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Sample records for 3d computed tomographic

  1. Mobile 3D tomograph

    Mobile tomographs often have the problem that high spatial resolution is impossible owing to the position or setup of the tomograph. While the tree tomograph developed by Messrs. Isotopenforschung Dr. Sauerwein GmbH worked well in practice, it is no longer used as the spatial resolution and measuring time are insufficient for many modern applications. The paper shows that the mechanical base of the method is sufficient for 3D CT measurements with modern detectors and X-ray tubes. CT measurements with very good statistics take less than 10 min. This means that mobile systems can be used, e.g. in examinations of non-transportable cultural objects or monuments. Enhancement of the spatial resolution of mobile tomographs capable of measuring in any position is made difficult by the fact that the tomograph has moving parts and will therefore have weight shifts. With the aid of tomographies whose spatial resolution is far higher than the mechanical accuracy, a correction method is presented for direct integration of the Feldkamp algorithm

  2. Measurement of facial soft tissues thickness using 3D computed tomographic images

    To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side. The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. There were no statistically significant differences between the direct measurements and those using the 3D images(p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissue thickness more easily in forensic science and anthropology

  3. Computed 3D visualisation of an extinct cephalopod using computer tomographs

    Lukeneder, Alexander

    2012-01-01

    The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of t...

  4. Computed 3D visualisation of an extinct cephalopod using computer tomographs.

    Lukeneder, Alexander

    2012-08-01

    The first 3D visualisation of a heteromorph cephalopod species from the Southern Alps (Dolomites, northern Italy) is presented. Computed tomography, palaeontological data and 3D reconstructions were included in the production of a movie, which shows a life reconstruction of the extinct organism. This detailed reconstruction is according to the current knowledge of the shape and mode of life as well as habitat of this animal. The results are based on the most complete shell known thus far of the genus Dissimilites. Object-based combined analyses from computed tomography and various computed 3D facility programmes help to understand morphological details as well as their ontogentical changes in fossil material. In this study, an additional goal was to show changes in locomotion during different ontogenetic phases of such fossil, marine shell-bearing animals (ammonoids). Hence, the presented models and tools can serve as starting points for discussions on morphology and locomotion of extinct cephalopods in general, and of the genus Dissimilites in particular. The heteromorph ammonoid genus Dissimilites is interpreted here as an active swimmer of the Tethyan Ocean. This study portrays non-destructive methods of 3D visualisation applied on palaeontological material, starting with computed tomography resulting in animated, high-quality video clips. The here presented 3D geometrical models and animation, which are based on palaeontological material, demonstrate the wide range of applications, analytical techniques and also outline possible limitations of 3D models in earth sciences and palaeontology. The realistic 3D models and motion pictures can easily be shared amongst palaeontologists. Data, images and short clips can be discussed online and, if necessary, adapted in morphological details and motion-style to better represent the cephalopod animal. PMID:24850976

  5. 3D Reconstruction Technique for Tomographic PIV

    姜楠; 包全; 杨绍琼

    2015-01-01

    Tomographic particle image velocimetry(Tomo-PIV) is a state-of-the-art experimental technique based on a method of optical tomography to achieve the three-dimensional(3D) reconstruction for three-dimensional three-component(3D-3C) flow velocity measurements. 3D reconstruction for Tomo-PIV is carried out herein. Meanwhile, a 3D simplified tomographic reconstruction model reduced from a 3D volume light inten-sity field with 2D projection images into a 2D Tomo-slice plane with 1D projecting lines, i.e., simplifying this 3D reconstruction into a problem of 2D Tomo-slice plane reconstruction, is applied thereafter. Two kinds of the most well-known algebraic reconstruction techniques, algebraic reconstruction technique(ART) and multiple algebraic reconstruction technique(MART), are compared as well. The principles of the two reconstruction algorithms are discussed in detail, which has been performed by a series of simulation images, yielding the corresponding recon-struction images that show different features between the ART and MART algorithm, and then their advantages and disadvantages are discussed. Further discussions are made for the standard particle image reconstruction when the background noise of the pre-initial particle image has been removed. Results show that the particle image recon-struction has been greatly improved. The MART algorithm is much better than the ART. Furthermore, the computa-tional analyses of two parameters(the particle density and the number of cameras), are performed to study their effects on the reconstruction. Lastly, the 3D volume particle field is reconstructed by using the improved algorithm based on the simplified 3D tomographic reconstruction model, which proves that the algorithm simplification is feasible and it can be applied to the reconstruction of 3D volume particle field in a Tomo-PIV system.

  6. Mapping Faults from 3-D Tomographic Velocity Model using Image Processing / Computer Vision Algorithms: Application to Northern Cascadia

    Ramachandran, K.

    2011-12-01

    Three dimensional velocity models constructed through seismic tomography are seldom digitally processed further for imaging structural features. A study conducted to evaluate the potential for imaging subsurface discontinuities in horizontal and vertical direction from three dimensional velocity models using image processing/computer vision techniques has provided significant results. Three-dimensional velocity models constructed through tomographic inversion of active source and/or earthquake traveltime data are generally built from an initial 1-D velocity model that varies only with depth. Regularized tomographic inversion algorithms impose constraints on the roughness of the model that help to stabilize the inversion process. Final velocity models obtained from regularized tomographic inversions have smooth three-dimensional structures that are required by the data. Final velocity models are usually analyzed and interpreted either as a perturbation velocity model or as an absolute velocity model. Compared to perturbation velocity model, absolute velocity model has an advantage of providing constraints on lithology. Both velocity models lack the ability to provide sharp constraints on subsurface faults. However, results from the analysis of the 3-D velocity model from northern Cascadia using Roberts, Prewitt, Sobel, and Canny operators show that subsurface faults that are not clearly interpretable from velocity model plots can be identified through this approach. This analysis resulted in inferring the locations of Tacoma Fault, Seattle Fault, Southern Whidbey Island Fault, and Darrington Devils Mountain fault much clearly. The Coast Range Boundary Fault, previously hypothesized on the basis of sedimentological and tectonic observations is inferred clearly from processed images. Many of the fault locations so imaged correlate with earthquake hypocenters indicating their seismogenic nature.

  7. Association of achondroplasia with Down syndrome: difficulty in prenatal diagnosis by sonographic and 3-D helical computed tomographic analyses.

    Kaga, Akimune; Murotsuki, Jun; Kamimura, Miki; Kimura, Masato; Saito-Hakoda, Akiko; Kanno, Junko; Hoshi, Kazuhiko; Kure, Shigeo; Fujiwara, Ikuma

    2015-05-01

    Achondroplasia and Down syndrome are relatively common conditions individually. But co-occurrence of both conditions in the same patient is rare and there have been no reports of fetal analysis of this condition by prenatal sonographic and three-dimensional (3-D) helical computed tomography (CT). Prenatal sonographic findings seen in persons with Down syndrome, such as a thickened nuchal fold, cardiac defects, and echogenic bowel were not found in the patient. A prenatal 3-D helical CT revealed a large head with frontal bossing, metaphyseal flaring of the long bones, and small iliac wings, which suggested achondroplasia. In a case with combination of achondroplasia and Down syndrome, it may be difficult to diagnose the co-occurrence prenatally without typical markers of Down syndrome. PMID:25385298

  8. Practical pseudo-3D registration for large tomographic images

    Liu, Xuan; Laperre, Kjell; Sasov, Alexander

    2014-09-01

    Image registration is a powerful tool in various tomographic applications. Our main focus is on microCT applications in which samples/animals can be scanned multiple times under different conditions or at different time points. For this purpose, a registration tool capable of handling fairly large volumes has been developed, using a novel pseudo-3D method to achieve fast and interactive registration with simultaneous 3D visualization. To reduce computation complexity in 3D registration, we decompose it into several 2D registrations, which are applied to the orthogonal views (transaxial, sagittal and coronal) sequentially and iteratively. After registration in each view, the next view is retrieved with the new transformation matrix for registration. This reduces the computation complexity significantly. For rigid transform, we only need to search for 3 parameters (2 shifts, 1 rotation) in each of the 3 orthogonal views instead of 6 (3 shifts, 3 rotations) for full 3D volume. In addition, the amount of voxels involved is also significantly reduced. For the proposed pseudo-3D method, image-based registration is employed, with Sum of Square Difference (SSD) as the similarity measure. The searching engine is Powell's conjugate direction method. In this paper, only rigid transform is used. However, it can be extended to affine transform by adding scaling and possibly shearing to the transform model. We have noticed that more information can be used in the 2D registration if Maximum Intensity Projections (MIP) or Parallel Projections (PP) is used instead of the orthogonal views. Also, other similarity measures, such as covariance or mutual information, can be easily incorporated. The initial evaluation on microCT data shows very promising results. Two application examples are shown: dental samples before and after treatment and structural changes in materials before and after compression. Evaluation on registration accuracy between pseudo-3D method and true 3D method has

  9. Development of a tomographic system adapted to 3D measurement of contaminated wounds based on the Cacao concept (Computer aided collimation Gamma Camera)

    The computer aided collimation gamma camera (CACAO in French) is a gamma camera using a collimator with large holes, a supplementary linear scanning motion during the acquisition and a dedicated reconstruction program taking full account of the source depth. The CACAO system was introduced to improve both the sensitivity and the resolution in nuclear medicine. This thesis focuses on the design of a fast and robust reconstruction algorithm in the CACAO project. We start by an overview of tomographic imaging techniques in nuclear medicine. After modelling the physical CACAO system, we present the complete reconstruction program which involves three steps: 1) shift and sum 2) deconvolution and filtering 3) rotation and sum. The deconvolution is the critical step that decreases the signal to noise ratio of the reconstructed images. We propose a regularized multi-channel algorithm to solve the deconvolution problem. We also present a fast algorithm based on Splines functions and preserving the high quality of the reconstructed images for the shift and the rotation steps. Comparisons of simulated reconstructed images in 2D and 3D for the conventional system (CPHC) and CACAO demonstrate the ability of CACAO system to increase the quality of the SPECT images. Finally, this study concludes with an experimental approach with a pixellated detector conceived for a 3D measurement of contaminated wounds. This experimentation proves the possible advantages of coupling the CACAO project with pixellated detectors. Moreover, a variety of applications could fully benefit from the CACAO system, such as low activity imaging, the use of high-energy gamma isotopes and the visualization of deep organs. Moreover the combination of the CACAO system with a pixels detector may open up further possibilities for the future of nuclear medicine. (author)

  10. Performance Analysis of a 3D Ionosphere Tomographic Model

    Liu Zhi-zhao; Gao Yang

    2003-01-01

    A 3D high precision ionospheric model is developed based on tomography technique. This tomographic model employs GPS data observed by an operational network of dual-frequency GPS receivers. The methodology of developing a 3D ionospheric tomography model is briefly summarized. However emphasis is put on the analysis and evaluation of the accuracy variation of 3D ionosphere modeling with respect to the change of GPS data cutoff angle.Three typical cutoff angle values (15°, 20° and 25°) are tested. For each testing cutoff angle, the performances of the3D ionospheric model constructed using tomography technique are assessed by calibrating the model predicted ionospheric TEC with the GPS measured TEC and by employing the model predicted TEC to a practical GPS positioning application single point positioning (SPP).Test results indicate the 3D model predicted VTEC has about 0.4 TECU improvement in accuracy when cutoff angle rises from 15° to 20°. However, no apparent improvement is found from 20° to 25°. The model's improvement is also validated by the better SPP accuracy of 3D model than its counterpart-dual frequency model in the 20° and 25° cases.

  11. The advantage of the three dimensional computed tomographic (3 D-CT for ensuring accurate bone incision in sagittal split ramus osteotomy

    Coen Pramono D

    2005-03-01

    Full Text Available Functional and aesthetic dysgnathia surgery requires accurate pre-surgical planning, including the surgical technique to be used related with the difference of anatomical structures amongst individuals. Programs that simulate the surgery become increasingly important. This can be mediated by using a surgical model, conventional x-rays as panoramic, cephalometric projections and another sophisticated method such as a three dimensional computed tomography (3 D-CT. A patient who had undergone double jaw surgeries with difficult anatomical landmarks was presented. In this case the mandible foramens were seen highly relatively related to the sigmoid notches. Therefore, ensuring the bone incisions in sagittal split was presumed to be difficult. A 3D-CT was made and considered to be very helpful in supporting the pre-operative diagnostic.

  12. Use of transputers in a 3-D positron emission tomograph

    This paper discusses the use of a VME-based transputer system as a front-end parallel processing engine for Positron Volume Imaging. The authors model different topologies with different numbers of nodes, using the Master/Worker software paradigm called a Processor Farm, and determine optimum configuration parameters for different computation requirements. The versatility and scalability of transputers makes them very suitable for use in PVI tomographs in that the same transputers can be used for speeding up data acquisition, image reconstruction and display

  13. Fast 3-d tomographic microwave imaging for breast cancer detection.

    Grzegorczyk, Tomasz M; Meaney, Paul M; Kaufman, Peter A; diFlorio-Alexander, Roberta M; Paulsen, Keith D

    2012-08-01

    Microwave breast imaging (using electromagnetic waves of frequencies around 1 GHz) has mostly remained at the research level for the past decade, gaining little clinical acceptance. The major hurdles limiting patient use are both at the hardware level (challenges in collecting accurate and noncorrupted data) and software level (often plagued by unrealistic reconstruction times in the tens of hours). In this paper we report improvements that address both issues. First, the hardware is able to measure signals down to levels compatible with sub-centimeter image resolution while keeping an exam time under 2 min. Second, the software overcomes the enormous time burden and produces similarly accurate images in less than 20 min. The combination of the new hardware and software allows us to produce and report here the first clinical 3-D microwave tomographic images of the breast. Two clinical examples are selected out of 400+ exams conducted at the Dartmouth Hitchcock Medical Center (Lebanon, NH). The first example demonstrates the potential usefulness of our system for breast cancer screening while the second example focuses on therapy monitoring. PMID:22562726

  14. Implementation of 3D tomographic visualisation through planar ICT data from experimental gamma-ray tomographic system

    Industrial Computed Tomography (ICT) is one of the latest methods of non-destructive testing and examination. Different prototypes of Computed Industrial Tomographic Imaging System (CITIS) have been developed and experimental data have been generated in Isotope Applications Division. The experimental gamma-rays based tomographic imaging system comprises of beam generator containing approx. 220 GBq (6 Curies) of 137Cs, a single NaI(Tl) -PMT integral assembly in a thick shielding and associated electronics, stepper motor controlled mechanical manipulator, collimators and required software. CITIS data is normally acquired in one orientation of the sample. It may be sometimes required to view a tomographic plane in a different orientation. Also, 3D visualization may be required with the available 2D data set. All these can be achieved by processing the available data. We have customized some of the routines for this purpose provided IDL (Integrated Data Language) package to suit our requirements. The present paper discusses methodology adopted for this purpose with an illustrative example. (author)

  15. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    Sommer, C. M., E-mail: christof.sommer@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Fritz, S., E-mail: stefan.fritz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Vollherbst, D., E-mail: dominikvollherbst@web.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Zelzer, S., E-mail: s.zelzer@dkfz-heidelberg.de [German Cancer Research Center (dkfz), Medical and Biological Informatics (Germany); Wachter, M. F., E-mail: fredericwachter@googlemail.com; Bellemann, N., E-mail: nadine.bellemann@med.uni-heidelberg.de; Gockner, T., E-mail: theresa.gockner@med.uni-heidelberg.de; Mokry, T., E-mail: theresa.mokry@med.uni-heidelberg.de; Schmitz, A., E-mail: anne.schmitz@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Aulmann, S., E-mail: sebastian.aulmann@mail.com [University Hospital Heidelberg, Department of General Pathology (Germany); Stampfl, U., E-mail: ulrike.stampfl@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P., E-mail: philippe.pereira@slk-kliniken.de [SLK Kliniken Heilbronn GmbH, Clinic for Radiology, Minimally-invasive Therapies and Nuclear Medicine (Germany); Kauczor, H. U., E-mail: hu.kauczor@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany); Werner, J., E-mail: jens.werner@med.uni-heidelberg.de [University Hospital Heidelberg, Department of General Visceral and Transplantation Surgery (Germany); Radeleff, B. A., E-mail: boris.radeleff@med.uni-heidelberg.de [University Hospital Heidelberg, Department of Diagnostic and Interventional Radiology (Germany)

    2015-02-15

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm{sup 3}, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm{sup 3}, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver.

  16. CT-guided Irreversible Electroporation in an Acute Porcine Liver Model: Effect of Previous Transarterial Iodized Oil Tissue Marking on Technical Parameters, 3D Computed Tomographic Rendering of the Electroporation Zone, and Histopathology

    PurposeTo evaluate the effect of previous transarterial iodized oil tissue marking (ITM) on technical parameters, three-dimensional (3D) computed tomographic (CT) rendering of the electroporation zone, and histopathology after CT-guided irreversible electroporation (IRE) in an acute porcine liver model as a potential strategy to improve IRE performance.MethodsAfter Ethics Committee approval was obtained, in five landrace pigs, two IREs of the right and left liver (RL and LL) were performed under CT guidance with identical electroporation parameters. Before IRE, transarterial marking of the LL was performed with iodized oil. Nonenhanced and contrast-enhanced CT examinations followed. One hour after IRE, animals were killed and livers collected. Mean resulting voltage and amperage during IRE were assessed. For 3D CT rendering of the electroporation zone, parameters for size and shape were analyzed. Quantitative data were compared by the Mann–Whitney test. Histopathological differences were assessed.ResultsMean resulting voltage and amperage were 2,545.3 ± 66.0 V and 26.1 ± 1.8 A for RL, and 2,537.3 ± 69.0 V and 27.7 ± 1.8 A for LL without significant differences. Short axis, volume, and sphericity index were 16.5 ± 4.4 mm, 8.6 ± 3.2 cm3, and 1.7 ± 0.3 for RL, and 18.2 ± 3.4 mm, 9.8 ± 3.8 cm3, and 1.7 ± 0.3 for LL without significant differences. For RL and LL, the electroporation zone consisted of severely widened hepatic sinusoids containing erythrocytes and showed homogeneous apoptosis. For LL, iodized oil could be detected in the center and at the rim of the electroporation zone.ConclusionThere is no adverse effect of previous ITM on technical parameters, 3D CT rendering of the electroporation zone, and histopathology after CT-guided IRE of the liver

  17. 3D Computations and Experiments

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2004-04-05

    This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.

  18. 3D flame topography obtained by tomographic chemiluminescence with direct comparison to planar Mie scattering measurements.

    Xu, Wenjiang; Wickersham, A J; Wu, Yue; He, Fan; Ma, Lin

    2015-03-20

    This work reports the measurements of 3D flame topography using tomographic chemiluminescence and its validation by direct comparison against planar Mie scattering measurements. Tomographic measurements of the 3D topography of various well-controlled laboratory flames were performed using projections measured by seven cameras, and a simultaneous Mie scattering measurement was performed to measure a 2D cross section of the 3D flame topography. The tomographic measurements were based on chemiluminescence emissions from the flame, and the Mie scattering measurements were based on micrometer-size oil droplets seeded into the flow. The flame topography derived from the 3D tomographic and the Mie scattering measurement was then directly compared. The results show that the flame topography obtained from tomographic chemiluminescence and the Mie measurement agreed qualitatively (i.e., both methods yielded the same profile of the flame fronts), but a quantitative difference on the order of millimeters was observed between these two methods. These results are expected to be useful for understanding the capabilities and limitations of the 3D tomographic and Mie scattering techniques in combustion diagnostics. PMID:25968497

  19. Computer tomographic findings in neurosyphilis

    Pavithran K

    1993-01-01

    Computer tomographic features of the brain in 2 cases of neurosyphilis are described. Less prominence of the cortical sulci suggesting cortical atrophy was the predominant feature in a case of general paralysis of insane. Diffuse, irregular, non-enhancing, low-attenuated area in the cortical and subcortical region of the right temporoparietal lobe of a patient with vascular syphilis, suggested infarction of the brain.

  20. Computer tomographic findings in neurosyphilis

    Pavithran K

    1993-01-01

    Full Text Available Computer tomographic features of the brain in 2 cases of neurosyphilis are described. Less prominence of the cortical sulci suggesting cortical atrophy was the predominant feature in a case of general paralysis of insane. Diffuse, irregular, non-enhancing, low-attenuated area in the cortical and subcortical region of the right temporoparietal lobe of a patient with vascular syphilis, suggested infarction of the brain.

  1. 3D electrical tomographic imaging using vertical arrays of electrodes

    Murphy, S. C.; Stanley, S. J.; Rhodes, D.; York, T. A.

    2006-11-01

    Linear arrays of electrodes in conjunction with electrical impedance tomography have been used to spatially interrogate industrial processes that have only limited access for sensor placement. This paper explores the compromises that are to be expected when using a small number of vertically positioned linear arrays to facilitate 3D imaging using electrical tomography. A configuration with three arrays is found to give reasonable results when compared with a 'conventional' arrangement of circumferential electrodes. A single array yields highly localized sensitivity that struggles to image the whole space. Strategies have been tested on a small-scale version of a sludge settling application that is of relevance to the industrial sponsor. A new electrode excitation strategy, referred to here as 'planar cross drive', is found to give superior results to an extended version of the adjacent electrodes technique due to the improved uniformity of the sensitivity across the domain. Recommendations are suggested for parameters to inform the scale-up to industrial vessels.

  2. Tomographic 3D-radiometry for the visualisation and measurement of the defects of girth seams

    Tomographic Computer Aided Radiology (TomoCAR) is based on the mechanical position control of an X-ray tube in front of a weld seam and the application of a Dgital Detector Array (DDA) behind it. Several hundred radiometric projections in small angle steps are acquired. The tomographical reconstruction allows the three-dimensional (3D) representation of the defects. A new radiometric detector array with small internal unsharpness and high image contrast was used for the 2- and 3-dimensional visualization and sizing of planar defects with a defect opening of less than 100 μm. This detector is based on a CMOS-flat panel with a direct converting CdTe-single crystal layer. The small design allows the application of the mobile testing equipment for mechanized X-ray inspection in industrial plants. The physical pixel size of the detector amounts to 0,1 x 0,1 mm2. Nevertheless, this system yields a better spatial resolution than indirect converting detectors (e.g. cameras with fluorescence layers of Gd2O2S). It allows the reliable detection of planar defects with openings far below the detector pixel size by subpixel resolution. A German pilot study was successfully carried out on the basis of the ENIQ guidelines. In this context 'TomoCAR' was qualified for application in the nuclear power industry. (orig.)

  3. Post-processing methods of rendering and visualizing 3-D reconstructed tomographic images

    The purpose of this presentation is to discuss the computer processing techniques of tomographic images, after they have been generated by imaging scanners, for volume visualization. Volume visualization is concerned with the representation, manipulation, and rendering of volumetric data. Since the first digital images were produced from computed tomography (CT) scanners in the mid 1970s, applications of visualization in medicine have expanded dramatically. Today, three-dimensional (3D) medical visualization has expanded from using CT data, the first inherently digital source of 3D medical data, to using data from various medical imaging modalities, including magnetic resonance scanners, positron emission scanners, digital ultrasound, electronic and confocal microscopy, and other medical imaging modalities. We have advanced from rendering anatomy to aid diagnosis and visualize complex anatomic structures to planning and assisting surgery and radiation treatment. New, more accurate and cost-effective procedures for clinical services and biomedical research have become possible by integrating computer graphics technology with medical images. This trend is particularly noticeable in current market-driven health care environment. For example, interventional imaging, image-guided surgery, and stereotactic and visualization techniques are now stemming into surgical practice. In this presentation, we discuss only computer-display-based approaches of volumetric medical visualization. That is, we assume that the display device available is two-dimensional (2D) in nature and all analysis of multidimensional image data is to be carried out via the 2D screen of the device. There are technologies such as holography and virtual reality that do provide a open-quotes true 3D screenclose quotes. To confine the scope, this presentation will not discuss such approaches

  4. Post-processing methods of rendering and visualizing 3-D reconstructed tomographic images

    Wong, S.T.C. [Univ. of California, San Francisco, CA (United States)

    1997-02-01

    The purpose of this presentation is to discuss the computer processing techniques of tomographic images, after they have been generated by imaging scanners, for volume visualization. Volume visualization is concerned with the representation, manipulation, and rendering of volumetric data. Since the first digital images were produced from computed tomography (CT) scanners in the mid 1970s, applications of visualization in medicine have expanded dramatically. Today, three-dimensional (3D) medical visualization has expanded from using CT data, the first inherently digital source of 3D medical data, to using data from various medical imaging modalities, including magnetic resonance scanners, positron emission scanners, digital ultrasound, electronic and confocal microscopy, and other medical imaging modalities. We have advanced from rendering anatomy to aid diagnosis and visualize complex anatomic structures to planning and assisting surgery and radiation treatment. New, more accurate and cost-effective procedures for clinical services and biomedical research have become possible by integrating computer graphics technology with medical images. This trend is particularly noticeable in current market-driven health care environment. For example, interventional imaging, image-guided surgery, and stereotactic and visualization techniques are now stemming into surgical practice. In this presentation, we discuss only computer-display-based approaches of volumetric medical visualization. That is, we assume that the display device available is two-dimensional (2D) in nature and all analysis of multidimensional image data is to be carried out via the 2D screen of the device. There are technologies such as holography and virtual reality that do provide a {open_quotes}true 3D screen{close_quotes}. To confine the scope, this presentation will not discuss such approaches.

  5. Parametrizable cameras for 3D computational steering

    Mulder, J.D.; Wijk, J.J. van

    1997-01-01

    We present a method for the definition of multiple views in 3D interfaces for computational steering. The method uses the concept of a point-based parametrizable camera object. This concept enables a user to create and configure multiple views on his custom 3D interface in an intuitive graphical man

  6. 3D velocity measurements in a premixed flame by tomographic PIV

    Tokarev, M. P.; Sharaborin, D. K.; Lobasov, A. S.; Chikishev, L. M.; Dulin, V. M.; Markovich, D. M.

    2015-06-01

    Tomographic particle image velocimetry (PIV) has become a standard tool for 3D velocity measurements in non-reacting flows. However, the majority of the measurements in flows with combustion are limited to small resolved depth compared to the size of the field of view (typically 1 : 10). The limitations are associated with inhomogeneity of the volume illumination and the non-uniform flow seeding, the optical distortions and errors in the 3D calibration, and the unwanted flame luminosity. In the present work, the above constraints were overcome for the tomographic PIV experiment in a laminar axisymmetric premixed flame. The measurements were conducted for a 1 : 1 depth-to-size ratio using a system of eight CCD cameras and a 200 mJ pulsed laser. The results show that camera calibration based on the triangulation of the tracer particles in the non-reacting conditions provided reliable accuracy for the 3D image reconstruction in the flame. The modification of the tomographic reconstruction allowed a posteriori removal of unwanted bright objects, which were located outside of the region of interest but affected the reconstruction quality. This study reports on a novel experience for the instantaneous 3D velocimetry in laboratory-scale flames by using tomographic PIV.

  7. Computationally efficient storage of 3D particle intensity and position data for use in 3D PIV and 3D PTV

    Three-dimensional (3D) volumetric velocity measurement techniques, such as tomographic or holographic particle image velocimetry (PIV), rely upon the computationally intensive formation, storage and localized interrogation of multiple 3D particle intensity fields. Calculation of a single velocity field typically requires the extraction of particle intensities into tens of thousands of 3D sub-volumes or discrete particle clusters, the processing of which can significantly affect the performance of 3D cross-correlation based PIV and 3D particle tracking velocimetry (PTV). In this paper, a series of popular and customized volumetric data formats are presented and investigated using synthetic particle volumes and experimental data arising from tomographic PIV measurements of a turbulent boundary layer. Results show that the use of a sub-grid ordered non-zero intensity format with a sub-grid size of 16 × 16 × 16 points provides the best performance for cross-correlation based PIV analysis, while a particle clustered non-zero intensity format provides the best format for PTV applications. In practical tomographic PIV measurements the sub-grid ordered non-zero intensity format offered a 29% improvement in reconstruction times, while providing a 93% reduction in volume data requirements and a 28% overall improvement in cross-correlation based velocity analysis and validation times. (paper)

  8. Computationally efficient storage of 3D particle intensity and position data for use in 3D PIV and 3D PTV

    Atkinson, C.; Buchmann, N. A.; Soria, J.

    2013-11-01

    Three-dimensional (3D) volumetric velocity measurement techniques, such as tomographic or holographic particle image velocimetry (PIV), rely upon the computationally intensive formation, storage and localized interrogation of multiple 3D particle intensity fields. Calculation of a single velocity field typically requires the extraction of particle intensities into tens of thousands of 3D sub-volumes or discrete particle clusters, the processing of which can significantly affect the performance of 3D cross-correlation based PIV and 3D particle tracking velocimetry (PTV). In this paper, a series of popular and customized volumetric data formats are presented and investigated using synthetic particle volumes and experimental data arising from tomographic PIV measurements of a turbulent boundary layer. Results show that the use of a sub-grid ordered non-zero intensity format with a sub-grid size of 16 × 16 × 16 points provides the best performance for cross-correlation based PIV analysis, while a particle clustered non-zero intensity format provides the best format for PTV applications. In practical tomographic PIV measurements the sub-grid ordered non-zero intensity format offered a 29% improvement in reconstruction times, while providing a 93% reduction in volume data requirements and a 28% overall improvement in cross-correlation based velocity analysis and validation times.

  9. Computer Modelling of 3D Geological Surface

    Kodge, B G

    2011-01-01

    The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.

  10. Computer Modelling of 3D Geological Surface

    Kodge B. G.

    2011-02-01

    Full Text Available The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.

  11. Infra Red 3D Computer Mouse

    Harbo, Anders La-Cour; Stoustrup, Jakob

    2000-01-01

    The infra red 3D mouse is a three dimensional input device to a computer. It works by determining the position of an arbitrary object (like a hand) by emitting infra red signals from a number of locations and measuring the reflected intensities. To maximize stability, robustness, and use of bandw......The infra red 3D mouse is a three dimensional input device to a computer. It works by determining the position of an arbitrary object (like a hand) by emitting infra red signals from a number of locations and measuring the reflected intensities. To maximize stability, robustness, and use...

  12. A 3D tomographic EBSD analysis of a CVD diamond thin film

    Tao Liu, Dierk Raabe and Stefan Zaefferer

    2008-01-01

    Full Text Available We have studied the nucleation and growth processes in a chemical vapor deposition (CVD diamond film using a tomographic electron backscattering diffraction method (3D EBSD. The approach is based on the combination of a focused ion beam (FIB unit for serial sectioning in conjunction with high-resolution EBSD. Individual diamond grains were investigated in 3-dimensions particularly with regard to the role of twinning.

  13. Recovery and Visualization of 3D Structure of Chromosomes from Tomographic Reconstruction Images

    Babu, S; Liao, P; Shin, M C; Tsap, L V

    2004-04-28

    The objectives of this work include automatic recovery and visualization of a 3D chromosome structure from a sequence of 2D tomographic reconstruction images taken through the nucleus of a cell. Structure is very important for biologists as it affects chromosome functions, behavior of the cell and its state. Chromosome analysis is significant in the detection of deceases and in monitoring environmental gene mutations. The algorithm incorporates thresholding based on a histogram analysis with a polyline splitting algorithm, contour extraction via active contours, and detection of the 3D chromosome structure by establishing corresponding regions throughout the slices. Visualization using point cloud meshing generates a 3D surface. The 3D triangular mesh of the chromosomes provides surface detail and allows a user to interactively analyze chromosomes using visualization software.

  14. 3D Cameras: 3D Computer Vision of Wide Scope

    May, Stefan; Pervoelz, Kai; Surmann, Hartmut

    2007-01-01

    First of all, a short comparison of range sensors and their underlying principles was given. The chapter further focused on 3D cameras. The latest innovations have given a significant improvement for the measurement accuracy, wherefore this technology has attracted attention in the robotics community. This was also the motivation for the examination in this chapter. On this account, several applications were presented, which represents common problems in the domain of autonomous robotics. For...

  15. Three-dimensional mapping of soil chemical characteristics at micrometric scale: Statistical prediction by combining 2D SEM-EDX data and 3D X-ray computed micro-tomographic images

    Hapca, Simona

    2015-04-01

    Many soil properties and functions emerge from interactions of physical, chemical and biological processes at microscopic scales, which can be understood only by integrating techniques that traditionally are developed within separate disciplines. While recent advances in imaging techniques, such as X-ray computed tomography (X-ray CT), offer the possibility to reconstruct the 3D physical structure at fine resolutions, for the distribution of chemicals in soil, existing methods, based on scanning electron microscope (SEM) and energy dispersive X-ray detection (EDX), allow for characterization of the chemical composition only on 2D surfaces. At present, direct 3D measurement techniques are still lacking, sequential sectioning of soils, followed by 2D mapping of chemical elements and interpolation to 3D, being an alternative which is explored in this study. Specifically, we develop an integrated experimental and theoretical framework which combines 3D X-ray CT imaging technique with 2D SEM-EDX and use spatial statistics methods to map the chemical composition of soil in 3D. The procedure involves three stages 1) scanning a resin impregnated soil cube by X-ray CT, followed by precision cutting to produce parallel thin slices, the surfaces of which are scanned by SEM-EDX, 2) alignment of the 2D chemical maps within the internal 3D structure of the soil cube, and 3) development, of spatial statistics methods to predict the chemical composition of 3D soil based on the observed 2D chemical and 3D physical data. Specifically, three statistical models consisting of a regression tree, a regression tree kriging and cokriging model were used to predict the 3D spatial distribution of carbon, silicon, iron and oxygen in soil, these chemical elements showing a good spatial agreement between the X-ray grayscale intensities and the corresponding 2D SEM-EDX data. Due to the spatial correlation between the physical and chemical data, the regression-tree model showed a great potential

  16. Simultaneous high-speed 3D flame front detection and tomographic PIV

    Ebi, Dominik; Clemens, Noel T.

    2016-03-01

    A technique capable of detecting the instantaneous, time-resolved, 3D flame topography is successfully demonstrated in a lean-premixed swirl flame undergoing flashback. A simultaneous measurement of the volumetric velocity field is possible without the need for additional hardware. Droplets which vaporize in the preheat zone of the flame serve as the marker for the flame front. The droplets are illuminated with a laser and imaged from four different views followed by a tomographic reconstruction to obtain the volumetric particle field. Void regions in the reconstructed particle field, which correspond to regions of burnt gas, are detected with a series of image processing steps. The interface separating the void region from regions filled with particles is defined as the flame surface. The velocity field in the unburnt gas is measured using tomographic PIV. The resulting data include the simultaneous 3D flame front and 3D volumetric velocity field at 5 kHz. The technique is applied to a lean-premixed (ϕ  =  0.8), swirling methane-air flame and validated against simultaneously acquired planar measurements. The mean error associated with the reconstructed 3D flame topography is about 0.4 mm, which is smaller than the flame thickness under the studied conditions. The mean error associated with the volumetric velocity field is about 0.2 m s-1.

  17. Deformable 3D-2D registration for CT and its application to low dose tomographic fluoroscopy

    Flach, Barbara; Brehm, Marcus; Sawall, Stefan; Kachelrieß, Marc

    2014-12-01

    Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be applied. But research in temporal-correlated image reconstruction and dose reductions increases the number of cases where rawdata are available from only few projection angles. Here, deteriorated image quality leads to non-acceptable deformable volume-to-volume registration results. Therefore a registration approach is required that is robust against a decreasing number of projections defining the target position. We propose a deformable volume-to-rawdata (3D-2D) registration method that aims at finding a displacement vector field maximizing the alignment of a CT volume and the acquired rawdata based on the sum of squared differences in rawdata domain. The registration is constrained by a regularization term in accordance with a fluid-based diffusion. Both cost function components, the rawdata fidelity and the regularization term, are optimized in an alternating manner. The matching criterion is optimized by a conjugate gradient descent for nonlinear functions, while the regularization is realized by convolution of the vector fields with Gaussian kernels. We validate the proposed method and compare it to the demons algorithm, a well-known 3D-3D registration method. The comparison is done for a range of 4-60 target projections using datasets from low dose tomographic fluoroscopy as an application example. The results show a high correlation to the ground truth target position without introducing artifacts even in the case of very few projections. In particular the matching in the rawdata domain is improved compared to the 3D-3D registration for the investigated range. The proposed volume-to-rawdata registration increases the robustness regarding sparse

  18. A 3-D tomographic trajectory retrieval for the air-borne limb-imager GLORIA

    J. Ungermann

    2011-06-01

    Full Text Available Infrared limb sounding from aircraft can provide 2-D curtains of multiple trace gas species. However, conventional limb sounders view perpendicular to the aircraft axis and are unable to resolve the observed airmass along their line-of-sight. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere is a new remote sensing instrument able to adjust its horizontal view angle with respect to the aircraft flight direction from 45° to 135°. This will allow for tomographic measurements of mesoscale structures for a wide variety of atmospheric constituents.

    Many flights of the GLORIA instrument will not follow closed curves that allow measuring an airmass from all directions. Consequently, it is examined by means of simulations, what results can be expected from tomographic evaluation of measurements made during a straight flight. It is demonstrated that the achievable resolution and stability is enhanced compared to conventional retrievals. In a second step, it is shown that the incorporation of channels exhibiting different optical depth can greatly enhance the 3-D retrieval quality enabling the exploitation of previously unused spectral samples.

    A second problem for tomographic retrievals is that advection, which can be neglected for conventional retrievals, plays an important role for the time-scales involved in a tomographic measurement flight. This paper presents a method to diagnose the effect of a time-varying atmosphere on a 3-D retrieval and demonstrates an effective way to compensate for effects of advection by incorporating wind-fields from meteorological datasets as a priori information.

  19. 3D tomographic reconstruction of coronary arteries using a precomputed 4D motion field

    In this paper, we present a new method to perform 3D tomographic reconstruction of coronary arteries from cone-beam rotational x-ray angiography acquisitions. We take advantage of the precomputation of the coronary artery motion, modelled as a parametric 4D motion field. Contrary to data gating or data triggering approaches, we homogeneously use all available frames, independently of the cardiac phase. In addition, we artificially subtract angiograms from their background structures. Our method significantly improves the reconstruction, by removing both motion and background artefacts. We have successfully tested it on the datasets from a synthetic phantom and 10 patients

  20. Practical algorithms for 3D computer graphics

    Ferguson, R Stuart

    2013-01-01

    ""A valuable book to accompany any course that mixes the theory and practice of 3D graphics. The book's web site has many useful programs and code samples.""-Karen Rafferty, Queen's University, Belfast""The topics covered by this book are backed by the OpenFX modeling and animation software. This is a big plus in that it provides a practical perspective and encourages experimentation. … [This] will offer students a more interesting and hands-on learning experience, especially for those wishing to pursue a career in computer game development.""-Naganand Madhavapeddy, GameDeveloper>

  1. Estimation of the thermal conductivity of hemp based insulation material from 3D tomographic images

    El-Sawalhi, R.; Lux, J.; Salagnac, P.

    2016-08-01

    In this work, we are interested in the structural and thermal characterization of natural fiber insulation materials. The thermal performance of these materials depends on the arrangement of fibers, which is the consequence of the manufacturing process. In order to optimize these materials, thermal conductivity models can be used to correlate some relevant structural parameters with the effective thermal conductivity. However, only a few models are able to take into account the anisotropy of such material related to the fibers orientation, and these models still need realistic input data (fiber orientation distribution, porosity, etc.). The structural characteristics are here directly measured on a 3D tomographic image using advanced image analysis techniques. Critical structural parameters like porosity, pore and fiber size distribution as well as local fiber orientation distribution are measured. The results of the tested conductivity models are then compared with the conductivity tensor obtained by numerical simulation on the discretized 3D microstructure, as well as available experimental measurements. We show that 1D analytical models are generally not suitable for assessing the thermal conductivity of such anisotropic media. Yet, a few anisotropic models can still be of interest to relate some structural parameters, like the fiber orientation distribution, to the thermal properties. Finally, our results emphasize that numerical simulations on 3D realistic microstructure is a very interesting alternative to experimental measurements.

  2. Clinical Value of 64-slice Three-dimensional Computed Tomographic Angiography to Diagnosis of Intracranial Aneurysms%3D-CTA在颅内动脉瘤诊断中的临床应用价值

    王龙; 陈谦学; 田道锋; 晏炳元; 徐海涛; 吴立权; 陈伟

    2009-01-01

    目的 探讨64排三维CT血管造影(3D-CTA)在以蛛网膜下腔出血(SAH)为主要表现的颅内动脉瘤(ICAs)诊断中的临床应用价值.方法 回顾性分析181例SAH患者资料,其中3D-CTA及DSA影像学资料由一位神经外科医师和-位放射或介入科医师按双肓原则分析.最终以DSA及手术资料对3D-CTA在ICAs诊断中的临床应用价值进行评价.结果 181例SAH患者.3D-CTA共发现143例共166个动脉瘤,DSA及手术证实动脉瘤144例共170个.3D-CTA对SAH患者中动脉瘤的检出率为97.6%,对直径小于2 mm的动脉瘤检出率为66.7%,对直径大于2 mm的动脉瘤检出率接近100%.此外,3D-CTA还可清晰确切显示瘤体、瘤颈、载瘤动脉与周围组织的关系.结论 64排3D-CTA对SAH患者动脉瘤的诊断具有敏感、快捷、无创、经济等优点,与DSA有机结合有助于指导ICAs的诊断及治疗.

  3. GPU-based rapid reconstruction of cellular 3D refractive index maps from tomographic phase microscopy (Conference Presentation)

    Dardikman, Gili; Shaked, Natan T.

    2016-03-01

    We present highly parallel and efficient algorithms for real-time reconstruction of the quantitative three-dimensional (3-D) refractive-index maps of biological cells without labeling, as obtained from the interferometric projections acquired by tomographic phase microscopy (TPM). The new algorithms are implemented on the graphic processing unit (GPU) of the computer using CUDA programming environment. The reconstruction process includes two main parts. First, we used parallel complex wave-front reconstruction of the TPM-based interferometric projections acquired at various angles. The complex wave front reconstructions are done on the GPU in parallel, while minimizing the calculation time of the Fourier transforms and phase unwrapping needed. Next, we implemented on the GPU in parallel the 3-D refractive index map retrieval using the TPM filtered-back projection algorithm. The incorporation of algorithms that are inherently parallel with a programming environment such as Nvidia's CUDA makes it possible to obtain real-time processing rate, and enables high-throughput platform for label-free, 3-D cell visualization and diagnosis.

  4. Computed tomographic imaging of pulmonary alveolar proteinosis

    Pulmonary alveolar proteinosis is a rare disease of uncertain etiology. The computed tomographic image is characterized by geographically sharply delineated alveolar infiltrates, faint, ground-glass-like parenchymal turbidity, with well bordered interstitial structures and recesses in the subpleural space. (orig.)

  5. Computed Tomographic Scan Evaluation of Pulmonary Blastomycosis

    Suzanne Ronald

    2009-01-01

    Full Text Available BACKGROUND: Blastomycosis is an uncommon granulomatous pulmonary and extrapulmonary infectious disease caused by the thermally dimorphic fungus Blastomyces dermatitidis. Diagnosis may be delayed or difficult because of varied presentation. The characteristics of blastomycosis on computed tomographic (CT scan of the chest are not well characterized.

  6. Computed tomographic appearances of sternocostoclavicular hyperostosis

    Chigira, Masaki; Shimizu, Toru (Gunma Univ. (Japan). Dept. of Orthopaedic Surgery)

    1989-08-01

    Computed tomographical analysis of sternocostoclavicular hyperostosis was performed in 27 patients. In the earliest stage hyperostosis occurred around the cartilaginous portion of the first ribs. The sternoclavicular joint space was preserved even in the late stage III of the disorder. It is also suggested that perichondritis and periostitis play important roles in the etiology of this disorder. (orig./GDG).

  7. Computed tomographic findings of benign retroperitoneal tumors

    Matsuura, Takashi; Nakata, Hajime; Nakayama, Chikashi (Univ. of Occupational and Environmental Health School of Medicine, Kitakyushu, Fukuoka (Japan)); Nishitani, Hiroshi; Matsuura, Keiichi

    1983-07-01

    We have reviewed the computed tomographic (CT) findings of 8 cases of benign retroperitoneal tumors with histological proof. Two teratomas, two schwannomas, and one each of epidermoid cyst, simple cyst, bronchogenic cyst, and cystic lymphangioma were included. The most common CT appearance of these tumors was the solitary, round, well-demarcated, relatively low density mass. Capsule or calcification was demonstrated in some. CT is a highly valuable non-invasive examination method for a diagnosis of a benign retroperitoneal tumor.

  8. Infrared tomographic PIV and 3D motion tracking system applied to aquatic predator–prey interaction

    Infrared tomographic PIV and 3D motion tracking are combined to measure evolving volumetric velocity fields and organism trajectories during aquatic predator–prey interactions. The technique was used to study zebrafish foraging on both non-evasive and evasive prey species. Measurement volumes of 22.5 mm × 10.5 mm × 12 mm were reconstructed from images captured on a set of four high-speed cameras. To obtain accurate fluid velocity vectors within each volume, fish were first masked out using an automated visual hull method. Fish and prey locations were identified independently from the same image sets and tracked separately within the measurement volume. Experiments demonstrated that fish were not influenced by the infrared laser illumination or the tracer particles. Results showed that the zebrafish used different strategies, suction and ram feeding, for successful capture of non-evasive and evasive prey, respectively. The two strategies yielded different variations in fluid velocity between the fish mouth and the prey. In general, the results suggest that the local flow field, the direction of prey locomotion with respect to the predator and the relative accelerations and speeds of the predator and prey may all be significant in determining predation success. (paper)

  9. 3D flow visualization and tomographic particle image velocimetry for vortex breakdown over a non-slender delta wing

    Wang, ChengYue; Gao, Qi; Wei, RunJie; Li, Tian; Wang, JinJun

    2016-06-01

    Volumetric measurement for the leading-edge vortex (LEV) breakdown of a delta wing has been conducted by three-dimensional (3D) flow visualization and tomographic particle image velocimetry (TPIV). The 3D flow visualization is employed to show the vortex structures, which was recorded by four cameras with high resolution. 3D dye streaklines of the visualization are reconstructed using a similar way of particle reconstruction in TPIV. Tomographic PIV is carried out at the same time using same cameras with the dye visualization. Q criterion is employed to identify the LEV. Results of tomographic PIV agree well with the reconstructed 3D dye streaklines, which proves the validity of the measurements. The time-averaged flow field based on TPIV is shown and described by sections of velocity and streamwise vorticity. Combining the two measurement methods sheds light on the complex structures of both bubble type and spiral type of breakdown. The breakdown position is recognized by investigating both the streaklines and TPIV velocity fields. Proper orthogonal decomposition is applied to extract a pair of conjugated helical instability modes from TPIV data. Therefore, the dominant frequency of the instability modes is obtained from the corresponding POD coefficients of the modes based on wavelet transform analysis.

  10. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA’s) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 – April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity

  11. Imaging of 3-D seismic velocity structure of Southern Sumatra region using double difference tomographic method

    Lestari, Titik, E-mail: t2klestari@gmail.com [Meteorological Climatological and Geophysical Agency (MCGA), Jalan Angkasa I No.2 Kemayoran, Jakarta Pusat, 10720 (Indonesia); Faculty of Earth Science and Technology, Bandung Institute of Technology, Jalan Ganesa No.10, Bandung 40132 (Indonesia); Nugraha, Andri Dian, E-mail: nugraha@gf.itb.ac.id [Global Geophysical Research Group, Faculty of Mining and Petroleum Engineering, Bandung Institute of Technology, Jalan Ganesa 10 Bandung 40132 (Indonesia)

    2015-04-24

    Southern Sumatra region has a high level of seismicity due to the influence of the subduction system, Sumatra fault, Mentawai fault and stretching zone activities. The seismic activities of Southern Sumatra region are recorded by Meteorological Climatological and Geophysical Agency (MCGA’s) Seismograph network. In this study, we used earthquake data catalog compiled by MCGA for 3013 events from 10 seismic stations around Southern Sumatra region for time periods of April 2009 – April 2014 in order to invert for the 3-D seismic velocities structure (Vp, Vs, and Vp/Vs ratio). We applied double-difference seismic tomography method (tomoDD) to determine Vp, Vs and Vp/Vs ratio with hypocenter adjustment. For the inversion procedure, we started from the initial 1-D seismic velocity model of AK135 and constant Vp/Vs of 1.73. The synthetic travel time from source to receiver was calculated using ray pseudo-bending technique, while the main tomographic inversion was applied using LSQR method. The resolution model was evaluated using checkerboard test and Derivative Weigh Sum (DWS). Our preliminary results show low Vp and Vs anomalies region along Bukit Barisan which is may be associated with weak zone of Sumatran fault and migration of partial melted material. Low velocity anomalies at 30-50 km depth in the fore arc region may indicated the hydrous material circulation because the slab dehydration. We detected low seismic seismicity in the fore arc region that may be indicated as seismic gap. It is coincides contact zone of high and low velocity anomalies. And two large earthquakes (Jambi and Mentawai) also occurred at the contact of contrast velocity.

  12. CASTLE3D - A Computer Aided System for Labelling Archaeological Excavations in 3D

    Houshiar, H.; Borrmann, D.; Elseberg, J.; Nüchter, A.; Näth, F.; Winkler, S.

    2015-08-01

    Documentation of archaeological excavation sites with conventional methods and tools such as hand drawings, measuring tape and archaeological notes is time consuming. This process is prone to human errors and the quality of the documentation depends on the qualification of the archaeologist on site. Use of modern technology and methods in 3D surveying and 3D robotics facilitate and improve this process. Computer-aided systems and databases improve the documentation quality and increase the speed of data acquisition. 3D laser scanning is the state of the art in modelling archaeological excavation sites, historical sites and even entire cities or landscapes. Modern laser scanners are capable of data acquisition of up to 1 million points per second. This provides a very detailed 3D point cloud of the environment. 3D point clouds and 3D models of an excavation site provide a better representation of the environment for the archaeologist and for documentation. The point cloud can be used both for further studies on the excavation and for the presentation of results. This paper introduces a Computer aided system for labelling archaeological excavations in 3D (CASTLE3D). Consisting of a set of tools for recording and georeferencing the 3D data from an excavation site, CASTLE3D is a novel documentation approach in industrial archaeology. It provides a 2D and 3D visualisation of the data and an easy-to-use interface that enables the archaeologist to select regions of interest and to interact with the data in both representations. The 2D visualisation and a 3D orthogonal view of the data provide cuts of the environment that resemble the traditional hand drawings. The 3D perspective view gives a realistic view of the environment. CASTLE3D is designed as an easy-to-use on-site semantic mapping tool for archaeologists. Each project contains a predefined set of semantic information that can be used to label findings in the data. Multiple regions of interest can be joined under

  13. Health risks from computed tomographic screening.

    Krantz, Seth B; Meyers, Bryan F

    2015-05-01

    Results of the recent National Lung Cancer Screening Trial show a significant survival benefit for annual screening with a low-dose computed tomographic (CT) scan in high-risk individuals. This result has led the US Preventive Services Task Force to recommend annual low-dose CT scans for this at-risk population. Less well characterized are the risks from screening. The primary risks from screening are radiation exposure, false-positive results and unnecessary diagnostic and therapeutic procedures, overdiagnosis and overtreatment, and increased psychological distress. This article reviews these risks, which must be considered and weighed against the benefits when discussing enrollment with patients. PMID:25901559

  14. Computed tomographic findings in acute infantile hemiplegia

    The clinical and computed tomographic findings in four cases of acute infantile hemiplegia that were followed for over ten years are described. The most impressive and common findings in four cases are as follows: 1) Unilateral loss of cerebral volume with displacement of the midline structures to the affected side. 2) Unilateral thicked calvarium and dilated frontal and ethmoid sinus and mastoid air cells on affected side. 3) A dilated lateral ventricle in the affected hemisphere. The recongnition of these calvarial changes should indicate that the cerebral abnormalities are the result of an atrophic and hypoplastic process that began in early life. (author)

  15. Cranial computed tomographic abnormalities in leptomeningeal metastasis

    Sixty-four (57.6%) of 111 cancer patients with cerebrospinal fluid cytology positive for malignant cells had cranial computed tomographic (CT) scans within 2 weeks before or after a lumbar puncture. Twenty-two (34.3%) of the 64 had abnormal CT findings indicative of leptomeningeal metastasis. Thirteen (59.6%) of these 22 patients had associated parenchymal metastases. Recognition of leptomeningeal disease may alter the management of patients with parenchymal metastases. Communicating hydrocephalus in cancer patients should be considered to be related to leptomeningeal metastasis until proven otherwise

  16. Computed tomographic analysis of urinary calculi

    Newhouse, J.H.; Prien, E.L.; Amis, E.S. Jr.; Dretler, S.P.; Pfister, R.C.

    1984-03-01

    Excised urinary calculi were subjected to computed tomographic (CT) scanning in an attempt to determine whether CT attenuation values would allow accurate analysis of stone composition. The mean, maximum, and modal pixel densities of the calculi were recorded and compared; the resulting values reflected considerable heterogeneity in stone density. Although uric acid and cystine calculi could be identified by their discrete ranges on one or more of these criteria, calcium-containing stones of various compositions, including struvite, could not be distinguished reliably. CT analysis of stone density is not likely to be more accurate than standard radiography in characterizing stone composition in vivo.

  17. 3D tomographic reconstruction of the internal velocity field of an immiscible drop in a shear flow

    Kerdraon, Paul; Dalziel, Stuart B.; Goldstein, Raymond E.; Landel, Julien R.; Peaudecerf, Francois J.

    2015-11-01

    We study experimentally the internal flow of a drop attached to a flat substrate and immersed in an immiscible shear flow. Transport inside the drop can play a crucial role in cleaning applications. Internal advection can enhance the mass transfer across the drop surface, thus increasing the cleaning rate. We used microlitre water-glycerol drops on a hydrophobic substrate. The drops were spherical and did not deform significantly under the shear flow. An oil phase of relative viscosity 0.01 to 1 was flowed over the drop. Typical Reynolds numbers inside the drops were of the order of 0.1 to 10. Using confocal microscopy, we performed 3D tomographic reconstruction of the flow field in the drop. The in-plane velocity field was measured using micro-PIV, and the third velocity component was computed from incompressibility. To our knowledge, this study gives the first experimental measurement of the three-dimensional internal velocity field of a drop in a shear flow. Numerical simulations and theoretical models published in the past 30 years predict a toroidal internal recirculation flow, for which the entire surface flows streamwise. However, our measurements reveal a qualitatively different picture with a two-lobed recirculation, featuring two stagnation points at the surface and a reverse surface flow closer to the substrate. This finding appears to be independent of Reynolds number and viscosity ratio in the ranges studied; we conjecture that the observed flow is due to the effect of surfactants at the drop surface.

  18. Computed tomographic features of canine nonparenchymal hemangiosarcoma.

    Fukuda, Shoko; Kobayashi, Tetsuya; Robertson, Ian D; Oshima, Fukiko; Fukazawa, Eri; Nakano, Yuko; Ono, Shin; Thrall, Donald E

    2014-01-01

    The purpose of this retrospective study was to describe pre- and postcontrast computed tomographic (CT) characteristics of confirmed nonparenchymal hemangiosarcoma in a group of dogs. Medical records were searched during the period of July 2003 and October 2011 and dogs with histologically confirmed nonparenchymal hemangiosarcoma and pre- and postcontrast CT images were recruited. Two observers recorded a consensus opinion for the following CT characteristics for each dog: largest transverse tumor diameter, number of masses, general tumor shape, character of the tumor margin, precontrast appearance, presence of dystrophic calcification, presence of postcontrast enhancement, pattern of postcontrast enhancement, presence of regional lymphadenopathy, and presence of associated cavitary fluid. A total of 17 dogs met inclusion criteria. Tumors were located in the nasal cavity, muscle, mandible, mesentery, subcutaneous tissue, and retroperitoneal space. Computed tomographic features of nonparenchymal hemangiosarcoma were similar to those of other soft tissue sarcomas, with most tumors being heterogeneous in precontrast images, invasive into adjacent tissue, and heterogeneously contrast enhancing. One unexpected finding was the presence of intense foci of contrast enhancement in 13 of the 17 tumors (76%). This appearance, which is not typical of other soft tissue sarcomas, was consistent with contrast medium residing in vascular channels. Findings indicated that there were no unique distinguishing CT characteristics for nonparenchymal hemangiosarcoma in dogs; however, the presence of highly attenuating foci of contrast enhancement may warrant further investigation in prospective diagnostic sensitivity and treatment outcome studies. PMID:24382330

  19. Computed tomographic features of cerebellar hemangioblastoma

    Park, Yong Lan; Ko, Young Tae; Kim, Ho Kyun [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1980-06-15

    Computed tomographic and angiographic findings of 6 proven cerebellar Hemangiotoma seen in this hospital during last 2 years were analyzed. The results were as follows: 1. Except one 14 years old female, all of them wee 37 to 48 years old males. 2. The operative findings of the tumors were 3 cystic tumors with mural nodules and 3 solid tumors. Computed tomographic findings were: 3. Of three cases of cystic cerebellar hemangiotomas, 2 cases revealed characteristic CT findings such as; a. In precontrast study, a well defined round lower density containing one isodense nodule in its periphery was seen in each case. The absorption coefficiency of each lower density was around 5 EMI unit. b. In post contrast study, the nodules were enhanced densely and homogeneously white the lower densities remain unchanged. 4. Of three cases of solid cerebella hemangiotoma, 2 cases revealed isodense mass suggested by mass effect such as displaced 4th ventricle and peripheral edema in precontrast study, while the remaining case revealed ill defined slightly high density with peripheral edema. In postcontrast study, the 2 isodense masses showed well circumscribed homogenous enhancement with central slight lower density in one of them, while high density mass revealed no enhancement at all. 5. The vertebral angiography performed in 5 cases revealed high vascular tumors with feeding arteries, draining veins and increased circulation time. 6. The tumor blushing seen in vertebral angiography was correlated to the postcontrast enhancement of solid tumors and mural nodules in cystic hemangioblastoma.

  20. A 3-D tomographic retrieval approach with advection compensation for the air-borne limb-imager GLORIA

    J. Ungermann

    2011-11-01

    Full Text Available Infrared limb sounding from aircraft can provide 2-D curtains of multiple trace gas species. However, conventional limb sounders view perpendicular to the aircraft axis and are unable to resolve the observed airmass along their line-of-sight. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere is a new remote sensing instrument that is able to adjust its horizontal view angle with respect to the aircraft flight direction from 45° to 135°. This will allow for tomographic measurements of mesoscale structures for a wide variety of atmospheric constituents.

    Many flights of the GLORIA instrument will not follow closed curves that allow measuring an airmass from all directions. Consequently, it is examined by means of simulations, what spatial resolution can be expected under ideal conditions from tomographic evaluation of measurements made during a straight flight. It is demonstrated that the achievable horizontal resolution in the line-of-sight direction could be reduced from over 200 km to around 70 km compared to conventional retrievals and that the tomographic retrieval is also more robust against horizontal gradients in retrieved quantities in this direction. In a second step, it is shown that the incorporation of channels exhibiting different optical depth can further enhance the spatial resolution of 3-D retrievals enabling the exploitation of spectral samples usually not used for limb sounding due to their opacity.

    A second problem for tomographic retrievals is that advection, which can be neglected for conventional retrievals, plays an important role for the time-scales involved in a tomographic measurement flight. This paper presents a method to diagnose the effect of a time-varying atmosphere on a 3-D retrieval and demonstrates an effective way to compensate for effects of advection by incorporating wind-fields from meteorological datasets as a priori information.

  1. Feasibility and value of fully 3D Monte Carlo reconstruction in single photon emission computed tomography

    The accuracy of Single Photon Emission Computed Tomography (SPECT) images is degraded by physical effects, namely photon attenuation, Compton scatter and spatially varying collimator response. The 3D nature of these effects is usually neglected by the methods used to correct for these effects. To deal with the 3D nature of the problem, a 3D projector modeling the spread of photons in 3D can be used in iterative tomographic reconstruction. The 3D projector can be estimated analytically with some approximations, or using precise Monte Carlo simulations. This latter approach has not been applied to fully 3D reconstruction yet due to impractical storage and computation time. The goal of this paper was to determine the gain to be expected from fully 3D Monte Carlo (F3DMC) modeling of the projector in iterative reconstruction, compared to conventional 2D and 3D reconstruction methods. As a proof-of-concept, two small datasets were considered. The projections of the two phantoms were simulated using the Monte Carlo simulation code GATE, as well as the corresponding projector, by taking into account all physical effects (attenuation, scatter, camera point spread function) affecting the imaging process. F3DMC was implemented by using this 3D projector in a maximum likelihood expectation maximization (MLEM) iterative reconstruction. To assess the value of F3DMC, data were reconstructed using 4 methods: filtered backprojection (FBP), MLEM without attenuation correction (MLEM), MLEM with attenuation correction, Jaszczak scatter correction and 3D correction for depth-dependent spatial resolution using an analytical model (MLEMC) and F3DMC. Our results suggest that F3DMC improves mainly imaging sensitivity and signal-to-noise ratio (SNR): sensitivity is multiplied by about 103 and SNR is increased by 20 to 70% compared to MLEMC. Computation of a more robust projector and application of the method on more realistic datasets are currently under investigation. (authors)

  2. Computed tomographic investigations on intraventricular hematomas

    This work investigated in 106 patients with intraventricular hematomas all the known factors which can have an influence on prognosis: age, sex, anamnesis of the patients, size, extent and localization of the intracranial bleeding, underlying angiopathy and differences between arterial and venous and spontaneous and traumatic bleedings. It was shown that the state of mind was the deciding prognostic factor, whereby viligance was the cumulative expression of all other investigated influences. A computed tomography (CT) examination is deciding in the question of operative hydrocephalus care. In 13 patients it was further shown, how clearly CT results and brain dissection allowed themselves to be compared. The computed tomographic examination method is best suited to achieve even physiological and more extensive prognostic possibilities. (orig.)

  3. Benchmark for a 3D Monte Carlo boiling water reactor fluence computational package - MF3D

    A detailed three dimensional model of a quadrant of an operating BWR has been developed using MCNP to calculate flux spectrum and fluence levels at various locations in the reactor system. The calculational package, MF3D, was benchmarked against test data obtained over a complete fuel cycle of the host BWR. The test package included activation wires sensitive in both the fast and thermal ranges. Comparisons between the calculational results and test data are good to within ten percent, making the MF3D package an accurate tool for neutron and gamma fluence computation in BWR pressure vessel internals. (orig.)

  4. E-learn Computed Tomographic Angiography

    Havsteen, Inger; Christensen, Anders; Nielsen, Jens K;

    2012-01-01

    BACKGROUND: Computed tomographic angiography (CTA) is widely available in emergency rooms to assess acute stroke patients. To standardize readings and educate new readers, we developed a 3-step e-learning tool based on the test-teach-retest methodology in 2 acute stroke scenarios: vascular...... occlusion and "spot sign" in acute intracerebral hemorrhage. We hypothesized that an e-learning program enhances reading skills in physicians of varying experience. METHODS: We developed an HTML-based program with a teaching segment and 2 matching test segments. Tests were taken before and after the...... sign correctly 69% before versus 92% after teaching (P = .009) and reported a median self-perceived diagnostic certainty of 50% versus 75% (P = .030). Self-perceived diagnostic certainty revealed no significant increase for vascular occlusion. CONCLUSIONS: The e-learning program is a useful educational...

  5. Towards 3C-3D digital holographic fluid velocity vector field measurement—tomographic digital holographic PIV (Tomo-HPIV)

    Most unsteady and/or turbulent flows of geophysical and engineering interest have a highly three-dimensional (3D) complex topology and their experimental investigation is in pressing need of quantitative velocity measurement methods that are robust and can provide instantaneous 3C-3D velocity field data over a significant volumetric domain of the flow. This paper introduces and demonstrates a new method that uses multiple digital CCD array cameras to record in-line digital holograms of the same volume of seed particles from multiple orientations. This technique uses the same basic equipment as Tomo-PIV minus the camera lenses, it overcomes the depth-of-field problem of digital in-line holography and does not require the complex optical calibration of Tomo-PIV. The digital sensors can be oriented in an optimal manner to overcome the depth-of-field limitation of in-line holograms recorded using digital CCD or CMOS array cameras, resulting in a 3D reconstruction of the seed particles within the volume of interest, which can subsequently be analysed using 3D cross-correlation PIV analysis to yield a 3C-3D velocity field. A demonstration experiment of Tomo-HPIV using uniform translation with nominally 11 µm diameter seed particles shows that the 3D displacement derived from 3D cross-correlation Tomo-HPIV analysis can be measured within 5% of the imposed uniform translation, where the imposed uniform translation has an estimated standard uncertainty of 4.3%. So this paper proposes a multi-camera digital holographic imaging 3C-3D PIV method, which is identified as tomographic digital holographic PIV or Tomo-HPIV

  6. Registration of Real-Time 3-D Ultrasound to Tomographic Images of the Abdominal Aorta.

    Brekken, Reidar; Iversen, Daniel Høyer; Tangen, Geir Arne; Dahl, Torbjørn

    2016-08-01

    The purpose of this study was to develop an image-based method for registration of real-time 3-D ultrasound to computed tomography (CT) of the abdominal aorta, targeting future use in ultrasound-guided endovascular intervention. We proposed a method in which a surface model of the aortic wall was segmented from CT, and the approximate initial location of this model relative to the ultrasound volume was manually indicated. The model was iteratively transformed to automatically optimize correspondence to the ultrasound data. Feasibility was studied using data from a silicon phantom and in vivo data from a volunteer with previously acquired CT. Through visual evaluation, the ultrasound and CT data were seen to correspond well after registration. Both aortic lumen and branching arteries were well aligned. The processing was done offline, and the registration took approximately 0.2 s per ultrasound volume. The results encourage further patient studies to investigate accuracy, robustness and clinical value of the approach. PMID:27156015

  7. Design for scalability in 3D computer graphics architectures

    Holten-Lund, Hans Erik

    2002-01-01

    This thesis describes useful methods and techniques for designing scalable hybrid parallel rendering architectures for 3D computer graphics. Various techniques for utilizing parallelism in a pipelines system are analyzed. During the Ph.D study a prototype 3D graphics architecture named Hybris has...... been developed. Hybris is a prototype rendering architeture which can be tailored to many specific 3D graphics applications and implemented in various ways. Parallel software implementations for both single and multi-processor Windows 2000 system have been demonstrated. Working hardware...... as a case study and an application of the Hybris graphics architecture....

  8. 3D Imaging of Buried Dielectric Targets with a Tomographic Microwave Approach Applied to GPR Synthetic Data

    Alessandro Galli

    2013-01-01

    Full Text Available Effective diagnostics with ground penetrating radar (GPR is strongly dependent on the amount and quality of available data as well as on the efficiency of the adopted imaging procedure. In this frame, the aim of the present work is to investigate the capability of a typical GPR system placed at a ground interface to derive three-dimensional (3D information on the features of buried dielectric targets (location, dimension, and shape. The scatterers can have size comparable to the resolution limits and can be placed in the shallow subsurface in the antenna near field. Referring to canonical multimonostatic configurations, the forward scattering problem is analyzed first, obtaining a variety of synthetic GPR traces and radargrams by means of a customized implementation of an electromagnetic CAD tool. By employing these numerical data, a full 3D frequency-domain microwave tomographic approach, specifically designed for the inversion problem at hand, is applied to tackle the imaging process. The method is tested here by considering various scatterers, with different shapes and dielectric contrasts. The selected tomographic results illustrate the aptitude of the proposed approach to recover the fundamental features of the targets even with critical GPR settings.

  9. Results of comparative RBMK neutron computation using VNIIEF codes (cell computation, 3D statics, 3D kinetics). Final report

    In conformity with the protocol of the Workshop under Contract open-quotes Assessment of RBMK reactor safety using modern Western Codesclose quotes VNIIEF performed a neutronics computation series to compare western and VNIIEF codes and assess whether VNIIEF codes are suitable for RBMK type reactor safety assessment computation. The work was carried out in close collaboration with M.I. Rozhdestvensky and L.M. Podlazov, NIKIET employees. The effort involved: (1) cell computations with the WIMS, EKRAN codes (improved modification of the LOMA code) and the S-90 code (VNIIEF Monte Carlo). Cell, polycell, burnup computation; (2) 3D computation of static states with the KORAT-3D and NEU codes and comparison with results of computation with the NESTLE code (USA). The computations were performed in the geometry and using the neutron constants presented by the American party; (3) 3D computation of neutron kinetics with the KORAT-3D and NEU codes. These computations were performed in two formulations, both being developed in collaboration with NIKIET. Formulation of the first problem maximally possibly agrees with one of NESTLE problems and imitates gas bubble travel through a core. The second problem is a model of the RBMK as a whole with imitation of control and protection system controls (CPS) movement in a core

  10. Multitasking the code ARC3D. [for computational fluid dynamics

    Barton, John T.; Hsiung, Christopher C.

    1986-01-01

    The CRAY multitasking system was developed in order to utilize all four processors and sharply reduce the wall clock run time. This paper describes the techniques used to modify the computational fluid dynamics code ARC3D for this run and analyzes the achieved speedup. The ARC3D code solves either the Euler or thin-layer N-S equations using an implicit approximate factorization scheme. Results indicate that multitask processing can be used to achieve wall clock speedup factors of over three times, depending on the nature of the program code being used. Multitasking appears to be particularly advantageous for large-memory problems running on multiple CPU computers.

  11. Practical rendering and computation with Direct3D 11

    Zink, Jason; Hoxley, Jack

    2011-01-01

    Practical Rendering and Computation with Direct3D 11 packs in documentation and in-depth coverage of basic and high-level concepts related to using Direct 3D 11 and is a top pick for any serious programming collection. … perfect for a wide range of users. Any interested in computation and multicore models will find this packed with examples and technical applications.-Midwest Book Review, October 2011The authors have generously provided us with an optimal blend of concepts and philosophy, illustrative figures to clarify the more difficult points, and source code fragments to make the ideas con

  12. Computed tomographic study of maxillofacial gunshot injuries

    The purpose of this study was to evaluate the clinical and computed tomographic features of 7 cases of maxillofacial al gunshot injuries in the suicidal patients visited the emergency room, Capital Armed Forces General Hospital. The obtained results were as follows: 1. The gunshot wounds were directed from submental area to dorsum of nose (3 cases), frontal area (1 case), orbit (1 case ), infraorbital area (1 case), and lateral to nasal wing (1 case), The shape of inlet in gunshot wounds were round (diameter : 13cm) and that of outlet were oval shape (size : inlet< outlet). 2. The bullet fragment wasn't found in 2 cases, but in the other 5 cases, the bullet fragments were showed in facial area. 3. All cases showed the fracture on anterior mandible (5 cases : comminuted fracture), and 1 case showed the comminuted fracture on mandibular body. The maxilla were comminutedly fractured in all cases, the fracture of mixillary teeth were showed and in 3 cases the fracture of mandibular teeth were showed. 4. The comminuted fracture on nasal bone and fracture on nasal septum occurred in 6 cases. 5. the cases of injuries on paranasal sinus were 5 cases of fracture on mixillary sinus, 4 cases of fracture on ethmoid al sinus, 2 cases of fracture on frontal sinus. this every fractured paranasal sinus showed air-fluid level or non-aera tion state. 6. Obstruction of supralaryngeal airway occurred in 6 cases.

  13. Computed tomographic findings of intracerebral cysticercosis

    Hong, Jin Kyo; Lee, Sun Wha; Kim, Ho Kyun; Ahn, Chi Yul [School of Medicine, Kyung-Hee University, Seoul (Korea, Republic of)

    1980-12-15

    Cysticercosis is a parasitic disease in which man serves as the intermediate host of Taenia Solium, the pork tapeworm. The computed tomographic findings of 25 cases of intracerebral cysticercosis proven by pathologic and/or clinical findings during past 2 years were analysed. The results were as follows; 1. The sex was 19 males and 6 females, and 56 percent of the patients were seen in fourth and fifth decades. The most common symptom was epilepsy (72%). 2. The C. T. findings in precontrast study were varied; such as ill defined low density (48%), cystic low density (20%), dilated ventricles (20%), ill defined low density with isodense nodule (18%), cystic low density with isodense mural nodule (12%) and calcification (8%). 3. The areas of involvement were 20 cases (80%) of parenchymal form, 3 cases (12%) of ventricular form and 2 cases (8%) of mixed form. 4. The contrast-enhanced 13 cases were 5 nodular, 5 ring or rim-like and 3 mixed type enhancements, while 12 cases were not enhanced. 5. C.T. scan demonstrated more precise location and extents of cerebral cysticercosis, especially in parenchymal form. It was considered to be important in determination of surgical feasibility and its approach.

  14. Computed tomographic findings of intracerebral cysticercosis

    Cysticercosis is a parasitic disease in which man serves as the intermediate host of Taenia Solium, the pork tapeworm. The computed tomographic findings of 25 cases of intracerebral cysticercosis proven by pathologic and/or clinical findings during past 2 years were analysed. The results were as follows; 1. The sex was 19 males and 6 females, and 56 percent of the patients were seen in fourth and fifth decades. The most common symptom was epilepsy (72%). 2. The C. T. findings in precontrast study were varied; such as ill defined low density (48%), cystic low density (20%), dilated ventricles (20%), ill defined low density with isodense nodule (18%), cystic low density with isodense mural nodule (12%) and calcification (8%). 3. The areas of involvement were 20 cases (80%) of parenchymal form, 3 cases (12%) of ventricular form and 2 cases (8%) of mixed form. 4. The contrast-enhanced 13 cases were 5 nodular, 5 ring or rim-like and 3 mixed type enhancements, while 12 cases were not enhanced. 5. C.T. scan demonstrated more precise location and extents of cerebral cysticercosis, especially in parenchymal form. It was considered to be important in determination of surgical feasibility and its approach

  15. Computed tomographic findings of postoperative maxillary cyst

    We studied computed tomographic findings in the axial sections of postoperative maxillary cyst diagnosed histopathologically. The results were as follows: 1. Nineteen patients (11 males and 8 females) were studied. The average age was 44.9 years and the average period after the initial surgery of maxillary sinus was 24.3 years. 2. The lesion occupied the maxillary sinus horizontally in 13 cases and the inferior border of the lesion extended to the alveolar area in 17 cases. The forms of the lesions fell into three types; absorbed bone type, simular sinus type and unsettled type. The lesion was unilocular in 15 cases. 3. The lesion protruded into the soft tissue in 15 cases. 4. The CT numbers of the lesions ranged from 28.5 to 73.0 H.U., and the average was 44.6 H.U. 5. In the bilateral surgery cases, the findings of the opposite side fell into three types; filled bone type, reduced cavity type and soft tissue density area type. (author)

  16. Computer tomographic imaging of rabbit bulbourethral glands

    The aim of the study was to utilize the obtained data for differentiation of normal and pathologically altered bulbourethral glands in rabbits with regard to using this animal species as a model for studying diseases in this organ in humans. MATERIAL AND METHODS: Ten sexually mature healthy male white New Zealand rabbits, 12 months old, weighed 2.8−3.2 kg were investigated. The animals were anesthetized. Scans were done at 2 mm intervals and the image reconstruction was three-dimensional. RESULTS: Rabbit bulbourethral glands were observed as a transversely oval homogeneous, relatively hyperdense structure against the surrounding soft tissues. They are visualized in the transverse cut of the pelvic outlet in the plane through the cranial part of cg2, the body of ischium, cranially to tuber ischiadicum and dorsally to the caudal part of symphysis pubis –sciatic arch. The glandular margins are adequately distinguished from the adjacent soft tissue structures. The density of the rabbit bulbourethral glands was similar to this of the soft tissues. CONCLUSION: The data obtained by the computed tomographic imaging of the rabbit bulbourethral glands could be used as an anatomical reference in the diagnosis and interpretation of imaging findings of various pathological states of the gland in this species, as well as in utilization of the rabbit as an animal model for studying diseases of this organ in humans, particularly diverticula, stenosis, lithiasis and valves

  17. TOMOGRAPHICAL APPROACH IN 3-D TEMEPEARTURE DISTRIBUTION MEASUREMENT BY DIGITAL HOLOGRAPHY

    Psota, Pavel; Doleček, Roman; Lédl, Vít; Vojtíšek, Petr; Vít, T.; Matoušek, Ondřej

    Prague : Czech Technical University in Prague, 2015. ISBN 978-80-01-05793-3. - (IMEKO). [Conference: XXI IMEKO World Congress 'Measurement in Research and Industry ', IMEKO. Prague (CZ), 30.08.2015-04.09.2015] Institutional support: RVO:61389021 Keywords : digital holography * holographic interferometry * temperature * 3-D measurement * tomography Subject RIV: JB - Sensors, Measurment, Regulation www.imeko2015.org

  18. Molecular-Frame 3D Photoelectron Momentum Distributions by Tomographic Reconstruction

    Maurer, Jochen; Dimitrovski, Darko; Christensen, Lauge; Madsen, Lars Bojer; Stapelfeldt, Henrik

    2012-01-01

    Naphthalene molecules are fixed in space by a laser field and rotated, in 2° steps, over 180°. For each orientation, they are ionized by an intense, circularly polarized femtosecond laser pulse, and the 2D projection of the photoelectron momentum distribution is recorded. The molecular-frame 3D...... very sensitive to the exact form of the laser-modified molecular potential....

  19. The 3D-SEEP computer code user's manual

    This report describes the 3D-SEEP computer code and presents the direction to use the code effectively. 3D-SEEP calculates the saturated-unsaturated time dependent or steady state flow of groundwater in permeable geologic media for the safety evaluation of nuclear waste disposal. 3D-SEEP is based on the 3-dimensional Galerkin finite element method. This allows the modeling of complex geometrical shapes and complicated patterns of geologic media. The flow is modeled by single phase flow governed by Darcy's law, and the simplified double porosity model is introduced to consider fractured media. This code can handle non-uniform flow regions having irregular boundaries and arbitrary degree of local anisotropy. (author)

  20. FUN3D and CFL3D Computations for the First High Lift Prediction Workshop

    Park, Michael A.; Lee-Rausch, Elizabeth M.; Rumsey, Christopher L.

    2011-01-01

    Two Reynolds-averaged Navier-Stokes codes were used to compute flow over the NASA Trapezoidal Wing at high lift conditions for the 1st AIAA CFD High Lift Prediction Workshop, held in Chicago in June 2010. The unstructured-grid code FUN3D and the structured-grid code CFL3D were applied to several different grid systems. The effects of code, grid system, turbulence model, viscous term treatment, and brackets were studied. The SST model on this configuration predicted lower lift than the Spalart-Allmaras model at high angles of attack; the Spalart-Allmaras model agreed better with experiment. Neglecting viscous cross-derivative terms caused poorer prediction in the wing tip vortex region. Output-based grid adaptation was applied to the unstructured-grid solutions. The adapted grids better resolved wake structures and reduced flap flow separation, which was also observed in uniform grid refinement studies. Limitations of the adaptation method as well as areas for future improvement were identified.

  1. A comparison of multi-scale 3D X-ray tomographic inspection techniques for assessing carbon fibre composite impact damage

    Bull, D. J.; Helfen, L.; Sinclair, I.; Spearing, S.M.; Baumbach, T.

    2013-01-01

    Tomographic imaging using both laboratory sources and synchrotron radiation (SR) was performed to achieve a multi-scale damage assessment of carbon fibre composites subjected to impact damage, allowing various internal damage modes to be studied in three-dimensions. The focus of this study is the comparison of different tomographic methods, identifying their capabilities and limitations, and their use in a complementary manner for creating an overall 3D damage assessment at both macroscopic a...

  2. The extent of the Cratonic keel underneath the Southern African region: A 3D image using Finite-Frequency Tomograph

    Soliman, Mohammad Youssof Ahmad; Bezada, Max; Thybo, Hans;

    2010-01-01

    We have re-examined the P body wave data from the South Africa Seismic Experiment (Carlson et al, EOS 77, 1996) across the Kaapvaal and Zimbabwe cratons and the Bushveld complex. Using finite-frequency kernels, we inverted the P-wave delay times to obtain 3-D images of compressional velocity...... damping parameter in the deeper layers progressively and examined the rms misfit and the imaged structure. Visual inspection of the tomographic images produced from these inversions showed that the lateral distribution of structures remained unchanged as the depth of the model was reduced and deep...... belts. We also image significant positive and negative anomalies (±3.0%) unconnected to the cratons under the cratonic keels and in the transition zone. We are currently inverting the P wave data using different reference models, and examining the S-wave travel times....

  3. The Use Of Computerized Tomographic (CT) Scans For 3-D Display And Prosthesis Construction

    Mankovich, Nicholas J.; Woodruff, Tracey J.; Beumer, John

    1985-06-01

    The construction of preformed cranial prostheses for large cranial bony defects is both error prone and time consuming. We discuss a method used for the creation of cranial prostheses from automatically extracted bone contours taken from Computerized Tomographic (CT) scans. Previous methods of prosthesis construction have relied on the making of a mold directly from the region of cranial defect. The use of image processing, bone contour extraction, and three-dimensional display allowed us to create a better fitting prosthesis while reducing patient surgery time. This procedure involves direct bone margin extraction from the digital CT images followed by head model construction from serial plots of the bone margin. Three-dimensional data display is used to verify the integrity of the skull data set prior to model construction. Once created, the model is used to fabricate a custom fitting prosthesis which is then surgically implanted. This procedure is being used with patients in the Maxillofacial Prosthetic Clinic at UCLA and this paper details the technique.

  4. The 3D tomographic image reconstruction software for prompt-gamma measurement of the boron neutron capture therapy

    A tomographic imaging system based on the spatial distribution measurement of the neutron capture reaction during Boron Neutron Capture Therapy (BNCT) would be very useful for clinical purpose. Using gamma-detectors in a 2D-panel, boron neutron capture and hydrogen neutron capture gamma-rays emitted by the neutron irradiated region can be detected, and an image of the neutron capture events can be reconstructed. A 3D reconstruction software package has been written to support the development of a 3D prompt-gamma tomographic system. The package consists of three independent modules: phantom generation, reconstruction and evaluation modules. The reconstruction modules are based on algebraic approach of the iterative reconstruction algorithm (ART), and on the maximum likelihood estimation method (ML-EM). In addition to that, two subsets of the ART, the simultaneous iterative reconstruction technique (SIRT) and the component averaging algorithms (CAV) have been included to the package employing parallel codes for multiprocessor architecture. All implemented algorithms use two different field functions for the reconstruction of the region. One is traditional voxel function, another is, so called, blob function, smooth spherically symmetric generalized Kaiser-Bessel function. The generation module provides the phantom and projections with background by tracing the prompt gamma-rays for a given scanner geometry. The evaluation module makes statistical comparisons between the generated and reconstructed images, and provides figure-of-merit (FOM) values for the applied reconstruction algorithms. The package has been written in C language and tested under Linux and Windows platforms. The simple graphical user interface (GUI) is used for command execution and visualization purposed. (author)

  5. Optical tomographic in-air scanner for external radiation beam 3D gel dosimetry

    Full text: Optical CT scanners are used to measure 3D radiation dose distributions in radiosensitive gels. For radiotherapy dose verification, 3D dose measurements are useful for verification of complex linear accelerator treatment planning and delivery techniques. Presently optical CTs require the use of a liquid bath to match the refractive index of the gel to minimise refraction of the light rays leading to distortion and artifacts. This work aims to develop a technique for scanning gel samples in free-air, without the requirement for a matching liquid bath. The scanner uses a He-Ne laser beam, fanned across the acrylic cylindrical gel container by a rotating mirror. The gel container was designed to produce parallel light ray paths through the gel. A pin phantom was used to quantify geometrical distortion of the reconstructed image, while uniform field exposures were used to consider noise, uniformity and artifacts. Small diameter wires provided an indication of the spatial resolution of the scanner. Pin phantom scans show geometrical distortion comparable to scanners using matching fluid baths. Noise, uniformity and artifacts were not found to be major limitations for this scanner approach. Spatial resolution was limited by laser beam spot size, typically 0.4 mm full width half maximum. A free-air optical CT scanner has been developed with the advantage of scanning without a matching fluid bath. Test results show it has potential to provide suitable quality 3D dosimetry measurements for external beam dose verification, while offering significant advantages in convenience and efficiency for routine use.

  6. Computer simulations of a low energy proton beam tomograph

    This work presents the recent development of a low energy proton beam tomograph. The proton tomograph prototype (involving UTFPR, UERJ, UFRJ and IEN/CNEN) has been installed and tested at the cyclotron CV-28 of IEN/CNEN. New computer simulations were performed in order to optimize the performance of the scattered proton beam and its aluminum collimator energy losses. The computer code simulates the tomographic measurements with two aluminum collimators (variable aperture from 0.2 mm to 0.4 mm in diameter and variable thickness from 4 mm to 8 mm), a water phantom and a Si(Li) detector. The analysis of the exit beam energy spectra in comparison with a perfectly collimated proton beam made it possible to achieve the best quality of reconstructed tomographic images of water phantom. (author)

  7. Computer simulations of a low energy proton beam tomograph

    Milhoretto, E.; Schelin, H.R.; Setti, J.A.P.; Denyak, V.; Paschuk, S.A.; Basilio, A.C.; Rocha, R.; Ribeiro Junior, S. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil). Curso de Pos-Graduacao em Engenharia Eletrica e Informatica Industrial (CPGEI)]. E-mails: sergei@utfpr.edu.br; edneymilhoretto@yahoo.com; schelin@cpgei.cefetpr.br; Evseev, I.; Yevseyeva, O. [Universidade Estadual do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil)]. E-mail: evseev@iprj.uerj.br; Lopes, R.T. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graducao em Engenharia (COPPE). Lab. de Instrumentacao Nuclear]. E-mail: ricardo@lin.ufrj.br; Vinagre Filho, U.M. [Instituto de Energia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2007-07-01

    This work presents the recent development of a low energy proton beam tomograph. The proton tomograph prototype (involving UTFPR, UERJ, UFRJ and IEN/CNEN) has been installed and tested at the cyclotron CV-28 of IEN/CNEN. New computer simulations were performed in order to optimize the performance of the scattered proton beam and its aluminum collimator energy losses. The computer code simulates the tomographic measurements with two aluminum collimators (variable aperture from 0.2 mm to 0.4 mm in diameter and variable thickness from 4 mm to 8 mm), a water phantom and a Si(Li) detector. The analysis of the exit beam energy spectra in comparison with a perfectly collimated proton beam made it possible to achieve the best quality of reconstructed tomographic images of water phantom. (author)

  8. Advanced computational tools for 3-D seismic analysis

    Barhen, J.; Glover, C.W.; Protopopescu, V.A. [Oak Ridge National Lab., TN (United States)] [and others

    1996-06-01

    The global objective of this effort is to develop advanced computational tools for 3-D seismic analysis, and test the products using a model dataset developed under the joint aegis of the United States` Society of Exploration Geophysicists (SEG) and the European Association of Exploration Geophysicists (EAEG). The goal is to enhance the value to the oil industry of the SEG/EAEG modeling project, carried out with US Department of Energy (DOE) funding in FY` 93-95. The primary objective of the ORNL Center for Engineering Systems Advanced Research (CESAR) is to spearhead the computational innovations techniques that would enable a revolutionary advance in 3-D seismic analysis. The CESAR effort is carried out in collaboration with world-class domain experts from leading universities, and in close coordination with other national laboratories and oil industry partners.

  9. 3D computer visualization and animation of CANDU reactor core

    Three-dimensional (3D) computer visualization and animation models of typical CANDU reactor cores (Darlington, Point Lepreau) have been developed using world-wide-web (WWW) browser based tools: JavaScript, hyper-text-markup language (HTML) and virtual reality modeling language (VRML). The 3D models provide three-dimensional views of internal control and monitoring structures in the reactor core, such as fuel channels, flux detectors, liquid zone controllers, zone boundaries, shutoff rods, poison injection tubes, ion chambers. Animations have been developed based on real in-core flux detector responses and rod position data from reactor shutdown. The animations show flux changing inside the reactor core with the drop of shutoff rods and/or the injection of liquid poison. The 3D models also provide hypertext links to documents giving specifications and historical data for particular components. Data in HTML format (or other format such as PDF, etc.) can be shown in text, tables, plots, drawings, etc., and further links to other sources of data can also be embedded. This paper summarizes the use of these WWW browser based tools, and describes the resulting 3D reactor core static and dynamic models. Potential applications of the models are discussed. (author)

  10. PID - 3D: a software to develop mathematical human phantoms for use in computational dosimetry

    The PID-3D software, written in Visual C++, contains tools developed for building and editing of three-dimensional geometric figures formed of voxels (volume pixels). These tools were projected to be used, together with those already developed by the Grupo de Dosimetria Numerica (GDN/CNPq), such as the FANTOMAS and DIP software, in computational dosimetry of ionizing radiation. The main objective of this paper is to develop various voxel-based geometric solids to build voxel phantoms (meaning models), anthropomorphic or not. The domain of this technique of development of geometric solids is important for the GDN/CNPq, because it allows the use of just one Monte Carlo code to simulate the transportation, interaction and deposition of radiation in tomographic and mathematical phantoms. Building a particular geometric solid the user needs to inform to the PID-3D software, the location and the size of the parallelepiped that involves it. Each built solid can be saved in a binary file of the type SGI (file containing the size and the numeric values that constitutes the 3D matrix that represents the solid, commonly used by GDN/CNPq). The final mathematical phantom is built starting from these SGI files and the SGI file resulting constitutes a voxel phantom. With this approach the software's user does not have to manipulate the equations and inequalities of the solids that represent the organs and tissues of the phantom. The 3D-PID software, associated with the FANTOMAS and DIP software are tools produced by GDN/CNPq, providing a new technique for building of 3D scenes in dosimetric evaluations using voxel phantoms. To validate the PID-3D software one built, step by step, a phantom similar to the MIRD-5 stylized phantom. (author)

  11. Computing Radiative Transfer in a 3D Medium

    Von Allmen, Paul; Lee, Seungwon

    2012-01-01

    A package of software computes the time-dependent propagation of a narrow laser beam in an arbitrary three- dimensional (3D) medium with absorption and scattering, using the transient-discrete-ordinates method and a direct integration method. Unlike prior software that utilizes a Monte Carlo method, this software enables simulation at very small signal-to-noise ratios. The ability to simulate propagation of a narrow laser beam in a 3D medium is an improvement over other discrete-ordinate software. Unlike other direct-integration software, this software is not limited to simulation of propagation of thermal radiation with broad angular spread in three dimensions or of a laser pulse with narrow angular spread in two dimensions. Uses for this software include (1) computing scattering of a pulsed laser beam on a material having given elastic scattering and absorption profiles, and (2) evaluating concepts for laser-based instruments for sensing oceanic turbulence and related measurements of oceanic mixed-layer depths. With suitable augmentation, this software could be used to compute radiative transfer in ultrasound imaging in biological tissues, radiative transfer in the upper Earth crust for oil exploration, and propagation of laser pulses in telecommunication applications.

  12. 3D artefact for concurrent scale calibration in Computed Tomography

    Stolfi, Alessandro; De Chiffre, Leonardo

    2016-01-01

    A novel artefact for calibration of the scale in 3D X-ray Computed Tomography (CT) is presented. The artefact comprises a carbon fibre tubular structure on which a number of reference ruby spheres are glued. The artefact is positioned and scanned together with the workpiece inside the CT scanner...... providing a reference system for measurement. The artefact allows a considerable reduction of time by compressing the full process of calibration, scanning, measurement, and re-calibration, into a single process. The method allows a considerable reduction of the amount of data generated from CT scanning. A...

  13. Fully 3D tomographic reconstruction by Monte Carlo simulation of the system matrix in preclinical PET with iodine 124

    Immuno-PET imaging can be used to assess the pharmacokinetic in radioimmunotherapy. When using iodine-124, PET quantitative imaging is limited by physics-based degrading factors within the detection system and the object, such as the long positron range in water and the complex spectrum of gamma photons. The objective of this thesis was to develop a fully 3D tomographic reconstruction method (S(MC)2PET) using Monte Carlo simulations for estimating the system matrix, in the context of preclinical imaging with iodine-124. The Monte Carlo simulation platform GATE was used for that respect. Several complexities of system matrices were calculated, with at least a model of the PET system response function. Physics processes in the object was either neglected or taken into account using a precise or a simplified object description. The impact of modelling refinement and statistical variance related to the system matrix elements was evaluated on final reconstructed images. These studies showed that a high level of complexity did not always improve qualitative and quantitative results, owing to the high-variance of the associated system matrices. (author)

  14. 3D ultrasound computer tomography: update from a clinical study

    Hopp, T.; Zapf, M.; Kretzek, E.; Henrich, J.; Tukalo, A.; Gemmeke, H.; Kaiser, C.; Knaudt, J.; Ruiter, N. V.

    2016-04-01

    Ultrasound Computer Tomography (USCT) is a promising new imaging method for breast cancer diagnosis. We developed a 3D USCT system and tested it in a pilot study with encouraging results: 3D USCT was able to depict two carcinomas, which were present in contrast enhanced MRI volumes serving as ground truth. To overcome severe differences in the breast shape, an image registration was applied. We analyzed the correlation between average sound speed in the breast and the breast density estimated from segmented MRIs and found a positive correlation with R=0.70. Based on the results of the pilot study we now carry out a successive clinical study with 200 patients. For this we integrated our reconstruction methods and image post-processing into a comprehensive workflow. It includes a dedicated DICOM viewer for interactive assessment of fused USCT images. A new preview mode now allows intuitive and faster patient positioning. We updated the USCT system to decrease the data acquisition time by approximately factor two and to increase the penetration depth of the breast into the USCT aperture by 1 cm. Furthermore the compute-intensive reflectivity reconstruction was considerably accelerated, now allowing a sub-millimeter volume reconstruction in approximately 16 minutes. The updates made it possible to successfully image first patients in our ongoing clinical study.

  15. 3D computer model of the VINCY cyclotron magnet

    The VINCY Cyclotron magnetic field simulation was performed with the help of the three-dimensional (3D) software. The following aspects of the system were considered: 3D calculation of the magnetic field in the median plane, 3D calculation of the magnetic field in the extraction region, 3D calculation of the stray magnetic field. 8 refs., 17 figs., 3 tabs

  16. Computational Modelling of Piston Ring Dynamics in 3D

    Dlugoš Jozef

    2014-12-01

    Full Text Available Advanced computational models of a piston assembly based on the level of virtual prototypes require a detailed description of piston ring behaviour. Considering these requirements, the piston rings operate in regimes that cannot, in general, be simplified into an axisymmetric model. The piston and the cylinder liner do not have a perfect round shape, mainly due to machining tolerances and external thermo-mechanical loads. If the ring cannot follow the liner deformations, a local loss of contact occurs resulting in blow-by and increased consumption of lubricant oil in the engine. Current computational models are unable to implement such effects. The paper focuses on the development of a flexible 3D piston ring model based on the Timoshenko beam theory using the multibody system (MBS. The MBS model is compared to the finite element method (FEM solution.

  17. Computation of 3D form factors in complex environments

    The calculation of radiant interchange among opaque surfaces in a complex environment poses the general problem of determining the visible and hidden parts of the environment. In many thermal engineering applications, surfaces are separated by radiatively non-participating media and may be idealized as diffuse emitters and reflectors. Consenquently the net radiant energy fluxes are intimately related to purely geometrical quantities called form factors, that take into account hidden parts: the problem is reduced to the form factor evaluation. This paper presents the method developed for the computation of 3D form factors in the finite-element module of the system TRIO, which is a general computer code for thermal and fluid flow analysis. The method is derived from an algorithm devised for synthetic image generation. A comparison is performed with the standard contour integration method also implemented and suited to convex geometries. Several illustrative examples of finite-element thermal calculations in radiating enclosures are given

  18. Effect of 3d computed microtomography resolution on reservoir rocks

    The objective of this study is to evaluate the quantification process of geometric parameters when different computed microtomography spatial resolutions are employed. To this end, one reservoir rock sample was scanned with a 3D high energy computed microtomography system. The results show a strong difference in the acquisition, reconstruction and image processes, but do not present a significant loss of information on the microstructural parameters in the higher resolutions. However, it has been significantly loss of information in the lower resolution. - Highlights: ► The potential of one reservoir can be know when porosity parameter is calculated. ► MicroCT was used in order to estimate volume and porosity of one carbonate rock. ► It was evaluated how the parameters are affected when different spatial resolutions are employed. ► We do not have a significant loss of information on when high resolution is applied

  19. Feasibility and value of fully 3D Monte Carlo reconstruction in single-photon emission computed tomography

    The accuracy of Single-Photon Emission Computed Tomography images is degraded by physical effects, namely photon attenuation, Compton scatter and spatially varying collimator response. The 3D nature of these effects is usually neglected by the methods used to correct for these effects. To deal with the 3D nature of the problem, a 3D projector modeling the spread of photons in 3D can be used in iterative tomographic reconstruction. The 3D projector can be estimated analytically with some approximations, or using precise Monte Carlo simulations. This latter approach has not been applied to fully 3D reconstruction yet due to impractical storage and computation time. The goal of this paper was to determine the gain to be expected from fully 3D Monte Carlo (F3DMC) modeling of the projector in iterative reconstruction, compared to conventional 2D and 3D reconstruction methods. As a proof-of-concept, two small datasets were considered. The projections of the two phantoms were simulated using the Monte Carlo simulation code GATE, as well as the corresponding projector, by taking into account all physical effects (attenuation, scatter, camera point spread function) affecting the imaging process. F3DMC was implemented by using this 3D projector in a maximum likelihood expectation maximization (MLEM) iterative reconstruction. To assess the value of F3DMC, data were reconstructed using four methods: filtered backprojection, MLEM without attenuation correction (MLEM), MLEM with attenuation correction, Jaszczak scatter correction and 3D correction for depth-dependent spatial resolution using an analytical model (MLEMC) and F3DMC. Our results suggest that F3DMC improves mainly imaging sensitivity and signal-to-noise ratio (SNR): sensitivity is multiplied by about 103 and SNR is increased by 20-70% compared to MLEMC. Computation of a more robust projector and application of the method on more realistic datasets are currently under investigation

  20. Glasses for 3D ultrasound computer tomography: phase compensation

    Zapf, M.; Hopp, T.; Ruiter, N. V.

    2016-03-01

    Ultrasound Computer Tomography (USCT), developed at KIT, is a promising new imaging system for breast cancer diagnosis, and was successfully tested in a pilot study. The 3D USCT II prototype consists of several hundreds of ultrasound (US) transducers on a semi-ellipsoidal aperture. Spherical waves are sequentially emitted by individual transducers and received in parallel by many transducers. Reflectivity volumes are reconstructed by synthetic aperture focusing (SAFT). However, straight forward SAFT imaging leads to blurred images due to system imperfections. We present an extension of a previously proposed approach to enhance the images. This approach includes additional a priori information and system characteristics. Now spatial phase compensation was included. The approach was evaluated with a simulation and clinical data sets. An increase in the image quality was observed and quantitatively measured by SNR and other metrics.

  1. Spiral computed tomographic imaging related to computerized ultrasonographic images of carotid plaque morphology and histology

    Grønholdt, Marie-Louise; Wagner, A; Wiebe, B M;

    2001-01-01

    Echolucency of carotid atherosclerotic plaques, as evaluated by computerized B-mode ultrasonographic images, has been associated with an increased incidence of brain infarcts on cerebral computed tomographic scans. We tested the hypotheses that characterization of carotid plaques on spiral computed...... tomographic images correlates with that on computerized B-mode ultrasonographic images and that spiral computed tomographic imaging predicts the histomorphometric plaque content....

  2. Analysis of bite marks in foodstuffs by computer tomography (cone beam CT)--3D reconstruction.

    Marques, Jeidson; Musse, Jamilly; Caetano, Catarina; Corte-Real, Francisco; Corte-Real, Ana Teresa

    2013-12-01

    The use of three-dimensional (3D) analysis of forensic evidence is highlighted in comparison with traditional methods. This three-dimensional analysis is based on the registration of the surface from a bitten object. The authors propose to use Cone Beam Computed Tomography (CBCT), which is used in dental practice, in order to study the surface and interior of bitten objects and dental casts of suspects. In this study, CBCT is applied to the analysis of bite marks in foodstuffs, which may be found in a forensic case scenario. 6 different types of foodstuffs were used: chocolate, cheese, apple, chewing gum, pizza and tart (flaky pastry and custard). The food was bitten into and dental casts of the possible suspects were made. The dental casts and bitten objects were registered using an x-ray source and the CBCT equipment iCAT® (Pennsylvania, EUA). The software InVivo5® (Anatomage Inc, EUA) was used to visualize and analyze the tomographic slices and 3D reconstructions of the objects. For each material an estimate of its density was assessed by two methods: HU values and specific gravity. All the used materials were successfully reconstructed as good quality 3D images. The relative densities of the materials in study were compared. Amongst the foodstuffs, the chocolate had the highest density (median value 100.5 HU and 1,36 g/cm(3)), while the pizza showed to have the lowest (median value -775 HU and 0,39 g/cm(3)), on both scales. Through tomographic slices and three-dimensional reconstructions it was possible to perform the metric analysis of the bite marks in all the foodstuffs, except for the pizza. These measurements could also be obtained from the dental casts. The depth of the bite mark was also successfully determined in all the foodstuffs except for the pizza. Cone Beam Computed Tomography has the potential to become an important tool for forensic sciences, namely for the registration and analysis of bite marks in foodstuffs that may be found in a crime

  3. Fixture-abutment connection surface and micro-gap measurements by 3D micro-tomographic technique analysis

    Deborah Meleo

    2012-01-01

    Full Text Available X-ray micro-tomography (micro-CT is a miniaturized form of conventional computed axial tomography (CAT able to investigate small radio-opaque objects at a-few-microns high resolution, in a nondestructive, non-invasive, and tri-dimensional way. Compared to traditional optical and electron microscopy techniques, which provide two-dimensional images, this innovative investigation technology enables a sample tri-dimensional analysis without cutting, coating or exposing the object to any particular chemical treatment. X-ray micro-tomography matches ideal 3D microscopy features: the possibility of investigating an object in natural conditions and without any preparation or alteration; non-invasive, non-destructive, and sufficiently magnified 3D reconstruction; reliable measurement of numeric data of the internal structure (morphology, structure and ultra-structure. Hence, this technique has multi-fold applications in a wide range of fields, not only in medical and odontostomatologic areas, but also in biomedical engineering, materials science, biology, electronics, geology, archaeology, oil industry, and semi-conductors industry. This study shows possible applications of micro-CT in dental implantology to analyze 3D micro-features of dental implant to abutment interface. Indeed, implant-abutment misfit is known to increase mechanical stress on connection structures and surrounding bone tissue. This condition may cause not only screw preload loss or screw fracture, but also biological issues in peri-implant tissues.

  4. Computational and methodological developments towards 3D full waveform inversion

    Etienne, V.; Virieux, J.; Hu, G.; Jia, Y.; Operto, S.

    2010-12-01

    Full waveform inversion (FWI) is one of the most promising techniques for seismic imaging. It relies on a formalism taking into account every piece of information contained in the seismic data as opposed to more classical techniques such as travel time tomography. As a result, FWI is a high resolution imaging process able to reach a spatial accuracy equal to half a wavelength. FWI is based on a local optimization scheme and therefore the main limitation concerns the starting model which has to be closed enough to the real one in order to converge to the global minimum. Another counterpart of FWI is the required computational resources when considering models and frequencies of interest. The task becomes even more tremendous when one tends to perform the inversion using the elastic equation instead of using the acoustic approximation. This is the reason why until recently most studies were limited to 2D cases. In the last few years, due to the increase of the available computational power, FWI has focused a lot of interests and continuous efforts towards inversion of 3D models, leading to remarkable applications up to the continental scale. We investigate the computational burden induced by FWI in 3D elastic media and propose some strategic features leading to the reduction of the numerical cost while providing a great flexibility in the inversion parametrization. First, in order to release the memory requirements, we developed our FWI algorithm in the frequency domain and take benefit of the wave-number redundancy in the seismic data to process a quite reduced number of frequencies. To do so, we extract frequency solutions from time marching techniques which are efficient for 3D structures. Moreover, this frequency approach permits a multi-resolution strategy by proceeding from low to high frequencies: the final model at one frequency is used as the starting model for the next frequency. This procedure overcomes partially the non-linear behavior of the inversion

  5. 3D Vectorial Time Domain Computational Integrated Photonics

    Kallman, J S; Bond, T C; Koning, J M; Stowell, M L

    2007-02-16

    The design of integrated photonic structures poses considerable challenges. 3D-Time-Domain design tools are fundamental in enabling technologies such as all-optical logic, photonic bandgap sensors, THz imaging, and fast radiation diagnostics. Such technologies are essential to LLNL and WFO sponsors for a broad range of applications: encryption for communications and surveillance sensors (NSA, NAI and IDIV/PAT); high density optical interconnects for high-performance computing (ASCI); high-bandwidth instrumentation for NIF diagnostics; micro-sensor development for weapon miniaturization within the Stockpile Stewardship and DNT programs; and applications within HSO for CBNP detection devices. While there exist a number of photonics simulation tools on the market, they primarily model devices of interest to the communications industry. We saw the need to extend our previous software to match the Laboratory's unique emerging needs. These include modeling novel material effects (such as those of radiation induced carrier concentrations on refractive index) and device configurations (RadTracker bulk optics with radiation induced details, Optical Logic edge emitting lasers with lateral optical inputs). In addition we foresaw significant advantages to expanding our own internal simulation codes: parallel supercomputing could be incorporated from the start, and the simulation source code would be accessible for modification and extension. This work addressed Engineering's Simulation Technology Focus Area, specifically photonics. Problems addressed from the Engineering roadmap of the time included modeling the Auston switch (an important THz source/receiver), modeling Vertical Cavity Surface Emitting Lasers (VCSELs, which had been envisioned as part of fast radiation sensors), and multi-scale modeling of optical systems (for a variety of applications). We proposed to develop novel techniques to numerically solve the 3D multi-scale propagation problem for both the

  6. Computed Tomographic Tenography of Normal Equine Digital Flexor Tendon Sheath: An Ex Vivo Study

    Luca Lacitignola

    2015-01-01

    Full Text Available Aim of this study was to document the normal computed tomographic tenography findings of digital flexor tendon sheath. Six ex vivo normal equine forelimbs were used. An axial approach was used to inject 185 mg/mL of iopamidol in a total volume of 60 mL into the digital flexor tendon sheaths. Single-slice helical scans, with 5 mm thickness, spaced every 3 mm, for a pitch of 0.6, and with bone algorithm reconstruction, were performed before and after injections of contrast medium. To obtain better image quality for multiplanar reconstruction and 3D reformatting, postprocessing retroreconstruction was performed to reduce the images to submillimetre thickness. Computed tomographic tenography of digital flexor tendon sheaths could visualize the following main tendon structures for every forelimb in contrast-enhanced images as low densities surrounded by high densities: superficial digital flexor tendon, deep digital flexor tendon, manica flexoria, mesotendons, and synovial recess. Results of this study suggest that computed tomographic tenography can be used with accuracy and sensitivity to evaluate the common disorders of the equine digital flexor tendon sheath and the intrathecal structures.

  7. A hybrid method for the computation of quasi-3D seismograms.

    Masson, Yder; Romanowicz, Barbara

    2013-04-01

    The development of powerful computer clusters and efficient numerical computation methods, such as the Spectral Element Method (SEM) made possible the computation of seismic wave propagation in a heterogeneous 3D earth. However, the cost of theses computations is still problematic for global scale tomography that requires hundreds of such simulations. Part of the ongoing research effort is dedicated to the development of faster modeling methods based on the spectral element method. Capdeville et al. (2002) proposed to couple SEM simulations with normal modes calculation (C-SEM). Nissen-Meyer et al. (2007) used 2D SEM simulations to compute 3D seismograms in a 1D earth model. Thanks to these developments, and for the first time, Lekic et al. (2011) developed a 3D global model of the upper mantle using SEM simulations. At the local and continental scale, adjoint tomography that is using a lot of SEM simulation can be implemented on current computers (Tape, Liu et al. 2009). Due to their smaller size, these models offer higher resolution. They provide us with images of the crust and the upper part of the mantle. In an attempt to teleport such local adjoint tomographic inversions into the deep earth, we are developing a hybrid method where SEM computation are limited to a region of interest within the earth. That region can have an arbitrary shape and size. Outside this region, the seismic wavefield is extrapolated to obtain synthetic data at the Earth's surface. A key feature of the method is the use of a time reversal mirror to inject the wavefield induced by distant seismic source into the region of interest (Robertsson and Chapman 2000). We compute synthetic seismograms as follow: Inside the region of interest, we are using regional spectral element software RegSEM to compute wave propagation in 3D. Outside this region, the wavefield is extrapolated to the surface by convolution with the Green's functions from the mirror to the seismic stations. For now, these

  8. Geometric approaches to computing 3D-landscape metrics

    M.-S. Stupariu

    2010-12-01

    Full Text Available The relationships between patterns and processes lie at the core of modern landscape ecology. These dependences can be quantified by using indices related to the patch-corridor-matrix model. This model conceptualizes landscapes as planar mosaics consisting of discrete patches. On the other hand, relief variability is a key factor for many ecological processes, and therefore these processes can be better modeled by integrating information concerning the third dimension of landscapes. This can be done by generating a triangle mesh which approximates the original terrain. The aim of this methodological paper is to introduce two new constructions of triangulations which replace a digital elevation model. These approximation methods are compared with the method which was already used in the computation of 3D-landscape metrics (firstly for parameterized surfaces and secondly for two landscape mosaics. The statistical analysis shows that all three methods are of almost equal sensitivity in reflecting the relationship between terrain ruggedness and the patches areas and perimeters. In particular, either of the methods can be used for approximating the real values of these basic metrics. However, the two methods introduced in this paper have the advantage of yielding continuous approximations of the terrain, and this fact could be useful for further developments.

  9. Computed tomographic findings in penetrating peptic ulcer

    Four cases of peptic ulcer penetrating the head of the pancreas were diagnosed by computed tomography (CT). Findings common to 3 cases included (a) an ulcer crater, (b) a sinus tract, and (c) enlargement of the head of the pancreas. Unlike other modalities, the inherent spatial resolution of CT allows a convenient diagnosis of this important complication of peptic ulcer disease

  10. Layered 3D: tomographic image synthesis for attenuation-based light field and high dynamic range displays

    Wetzstein, Gordon; Lanman, Douglas R.; Heidrich, Wolfgang; Raskar, Ramesh

    2011-01-01

    We develop tomographic techniques for image synthesis on displays composed of compact volumes of light-attenuating material. Such volumetric attenuators recreate a 4D light field or high-contrast 2D image when illuminated by a uniform backlight. Since arbitrary oblique views may be inconsistent with any single attenuator, iterative tomographic reconstruction minimizes the difference between the emitted and target light fields, subject to physical constraints on attenuation. As multi-layer gen...

  11. Dynamic computed tomographic scans in experimental brain abscess

    Dynamic computed tomographic scans were performed in an experimental brain abscess model to establish criteria that could be utilized in abscess staging. The vascular phase of the time-density curves did not differentiate cerebritis and capsule stages. The amount of residual enhancement after the first pass of an intra-arterial contrast bolus differed between major abscess stages, the greater residual enhancement being noted in the capsule stage. (orig.)

  12. Dynamic computed tomographic scans in experimental brain abscess

    Enzmann, D.R.; Britt, R.H.; Placone, R.C.

    1984-07-01

    Dynamic computed tomographic scans were performed in an experimental brain abscess model to establish criteria that could be utilized in abscess staging. The vascular phase of the time-density curves did not differentiate cerebritis and capsule stages. The amount of residual enhancement after the first pass of an intra-arterial contrast bolus differed between major abscess stages, the greater residual enhancement being noted in the capsule stage.

  13. Computer tomographic diagnosis of Caroli's syndrome

    Congenital cystic dilatation of the intrahepatic bile ducts - Caroli's syndrome - is a rare disease of which about one hundred cases have been reported in the literature. Based on two observations, the value of various radiological procedures is discussed. Compared with other noninvasive procedures, computer tomography has the advantage of being able to show not only the medullary sponge kidney which often accompanies this condition. The indications for ERC can therefore be more strictly defined. (orig.)

  14. Computed Tomographic Angiography (CTA) in Vascular Trauma

    M. Tehrai

    2007-01-01

    In the evaluation of trauma patients, computed tomo-graphy and CT angiography (CTA) are powerful non-invasive tools that provide a large amount of informa-tion in so little time that they have virtually replaced plain film radiography and catheter angiography. In our hospital, CTA has replaced catheter angiogra-phy for diagnosing most vascular injuries, resulting from penetrating and blunt trauma to head, neck, thorax, abdomen and extremities. This lecture will cover current imaging protocols...

  15. Computer Assisted Assessment within 3D Virtual Worlds

    Ibáñez, María Blanca; Morillo, Diego; Santos, Patricia; Perez Calle, David; García Rueda, José Jesús; Hernández-Leo, Davinia; Delgado Kloos, Carlos

    2011-01-01

    3D Virtual Worlds are currently been explored as learning environments due to their capabilities to promote learner motivation. Most of the research has been focused on the deployment of learning strategies on them. However, a crucial component of the teaching-learning process: the assessment has been neglected. In this work, we present an architecture that integrates an engine QTI-compliant with a 3D virtual world platform. The rich set of interactions that can occur in a 3D virtual environm...

  16. Computed tomographic evaluation of renal injuries

    Adequate radiographic demonstration of the extent of renal injury following blunt abdominal trauma is an important guide to therapy. The diagnostic evaluation of renal injuries usually begins with excretory urography, but not provide detailed information about the extent of injury. The need for a more accurate noninvasive modality led us to investigate the use of computed tomography. We evaluated with computed tomography and excretory urography 30 selected patients suspected of having major renal injury. Of these patients 11 were also underwent arteriography for assessment of renal arterial injuries. In this paper, we wish to analyze the result of the above modalities, particularly angiography and computed tomography. The brief results were as follow. 1. Among 30 patients, 21 cases were male and 9 cases were female. About one third of these occurred between the age of 20-29. 2. All cases were non penetrating blunt traumas. 3. Renal injuries were categorized into 3 groups. Category I is minor renal injuries (14 cases), II is major renal injuries (13 cases), and III is catastrophic renal injuries (3 cases). 4. IVP is the most common initial diagnostic modality and good for screening of patients, but lack of specificity. In our study the specificity is about 33%. 5. CT is more accurate in detecting hematoma, parenchymal laceration, fracture and extravasation of urine, but angiography is more confirmative in diagnosis of vascular injuries. 6. Conservative management was done in 19 cases; 13 cases of category I and 6 cases of II. Operation was performed in 11 cases; 1 case of category I, 7 cases of II and 3 cases of III. 7. Associated injuries were noted in 17 cases (57%).

  17. Computer tomographic anatomy of the neck

    Koenig, R.

    1984-01-01

    The structures in the neck which can be recognised by computer tomography, and their course, is described. The cartilagenous larynx and trachea, the oesophagus, thyroid, sternocleidomastoid muscle, common carotid arteries and internal jugular veins can be recognised regularly. In addition, one can identify smaller muscles, vessels and nerves, such as the sterno-hyoid, omo-hyoid, anterior and medial scalenus muscles, the superior and inferior thyroid arteries and the suprascapular, internal thoracic and vertebral arteries, the thyro-cervical trunk and the vagus and phrenic nerves. An accurate knowledge of the anatomy is essential for the recognition of enlarged parathyroid glands.

  18. Interactive 3D computer model of the human corneolimbal region

    Molvaer, Rikke Kongshaug; Andreasen, Arne; Heegaard, Steffen;

    2013-01-01

    plan. In all, one low-magnification and 24 high-magnification interactive 3D models were created. Immunohistochemistry against stem cell markers p63 and ΔNp63α was performed as a supplement to the 3D models. RESULTS: Using the interactive 3D models, we identified three types of stem cell niches......PURPOSE: This study aims to clarify the existence of and to map the localization of different proposed stem cell niches in the corneal limbal region. MATERIALS AND METHODS: One human eye was cut into 2200 consecutive sections. Every other section was stained with haematoxylin and eosin, digitized...... in the superior limbal region and one LEC, six LCs and 12 FSPs in the inferior limbal region. Only few LECs, LCs and FSPs were localized nasally and temporally. CONCLUSION: Interactive 3D models are a powerful tool that may help to shed more light on the existence and spatial localization of the different stem...

  19. Computed tomographic evaluation of intracranial metastasis

    Hong, Jin Kyo; Eun, Chung Kie; Kim, Soon Yong [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1982-09-15

    Computed tomography was proved to be the most accurate diagnostic tool in the analysis of brain metastasis than any other classical methods. The authors studied CT findings of intracranial metastasis in 31 cases proven clinically and histologically. The results were as follows: 1. Age distribution of the cases was 15 males and 16 females with peak age of 6th decade in males and 4th decade in female. 2. Metastic lesions were multiple in 18 cases and single in 13 cases. 3. The most common degree of edema was grade III, 43% of total metastatic foci. Marked edematous low densities with relatively small nodular high densities in precontrast scan and variable contrast enhancement of the nodular densities were the most frequent CT findings. 4. No specific characteristics according to the primary cancer was noted. All four cases of choriocarcinoma showed hemorrhagic tendency.

  20. Computed tomographic findings of neonatal intraventricular hemorrhage

    Intraventricular hemorrhage frequently occurs in premature newborn infants, and the prognosis is usually poor. Recently, with new methods for computed tomography (CT) and ultrasonic tomography, the size of the hematoma and the degree of ventricular dilatation can be determined allowing early therapeutic management of this disease. Papile et al. (1980) classified subependymal and intraventricular hemorrhage in premature infants into four types, and reported the prognosis, especially the incidence of hydrocephalus for each type. Since the report of Goldstein et al. (1976), early treatment with repeated lumbar punctures (RLP) have been tried at several institutions. A few reports evaluating this treatment have been published. In this paper the features of CT in eighteen surviving infants with intraventricular hemorrhage are described. Early clinical management of the hemorrhage with repeated lumbar punctures is evaluated. (author)

  1. Lymphadenopathy in celiac disease: computed tomographic observations

    Jones, B.; Bayless, T.M.; Fishman, E.K.; Siegelman, S.S.

    1984-06-01

    Lymphadenopathy in patients with celiac disease is generally viewed with alarm due to the association between celiac disease and intestinal lymphoma. Four patients with celiac disease are described in whom significant mesenteric and paraaortic adenopathy was demonstrated by computed tomogrophy (CT). The subsequent clinical course of these patients revealed no evidence of lymphoma. In two patients with longstanding celiac disease and recent relapse, exploratory laparotomy revealed reactive hyperplasia in the enlarged glands; in one patient this was associated with intestinal ulceration, and in the other no underlying pathology was found. Follow-up CT scans in both these patients demonstrated regression of the findings with clinical improvement. In the other two patients, CT was performed as part of the initial evaluation.

  2. Computed tomographic analysis of renal calculi

    Hillman, B.J.; Drach, G.W.; Tracey, P.; Gaines, J.A.

    1984-03-01

    An in vitro study sought to determine the feasibility of using computed tomography (CT) to analyze the chemical composition of renal calculi and thus aid in selecting the best treatment method. Sixty-three coded calculi were scanned in a water bath. Region-of-interest measurements provided the mean, standard deviation, and minimum and maximum pixel values for each stone. These parameters were correlated with aspects of the stones' chemical composition. A multivariate analysis showed that the mean and standard deviation of the stones' pixel values were the best CT parameters for differentiating types of renal calculi. By using computerized mapping techniques, uric acid calculi could be perfectly differentiated from struvite and calcium oxalate calculi. The latter two types also were differentiable, but to a lesser extent. CT has a potential role as an adjunct to clinical and laboratory methods for determining the chemical composition of renal calculi in an effort to select optimal treatment.

  3. Computed tomographic analysis of renal calculi

    An in vitro study sought to determine the feasibility of using computed tomography (CT) to analyze the chemical composition of renal calculi and thus aid in selecting the best treatment method. Sixty-three coded calculi were scanned in a water bath. Region-of-interest measurements provided the mean, standard deviation, and minimum and maximum pixel values for each stone. These parameters were correlated with aspects of the stones' chemical composition. A multivariate analysis showed that the mean and standard deviation of the stones' pixel values were the best CT parameters for differentiating types of renal calculi. By using computerized mapping techniques, uric acid calculi could be perfectly differentiated from struvite and calcium oxalate calculi. The latter two types also were differentiable, but to a lesser extent. CT has a potential role as an adjunct to clinical and laboratory methods for determining the chemical composition of renal calculi in an effort to select optimal treatment

  4. Computed tomographic evaluation of the pancreas

    Analysis of the clinical experience in the evaluation of the pancreas with computed tomography (CT) since October 1975 indicates that it is a reliable, often specific and relatively noninvasive method for the detection of pancreatic neoplasms and the varied manifestations of pancreatitis and its complications. The normal pancreas is clearly imaged in all but the leanest or uncooperative patients. Tumors of pancreas are identified as focal alteration in the size or contour of the gland. Obliteration of contiguous fat planes, areas of necrosis within the tumor, and secondary effects on the uninvolved parts of the pancreas and biliary tree can be identified. CBT has substantially reduced the need for pancreatic angiography, percutaneous transhepatic cholangiography, and endoscopic retrograde pancreatocholangiography at this medical center. Although a definitive comparison of ultrasound and CT has not yet been accomplished, initial experience indicates that a complementary rather than competitive relationship will develop between the two imaging methods. (orig.) 891 MG/orig. 892 MB

  5. Computed tomographic finding of tuberous sclerosis

    Computed tomography has been established as a useful imaging method in the diagnosis of tuberous sclerosis. By demonstrating the characteristic intracranial lesion, it allows confirmation of the diagnosis and provides a noninvasive means of evaluating the patient with seizure and mental retardation. Authors analysed CT findings in 20 cases of tuberous sclerosis since March 1985 through August 1988. The results were as follows: 1) There are 14 men and 6 women with the age raging from 6 months to 45 years. 2) Ventricular calcified tubers are noted at the frontal horn (16/20, 80%), body (13/20, 65%), atrium (9/20 45%) of the lateral ventricles. 1 case shows the haematuria near the foramen of Monro. 3) In the cortical region, 1 case of high density tuber and 2 cases of focal atrophy are noted. 4) In the white mater, 3 cases of amorphous calcifications and 1 case of demyelinating hypodensity are seen.

  6. COMPUTER AIDED DESIGN IN URBAN ARHITECTURE 3D MODELING

    Nicolae Radu MARSANU; Silvia Mihaela RUSU

    2010-01-01

    The gap from the PC made sketches with the help of the china ink pen and ruler to the digitised drawing boards, high diagonal monitors and 3D projecting is truly spectacular. The increasingly efficient and more specialized programs allow the architects a whole range of facilities providing drawing commands and changes very easy to use, automatic rating, operating simultaneously in multiple windows, building sections and extracts of the plan, 3D views design and even projecting in virtual real...

  7. Automatic Plant Annotation Using 3D Computer Vision

    Nielsen, Michael

    In this thesis 3D reconstruction was investigated for application in precision agriculture where previous work focused on low resolution index maps where each pixel represents an area in the field and the index represents an overall crop status in that area. 3D reconstructions of plants would all...... machinery or a field robot or a self guided tractor following a sample strategy based on overview maps of the field....

  8. 3D Printing device adaptable to Computer Numerical Control (CNC)

    Gardan, Julien; DANESI, Frédéric; Roucoules, Lionel; Schneider, A

    2014-01-01

    This article presents the development of a 3D printing device for the additive manufacturing adapted to a CNC machining. The application involves the integration of a specific printing head. Additive manufacturing technology is most commonly used for modeling, prototyping, tooling through an exclusive machine or 3D printer. A global review and analysis of technologies show the additive manufacturing presents little independent solutions [6][9]. The problem studied especially the additive manu...

  9. Computer Aided Interpretation Approach for Optical Tomographic Images

    Klose, Christian D; Netz, Uwe; Beuthan, Juergen; Hielscher, Andreas H

    2010-01-01

    A computer-aided interpretation approach is proposed to detect rheumatic arthritis (RA) of human finger joints in optical tomographic images. The image interpretation method employs a multi-variate signal detection analysis aided by a machine learning classification algorithm, called Self-Organizing Mapping (SOM). Unlike in previous studies, this allows for combining multiple physical image parameters, such as minimum and maximum values of the absorption coefficient for identifying affected and not affected joints. Classification performances obtained by the proposed method were evaluated in terms of sensitivity, specificity, Youden index, and mutual information. Different methods (i.e., clinical diagnostics, ultrasound imaging, magnet resonance imaging and inspection of optical tomographic images), were used as "ground truth"-benchmarks to determine the performance of image interpretations. Using data from 100 finger joints, findings suggest that some parameter combinations lead to higher sensitivities while...

  10. Computed tomographic features of the adrenal glands

    Conventional radiography of the adrenal glands are too often unsatisfactory. It is well known that the whole body computed tomography is very useful in identifying retroperitoneal pathology. The authors intended to present normal data of adrenal glands for preparation of basis for interpretation of abnormalities. We reviewed CT scans of 30 cases without evidence of adrenal disease and 4 cases of adrenal lesions. The results are as follows: 1. There were 16 male and 14 female patients, and their ages ranged from 10 to 70 years. 2. On CT, both glands were shown in 23 (76%), the right in 24 (80%) and the left in 26 (86%). 3. Most of the right adrenal gland was linear or comet in shape in the apex, and partly 'inverted V' in the base. 4. The right adrenal had length of 2.4 ± 0.8 cm, width of 2.6 ± 0.8 cm and thickness of 0.6 ± 0.1 cm. The left adrenal, 2.5 ± 0.7 cm, 2.4 ± 0.5 cm and 0.7 ± 0.1 cm respectively. 5. In 2 cases of Cushing's syndrome, CT demonstrated grossly enlarged, smooth-contoured adrenal glands with convex borders. 6. In the case of cortical adenoma, CT showed the mass of homogeneous low density as a result to high total fat content.7. In pheochromocytoma, CT showed relatively large mass with low density.

  11. Computed tomographic study on Mycoplasma pneumoniae pneumonia

    Serologically proven 21 patients with Mycoplasma pneumoniae pneumonia that showed infiltrative shadows on chest radiograms were studied by computed tomography (CT). Localization of the lesion and the fashion of its progression through the lung were analyzed. Following 3 loci were defined on the basis of the investigations of critical analysis of the chest radiograms, and of radiopathological analysis of the experimental animal model of mycoplasmal pneumonia with soft X-ray image. I: Peribronchial and periarterial interstitium. II: Bronchiole and its surroundings. III: Lung parenchyma, on hilar area as IIIh, on marginal area as IIIm. Even in the early phase of this disease, radiopathological findings on CT have been distributed in all loci mentioned above. The Shadow disappeared from locus III approximately 14th day from the onset. The shadow have remained, however, loci I, II for a long period. Those findings suggest that locus I and II are one of the major focus of Mycoplasma neumoniae pneumonia. Volume loss in the locus III was observed 78 % of the cases at 28th day from the onset. The shadow on locus IIIh was more prominent than locus IIIm. Reported analytical method with CT could be widely applied to disclose a radiopathological details in other infectious diseases of the lung. (author)

  12. Computer diagnosis of tomographic pulmonary images

    This dissertation records an attempt to construct empirically a robust algorithm capable of differentiating between images of healthy and abnormal lung parenchyma. The aim is to provide the basis for computer software that will facilitate the automatic diagnosis of pulmonary disease. Six archived data sets, comprising images of a range of known physiological conditions, are used to inform the final diagnostic algorithm. However, irregularities common in such data - arising from factors associated with scanning protocols and image reconstruction - demand that some consistent means of normalizing the images be adopted. Lung morphology results in the fractal structure of the broncho-vascular tree, which provides an efficient network for transporting air and blood to the alveoli and accounts for the homogeneous density of the lung parenchyma. Local density is decreased by lesions occurring as residual air pockets beyond the terminal bronchioles, and increased by fibrous scarring. The result is darker or lighter greyscale levels in the corresponding images. The sensitivity of CT to parenchymal density changes makes such deviations from 'normal' greyscale values good indices of disease. However, as the aforementioned conditions are often present together, average density cannot be used as a discriminator, so a set of three 'panning' threshold windows are prepared: one to 'see' only a range of darker pixels, another the 'normal' ones, the third the unnaturally light ones. Different features can thus be segmented and quantified. An image 'feature' here implies a subset of a significant number of adjacent, thresholded pixels. Its 'space-filling' character is assessed by assigning it a fractal dimension. The number and greyscale range of the pixels comprising the pattern (feature) together with its assessed fractal dimension are used as diagnostic indices. As a conclusion to the diagnostic exercise, some aspects of image processing are suggested as useful in addressing the

  13. A computed tomographic study on epilepsy

    140 patients with epileptic seizure were studied by computed tomography during the period from Feb. 1979 to Aug. 1979 in the Department or Radiology, College of Medicine, Hangyang University. Those findings on CT and clinical records including EEG findings were reviewed. The results were as follows: 1. Age distribution of the total 140 patients was broad ranging from 1 month to 63 years. 73.5% of patients was below the age of 30. The patient population was comprised of 93 males and 47 females, and its male to female ratio was 2 : 1. 2. The type of epileptic seizure were classified according to the International League against Epilepsy. 42.9% of patients had primary generalized seizure, 47.1% with partial seizure, and 10% with non classifiable seizure. 3. As additional symptoms and signs except seizure, headache was most common, and the next was nausea and vomiting. Uncommonly, there were also insomnia, personality change, and memory disturbance. 4. 37.1% of patients had less than 1 month of seizure history, 19.3% between 1 year and 5 years. 5. EEG findings were available in 41 patients, and normal in 15 cases. 26 patients revealed abnormal findings. Among those abnormal findings focal slowing was appeared in 19.5% and generalized slowing in 17.1%. 6. 52% of patients showed abnormal findings on CT. The most common abnormal findings was focal low density (30%), and the next was diffuse hydrocephalus (7.1%). After contrast infusion, contrast enhancement was occurred in cases with focal low density, focal high or isodense mass density. In patients with focal low density, ring or nodular enhancement were common, and diffuse or serpentime enhancement in focal high or isodence mass density. 7. The frequency of structural abnormalities on CT was more common in patients below the age of 10 and over 30 than other age groups. The epilepsy starting below 10 and over 30 years of age showed structural abnormalities in 63.6-100%. 8. The patients who had less than 6 months of

  14. From Digital to Physical: Computational Aspects of 3D Manufacturing

    Baecher, Moritz Niklaus

    2013-01-01

    The desktop publishing revolution of the 1980s is currently repeating itself in 3D, referred to as desktop manufacturing. Online services such as Shapeways have become available, making personalized manufacturing on cutting edge additive manufacturing (AM) technologies accessible to a broad audience. Affordable desktop printers will soon take over, enabling people to fabricate

  15. Software-based geometry operations for 3D computer graphics

    Sima, M.; Iancu, D.; Glossner, J.; Schulte, M.; Mamidi, S.

    2006-01-01

    In order to support a broad dynamic range and a high degree of precision, many of 3D renderings fundamental algorithms have been traditionally performed in floating-point. However, fixed-point data representation is preferable over floatingpoint representation in graphics applications on embedded de

  16. Detecting and visualizing internal 3D oleoresin in agarwood by means of micro-computed tomography

    Detection and analysis of oleoresin is particularly significant since the commercial value of agarwood is related to the quantity of oleoresins that are present. A modern technique of non-destructive may reach the interior region of the wood. Currently, tomographic image data in particular is most commonly visualized in three dimensions using volume rendering. The aim of this paper is to explore the potential of high resolution non-destructive 3D visualization technique, X-ray micro-computed tomography, as imaging tools to visualize micro-structure oleoresin in agarwood. Investigations involving desktop X-ray micro-tomography system on high grade agarwood sample, performed at the Centre of Tomography in Nuclear Malaysia, demonstrate the applicability of the method. Prior to experiments, a reference test was conducted to stimulate the attenuation of oleoresin in agarwood. Based on the experiment results, micro-CT imaging with voxel size 7.0 μm is capable to of detecting oleoresin and pores in agarwood. This imaging technique, although sophisticated can be used for standard development especially in grading of agarwood for commercial activities. (author)

  17. Three-dimensional multislice spiral computed tomographic angiography: a potentially useful tool for safer free tissue transfer to complicated regions

    Demirtas, Yener; Cifci, Mehmet; Kelahmetoglu, Osman;

    2009-01-01

    Three-dimensional multislice spiral computed tomographic angiography (3D-MSCTA) is a minimally invasive method of vascular mapping. The aim of this study was to evaluate the clinical usefulness of this imaging technique in delineating the recipient vessels for safer free tissue transfer to...... kept in mind, especially inthe patients with peripheral vascular disease. 3D-MSCTA has the potential to replace digital subtraction angiography for planning of microvascular reconstructions and newer devices with higher resolutions will probably increase the reliability of this technique. (c) 2009...

  18. Pineal region tumors: computed tomographic-pathologic spectrum

    Futrell, N.N.; Osborn, A.G.; Cheson. B.D.

    1981-11-01

    While several computed tomographic (CT) studies of posterior third ventricular neoplasms have included descriptions of pineal tumors, few reports have concentrated on these uncommon lesions. Some authors have asserted that the CT appearance of many pineal tumors is virtually pathognomonic. A series of nine biopsy-proved pineal gland and eight other presumed tumors is presented that illustrates their remarkable heterogeneity in both histopathologic and CT appearance. These tumors included germinomas, teratocarcinomas, hamartomas, and other varieties. They had variable margination, attentuation, calcification, and suprasellar extension. Germinomas have the best response to radiation therapy. Biopsy of pineal region tumors is now feasible and is recommended for treatment planning.

  19. Computed tomographical imaging of the brain in post hypoglycemic coma

    Iwai, A.; Sakamoto, T.; Kinoshita, Y.; Yokota, J.I.; Yoshioka, T.; Sugimoto, T.

    1987-07-01

    A case of post severe hypoglycemic coma was studied by sequential Computed Tomographic Imaging (CT) of the brain. The CT 1) was normal in the early stage, 2) subsequently showed a low density area, which was enhanced by the contrast medium, in the cerebral cortex and the boundary zone between the major cerebral arteries, and 3) revealed marked enhancement in the entire cortical region and hypodensity in the periventricular region in the late stage. These CT findings, representing the course of neural cell damage by severe hypoglycemia, are discussed from the pathophysiological viewpoint.

  20. Computed tomographical imaging of the brain in post hypoglycemic coma

    A case of post severe hypoglycemic coma was studied by sequential Computed Tomographic Imaging (CT) of the brain. The CT 1) was normal in the early stage, 2) subsequently showed a low density area, which was enhanced by the contrast medium, in the cerebral cortex and the boundary zone between the major cerebral arteries, and 3) revealed marked enhancement in the entire cortical region and hypodensity in the periventricular region in the late stage. These CT findings, representing the course of neural cell damage by severe hypoglycemia, are discussed from the pathophysiological viewpoint. (orig.)

  1. Weight prediction of broiler chickens using 3D computer vision

    Mortensen, Anders Krogh; Lisouski, Pavel; Ahrendt, Peter

    2016-01-01

    employed. The camera was robust to the changing light conditions of the broiler house as it contained its own infrared light source. A newly developed image processing algorithm is proposed. The algorithm first segmented the image with a range-based watershed algorithm, then extracted twelve different...... a platform weigher which may also include ill birds. In the current study, a fully-automatic 3D camera-based weighing system for broilers have been developed and evaluated in a commercial production environment. Specifically, a low-cost 3D camera (Kinect) that directly returned a depth image was...... period. A traditional platform weigher was used to estimate the reference weights. An average relative mean error of 7.8% between the predicted weights and the reference weights is achieved on a separate test set with 83 broilers in approximately 13,000 manually annotated images. The errors were...

  2. Learning Projectile Motion with the Computer Game ``Scorched 3D``

    Jurcevic, John S.

    2008-01-01

    For most of our students, video games are a normal part of their lives. We should take advantage of this medium to teach physics in a manner that is engrossing for our students. In particular, modern video games incorporate accurate physics in their game engines, and they allow us to visualize the physics through flashy and captivating graphics. I recently used the game "Scorched 3D" to help my students understand projectile motion.

  3. Coupling of the computational fluid dynamics code ANSYS CFX with the 3D neutron kinetic core model DYN3D

    The computational fluid dynamics code ANSYS CFX has been coupled with the neutron-kinetic core model DYN3D. ANSYS CFX calculates the fluid dynamics and related transport phenomena in the reactors coolant and provides the corresponding data to DYN3D. In the fluid flow simulation of the coolant, the core itself is modeled within the porous body approach. DYN3D calculates the neutron kinetics and the fuel behavior including the heat transfer to the coolant. The physical data interface between the codes is the volumetric heat release rate into the coolant. In the prototype that is currently available, the coupling is restricted to single-phase flow problems. In the time domain an explicit coupling of the codes has been implemented so far. Steady-state and transient verification calculations for two small-size test problems confirm the correctness of the implementation of the prototype coupling. The first test problem was a mini-core consisting of nine real-size fuel assemblies with quadratic cross section. Comparison was performed with the DYN3D stand-alone code. In the steady state, the effective multiplication factor obtained by the DYN3D/ANSYS CFX codes hows a deviation of 9.8 pcm from the DYN3D stand-alone solution. This difference can be attributed to the use of different water property packages in the two codes. The transient test case simulated the withdrawal of the control rod from the central fuel assembly at hot zero power in the same mini-core. Power increase during the introduction of positive reactivity and power reduction due to fuel temperature increase are calculated in the same manner by the coupled and the stand-alone codes. The maximum values reached during the power rise differ by about 1 MW at a power level of 50 MW. Beside the different water property packages, these differences are caused by the use of different flow solvers. The same calculations were carried for a mini-core with seven real-size fuel assemblies with hexagonal cross section in

  4. Method for determination of size and the anatomic shape of autogenic bone transplant according to 3D computer images of the cranium

    The repair of great mandibular defects is still a real problem in the maxillo-facial surgery. During the treatment planning we use very often only two-dimensional radiographic images and cefalometric analysis. Their possibility to measure three-dimensionally is limited. On the base of 3D-images, created by computer-tomographical SSD - technique, we present a new method to justify the size and anatomical form of the autogenous transplants during mandibular reconstruction

  5. Computed tomographic features of fibrous dysplasia of maxillofacial region

    Sontakke, Subodh Arun; Karjodka, Freny R [Nair Hospital Dental College, Mumba (India); Umarji, Hemant R [Government Dental College and Hospital, Mumbai (India)

    2011-03-15

    This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibrous dysplasia was confirmed by histopathological report. All cases showed the ill-defined margins of lesions except in the region where the lesions were extending to cortex of the involved bone. Internal structure of all cases showed ground glass appearance. Four cases of maxillary lesion showed the displacement of maxillary sinus maintaining the shape of maxillary sinus. Two cases showed complete obliteration of maxillary sinus. Displacement of inferior alveolar canal did not follow any typical pattern in any of the cases but was displaced in different directions. The craniofacial type of fibrous dysplasia is as common as fibrous dysplasia of jaw. The margins, extent, internal structure and effect on surrounding structure are well detected on computed tomographic images.

  6. Handling Missing Data in the Computation of 3D Affine Transformations

    Martisson, Hanna; Bartoli, Adrien; Gaspard, François; Lavest, Jean-Marc

    2005-01-01

    The reconstruction of rigid scenes from multiple images is a central topic in computer vision. Approaches merging partial 3D models in a hierarchical manner have proven the most eective to deal with large image sequences. One of the key building blocks of these hierarchical approaches is the alignment of two partial 3D models, which requires to express them in the same 3D coordinate frame by computing a 3D transformation. This problem has been well-studied for the cases of 3D models obtained ...

  7. Shadow of a Colossus: A z=2.45 Galaxy Protocluster Detected in 3D Ly-a Forest Tomographic Mapping of the COSMOS Field

    Lee, Khee-Gan; White, Martin; Prochaska, J Xavier; Font-Ribera, Andreu; Schlegel, David J; Rich, R Michael; Suzuki, Nao; Stark, Casey W; Fevre, Olivier Le; Nugent, Peter E; Salvato, Mara; Zamorani, Gianni

    2015-01-01

    Using moderate-resolution optical spectra from 58 background Lyman-break galaxies and quasars at $z\\sim 2.3-3$ within a $11.5'\\times13.5'$ area of the COSMOS field ($\\sim 1200\\,\\mathrm{deg}^2$ projected area density or $\\sim 2.4\\,h^{-1}\\,\\mathrm{Mpc}$ mean transverse separation), we reconstruct a 3D tomographic map of the foreground Ly$\\alpha$ forest absorption at $2.23d}\\approx3.5\\,h^{-1}\\,\\mathrm{Mpc}$ comoving. Comparing with 61 coeval galaxies with spectroscopic redshifts in the same volume, we find that the galaxy positions are clearly biased towards regions with enhanced IGM absorption in the tomographic map. We find an extended IGM overdensity with deep absorption troughs at $z=2.45$ associated with a recently-discovered galaxy protocluster at the same redshift. Based on simulations matched to our data, we estimate the enclosed dark matter mass within this IGM overdensity to be $M_{\\rm dm} (z=2.45) = (9\\pm4)\\times 10^{13}\\,h^{-1}\\,\\mathrm{M_\\o...

  8. Computed tomographic evaluation of pancreatic and peripancreatic cystic mass

    Forty-four cases of pancreatic cystic mass (pancreatic pseudocyst 37, pseudocyst caused by pancreatic carcinoma 2, mucous producing caner 2, cystadenoma 1, cystadenocarcinoma 2, and 16 cases of peripancreatic cystic mass (intestinal leiomyosarcoma 10, lymphonode metastasis 3, mesenteric hematoma 1, carcinoma of Vater's papilla 1, duplicating cyst of duodenum 1) were evaluated by computed tomography during the period from April 1978 to December 1984 at Fujita-Gakuen Health University Hospital. The most common cystic masses of pancreatic and peripancreatic lesion were pseudocyst. Although there are many cystic masses mimicking a pancreatic pseudocyst in pancreatic region, sometimes it is impossible to distinguish between cystic mass arising in the pancreas and the adjuvant organ. Difficulties in the computed tomographic differential diagnosis between pancreatic and peripancreatic cystic mass are analyzed and discussed in this paper. (author)

  9. Spontaneous Intracerebral Hemorrhage: Computed Tomographic Characteristics and Outcome

    Aimara de la Caridad Vergara Sánchez

    2015-12-01

    Full Text Available Background: strokes are the third leading cause of death among adults and 10-15 % of them are due to spontaneous intracerebral hemorrhage. Objective: to characterize spontaneous intracerebral hemorrhage through computed tomography scan and its outcome. Methods: a case series study was conducted comprising patients diagnosed with spontaneous intracerebral hemorrhage admitted to the Arnaldo Milián Castro Provincial University Hospital in Villa Clara from January 2009 to January 2010. Tomographic variables of interest were derived from evaluation of spontaneous intracerebral hematomas. Results: fifty-nine cases of spontaneous intracerebral hemorrhage were studied, 23 were located in lobar regions, 4 had severe midline shift, and 2 showed volume greater than 80 ml. Eight out of eleven with extension into the ventricular system had an unfavorable outcome. Among those with thalamic hemorrhage, patients with diameter larger than 4cm and extension into the ventricular system died. Patients with putaminal hemorrhage larger than 4 cm and posterior fossa hematoma with hydrocephalus had a poor outcome, as well as most individuals (55 with other mass effects. Most lobar hematomas (14 out of 23 had a satisfactory outcome, unlike cerebellar and brainstem hematomas. Conclusions: tomographic variables that had a negative impact on the outcome were: volume greater than 80 ml, severe midline shift, diameter larger than 4 cm, extension into the ventricular system, hydrocephalus, other signs of mass effect and brainstem location.

  10. Simulation on 3D acoustic fields on a concurrent computer

    1996-01-01

    In this paper. we present a method used to calculate the acoustic field created by a transducer. A parallel computer network was used to elaborate the effectiveness of the direct calculation of the Rayleigh Integral.

  11. The 3d International Workshop on Computational Electronics

    Goodnick, Stephen M.

    1994-09-01

    The Third International Workshop on Computational Electronics (IWCE) was held at the Benson Hotel in downtown Portland, Oregon, on May 18, 19, and 20, 1994. The workshop was devoted to a broad range of topics in computational electronics related to the simulation of electronic transport in semiconductors and semiconductor devices, particularly those which use large computational resources. The workshop was supported by the National Science Foundation (NSF), the Office of Naval Research and the Army Research Office, as well as local support from the Oregon Joint Graduate Schools of Engineering and the Oregon Center for Advanced Technology Education. There were over 100 participants in the Portland workshop, of which more than one quarter represented research groups outside of the United States from Austria, Canada, France, Germany, Italy, Japan, Switzerland, and the United Kingdom. There were a total 81 papers presented at the workshop, 9 invited talks, 26 oral presentations and 46 poster presentations. The emphasis of the contributions reflected the interdisciplinary nature of computational electronics with researchers from the Chemistry, Computer Science, Mathematics, Engineering, and Physics communities participating in the workshop.

  12. Efficient ray tracing on 3D regular grids for fast generation of digitally reconstructed radiographs in iterative tomographic reconstruction techniques

    Dittmann, Jonas

    2016-01-01

    Cone beam projection is an essential and particularly time consuming part of any iterative tomographic reconstruction algorithm. On current graphics hardware especially the amount and pattern of memory accesses is a limiting factor when read-only textures cannot be used. With the final objective of accelerating iterative reconstruction techniques, a non-oversampling Joseph-like raytracing projection algorithm for three dimensions featuring both a branchless sampling loop and a cache friendly memory access pattern is presented. An interpretation of the employed interpolation scheme is given with respect to the effective beam and voxel models implied. The method is further compared to existing techniques, and the modifications required to implement further voxel and beam shape models are outlined. Both memory access rates and total run time are benchmarked on a current consumer grade graphics processing unit and explicitly compared to the performance of a classic Digital Differential Analyzer (DDA) algorithm. T...

  13. Computational 3-D Model of the Human Respiratory System

    We are developing a comprehensive, morphologically-realistic computational model of the human respiratory system that can be used to study the inhalation, deposition, and clearance of contaminants, while being adaptable for age, race, gender, and health/disease status. The model ...

  14. Study on diagnosis of peritoneal metastases with computed tomographic peritoneography

    Objective: To investigate the diagnostic value and clinical significance of computed tomographic peritoneography (CTP) for peritoneal metastases. methods: Twenty-five cases with peritoneal metastases examined by plain CT and CTP with complete clinical information and surgical-pathologic results were retrospectively analyzed and correlative study was done in 20 cases. Results: The sensitivity of plain CT and CTP for detection of peritoneal metastases at all sites of involvement was 47.5% and 76.8%, respectively (x2 = 16.92, P < 0.005). For CTP, the highest sensitivity was in the bilateral sub-phrenic space (88.0%) and para-colic gutter (74.0%). conclusion: CTP is an effective imaging modality in detecting and diagnosing peritoneal metastases superior to plain CT

  15. Low-dose computed tomographic imaging in orbital trauma

    The authors review findings in 75 computed tomographic (CT) examinations of 66 patients with orbital trauma who were imaged using a low-radiation-dose CT technique. Imaging was performed using a dynamic scan mode and exposure factors of 120 kVp and 80 mAs resulting in a skin dose of 11 mGy with an effective dose-equivalent of 0.22 mSv. Image quality was diagnostic in all cases and excellent in 73 examinations. Soft-tissue abnormalities within the orbit including muscle adhesions were well demonstrated both on primary axial and reconstructed multiplanar images. The benefits of multiplanar reconstructions are stressed and the contribution of soft-tissue injuries to symptomatic diplopia examined. (author)

  16. Computed tomographic evaluation of gallstone calcification for biliary lithotripsy.

    Caslowitz, P L; Fishman, E K; Kafonek, D R; Lillemoe, K D; Mitchell, S; Widlus, D M; Saba, G P

    1991-04-01

    As the Food and Drug Administration trials for biliary lithotripsy in the United States near completion, future criteria for patient eligibility remain to be defined. Gallstone calcification greater than 3-mm partial rim on plain film (KUB) or oral cholecystogram (OCG) has excluded patients thus far, since early results of gallstone clearance (lithotripsy plus chemodissolution) were suboptimal with calcified stones. To evaluate the usefulness of these criteria for gallstone fragmentation, computed tomographic (CT) scans were performed on 20 patients immediately prior to lithotripsy to evaluate gallstone density and 24 hours after lithotripsy to observe the CT appearance of fragmentation. The adequacy of fragmentation was determined by pre- and post-lithotripsy sonography. This report constitutes the results of these investigations. PMID:10149158

  17. An Algorithm for Fast Computation of 3D Zernike Moments for Volumetric Images

    Khalid M. Hosny; Hafez, Mohamed A.

    2012-01-01

    An algorithm was proposed for very fast and low-complexity computation of three-dimensional Zernike moments. The 3D Zernike moments were expressed in terms of exact 3D geometric moments where the later are computed exactly through the mathematical integration of the monomial terms over the digital image/object voxels. A new symmetry-based method was proposed to compute 3D Zernike moments with 87% reduction in the computational complexity. A fast 1D cascade algorithm was also employed to add m...

  18. Computational 3D and reflectivity imaging with high photon efficiency

    Shin, Dongeek; Kirmani, Ahmed; Shapiro, Jeffrey H.; Goyal, Vivek K

    2014-01-01

    Capturing depth and reflectivity images at low light levels from active illumination of a scene has wide-ranging applications. Conventionally, even with single-photon detectors, hundreds of photon detections are needed at each pixel to mitigate Poisson noise. We introduce a robust method for estimating depth and reflectivity using on the order of 1 detected photon per pixel averaged over the scene. Our computational imager combines physically accurate single-photon counting statistics with ex...

  19. 3D Imaging of Buried Dielectric Targets with a Tomographic Microwave Approach Applied to GPR Synthetic Data

    Alessandro Galli; Davide Comite; Ilaria Catapano; Gianluca Gennarelli; Francesco Soldovieri; Elena Pettinelli

    2013-01-01

    Effective diagnostics with ground penetrating radar (GPR) is strongly dependent on the amount and quality of available data as well as on the efficiency of the adopted imaging procedure. In this frame, the aim of the present work is to investigate the capability of a typical GPR system placed at a ground interface to derive three-dimensional (3D) information on the features of buried dielectric targets (location, dimension, and shape). The scatterers can have size comparable to the resolution...

  20. 3D neutron computed tomography. Requirements and applications

    Other than X-rays, neutrons can penetrate most metals easily while delivering a high contrast for many light-weight elements. Especially their high sensitivity for hydrogen makes them a valuable tool for the detection of organic materials like lubricants, plastics or sealants within metal housings. Neutron radiography and tomography complement the application of X-ray for the inspection of complex and critical components like in automotive and aerospace applications. An overview about the technical and mathematical differences between neutron and X-ray tomography is given and the imperfections and limitations of a neutron setup are shown. Several examples of technical neutron computed tomography are given. (author)

  1. Computation of Electrostatic Properties of 3D MEMS Structures

    Majumdar, N

    2006-01-01

    Micro-Electro-Mechanical Systems (MEMS) normally have fixed or moving structures with cross-sections of the order of microns ($\\mu m$) and lengths of the order of tens or hundreds of microns. These structures are often plates or array of thin beams which, owing to their smallness, can be moved or deflected easily through the application of low voltages. Since electrostatic forces play a very major role in maneuvering these devices, a thorough understanding of the electrostatic properties of these structures is of critical importance, especially in the design phase of MEMS. In many cases, the electrostatic analysis of MEMS is carried out using boundary element method (BEM), while the structural analysis is carried out using finite element method (FEM). In this paper, we focus on accurate electrostatic analysis of MEMS using BEM. In particular, we consider the problem of computing the charge distribution and capacitance of thin conducting plates relevant to the numerical simulation of MEMS. The reason behind th...

  2. Exceptionally preserved Cambrian trilobite digestive system revealed in 3D by synchrotron-radiation X-ray tomographic microscopy.

    Mats E Eriksson

    Full Text Available The Cambrian 'Orsten' fauna comprises exceptionally preserved and phosphatised microscopic arthropods. The external morphology of these fossils is well known, but their internal soft-tissue anatomy has remained virtually unknown. Here, we report the first non-biomineralised tissues from a juvenile polymerid trilobite, represented by digestive structures, glands, and connective strands harboured in a hypostome from the Swedish 'Orsten' fauna. Synchrotron-radiation X-ray tomographic microscopy enabled three-dimensional internal recordings at sub-micrometre resolution. The specimen provides the first unambiguous evidence for a J-shaped anterior gut and the presence of a crop with a constricted alimentary tract in the Trilobita. Moreover, the gut is Y-shaped in cross section, probably due to a collapsed lumen of that shape, another feature which has not previously been observed in trilobites. The combination of anatomical features suggests that the trilobite hypostome is functionally analogous to the labrum of euarthropods and that it was a sophisticated element closely integrated with the digestive system. This study also briefly addresses the preservational bias of the 'Orsten' fauna, particularly the near-absence of polymerid trilobites, and the taphonomy of the soft-tissue-harbouring hypostome.

  3. The effect of activity outside the direct field of view in a 3D-only whole-body positron tomograph

    The ECAT EXACT3D (CTI/Siemens 966) 3D-only PET tomograph has unprecedented sensitivity due to the large BGO (bismuth germanate) detector volume. However, the consequences of a large (23.4 cm) axial field-of-view (FOV) and the need for a patient port diameter to accommodate body scanning make the device more sensitive to photons arising from activity outside the direct (coincidence) FOV. This leads to relatively higher deadtime and an increased registration of random and scatter (true) coincidences. The purpose of this study is to determine the influence of activity outside the FOV on (i) noise-equivalent counts (NEC) and (ii) the performance of a 'model-based' scatter correction algorithm, and to investigate the effect of side shielding additional to that supplied with the tomograph. Annular shielding designed for brain scanning increased the NEC for blood flow (H215O) measurement (integrated over 120 s) by up to 25%. For 11C tracer studies, the increase is less than 5% over 120 min. Purpose-built additional body shielding, made to conform to the shape of a volunteer, reduced the randoms count rate in a heart blood flow measurement (H215O) by about 30%. After scatter correction the discrepancy between ROI count ratios for compartments within the 20 cm diameter 'Utah' phantom differed by less than 5% from true (sampled) activity concentration ratios. This was so with or without activity outside the FOV and with or without additional side shielding. Count rate performance is thus improved by extra shielding but more improvement is seen in head than in body scanning. Measurement of heart blood flow using bolus injections of H215O would benefit from the use of detectors with lower deadtime and superior timing resolution such as LSO (lutetium oxyorthosilicate). (author)

  4. 3D dosimetry for complex stereotactic radiosurgery using a tomographic optical density scanner and BANG polymer gels

    Purpose: Radiation sensitive tissue equivalent BANG polymer gels (MGS Research, Inc., Guilford, CT) have been developed for three dimensional verification of complex radiotherapy treatment plans. This study evaluated the performance of a prototype optical density scanner in verification of a complex radiosurgery treatment plan using linear accelerator based radiosurgery and BANG polymer gel dosimeters. Materials and Methods: BANG polymer gel dosimeters were treated with stereotactic radiosurgery using 6MV photons to single isocenters and to a 3 isocenter radiosurgery plan. Appropriate controls for evaluating the linearity of dose response were irradiated using a water bath and 6MV photons. Two separate methods for imaging the radiation-induced polymerization in the gel were used. The first method, MRI imaging, used the spatial distribution of the NMR transverse relaxation rates (R2) of the water protons in the gel to create a 3D dose map. In the second, a prototype optical density scanner was used to reconstruct a 3D dose distribution from multiple planar images of the gel which were generated using a filtered back-projection algorithm and measurements of optical transmission. Results: Data obtained from MRI imaging and the images generated by the optical scanner were compared with the plan with excellent results. Very close agreement between all three data sets was demonstrated. The BANG polymer gels demonstrated an excellent linearity of response and a very large (∼20 Gray) dynamic range. Conclusion: The ability to permanently record (and interrogate at a later time) integrated 3D dose distributions will be valuable in assessing complex external beam treatment plans such as radiosurgical treatment plans as well as in commissioning and periodic checking of dynamic wedges, multileaf collimators, etc. used for conventionally fractionated conformal radiotherapy. The linearity of response and wide dynamic range are important in the evaluation of radiosurgical

  5. CudaPre3D: An Alternative Preprocessing Algorithm for Accelerating 3D Convex Hull Computation on the GPU

    MEI, G.

    2015-05-01

    Full Text Available In the calculating of convex hulls for point sets, a preprocessing procedure that is to filter the input points by discarding non-extreme points is commonly used to improve the computational efficiency. We previously proposed a quite straightforward preprocessing approach for accelerating 2D convex hull computation on the GPU. In this paper, we extend that algorithm to being used in 3D cases. The basic ideas behind these two preprocessing algorithms are similar: first, several groups of extreme points are found according to the original set of input points and several rotated versions of the input set; then, a convex polyhedron is created using the found extreme points; and finally those interior points locating inside the formed convex polyhedron are discarded. Experimental results show that: when employing the proposed preprocessing algorithm, it achieves the speedups of about 4x on average and 5x to 6x in the best cases over the cases where the proposed approach is not used. In addition, more than 95 percent of the input points can be discarded in most experimental tests.

  6. 3D Computational Simulation of Calcium Leaching in Cement Matrices

    Gaitero, J. J.

    2014-12-01

    Full Text Available Calcium leaching is a degradation process consisting in progressive dissolution of the cement paste by migration of calcium atoms to the aggressive solution. It is therefore, a complex phenomenon involving several phases and dissolution and diffusion processes simultaneously. Along this work, a new computational scheme for the simulation of the degradation process in three dimensions was developed and tested. The toolkit was used to simulate accelerated calcium leaching by a 6M ammonium nitrate solution in cement matrices. The obtained outputs were the three dimensional representation of the matrix and the physicochemical properties of individual phases as a consequence of the degradation process. This not only makes it possible to study the evolution of such properties as a function of time but also as a function of the position within the matrix. The obtained results are in good agreement with experimental values of the elastic modulus in degraded and undegraded samples.El lixiviado de calcio es un proceso de degradación consistente en la disolución progresiva de la pasta de cemento por la migración de los átomos de calcio a la disolución agresiva. Se trata por tanto de un fenómeno complejo que involucra simultáneamente diferentes fases y procesos de disolución y difusión. En este trabajo se desarrolló y probó una nueva herramienta computacional para la simulación del proceso de degradación en tres dimensiones. Para ello se simuló el lixiviado de calcio acelerado provocado por una disolución de nitrato amónico 6M en matrices de cemento. Como resultado se obtuvieron la representación tridimensional de la matriz y las propiedades físico-químicas sus fases a lo largo del tiempo. Esto permitió estudiar la evolución de dichas propiedades a lo largo del proceso de degradación así como en función de su posición dentro de la matriz. Los resultados obtenidos coinciden con los valores experimentales del módulo elástico tanto

  7. On the computation of long period seismograms in a 3-D earth using normal mode based approximations

    Romanowicz, Barbara A.; Panning, Mark P.; Gung, Yuancheng; Capdeville, Yann

    2008-11-01

    Tomographic inversions for large-scale structure of the earth's mantle involve a forward modelling step of wave propagation through 3-D heterogeneity. Until now, most investigators have worked in the framework of the simplest theoretical assumptions, namely the infinite frequency `ray theory' in the case of body wave traveltime inversions, or the `path-average' approximation (PAVA) to normal mode perturbation theory, in the case of surface waves and long-period waveforms. As interest is shifting to mapping shorter wavelength structures, the need for a more accurate theoretical account of the interaction of seismic waves with mantle heterogeneity, coupled with improvements in path coverage, has been realized. Here we discuss different levels of approximations used in the context of normal mode perturbation theory, when modelling time domain seismic waveforms. We compare the performance of asymptotic approximations, which collapse the effects of 3-D structure onto the great circle vertical plane: the 1-D PAVA and a 2-D approximation called non-linear asymptotic coupling theory (NACT), which both are zeroth order asymptotic approximations. We then discuss how off-vertical plane effects can be introduced using higher order asymptotics. These computationally efficient approximations are compared to the linear Born formalism (BORN), which computes scattering integrals over the entire surface of the sphere. We point out some limitations of this linear formalism in the case of spatially extended anomalies, and show how that can be remedied through the introduction of a non-linear term (NBORN). All these approximations are referenced to a precise 3-D numerical computation afforded by the spectral element method. We discuss simple geometries, and explore a range of sizes of anomalies compared to the wavelength of the seismic waves considered, thus illustrating the range of validity and limitations of the various approximations considered.

  8. Diagnostic accuracy of multi-slice computed tomographic angiography in the detection of cerebral aneurysms

    Multislice computed tomographic angiography is a rapid and minimally invasive method for the detection of intracranial aneurysms. The purpose of this study was to compare Multislice computed tomographic angiography with digital subtraction angiography In the diagnosis of cerebral aneurysms. Patients and Methods: In this cross sectional study we evaluated 111 consecutive patients [42(37.8%) male and 69(62.2%) female], who were admitted under clinical symptoms and signs. suggestive of harboring an intracranial aneurysm by using a four detector Multislice computed tomographic angiography. Then we compared results of Multislice computed tomographic angiography with digital subtraction angiography results as a gold standard method. Digital subtraction angiography was performed by bilateral selective common carotid artery injections and either unilateral or bilateral vertebral artery injections, as necessary. Multislice computed tomographic angiography images were interpreted by one radiologist and digital subtraction angiography was performed by another radiologist who was blinded to the interpretation of the Multislice computed tomographic angiograms. Results: The mean ±S D age of the patients was 49.1±13.6 years (range: 12-84 years). We performed Multislice computed tomographic in 111 and digital subtraction angiography in 85 patients. The sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratio of Multislice computed tomographic angiography, when compared with digital subtraction angiography as the gold standard, were 100%, 90%, 87.5%, 100%, 10 and 0, respectively. Conclusion: Multislice computed tomographic angiography seems to be an accurate and noninvasive imaging modality in the diagnosis of intracranial aneurysms

  9. Effect of coordinate rotation on 3D molecular descriptors computed by DragonX

    Hechinger, Manuel

    2012-01-01

    Quantitative structure-property relations (QSPR) employing descriptors derived from the 3D molecular structure are frequently applied for property prediction in various fields of research. In particular, DragonX is one of the most widely used software packages for descriptor calculation. The reliability of 3D molecular descriptors computed by DragonX has lately been investigated, thereby focusing on the effect of computational methods used for molecular structure optimization on the accuracy of the resulting molecular descriptors. The present contribution extends the analysis to a more intrinsic problem of DragonX descriptor evaluation resulting from the sensitivity of the computed 3D descriptors on the coordinate system used for molecule description. Evaluating several 3D descriptors for converged molecular structures rotated around all 3 spatial axes (affine coordinate transformations) yields systematically varying descriptor values. Since this unphysical behavior severely affects the descriptor reliability...

  10. The research of clinical application of computed tomographic virtual gastroscopy

    Objective: To investigate the values, methods and findings of computed tomographic virtual gastroscopy (CTVG). Methods: Sixty-nine patients underwent the examination of spiral CT after charged air into stomachs in different cubage. The CT scan conditions were collimating width 3 mm, pitch 1.2 - 2.5, scanning speed 0.8 s/360 degree, the raw data of CT volume scan was reconstructed in overlapping rate 33% - 67%. Then the images of CTVG were built using navigator software (GE AG, USA). Results: The accuracy, sensitivity, and specificity of CTVG were 92.8%, 96.4%, and 78.6%, respectively. CTVG corresponded well with fibrous gastroscopy and specimens in demonstrating the gastric lesions. CTVG was provided with the ability of revealing the tiny lesions of chronic atrophic gastritis, chronic erosive gastritis, chronic proliferative gastritis, and acute hemorrhagic gastritis in some degree. The high quality imaging of CTVG could be obtained in condition of collimating width 3 mm, pitch 1.2 - 1.5, overlapping 50% - 67%, well hold-breath, gastric cubage in full and feasible scan positions. Conclusion: CTVG is a rising means of gastric examination and has great value in clinic applications

  11. Colorectal Laterally Spreading Tumors by Computed Tomographic Colonography

    Yasuo Kakugawa

    2013-12-01

    Full Text Available To date, few reports focused primarily on detecting colorectal laterally spreading tumors (LSTs have been published. The aim of this study was to determine the visibility of LSTs on computed tomographic colonography (CTC compared with that on colonoscopy as a standard. We retrospectively reviewed and matched data on endoscopic and CTC reports in 157 patients (161 LSTs who received a multidetector CT scan using contrast media immediately after total colonoscopy at the National Cancer Center Hospital in Tokyo, Japan, between December 2005 and August 2010. The results of the total colonoscopy were known at the time of the CTC procedure and reading. Of the 161 LSTs detected on colonoscopy, 138 were observed and matched by CTC (86%. Of the 91 granular type LSTs (LST-Gs, 88 (97% were observed and matched, while of the 70 non-granular type LSTs (LST-NGs, 50 (71% were observed and matched by CTC (p < 0.0001. CTC enabled observation of 73% (22/30 of 20–29 mm, 83% (35/42 of 30–39 mm, 88% (49/56 of 40–59 mm, and 97% (32/33 of ≥60 mm tumors. The rate of observed LSTs by CTC was 86% (97% of LST-G, 71% of LST-NG of the LSTs found during total colonoscopy.

  12. Extracolonic findings of computed tomographic colonography in Koreans

    Sung Keun Park; Dong Il Park; Sun-Young Lee; Sang Kil Lee; Young-Ho Kim; Soon Jin Lee; Jeong-Sik Byeon; Kyu Chan Huh; Ki-Nam Shim

    2009-01-01

    AIM:To determine the frequency and characteristics of extracolonic lesions detected using computed tomographic (CT) colonography. METHODS:The significance of extracolonic lesions was classified as high, intermediate, or low. Medical records were reviewed to establish whether further investigations were carried out pertaining to the extracolonic lesions that were detected by CT colonography. RESULTS:A total of 920 cases from 7 university hospitals were included, and 692 extracolonic findings were found in 532 (57.8%) patients. Of 692 extracolonic findings, 60 lesions (8.7%) were highly significant, 250 (36.1%) were of intermediate significance, and 382 (55.2%) were of low significance. CT colonography revealed fewer extracolonic findings in subjects who were without symptoms ( P < 0.001), younger ( P < 0.001), or who underwent CT colonography with no contrast enhancement ( P = 0.005). CT colonography with contrast enhancement showed higher cost-effectiveness in detecting highly significant extracolonic lesions in older subjects and in subjects with symptoms. CONCLUSION:Most of the extracolonic findings d e t e c t e d u s i n g C T c o l o n o g ra p hy w e r e o f l e s s significant lesions. The role of CT colonography would be optimized if this procedure was performed with contrast enhancement in symptomatic older subjects.

  13. An Approach to Computer Modeling of Geological Faults in 3D and an Application

    ZHU Liang-feng; HE Zheng; PAN Xin; WU Xin-cai

    2006-01-01

    3D geological modeling, one of the most important applications in geosciences of 3D GIS, forms the basis and is a prerequisite for visualized representation and analysis of 3D geological data. Computer modeling of geological faults in 3D is currently a topical research area. Structural modeling techniques of complex geological entities containing reverse faults are discussed and a series of approaches are proposed. The geological concepts involved in computer modeling and visualization of geological fault in 3D are explained, the type of data of geological faults based on geological exploration is analyzed, and a normative database format for geological faults is designed. Two kinds of modeling approaches for faults are compared: a modeling technique of faults based on stratum recovery and a modeling technique of faults based on interpolation in subareas. A novel approach, called the Unified Modeling Technique for stratum and fault, is presented to solve the puzzling problems of reverse faults, syn-sedimentary faults and faults terminated within geological models. A case study of a fault model of bed rock in the Beijing Olympic Green District is presented in order to show the practical result of this method. The principle and the process of computer modeling of geological faults in 3D are discussed and a series of applied technical proposals established. It strengthens our profound comprehension of geological phenomena and the modeling approach, and establishes the basic techniques of 3D geological modeling for practical applications in the field of geosciences.

  14. Combined application of virtual imaging techniques and three-dimensional computed tomographic angiography in diagnosing intracranial aneurysms

    2008-01-01

    Background The diagnostic value of virtual imaging combined with three-dimensional computed tomographic angiography (3D-CTA) for intracranial aneurysms has not been fully elucidated yet. This study aimed to evaluate the value of combined application of virtual imaging techniques and 3D-CTA in diagnosing patients with aneurismal subarachnoid hemorrhage (SAH) at the acute stage. Methods Eighty patients with non-traumatic SAH received 3D-CTA examinations. The raw CT data of these patients were reconstructed and transferred into the 3D mode through the surgical plan system based on virtual reality (VR) image, and the 3D virtual images of skulls and brain blood vessels were acquired. The location, size and shape of aneurysms and their anatomic relationship with adjacent tissues were measured from many points of view. Results Seventy-three aneurysms were detected in 68 of the 80 patients, but 2 aneurysms were detected in 2 of the 5 patients who had been found free of aneurysms previously and had received 3D-CTA examinations for a second time one month later. The 3D virtual images produced by the virtual imaging system were clear and vivid, and they could reveal the location and size of the aneurysm and its relations to the parent artery and skull directly. Conclusions The imaging of 3D-CTA is convenient, reliable and fast in diagnosing intracranial aneurysms and can be regarded as the first choice for the diagnosis and treatment of ruptured intracranial aneurysms. Combined with the surgical plan system based on the VR image, 3D-CTA may obtain more imaging information about aneurysms.

  15. Clinical usefulness of multi-planar reconstruction images of three-dimensional computed tomographic angiography for internal carotid artery aneurysms

    The usefulness of multi-planar reconstruction (MPR) images of three-dimensional computed tomographic angiography (3D-CTA) for the diagnosis of internal carotid artery (ICA) aneurysms is described. Eleven unruptured ICA aneurysms including six cases of IC-cavernous aneurysm, two cases of IC-ophthalmic artery aneurysm, two cases of IC-posterior communicating artery aneurysm and one cases of IC-anterior choroidal artery aneurysm, were examined by magnetic resonance angiography (MRA), digital subtraction angiography (DSA), 3D-CTA and its MPR images. 3D-CTA and DSA were useful to identify the aneurysmal neck in small aneurysms, but it was difficult to identify the aneurysmal neck in small aneurysms by 3D-CTA-MPR images. DSA and MRA were not useful for identifying the aneurysmal neck in aneurysms more than 10 mm in diameter, as a precise viewing of the neck could not be found due to their large size. For large aneurysms, neither was 3D-CTA useful for identifying the aneurysmal neck when their large size and surrounding bony structures overlapped the aneurysmal neck. On the other hand, 3D-CTA-MPR was very useful for identifying the aneurysmal neck without overlapping by surrounding bony structures. 3D-CTA-MPR images clearly visualized the calcification of the wall. 3D-CTA-MPR images are obtained from 3D-CTA source images without any additional stress to the patients, and they are more useful for the diagnosis as well as demonstration of the aneurysmal neck particularly in more than large aneurysms. (author)

  16. Clinical usefulness of multi-planar reconstruction images of three-dimensional computed tomographic angiography for internal carotid artery aneurysms

    Nishio, Akimasa; Hara, Mitsuhiro; Nakamura, Kazuhito; Yamauchi, Shigeru; Tsuchida, Kazuyuki; Inoue, Yuichi; Daikokuya, Hideo [Osaka City Univ. (Japan). Medical School

    2002-03-01

    The usefulness of multi-planar reconstruction (MPR) images of three-dimensional computed tomographic angiography (3D-CTA) for the diagnosis of internal carotid artery (ICA) aneurysms is described. Eleven unruptured ICA aneurysms including six cases of IC-cavernous aneurysm, two cases of IC-ophthalmic artery aneurysm, two cases of IC-posterior communicating artery aneurysm and one cases of IC-anterior choroidal artery aneurysm, were examined by magnetic resonance angiography (MRA), digital subtraction angiography (DSA), 3D-CTA and its MPR images. 3D-CTA and DSA were useful to identify the aneurysmal neck in small aneurysms, but it was difficult to identify the aneurysmal neck in small aneurysms by 3D-CTA-MPR images. DSA and MRA were not useful for identifying the aneurysmal neck in aneurysms more than 10 mm in diameter, as a precise viewing of the neck could not be found due to their large size. For large aneurysms, neither was 3D-CTA useful for identifying the aneurysmal neck when their large size and surrounding bony structures overlapped the aneurysmal neck. On the other hand, 3D-CTA-MPR was very useful for identifying the aneurysmal neck without overlapping by surrounding bony structures. 3D-CTA-MPR images clearly visualized the calcification of the wall. 3D-CTA-MPR images are obtained from 3D-CTA source images without any additional stress to the patients, and they are more useful for the diagnosis as well as demonstration of the aneurysmal neck particularly in more than large aneurysms. (author)

  17. Computed tomographic high-attenuation mediastinal lymph nodes after aluminum exposition

    Vahlensieck, M.; Overlack, A. [Medical Faculty, Univ. of Bonn (Germany); Mueller, K.M. [Inst. fuer Pathologie, Kliniken Bergmannsheil, Bochum (Germany)

    2000-12-01

    A case with increased computed tomographic densities of mediastinal lymph nodes with histologically proven aluminum storage is presented. We suggest consideration of aluminosis as differential diagnosis in patients with increased native CT densities beyond 50 HU. (orig.)

  18. 3-D field computation: The near-triumph of commerical codes

    Turner, L.R.

    1995-07-01

    In recent years, more and more of those who design and analyze magnets and other devices are using commercial codes rather than developing their own. This paper considers the commercial codes and the features available with them. Other recent trends with 3-D field computation include parallel computation and visualization methods such as virtual reality systems.

  19. 3D SPIRAL COMPUTED TOMOGRAPHY FOR THE DIAGNOSIS OF AN ABDOMINAL TUMOUR

    R.C. Tiutiuca; Iuliana Eva

    2006-01-01

    Patients with digestive illnesses requires a full exploration, cases where imagistic assets support (echographic examination, radiological data, computed tomography, magnetic resonance) are very usefully. Computed tomography, in this process, has a special value. The results from axial images are sustained by the informations supplied from three-dimensional reconstruction processes (3D reconstruction) with relevant importance in establishment of diagnosis and therapeutic plan.

  20. 3D-SoftChip: A Novel Architecture for Next-Generation Adaptive Computing Systems

    Lee Mike Myung-Ok

    2006-01-01

    Full Text Available This paper introduces a novel architecture for next-generation adaptive computing systems, which we term 3D-SoftChip. The 3D-SoftChip is a 3-dimensional (3D vertically integrated adaptive computing system combining state-of-the-art processing and 3D interconnection technology. It comprises the vertical integration of two chips (a configurable array processor and an intelligent configurable switch through an indium bump interconnection array (IBIA. The configurable array processor (CAP is an array of heterogeneous processing elements (PEs, while the intelligent configurable switch (ICS comprises a switch block, 32-bit dedicated RISC processor for control, on-chip program/data memory, data frame buffer, along with a direct memory access (DMA controller. This paper introduces the novel 3D-SoftChip architecture for real-time communication and multimedia signal processing as a next-generation computing system. The paper further describes the advanced HW/SW codesign and verification methodology, including high-level system modeling of the 3D-SoftChip using SystemC, being used to determine the optimum hardware specification in the early design stage.

  1. 3D COMPUTER SIMULATION FOR LIGNIFICATION OF ANCIENT CHINESE TIMBER BUILDINGS

    2001-01-01

    A pioneer research work was carried out by investigators engaged in surveying and mapping for describing ancient Chinese timber buildings by 3D frame graphs w ith a computer.Users can know the structural layers and the assembly process of the se buildings if the frame graphs are processed further with a computer model.Th is can be implemented by computer simulation technique.This technique display t he raw data on the screen of a computer and interactively manage them by combini ng technologies from computer graphics and image processing,multi-media technol ogy,artificial intelligence,highly parallel real-time computation technique an d human behavior science.This paper presents the implementing procedure of ligni fi cation simulation for large-sized wooden buildings as well as 3D dynamic assembl y of these buildings under the 3DS MAX environment.The results from computer sim ulation are also shown in the paper.

  2. 3D Slicer as an image computing platform for the Quantitative Imaging Network.

    Fedorov, Andriy; Beichel, Reinhard; Kalpathy-Cramer, Jayashree; Finet, Julien; Fillion-Robin, Jean-Christophe; Pujol, Sonia; Bauer, Christian; Jennings, Dominique; Fennessy, Fiona; Sonka, Milan; Buatti, John; Aylward, Stephen; Miller, James V; Pieper, Steve; Kikinis, Ron

    2012-11-01

    Quantitative analysis has tremendous but mostly unrealized potential in healthcare to support objective and accurate interpretation of the clinical imaging. In 2008, the National Cancer Institute began building the Quantitative Imaging Network (QIN) initiative with the goal of advancing quantitative imaging in the context of personalized therapy and evaluation of treatment response. Computerized analysis is an important component contributing to reproducibility and efficiency of the quantitative imaging techniques. The success of quantitative imaging is contingent on robust analysis methods and software tools to bring these methods from bench to bedside. 3D Slicer is a free open-source software application for medical image computing. As a clinical research tool, 3D Slicer is similar to a radiology workstation that supports versatile visualizations but also provides advanced functionality such as automated segmentation and registration for a variety of application domains. Unlike a typical radiology workstation, 3D Slicer is free and is not tied to specific hardware. As a programming platform, 3D Slicer facilitates translation and evaluation of the new quantitative methods by allowing the biomedical researcher to focus on the implementation of the algorithm and providing abstractions for the common tasks of data communication, visualization and user interface development. Compared to other tools that provide aspects of this functionality, 3D Slicer is fully open source and can be readily extended and redistributed. In addition, 3D Slicer is designed to facilitate the development of new functionality in the form of 3D Slicer extensions. In this paper, we present an overview of 3D Slicer as a platform for prototyping, development and evaluation of image analysis tools for clinical research applications. To illustrate the utility of the platform in the scope of QIN, we discuss several use cases of 3D Slicer by the existing QIN teams, and we elaborate on the future

  3. Computed tomographic features of lymphangioleiomyomatosis: Evaluation in 138 patients

    Highlights: •In our series, the frequency of pulmonary nodules was higher than in the previous reports. •Our sporadic LAM patients had a lower frequency of renal AML than in that of previous reports. •LAM patients may have a high incidence of renal and hepatic cysts. •LAM cells may originate in the pelvis then spread via the axial lymphatic system. -- Abstract: Purpose: The aim was to characterize the computed tomographic (CT) findings from Japanese patients with lymphangioleiomyomatosis (LAM). Materials and methods: CT scans of the chest, abdomen, and pelvis from 124 patients with sporadic LAM (S-LAM, mean age, 37.4 years) and 14 patients with tuberous sclerosis complex (TSC)-LAM (mean age, 35.6 years) were analyzed. Results: Pulmonary nodules (18.8%) and hepatic angiomyolipoma (AML, 24.3%) were more common in our patients than those in previous reports. Compared with TSC-LAM, S-LAM group had a higher frequency of pulmonary nodules (28.6% vs 32.3%, P < 0.01) and lower frequencies of air-space consolidation (21.4% vs 2.4%, P < 0.01), pneumothorax (28.6% vs 8.1%, P = 0.02), pulmonary hilar lymphadenopathy (14.3% vs 0.8%, P < 0.01), renal AML (85.7% vs 17.4%, P < 0.01), hepatic AML (71.4% vs 17.4%, P < 0.01), and retrocrural lymphadenopathy (14.3% vs 1.4%, P = 0.04). Axial lymphatic abnormalities (i.e., thoracic duct dilatation, lymphadenopathy, and lymphangioleiomyoma) were most common in the pelvis and tended to decrease in incidence with increased distance from the pelvis. Conclusion: The incidence of some CT findings in Japanese patients differed from those in previous reports. Axial lymphatic abnormalities noted here suggest that the origin of LAM cells may be the pelvis

  4. Computed tomographic features of lymphangioleiomyomatosis: Evaluation in 138 patients

    Tobino, Kazunori, E-mail: tobino@juntendo.ac.jp [Department of Respiratory Medicine, Iizuka Hospital, 3-83 Yoshiomachi, Iizuka, Fukuoka 820-0018 (Japan); Division of Respiratory Medicine, Juntendo University Faculty of Medicine & Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421 (Japan); The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Johkoh, Takeshi [Department of Radiology, Kinki Central Hospital of Mutual Aid Association of Public School Teachers, Kurumazuka 3-1, Itami, Hyogo 664-0872 (Japan); Fujimoto, Kiminori [Department of Radiology, Kurume University School of Medicine and Center for Diagnostic Imaging, Kurume University Hospital, 67 Asahi-machi, Kurume, Fukuoka 830-0011 (Japan); Sakai, Fumikazu [Department of Diagnostic Radiology, Saitama International Medical Center, Saitama Medical University, 1397-1 Yamane, Hidaka, Saitama 350-1298 (Japan); Arakawa, Hiroaki [Department of Radiology, Dokkyo Medical University, 880 Kita-Kobayashi, Mibu, Tochigi 321-0293 (Japan); Kurihara, Masatoshi [The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Pneumothorax Center, Nissan Tamagawa Hospital, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Kumasaka, Toshio [The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan); Department of Pathology, Japanese Red Cross Medical Center, 4-1-22 Hiroo, Shibuya-Ku, Tokyo 150-0012 (Japan); Koike, Kengo; Takahashi, Kazuhisa [Division of Respiratory Medicine, Juntendo University Faculty of Medicine & Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421 (Japan); Seyama, Kuniaki [Division of Respiratory Medicine, Juntendo University Faculty of Medicine & Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo 113-8421 (Japan); The Study Group of Pneumothorax and Cystic Lung Diseases, 4-8-1 Seta, Setagaya-Ku, Tokyo 158-0095 (Japan)

    2015-03-15

    Highlights: •In our series, the frequency of pulmonary nodules was higher than in the previous reports. •Our sporadic LAM patients had a lower frequency of renal AML than in that of previous reports. •LAM patients may have a high incidence of renal and hepatic cysts. •LAM cells may originate in the pelvis then spread via the axial lymphatic system. -- Abstract: Purpose: The aim was to characterize the computed tomographic (CT) findings from Japanese patients with lymphangioleiomyomatosis (LAM). Materials and methods: CT scans of the chest, abdomen, and pelvis from 124 patients with sporadic LAM (S-LAM, mean age, 37.4 years) and 14 patients with tuberous sclerosis complex (TSC)-LAM (mean age, 35.6 years) were analyzed. Results: Pulmonary nodules (18.8%) and hepatic angiomyolipoma (AML, 24.3%) were more common in our patients than those in previous reports. Compared with TSC-LAM, S-LAM group had a higher frequency of pulmonary nodules (28.6% vs 32.3%, P < 0.01) and lower frequencies of air-space consolidation (21.4% vs 2.4%, P < 0.01), pneumothorax (28.6% vs 8.1%, P = 0.02), pulmonary hilar lymphadenopathy (14.3% vs 0.8%, P < 0.01), renal AML (85.7% vs 17.4%, P < 0.01), hepatic AML (71.4% vs 17.4%, P < 0.01), and retrocrural lymphadenopathy (14.3% vs 1.4%, P = 0.04). Axial lymphatic abnormalities (i.e., thoracic duct dilatation, lymphadenopathy, and lymphangioleiomyoma) were most common in the pelvis and tended to decrease in incidence with increased distance from the pelvis. Conclusion: The incidence of some CT findings in Japanese patients differed from those in previous reports. Axial lymphatic abnormalities noted here suggest that the origin of LAM cells may be the pelvis.

  5. 3D computed tomographic evaluation of secondary alveolar bone grafts in cleft lip and palate patients

    Alveolar bone grafting in patients with cleft lip and palate has becomes a routine part of most treatment regimes. This study was undertaken to estimate how much bone needs to be grafted into the cleft cavity and to evaluate the grafted bone using 3-DCT over a period from the early postoperative stage to after one year. Seventy-five patients divided into four groups according to the type of cleft were studied. All patients underwent secondary alveolar bone grafting using particulate cancellous bone from the anterior iliac crest. The bone graft areas were divided into two regions: the extra-cleft region and the intra-cleft region. The weight and the volume of the grafted bone were correlated and the average density was 1.5 g/ml regardless of the cleft type. The bone in the extra-cleft region could be seen in almost all slices of the CT scans, from the lower alveolar process to the piriform aperture. The extra-cleft graft ratio of unilateral and bilateral cleft lip and palate is higher than that of cleft lip and alveolus. The extra-cleft grafting is necessary to restore facial symmetry. The grafted bone was decreased in both height and volume following three months and adequate bone bridging was maintained for one year. We concluded that 3-DCT findings are one of the most valuable methods to evaluate postoperative conditions after alveolar bone grafting. (author)

  6. 3D computed tomographic evaluation of secondary alveolar bone grafts in cleft lip and palate patients

    Ohkubo, Fumio; Akai, Hidemi; Hosaka, Yoshiaki [Showa Univ., Tokyo (Japan). School of Medicine

    2001-04-01

    Alveolar bone grafting in patients with cleft lip and palate has becomes a routine part of most treatment regimes. This study was undertaken to estimate how much bone needs to be grafted into the cleft cavity and to evaluate the grafted bone using 3-DCT over a period from the early postoperative stage to after one year. Seventy-five patients divided into four groups according to the type of cleft were studied. All patients underwent secondary alveolar bone grafting using particulate cancellous bone from the anterior iliac crest. The bone graft areas were divided into two regions: the extra-cleft region and the intra-cleft region. The weight and the volume of the grafted bone were correlated and the average density was 1.5 g/ml regardless of the cleft type. The bone in the extra-cleft region could be seen in almost all slices of the CT scans, from the lower alveolar process to the piriform aperture. The extra-cleft graft ratio of unilateral and bilateral cleft lip and palate is higher than that of cleft lip and alveolus. The extra-cleft grafting is necessary to restore facial symmetry. The grafted bone was decreased in both height and volume following three months and adequate bone bridging was maintained for one year. We concluded that 3-DCT findings are one of the most valuable methods to evaluate postoperative conditions after alveolar bone grafting. (author)

  7. 3D Printing of Preclinical X-ray Computed Tomographic Data Sets

    Doney, Evan; Krumdick, Lauren A.; Diener, Justin M.; Wathen, Connor A.; Chapman, Sarah E.; Stamile, Brian; Scott, Jeremiah E.; Ravosa, Matthew J.; van Avermaete, Tony; Leevy, W. Matthew

    2013-01-01

    Three-dimensional printing allows for the production of highly detailed objects through a process known as additive manufacturing. Traditional, mold-injection methods to create models or parts have several limitations, the most important of which is a difficulty in making highly complex products in a timely, cost-effective manner.1 However, gradual improvements in three-dimensional printing technology have resulted in both high-end and economy instruments that are now available for the facile...

  8. Efficient computation of steady, 3D water-wave patterns, application to hovercraft-type flows

    Lewis, M. R.; Koren, Barry

    2002-01-01

    Numerical methods for the computation of stationary free surfaces is the subject of much current research in computational engineering. The present report is directed towards free surfaces in maritime engineering. Of interest here are the long steady waves generated by hovercraft and ships, the gravity waves. In the present report an existing 2D iterative method for the computation of stationary gravity-wave solutions is extended to 3D, numerically investigated, and improved. The method emplo...

  9. Creation of 3D digital computer model of radiation conditions about ChNPP

    Information technology for creation of 3D digital computer model of radiation conditions (RC) around the ChNPP was developed on the basis of geo information technologies. 3D digital computer model of the RC was created, which is aimed at taking of decisions and situational modeling. Data analysis on the RC within the 30 km exclusion zone was carried out and the RC data base was created. Surface distribution and volumetric digital model of 137Cs on the area adjoining to the ChNPP industrial site were made

  10. Development of 3-D Radiosurgery Planning System Using IBM Personal Computer

    Recently, stereotactic radiosurgery plan is required with the information of 3-D image and dose distribution. A project has been doing if developing LINAC based stereotactic radiosurgery since April 1991. The purpose of this research is to develop 3-D radiosurgery planning system using personal computer. The procedure of this research is based on two steps. The first step is to develop 3-D localization system, which input the image information of the patient, coordinate transformation, the position and shape of target, and patient contour into computer system using CT image and stereotactic frame. The second step is to develop 3-D dose planning system, which compute dose distribution on image plane, display on high resolution monitor both isodose distribution and patient image simultaneously and develop menu-driven planning system. This prototype of radiosurgery planning system was applied recently for several clinical cases. It was shown that our planning system is fast, accurate and efficient while making it possible to handle various kinds of image modalities such as angiography, CT and MRI. It makes it possible to develop general 3-D planning system using beam eye view or CT simulation in radiation therapy in future

  11. 3-D Multiphase Segmentation of X-Ray Micro Computed Tomography Data of Geologic Materials

    Tuller, M.; Kulkarni, R.; Fink, W.

    2011-12-01

    Advancements of noninvasive imaging methods such as X-Ray Computed Tomography (CT) led to a recent surge of applications in Geoscience. While substantial efforts and resources have been devoted to advance CT technology and micro-scale analysis, the development of a stable 3-D multiphase image segmentation method applicable to large datasets is lacking. To eliminate the need for wet/dry or dual energy scans, image alignment, and subtraction analysis, commonly applied in synchrotron X-Ray micro CT, a segmentation method based on a Bayesian Markov Random Field (MRF) framework amenable to true 3-D multiphase processing was developed and evaluated. Furthermore, several heuristic and deterministic combinatorial optimization schemes required to solve the labeling problem of the MRF image model were implemented and tested for computational efficiency and their impact on segmentation results. Test results for natural and artificial porous media datasets demonstrate great potential of the MRF image model for 3-D multiphase segmentation.

  12. Computer-Assisted Hepatocellular Carcinoma Ablation Planning Based on 3-D Ultrasound Imaging.

    Li, Kai; Su, Zhongzhen; Xu, Erjiao; Guan, Peishan; Li, Liu-Jun; Zheng, Rongqin

    2016-08-01

    To evaluate computer-assisted hepatocellular carcinoma (HCC) ablation planning based on 3-D ultrasound, 3-D ultrasound images of 60 HCC lesions from 58 patients were obtained and transferred to a research toolkit. Compared with virtual manual ablation planning (MAP), virtual computer-assisted ablation planning (CAP) consumed less time and needle insertion numbers and exhibited a higher rate of complete tumor coverage and lower rate of critical structure injury. In MAP, junior operators used less time, but had more critical structure injury than senior operators. For large lesions, CAP performed better than MAP. For lesions near critical structures, CAP resulted in better outcomes than MAP. Compared with MAP, CAP based on 3-D ultrasound imaging was more effective and achieved a higher rate of complete tumor coverage and a lower rate of critical structure injury; it is especially useful for junior operators and with large lesions, and lesions near critical structures. PMID:27126243

  13. Analyzing 3D xylem networks in Vitis vinifera using High Resolution Computed Tomography (HRCT)

    Recent developments in High Resolution Computed Tomography (HRCT) have made it possible to visualize three dimensional (3D) xylem networks without time consuming, labor intensive physical sectioning. Here we describe a new method to visualize complex vessel networks in plants and produce a quantitat...

  14. Detection of screw threads in computed tomography 3D density fields

    Kosarevsky, Sergey

    2013-01-01

    In this paper, a new method is proposed to automatically detect screw threads in 3D density fields obtained from computed tomography measurement devices. The described method can be used to automate many operations during screw thread inspection process and drastically reduce operator's influence on the measurement process resulting in lower measurement times and increased repeatability.

  15. Simplified 3D model of a PWR reactor vessel using fluid dynamics code ANSYS CFX computational

    This paper presents the results from the calculation of the steady state simulation with model of CFD (computational fluid dynamic) operating under conditions of operation at full power (Hot Full Power). Development and the CFD model results show the usefulness of these codes for calculating 3D of the variable thermohydraulics of these reactors.

  16. The Effects of 3D Computer Simulation on Biology Students' Achievement and Memory Retention

    Elangovan, Tavasuria; Ismail, Zurida

    2014-01-01

    A quasi experimental study was conducted for six weeks to determine the effectiveness of two different 3D computer simulation based teaching methods, that is, realistic simulation and non-realistic simulation on Form Four Biology students' achievement and memory retention in Perak, Malaysia. A sample of 136 Form Four Biology students in Perak,…

  17. 3D image fusion and guidance for computer-assisted bronchoscopy

    Higgins, W. E.; Rai, L.; Merritt, S. A.; Lu, K.; Linger, N. T.; Yu, K. C.

    2005-11-01

    The standard procedure for diagnosing lung cancer involves two stages. First, the physician evaluates a high-resolution three-dimensional (3D) computed-tomography (CT) chest image to produce a procedure plan. Next, the physician performs bronchoscopy on the patient, which involves navigating the the bronchoscope through the airways to planned biopsy sites. Unfortunately, the physician has no link between the 3D CT image data and the live video stream provided during bronchoscopy. In addition, these data sources differ greatly in what they physically give, and no true 3D planning tools exist for planning and guiding procedures. This makes it difficult for the physician to translate a CT-based procedure plan to the video domain of the bronchoscope. Thus, the physician must essentially perform biopsy blindly, and the skill levels between different physicians differ greatly. We describe a system that enables direct 3D CT-based procedure planning and provides direct 3D guidance during bronchoscopy. 3D CT-based information on biopsy sites is provided interactively as the physician moves the bronchoscope. Moreover, graphical information through a live fusion of the 3D CT data and bronchoscopic video is provided during the procedure. This information is coupled with a series of computer-graphics tools to give the physician a greatly augmented reality of the patient's interior anatomy during a procedure. Through a series of controlled tests and studies with human lung-cancer patients, we have found that the system not only reduces the variation in skill level between different physicians, but also increases biopsy success rate.

  18. Quantitative analysis of periapical lesions on cone beam computed tomograph and periapical radiograph

    To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

  19. Quantitative analysis of periapical lesions on cone beam computed tomograph and periapical radiograph

    Kim, Jin Hoa; Lee, Wan; Kim, Kyung Soo; Roh, Young Chea; Lee, Byung Do [Department of Oral and Maxillofacial Radiology, School of Dentistry, Wonkwang University, Iksan (Korea, Republic of); Kim, De Sok [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology, Deajeon (Korea, Republic of)

    2009-03-15

    To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

  20. Computer assisted determination of acetabular cup orientation using 2D-3D image registration

    2D-3D image-based registration methods have been developed to measure acetabular cup orientation after total hip arthroplasty (THA). These methods require registration of both the prosthesis and the CT images to 2D radiographs and compute implant position with respect to a reference. The application of these methods is limited in clinical practice due to two limitations: (1) the requirement of a computer-aided design (CAD) model of the prosthesis, which may be unavailable due to the proprietary concerns of the manufacturer, and (2) the requirement of either multiple radiographs or radiograph-specific calibration, usually unavailable for retrospective studies. In this paper, we propose a new method to address these limitations. A new formulation for determination of post-operative cup orientation, which couples a radiographic measurement with 2D-3D image matching, was developed. In our formulation, the radiographic measurement can be obtained with known methods so that the challenge lies in the 2D-3D image matching. To solve this problem, a hybrid 2D-3D registration scheme combining a landmark-to-ray 2D-3D alignment with a robust intensity-based 2D-3D registration was used. The hybrid 2D-3D registration scheme allows computing both the post-operative cup orientation with respect to an anatomical reference and the pelvic tilt and rotation with respect to the X-ray imaging table/plate. The method was validated using 2D adult cadaver hips. Using the hybrid 2D-3D registration scheme, our method showed a mean accuracy of 1.0 ± 0.7 (range from 0.1 to 2.0 ) for inclination and 1.7 ± 1.2 (range from 0.0 to 3.9 ) for anteversion, taking the measurements from post-operative CT images as ground truths. Our new solution formulation and the hybrid 2D-3D registration scheme facilitate estimation of post-operative cup orientation and measurement of pelvic tilt and rotation. (orig.)

  1. Computer assisted determination of acetabular cup orientation using 2D-3D image registration

    Zheng, Guoyan; Zhang, Xuan [University of Bern, Institute for Surgical Technology and Biomechanics, Bern (Switzerland)

    2010-09-15

    2D-3D image-based registration methods have been developed to measure acetabular cup orientation after total hip arthroplasty (THA). These methods require registration of both the prosthesis and the CT images to 2D radiographs and compute implant position with respect to a reference. The application of these methods is limited in clinical practice due to two limitations: (1) the requirement of a computer-aided design (CAD) model of the prosthesis, which may be unavailable due to the proprietary concerns of the manufacturer, and (2) the requirement of either multiple radiographs or radiograph-specific calibration, usually unavailable for retrospective studies. In this paper, we propose a new method to address these limitations. A new formulation for determination of post-operative cup orientation, which couples a radiographic measurement with 2D-3D image matching, was developed. In our formulation, the radiographic measurement can be obtained with known methods so that the challenge lies in the 2D-3D image matching. To solve this problem, a hybrid 2D-3D registration scheme combining a landmark-to-ray 2D-3D alignment with a robust intensity-based 2D-3D registration was used. The hybrid 2D-3D registration scheme allows computing both the post-operative cup orientation with respect to an anatomical reference and the pelvic tilt and rotation with respect to the X-ray imaging table/plate. The method was validated using 2D adult cadaver hips. Using the hybrid 2D-3D registration scheme, our method showed a mean accuracy of 1.0 {+-} 0.7 (range from 0.1 to 2.0 ) for inclination and 1.7 {+-} 1.2 (range from 0.0 to 3.9 ) for anteversion, taking the measurements from post-operative CT images as ground truths. Our new solution formulation and the hybrid 2D-3D registration scheme facilitate estimation of post-operative cup orientation and measurement of pelvic tilt and rotation. (orig.)

  2. Estimation of stochastic risk from computed tomographic examinations in Japan, 1979, 3

    The population doses and stochastic risks of hereditary, leukemia and malignant diseses from computed tomographic examinations were estimated on the basis of a 1979 nationwide survey of randomly sampled hospitals and clinics throughout Japan. The organ or tissue doses related to genetic effects and somatic effects were determined with a phantom measurement, using thermoluminescent dosimeters and seven types of computed tomographic scanners. The resultant annual population doses per person were 0.11 mrad (1.1 μGy) for genetically significant dose, 2.8 mrad (28 μGy) for per caput mean bone marrow dose, 2.2 mrad (22 μGy) for leukemia significant dose and 0.72 mrad (7.2 μGy) for malignancy significant dose, respectively. Assuming that computed tomographic examinations in 1979 will be performed continuously in the future, the population risks for the whole population in Japan were estimated to be 20 persons per year for total risks. As an example of results, the individual risks was 7.36 x 10-6 for 32 year old male and 8.23 x 10-6 for 32 year old female from clanial computed tomographic examinations and 101.0 x 10-6 for 12 year old male and 257 x 10-6 for 12 year old female from lower abdominal computed tomographic examinations. (author)

  3. The computation of steady 3-D separated flows over aerodynamic bodies at incidence and yaw

    Pulliam, T. H.; Pan, D.

    1986-01-01

    This paper describes the implementation of a general purpose 3-D NS code and its application to simulated 3-D separated vortical flows over aerodynamic bodies. The thin-layer Reynolds-averaged NS equations are solved by an implicit approximate factorization scheme. The pencil data structure enables the code to run on very fine grids using only limited incore memories. Solutions of a low subsonic flow over an inclined ellipsoid are compared with experimental data to validate the code. Transonic flows over a yawed elliptical wing at incidence are computed and separations occurred at different yaw angles are discussed.

  4. Histomorphometric quantification of human pathological bones from synchrotron radiation 3D computed microtomography

    Conventional bone histomorphometry is an important method for quantitative evaluation of bone microstructure. X-ray computed microtomography is a noninvasive technique, which can be used to evaluate histomorphometric indices in trabecular bones (BV/TV, BS/BV, Tb.N, Tb.Th, Tb.Sp). In this technique, the output 3D images are used to quantify the whole sample, differently from the conventional one, in which the quantification is performed in 2D slices and extrapolated for 3D case. In this work, histomorphometric quantification using synchrotron 3D X-ray computed microtomography was performed to quantify pathological samples of human bone. Samples of human bones were cut into small blocks (8 mm x 8 mm x 10 mm) with a precision saw and then imaged. The computed microtomographies were obtained at SYRMEP (Synchrotron Radiation for MEdical Physics) beamline, at ELETTRA synchrotron radiation facility (Italy). The obtained 3D images yielded excellent resolution and details of intra-trabecular bone structures, including marrow present inside trabeculae. Histomorphometric quantification was compared to literature as well. (author)

  5. A burnup corrected 3-D nodal depletion method for vector and parallel computer architectures

    The 2- and 3-D nodal depletion code NOMAD-BC was parallelized and vectorized (3-D only). A 3-D, 2-cycle depletion problem was devised and successfully solved with the NOMAD-BC code in less than 35 seconds on two CPUs of a Cray X-MP/48. This shows a combined vectorization and parallelization speedup of 8.6. The same problem was solved on a 2-CPU 16 MHz SGI workstation in less than one hour, exhibiting a 1.78 speedup over the single processor solution on the same machine. It is shown in this work that complex and detailed burnup computations can be successfully optimized. In addition, the performance achieved demonstrates the possibility of obtaining results within very reasonable times, even on inexpensive workstations. Finally, the small CPU time requirements should make possible the routine evaluation of fuel cycles at great savings of the engineer's time. (author)

  6. Using the CAVE virtual-reality environment as an aid to 3-D electromagnetic field computation

    One of the major problems in three-dimensional (3-D) field computation is visualizing the resulting 3-D field distributions. A virtual-reality environment, such as the CAVE, (CAVE Automatic Virtual Environment) is helping to overcome this problem, thus making the results of computation more usable for designers and users of magnets and other electromagnetic devices. As a demonstration of the capabilities of the CAVE, the elliptical multipole wiggler (EMW), an insertion device being designed for the Advanced Photon Source (APS) now being commissioned at Argonne National Laboratory (ANL), wa made visible, along with its fields and beam orbits. Other uses of the CAVE in preprocessing and postprocessing computation for electromagnetic applications are also discussed

  7. Performance assessment of KORAT-3D on the ANL IBM-SP computer

    The TENAR code is currently being developed at the Russian Federal Nuclear Center (VNIIEF) as a coupled dynamics code for the simulation of transients in VVER and RBMK systems and other nuclear systems. The neutronic module in this code system is KORAT-3D. This module is also one of the most computationally intensive components of the code system. A parallel version of KORAT-3D has been implemented to achieve the goal of obtaining transient solutions in reasonable computational time, particularly for RBMK calculations that involve the application of >100,000 nodes. An evaluation of the KORAT-3D code performance was recently undertaken on the Argonne National Laboratory (ANL) IBM ScalablePower (SP) parallel computer located in the Mathematics and Computer Science Division of ANL. At the time of the study, the ANL IBM-SP computer had 80 processors. This study was conducted under the auspices of a technical staff exchange program sponsored by the International Nuclear Safety Center (INSC)

  8. Evaluation of contrast-enhanced computed tomographic colonography in detection of local recurrent colorectal cancer

    Yau-Tong You; Chung-Rong Chang Chien; Jeng-Yi Wang; Koon-Kwan Ng; Jinn-Shiun Chen; Reiping Tang; Jy-Ming Chiang; Chien-Yuh Yeh; Pao-Shiu Hsieh

    2006-01-01

    AIM: To evaluate the diagnostic accuracy, sensitivity,specificity of contrast-enhanced computed tomographic colonography in detecting local recurrence of colorectal cancer.METHODS: From January 2000 to December 2004,434 patients after potentially curative resection for invasive colorectal cancer were followed up for a period ranging from 20 to 55 mo. Eighty of the four hundred and thirty-four patients showing strong clinical evidence for recurring colorectal cancer during the last followup were enrolled in this study. Each patient underwent contrast-enhanced computed tomographic colonography and colonoscopy on the same day. Any lesions, biopsies,identified during the colonoscopic examination, immediate complications and the duration of the procedure were recorded. The results of contrast-enhanced computed tomographic colonography were evaluated by comparing to those of colonoscopy, surgical finding, and clinical follow-up.RESULTS: Contrast-enhanced computed tomographic colonography had a sensitivity of 100%, a specificity of 83% and an overall accuracy of 94% in detecting local recurrent colorectal cancer.CONCLUSION: Conventional colonoscopy and contrastenhanced tomographic colonography can complement each other in detecting local recurrence of colorectal cancer.

  9. A Computer Vision Method for 3D Reconstruction of Curves-Marked Free-Form Surfaces

    Xiong Hanwei; Zhang Xiangwei

    2001-01-01

    Visual method is now broadly used in reverse engineering for 3D reconstruction. Thetraditional computer vision methods are feature-based, i.e., they require that the objects must revealfeatures owing to geometry or textures. For textureless free-form surfaces, dense feature points areadded artificially. In this paper, a new method is put forward combining computer vision with CAGD.The surface is subdivided into N-side Gregory patches using marked curves, and a stereo algorithm isused to reconstruct the curves. Then, the cross boundary tangent vector is computed throughreflectance analysis. At last, the whole surface can be reconstructed by jointing these patches withG1 continuity.

  10. 3D-MAPTOR Code for Computation of Magnetic Fields in Tokamaks

    Full text: A 3D code has been developed in order to simulate the magnetic field lines in tokamaks, in two versions. In the first one, the toroidal magnetic field can be obtained from the individual fields of circular coils arranged around the torus, or alternatively, as a ripple-less field. The poloidal field is provided by a given toroidal current density profile. In an upgraded version, rectangular toroidal field coils and D-shaped plasma cross sections have been included, in order to aid in the design of spherical tokamaks. Proposing initial conditions for magnetic filed lines, they are integrated along the toroidal angle coordinate, and Poincare maps can be obtained at any desired cross section plane along the toroidal coordinate. The evolution of the field lines is also monitored from above, so the ripple due to the toroidal field coils can be appreciated. The effects of loss of axisymmetry, either originated by ripples, or by additional external coils, such as an inner coil with tilted circular loops, can therefore be studied. This is useful for the study of breaking-up of external surfaces, as in the case of ergodic divertors. The code can also be used in order to reconstruct the evolution of the plasma column, using the experimental signals of tokamak discharges. In the latter case, the results have been compared with tomographic results of the ISTTOK tokamak. (author)

  11. Three-dimensional imaging using computer-generated holograms synthesized from 3-D Fourier spectra

    Yatagai, Toyohiko; Miura, Ken-ichi; Sando, Yusuke; Itoh, Masahide [University of Tsukba, Institute of Applied Physics, Tennoudai 1-1-1, Tsukuba, Ibaraki 305-8571 (Japan)], E-mail: yatagai@cc.utsunomiya-u.ac.jp

    2008-11-01

    Computer-generated holograms(CGHs) synthesized from projection images of real existing objects are considered. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD. According to the principles of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel CGH is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary. Moreover, when a color CCD is used in recording, it is easily possible to record and reconstruct colorful objects. Finally, we demonstrate reconstruction of biological objects.

  12. Three-dimensional imaging using computer-generated holograms synthesized from 3-D Fourier spectra

    Computer-generated holograms(CGHs) synthesized from projection images of real existing objects are considered. A series of projection images are recorded both vertically and horizontally with an incoherent light source and a color CCD. According to the principles of computer tomography(CT), the 3-D Fourier spectrum is calculated from several projection images of objects and the Fresnel CGH is synthesized using a part of the 3-D Fourier spectrum. This method has following advantages. At first, no-blur reconstructed images in any direction are obtained owing to two-dimensionally scanning in recording. Secondarily, since not interference fringes but simple projection images of objects are recorded, a coherent light source is not necessary. Moreover, when a color CCD is used in recording, it is easily possible to record and reconstruct colorful objects. Finally, we demonstrate reconstruction of biological objects.

  13. Gust Acoustics Computation with a Space-Time CE/SE Parallel 3D Solver

    Wang, X. Y.; Himansu, A.; Chang, S. C.; Jorgenson, P. C. E.; Reddy, D. R. (Technical Monitor)

    2002-01-01

    The benchmark Problem 2 in Category 3 of the Third Computational Aero-Acoustics (CAA) Workshop is solved using the space-time conservation element and solution element (CE/SE) method. This problem concerns the unsteady response of an isolated finite-span swept flat-plate airfoil bounded by two parallel walls to an incident gust. The acoustic field generated by the interaction of the gust with the flat-plate airfoil is computed by solving the 3D (three-dimensional) Euler equations in the time domain using a parallel version of a 3D CE/SE solver. The effect of the gust orientation on the far-field directivity is studied. Numerical solutions are presented and compared with analytical solutions, showing a reasonable agreement.

  14. Sand transverse dune aerodynamics: 3D Coherent Flow Structures from a computational study

    Bruno, Luca

    2015-01-01

    The engineering interest about dune fields is dictated by the their interaction with a number of human infrastructures in arid environments. The aerodynamic behaviour of sand dunes in atmospheric boundary layer belongs to the class of bluff bodies. Because of their simple geometry and their frequent occurrence in desert area, transverse sand dunes are usually adopted in literature as a benchmark to investigate dune aerodynamics by means of both computational or experimental approach, usually in nominally 2D setups. The writers suspect the flow in the wake is characterised by 3D features and affected by wind tunnel setup - e.g. blockage effect, duct side wall boundary layer, incoming velocity profile - when experimental studies are carried out. The present study aims at evaluating the 3D flow features of an idealised transverse dune under different setup conditions by means of computational simulations and to compare the obtained results with experimental measurements.

  15. Integration of 3D anatomical data obtained by CT imaging and 3D optical scanning for computer aided implant surgery

    Paoli Alessandro

    2011-02-01

    Full Text Available Abstract Background A precise placement of dental implants is a crucial step to optimize both prosthetic aspects and functional constraints. In this context, the use of virtual guiding systems has been recognized as a fundamental tool to control the ideal implant position. In particular, complex periodontal surgeries can be performed using preoperative planning based on CT data. The critical point of the procedure relies on the lack of accuracy in transferring CT planning information to surgical field through custom-made stereo-lithographic surgical guides. Methods In this work, a novel methodology is proposed for monitoring loss of accuracy in transferring CT dental information into periodontal surgical field. The methodology is based on integrating 3D data of anatomical (impression and cast and preoperative (radiographic template models, obtained by both CT and optical scanning processes. Results A clinical case, relative to a fully edentulous jaw patient, has been used as test case to assess the accuracy of the various steps concurring in manufacturing surgical guides. In particular, a surgical guide has been designed to place implants in the bone structure of the patient. The analysis of the results has allowed the clinician to monitor all the errors, which have been occurring step by step manufacturing the physical templates. Conclusions The use of an optical scanner, which has a higher resolution and accuracy than CT scanning, has demonstrated to be a valid support to control the precision of the various physical models adopted and to point out possible error sources. A case study regarding a fully edentulous patient has confirmed the feasibility of the proposed methodology.

  16. Computed Tomography and its Application for the 3D Characterization of Coarse Grained Meteorites

    Gillies, Donald C.; Engel, H. P.; Carpenter, P. K.

    2004-01-01

    With judicious selection of parameters, computed tomography can provide high precision density data. Such data can lead to a non-destructive determination of the phases and phase distribution within large solid objects. Of particular interest is the structure of the Mundrabilla meteorite, which has 25 volumes, percent of a sulfide within a metallic meteorite. 3D digital imaging has enabled a quantitative evaluation of the distribution and contiguity of the phases to be determined.

  17. Three dimensional field computation software package DE3D and its applications

    A software package DE3D, which can be run on PC, for three dimensional electrostatic and magnetostatic field computations is developed in China Institute of Atomic Energy. The features of the code and its applications are introduced. Typical examples are given on the design of a cyclotron magnet and magnetic elements on its beam transport line, which show how the program help the designer to improve his design of products

  18. 3D-Workbench : Design and Development of a 3-Dimension Computer Numerical Controlled Machine

    Sandru, Andrei

    2015-01-01

    The purpose of this thesis was to examine and develop a multipurpose Computer Numerical Controlled (CNC) device which would satisfy industrial requirements, but could also be implemented at universities for students to improve and apply their knowledge in different scopes. The topic was specifically chosen because of its close relation to a summer job at a metal factory the author completed and his personal fascination with 3D printers. The project presented in this thesis was commissioned...

  19. 3D Vertical Dual-Layer Oxide Memristive Devices for Neuromorphic Computing

    Gaba, Siddharth; Sheridan, Patrick; Du, Chao; Wei LU

    2014-01-01

    Dual-layer resistive switching devices with horizontal W electrodes, vertical Pd electrodes and WOx switching layer formed at the sidewall of the horizontal electrodes have been fabricated and characterized. The devices exhibit well-characterized analog switching characteristics and small mismatch in electrical characteristics for devices formed at the two layers. The three-dimensional (3D) vertical device structure allows higher storage density and larger connectivity for neuromorphic comput...

  20. Preoperative evaluation of the saphenous vein by 3-D contrastless computed tomography

    Maruyama, Yuji; Imura, Hajime; Shirakawa, Makoto; Ochi, Masami

    2013-01-01

    Volume-rendering computed tomography (CT) without contrast medium has clearly demonstrated the 3-D mapping of the saphenous vein (SV). Contrastless volume-rendering CT was used to preoperatively evaluate the SV anatomy before coronary artery bypass grafting (CABG). This technique was useful for atypical anatomical variations, such as partial duplication of SV (Case 1) or varicose veins (Case 2). Volume-rendering CT may also help with redo CABG (to determine remaining SV) or during endoscopic ...

  1. Computed tomographic study of 50 patients with hypodense hepatic injuries in childhood

    Objective: To describe the different tomographic findings in hypodense hepatic lesions in children and its differential diagnosis. Materials and methods: computed tomographic studies were obtained from 50 patients (age range: 0-16 years) with low-density liver lesions previously diagnosed by ultrasound. Images were made before and after administration of intravenous contrast medium. Image findings were analyzed and afterwards correlated with anatomopathological diagnosis. Results: forty-seven of 50 cases were confirmed, 30 by anatomopathological diagnosis. Most of then were benign lesions, hemangioma in 20%. Such lesions presented a homogeneous contrast absorption, mainly at the delayed phase, differing from malignant lesions. Metastasis was the most frequently found malignant lesion (18%). Conclusion: computed tomographic study is of great value in complementing the diagnosis of hypodense hepatic lesions in children, and must follow ultrasound diagnosis as a routine procedure. (author)

  2. Computer assisted 3D pre-operative planning tool for femur fracture orthopedic surgery

    Gamage, Pavan; Xie, Sheng Quan; Delmas, Patrice; Xu, Wei Liang

    2010-02-01

    Femur shaft fractures are caused by high impact injuries and can affect gait functionality if not treated correctly. Until recently, the pre-operative planning for femur fractures has relied on two-dimensional (2D) radiographs, light boxes, tracing paper, and transparent bone templates. The recent availability of digital radiographic equipment has to some extent improved the workflow for preoperative planning. Nevertheless, imaging is still in 2D X-rays and planning/simulation tools to support fragment manipulation and implant selection are still not available. Direct three-dimensional (3D) imaging modalities such as Computed Tomography (CT) are also still restricted to a minority of complex orthopedic procedures. This paper proposes a software tool which allows orthopedic surgeons to visualize, diagnose, plan and simulate femur shaft fracture reduction procedures in 3D. The tool utilizes frontal and lateral 2D radiographs to model the fracture surface, separate a generic bone into the two fractured fragments, identify the pose of each fragment, and automatically customize the shape of the bone. The use of 3D imaging allows full spatial inspection of the fracture providing different views through the manipulation of the interactively reconstructed 3D model, and ultimately better pre-operative planning.

  3. 3D animation of facial plastic surgery based on computer graphics

    Zhang, Zonghua; Zhao, Yan

    2013-12-01

    More and more people, especial women, are getting desired to be more beautiful than ever. To some extent, it becomes true because the plastic surgery of face was capable in the early 20th and even earlier as doctors just dealing with war injures of face. However, the effect of post-operation is not always satisfying since no animation could be seen by the patients beforehand. In this paper, by combining plastic surgery of face and computer graphics, a novel method of simulated appearance of post-operation will be given to demonstrate the modified face from different viewpoints. The 3D human face data are obtained by using 3D fringe pattern imaging systems and CT imaging systems and then converted into STL (STereo Lithography) file format. STL file is made up of small 3D triangular primitives. The triangular mesh can be reconstructed by using hash function. Top triangular meshes in depth out of numbers of triangles must be picked up by ray-casting technique. Mesh deformation is based on the front triangular mesh in the process of simulation, which deforms interest area instead of control points. Experiments on face model show that the proposed 3D animation facial plastic surgery can effectively demonstrate the simulated appearance of post-operation.

  4. Modeling tumor/polyp/lesion structure in 3D for computer-aided diagnosis in colonoscopy

    Chen, Chao-I.; Sargent, Dusty; Wang, Yuan-Fang

    2010-02-01

    We describe a software system for building three-dimensional (3D) models from colonoscopic videos. The system is end-to-end in the sense that it takes as input raw image frames-shot during a colon exam-and produces the 3D structure of objects of interest (OOI), such as tumors, polyps, and lesions. We use the structure-from-motion (SfM) approach in computer vision which analyzes an image sequence in which camera's position and aim vary relative to the OOI. The varying pose of the camera relative to the OOI induces the motion-parallax effect which allows 3D depth of the OOI to be inferred. Unlike the traditional SfM system pipeline, our software system contains many check-and-balance mechanisms to ensure robustness, and the analysis from earlier stages of the pipeline is used to guide the later processing stages to better handle challenging medical data. The constructed 3D models allow the pathology (growth and change in both structure and appearance) to be monitored over time.

  5. Parallel computation of 3-D Navier-Stokes flowfields for supersonic vehicles

    Ryan, James S.; Weeratunga, Sisira

    1993-01-01

    Multidisciplinary design optimization of aircraft will require unprecedented capabilities of both analysis software and computer hardware. The speed and accuracy of the analysis will depend heavily on the computational fluid dynamics (CFD) module which is used. A new CFD module has been developed to combine the robust accuracy of conventional codes with the ability to run on parallel architectures. This is achieved by parallelizing the ARC3D algorithm, a central-differenced Navier-Stokes method, on the Intel iPSC/860. The computed solutions are identical to those from conventional machines. Computational speed on 64 processors is comparable to the rate on one Cray Y-MP processor and will increase as new generations of parallel computers become available.

  6. Temporal bone anomalies in the branchio-oto-renal syndrome: detailed computed tomographic and magnetic resonance imaging findings.

    Ceruti, S.; Stinckens, C.I.C.; Cremers, C.W.R.J.; Casselman, J.W.

    2002-01-01

    OBJECTIVE: To inventory computed tomographic and magnetic resonance imaging findings in the branchio-oto-renal (BOR) syndrome. STUDY DESIGN: A prospective computed tomographic and magnetic resonance imaging study on a family with the BOR syndrome. SETTING: Department of medical imaging and magnetic

  7. Computed-tomographic density measurement of supersonic flow field by colored-grid background oriented schlieren (CGBOS) technique

    The background oriented schlieren (BOS) technique is one of the visualization techniques that enable the quantitative measurement of density information in the flow field with very simple experimental setup. The principle of BOS is similar to the conventional schlieren technique, which exploits the bending of light caused by refractive index change corresponding to density change in the medium and both techniques are sensible to density gradient. In this report we propose colored-grid background oriented schlieren (CGBOS) technique. The experiments were carried out in a supersonic wind tunnel of test section size 0.6 × 0.6 m2 at JAXA-ISAS. A colored-grid pattern was used as background image and density gradient in vertical and horizontal direction was obtained. Computed tomographic reconstructions of 3D density information of the supersonic flow field around an asymmetric body from multi-directional CGBOS images were examined

  8. Implementation of SceneServer : a 3D software assisting developers of computer vision algorithms

    Bennet, Fredrik; Fenelius, Stefan

    2003-01-01

    The purpose behind this thesis is to develop a software (SceneServer) that can generate data such as images and vertex lists from computer models. These models are placed in a virtual environment and they can be controlled either from a graphical user interface (GUI) or from a MATLAB client. Data can be retrieved and processed in MATLAB. By creating a connection between MATLAB and a 3D environment, computer vision algorithms can be designed and tested swiftly, thus giving the developer a powe...

  9. Computation of 3D steady Navier-Stokes flow with free-surface gravity waves

    Lewis, M. R.; Koren, Barry; Raven, H.C.

    2003-01-01

    In this paper an iterative method for the computation of stationary gravity-wave solutions is investigated, using a novel formulation of the free-surface (FS) boundary-value problem. This method requires the solution of a sequence of stationary Reynolds-Averaged Navier-Stokes subproblems employing the so-called quasi free-surface condition. The numerical performance of this new approach is investigated for two test cases. The first test case involves the computation of the 3D gravity-wave pat...

  10. New solutions and applications of 3D computer tomography image processing

    Effenberger, Ira; Kroll, Julia; Verl, Alexander

    2008-02-01

    As nowadays the industry aims at fast and high quality product development and manufacturing processes a modern and efficient quality inspection is essential. Compared to conventional measurement technologies, industrial computer tomography (CT) is a non-destructive technology for 3D-image data acquisition which helps to overcome their disadvantages by offering the possibility to scan complex parts with all outer and inner geometric features. In this paper new and optimized methods for 3D image processing, including innovative ways of surface reconstruction and automatic geometric feature detection of complex components, are presented, especially our work of developing smart online data processing and data handling methods, with an integrated intelligent online mesh reduction. Hereby the processing of huge and high resolution data sets is guaranteed. Besides, new approaches for surface reconstruction and segmentation based on statistical methods are demonstrated. On the extracted 3D point cloud or surface triangulation automated and precise algorithms for geometric inspection are deployed. All algorithms are applied to different real data sets generated by computer tomography in order to demonstrate the capabilities of the new tools. Since CT is an emerging technology for non-destructive testing and inspection more and more industrial application fields will use and profit from this new technology.

  11. A Computational Model for Suspended Large Rigid Bodies in 3D Unsteady Viscous Flows

    Xiao, Feng

    1999-11-01

    A 3D numerical model for computing large rigid objects suspended in fluid flow has been developed. Rather than calculating the surface pressure upon the solid body, we evaluate the net force and torque based on a volume force formulation. The total effective force is obtained by summing up the forces at the Eulerian grids occupied by the rigid body. The effects of the moving bodies are coupled to the fluid flow by imposing the velocity field of the bodies to the fluid. A Poisson equation is used to compute the pressure over the whole domain. The objects are identified by color functions and calculated by the PPM scheme and a tangent function transformation which scales the transition region of the computed interface to a compact thickness. The model is then implemented on a parallel computer of distributed memory and validated with Stokes and low Reynolds number flows.

  12. The current status of the development of the technology on 3D computer simulation in Japan

    The development background and property of the COSIDA, which is the 3D computer simulation system for the analysis on the dismantling procedure of the nuclear facilities in Japan was reviewed. The function of the visualization on the work area, Kinematics analysis and dismantling scenario analysis, which are the sub systems of the COSIDA, has been investigated. The physical, geometrical and radiological properties were modelled in 2D or 3D in the sub system of the visualization of the work area. In the sub system of the kinematics analysis, the command set on the basic work procedure for the control of the motion of the models at a cyber space was driven. The suitability of the command set was estimated by the application of COSIDA to the programming on the motion of the remote dismantling tools for dismantling the components of the nuclear facilities at cyber space

  13. Computational fluid dynamics simulations of blood flow regularized by 3D phase contrast MRI

    Rispoli, Vinicius C; Nielsen, Jon; Nayak, Krishna S;

    2015-01-01

    BACKGROUND: Phase contrast magnetic resonance imaging (PC-MRI) is used clinically for quantitative assessment of cardiovascular flow and function, as it is capable of providing directly-measured 3D velocity maps. Alternatively, vascular flow can be estimated from model-based computation fluid...... approach in regularizing 3D flow fields is evaluated. METHODS: The proposed algorithm incorporates both a Newtonian fluid physics model and a linear PC-MRI signal model. The model equations are solved numerically using a modified CFD algorithm. The numerical solution corresponds to the optimal solution of...... dynamics (CFD) calculations. CFD provides arbitrarily high resolution, but its accuracy hinges on model assumptions, while velocity fields measured with PC-MRI generally do not satisfy the equations of fluid dynamics, provide limited resolution, and suffer from partial volume effects. The purpose of this...

  14. Computation of Edge-Edge-Edge Events Based on Conicoid Theory for 3-D Object Recognition

    WU Chenye; MA Huimin

    2009-01-01

    The availability of a good viewpoint space partition is crucial in three dimensional (3-D) object rec-ognition on the approach of aspect graph. There are two important events depicted by the aspect graph ap-proach, edge-edge-edge (EEE) events and edge-vertex (EV) events. This paper presents an algorithm to compute EEE events by characteristic analysis based on conicoid theory, in contrast to current algorithms that focus too much on EV events and often overlook the importance of EEE events. Also, the paper provides a standard flowchart for the viewpoint space partitioning based on aspect graph theory that makes it suitable for perspective models. The partitioning result best demonstrates the algorithm's efficiency with more valu-able viewpoints found with the help of EEE events, which can definitely help to achieve high recognition rate for 3-D object recognition.

  15. Parallel Adaptive Computation of Blood Flow in a 3D ``Whole'' Body Model

    Zhou, M.; Figueroa, C. A.; Taylor, C. A.; Sahni, O.; Jansen, K. E.

    2008-11-01

    Accurate numerical simulations of vascular trauma require the consideration of a larger portion of the vasculature than previously considered, due to the systemic nature of the human body's response. A patient-specific 3D model composed of 78 connected arterial branches extending from the neck to the lower legs is constructed to effectively represent the entire body. Recently developed outflow boundary conditions that appropriately represent the downstream vasculature bed which is not included in the 3D computational domain are applied at 78 outlets. In this work, the pulsatile blood flow simulations are started on a fairly uniform, unstructured mesh that is subsequently adapted using a solution-based approach to efficiently resolve the flow features. The adapted mesh contains non-uniform, anisotropic elements resulting in resolution that conforms with the physical length scales present in the problem. The effects of the mesh resolution on the flow field are studied, specifically on relevant quantities of pressure, velocity and wall shear stress.

  16. Computed tomographic virtual cardioscopy in a case of left atrial myxoma

    Chen, H-W; Chen, S-J; Chiu, I-S

    2004-01-01

    Computed tomographic virtual cardioscopy was used to provide clear and precise visualisation of a myxoma with a stalk arising from the interatrial septum. This technique permits the safe, reliable, and non-invasive diagnosis of intracardiac lesions. This case is presented to assist the cardiovascular surgeon in preoperative planning or in developing a simulation of robotic cardiac surgery.

  17. Computed-tomographic and conventional linear-tomographic evaluation of tracheobronchial lesions for laser photoresection

    Laser therapy is a new modality for treatment of airway lesions. The authors examined 18 patients prior to laser photoresection of tracheobronchial lesions. Thirteen had cancers involving the distal trachea, carina, and/or proximal bronchi; five had benign lesions of the middle or proximal trachea. Each patient was examined by conventional linear tomography (CLT) and computed tomography (CT). CT was valuable in patients who had lesions of the distal trachea, carina, and/or proximal bronchi. Its particular usefulness, and its advantage relative to CLT, consisted in its ability to delineate vascular structures adjacent to the planned area of photoresection. Neither CLT nor CT was helpful in evaluation of benign lesions of the proximal trachea

  18. Using 2D and 3D Computer Games to Detect Colorblindness – a Comparative Study

    Laskowski Maciej

    2015-12-01

    Full Text Available Computer games have accompanied the development of computer technologies since the very beginning. Despite their basic, purely entertainment-targeted appliance, games can also be used for many other purposes. Medical applications are especially interesting, as games (especially different kinds of simulations are widely used for training personnel, e.g. to perform certain procedures or in learning to use equipment. This allows the trainees to gain knowledge and proper habits, as well as test themselves in different situations without any risk. Computer games can also be used as a diagnostic tool, although this topic is still insufficiently researched. This paper discusses the possibility of using serious games for diagnosing color vision disorders, focusing especially on two problems: differences in diagnosing colorblindness using 2D and 3D environments, and the influence of individual features, such as reflex or agility, on the diagnostic process.

  19. Computational Analysis of the Transonic Dynamics Tunnel Using FUN3D

    Chwalowski, Pawel; Quon, Eliot; Brynildsen, Scott E.

    2016-01-01

    This paper presents results from an exploratory two-year effort of applying Computational Fluid Dynamics (CFD) to analyze the empty-tunnel flow in the NASA Langley Research Center Transonic Dynamics Tunnel (TDT). The TDT is a continuous-flow, closed circuit, 16- x 16-foot slotted-test-section wind tunnel, with capabilities to use air or heavy gas as a working fluid. In this study, experimental data acquired in the empty tunnel using the R-134a test medium was used to calibrate the computational data. The experimental calibration data includes wall pressures, boundary-layer profiles, and the tunnel centerline Mach number profiles. Subsonic and supersonic flow regimes were considered, focusing on Mach 0.5, 0.7 and Mach 1.1 in the TDT test section. This study discusses the computational domain, boundary conditions, and initial conditions selected and the resulting steady-state analyses using NASA's FUN3D CFD software.

  20. Coronary computed tomography angiography with 320-row detector and using the AIDR-3D: initial experience

    Coronary computed tomography angiography (coronary CTA) is a powerful non-invasive imaging method to evaluate coronary artery disease. Nowadays, coronary CTA estimated effective radiation dose can be dramatically reduced using state-of-the-art scanners, such as 320-row detector CT (320-CT), without changing coronary CTA diagnostic accuracy. To optimize and further reduce the radiation dose, new iterative reconstruction algorithms were released recently by several CT manufacturers, and now they are used routinely in coronary CTA. This paper presents our first experience using coronary CTA with 320-CT and the Adaptive Iterative Dose Reduction 3D (AIDR-3D). In addition, we describe the current indications for coronary CTA in our practice as well as the acquisition standard protocols and protocols related to CT application for radiation dose reduction. In conclusion, coronary CTA radiation dose can be dramatically reduced following the 'as low as reasonable achievable' principle by combination of exam indication and well-documented technics for radiation dose reduction, such as beta blockers, low-kV, and also the newest iterative dose reduction software as AIDR-3D. (author)

  1. Traveltime computation and imaging from rugged topography in 3D TTI media

    Foothill areas with rugged topography are of great potential for oil and gas seismic exploration, but subsurface imaging in these areas is very challenging. Seismic acquisition with larger offset and wider azimuth is necessary for seismic imaging in complex areas. However, the scale anisotropy in this case must be taken into account. To generalize the pre-stack depth migration (PSDM) to 3D transversely isotropic media with vertical symmetry axes (VTI) and tilted symmetry axes (TTI) from rugged topography, a new dynamic programming approach for the first-arrival traveltime computation method is proposed. The first-arrival time on every uniform mesh point is calculated based on Fermat's principle with simple calculus techniques and a systematic mapping scheme. In order to calculate the minimum traveltime, a set of nonlinear equations is solved on each mesh point, where the group velocity is determined by the group angle. Based on the new first-arrival time calculation method, the corresponding PSDM and migration velocity analysis workflow for 3D anisotropic media from rugged surface is developed. Numerical tests demonstrate that the proposed traveltime calculation method is effective in both VTI and TTI media. The migration results for 3D field data show that it is necessary to choose a smooth datum to remove the high wavenumber move-out components for PSDM with rugged topography and take anisotropy into account to achieve better images. (paper)

  2. Coupled fully 3D neutron kinetics thermal-hydraulic computations for DNB analysis on PWRs

    Departure from Nucleate Boiling (DNB) is one of the major limiting factors of Pressurized Water Reactors (PWRs). Safety requires that occurrence of DNB should be precluded under normal or incidental operating conditions. To perform Main Steam Line Break (MSLB) accident calculations EDF have developed its own numerical tool OSCARD based on: the thermal-hydraulic THYC code for DNB analysis, the neutron kinetics COCCINELLE code for power distribution computations, the thermal-hydraulic CATHARE code to provide boundary conditions analysis with system scale computation. With OSCARD a fully three-dimensional (3D) representation of the core is proposed in conjunction with a two-phase flow porous-body approach (THYC) and two-group diffusion equations in the axial and lateral directions with Doppler and void reactivity feedback effects (COCCINELLE). OSCARD provides EDF with an alternative and independent way of evaluating fuel performance and safety margins. In the licensed approach, the coupled 3D neutron kinetics and thermal-hydraulic part of OSCARD steady computations is used to produce 3D power distribution in the reactor core at the most penalizing moment of the transient. Then this distribution is used as an input for THYC to perform thermal-hydraulic subchannel analysis. This 3 steps approach is used with simple conservative and bounding analysis assumptions, that can not occur in reality. In a prospective approach, OSCARD enables to combine thermal-hydraulic subchannel analysis with the neutron kinetics radial average channel model using a nodalization of one quarter of fuel assembly in order to perform one step DNB analysis. (author)

  3. 3-D electromagnetic plasma particle simulations on the Intel Delta parallel computer

    A three-dimensional electromagnetic PIC code has been developed on the 512 node Intel Touchstone Delta MIMD parallel computer. This code is based on the General Concurrent PIC algorithm which uses a domain decomposition to divide the computation among the processors. The 3D simulation domain can be partitioned into 1-, 2-, or 3-dimensional sub-domains. Particles must be exchanged between processors as they move among the subdomains. The Intel Delta allows one to use this code for very-large-scale simulations (i.e. over 108 particles and 106 grid cells). The parallel efficiency of this code is measured, and the overall code performance on the Delta is compared with that on Cray supercomputers. It is shown that their code runs with a high parallel efficiency of ≥ 95% for large size problems. The particle push time achieved is 115 nsecs/particle/time step for 162 million particles on 512 nodes. Comparing with the performance on a single processor Cray C90, this represents a factor of 58 speedup. The code uses a finite-difference leap frog method for field solve which is significantly more efficient than fast fourier transforms on parallel computers. The performance of this code on the 128 node Cray T3D will also be discussed

  4. Development of a system for 3D reconstruction of objects using passive computer vision methods

    Gec, Sandi

    2015-01-01

    The main goal of the master thesis is to develop a system for reconstruction of 3D objects from colour images. The main focus is on passive computer vision methods from which we select two, i.e., Stereo vision and Space carving. Both methods require information about camera poses. The camera pose for a given image is estimated from the information obtained by detecting a reference object, i.e., a standard A4 paper sheet. We develop an Android based mobile application to guide a user during im...

  5. The history of visual magic in computers how beautiful images are made in CAD, 3D, VR and AR

    Peddie, Jon

    2013-01-01

    If you have ever looked at a fantastic adventure or science fiction movie, or an amazingly complex and rich computer game, or a TV commercial where cars or gas pumps or biscuits behaved liked people and wondered, ""How do they do that?"",  then you've experienced the magic of 3D worlds generated by a computer.3D in computers began as a way to represent automotive designs and illustrate the construction of molecules. 3D graphics use evolved to visualizations of simulated data and artistic representations of imaginary worlds. In order to overcome the processing limitations of the computer, graph

  6. Reducing computational costs in large scale 3D EIT by using a sparse Jacobian matrix with block-wise CGLS reconstruction

    Electrical impedance tomography (EIT) is a fast and cost-effective technique to provide a tomographic conductivity image of a subject from boundary current–voltage data. This paper proposes a time and memory efficient method for solving a large scale 3D EIT inverse problem using a parallel conjugate gradient (CG) algorithm. The 3D EIT system with a large number of measurement data can produce a large size of Jacobian matrix; this could cause difficulties in computer storage and the inversion process. One of challenges in 3D EIT is to decrease the reconstruction time and memory usage, at the same time retaining the image quality. Firstly, a sparse matrix reduction technique is proposed using thresholding to set very small values of the Jacobian matrix to zero. By adjusting the Jacobian matrix into a sparse format, the element with zeros would be eliminated, which results in a saving of memory requirement. Secondly, a block-wise CG method for parallel reconstruction has been developed. The proposed method has been tested using simulated data as well as experimental test samples. Sparse Jacobian with a block-wise CG enables the large scale EIT problem to be solved efficiently. Image quality measures are presented to quantify the effect of sparse matrix reduction in reconstruction results. (paper)

  7. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals’ Behaviour

    Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola

    2016-01-01

    Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs’ behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals’ quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog’s shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non

  8. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.

    Shanis Barnard

    Full Text Available Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is

  9. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.

    Barnard, Shanis; Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola

    2016-01-01

    Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non

  10. Computer-controlled dynamic mode multidirectional UV lithography for 3D microfabrication

    Computer-controlled dynamic mode multidirectional ultraviolet (UV) lithography has been demonstrated using a collimated UV light source, a substrate-holding stage equipped with two stepper motors (one for tilting and the other for rotation), a controller with programming software and a laptop computer. The tilting and rotational angles of the stage in motion are accurately controlled during UV exposure as programmed by the user to produce complex three-dimensional (3D) microstructures. Process parameters include the initial and final tilting and rotational angles of the stage, and the relative angular velocities of the two motors in addition to the normal fabrication process parameters of UV lithography such as optical dose, baking time, and developing time and condition. Symmetric patterns can be generated by a simple synchronous mode dynamic operation, where both the angular velocities of the tilting motion and the rotating motion are set equal or harmonically related. More complex and non-symmetric patterns can be obtained using a piecewise synchronous mode, where the relationship between the angular velocities of the two motors is described not with a single coefficient but with a set of coefficients. 3D structures fabricated from the synchronous mode operation include the four-leaf clover horn and the cardiac horn while the ones from the piecewise synchronous mode are a vertical triangular slab, a screwed wind vane and arbitrary shape horns. Ray trace simulation has been performed using a mathematical tool in a spherical coordinate system and the simulated 3D patterns show good agreement with the fabricated ones.