accomplished by comparing it with relevant methods of camera pose estimation, where a synthetic sequence is used in order to measure the continuous error with a ground truth. This validation is enriched by the experimental results of the method in real traffic environments.

  4. Linac-based extracranial radiosurgery with Elekta volumetric modulated arc therapy and an anatomy-based treatment planning system: Feasibility and initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Cilla, Savino, E-mail: savinocilla@gmail.com [Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Deodato, Francesco; Macchia, Gabriella; Digesù, Cinzia [Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Ianiro, Anna; Viola, Pietro; Craus, Maurizio [Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Valentini, Vincenzo [Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Università Cattolica del Sacro Cuore, Campobasso (Italy); Radiation Oncology Unit, Policlinico Universitario “A. Gemelli”, Università Cattolica del Sacro Cuore, Roma (Italy); Piermattei, Angelo [Medical Physics Unit, Policlinico Universitario “A. Gemelli”, Università Cattolica del Sacro Cuore, Roma (Italy); Morganti, Alessio G. [Radiation Oncology Unit, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, S. Orsola-Malpighi Hospital, University of Bologna, Bologna (Italy)

    2016-07-01

    We reported our initial experience in using Elekta volumetric modulated arc therapy (VMAT) and an anatomy-based treatment planning system (TPS) for single high-dose radiosurgery (SRS-VMAT) of liver metastases. This study included a cohort of 12 patients treated with a 26-Gy single fraction. Single-arc VMAT plans were generated with Ergo++ TPS. The prescription isodose surface (IDS) was selected to fulfill the 2 following criteria: 95% of planning target volume (PTV) reached 100% of the prescription dose and 99% of PTV reached a minimum of 90% of prescription dose. A 1-mm multileaf collimator (MLC) block margin was added around the PTV. For a comparison of dose distributions with literature data, several conformity indexes (conformity index [CI], conformation number [CN], and gradient index [GI]) were calculated. Treatment efficiency and pretreatment dosimetric verification were assessed. Early clinical data were also reported. Our results reported that target and organ-at-risk objectives were met for all patients. Mean and maximum doses to PTVs were on average 112.9% and 121.5% of prescribed dose, respectively. A very high degree of dose conformity was obtained, with CI, CN, and GI average values equal to 1.29, 0.80, and 3.63, respectively. The beam-on-time was on average 9.3 minutes, i.e., 0.36 min/Gy. The mean number of monitor units was 3162, i.e., 121.6 MU/Gy. Pretreatment verification (3%-3 mm) showed an optimal agreement with calculated values; mean γ value was 0.27 and 98.2% of measured points resulted with γ < 1. With a median follow-up of 16 months complete response was observed in 12/14 (86%) lesions; partial response was observed in 2/14 (14%) lesions. No radiation-induced liver disease (RILD) was observed in any patients as well no duodenal ulceration or esophagitis or gastric hemorrhage. In conclusion, this analysis demonstrated the feasibility and the appropriateness of high-dose single-fraction SRS-VMAT in liver metastases performed with Elekta

  5. Floating volumetric image formation using a dihedral corner reflector array device.

    Science.gov (United States)

    Miyazaki, Daisuke; Hirano, Noboru; Maeda, Yuki; Yamamoto, Siori; Mukai, Takaaki; Maekawa, Satoshi

    2013-01-01

    A volumetric display system using an optical imaging device consisting of numerous dihedral corner reflectors placed perpendicular to the surface of a metal plate is proposed. Image formation by the dihedral corner reflector array (DCRA) is free from distortion and focal length. In the proposed volumetric display system, a two-dimensional real image is moved by a mirror scanner to scan a three-dimensional (3D) space. Cross-sectional images of a 3D object are displayed in accordance with the position of the image plane. A volumetric image is observed as a stack of the cross-sectional images. The use of the DCRA brings compact system configuration and volumetric real image generation with very low distortion. An experimental volumetric display system including a DCRA, a galvanometer mirror, and a digital micro-mirror device was constructed to verify the proposed method. A volumetric image consisting of 1024×768×400 voxels was formed by the experimental system.

  6. World Calibration Center for SF6 - supporting the quality system of the global atmosphere observation

    Science.gov (United States)

    Lee, J.; Moon, D.; Min, D.; Yun, W.

    2012-10-01

    According to the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Strategic Plan: 2008-2015 (WMO, 2009a) WMO/GAW pays attention to systematical improvement of the quality of observations at global or regional monitoring sites. To ensure the comparability and compatibility of the measurements worldwide it is essential to maintain a traceability chain to the primary standard in the different laboratories around the world as well as to establish a quality control system. Sulfur hexafluoride (SF6), is reported to be very rare in the atmosphere at the global averaged annual mole fraction of about 7 ppt, it is one of the greenhouse gases regulated by Kyoto protocol and is increasing at a rate of 0.22 ppt yr-1. Development of a working (or transfer) standard with very low concentration of SF6 requires expert technologies and several knowhow of gas metrology. In order to meet the Data Quality Objective (DQO), the KMA has cooperated with the Korea Research Institute of Standards and Science (KRISS), which is the National Metrology Institute in South Korea. So long as the Central Calibration Laboratory (CCL) for SF6 was established, the Korea Meteorological Administration (KMA) is now trying to take another step forward to systematically support GAW stations in improving their traceability and quality system for SF6, thereby making a contribution to the WMO/GAW. Through hosting the World Calibration Center for SF6, which is one of GAW facilities, KMA will contribute to harmonization of the global SF6 observations in the long run. This work performed to demonstrate some measurement results on SF6 which complies with the DQOs and is traceable to the WMO mole fraction scale for SF6. In order to produce a working standard which is traceable to the WMO scale, we developed highly precise method of a Gas Chromatography/Electron Capture Detector (GC/ECD) calibrated against the five cylinders (from NOAA, 2011) of the WMO scale. For all analysis the measurement

  7. World Calibration Center for SF6 – supporting the quality system of the global atmosphere observation

    Directory of Open Access Journals (Sweden)

    W. Yun

    2012-10-01

    Full Text Available According to the World Meteorological Organization (WMO Global Atmosphere Watch (GAW Strategic Plan: 2008–2015 (WMO, 2009a WMO/GAW pays attention to systematical improvement of the quality of observations at global or regional monitoring sites. To ensure the comparability and compatibility of the measurements worldwide it is essential to maintain a traceability chain to the primary standard in the different laboratories around the world as well as to establish a quality control system. Sulfur hexafluoride (SF6, is reported to be very rare in the atmosphere at the global averaged annual mole fraction of about 7 ppt, it is one of the greenhouse gases regulated by Kyoto protocol and is increasing at a rate of 0.22 ppt yr−1. Development of a working (or transfer standard with very low concentration of SF6 requires expert technologies and several knowhow of gas metrology. In order to meet the Data Quality Objective (DQO, the KMA has cooperated with the Korea Research Institute of Standards and Science (KRISS, which is the National Metrology Institute in South Korea. So long as the Central Calibration Laboratory (CCL for SF6 was established, the Korea Meteorological Administration (KMA is now trying to take another step forward to systematically support GAW stations in improving their traceability and quality system for SF6, thereby making a contribution to the WMO/GAW. Through hosting the World Calibration Center for SF6, which is one of GAW facilities, KMA will contribute to harmonization of the global SF6 observations in the long run. This work performed to demonstrate some measurement results on SF6 which complies with the DQOs and is traceable to the WMO mole fraction scale for SF6. In order to produce a working standard which is traceable to the WMO scale, we developed highly precise method of a Gas Chromatography/Electron Capture Detector (GC/ECD calibrated against the five cylinders (from NOAA, 2011 of the WMO scale. For all analysis the

  8. A Measuring System for Well Logging Attitude and a Method of Sensor Calibration

    Directory of Open Access Journals (Sweden)

    Yong Ren

    2014-05-01

    Full Text Available This paper proposes an approach for measuring the azimuth angle and tilt angle of underground drilling tools with a MEMS three-axis accelerometer and a three-axis fluxgate sensor. A mathematical model of well logging attitude angle is deduced based on combining space coordinate transformations and algebraic equations. In addition, a system implementation plan of the inclinometer is given in this paper, which features low cost, small volume and integration. Aiming at the sensor and assembly errors, this paper analyses the sources of errors, and establishes two mathematical models of errors and calculates related parameters to achieve sensor calibration. The results show that this scheme can obtain a stable and high precision azimuth angle and tilt angle of drilling tools, with the deviation of the former less than ±1.4° and the deviation of the latter less than ±0.1°.

  9. A measuring system for well logging attitude and a method of sensor calibration.

    Science.gov (United States)

    Ren, Yong; Wang, Yangdong; Wang, Mijian; Wu, Sheng; Wei, Biao

    2014-05-23

    This paper proposes an approach for measuring the azimuth angle and tilt angle of underground drilling tools with a MEMS three-axis accelerometer and a three-axis fluxgate sensor. A mathematical model of well logging attitude angle is deduced based on combining space coordinate transformations and algebraic equations. In addition, a system implementation plan of the inclinometer is given in this paper, which features low cost, small volume and integration. Aiming at the sensor and assembly errors, this paper analyses the sources of errors, and establishes two mathematical models of errors and calculates related parameters to achieve sensor calibration. The results show that this scheme can obtain a stable and high precision azimuth angle and tilt angle of drilling tools, with the deviation of the former less than ±1.4° and the deviation of the latter less than ±0.1°.

  10. In-flight calibration of STEREO-B/WAVES antenna system

    CERN Document Server

    Panchenko, M; Rucker, H O; Fischer, G; Oswald, T H; Cecconi, B; Maksimovic, M

    2015-01-01

    The STEREO/WAVES (SWAVES) experiment on board the two STEREO spacecraft (Solar Terrestrial Relations Observatory) launched on 25 October 2006 is dedicated to the measurement of the radio spectrum at frequencies between a few kilohertz and 16 MHz. The SWAVES antenna system consists of 6 m long orthogonal monopoles designed to measure the electric component of the radio waves. With this configuration direction finding of radio sources and polarimetry (analysis of the polarization state) of incident radio waves is possible. For the evaluation of the SWAVES data the receiving properties of the antennas, distorted by the radiation coupling with the spacecraft body and other onboard devices, have to be known accurately. In the present context, these properties are described by the antenna effective length vectors. We present the results of an in-flight calibration of the SWAVES antennas using the observations of the nonthermal terrestrial auroral kilometric radiation (AKR) during STEREO roll maneuvers in an early s...

  11. Towards a full Atmospheric Calibration system for the Cherenkov Telescope Array

    CERN Document Server

    Doro, M; Blanch, O; Font, LL; Garrido, D; Lopez-Oramas, A

    2013-01-01

    The current generation of Cherenkov telescopes is mainly limited in their gamma-ray energy and flux reconstruction by uncertainties in the determination of atmospheric parameters. The Cherenkov Telescope Array (CTA) aims to provide high-precision data extending the duty cycle as much as possible. To reach this goal, it is necessary to continuously and precisely monitor the atmosphere by means of remote-sensing devices, which are able to provide altitude-resolved and wavelength-dependent extinction factors, sensitive up to the tropopause and higher. Raman LIDARs are currently the best suited technology to achieve this goal with one single instrument. However, the synergy with other instruments like radiometers, solar and stellar photometers, all-sky cameras, and possibly radio-sondes is desirable in order to provide more precise and accurate results, and allows for weather forecasts and now-casts. In this contribution, we will discuss the need and features of such multifaceted atmospheric calibration systems.

  12. Development and calibration of a MFM-based system for local hysteresis loops measurements

    Science.gov (United States)

    Coïsson, M.; Barrera, G.; Celegato, F.; Tiberto, P.

    2016-10-01

    A measurement technique derived from a field-dependent magnetic force microscope (MFM) is presented for the measurement of local hysteresis loops on patterned micrometric and sub-micrometric magnetic structures. The technique exploits the synchronisation of the applied field variations with the end-of-line signal of the microscope, while keeping the slow scan axis disabled. In this way, a single MFM image contains the whole field evolution of the magnetisation processes in the sample along a user-defined profile. An analysis procedure is presented for the subsequent determination of local hysteresis loops on magnetic dots. The system has been calibrated for what concerns the applied field values. No significant artifacts induced in the measurements by the applied field have been observed up to applied fields of ≈ 1000 Oe.

  13. Color Calibration for Colorized Vision System with Digital Sensor and LED Array Illuminator

    Directory of Open Access Journals (Sweden)

    Zhenmin Zhu

    2016-01-01

    Full Text Available Color measurement by the colorized vision system is a superior method to achieve the evaluation of color objectively and continuously. However, the accuracy of color measurement is influenced by the spectral responses of digital sensor and the spectral mismatch of illumination. In this paper, two-color vision system illuminated by digital sensor and LED array, respectively, is presented. The Polynomial-Based Regression method is applied to solve the problem of color calibration in the sRGB and CIE  L⁎a⁎b⁎ color spaces. By mapping the tristimulus values from RGB to sRGB color space, color difference between the estimated values and the reference values is less than 3ΔE. Additionally, the mapping matrix ΦRGB→sRGB has proved a better performance in reducing the color difference, and it is introduced subsequently into the colorized vision system proposed for a better color measurement. Necessarily, the printed matter of clothes and the colored ceramic tile are chosen as the application experiment samples of our colorized vision system. As shown in the experimental data, the average color difference of images is less than 6ΔE. It indicates that a better performance of color measurement is obtained via the colorized vision system proposed.

  14. The System of the Calibration for Visibility Measurement Instrument Under the Atmospheric Aerosol Simulation Environment

    Directory of Open Access Journals (Sweden)

    Shu Zhifeng

    2016-01-01

    Full Text Available Visibility is one of the most important parameters for meteorological observation and numerical weather prediction (NWP.It is also an important factor in everyday life, mainly for surface and air traffic especially in the Aeronautical Meteorology. The visibility decides the taking off and landing of aircraft. If the airport visibility is lower than requirement for aircraft taking off stipulated by International Civil Aviation Administration, then the aircraft must be parked at the airport. So the accurate measurement of visibility is very important. Nowadays, many devices can be measured the visibility or meteorological optical range (MOR such as Scatterometers, Transmissometers and visibility lidar. But there is not effective way to verify the accuracy of these devices expect the artificial visual method. We have developed a visibility testing system that can be calibration and verification these devices. The system consists of laser transmitter, optical chopper, phase-locking amplifier, the moving optic receiving system, signal detection and data acquisition system, atmospheric aerosol simulation chamber. All of them were placed in the atmosphere aerosol simulation chamber with uniform aerosol concentration. The Continuous wave laser, wavelength 550nm, has been transmitted into the collimation system then the laser beam expanded into 40mm diameter for compressing the laser divergence angle before modulated by optical chopper. The expanding beam transmitting in the atmosphere aerosol cabin received by the optic receiving system moving in the 50m length precision guide with 100mm optical aperture. The data of laser signal has been acquired by phase-locking amplifier every 5 meter range. So the 10 data points can be detected in the 50 meters guide once. The slope of the fitting curve can be obtained by linear fitting these data using the least square method. The laser extinction coefficient was calculated from the slope using the Koschmieder

  15. Modeling and calibration of pulse-modulation based ToF imaging systems

    Science.gov (United States)

    Süss, Andreas; Varga, Gabor; Marx, Michael; Fürst, Peter; Gläsener, Stefan; Tiedke, Wolfram; Jung, Melanie; Spickermann, Andreas; Hosticka, Bedrich J.

    2016-03-01

    Conversely to the continuous wave indirect time-of-flight (CW-iToF) imaging scheme, pulsed modulation ToF (PM-iToF) imaging is a promising depth measurement technique for operation at high ambient illumination. It is known that non-linearity and finite charge-transfer speed impact trueness and precision of ToF systems.1-3 As pulses are no Eigenfunctions to the shutter system, this issue is especially pronounced in pulsed modulation.2, 3 Despite these effects, it is possible to find analytical expressions founded on physical observations that map scenery parameters such as depth information, reflectance and ambient light level to sensor output.3, 4 In the application, the inverse of this map has to be evaluated. In PM-iToF, an inverse function cannot be yielded in a direct manner, as models proposed in the literature were transcendental.3, 4 For a limited range an approximating linearization can be performed to yield depth information.5 To extend the usable range, recently, an alternative approach that indirectly approximates the inverse function was presented.6 This method was founded on 1D doping concentration profiles, which, however, are typically not made available to end users. Also, limitations of the 1D approximation as well as stability are yet to be explored. This work presents a calibration methodology that copes with detector insufficiencies such as finite charge transfer speed. Contrarily to the state of the art, no prior knowledge on details of the underlying devices is required. The work covers measurement setup, a benchmark of various calibration schemes and deals with issues such as overfitting or defect pixels.

  16. Calibration of a PIXE system for analysis of environmental aerosols; Calibracion de un sistema PIXE para analisis de aerosoles ambientales

    Energy Technology Data Exchange (ETDEWEB)

    Aldape, F.; Diaz, R.V.; Anguiano, G.; Flores M, J. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1991-04-15

    The results of the calibration of the PIXE system for analysis of environmental aerosols in the CNM is presented. The system was calibrated in order to lead to the project study of environmental aerosols using PIXE from the qualitative dimension to the quantitative one. Part of this work it was carried out in collaboration with the expert of the IAEA Dr. D. Crumpton. The calibration of the system it was achieved bombarding thin targets of well-known composition with protons of 2.5 MeV. Using this technique it was determined the absolute elementary concentration in samples of atmospheric aerosols. As an example the calculation of the lead concentration in one of them whose result was of 662 {+-} 49 ng m{sup -3} is presented. This value agrees with the measurements made in the Crocker Nuclear Lab of the UCD. Its are also discussed the reproducibility and precision of the used technique. (Author)

  17. Modified calibration procedures for a Yankee Environmental System UVB-1 biometer based on spectral measurements with a brewer spectrophotometer.

    Science.gov (United States)

    Vilaplana, José M; Cachorro, Victoria E; Sorribas, Mar; Luccini, Eduardo; de Frutos, Angel M; Berjón, Alberto; de la Morena, Benito

    2006-01-01

    The calibration of the erythemal irradiance measured by a Yankee Environmental System (YES) UVB-1 biometer is presented using two methods of calibration with a wide range of experimental solar zenith angles (SZAs) and ozone values. The calibration is performed through simultaneous spectral measurements by a calibrated double-monochromator Brewer MK-III spectrophotometer at "El Arenosillo" station, located in southwestern Spain. Because the range of spectral measurements of the Brewer spectrophotometer is 290-363 nm, a previously validated radiative transfer model was used to account for the erythemal contribution between 363 and 400 nm. Both methods are recommended by the World Meteorological Organization and we present and discuss here a wide range of results and features given by modified procedures applied to these two general methods. As is well established, the calibration factor for this type of radiometric system is dependent on atmospheric conditions, the most important of which are the ozone content and the SZA. Although the first method is insensitive to these two factors, we analyze this behavior in terms of the range used for the SZA and the use of two different mathematical approaches for its determination. The second method shows the dependence on SZA and ozone content and, thus, a polynomial as a function of SZA or a matrix including SZA and ozone content were determined as general calibration factors for the UV radiometric system. We must note that the angular responses of the YES radiometer and Brewer spectroradiometer have not been considered, because of the difficulty in correcting them. The results show in detail the advantages and drawbacks (and the corresponding associated error) given by the different approaches used for the determination of these calibration coefficients.

  18. A hardware-software system for the automation of verification and calibration of oil metering units secondary equipment

    Science.gov (United States)

    Boyarnikov, A. V.; Boyarnikova, L. V.; Kozhushko, A. A.; Sekachev, A. F.

    2017-08-01

    In the article the process of verification (calibration) of oil metering units secondary equipment is considered. The purpose of the work is to increase the reliability and reduce the complexity of this process by developing a software and hardware system that provides automated verification and calibration. The hardware part of this complex carries out the commutation of the measuring channels of the verified controller and the reference channels of the calibrator in accordance with the introduced algorithm. The developed software allows controlling the commutation of channels, setting values on the calibrator, reading the measured data from the controller, calculating errors and compiling protocols. This system can be used for checking the controllers of the secondary equipment of the oil metering units in the automatic verification mode (with the open communication protocol) or in the semi-automatic verification mode (without it). The peculiar feature of the approach used is the development of a universal signal switch operating under software control, which can be configured for various verification methods (calibration), which allows to cover the entire range of controllers of metering units secondary equipment. The use of automatic verification with the help of a hardware and software system allows to shorten the verification time by 5-10 times and to increase the reliability of measurements, excluding the influence of the human factor.

  19. [Research on On-Line Calibration Based Photoacoustic Spectrometry System for Monitoring the Concentration of CO2 in Atmosphere].

    Science.gov (United States)

    Zhang, Jian-feng; Pan, Sun-qiang; Lin, Xiao-lu; Hu, Peng-bing; Chen, Zhe-min

    2016-01-01

    Resonate frequency and cell constant of photoacoustic spectrum system are usually calibrated by using standard gas in laboratory, whereas the resonate frequency and cell constant will be changed in-situ, leading to measurement accuracy errors, caused by uncertainties of standard gas, differences between standard and measured gas components and changes in environmental condition, such as temperature and humidity. As to overcome the above problems, we have proposed an on-line atmospheric oxygen-based calibration technology for photoacoustic spectrum system and used in measurement of concentration of carbon dioxide in atmosphere. As the concentration of atmospheric oxygen is kept as constant as 20.96%, the on-line calibration for the photoacoustic spectrum system can be realized by detecting the swept-frequency and peak signal at 763.73 nm. The cell of the PAS has a cavity with length of 100 mm and an inner diameter of 6 mm, and worked in a first longitudinal resonant mode. The influence of environmental temperature and humidity, gas components on the photoacoustic cell's performance has been theoretically analyzed, and meanwhile the resonant frequencies and cell constants were calibrated and acquired respectively using standard gas, indoor air and outdoor air. Compared with calibrated gas analyzer, concentration of carbon dioxide is more accurate by using the resonant frequency and cell constant calculated by oxygen in tested air, of which the relative error is less than 1%, much smaller than that calculated by the standard gas in laboratory. The innovation of this paper is that using atmospheric oxygen as photoacoustic spectrum system's calibration gas effectively reduces the error caused by using standard gas and environmental condition changes, and thus improves the on-line measuring accuracy and reliability of the photoacoustic spectrum system.

  20. Volumetric composition in composites and historical data

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2013-01-01

    guidance to the optimal combination of fibre content, matrix content and porosity content, in order to achieve the best obtainable properties. Several composite materials systems have been shown to be handleable with this model. An extensive series of experimental data for the system of cellulose fibres...... and polymer (resin) was produced in 1942 – 1944, and these data have been (re-)analysed by the volumetric composition model, and the property values for density, stiffness and strength have been evaluated. Good agreement has been obtained and some further observations have been extracted from the analysis....

  1. The upgraded calibration system for the scintillator-PMT Tile Hadronic Calorimeter of the ATLAS experiment at CERN/LHC

    CERN Document Server

    Chakraborty, Dhiman; The ATLAS collaboration

    2017-01-01

    The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy in highest energy proton-proton and heavy-ion collisions at CERN’s Large Hadron Collider. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes (PMTs) located on the outside of the calorimeter. The readout is segmented into about 5000 cells (longitudinally and transversally), each read out by two PMTs in parallel. A multi-component calibration system is employed to calibrate and monitor the stability and performance of each part of the readout chain during data taking. The TileCal calibration system comprises Cesium radioactive sources, laser and charge injection elements and it allows to monitor and ...

  2. The Upgraded Calibration System for the Scintillator-PMT Tile Hadronic Calorimeter of the ATLAS experiment at CERN/LHC

    CERN Document Server

    Chakraborty, Dhiman; The ATLAS collaboration

    2017-01-01

    The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment and provides important information for reconstruction of hadrons, jets, hadronic decays of tau leptons and missing transverse energy in highest energy proton-proton and heavy-ion collisions at CERN’s Large Hadron Collider. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photomultiplier tubes (PMTs) located on the outside of the calorimeter. The readout is segmented into about 5000 cells (longitudinally and transversally), each read out by two PMTs in parallel. A multi-component calibration system is employed to calibrate and monitor the stability and performance of each part of the readout chain during data taking. The TileCal calibration system comprises Cesium radioactive sources, laser and charge injection elements and it allows to monitor and ...

  3. Calibration and Data Quality systems of the ATLAS Tile Calorimeter during the LHC Run-I operations

    CERN Document Server

    Zenis, Tibor; The ATLAS collaboration

    2015-01-01

    The Tile Calorimeter is the hadronic calorimeter covering the central region of the ATLAS detector at the LHC. It consists of thin steel plates and scintillating tiles. Wavelength shifting fibres coupled to the tiles collect the produced light and are read out by photomultiplier tubes. The calibration scheme of the Tile Calorimeter comprises Cs radioactive source, laser and charge injection systems. Each stage of the signal production of the calorimeter from scintillation light to digitization is monitored and equalized. Description of the different TileCal calibration systems as well as results on their performance in terms of calibration factors, linearity and stability will be given. The data quality procedures and data quality efficiency of the Tile Calorimeter during the LHC data-taking period are presented as well.

  4. Calibration and Data Quality systems of the ATLAS Tile Calorimeter during the LHC Run-I operations

    CERN Document Server

    Zenis, Tibor; The ATLAS collaboration

    2015-01-01

    The Tile Calorimeter is the hadronic calorimeter covering the central region of the ATLAS detector at the LHC. It consists of thin steel plates and scintillating tiles. Wavelength shifting fibres coupled to the tiles collect the produced light and are read out by photomultiplier tubes. The calibration scheme of the Tile Calorimeter comprises Cs radioactive source, laser and charge injection systems. Each stage of the signal production of the calorimeter from scintillation light to digitization is monitored and equalized. Description of the different TileCal calibration systems as well as the results on their performance in terms of calibration factors, linearity and stability are given. The data quality procedures and data quality efficiency of the Tile Calorimeter during the LHC data-taking period are presented as well.

  5. View-dependent geometric calibration for offset flat-panel cone beam computed tomography systems

    Science.gov (United States)

    Nguyen, Van-Giang

    2016-04-01

    Geometric parameters that define the geometry of imaging systems are crucial for image reconstruction and image quality in x-ray computed tomography (CT). The problem of determining geometric parameters for an offset flat-panel cone beam CT (CBCT) system, a recently introduced modality with a large field of view, with the assumption of an unstable mechanism and geometric parameters that vary in each view, is considered. To accurately and rapidly find the geometric parameters for each projection view, we use the projection matrix method and design a dedicated phantom that is partially visible in all projection views. The phantom consists of balls distributed symmetrically in a cylinder to ensure the inclusion of the phantom in all views, and a large portion of the phantom is covered in the projection image. To efficiently use calibrated geometric information in the reconstruction process and get rid of approximation errors, instead of decomposing the projection matrix into actual geometric parameters that are manually corrected before being used in reconstruction, as in conventional methods, we directly use the projection matrix and its pseudo-inverse in projection and backprojection operations of reconstruction algorithms. The experiments illustrate the efficacy of the proposed method with a real offset flat-panel CBCT system in dental imaging.

  6. The uBVI Photometric System. I. Motivation, Implementation, and Calibration

    CERN Document Server

    Bond, H E

    2005-01-01

    This paper describes the design principles for a CCD-based photometric system that is highly optimized for ground-based measurement of the size of the Balmer jump in stellar energy distributions. It is shown that, among ultraviolet filters in common use, the Thuan-Gunn u filter is the most efficient for this purpose. This filter is combined with the standard Johnson-Kron-Cousins B, V, and I bandpasses to constitute the uBVI photometric system. Model stellar atmospheres are used to calibrate color-color diagrams for the uBVI system in terms of the fundamental stellar parameters of effective temperature, surface gravity, and metallicity. The u-B index is very sensitive to log g, but also to [Fe/H]. It is shown that an analog of the Str\\"omgren c_1 index, defined as (u-B)-(B-V), is much less metallicity dependent, but still sensitive to log g. The effect of interstellar reddening on u-B is determined through synthetic photometric calculations, and practical advice is given on dealing with flat fields, atmospheri...

  7. A Training Program Using an Audience Response System to Calibrate Dental Faculty Members Assessing Student Clinical Competence.

    Science.gov (United States)

    Metz, Michael J; Metz, Cynthia J; Durski, Marcelo T; Aiken, Sean A; Mayfield, Theresa G; Lin, Wei-Shao

    2016-09-01

    The aim of this study was to assess the effectiveness of calibration training of departmental faculty and competency graders using an audience response system on operative dentistry concepts across 12 months. The training sessions were designed to further solidify the process and equilibration of clinical opinions among faculty members and provide a more calibrated grading assessment during patient care for student performance feedback. Four (quarterly) calibration sessions occurred over 12 months in 2015. The first session was considered the baseline (control value) for this study. Pre- and post-calibration interrater agreement was assessed. Additionally, a pre and post assessment with ten Likert-scale questions was used to measure students' perceptions of instructional consistency. The results showed that a statistically significant increase in conceptual knowledge scores occurred for both departmental faculty members and competency graders across each of the four sessions (one-factor ANOVA; paudience response system for departmental and competency graders was found to be effective in facilitating a discussion forum, calibrating clinical assessments, and improving student perceptions. The positive results from this study support the value of dental schools' introducing faculty development programs to ensure consistent instruction for assessing dental student competence.

  8. Evaluation of Instrument Landing System DDM (Difference in Depth of Modulation) Calibration Accuracies.

    Science.gov (United States)

    1983-12-01

    provided invaluable help in the development and completion of this thesis project. Sincere appreciation is expressed to Mr. William E. Herod , Chief of...0.01728 :I ; Fig. IV-13. Calibration Hierarchy & Accuracies. IV-18 L Ley ’ ! It is clear that if the calibration accuracies of figure IV-13 can be

  9. Calibration Standards for Surface Topography Measuring Systems down to Nanometric Range

    DEFF Research Database (Denmark)

    Trumpold, H.; De Chiffre, Leonardo; Andreasen, Jan Lasson

    calibrator has been designed, built and tested. Primary calibration standards have been produced by ion-beam and plasma etching (step height standards), by holographic generation of sinusoidal structures with two-beam interference exposure and by ultra-precision diamond cutting. From primary standards...

  10. In vivo evaluation of three-dimensional of volumetric changes using a CAD/CAM chair-side system: Technical procedure

    Science.gov (United States)

    Ferreiroa, Alberto; Pascual-Moscardó, Agustín; Fons-Font, Antonio; Solá-Ruíz, María-Fernanda

    2017-01-01

    An intraoral digital scanner in combination with specialized three-dimensional surface analysis software monitors volumetric changes to soft tissues or dental restorations. This technology can evaluate the success of a specific technique or medium- or long-term clinical outcomes in both clinical and research situations. This article describes how this technology was used to provide immediate chair-side data analysis without the help of specialized laboratory support. Key words:Intraoral scanner, CAD-CAM, best fit-method, surface tessellation language. PMID:28298996

  11. Point Cloud Refinement with a Target-Free Intrinsic Calibration of a Mobile Multi-Beam LIDAR System

    Science.gov (United States)

    Nouiraa, H.; Deschaud, J. E.; Goulettea, F.

    2016-06-01

    LIDAR sensors are widely used in mobile mapping systems. The mobile mapping platforms allow to have fast acquisition in cities for example, which would take much longer with static mapping systems. The LIDAR sensors provide reliable and precise 3D information, which can be used in various applications: mapping of the environment; localization of objects; detection of changes. Also, with the recent developments, multi-beam LIDAR sensors have appeared, and are able to provide a high amount of data with a high level of detail. A mono-beam LIDAR sensor mounted on a mobile platform will have an extrinsic calibration to be done, so the data acquired and registered in the sensor reference frame can be represented in the body reference frame, modeling the mobile system. For a multibeam LIDAR sensor, we can separate its calibration into two distinct parts: on one hand, we have an extrinsic calibration, in common with mono-beam LIDAR sensors, which gives the transformation between the sensor cartesian reference frame and the body reference frame. On the other hand, there is an intrinsic calibration, which gives the relations between the beams of the multi-beam sensor. This calibration depends on a model given by the constructor, but the model can be non optimal, which would bring errors and noise into the acquired point clouds. In the litterature, some optimizations of the calibration parameters are proposed, but need a specific routine or environment, which can be constraining and time-consuming. In this article, we present an automatic method for improving the intrinsic calibration of a multi-beam LIDAR sensor, the Velodyne HDL-32E. The proposed approach does not need any calibration target, and only uses information from the acquired point clouds, which makes it simple and fast to use. Also, a corrected model for the Velodyne sensor is proposed. An energy function which penalizes points far from local planar surfaces is used to optimize the different proposed parameters

  12. Three-dimensional surface imaging by multi-frequency phase shift profilometry with angle and pattern modeling for system calibration

    Science.gov (United States)

    Wang, Zhenzhou

    2016-08-01

    In this paper, we present a 3D surface imaging system based on the well-known phase shift profilometry. To yield the analytical solutions, four shifted phases and three high carrier frequencies are used to compute the phase map and reduce the noises that are caused by the inherent optical aberrations and external influences, e.g. different illumination light sources, uneven intensity distribution and automatic image processing algorithms. To reduce the system noise, we propose to model the pattern of the calibration grid in a virtual space. To obtain the modeled pattern, we use a plane to intercept the rays that are modeled by the proposed angle modeling method. In the world coordinate system, the angle and the pattern are computed based on the calibration data. A registration method is used to transform the modeled pattern in the virtual space to the ideal pattern in the world coordinate system by computing the least squared errors between the true points in the modeled pattern and the measured points in the practical pattern. The modeled (true) points are used for re-calibration of the 3D imaging system. Experimental results showed that the measurement accuracy increases considerably and the MSE is reduced from 0.95 mm to 0.65 mm (32% average error decrease) after replacing the measured points with the true points for calibration.

  13. Trinocular Calibration Method Based on Binocular Calibration

    Directory of Open Access Journals (Sweden)

    CAO Dan-Dan

    2012-10-01

    Full Text Available In order to solve the self-occlusion problem in plane-based multi-camera calibration system and expand the measurement range, a tri-camera vision system based on binocular calibration is proposed. The three cameras are grouped into two pairs, while the public camera is taken as the reference to build the global coordinate. By calibration of the measured absolute distance and the true absolute distance, global calibration is realized. The MRE (mean relative error of the global calibration of the two camera pairs in the experiments can be as low as 0.277% and 0.328% respectively. Experiment results show that this method is feasible, simple and effective, and has high precision.

  14. Cortisol profiles: A test for adaptive calibration of the stress response system in maltreated and nonmaltreated youth

    Science.gov (United States)

    PECKINS, MELISSA K.; SUSMAN, ELIZABETH J.; NEGRIFF, SONYA; NOLL, JENNIE; TRICKETT, PENELOPE K.

    2017-01-01

    Throughout the life span, exposure to chronic stress such as child maltreatment is thought to contribute to future dysfunction of the stress response system (SRS) through the process of adaptive calibration. Dysfunction of the SRS is associated with numerous health and behavior problems, so it is important to understand under what conditions and what time frame adaptive calibration occurs. The present study tested for adaptive calibration of the SRS in a sample of maltreated (n = 303) and nonmaltreated (n = 151) youth during the important developmental period of adolescence. Data were used from Waves 2, 3, and 4 of a larger study of the consequences of maltreatment on health and well-being. At each time point, participants underwent the Trier Social Stress Test for Children and provided a baseline and four poststressor saliva samples to measure cortisol reactivity. Adaptive calibration was tested by performing a latent profile analysis using the five samples of salivary cortisol provided at each time point, and testing whether maltreatment status predicted the likelihood of profile membership at Time 2, Time 3, and Time 4. Three cortisol profiles emerged from the data at each time point (blunted, moderate, and elevated), and results indicated that maltreated youth were more likely than nonmaltreated youth to present with the blunted cortisol profile compared to the moderate and elevated profiles at Time 2 and Time 3, even after controlling for recent exposure to violence and trauma. At Time 4, there was no longer a difference in profile membership between maltreated and nonmaltreated youth, suggesting adaptive calibration may be a lengthy process requiring a period of years to become evident. Overall, the findings provide support for adaptive calibration and offer insight into the conditions under which adaptive calibration occurs. PMID:26535937

  15. Retrievals of Thick Cloud Optical Depth from the Geoscience Laser Altimeter System (GLAS) by Calibration of Solar Background Signal

    Science.gov (United States)

    Yang, Yuekui; Marshak, Alexander; Chiu, J. Christine; Wiscombe, Warren J.; Palm, Stephen P.; Davis, Anthony B.; Spangenberg, Douglas A.; Nguyen, Louis; Spinhirne, James D.; Minnis, Patrick

    2008-01-01

    Laser beams emitted from the Geoscience Laser Altimeter System (GLAS), as well as other space-borne laser instruments, can only penetrate clouds to a limit of a few optical depths. As a result, only optical depths of thinner clouds (thick clouds using solar background light and treating GLAS as a solar radiometer. To do so we first calibrate the reflected solar radiation received by the photon-counting detectors of GLAS' 532 nm channel, which is the primary channel for atmospheric products. The solar background radiation is regarded as a noise to be subtracted in the retrieval process of the lidar products. However, once calibrated, it becomes a signal that can be used in studying the properties of optically thick clouds. In this paper, three calibration methods are presented: (I) calibration with coincident airborne and GLAS observations; (2) calibration with coincident Geostationary Operational Environmental Satellite (GOES) and GLAS observations of deep convective clouds; (3) calibration from the first principles using optical depth of thin water clouds over ocean retrieved by GLAS active remote sensing. Results from the three methods agree well with each other. Cloud optical depth (COD) is retrieved from the calibrated solar background signal using a one-channel retrieval. Comparison with COD retrieved from GOES during GLAS overpasses shows that the average difference between the two retrievals is 24%. As an example, the COD values retrieved from GLAS solar background are illustrated for a marine stratocumulus cloud field that is too thick to be penetrated by the GLAS laser. Based on this study, optical depths for thick clouds will be provided as a supplementary product to the existing operational GLAS cloud products in future GLAS data releases.

  16. Calibration of Geodetic Instruments

    Directory of Open Access Journals (Sweden)

    Marek Bajtala

    2005-06-01

    Full Text Available The problem of metrology and security systems of unification, correctness and standard reproducibilities belong to the preferred requirements of theory and technical practice in geodesy. Requirements on the control and verification of measured instruments and equipments increase and the importance and up-to-date of calibration get into the foreground. Calibration possibilities of length-scales (of electronic rangefinders and angle-scales (of horizontal circles of geodetic instruments. Calibration of electronic rangefinders on the linear comparative baseline in terrain. Primary standard of planar angle – optical traverse and its exploitation for calibration of the horizontal circles of theodolites. The calibration equipment of the Institute of Slovak Metrology in Bratislava. The Calibration process and results from the calibration of horizontal circles of selected geodetic instruments.

  17. Conformal Pad-Printing Electrically Conductive Composites onto Thermoplastic Hemispheres: Toward Sustainable Fabrication of 3-Cents Volumetric Electrically Small Antennas.

    Directory of Open Access Journals (Sweden)

    Haoyi Wu

    Full Text Available Electrically small antennas (ESAs are becoming one of the key components in the compact wireless devices for telecommunications, defence, and aerospace systems, especially for the spherical one whose geometric layout is more closely approaching Chu's limit, thus yielding significant bandwidth improvements relative to the linear and planar counterparts. Yet broad applications of the volumetric ESAs are still hindered since the low cost fabrication has remained a tremendous challenge. Here we report a state-of-the-art technology to transfer electrically conductive composites (ECCs from a planar mould to a volumetric thermoplastic substrate by using pad-printing technology without pattern distortion, benefit from the excellent properties of the ECCs as well as the printing-calibration method that we developed. The antenna samples prepared in this way meet the stringent requirement of an ESA (ka is as low as 0.32 and the antenna efficiency is as high as 57%, suggesting that volumetric electronic components i.e. the antennas can be produced in such a simple, green, and cost-effective way. This work can be of interest for the development of studies on green and high performance wireless communication devices.

  18. Conformal Pad-Printing Electrically Conductive Composites onto Thermoplastic Hemispheres: Toward Sustainable Fabrication of 3-Cents Volumetric Electrically Small Antennas.

    Science.gov (United States)

    Wu, Haoyi; Chiang, Sum Wai; Yang, Cheng; Lin, Ziyin; Liu, Jingping; Moon, Kyoung-Sik; Kang, Feiyu; Li, Bo; Wong, Ching Ping

    2015-01-01

    Electrically small antennas (ESAs) are becoming one of the key components in the compact wireless devices for telecommunications, defence, and aerospace systems, especially for the spherical one whose geometric layout is more closely approaching Chu's limit, thus yielding significant bandwidth improvements relative to the linear and planar counterparts. Yet broad applications of the volumetric ESAs are still hindered since the low cost fabrication has remained a tremendous challenge. Here we report a state-of-the-art technology to transfer electrically conductive composites (ECCs) from a planar mould to a volumetric thermoplastic substrate by using pad-printing technology without pattern distortion, benefit from the excellent properties of the ECCs as well as the printing-calibration method that we developed. The antenna samples prepared in this way meet the stringent requirement of an ESA (ka is as low as 0.32 and the antenna efficiency is as high as 57%), suggesting that volumetric electronic components i.e. the antennas can be produced in such a simple, green, and cost-effective way. This work can be of interest for the development of studies on green and high performance wireless communication devices.

  19. STUDY ON THE LINE SCAN CCD CAMERA CALIBRATION OF VEHICLE-BORNE 3D DATA ACQUISITION SYSTEM

    OpenAIRE

    Han, Y; Yang, B.; F. Zhang

    2012-01-01

    Based on the characters of the line scan CCD camera and the Vehicle-borne 3D data acquisition system, it presented a novel method to calibrate the line Scan Camera (LSC) based on the laser scanner. Using the angle information in the original laser scanner data, combing the principle of the line scan camera, it built a calibration model for LSC and designed some experiment methods to implement that. Using the new model and the special experiment methods it computed out high precision ...

  20. Basic calibrations of the photographic RGU system. III - Intermediate and extreme Population II dwarf stars

    Science.gov (United States)

    Buser, R.; Fenkart, R. P.

    1990-11-01

    This paper presents an extended calibration of the color-magnitude and two-color diagrams and the metal-abundance parameter for the intermediate Population II and the extreme halo dwarfs observed in the Basel Palomar-Schmidt RGU three-color photometric surveys of the galaxy. The calibration covers the metallicity range between values +0.50 and -3.00. It is shown that the calibrations presented are sufficiently accurate to be useful for the future analyses of photographic survey data.

  1. Fiber Bragg gratings strain measuring system and a sensor calibration setup based on mechanical nanomotion transducer

    Science.gov (United States)

    Lazarev, Vladimir A.; Leonov, Stanislav O.; Tarabrin, Mikhail K.; Karasik, Valerii E.

    2017-06-01

    Fiber Bragg grating (FBG) strain sensors are powerful tools for structural health monitoring applications. However, FBG sensor fabrication and packaging processes can lead to a non-linear behavior, that affects the accuracy of the strain measurements. Here we present a novel nondestructive calibration technique for FBG strain sensors that use a mechanical nanomotion transducer. A customized calibration setup was designed based on dovetail-type slideways that were mechanized using a stepping motor. The performance of the FBG strain sensor was investigated through analysis of experimental data, and the calibration curves for the FBG strain sensor are presented.

  2. Volumetric Combustion Diagnostics

    Science.gov (United States)

    2017-01-03

    example involved a measurement campaign in collaboration with researchers at the Air Force Research Laboratory (Drs. Timothy Ombrello and Campbell ...its impact and promote AFOSR’s vision and mission. In this project, the PI has collaborated with Drs. Campbell Carter and Tim Ombrello to perform...Thermal-Fluid Systems, Heat Transfer Engineering, 37(3-4), 359-368, (2016) [9] Y.W. Lin Ma, Qingchun Lei, Wenjiang Xu, Campbell D. Carter, 3D Flame

  3. A balanced calibration of water quantity and quality by multi-objective optimization for integrated water system model

    Science.gov (United States)

    Zhang, Yongyong; Shao, Quanxi; Taylor, John A.

    2016-07-01

    Due to the high interactions among multiple processes in integrated water system models, it is extremely difficult, if not impossible, to achieve reasonable solutions for all objectives by using the traditional step-by-step calibration. In many cases, water quantity and quality are equally important but their objectives in model calibration usually conflict with each other, so it is not a good practice to calibrate one after another. In this study, a combined auto-calibration multi-process approach was proposed for the integrated water system model (HEQM) using a multi-objective evolutionary algorithm. This ensures that the model performance among inseparable or interactive processes could be balanced by users based on the Pareto front. The Huai River Basin, a highly regulated and heavily polluted region of China, was selected as a case study. The hydrological and water quality parameters of HEQM were calibrated simultaneously based on the observed series of runoff and ammonia-nitrogen (NH4-N) concentrations. The results were compared with those of the step-by-step calibration to demonstrate the rationality and feasibility of the multi-objective approach. The results showed that a Pareto optimal front was formed and could be divided into three clear sections based on the elastic coefficient of model performance between NH4-N and runoff, i.e., the dominated section for NH4-N improvement, the trade-off section between NH4-N and runoff, and the dominated section for runoff improvement. The trade-off of model performance between runoff and NH4-N concentration was clear. The results of the step-by-step calibration fell in the dominated section for NH4-N improvement, where just the optimum of the runoff simulation was achieved with a large potential to improve NH4-N simulation without a significant degradation of the runoff simulation. The overall optimal solutions for all the simulations appeared in the trade-off section. Therefore, the Pareto front provided different

  4. Combined use of a priori data for fast system self-calibration of a non-rigid multi-camera fringe projection system

    Science.gov (United States)

    Stavroulakis, Petros I.; Chen, Shuxiao; Sims-Waterhouse, Danny; Piano, Samanta; Southon, Nicholas; Bointon, Patrick; Leach, Richard

    2017-06-01

    In non-rigid fringe projection 3D measurement systems, where either the camera or projector setup can change significantly between measurements or the object needs to be tracked, self-calibration has to be carried out frequently to keep the measurements accurate1. In fringe projection systems, it is common to use methods developed initially for photogrammetry for the calibration of the camera(s) in the system in terms of extrinsic and intrinsic parameters. To calibrate the projector(s) an extra correspondence between a pre-calibrated camera and an image created by the projector is performed. These recalibration steps are usually time consuming and involve the measurement of calibrated patterns on planes, before the actual object can continue to be measured after a motion of a camera or projector has been introduced in the setup and hence do not facilitate fast 3D measurement of objects when frequent experimental setup changes are necessary. By employing and combining a priori information via inverse rendering, on-board sensors, deep learning and leveraging a graphics processor unit (GPU), we assess a fine camera pose estimation method which is based on optimising the rendering of a model of a scene and the object to match the view from the camera. We find that the success of this calibration pipeline can be greatly improved by using adequate a priori information from the aforementioned sources.

  5. Development and Uncertainty Evaluation of Calibrating System for Digital Energy Setting

    Directory of Open Access Journals (Sweden)

    Zhao Sha

    2016-01-01

    Full Text Available The power measurement mode has made fundamental changes with the development of smart substation, traditional energy metering analog devices are replaced by digital devices according to the requirements of digitalized information substation. Creating traceability between digital measuring value and analog measuring value and developing relevant calibration devices are key issues in smart substation construction. A new device for calibration digital energy meters using integral calibration technology is described in this paper. Based on the Standard Comparison Method, the device establishes a connection between the digital power and the traditional analog power with the integral calibration technology, and solves the problem that digital power was not able to be traced. The device is designed with final measuring voltage level: 220kV/110kV, measuring current range: 5A~5000A, and extended uncertainty less than 0.05%. Furthermore, the estimating process of the uncertainty of the device is discussed emphatically.

  6. Calibration of robot tool centre point using camera-based system

    Directory of Open Access Journals (Sweden)

    Gordić Zaviša

    2016-01-01

    Full Text Available Robot Tool Centre Point (TCP calibration problem is of great importance for a number of industrial applications, and it is well known both in theory and in practice. Although various techniques have been proposed for solving this problem, they mostly require tool jogging or long processing time, both of which affect process performance by extending cycle time. This paper presents an innovative way of TCP calibration using a set of two cameras. The robot tool is placed in an area where images in two orthogonal planes are acquired using cameras. Using robust pattern recognition, even deformed tool can be identified on images, and information about its current position and orientation forwarded to control unit for calibration. Compared to other techniques, test results show significant reduction in procedure complexity and calibration time. These improvements enable more frequent TCP checking and recalibration during production, thus improving the product quality.

  7. Absolute wavelength calibration of a Doppler spectrometer with a custom Fabry-Perot optical system

    Science.gov (United States)

    Baltzer, M. M.; Craig, D.; Den Hartog, D. J.; Nishizawa, T.; Nornberg, M. D.

    2016-11-01

    An Ion Doppler Spectrometer (IDS) is used for fast measurements of C VI line emission (343.4 nm) in the Madison Symmetric Torus. Absolutely calibrated flow measurements are difficult because the IDS records data within 0.25 nm of the line. Commercial calibration lamps do not produce lines in this narrow range. A light source using an ultraviolet LED and etalon was designed to provide a fiducial marker 0.08 nm wide. The light is coupled into the IDS at f/4, and a holographic diffuser increases homogeneity of the final image. Random and systematic errors in data analysis were assessed. The calibration is accurate to 0.003 nm, allowing for flow measurements accurate to 3 km/s. This calibration is superior to the previous method which used a time-averaged measurement along a chord believed to have zero net Doppler shift.

  8. Towards monolithic scintillator based TOF-PET systems: practical methods for detector calibration and operation

    Science.gov (United States)

    Borghi, Giacomo; Tabacchini, Valerio; Schaart, Dennis R.

    2016-07-01

    Gamma-ray detectors based on thick monolithic scintillator crystals can achieve spatial resolutions  published k-NN 1D method. Also, the procedures for estimating the DOI and time of interaction are revised to enable full detector calibration by means of fan-beam or flood irradiations only. Moreover, a new technique is presented to allow the use of events in which some of the photosensor pixel values and/or timestamps are missing (e.g. due to dead time), so as to further increase system sensitivity. The accelerated methods were tested on a monolithic scintillator detector specifically developed for clinical PET applications, consisting of a 32 mm  ×  32 mm  ×  22 mm LYSO : Ce crystal coupled to a digital photon counter (DPC) array. This resulted in a spatial resolution of 1.7 mm FWHM, an average DOI resolution of 3.7 mm FWHM, and a CRT of 214 ps. Moreover, the possibility of using events missing the information of up to 16 out of 64 photosensor pixels is shown. This results in only a small deterioration of the detector performance.

  9. Accounting for sensor calibration, data validation, measurement and sampling uncertainties in monitoring urban drainage systems.

    Science.gov (United States)

    Bertrand-Krajewski, J L; Bardin, J P; Mourad, M; Béranger, Y

    2003-01-01

    Assessing the functioning and the performance of urban drainage systems on both rainfall event and yearly time scales is usually based on online measurements of flow rates and on samples of influent effluent for some rainfall events per year. In order to draw pertinent scientific and operational conclusions from the measurement results, it is absolutely necessary to use appropriate methods and techniques in order to i) calibrate sensors and analytical methods, ii) validate raw data, iii) evaluate measurement uncertainties, iv) evaluate the number of rainfall events to sample per year in order to determine performance indicator with a given uncertainty. Based an previous work, the paper gives a synthetic review of required and techniques, and illustrates their application to storage and settling tanks. Experiments show that, controlled and careful experimental conditions, relative uncertainties are about 20% for flow rates in sewer pipes, 6-10% for volumes, 25-35% for TSS concentrations and loads, and 18-276% for TSS removal rates. In order to evaluate the annual pollutant interception efficiency of storage and settling tanks with a given uncertainty, efforts should first be devoted to decrease the sampling uncertainty by increasing the number of sampled events.

  10. Modelling, verification, and calibration of a photoacoustics based continuous non-invasive blood glucose monitoring system.

    Science.gov (United States)

    Pai, Praful P; Sanki, Pradyut K; Sarangi, Satyabrata; Banerjee, Swapna

    2015-06-01

    This paper examines the use of photoacoustic spectroscopy (PAS) at an excitation wavelength of 905 nm for making continuous non-invasive blood glucose measurements. The theoretical background of the measurement technique is verified through simulation. An apparatus is fabricated for performing photoacoustic measurements in vitro on glucose solutions and in vivo on human subjects. The amplitude of the photoacoustic signals measured from glucose solutions is observed to increase with the solution concentration, while photoacoustic amplitude obtained from in vivo measurements follows the blood glucose concentration of the subjects, indicating a direct proportionality between the two quantities. A linear calibration method is applied separately on measurements obtained from each individual in order to estimate the blood glucose concentration. The estimated glucose values are compared to reference glucose concentrations measured using a standard glucose meter. A plot of 196 measurement pairs taken over 30 normal subjects on a Clarke error grid gives a point distribution of 82.65% and 17.35% over zones A and B of the grid with a mean absolute relative deviation (MARD) of 11.78% and a mean absolute difference (MAD) of 15.27 mg/dl (0.85 mmol/l). The results obtained are better than or comparable to those obtained using photoacoustic spectroscopy based methods or other non-invasive measurement techniques available. The accuracy levels obtained are also comparable to commercially available continuous glucose monitoring systems.

  11. LED based calibration systems of the Baikal-GVD neutrino telescope

    Directory of Open Access Journals (Sweden)

    Avrorin A.D.

    2016-01-01

    Full Text Available Baikal-GVD is a cubic-kilometer scale neutrino telescope, which is currently under construction in Lake Baikal. GVD will consist of an array of optical modules arranged in clusters of strings. The first GVD-cluster has been deployed and put in operation in April 2015. We describe equipment and methods for the calibration of the first GVD-cluster and discuss the accuracy of the calibration procedures.

  12. A pipette-based calibration system for fast-scan cyclic voltammetry with fast response times.

    Science.gov (United States)

    Ramsson, Eric S

    2016-01-01

    Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique that utilizes the oxidation and/or reduction of an analyte of interest to infer rapid changes in concentrations. In order to calibrate the resulting oxidative or reductive current, known concentrations of an analyte must be introduced under controlled settings. Here, I describe a simple and cost-effective method, using a Petri dish and pipettes, for the calibration of carbon fiber microelectrodes (CFMs) using FSCV.

  13. Calibration uncertainty

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Anglov, Thomas

    2002-01-01

    Methods recommended by the International Standardization Organisation and Eurachem are not satisfactory for the correct estimation of calibration uncertainty. A novel approach is introduced and tested on actual calibration data for the determination of Pb by ICP-AES. The improved calibration unce...

  14. Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

    Directory of Open Access Journals (Sweden)

    P. Veres

    2010-06-01

    Full Text Available We report on the development of an accurate, portable, dynamic calibration system for volatile organic compounds (VOCs. The Mobile Organic Carbon Calibration System (MOCCS combines the production of gas-phase VOC standards using permeation or diffusion sources with quantitative total organic carbon (TOC conversion on a palladium surface to CO2 in the presence of oxygen, and the subsequent CO2 measurement. MOCCS was validated using three different comparisons: (1 TOC of high accuracy methane standards compared well to expected concentrations (3% relative error, (2 a gas-phase benzene standard was generated using a permeation source and measured by TOC and gas chromatography mass spectrometry (GC-MS with excellent agreement (<4% relative difference, and (3 total carbon measurement of 4 known gas phase mixtures were performed and compared to a calculated carbon content to agreement within the stated uncertainties of the standards. Measurements from laboratory biomass burning experiments of formic acid by negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS and formaldehyde by proton transfer reaction-mass spectrometry (PTR-MS, both calibrated using MOCCS, were compared to open path Fourier transform infrared spectroscopy (OP-FTIR to validate the MOCCS calibration and were found to compare well (R2 of 0.91 and 0.99, respectively.

  15. Development and validation of a portable gas phase standard generation and calibration system for volatile organic compounds

    Directory of Open Access Journals (Sweden)

    P. Veres

    2010-01-01

    Full Text Available We report on the development of an accurate, portable, dynamic calibration system for volatile organic compounds (VOCs. The Mobile Organic Carbon Calibration System (MOCCS combines the production of gas-phase VOC standards using permeation or diffusion sources with quantitative total organic carbon (TOC conversion on a palladium surface to CO2 in the presence of oxygen, and the subsequent CO2 measurement. MOCCS was validated using three different comparisons: (1 TOC of high accuracy methane standards compared well to expected concentrations (3% relative error, (2 a gas-phase benzene standard was generated using a permeation source and measured by TOC and gas chromatography mass spectrometry (GC-MS with excellent agreement (<4% relative difference, and (3 total carbon measurement of 4 known gas phase mixtures were performed and compared to a calculated carbon content to agreement within the stated uncertainties of the standards. Measurements from laboratory biomass burning experiments of formic acid by negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS and formaldehyde by proton transfer reaction-mass spectrometry (PTR-MS, both calibrated using MOCCS, were compared to open path Fourier transform infrared spectroscopy (OP-FTIR to validate the MOCCS calibration and were found to compare well (R2 of 0.91 and 0.99 respectively.

  16. Automatic In Situ Calibration of a Spinning Beam LiDAR System in Static and Kinematic Modes

    Directory of Open Access Journals (Sweden)

    Ting On Chan

    2015-08-01

    Full Text Available The Velodyne LiDAR series is one of the most popular spinning beam LiDAR systems currently available on the market. In this paper, the temporal stability of the range measurements of the Velodyne HDL-32E LiDAR system is first investigated as motivation for the development of a new automatic calibration method that allows quick and frequent recovery of the inherent time-varying errors. The basic principle of the method is that the LiDAR’s internal systematic error parameters are estimated by constraining point clouds of some known and automatically detected cylindrical features such as lamp poles to fit to the 3D cylinder models. This is analogous to the plumb-line calibration method in which the lens distortion parameters are estimated by constraining the image points of straight lines to fit to the 2D line model. The calibration can be performed at every measurement epoch in both static and kinematic modes. Four real datasets were used to verify the method, two of which were captured in static mode and the other two in kinematic mode. The overall results indicate that up to approximately 72% and 41% accuracy improvement were realized as a result of the calibration for the static and kinematic datasets, respectively.

  17. Presentation, calibration and validation of the low-order, DCESS Earth System Model (Version 1

    Directory of Open Access Journals (Sweden)

    J. O. Pepke Pedersen

    2008-11-01

    Full Text Available A new, low-order Earth System Model is described, calibrated and tested against Earth system data. The model features modules for the atmosphere, ocean, ocean sediment, land biosphere and lithosphere and has been designed to simulate global change on time scales of years to millions of years. The atmosphere module considers radiation balance, meridional transport of heat and water vapor between low-mid latitude and high latitude zones, heat and gas exchange with the ocean and sea ice and snow cover. Gases considered are carbon dioxide and methane for all three carbon isotopes, nitrous oxide and oxygen. The ocean module has 100 m vertical resolution, carbonate chemistry and prescribed circulation and mixing. Ocean biogeochemical tracers are phosphate, dissolved oxygen, dissolved inorganic carbon for all three carbon isotopes and alkalinity. Biogenic production of particulate organic matter in the ocean surface layer depends on phosphate availability but with lower efficiency in the high latitude zone, as determined by model fit to ocean data. The calcite to organic carbon rain ratio depends on surface layer temperature. The semi-analytical, ocean sediment module considers calcium carbonate dissolution and oxic and anoxic organic matter remineralisation. The sediment is composed of calcite, non-calcite mineral and reactive organic matter. Sediment porosity profiles are related to sediment composition and a bioturbated layer of 0.1 m thickness is assumed. A sediment segment is ascribed to each ocean layer and segment area stems from observed ocean depth distributions. Sediment burial is calculated from sedimentation velocities at the base of the bioturbated layer. Bioturbation rates and oxic and anoxic remineralisation rates depend on organic carbon rain rates and dissolved oxygen concentrations. The land biosphere module considers leaves, wood, litter and soil. Net primary production depends on atmospheric carbon dioxide concentration and

  18. Presentation, calibration and validation of the low-order, DCESS Earth System Model

    Directory of Open Access Journals (Sweden)

    J. O. P. Pedersen

    2008-06-01

    Full Text Available A new, low-order Earth system model is described, calibrated and tested against Earth system data. The model features modules for the atmosphere, ocean, ocean sediment, land biosphere and lithosphere and has been designed to simulate global change on time scales of years to millions of years. The atmosphere module considers radiation balance, meridional transport of heat and water vapor between low-mid latitude and high latitude zones, heat and gas exchange with the ocean and sea ice and snow cover. Gases considered are carbon dioxide and methane for all three carbon isotopes, nitrous oxide and oxygen. The ocean module has 100 m vertical resolution, carbonate chemistry and prescribed circulation and mixing. Ocean biogeochemical tracers are phosphate, dissolved oxygen, dissolved inorganic carbon for all three carbon isotopes and alkalinity. Biogenic production of particulate organic matter in the ocean surface layer depends on phosphate availability but with lower efficiency in the high latitude zone, as determined by model fit to ocean data. The calcite to organic carbon rain ratio depends on surface layer temperature. The semi-analytical, ocean sediment module considers calcium carbonate dissolution and oxic and anoxic organic matter remineralisation. The sediment is composed of calcite, non-calcite mineral and reactive organic matter. Sediment porosity profiles are related to sediment composition and a bioturbated layer of 0.1 m thickness is assumed. A sediment segment is ascribed to each ocean layer and segment area stems from observed ocean depth distributions. Sediment burial is calculated from sedimentation velocities at the base of the bioturbated layer. Bioturbation rates and oxic and anoxic remineralisation rates depend on organic carbon rain rates and dissolved oxygen concentrations. The land biosphere module considers leaves, wood, litter and soil. Net primary production depends on atmospheric carbon dioxide concentration and

  19. A quasi-online distributed data processing on WAN: the ATLAS muon calibration system

    CERN Document Server

    De Salvo, A; The ATLAS collaboration

    2013-01-01

    In the Atlas experiment, the calibration of the precision tracking chambers of the muon detector is very demanding, since the rate of muon tracks required to get a complete calibration in homogeneous conditions and to feed prompt reconstruction with fresh constants is very high (several hundreds Hz for 8-10 hours runs). The calculation of calibration constants is highly CPU consuming. In order to fulfill the requirement of completing the cycle and having the final constants available within 24 hours, distributed resources at Tier-2 centers have been allocated. The best place to get muon tracks suitable for detector calibration is the second level trigger, where the pre-selection of data sitting in a limited region by the first level trigger via the Region of Interest mechanism allows selecting all the hits from a single track in a limited region of the detector. Online data extraction allows calibration data collection without performing special runs. Small event pseudo-fragments (about 0.5 kB) built at the m...

  20. Improved volumetric imaging in tomosynthesis using combined multiaxial sweeps.

    Science.gov (United States)

    Gersh, Jacob A; Wiant, David B; Best, Ryan C M; Bennett, Marcus C; Munley, Michael T; King, June D; McKee, Mahta M; Baydush, Alan H

    2010-09-03

    This study explores the volumetric reconstruction fidelity attainable using tomosynthesis with a kV imaging system which has a unique ability to rotate isocentrically and with multiple degrees of mechanical freedom. More specifically, we seek to investigate volumetric reconstructions by combining multiple limited-angle rotational image acquisition sweeps. By comparing these reconstructed images with those of a CBCT reconstruction, we can gauge the volumetric fidelity of the reconstructions. In surgical situations, the described tomosynthesis-based system could provide high-quality volumetric imaging without requiring patient motion, even with rotational limitations present. Projections were acquired using the Digital Integrated Brachytherapy Unit, or IBU-D. A phantom was used which contained several spherical objects of varying contrast. Using image projections acquired during isocentric sweeps around the phantom, reconstructions were performed by filtered backprojection. For each image acquisition sweep configuration, a contrasting sphere is analyzed using two metrics and compared to a gold standard CBCT reconstruction. Since the intersection of a reconstructed sphere and an imaging plane is ideally a circle with an eccentricity of zero, the first metric presented compares the effective eccentricity of intersections of reconstructed volumes and imaging planes. As another metric of volumetric reconstruction fidelity, the volume of one of the contrasting spheres was determined using manual contouring. By comparing these manually delineated volumes with a CBCT reconstruction, we can gauge the volumetric fidelity of reconstructions. The configuration which yielded the highest overall volumetric reconstruction fidelity, as determined by effective eccentricities and volumetric contouring, consisted of two orthogonally-offset 60° L-arm sweeps and a single C-arm sweep which shared a pivot point with one the L-arm sweeps. When compared to a similar configuration that

  1. A High Precision Approach to Calibrate a Structured Light Vision Sensor in a Robot-Based Three-Dimensional Measurement System

    Directory of Open Access Journals (Sweden)

    Defeng Wu

    2016-08-01

    Full Text Available A robot-based three-dimensional (3D measurement system is presented. In the presented system, a structured light vision sensor is mounted on the arm of an industrial robot. Measurement accuracy is one of the most important aspects of any 3D measurement system. To improve the measuring accuracy of the structured light vision sensor, a novel sensor calibration approach is proposed to improve the calibration accuracy. The approach is based on a number of fixed concentric circles manufactured in a calibration target. The concentric circle is employed to determine the real projected centres of the circles. Then, a calibration point generation procedure is used with the help of the calibrated robot. When enough calibration points are ready, the radial alignment constraint (RAC method is adopted to calibrate the camera model. A multilayer perceptron neural network (MLPNN is then employed to identify the calibration residuals after the application of the RAC method. Therefore, the hybrid pinhole model and the MLPNN are used to represent the real camera model. Using a standard ball to validate the effectiveness of the presented technique, the experimental results demonstrate that the proposed novel calibration approach can achieve a highly accurate model of the structured light vision sensor.

  2. A High Precision Approach to Calibrate a Structured Light Vision Sensor in a Robot-Based Three-Dimensional Measurement System.

    Science.gov (United States)

    Wu, Defeng; Chen, Tianfei; Li, Aiguo

    2016-08-30

    A robot-based three-dimensional (3D) measurement system is presented. In the presented system, a structured light vision sensor is mounted on the arm of an industrial robot. Measurement accuracy is one of the most important aspects of any 3D measurement system. To improve the measuring accuracy of the structured light vision sensor, a novel sensor calibration approach is proposed to improve the calibration accuracy. The approach is based on a number of fixed concentric circles manufactured in a calibration target. The concentric circle is employed to determine the real projected centres of the circles. Then, a calibration point generation procedure is used with the help of the calibrated robot. When enough calibration points are ready, the radial alignment constraint (RAC) method is adopted to calibrate the camera model. A multilayer perceptron neural network (MLPNN) is then employed to identify the calibration residuals after the application of the RAC method. Therefore, the hybrid pinhole model and the MLPNN are used to represent the real camera model. Using a standard ball to validate the effectiveness of the presented technique, the experimental results demonstrate that the proposed novel calibration approach can achieve a highly accurate model of the structured light vision sensor.

  3. Automatic exposure control calibration and optimisation for abdomen, pelvis and lumbar spine imaging with an Agfa computed radiography system

    Science.gov (United States)

    Moore, C. S.; Wood, T. J.; Avery, G.; Balcam, S.; Needler, L.; Joshi, H.; Saunderson, J. R.; Beavis, A. W.

    2016-11-01

    The use of three physical image quality metrics, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm) have recently been examined by our group for their appropriateness in the calibration of an automatic exposure control (AEC) device for chest radiography with an Agfa computed radiography (CR) imaging system. This study uses the same methodology but investigates AEC calibration for abdomen, pelvis and spine CR imaging. AEC calibration curves were derived using a simple uniform phantom (equivalent to 20 cm water) to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated abdomen, pelvis and spine images (created from real patient CT datasets) with appropriate detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated images contained clinically realistic projected anatomy and were scored by experienced image evaluators. Constant DDI and CNR curves did not provide optimized performance but constant eNEQm and SNR did, with the latter being the preferred calibration metric given that it is easier to measure in practice. This result was consistent with the previous investigation for chest imaging with AEC devices. Medical physicists may therefore use a simple and easily accessible uniform water equivalent phantom to measure the SNR image quality metric described here when calibrating AEC devices for abdomen, pelvis and spine imaging with Agfa CR systems, in the confidence that clinical image quality will be sufficient for the required clinical task. However, to ensure appropriate levels of detector air kerma the advice of expert image evaluators must be sought.

  4. Automatic exposure control calibration and optimisation for abdomen, pelvis and lumbar spine imaging with an Agfa computed radiography system.

    Science.gov (United States)

    Moore, C S; Wood, T J; Avery, G; Balcam, S; Needler, L; Joshi, H; Saunderson, J R; Beavis, A W

    2016-11-07

    The use of three physical image quality metrics, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and mean effective noise equivalent quanta (eNEQm) have recently been examined by our group for their appropriateness in the calibration of an automatic exposure control (AEC) device for chest radiography with an Agfa computed radiography (CR) imaging system. This study uses the same methodology but investigates AEC calibration for abdomen, pelvis and spine CR imaging. AEC calibration curves were derived using a simple uniform phantom (equivalent to 20 cm water) to ensure each metric was held constant across the tube voltage range. Each curve was assessed for its clinical appropriateness by generating computer simulated abdomen, pelvis and spine images (created from real patient CT datasets) with appropriate detector air kermas for each tube voltage, and grading these against reference images which were reconstructed at detector air kermas correct for the constant detector dose indicator (DDI) curve currently programmed into the AEC device. All simulated images contained clinically realistic projected anatomy and were scored by experienced image evaluators. Constant DDI and CNR curves did not provide optimized performance but constant eNEQm and SNR did, with the latter being the preferred calibration metric given that it is easier to measure in practice. This result was consistent with the previous investigation for chest imaging with AEC devices. Medical physicists may therefore use a simple and easily accessible uniform water equivalent phantom to measure the SNR image quality metric described here when calibrating AEC devices for abdomen, pelvis and spine imaging with Agfa CR systems, in the confidence that clinical image quality will be sufficient for the required clinical task. However, to ensure appropriate levels of detector air kerma the advice of expert image evaluators must be sought.

  5. Vicarious Radiometric Calibration of a Multispectral Camera on Board an Unmanned Aerial System

    Directory of Open Access Journals (Sweden)

    Susana Del Pozo

    2014-02-01

    Full Text Available Combinations of unmanned aerial platforms and multispectral sensors are considered low-cost tools for detailed spatial and temporal studies addressing spectral signatures, opening a broad range of applications in remote sensing. Thus, a key step in this process is knowledge of multi-spectral sensor calibration parameters in order to identify the physical variables collected by the sensor. This paper discusses the radiometric calibration process by means of a vicarious method applied to a high-spatial resolution unmanned flight using low-cost artificial and natural covers as control and check surfaces, respectively.

  6. A simple method for calibration of Lucas scintillation cell counting system for measurement of 226Ra and 222Rn

    Directory of Open Access Journals (Sweden)

    N.K. Sethy

    2014-10-01

    Full Text Available Known quantity of radium from high grade ore solution was chemically separated and carefully kept inside the cavity of a Lucas Cell (LC. The 222Rn gradually builds up and attain secular equilibrium with its parent 226Ra. This gives a steady count after a suitable buildup period (>25 days. This secondary source was used to calibrate the radon counting system. The method is validated in by comparison with identical measurement with AlphaGuard Aquakit. The radon counting system was used to evaluate dissolved radon in ground water sample by gross alpha counting in LC. Radon counting system measures the collected radon after a delay of >180 min by gross alpha counting. Simultaneous measurement also carried out by AlphaGuard Aquakit in identical condition. AlphaGuard measures dissolved radon from water sample by constant aeration in a closed circuit without giving any delay. Both the methods are matching with a correlation coefficient of >0.9. This validates the calibration of Lucas scintillation cell counting system by designed encapsulated source. This study provides an alternative for calibration in absence of costly Radon source available in the market.

  7. Volumetric measurements of a spatially growing dust acoustic wave

    Science.gov (United States)

    Williams, Jeremiah D.

    2012-11-01

    In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

  8. Volumetric measurements of a spatially growing dust acoustic wave

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Jeremiah D. [Physics Department, Wittenberg University, Springfield, Ohio 45504 (United States)

    2012-11-15

    In this study, tomographic particle image velocimetry (tomo-PIV) techniques are used to make volumetric measurements of the dust acoustic wave (DAW) in a weakly coupled dusty plasma system in an argon, dc glow discharge plasma. These tomo-PIV measurements provide the first instantaneous volumetric measurement of a naturally occurring propagating DAW. These measurements reveal over the measured volume that the measured wave mode propagates in all three spatial dimensional and exhibits the same spatial growth rate and wavelength in each spatial direction.

  9. Automated Calibration System for a High-Precision Measurement of Neutrino Mixing Angle $\\theta_{13}$ with the Daya Bay Antineutrino Detectors

    CERN Document Server

    Liu, J; Carr, R; Dwyer, D A; Gu, W Q; Li, G S; Qian, X; McKeown, R D; Tsang, R H M; Wang, W; Wu, F F; Zhang, C

    2013-01-01

    We describe the automated calibration system for the antineutrino detectors in the Daya Bay Neutrino Experiment. This system consists of 24 identical units instrumented on 8 identical 20-ton liquid scintillator detectors. Each unit is a fully automated robotic system capable of deploying an LED and various radioactive sources into the detector along given vertical axes. Selected results from performance studies of the calibration system are reported.

  10. Automated calibration system for a high-precision measurement of neutrino mixing angle θ{sub 13} with the Daya Bay antineutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J., E-mail: jianglai.liu@sjtu.edu.cn [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Cai, B.; Carr, R. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Dwyer, D.A. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Gu, W.Q.; Li, G.S. [Department of Physics, Shanghai Jiao Tong University, Shanghai (China); Qian, X. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Brookhaven National Laboratory, Upton, NY (United States); McKeown, R.D. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Department of Physics, College of William and Mary, Williamsburg, VA (United States); Tsang, R.H.M. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Wang, W. [Department of Physics, College of William and Mary, Williamsburg, VA (United States); Wu, F.F. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Zhang, C. [Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States); Brookhaven National Laboratory, Upton, NY (United States)

    2014-06-01

    We describe the automated calibration system for the antineutrino detectors in the Daya Bay Neutrino Experiment. This system consists of 24 identical units instrumented on 8 identical 20-ton liquid scintillator detectors. Each unit is a fully automated robotic system capable of deploying an LED and various radioactive sources into the detector along given vertical axes. Selected results from performance studies of the calibration system are reported.

  11. Photogrammetric calibration of a C-arm X-ray system as a verification tool for orthopaedic navigation systems

    Science.gov (United States)

    Broers, H.; Hemken, H.; Luhmann, T.; Ritschl, P.

    For the total replacement of the knee joint, the precise reconstruction of the mechanical axis is significantly determined by the alignment of the cutting tool with respect to the rotation centre of the femur head. Operation techniques supported by navigation allow for the precise three-dimensional location of the hip centre by cinematic analysis. Recent results permit the reconstruction of the femur axis to be better than 0.7°. Therefore, conventional verification methods such as the post-operative recording of the complete leg are not suitable due to their limited system accuracy of about 2°. As the femur head cannot be accessed directly during the operation, an X-ray method has been used to verify alignment. The paper presents a method and the results achieved for the calibration of a C-arm system by introducing photogrammetric parameters. Since the method is used during operation, boundary conditions such as minimal invasive surgical intervention and sterility have been considered for practical applications of patients.

  12. The INES System; 2, Ripple Correction and Absolute Calibration for IUE High Resolution Spectra

    CERN Document Server

    Cassatella, A; González-Riestra, R; Ponz, J D; Barbero, J F G; Talavera, A; Wamsteker, W

    1999-01-01

    In this paper we document the results of the study which led to the ripple correction and absolute calibration algorithms applied to the high resolution spectra processed with the NEWSIPS software for the Final Archive of the IUE Project. In this analysis, based on a very large number of spectra, we find that both K and the alpha parameters (not only the former as previously believed) vary with order number. This fact, together with the finding that the central peaks of the blaze function vary also as a function of the THDA temperature (for the SWP camera) and of the date of observations (for the LWP and LWR cameras), makes the ripple correction algorithm more complex than previously considered but, at the same time, considerably more reliable. As for the high resolution absolute calibration, the method followed is similar to the one implemented in IUESIPS. The internal accuracy of the high resolution calibration is about 4%. We note that the ripple correction and absolute calibration algorithms here describe...

  13. Non-Metric CCD Camera Calibration Algorithm in a Digital Photogrammetry System

    Institute of Scientific and Technical Information of China (English)

    YANG Hua-chao; DENG Ka-zhong; ZHANG Shu-bi; GUO Guang-li; ZHOU Ming

    2006-01-01

    Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation (DLT) and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectively, which can meet the requirements of close-range photogrammetry with high accuracy.

  14. Near-infrared calibration systems for precise radial-velocity measurements

    Science.gov (United States)

    Redman, Stephen L.; Kerber, Florian; Nave, Gillian; Mahadevan, Suvrath; Ramsey, Lawrence W.; Smoker, Jonathan; Käufl, Hans-Ulrich; Figueira, P. R. L.

    2012-09-01

    We present work done to prepare two new near-infrared calibration sources for use on high-precision astrophysical spectrographs. Uranium-neon is an atomic calibration source, commercially available as a hollow-cathode lamp, with over 10 000 known emission lines between 0.85 and 4 μm. Four gas cells — containing C2H2, H13CN, 12CO, and 13CO, respectively—are available as National Institute of Standards and Technology (nist) Standard Reference Materials (SRMs), and provide narrow absorption lines between 1.5 and 1.65 μm. These calibration sources may prove useful for wavelength-calibrating the future near-infrared high-precision radial-velocity spectrometers, including the Calar Alto high-Resolution search for M dwarfs with Exo-earths with a Near-infrared Echelle Spectrograph (CARMENES),1 the SpectroPolarimetre InfraROUge (SPIRou)∗, and the Habitable-Zone Planet Finder (HPF).2

  15. Power-Budget Equations and Calibration Factors for Fish Abundance Estimation Using Scientific Echo Sounder and Sonar Systems

    Directory of Open Access Journals (Sweden)

    Per Lunde

    2016-07-01

    Full Text Available Acoustic methods used in fish abundance estimation constitute a key part of the analytic assessment that makes the basis for abundance estimation of marine resources. The methods rely on power-budget equations and calibrated systems. Different formulations of power-budget equations and calibration factors have been proposed for use in scientific echo sounder and sonar systems. There are unresolved questions and apparent inconsistencies in prior literature related to this field. A generic (instrument independent and unifying theory is presented that attempts to explain the different power-budget and calibration factor formulations proposed and used in prior literature, and how these are mutually related. Deviations and apparent inconsistencies in this literature appear to be explained and corrected. This also includes different (instrument specific formulations employed in important modern scientific echo sounder systems, and their relationship to the generic theory of abundance estimation. Prior literature is extended to provide more complete power-budget equations for fish abundance estimation and species identification, by accounting for echo integration, electrical termination, and the full range of electrical and acoustical echo sounder parameters. The expressions provide a consistent theoretical basis for improved understanding of conventional methods and instruments used today, also enabling improved sensitivity and error analyses, and correction possibilities.

  16. The Calibration and error analysis of Shallow water (less than 100m) Multibeam Echo-Sounding System

    Science.gov (United States)

    Lin, M.

    2016-12-01

    Multibeam echo-sounders(MBES) have been developed to gather bathymetric and acoustic data for more efficient and more exact mapping of the oceans. This gain in efficiency does not come without drawbacks. Indeed, the finer the resolution of remote sensing instruments, the harder they are to calibrate. This is the case for multibeam echo-sounding systems (MBES). We are no longer dealing with sounding lines where the bathymetry must be interpolated between them to engender consistent representations of the seafloor. We now need to match together strips (swaths) of totally ensonified seabed. As a consequence, misalignment and time lag problems emerge as artifacts in the bathymetry from adjacent or overlapping swaths, particularly when operating in shallow water. More importantly, one must still verify that bathymetric data meet the accuracy requirements. This paper aims to summarize the system integration involved with MBES and identify the various source of error pertaining to shallow water survey (100m and less). A systematic method for the calibration of shallow water MBES is proposed and presented as a set of field procedures. The procedures aim at detecting, quantifying and correcting systematic instrumental and installation errors. Hence, calibrating for variations of the speed of sound in the water column, which is natural in origin, is not addressed in this document. The data which used in calibration will reference International Hydrographic Organization(IHO) and other related standards to compare. This paper aims to set a model in the specific area which can calibrate the error due to instruments. We will construct a procedure in patch test and figure out all the possibilities may make sounding data with error then calculate the error value to compensate. In general, the problems which have to be solved is the patch test's 4 correction in the Hypack system 1.Roll 2.GPS Latency 3.Pitch 4.Yaw. Cause These 4 correction affect each others, we run each survey line

  17. Self-Calibration Approach for Mixed Signal Circuits in Systems-on-Chip

    Science.gov (United States)

    Jung, In-Seok

    MOSFET scaling has served industry very well for a few decades by proving improvements in transistor performance, power, and cost. However, they require high test complexity and cost due to several issues such as limited pin count and integration of analog and digital mixed circuits. Therefore, self-calibration is an excellent and promising method to improve yield and to reduce manufacturing cost by simplifying the test complexity, because it is possible to address the process variation effects by means of self-calibration technique. Since the prior published calibration techniques were developed for a specific targeted application, it is not easy to be utilized for other applications. In order to solve the aforementioned issues, in this dissertation, several novel self-calibration design techniques in mixed-signal mode circuits are proposed for an analog to digital converter (ADC) to reduce mismatch error and improve performance. These are essential components in SOCs and the proposed self-calibration approach also compensates the process variations. The proposed novel self-calibration approach targets the successive approximation (SA) ADC. First of all, the offset error of the comparator in the SA-ADC is reduced using the proposed approach by enabling the capacitor array in the input nodes for better matching. In addition, the auxiliary capacitors for each capacitor of DAC in the SA-ADC are controlled by using synthesized digital controller to minimize the mismatch error of the DAC. Since the proposed technique is applied during foreground operation, the power overhead in SA-ADC case is minimal because the calibration circuit is deactivated during normal operation time. Another benefit of the proposed technique is that the offset voltage of the comparator is continuously adjusted for every step to decide one-bit code, because not only the inherit offset voltage of the comparator but also the mismatch of DAC are compensated simultaneously. Synthesized digital

  18. In-situ calibration of nonuniformity in infrared staring and modulated systems

    Science.gov (United States)

    Black, Wiley T.

    Infrared cameras can directly measure the apparent temperature of objects, providing thermal imaging. However, the raw output from most infrared cameras suffers from a strong, often limiting noise source called nonuniformity. Manufacturing imperfections in infrared focal planes lead to high pixel-to-pixel sensitivity to electronic bias, focal plane temperature, and other effects. The resulting imagery can only provide useful thermal imaging after a nonuniformity calibration has been performed. Traditionally, these calibrations are performed by momentarily blocking the field of view with a at temperature plate or blackbody cavity. However because the pattern is a coupling of manufactured sensitivities with operational variations, periodic recalibration is required, sometimes on the order of tens of seconds. A class of computational methods called Scene-Based Nonuniformity Correction (SBNUC) has been researched for over 20 years where the nonuniformity calibration is estimated in digital processing by analysis of the video stream in the presence of camera motion. The most sophisticated SBNUC methods can completely and robustly eliminate the high-spatial frequency component of nonuniformity with only an initial reference calibration or potentially no physical calibration. I will demonstrate a novel algorithm that advances these SBNUC techniques to support all spatial frequencies of nonuniformity correction. Long-wave infrared microgrid polarimeters are a class of camera that incorporate a microscale per-pixel wire-grid polarizer directly affixed to each pixel of the focal plane. These cameras have the capability of simultaneously measuring thermal imagery and polarization in a robust integrated package with no moving parts. I will describe the necessary adaptations of my SBNUC method to operate on this class of sensor as well as demonstrate SBNUC performance in LWIR polarimetry video collected on the UA mall.

  19. In Vivo Real Time Volumetric Synthetic Aperture Ultrasound Imaging

    DEFF Research Database (Denmark)

    Bouzari, Hamed; Rasmussen, Morten Fischer; Brandt, Andreas Hjelm;

    2015-01-01

    Synthetic aperture (SA) imaging can be used to achieve real-time volumetric ultrasound imaging using 2-D array transducers. The sensitivity of SA imaging is improved by maximizing the acoustic output, but one must consider the limitations of an ultrasound system, both technical and biological...

  20. Volumetric T-spline Construction Using Boolean Operations

    Science.gov (United States)

    2013-07-01

    15213, USA 2 Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, TX 78712, USA 3 Department of Civil and...and S. Yau. Volumetric harmonic map. Communications in Information and Systems, 3(3):191–202, 2003. 12. C.A.R. Guerra . Simultaneous untangling and

  1. Video-rate volumetric optical coherence tomography-based microangiography

    Science.gov (United States)

    Baran, Utku; Wei, Wei; Xu, Jingjiang; Qi, Xiaoli; Davis, Wyatt O.; Wang, Ruikang K.

    2016-04-01

    Video-rate volumetric optical coherence tomography (vOCT) is relatively young in the field of OCT imaging but has great potential in biomedical applications. Due to the recent development of the MHz range swept laser sources, vOCT has started to gain attention in the community. Here, we report the first in vivo video-rate volumetric OCT-based microangiography (vOMAG) system by integrating an 18-kHz resonant microelectromechanical system (MEMS) mirror with a 1.6-MHz FDML swept source operating at ˜1.3 μm wavelength. Because the MEMS scanner can offer an effective B-frame rate of 36 kHz, we are able to engineer vOMAG with a video rate up to 25 Hz. This system was utilized for real-time volumetric in vivo visualization of cerebral microvasculature in mice. Moreover, we monitored the blood perfusion dynamics during stimulation within mouse ear in vivo. We also discussed this system's limitations. Prospective MEMS-enabled OCT probes with a real-time volumetric functional imaging capability can have a significant impact on endoscopic imaging and image-guided surgery applications.

  2. Construction and calibration of the laser alignment system for the CMS tracker

    Energy Technology Data Exchange (ETDEWEB)

    Adolphi, R.

    2006-11-28

    A robust and reliable optical system able to measure and control the large CMS tracker geometry with high accuracy has been developed and validated. The construction and integration of the LAS fulfilling the requirements, as well as its calibration and performance are described in this thesis. The working principle is based on the partial transparency of silicon for light wavelengths in the near infrared region. The absorbed part of the laser beam generates a signal in the corresponding silicon strip module serving to reconstruct its position. The transmitted part reaches the subsequent module layer generating an optical link between the two layers. Investigation of the light generation and distribution led to a definition of the optical components and their optimization for Laser Alignment purposes. Laser diodes have been qualified as light sources and singlemode optical fibres, terminated by special connectors, distribute the light to the CMS tracker detector. The beamsplitting device, a key component of the LAS light distribution inside the CMS tracker, has been studied in detail. The challenge of splitting one collimated beam into two back-to-back beams inside a small available volume has been solved by using the polarization principle. Special test setups were developed to determine the collinearity of the two outgoing beams with a precision better than 50 {mu}rad and it has been shown that their relative orientation remains constant under working conditions. The interface between the tracker and the LAS is given by the silicon sensors which are responsible both for particle detection and for the determination of the position of the laser spot. An anti-reflex-coating has been applied on the backside of all alignment sensors to improve their optical properties without deterioration of their tracking performance. A test setup has been developed to simultaneously study the transmission and reflection properties of the alignment sensors. The working principle of

  3. Comparison of the performance between portal dosimetry and a commercial two-dimensional array system on pretreatment quality assurance for volumetric-modulated arc and intensity-modulated radiation therapy

    Science.gov (United States)

    Kim, Yon-Lae; Chung, Jin-Beom; Kim, Jae-Sung; Lee, Jeong-Woo; Choi, Kyoung-Sik

    2014-04-01

    The aim of this study was to compare the dosimetric performance and to evaluate the pretreatment quality assurance (QA) of a portal dosimetry and a commercial two-dimensional (2-D) array system. In the characteristics comparison study, the measured values for the dose linearity, dose rate response, reproducibility, and field size dependence for 6-MV photon beams were analyzed for both detector systems. To perform the qualitative evaluations of the 10 IMRT and the 10 VMAT plans, we used the Gamma index for quantifying the agreement between calculations and measurements. The performance estimates for both systems show that overall, minimal differences in the dosimetric characteristics exist between the Electron portal imaging device (EPID) and 2-D array system. In the qualitative analysis for pretreatment quality assurance, the EPID and 2-D array system yield similar passing rate results for the majority of clinical Intensity-modulated radiation therapy (IMRT) and Volumetric-modulated arc therapy (VMAT) cases. These results were satisfactory for IMRT and VMAT fields and were within the acceptable criteria of γ%≤1, γ avg <0.5. The EPDI and the 2-D array systems showed comparable dosimetric results. In this study, the results revealed both systems to be suitable for patient-specific QA measurements for IMRT and VMAT. We conclude that, depending on the status of clinic, both systems can be used interchangeably for routine pretreatment QA.

  4. A quasi-rigorous model based on improved ICP algorithm in the application of auto-calibration of airborne LiDAR system

    Science.gov (United States)

    Li, Lelin; Jiang, San

    2015-12-01

    The purpose of the airborne LiDAR system calibration is to eliminate the influence of system error and improve the precision of the original point cloud data. In certain hypothesis of flight conditions, the directly positioning model for LiDAR can be reduced to a quasi-rigorous model, and the dependence on the original observation data for the system calibration model is reduced too. In view of the shortcoming of human interaction way to establish corresponding relationship between strips, an improved ICP method which considering the object features in point clouds is proposed to get the transform relationship between strips, and the automatic calibration procedures of LiDAR system is established in this paper. Taking with the real LiDAR data in Baotou test field, experiment results show that the proposed system calibration procedures can greatly eliminate the influence of system error.

  5. Metrological tests of a 200 L calibration source for HPGE detector systems for assay of radioactive waste drums.

    Science.gov (United States)

    Boshkova, T; Mitev, K

    2016-03-01

    In this work we present test procedures, approval criteria and results from two metrological inspections of a certified large volume (152)Eu source (drum about 200L) intended for calibration of HPGe gamma assay systems used for activity measurement of radioactive waste drums. The aim of the inspections was to prove the stability of the calibration source during its working life. The large volume source was designed and produced in 2007. It consists of 448 identical sealed radioactive sources (modules) apportioned in 32 transparent plastic tubes which were placed in a wooden matrix which filled the drum. During the inspections the modules were subjected to tests for verification of their certified characteristics. The results show a perfect compliance with the NIST basic guidelines for the properties of a radioactive certified reference material (CRM) and demonstrate the stability of the large volume CRM-drum after 7 years of operation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. The fixed-bias Langmuir probe on the Communication/Navigation Outage Forecast System satellite: calibration and validation.

    Science.gov (United States)

    Klenzing, J; Rowland, D

    2012-11-01

    A fixed-bias spherical Langmuir probe is included as part of the Vector Electric Field Instrument (VEFI) suite on the Communication/Navigation Outage Forecast System (C/NOFS) satellite. C/NOFS gathers data in the equatorial ionosphere between 400 and 860 km, where the primary constituent ions are H(+) and O(+). The ion current collected by the probe surface per unit plasma density is found to be a strong function of ion composition. The calibration of the collected current to an absolute density is discussed, and the performance of the spherical probe is compared to other in situ instruments on board the C/NOFS satellite. The application of the calibration is discussed with respect to future fixed-bias probes; in particular, it is demonstrated that some density fluctuations will be suppressed in the collected current if the plasma composition rapidly changes along with density. This is illustrated in the observation of plasma density enhancements on C/NOFS.

  7. The Fixed-Bias Langmuir Probe on the Communication-Navigation Outage Forecast System Satellite: Calibration and Validation

    Science.gov (United States)

    Klenzing, J.; Rowland, D.

    2012-01-01

    A fixed-bias spherical Langmuir probe is included as part of the Vector Electric Field Instrument (VEFI) suite on the Communication Navigation Outage Forecast System (CNOFS) satellite.CNOFS gathers data in the equatorial ionosphere between 400 and 860 km, where the primary constituent ions are H+ and O+. The ion current collected by the probe surface per unit plasma density is found to be a strong function of ion composition. The calibration of the collected current to an absolute density is discussed, and the performance of the spherical probe is compared to other in situ instruments on board the CNOFS satellite. The application of the calibration is discussed with respect to future fixed-bias probes; in particular, it is demonstrated that some density fluctuations will be suppressed in the collected current if the plasma composition rapidly changes along with density. This is illustrated in the observation of plasma density enhancements on CNOFS.

  8. 压力仪表校验系统设计研究%Pressure gauge calibration system design research

    Institute of Scientific and Technical Information of China (English)

    刘玺

    2012-01-01

    首先介绍了当前行业内压力表校验系统的研究现状,并分析了当前压力仪表检定的发展方向,最后重点对压力仪表校验系统设计,从系统的需求分析出发进行了分析和研究.%This paper firstly introduces the current status of industry within pressure gauge calibration system application, through literature methodology, and analyzed the current pressure gauge verification research situation and developing direction. The research content is discussed on the basis of research of main purpose and topic research. With related system design theory of pressure gauge calibration system design, from the system of needs analysis, this paper summarized the system based on the basic function requirement. Through system design, this paper expounds the basic theory of system design should meet the basic principles.

  9. NASA Glenn Icing Research Tunnel: Upgrade and Cloud Calibration

    Science.gov (United States)

    VanZante, Judith Foss; Ide, Robert F.; Steen, Laura E.

    2012-01-01

    In 2011, NASA Glenn s Icing Research Tunnel underwent a major modification to it s refrigeration plant and heat exchanger. This paper presents the results of the subsequent full cloud calibration. Details of the calibration procedure and results are presented herein. The steps include developing a nozzle transfer map, establishing a uniform cloud, conducting a drop sizing calibration and finally a liquid water content calibration. The goal of the calibration is to develop a uniform cloud, and to build a transfer map from the inputs of air speed, spray bar atomizing air pressure and water pressure to the output of median volumetric droplet diameter and liquid water content.

  10. A High Precision Approach to Calibrate a Structured Light Vision Sensor in a Robot-Based Three-Dimensional Measurement System

    OpenAIRE

    2016-01-01

    A robot-based three-dimensional (3D) measurement system is presented. In the presented system, a structured light vision sensor is mounted on the arm of an industrial robot. Measurement accuracy is one of the most important aspects of any 3D measurement system. To improve the measuring accuracy of the structured light vision sensor, a novel sensor calibration approach is proposed to improve the calibration accuracy. The approach is based on a number of fixed concentric circles manufactured in...

  11. Best practices in passive remote sensing VNIR hyperspectral system hardware calibrations

    Science.gov (United States)

    Jablonski, Joseph; Durell, Christopher; Slonecker, Terrence; Wong, Kwok; Simon, Blair; Eichelberger, Andrew; Osterberg, Jacob

    2016-05-01

    Hyperspectral imaging (HSI) is an exciting and rapidly expanding area of instruments and technology in passive remote sensing. Due to quickly changing applications, the instruments are evolving to suit new uses and there is a need for consistent definition, testing, characterization and calibration. This paper seeks to outline a broad prescription and recommendations for basic specification, testing and characterization that must be done on Visible Near Infra-Red grating-based sensors in order to provide calibrated absolute output and performance or at least relative performance that will suit the user's task. The primary goal of this paper is to provide awareness of the issues with performance of this technology and make recommendations towards standards and protocols that could be used for further efforts in emerging procedures for national laboratory and standards groups.

  12. Best practices in passive remote sensing VNIR hyperspectral system hardware calibrations

    Science.gov (United States)

    Jablonski, Joseph; Durell, Christopher; Slonecker, Terry; Wong, Kwok; Simon, Blair; Eichelberger, Andrew; Osterberg, Jacob

    2016-01-01

    Hyperspectral imaging (HSI) is an exciting and rapidly expanding area of instruments and technology in passive remote sensing. Due to quickly changing applications, the instruments are evolving to suit new uses and there is a need for consistent definition, testing, characterization and calibration. This paper seeks to outline a broad prescription and recommendations for basic specification, testing and characterization that must be done on Visible Near Infra-Red grating-based sensors in order to provide calibrated absolute output and performance or at least relative performance that will suit the user’s task. The primary goal of this paper is to provide awareness of the issues with performance of this technology and make recommendations towards standards and protocols that could be used for further efforts in emerging procedures for national laboratory and standards groups.

  13. Absolute-magnitude Calibration for W UMa-type Systems Based on Gaia Data

    Science.gov (United States)

    Mateo, Nicole M.; Rucinski, Slavek M.

    2017-09-01

    Tycho-Gaia Astrometric Solution (TGAS) parallax data are used to determine absolute magnitudes M V for 318 W UMa-type (EW) contact binary stars. A very steep (slope ≃ ‑9), single-parameter ({log}P), linear calibration can be used to predict M V to about 0.1–0.3 mag over the whole range of accessible orbital period, 0.22distribution. Although the scatter around the linear {log}P-fit is fairly large (0.2–0.4 mag), the current data do not support the inclusion of a B-V color term in the calibration. ). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement.

  14. RSA calibration accuracy of a fluoroscopy-based system using nonorthogonal images for measuring functional kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Kedgley, Angela E.; Jenkyn, Thomas R. [Department of Mechanical and Materials Engineering, Faculty of Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada); Wolf Orthopaedic Biomechanics Laboratory, Fowler Kennedy Sport Medicine Clinic, London, Ontario N6A 5B9 (Canada); Department of Mechanical and Materials Engineering, Faculty of Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada) and School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario N6A 5B9 (Canada)

    2009-07-15

    When performing radiostereometric analysis (RSA) in a clinical setting it may be desirable to orient the two imaging devices nonorthogonally to obtain the best views of an anatomical structure. In this study, a calibration frame was constructed that allowed the relative angles of fiducial and control planes to be adjusted. Precision and accuracy were quantified across multiple trials and orientations. The 90 deg. frame was always of equivalent or greater accuracy than a calibration frame with the fiducial and control planes aligned parallel to the image intensifiers. This study also showed that RSA may be performed with imaging devices at relative angles other than 90 deg. without compromising accuracy. This allows researchers greater freedom in positioning equipment.

  15. QconCAT standard for calibration of ion mobility-mass spectrometry systems.

    Science.gov (United States)

    Chawner, Ross; McCullough, Bryan; Giles, Kevin; Barran, Perdita E; Gaskell, Simon J; Eyers, Claire E

    2012-11-01

    Ion mobility-mass spectrometry (IM-MS) is a useful technique for determining information about analyte ion conformation in addition to mass/charge ratio. The physical principles that govern the mobility of an ion through a gas in the presence of a uniform electric field are well understood, enabling rotationally averaged collision cross sections (Ω) to be directly calculated from measured drift times under well-defined experimental conditions. However, such "first principle" calculations are not straightforward for Traveling Wave (T-Wave) mobility separations due to the range of factors that influence ion motion through the mobility cell. If collision cross section information is required from T-Wave mobility separations, then calibration of the instruments using known standards is essential for each set of experimental conditions. To facilitate such calibration, we have designed and generated an artificial protein based on the QconCAT technology, QCAL-IM, which upon proteolysis can be used as a universal ion mobility calibration standard. This single unique standard enables empirical calculation of peptide ion collision cross sections from the drift time on a T-Wave mobility instrument.

  16. Measurements of b-hadron lifetimes and the calibration and performance of the LHCb tracking system

    CERN Document Server

    Dupertuis, Frédéric Guillaume

    The LHCb experiment was designed to perform high precision measurements. The LHCb detector has excellent vertexing, momentum measurement and particle identification capabilities, with a detector geometry and trigger strategy specially adapted for the study of rare decays and $CP$ violation of $b$- and $c$-quarks. For accurate measurements, the detector needs to be perfectly calibrated and its performance monitored to achieve the required performance. The LHCb TELL1 boards are responsible for the acquisition and the pre-processing of the raw data. New effects on signals emitted by the front-end chip, the Beetle, of the Inner Tracker (IT) and Tracker Turicensis (TT) due to the different header configurations are discovered. Strategies to correct for these her effects are proposed and are implemented in the firmware of the IT and TT TELL1 boards. In addition, faster algorithms are developed to perform the calibration of the TELL1 boards and software is developed to perform the full calibration and a monitoring ...

  17. Performance evaluation for full three-dimensional projector calibration methods in spatial augmented reality

    Science.gov (United States)

    Korostelev, Michael

    Spatial Augment Reality (SAR) has presented itself to be an interesting tool for not only interesting ways to visualize information but to develop creative works in performance arts. The main challenge is to determine accurate geometry of a projection space and determine an efficient and effective way to project digital media and information to create an augmented space. In our previous implementation of SAR, we developed a projector-camera calibration approach using infrared markers. However, the projection suffers severe distortion due to the lack of depth information in the projection space. For this research, we propose to develop a RGBD sensor - projector system to replace our current projector-camera SAR system. Proper calibration between the camera or sensor and projector links vision to projection, answering the question of which point in camera space maps to what point in the space of projection. Calibration will resolve the problem of capturing the geometry of the space and allow us to accurately augment the surfaces of volumetric objects and features. In this work three calibration methods are examined for performance and accuracy. Two of these methods are existing adaptations of 2D camera - projector calibrations (calibration using arbitrary planes and ray-plane intersection) with our third proposed novel technique which utilizes point cloud information from the RGBD sensor directly. Through analysis and evaluation using re-projection error, results are presented, identifying the proposed method as practical and robust.

  18. Efficiency calibration and minimum detectable activity concentration of a real-time UAV airborne sensor system with two gamma spectrometers.

    Science.gov (United States)

    Tang, Xiao-Bin; Meng, Jia; Wang, Peng; Cao, Ye; Huang, Xi; Wen, Liang-Sheng; Chen, Da

    2016-04-01

    A small-sized UAV (NH-UAV) airborne system with two gamma spectrometers (LaBr3 detector and HPGe detector) was developed to monitor activity concentration in serious nuclear accidents, such as the Fukushima nuclear accident. The efficiency calibration and determination of minimum detectable activity concentration (MDAC) of the specific system were studied by MC simulations at different flight altitudes, different horizontal distances from the detection position to the source term center and different source term sizes. Both air and ground radiation were considered in the models. The results obtained may provide instructive suggestions for in-situ radioactivity measurements of NH-UAV.

  19. Air Data Calibration Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This facility is for low altitude subsonic altimeter system calibrations of air vehicles. Mission is a direct support of the AFFTC mission. Postflight data merge is...

  20. SPOTS Calibration Example

    Directory of Open Access Journals (Sweden)

    Patterson E.

    2010-06-01

    Full Text Available The results are presented using the procedure outlined by the Standardisation Project for Optical Techniques of Strain measurement to calibrate a digital image correlation system. The process involves comparing the experimental data obtained with the optical measurement system to the theoretical values for a specially designed specimen. The standard states the criteria which must be met in order to achieve successful calibration, in addition to quantifying the measurement uncertainty in the system. The system was evaluated at three different displacement load levels, generating strain ranges from 289 µstrain to 2110 µstrain. At the 289 µstrain range, the calibration uncertainty was found to be 14.1 µstrain, and at the 2110 µstrain range it was found to be 28.9 µstrain. This calibration procedure was performed without painting a speckle pattern on the surface of the metal. Instead, the specimen surface was prepared using different grades of grit paper to produce the desired texture.