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1

3D biopsy for tomosynthesis: simulation of prior information based reconstruction for dose and artifact reduction  

Science.gov (United States)

Accurately targeting of small lesions for success is crucial in breast biopsy. In this paper, we proposed a new 3D tomobased biopsy, which is characterized in being more accurate, easier to perform, lower in dose, and free of metal artifact. In the scout phase, a conventional tomosynthesis scan is performed, and the reconstructed 3D image is then used for radiologists to accurately localize target volume and determine optimized needle path. In the prefire phase, two prefire stereotactic images are obtained at +24° and -24° angular levels for retrieving needle and shifted lesion locations. By combining the reconstructed 3D tomosynthesis image, needle location and lesion location, synthetic prefire and postfire images are generated for radiologists' reference before firing the real needle. The proposed scheme not only improves the biopsy accuracy but also reduces dose by 3.7-5.6 times compared to conventional mammo-based stereotactic biopsy. A simulation using anthropomorphic phantom was conducted to verify our method. Both needle and lesion were precisely recovered just based on two tomo angled images. For the needle registration, the sum of translation discrepancy is less than 3 pixels, and the sum of rotation discrepancy is less than 3 degrees. For the lesion registration, the sum of coordinate discrepancy is less than 4 pixels. The predicted 3D prefire and postfire images exhibited more intuitive spatial relationship of the shifted lesion and biopsy needle tip than mammo-based stereotactic biopsy.

Lin, Yuan; Ghate, Sujata; Lo, Joseph; Samei, Ehsan

2012-02-01

2

Reconstruction-independent 3D CAD for mass detection in digital breast tomosynthesis using fuzzy particles  

Science.gov (United States)

In this paper we present a novel approach for mass detection in Digital Breast Tomosynthesis (DBT) datasets. A reconstruction-independent approach, working directly on the projected views, is proposed. Wavelet filter responses on the projections are thresholded and combined to obtain candidate masses. For each candidate, we create a fuzzy contour through a multi-level thresholding process. We introduce a fuzzy set definition for the class mass contour that allows the computation of fuzzy membership values for each candidate contour. Then, an aggregation operator is presented that combines information over the complete set of projected views, resulting in 3D fuzzy particles. A final decision is made taking into account all available information. The performance of the presented algorithm was evaluated on a database of 11 one-breast-cases resulting in a sensitivity (Se) of 0.86 and a false positive rate (FPR) of 3.5 per case.

Peters, G.; Muller, S.; Bernard, S.; Iordache, R.; Bloch, I.

2006-03-01

3

Inter-plane artifact suppression in tomosynthesis using 3D CT image data  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Despite its superb lateral resolution, flat-panel-detector (FPD based tomosynthesis suffers from low contrast and inter-plane artifacts caused by incomplete cancellation of the projection components stemming from outside the focal plane. The incomplete cancellation of the projection components, mostly due to the limited scan angle in the conventional tomosynthesis scan geometry, often makes the image contrast too low to differentiate the malignant tissues from the background tissues with confidence. Methods In this paper, we propose a new method to suppress the inter-plane artifacts in FPD-based tomosynthesis. If 3D whole volume CT images are available before the tomosynthesis scan, the CT image data can be incorporated into the tomosynthesis image reconstruction to suppress the inter-plane artifacts, hence, improving the image contrast. In the proposed technique, the projection components stemming from outside the region-of-interest (ROI are subtracted from the measured tomosynthesis projection data to suppress the inter-plane artifacts. The projection components stemming from outside the ROI are calculated from the 3D whole volume CT images which usually have lower lateral resolution than the tomosynthesis images. The tomosynthesis images are reconstructed from the subtracted projection data which account for the x-ray attenuation through the ROI. After verifying the proposed method by simulation, we have performed both CT scan and tomosynthesis scan on a phantom and a sacrificed rat using a FPD-based micro-CT. Results We have measured contrast-to-noise ratio (CNR from the tomosynthesis images which is an indicator of the residual inter-plane artifacts on the focal-plane image. In both cases of the simulation and experimental imaging studies of the contrast evaluating phantom, CNRs have been significantly improved by the proposed method. In the rat imaging also, we have observed better visual contrast from the tomosynthesis images reconstructed by the proposed method. Conclusions The proposed tomosynthesis technique can improve image contrast with aids of 3D whole volume CT images. Even though local tomosynthesis needs extra 3D CT scanning, it may find clinical applications in special situations in which extra 3D CT scan is already available or allowed.

Kim Jae G

2011-12-01

4

The simulation of 3D microcalcification clusters in 2D digital mammography and breast tomosynthesis  

Energy Technology Data Exchange (ETDEWEB)

Purpose: This work proposes a new method of building 3D models of microcalcification clusters and describes the validation of their realistic appearance when simulated into 2D digital mammograms and into breast tomosynthesis images. Methods: A micro-CT unit was used to scan 23 breast biopsy specimens of microcalcification clusters with malignant and benign characteristics and their 3D reconstructed datasets were segmented to obtain 3D models of microcalcification clusters. These models were then adjusted for the x-ray spectrum used and for the system resolution and simulated into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. Six radiologists were asked to distinguish between 40 real and 40 simulated clusters of microcalcifications in two separate studies on 2D mammography and tomosynthesis datasets. Receiver operating characteristic (ROC) analysis was used to test the ability of each observer to distinguish between simulated and real microcalcification clusters. The kappa statistic was applied to assess how often the individual simulated and real microcalcification clusters had received similar scores (''agreement'') on their realistic appearance in both modalities. This analysis was performed for all readers and for the real and the simulated group of microcalcification clusters separately. ''Poor'' agreement would reflect radiologists' confusion between simulated and real clusters, i.e., lesions not systematically evaluated in both modalities as either simulated or real, and would therefore be interpreted as a success of the present models. Results: The area under the ROC curve, averaged over the observers, was 0.55 (95% confidence interval [0.44, 0.66]) for the 2D study, and 0.46 (95% confidence interval [0.29, 0.64]) for the tomosynthesis study, indicating no statistically significant difference between real and simulated lesions (p > 0.05). Agreement between allocated lesion scores for 2D mammography and those for the tomosynthesis series was poor. Conclusions: The realistic appearance of the 3D models of microcalcification clusters, whether malignant or benign clusters, was confirmed for 2D digital mammography images and the breast tomosynthesis datasets; this database of clusters is suitable for use in future observer performance studies related to the detectability of microcalcification clusters. Such studies include comparing 2D digital mammography to breast tomosynthesis and comparing different reconstruction algorithms.

Shaheen, Eman; Van Ongeval, Chantal; Zanca, Federica; Cockmartin, Lesley; Marshall, Nicholas; Jacobs, Jurgen; Young, Kenneth C.; Dance, David R.; Bosmans, Hilde [Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford, GU2 7XX (United Kingdom); Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium)

2011-12-15

5

3D heart reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this thesis was to achieve a 3D reconstruction of the four heart chambers using 2D echocardiographic images. A level set algorithm based on the phase symmetry approach and on a new logarithmic based stopping function was used to extract simultaneously the four heart cavities from these images in a fully automatic way. However to proceed to the 3D reconstruction using the segmented images, it was first necessary to satisfy clinical practise requirements. This means that the algo...

2011-01-01

6

Application of boundary detection information in breast tomosynthesis reconstruction  

International Nuclear Information System (INIS)

Digital tomosynthesis mammography (DTM) is one of the most promising techniques that can potentially improve early detection of breast cancers. DTM can provide three-dimensional (3D) structural information by reconstructing the whole imaged volume from a sequence of projection-view (PV) mammograms that are acquired at a small number of projection angles over a limited angular range. Our previous study showed that simultaneous algebraic reconstruction technique (SART) can produce satisfactory tomosynthesized image quality compared to maximum likelihood-type algorithms. To improve the efficiency of DTM reconstruction and address the problem of boundary artifacts, we have developed methods to incorporate both two-dimensional (2D) and 3D breast boundary information within the SART reconstruction algorithm in this study. A second generation GE prototype tomosynthesis mammography system with a stationary digital detector was used for PV image acquisition from 21 angles in 3 deg. increments over a ±30 deg. angular range. The 2D breast boundary curves on all PV images were obtained by automated segmentation and were used to restrict the SART reconstruction to be performed only within the breast volume. The computation time of SART reconstruction was reduced by 76.3% and 69.9% for cranio-caudal and mediolateral oblique views, respectively, for the chosen example. In addition, a 3D conical trimming method was developed in which the 2D breast boundary curves from all PVs were back projected to generate the 3D breast surface. This 3D surface was then used to eliminate the multiple breast shadows outside the breast volume due to reconstruction by setting these voxels to a constant background value. Our study demonstrates that, by using the 2D and 3D breast boundary information, all breast boundary and most detector boundary artifacts can be effectively removed on all tomosynthesized slices

2007-09-01

7

Oblique reconstructions in tomosynthesis. II. Super-resolution  

Energy Technology Data Exchange (ETDEWEB)

Purpose: In tomosynthesis, super-resolution has been demonstrated using reconstruction planes parallel to the detector. Super-resolution allows for subpixel resolution relative to the detector. The purpose of this work is to develop an analytical model that generalizes super-resolution to oblique reconstruction planes.Methods: In a digital tomosynthesis system, a sinusoidal test object is modeled along oblique angles (i.e., “pitches”) relative to the plane of the detector in a 3D divergent-beam acquisition geometry. To investigate the potential for super-resolution, the input frequency is specified to be greater than the alias frequency of the detector. Reconstructions are evaluated in an oblique plane along the extent of the object using simple backprojection (SBP) and filtered backprojection (FBP). By comparing the amplitude of the reconstruction against the attenuation coefficient of the object at various frequencies, the modulation transfer function (MTF) is calculated to determine whether modulation is within detectable limits for super-resolution. For experimental validation of super-resolution, a goniometry stand was used to orient a bar pattern phantom along various pitches relative to the breast support in a commercial digital breast tomosynthesis system.Results: Using theoretical modeling, it is shown that a single projection image cannot resolve a sine input whose frequency exceeds the detector alias frequency. The high frequency input is correctly visualized in SBP or FBP reconstruction using a slice along the pitch of the object. The Fourier transform of this reconstructed slice is maximized at the input frequency as proof that the object is resolved. Consistent with the theoretical results, experimental images of a bar pattern phantom showed super-resolution in oblique reconstructions. At various pitches, the highest frequency with detectable modulation was determined by visual inspection of the bar patterns. The dependency of the highest detectable frequency on pitch followed the same trend as the analytical model. It was demonstrated that super-resolution is not achievable if the pitch of the object approaches 90°, corresponding to the case in which the test frequency is perpendicular to the breast support. Only low frequency objects are detectable at pitches close to 90°.Conclusions: This work provides a platform for investigating super-resolution in oblique reconstructions for tomosynthesis. In breast imaging, this study should have applications in visualizing microcalcifications and other subtle signs of cancer.

Acciavatti, Raymond J.; Maidment, Andrew D. A. [Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-4206 (United States)

2013-11-15

8

Simulation of 3D objects into breast tomo-synthesis images  

International Nuclear Information System (INIS)

Digital breast tomo-synthesis is a new three-dimensional (3D) breast-imaging modality that produces images of cross-sectional planes parallel to the detector plane from a limited number of X-ray projections over a limited angular range. Several technical and clinical parameters have not yet been completely optimised. Some of the open questions could be addressed experimentally; other parameter settings cannot be easily realised in practice and the associated optimisation process requires therefore a theoretical approach. Rather than simulating the complete 3D imaging chain, it is hypothesised that the simulation of small lesions into clinical (or test object) images can be of help in the optimisation process. In the present study, small 3D objects have been simulated into real projection images. Subsequently, these hybrid projection images are reconstructed using the routine clinical reconstruction tools. In this study, the validation of this simulation framework is reported through the comparison between simulated and real objects in reconstructed planes. The results confirm that there is no statistically significant difference between the simulated and the real objects. This suggests that other small mathematical or physiological objects could be simulated with the same approach. (authors)

2009-06-25

9

Optimized image acquisition for breast tomosynthesis in projection and reconstruction space  

Energy Technology Data Exchange (ETDEWEB)

Breast tomosynthesis has been an exciting new development in the field of breast imaging. While the diagnostic improvement via tomosynthesis is notable, the full potential of tomosynthesis has not yet been realized. This may be attributed to the dependency of the diagnostic quality of tomosynthesis on multiple variables, each of which needs to be optimized. Those include dose, number of angular projections, and the total angular span of those projections. In this study, the authors investigated the effects of these acquisition parameters on the overall diagnostic image quality of breast tomosynthesis in both the projection and reconstruction space. Five mastectomy specimens were imaged using a prototype tomosynthesis system. 25 angular projections of each specimen were acquired at 6.2 times typical single-view clinical dose level. Images at lower dose levels were then simulated using a noise modification routine. Each projection image was supplemented with 84 simulated 3 mm 3D lesions embedded at the center of 84 nonoverlapping ROIs. The projection images were then reconstructed using a filtered backprojection algorithm at different combinations of acquisition parameters to investigate which of the many possible combinations maximizes the performance. Performance was evaluated in terms of a Laguerre-Gauss channelized Hotelling observer model-based measure of lesion detectability. The analysis was also performed without reconstruction by combining the model results from projection images using Bayesian decision fusion algorithm. The effect of acquisition parameters on projection images and reconstructed slices were then compared to derive an optimization rule for tomosynthesis. The results indicated that projection images yield comparable but higher performance than reconstructed images. Both modes, however, offered similar trends: Performance improved with an increase in the total acquisition dose level and the angular span. Using a constant dose level and angular span, the performance rolled off beyond a certain number of projections, indicating that simply increasing the number of projections in tomosynthesis may not necessarily improve its performance. The best performance for both projection images and tomosynthesis slices was obtained for 15-17 projections spanning an angular arc of {approx}45 deg. - the maximum tested in our study, and for an acquisition dose equal to single-view mammography. The optimization framework developed in this framework is applicable to other reconstruction techniques and other multiprojection systems.

Chawla, Amarpreet S.; Lo, Joseph Y.; Baker, Jay A.; Samei, Ehsan [Department of Radiology and Department of Biomedical Engineering, Duke Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Department of Medical Physics, and Department of Biomedical Engineering, Duke Advanced Imaging Laboratories, Duke University Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Durham, North Carolina 27705 (United States); Department of Radiology, Department of Medical Physics, and Department of Biomedical Engineering, Duke Advanced Imaging Laboratories, Duke University Durham, North Carolina 27705 (United States)

2009-11-15

10

3D statistical facial reconstruction  

CERN Document Server

The aim of craniofacial reconstruction is to produce a likeness of a face from the skull. Few works in computerized assisted facial reconstruction have been done in the past, due to poor machine performances and data availability, and major works are manually reconstructions. In this paper, we present an approach to build 3D statistical models of the skull and the face with soft tissues from the skull of one individual. Results on real data are presented and seem promising.

Berar, M; Bailly, G; Payan, Y; Berar, Maxime; Desvignes, Michel; Payan, Yohan

2005-01-01

11

Digital breast tomosynthesis reconstruction with an adaptive voxel grid  

Science.gov (United States)

In digital breast tomosynthesis (DBT) volume datasets are typically reconstructed with an anisotropic voxel size, where the in-plane voxel size usually reflects the detector pixel size (e.g., 0.1 mm), and the slice separation is generally between 0.5-1.0 mm. Increasing the tomographic angle is expected to give better 3D image quality; however, the slice spacing in the reconstruction should be reduced, otherwise one may risk losing fine-scale image detail (e.g., small microcalcifications). An alternative strategy consists of reconstructing on an adaptive voxel grid, where the voxel height at each location is adapted based on the backprojected data at this location, with the goal to improve image quality for microcalcifications. In this paper we present an approach for generating such an adaptive voxel grid. This approach is based on an initial reconstruction step that is performed at a finer slice-spacing combined with a selection of an "optimal" height for each voxel. This initial step is followed by a (potentially iterative) reconstruction acting now on the adaptive grid only.

Claus, Bernhard; Chan, Heang-Ping

2014-03-01

12

A novel approach to digital breast tomosynthesis for simultaneous acquisition of 2D and 3D images  

International Nuclear Information System (INIS)

The complexity of anatomical structure within the breast represents the ultimate limit to signal detection on a mammogram. To increase lesion conspicuity Digital Breast Tomosynthesis (DBT) has been recently proposed and several manufacturers are currently performing clinical trials. In this study we investigate the potential of DBT with variable dose distribution by using a phantom in which details of interest are within a heterogeneous background. To compare the performance of a commercial digital mammography unit and a DBT prototype, 2D and 3D images of the breast phantom were obtained at similar dose levels. As expected, DBT showed superior performance over digital mammography. Although certain details of interest are not detectable with digital mammography, DBT can reveal their signal by reducing the complexity of tissue structures. Additionally, the potential of the central projection in variable dose DBT is similar to the standard projection obtained with digital mammography. Finally, the uniform and variable dose approaches provided almost identical reconstructed slices. This preliminary investigation demonstrates that breast tomosynthesis acquired with variable dose distribution exhibits inherent 3D reconstruction advantages for structure noise removal and provides a 2D projection with a physical image quality close to that of standard mammography. (orig.)

2011-06-01

13

Comparison of reconstruction algorithms for digital breast tomosynthesis  

CERN Multimedia

Digital breast tomosynthesis (DBT) is an emerging modality for breast imaging. A typical tomosynthesis image is reconstructed from projection data acquired at a limited number of views over a limited angular range. In general, the quantitative accuracy of the image can be significantly compromised by severe artifacts and non-isotropic resolution resulting from the incomplete data. Nevertheless, it has been demonstrated that DBT may yield useful information for detection/classification tasks and thus is considered a promising breast imaging modality currently undergoing pre-clinical evaluation trials. The purpose of this work is to conduct a preliminary, but systematic, investigation and evaluation of the properties of reconstruction algorithms that have been proposed for DBT. We use a breast phantom designed for DBT evaluation to generate analytic projection data for a typical DBT configuration, which is currently undergoing pre-clinical evaluation. The reconstruction algorithms under comparison include (i) f...

Reiser, I; Nishikawa, R M; Sidky, E Y; Pan, X

2009-01-01

14

A task-based comparison of two reconstruction algorithms for digital breast tomosynthesis  

Science.gov (United States)

Digital breast tomosynthesis (DBT) generates 3-D reconstructions of the breast by taking X-Ray projections at various angles around the breast. DBT improves cancer detection as it minimizes tissue overlap that is present in traditional 2-D mammography. In this work, two methods of reconstruction, filtered backprojection (FBP) and the Newton-Raphson iterative reconstruction were used to create 3-D reconstructions from phantom images acquired on a breast tomosynthesis system. The task based image analysis method was used to compare the performance of each reconstruction technique. The task simulated a 10mm lesion within the breast containing iodine concentrations between 0.0mg/ml and 8.6mg/ml. The TTF was calculated using the reconstruction of an edge phantom, and the NPS was measured with a structured breast phantom (CIRS 020) over different exposure levels. The detectability index d' was calculated to assess image quality of the reconstructed phantom images. Image quality was assessed for both conventional, single energy and dual energy subtracted reconstructions. Dose allocation between the high and low energy scans was also examined. Over the full range of dose allocations, the iterative reconstruction yielded a higher detectability index than the FBP for single energy reconstructions. For dual energy subtraction, detectability index was maximized when most of the dose was allocated to the high energy image. With that dose allocation, the performance trend for reconstruction algorithms reversed; FBP performed better than the corresponding iterative reconstruction. However, FBP performance varied very erratically with changing dose allocation. Therefore, iterative reconstruction is preferred for both imaging modalities despite underperforming dual energy FBP, as it provides stable results.

Mahadevan, Ravi; Ikejimba, Lynda C.; Lin, Yuan; Samei, Ehsan; Lo, Joseph Y.

2014-03-01

15

Automatic Reconstruction of Textured 3D Models  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The digital recreation of environments is an increasingly important task and there are many application areas where 3D models are required. This thesis addresses the problem of automatic 3D reconstruction and we present a system for unsupervised reconstruction of textured 3D models in the context of modeling indoor environments. The contributions are solutions to all aspects of the modeling process and an integrated system for the automatic creation of large-scale 3D models.

Pitzer, Benjamin

2012-01-01

16

Comparison of power spectra for tomosynthesis projections and reconstructed images  

International Nuclear Information System (INIS)

Burgess et al. [Med. Phys. 28, 419-437 (2001)] showed that the power spectrum of mammographic breast background follows a power law and that lesion detectability is affected by the power-law exponent ? which measures the amount of structure in the background. Following the study of Burgess et al., the authors measured and compared the power-law exponent of mammographic backgrounds in tomosynthesis projections and reconstructed slices to investigate the effect of tomosynthesis imaging on background structure. Our data set consisted of 55 patient cases. For each case, regions of interest (ROIs) were extracted from both projection images and reconstructed slices. The periodogram of each ROI was computed by taking the squared modulus of the Fourier transform of the ROI. The power-law exponent was determined for each periodogram and averaged across all ROIs extracted from all projections or reconstructed slices for each patient data set. For the projections, the mean ? averaged across the 55 cases was 3.06 (standard deviation of 0.21), while it was 2.87 (0.24) for the corresponding reconstructions. The difference in ? for a given patient between the projection ROIs and the reconstructed ROIs averaged across the 55 cases was 0.194, which was statistically significant (p<0.001). The 95% CI for the difference between the mean value of ? for the projections and reconstructions was [0.170, 0.218]. The results are consistent with the observation that the amount of breast structure in the tomosynthesis slice is reduced compared to projection mammography and that this may lead to improved lesion detectability.

2009-05-01

17

Numerical Methods for Coupled Reconstruction and Registration in Digital Breast Tomosynthesis  

CERN Multimedia

Digital Breast Tomosynthesis (DBT) provides an insight into the fine details of normal fibroglandular tissues and abnormal lesions by reconstructing a pseudo-3D image of the breast. In this respect, DBT overcomes a major limitation of conventional X-ray mammography by reducing the confounding effects caused by the superposition of breast tissue. In a breast cancer screening or diagnostic context, a radiologist is interested in detecting change, which might be indicative of malignant disease. To help automate this task image registration is required to establish spatial correspondence between time points. Typically, images, such as MRI or CT, are first reconstructed and then registered. This approach can be effective if reconstructing using a complete set of data. However, for ill-posed, limited-angle problems such as DBT, estimating the deformation is complicated by the significant artefacts associated with the reconstruction, leading to severe inaccuracies in the registration. This paper presents a mathemati...

Yang, Guang; Hawkes, David J; Arridge, Simon R

2013-01-01

18

Convergence of iterative image reconstruction algorithms for Digital Breast Tomosynthesis  

DEFF Research Database (Denmark)

Most iterative image reconstruction algorithms are based on some form of optimization, such as minimization of a data-fidelity term plus an image regularizing penalty term. While achieving the solution of these optimization problems may not directly be clinically relevant, accurate optimization solutions can aid in iterative image reconstruction algorithm design. This issue is particularly acute for iterative image reconstruction in Digital Breast Tomosynthesis (DBT), where the corresponding data model IS particularly poorly conditioned. The impact of this poor conditioning is that iterative algorithms applied to this system can be slow to converge. Recent developments in first-order algorithms are now beginning to allow for accurate solutions to optimization problems of interest to tomographic imaging in general. In particular, we investigate an algorithm developed by Chambolle and Pock (2011 J. Math. Imag. Vol. 40, pgs 120-145) and apply it to iterative image reconstruction in DBT.

Jørgensen, Jakob Heide

2012-01-01

19

Forensic 3D Scene Reconstruction  

International Nuclear Information System (INIS)

Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene

1999-01-01

20

Forensic 3D Scene Reconstruction  

Energy Technology Data Exchange (ETDEWEB)

Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

1999-10-12

 
 
 
 
21

Accelerating reconstruction of reference digital tomosynthesis using graphics hardware  

International Nuclear Information System (INIS)

The successful implementation of digital tomosynthesis (DTS) for on-board image guided radiation therapy (IGRT) requires fast DTS image reconstruction. Both target and reference DTS image sets are required to support an image registration application for IGRT. Target images are usually DTS image sets reconstructed from on-board projections, which can be accomplished quickly using the conventional filtered backprojection algorithm. Reference images are DTS image sets reconstructed from digitally reconstructed radiographs (DRRs) previously generated from conventional planning CT data. Generating a set of DRRs from planning CT is relatively slow using the conventional ray-casting algorithm. In order to facilitate DTS reconstruction within a clinically acceptable period of time, we implemented a high performance DRR reconstruction algorithm on a graphics processing unit of commercial PC graphics hardware. The performance of this new algorithm was evaluated and compared with that which is achieved using the conventional software-based ray-casting algorithm. DTS images were reconstructed from DRRs previously generated by both hardware and software algorithms. On average, the DRR reconstruction efficiency using the hardware method is improved by a factor of 67 over the software method. The image quality of the DRRs was comparable to those generated using the software-based ray-casting algorithm. Accelerated DRR reconstruction significantly reduces the overall time required to produce a set of reference DTS images from planning CT and makes this technique clinically practical for target localization for radiation therapy

2007-10-01

22

3D reconstruction of six mandibular canines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Six extracted mandibular canines were reconstructed three-dimensionally, in order to demonstrate their external and internal morphological and anatomical features and to determine the number and ramifications of their root canals. The process of the 3D reconstruction included serial cross-sectioning, digitization of the sections, extraction of the boundaries from each tooth, 3D representation by using the triangulation method and finally surface rendering by using photorealistic effects. The ...

Lyroudia, K.; Dourou, V.; Digka, A.; Pitas, I.

2010-01-01

23

3D Reconstruction of NMR Images  

Directory of Open Access Journals (Sweden)

Full Text Available This paper introduces experiment of 3D reconstruction NMR images scanned from magnetic resonance device. There are described methods which can be used for 3D reconstruction magnetic resonance images in biomedical application. The main idea is based on marching cubes algorithm. For this task was chosen sophistication method by program Vision Assistant, which is a part of program LabVIEW.

Peter Izak

2007-01-01

24

A 3D linear system model for the optimization of dual-energy contrast-enhanced digital breast tomosynthesis  

Science.gov (United States)

Digital breast tomosynthesis (DBT) is a three-dimensional (3D) x-ray imaging modality that has been shown to decrease the obscuring effect of breast structural noise, thereby increasing lesion conspicuity. To further improve breast cancer detection, much recent work has been devoted to the development of contrast enhanced DBT (CEDBT). Taking advantage of angiogenesis in malignant tissue, CEDBT involves the injection of radio-opaque material (i.e. iodine) and measures the relative increase in uptake of contrast in breast cancer. Either temporal or dual energy subtraction techniques may be used to implement CEDBT. Our present work is to develop a cascaded linear system model for DBT with a CEDBT option to calculate the ideal observer signal to noise ratio (SNR) of lesions in the presence of structural noise, evaluate the efficacy of CEDBT in the removal of structural noise, and examine the associated increase in x-ray quantum noise. Our model will include the effects of dual energy subtraction on signal and noise transfer, and transfer of power-law form anatomical noise through a DBT system using a modified filtered backprojection (FBP) algorithm. This model will be used for the optimization of x-ray techniques and reconstruction filters in CEDBT.

Hu, Yue-Houng; Zhao, Wei

2011-03-01

25

Reproducibility of 3D chromatin configuration reconstructions.  

Science.gov (United States)

It is widely recognized that the three-dimensional (3D) architecture of eukaryotic chromatin plays an important role in processes such as gene regulation and cancer-driving gene fusions. Observing or inferring this 3D structure at even modest resolutions had been problematic, since genomes are highly condensed and traditional assays are coarse. However, recently devised high-throughput molecular techniques have changed this situation. Notably, the development of a suite of chromatin conformation capture (CCC) assays has enabled elicitation of contacts-spatially close chromosomal loci-which have provided insights into chromatin architecture. Most analysis of CCC data has focused on the contact level, with less effort directed toward obtaining 3D reconstructions and evaluating the accuracy and reproducibility thereof. While questions of accuracy must be addressed experimentally, questions of reproducibility can be addressed statistically-the purpose of this paper. We use a constrained optimization technique to reconstruct chromatin configurations for a number of closely related yeast datasets and assess reproducibility using four metrics that measure the distance between 3D configurations. The first of these, Procrustes fitting, measures configuration closeness after applying reflection, rotation, translation, and scaling-based alignment of the structures. The others base comparisons on the within-configuration inter-point distance matrix. Inferential results for these metrics rely on suitable permutation approaches. Results indicate that distance matrix-based approaches are preferable to Procrustes analysis, not because of the metrics per se but rather on account of the ability to customize permutation schemes to handle within-chromosome contiguity. It has recently been emphasized that the use of constrained optimization approaches to 3D architecture reconstruction are prone to being trapped in local minima. Our methods of reproducibility assessment provide a means for comparing 3D reconstruction solutions so that we can discern between local and global optima by contrasting solutions under perturbed inputs. PMID:24519450

Segal, Mark R; Xiong, Hao; Capurso, Daniel; Vazquez, Mariel; Arsuaga, Javier

2014-07-01

26

The PRISM3D paleoenvironmental reconstruction  

Science.gov (United States)

The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) paleoenvironmental reconstruction is an internally consistent and comprehensive global synthesis of a past interval of relatively warm and stable climate. It is regularly used in model studies that aim to better understand Pliocene climate, to improve model performance in future climate scenarios, and to distinguish model-dependent climate effects. The PRISM reconstruction is constantly evolving in order to incorporate additional geographic sites and environmental parameters, and is continuously refined by independent research findings. The new PRISM three dimensional (3D) reconstruction differs from previous PRISM reconstructions in that it includes a subsurface ocean temperature reconstruction, integrates geochemical sea surface temperature proxies to supplement the faunal-based temperature estimates, and uses numerical models for the first time to augment fossil data. Here we describe the components of PRISM3D and describe new findings specific to the new reconstruction. Highlights of the new PRISM3D reconstruction include removal of Hudson Bay and the Great Lakes and creation of open waterways in locations where the current bedrock elevation is less than 25m above modern sea level, due to the removal of the West Antarctic Ice Sheet and the reduction of the East Antarctic Ice Sheet. The mid-Piacenzian oceans were characterized by a reduced east-west temperature gradient in the equatorial Pacific, but PRISM3D data do not imply permanent El Niño conditions. The reduced equator-to-pole temperature gradient that characterized previous PRISM reconstructions is supported by significant displacement of vegetation belts toward the poles, is extended into the Arctic Ocean, and is confirmed by multiple proxies in PRISM3D. Arctic warmth coupled with increased dryness suggests the formation of warm and salty paleo North Atlantic Deep Water (NADW) and a more vigorous thermohaline circulation system that may have provided the enhanced ocean heat transport necessary to move warm surface water to the Arctic. New deep ocean temperature data also suggests greater warmth and further southward penetration of paleo NADW.

Dowsett, H.; Robinson, M.; Haywood, A.M.; Salzmann, U.; Hill, Daniel; Sohl, L.E.; Chandler, M.; Williams, Mark; Foley, K.; Stoll, D.K.

2010-01-01

27

Fully 3D GPU PET reconstruction  

Energy Technology Data Exchange (ETDEWEB)

Fully 3D iterative tomographic image reconstruction is computationally very demanding. Graphics Processing Unit (GPU) has been proposed for many years as potential accelerators in complex scientific problems, but it has not been used until the recent advances in the programmability of GPUs that the best available reconstruction codes have started to be implemented to be run on GPUs. This work presents a GPU-based fully 3D PET iterative reconstruction software. This new code may reconstruct sinogram data from several commercially available PET scanners. The most important and time-consuming parts of the code, the forward and backward projection operations, are based on an accurate model of the scanner obtained with the Monte Carlo code PeneloPET and they have been massively parallelized on the GPU. For the PET scanners considered, the GPU-based code is more than 70 times faster than a similar code running on a single core of a fast CPU, obtaining in both cases the same images. The code has been designed to be easily adapted to reconstruct sinograms from any other PET scanner, including scanner prototypes.

Herraiz, J.L., E-mail: joaquin@nuclear.fis.ucm.es [Grupo de Fisica Nuclear, Departmento Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Espana, S. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States); Cal-Gonzalez, J. [Grupo de Fisica Nuclear, Departmento Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Vaquero, J.J. [Departmento de Bioingenieria e Ingenieria Espacial, Universidad Carlos III, Madrid (Spain); Desco, M. [Departmento de Bioingenieria e Ingenieria Espacial, Universidad Carlos III, Madrid (Spain); Unidad de Medicina y Cirugia Experimental, Hospital General Universitario Gregorio Maranon, Madrid (Spain); Udias, J.M. [Grupo de Fisica Nuclear, Departmento Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain)

2011-08-21

28

3D reconstruction from line drawings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work we introduce an approach for reconstructing digital 3D models from multiple perspective line drawings. One major goal is to keep the required user interaction simple and at a minimum, while making no constraints to the objects shape. Such a system provides a useful extension for digitalization of paper-based styling concepts, which today is still a time consuming process. In the presented method the line drawings are first decomposed in curves assembling a network of curves. In a...

2010-01-01

29

Multichannel algorithm for fast 3D reconstruction  

International Nuclear Information System (INIS)

Some recent medical imaging applications such as functional imaging (PET and SPECT) or interventional imaging (CT fluoroscopy) involve increasing amounts of data. In order to reduce the image reconstruction time, we develop a new fast 3D reconstruction algorithm based on a divide and conquer approach. The proposed multichannel algorithm performs an indirect frequential subband decomposition of the image f to be reconstructed (f=?fj) through the filtering of the projections Rf. The subband images fj are reconstructed on a downsampled grid without information suppression. In order to reduce the computation time, we do not backproject the null filtered projections and we downsample the number of projections according to the Shannon conditions associated with the subband image. Our algorithm is based on filtering and backprojection operators. Using the same algorithms for these basic operators, our approach is three and a half times faster than a classical FBP algorithm for a 2D image 512x512 and six times faster for a 3D image 32x512x512. (author)

2002-08-07

30

3D reconstruction of tensors and vectors  

International Nuclear Information System (INIS)

Here we have developed formulations for the reconstruction of 3D tensor fields from planar (Radon) and line-integral (X-ray) projections of 3D vector and tensor fields. Much of the motivation for this work is the potential application of MRI to perform diffusion tensor tomography. The goal is to develop a theory for the reconstruction of both Radon planar and X-ray or line-integral projections because of the flexibility of MRI to obtain both of these type of projections in 3D. The development presented here for the linear tensor tomography problem provides insight into the structure of the nonlinear MRI diffusion tensor inverse problem. A particular application of tensor imaging in MRI is the potential application of cardiac diffusion tensor tomography for determining in vivo cardiac fiber structure. One difficulty in the cardiac application is the motion of the heart. This presents a need for developing future theory for tensor tomography in a motion field. This means developing a better understanding of the MRI signal for diffusion processes in a deforming media. The techniques developed may allow the application of MRI tensor tomography for the study of structure of fiber tracts in the brain, atherosclerotic plaque, and spine in addition to fiber structure in the heart. However, the relations presented are also applicable to other fields in medical imaging such as diffraction tomography using ultrasound. The mathematics presented can also be extended to exponential Radon transform of tensor fields and to other geometric acquisitions such as cone beam tomography of tensor fields

2005-01-01

31

3D reconstruction of tensors and vectors  

Energy Technology Data Exchange (ETDEWEB)

Here we have developed formulations for the reconstruction of 3D tensor fields from planar (Radon) and line-integral (X-ray) projections of 3D vector and tensor fields. Much of the motivation for this work is the potential application of MRI to perform diffusion tensor tomography. The goal is to develop a theory for the reconstruction of both Radon planar and X-ray or line-integral projections because of the flexibility of MRI to obtain both of these type of projections in 3D. The development presented here for the linear tensor tomography problem provides insight into the structure of the nonlinear MRI diffusion tensor inverse problem. A particular application of tensor imaging in MRI is the potential application of cardiac diffusion tensor tomography for determining in vivo cardiac fiber structure. One difficulty in the cardiac application is the motion of the heart. This presents a need for developing future theory for tensor tomography in a motion field. This means developing a better understanding of the MRI signal for diffusion processes in a deforming media. The techniques developed may allow the application of MRI tensor tomography for the study of structure of fiber tracts in the brain, atherosclerotic plaque, and spine in addition to fiber structure in the heart. However, the relations presented are also applicable to other fields in medical imaging such as diffraction tomography using ultrasound. The mathematics presented can also be extended to exponential Radon transform of tensor fields and to other geometric acquisitions such as cone beam tomography of tensor fields.

Defrise, Michel; Gullberg, Grant T.

2005-02-17

32

Penalized Maximum Likelihood Reconstruction for Improved Microcalcification Detection in Breast Tomosynthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We examined the application of an iterative penalized maximum likelihood (PML) reconstruction method for improved detectability of microcalcifications (MCs) in digital breast tomosynthesis (DBT). Localized receiver operating characteristic (LROC) psychophysical studies with human observers and 2D image slices were conducted to evaluate the performance of this reconstruction method and to compare its performance against the commonly used Feldkamp FBP algorithm. DBT projections were generated u...

Das, Mini; Gifford, Howard C.; O Connor, J. Michael; Glick, Stephen J.

2011-01-01

33

Visual road following without 3D reconstruction  

Science.gov (United States)

The traditional approach to visual road following involves reconstructing a 3D model of the road. The model is in a world or vehicle-centered coordinate system, and it is symbolic, iconic, or a combination of both. Road-following commands (as well as other commands, e.g., obstacle avoidance) are then generated from this 3D model. Here we discuss an alternative approach in which a minimal road model is generated. The model contains only task-relevant information and a minimum of vision processing is performed to extract this information in the form of visual cues represented in the 2D image coordinate system. This approach leads to rapid and continuous update of the road model from the visual data. It results in inexpensive, fast, and robust computations. Road following is achieved by servoing on the visual cues in the 2D model. This approach results in a tight coupling of perception and action. In this paper, two specific examples of road following that use this approach are presented. In the first example, we show that road-following commands can be generated from visual cues consisting of the projection into the image of the tangent point on the edge of the road, along with the optical flow of this point. Using this cue, the resulting servo loop is very simple and fast. In the second example, we show that lane markings can be robustly tracked in real time while confining all processing to the 2D image plane. Neither knowledge of vehicle motion nor a calibrated camera is required. This system has been used to drive a vehicle up to 80 km/hr under various road conditions. The algorithm runs at a 15 Hz update rate.

Herman, Martin; Raviv, Daniel; Schneiderman, Henry; Nashman, Marilyn

1994-02-01

34

Background Modeling Method Based on 3D Shape Reconstruction Technology  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this research, we present a novel dynamic background modeling method based on reconstructed 3D shapes, which can solve background modeling problems of multi-camera in real-time. While 3D shape reconstruction is a popular technology widely used for detecting, tracking or identifying various objects, little effort has been made in applying this useful method to background subtraction. In this work we propose an approach to using 3D shape reconstruction technolo...

2013-01-01

35

Assessing the Value of 3D Reconstruction in Building Construction  

CERN Multimedia

3-dimensional (3D) reconstruction is an emerging field in image processing and computer vision that aims to create 3D visualizations/ models of objects/ scenes from image sets. However, its commercial applications and benefits are yet to be fully explored. In this paper, we describe ongoing work towards assessing the value of 3D reconstruction in the building construction domain. We present preliminary results from a user study, where our objective is to understand the use of visual information in building construction in order to determine problems with the use of visual information and identify potential benefits and scenarios for the use of 3D reconstruction.

Murthy, Uma; Dib, Hazar; Garg, Chirag

2012-01-01

36

Pre-computed backprojection based penalized-likelihood (PPL) reconstruction with an edge-preserved regularizer for stationary Digital Breast Tomosynthesis  

Science.gov (United States)

Stationary Digital Breast Tomosynthesis (sDBT) is a carbon nanotube based breast imaging device with fast data acquisition and decent projection resolution to provide three dimensional (3-D) volume information. To- mosynthesis 3-D image reconstruction is faced with the challenges of the cone beam geometry and the incomplete and nonsymmetric sampling due to the sparse views and limited view angle. Among all available reconstruction methods, statistical iterative method exhibits particular promising since it relies on an accurate physical and statistical model with prior knowledge. In this paper, we present the application of an edge-preserved regularizer to our previously proposed precomputed backprojection based penalized-likelihood (PPL) reconstruction. By using the edge-preserved regularizer, our experiments show that through tuning several parameters, resolution can be retained while noise is reduced significantly. Compared to other conventional noise reduction techniques in image reconstruction, less resolution is lost in order to gain certain noise reduction, which may benefit the research of low dose tomosynthesis.

Xu, Shiyu; Inscoe, Christy R.; Lu, Jianping; Zhou, Otto; Chen, Ying

2014-03-01

37

Propose Semantic Formalization for 3D Reconstruction of Architectural  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Archi3D project is a successful practice well proved by engineering practices. In this paper, we propose to reconstruct semantics for the purpose of reconstruct 3D architecture in Archi3D fundamentally. The formalization approach starts from several hypotheses on semantics which include: there is a core mechanism of semantics which is not limited to conceptual expression level; and a complete expression of semantics necessaries the ?implicit?explicit? transition of human side knowledge,...

Cruz, Christophe; Yucong, Duan; Nicolle, Christophe

2010-01-01

38

A structural approach for 3D building reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this report, we present a 3D building reconstruction method based on a structural approach. It consists in reconstructing buildings by assembling simple urban structures extracted from a grammar of 3D parametric models. This method is composed of two stages. The first one, which has already been tackled in previous works, consists in extracting the building footprints through configurations of connected quadrilaterals. The second stage, detailed in this report, corresponds to the 3D recons...

Lafarge, Florent; Descombes, Xavier; Zerubia, Josiane; Pierrot-deseilligny, Marc

2006-01-01

39

Reconstruction and analysis of shapes from 3D scans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis we use 3D laser range scans for the acquisition, reconstruction, and analysis of 3D shapes. 3D laser range scanning has proven to be a fast and effective way to capture the surface of an object in a computer. Thousands of depth measurements represent a part of the surface geometry as a cloud of 3D points and geometric algorithms have been developed to turn such 3D point sets into manageable shapes and shape representations for end users or other algorithms. We use 3D laser rang...

Haar, F. B. Ter

2009-01-01

40

MMSE Reconstruction for 3D Freehand Ultrasound Imaging  

Directory of Open Access Journals (Sweden)

Full Text Available The reconstruction of 3D ultrasound (US images from mechanically registered, but otherwise irregularly positioned, B-scan slices is of great interest in image guided therapy procedures. Conventional 3D ultrasound algorithms have low computational complexity, but the reconstructed volume suffers from severe speckle contamination. Furthermore, the current method cannot reconstruct uniform high-resolution data from several low-resolution B-scans. In this paper, the minimum mean-squared error (MMSE method is applied to 3D ultrasound reconstruction. Data redundancies due to overlapping samples as well as correlation of the target and speckle are naturally accounted for in the MMSE reconstruction algorithm. Thus, the reconstruction process unifies the interpolation and spatial compounding. Simulation results for synthetic US images are presented to demonstrate the excellent reconstruction.

Yibin Zheng

2008-03-01

 
 
 
 
41

Reconstruction of 3D Tooth Images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe a novel approach to obtain a good estimate of the complete 3D representation of a tooth given only the crown. The technique is based on the use of statistical model derived from 3D-images of teeth constructed by microtomography. The root is constructed by matching the respective crowns of the two models, defining the optimal registration, and optimizing the statistical model parameters. This method allows us to generate the root efficiently due to the small number of parameters to...

Buchaillard, Ste?phanie; Ong, Sim Heng; Payan, Yohan; Foong, Kelvin

2004-01-01

42

2D and 3D registration methods for dual-energy contrast-enhanced digital breast tomosynthesis  

Science.gov (United States)

Contrast-enhanced digital breast tomosynthesis (CE-DBT) uses an iodinated contrast agent to image the threedimensional breast vasculature. The University of Pennsylvania is conducting a CE-DBT clinical study in patients with known breast cancers. The breast is compressed continuously and imaged at four time points (1 pre-contrast; 3 postcontrast). A hybrid subtraction scheme is proposed. First, dual-energy (DE) images are obtained by a weighted logarithmic subtraction of the high-energy and low-energy image pairs. Then, post-contrast DE images are subtracted from the pre-contrast DE image. This hybrid temporal subtraction of DE images is performed to analyze iodine uptake, but suffers from motion artifacts. Employing image registration further helps to correct for motion, enhancing the evaluation of vascular kinetics. Registration using ANTS (Advanced Normalization Tools) is performed in an iterative manner. Mutual information optimization first corrects large-scale motions. Normalized cross-correlation optimization then iteratively corrects fine-scale misalignment. Two methods have been evaluated: a 2D method using a slice-by-slice approach, and a 3D method using a volumetric approach to account for out-of-plane breast motion. Our results demonstrate that iterative registration qualitatively improves with each iteration (five iterations total). Motion artifacts near the edge of the breast are corrected effectively and structures within the breast (e.g. blood vessels, surgical clip) are better visualized. Statistical and clinical evaluations of registration accuracy in the CE-DBT images are ongoing.

Lau, Kristen C.; Roth, Susan; Maidment, Andrew D. A.

2014-03-01

43

Weighted simultaneous algebraic reconstruction technique for tomosynthesis imaging of objects with high-attenuation features  

International Nuclear Information System (INIS)

Purpose: This paper introduces a nonlinear weighting scheme into the backprojection operation within the simultaneous algebraic reconstruction technique (SART). It is designed for tomosynthesis imaging of objects with high-attenuation features in order to reduce limited angle artifacts. Methods: The algorithm estimates which projections potentially produce artifacts in a voxel. The contribution of those projections into the updating term is reduced. In order to identify those projections automatically, a four-dimensional backprojected space representation is used. Weighting coefficients are calculated based on a dissimilarity measure, evaluated in this space. For each combination of an angular view direction and a voxel position an individual weighting coefficient for the updating term is calculated. Results: The feasibility of the proposed approach is shown based on reconstructions of the following real three-dimensional tomosynthesis datasets: a mammography quality phantom, an apple with metal needles, a dried finger bone in water, and a human hand. Datasets have been acquired with a Siemens Mammomat Inspiration tomosynthesis device and reconstructed using SART with and without suggested weighting. Out-of-focus artifacts are described using line profiles and measured using standard deviation (STD) in the plane and below the plane which contains artifact-causing features. Artifacts distribution in axial direction is measured using an artifact spread function (ASF). The volumes reconstructed with the weighting scheme demonstrate the reduction of out-of-focus artifacts, lower STD (meaning reduction of artifacts), and narrower ASF compared to nonweighted SART reconstruction. It is achieved successfully for different kinds of structures: point-like structures such as phantom features, long structures such as metal needles, and fine structures such as trabecular bone structures. Conclusions: Results indicate the feasibility of the proposed algorithm to reduce typical tomosynthesis artifacts produced by high-attenuation features. The proposed algorithm assigns weighting coefficients automatically and no segmentation or tissue-classification steps are required. The algorithm can be included into various iterative reconstruction algorithms with an additive updating strategy. It can also be extended to computed tomography case with the complete set of angular data.

2013-03-01

44

Weighted simultaneous algebraic reconstruction technique for tomosynthesis imaging of objects with high-attenuation features  

Energy Technology Data Exchange (ETDEWEB)

Purpose: This paper introduces a nonlinear weighting scheme into the backprojection operation within the simultaneous algebraic reconstruction technique (SART). It is designed for tomosynthesis imaging of objects with high-attenuation features in order to reduce limited angle artifacts. Methods: The algorithm estimates which projections potentially produce artifacts in a voxel. The contribution of those projections into the updating term is reduced. In order to identify those projections automatically, a four-dimensional backprojected space representation is used. Weighting coefficients are calculated based on a dissimilarity measure, evaluated in this space. For each combination of an angular view direction and a voxel position an individual weighting coefficient for the updating term is calculated. Results: The feasibility of the proposed approach is shown based on reconstructions of the following real three-dimensional tomosynthesis datasets: a mammography quality phantom, an apple with metal needles, a dried finger bone in water, and a human hand. Datasets have been acquired with a Siemens Mammomat Inspiration tomosynthesis device and reconstructed using SART with and without suggested weighting. Out-of-focus artifacts are described using line profiles and measured using standard deviation (STD) in the plane and below the plane which contains artifact-causing features. Artifacts distribution in axial direction is measured using an artifact spread function (ASF). The volumes reconstructed with the weighting scheme demonstrate the reduction of out-of-focus artifacts, lower STD (meaning reduction of artifacts), and narrower ASF compared to nonweighted SART reconstruction. It is achieved successfully for different kinds of structures: point-like structures such as phantom features, long structures such as metal needles, and fine structures such as trabecular bone structures. Conclusions: Results indicate the feasibility of the proposed algorithm to reduce typical tomosynthesis artifacts produced by high-attenuation features. The proposed algorithm assigns weighting coefficients automatically and no segmentation or tissue-classification steps are required. The algorithm can be included into various iterative reconstruction algorithms with an additive updating strategy. It can also be extended to computed tomography case with the complete set of angular data.

Levakhina, Y. M. [Institute of Medical Engineering, University of Luebeck, Luebeck 23562, Germany and Graduate School for Computing in Medicine and Life Sciences, Luebeck 23562 (Germany); Mueller, J.; Buzug, T. M. [Institute of Medical Engineering, University of Luebeck, Luebeck 23562 (Germany); Duschka, R. L.; Vogt, F.; Barkhausen, J. [Clinic for Radiology, University Clinics Schleswig-Holstein, Luebeck 23562 (Germany)

2013-03-15

45

Background Modeling Method Based on 3D Shape Reconstruction Technology  

Directory of Open Access Journals (Sweden)

Full Text Available In this research, we present a novel dynamic background modeling method based on reconstructed 3D shapes, which can solve background modeling problems of multi-camera in real-time. While 3D shape reconstruction is a popular technology widely used for detecting, tracking or identifying various objects, little effort has been made in applying this useful method to background subtraction. In this work we propose an approach to using 3D shape reconstruction technology to develop a novel decision making mechanism for background image updating. This 3D shape reconstruction based background subtraction method is adaptive to changes in illumination, capable of handling sudden illumination changes as well as complex dynamic scenes efficiently.

Xue Yuan

2013-04-01

46

3D Medical Volume Reconstruction Using Web Services  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We address the problem of 3D medical volume reconstruction using web services. The use of proposed web services is motivated by the fact that the problem of 3D medical volume reconstruction requires significant computer resources and human expertise in medical and computer science areas. Web services are implemented as an additional layer to a dataflow framework called Data to Knowledge. In the collaboration between UIC and NCSA, pre-processed input images at NCSA are made accessible to medic...

Kooper, Rob; Shirk, Andrew; Lee, Sang-chul; Lin, Amy; Folberg, Robert; Bajcsy, Peter

2008-01-01

47

3D catheter path reconstruction from biplane angiograms  

Science.gov (United States)

The 3D coronary vessels can be reconstructed by means of different cardiac imaging modalities. Two of the most widely used modalities for the purpose of coronary tree reconstruction are intravascular ultrasounds (IVUS) and biplane angiography. Current 3D vessel reconstruction based on IVUS pullback imaging is limited by the lack of information about the real vessel curvature, because the path of the catheter is assumed to be a straight line. This limitation can be overcome if information from an IVUS sequence is fused with a biplane X-ray image of the catheter acquired at the start of the pullback procedure. This work focuses on the reconstruction of the catheter path from biplane angiograms. This reconstruction represents the 3D path followed by the catheter inside the vessel of interest. While other approaches reconstruct the vessel after it has been segmented in both images independently, our approach, based on the snakes technique, allows us to segment and reconstruct the catheter trajectory merging information from both images simultaneously. The result is a more robust reconstruction since 3D constraints can be used and no correspondence of points between the projections is required. This reconstruction will allow a posterior more exact combination of IVUS and biplane angiography image modalities.

Molina, M. C.; Prause, Guido P.; Radeva, Petia; Sonka, Milan

1998-06-01

48

Clinical implementation of a digital tomosynthesis-based seed reconstruction algorithm for intraoperative postimplant dose evaluation in low dose rate prostate brachytherapy  

Energy Technology Data Exchange (ETDEWEB)

Purpose: The low dose rate brachytherapy procedure would benefit from an intraoperative postimplant dosimetry verification technique to identify possible suboptimal dose coverage and suggest a potential reimplantation. The main objective of this project is to develop an efficient, operator-free, intraoperative seed detection technique using the imaging modalities available in a low dose rate brachytherapy treatment room. Methods: This intraoperative detection allows a complete dosimetry calculation that can be performed right after an I-125 prostate seed implantation, while the patient is still under anesthesia. To accomplish this, a digital tomosynthesis-based algorithm was developed. This automatic filtered reconstruction of the 3D volume requires seven projections acquired over a total angle of 60 deg. with an isocentric imaging system. Results: A phantom study was performed to validate the technique that was used in a retrospective clinical study involving 23 patients. In the patient study, the automatic tomosynthesis-based reconstruction yielded seed detection rates of 96.7% and 2.6% false positives. The seed localization error obtained with a phantom study is 0.4{+-}0.4 mm. The average time needed for reconstruction is below 1 min. The reconstruction algorithm also provides the seed orientation with an uncertainty of 10 deg. {+-}8 deg. The seed detection algorithm presented here is reliable and was efficiently used in the clinic. Conclusions: When combined with an appropriate coregistration technique to identify the organs in the seed coordinate system, this algorithm will offer new possibilities for a next generation of clinical brachytherapy systems.

Brunet-Benkhoucha, Malik; Verhaegen, Frank; Lassalle, Stephanie; Beliveau-Nadeau, Dominic; Reniers, Brigitte; Donath, David; Taussky, Daniel; Carrier, Jean-Francois [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada) and CRCHUM, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada)

2009-11-15

49

3D Beam Reconstruction by Fluorescence Imaging  

CERN Document Server

We present a technique for mapping the complete 3D spatial intensity profile of a laser beam from its fluorescence in an atomic vapour. We propagate shaped light through a rubidium vapour cell and record the resonant scattering from the side. From a single measurement we obtain a camera limited resolution of 200 x 200 transverse points and 659 longitudinal points. In constrast to invasive methods in which the camera is placed in the beam path, our method is capable of measuring patterns formed by counterpropagating laser beams. It has high resolution in all 3 dimensions, is fast and can be completely automated. The technique has applications in areas which require complex beam shapes, such as optical tweezers, atom trapping and pattern formation.

Radwell, Neal; Franke-Arnold, Sonja

2013-01-01

50

Characterization of a constrained paired-view technique in iterative reconstruction for breast tomosynthesis  

Energy Technology Data Exchange (ETDEWEB)

Purpose: The order in which the projection views are employed in the reconstruction of tomosynthesis by iterative algorithms, such as simultaneous algebraic reconstruction technique and maximum likelihood, has a strong effect on the rate of convergence, accuracy, and the edge-blurring artifacts in the reconstructed image. The purpose of this investigation was to characterize and evaluate the effects of ordering schemes on image quality for breast tomosynthesis reconstruction and to explore a new constrained paired-view technique that could provide reduction of reconstruction artifacts. In this work, the authors compared several different ordering schemes and characterized the image quality and the formation of out-of-plane artifacts. Furthermore, a new normalization method is presented. It produces more accurate reconstructions with reduced artifacts comparing to the standard method of sequential ordering.Methods: In addition to visual assessment of image quality, several indices such as the signal-difference-to-noise ratio, the artifact-spread function, and the lesion detectability (d{sup ?}) were computed to quantitatively evaluate the effect of ordering scheme. The sets of breast tomosynthesis projection images were simulated for reconstruction; one set had uniform background (white noise only) and the other two contained both anatomic background and quantum noise. Clinical breast images were also studied for comparison.Results: The authors have quantified the image quality in reconstructed slices for a range of tumor sizes. The authors’ proposed method provides better performance for all of the metrics tested (contrast, d{sup ?}, and the level of artifacts) both for the uniform phantom case and in the presence of anatomical structure.Conclusions: The paired projection normalization provides better performance in the image quality of the reconstructed slices, and results in a lower level of artifacts in the Z direction. This implies that even a relatively simple method like the “side-to-side” sequence, which pairs two symmetrical projections with equal angular distance from the central projection, would achieve better reconstructed image quality than the conventional “step-by-step” method, which uses sequential projections one after another.

Wu, Gang; Yaffe, Martin J. [Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada and Sunnybrook Research Institute, S-657, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 Canada (Canada); Mainprize, James G. [Sunnybrook Research Institute, S-657, 2075 Bayview Avenue, Toronto, Ontario M4N 3M5 (Canada)

2013-10-15

51

Comparison of algorithms for out-of-plane artifacts removal in digital tomosynthesis reconstructions.  

Science.gov (United States)

Digital tomosynthesis is a method of limited angle reconstruction of tomographic images produced at variable heights, on the basis of a set of angular projections taken in an arc around human anatomy. Reconstructed tomograms from unprocessed original projection images, however, are invariably affected by tomographic noise such as blurred images of objects lying outside the plane of interest and superimposed on the focused image of the fulcrum plane. The present work investigates the performance of two approaches for generation of tomograms with a reduced noise: a generalised post-processing method, based on constructing a noise mask from all planes in the reconstructed volume, and its subsequent subtraction from the in-focus plane and a filtered Multiple Projection Algorithm. The comparison between the two algorithms shows that the first method provides reconstructions with very good quality in case of high contrast features, especially for those embedded into a heterogeneous background. PMID:22056810

Bliznakova, K; Bliznakov, Z; Buliev, I

2012-07-01

52

PC-based 3D craniofacial reconstruction  

Science.gov (United States)

This article presents a technique, based on PC system, of skull surface triangulation representation for coronal CT images. First, the end-user selects interactively a point within the Region of Interest (ROI), and the computer will automatically position the selected ROI. The boundary points of the ROI is extracted and ordered according to their spatial orientation. Then, the boundary points between two adjacent slices are triangulated by virtual of the optical local morphology. We briefly introduce the technique how to get the patch of skull defect in the commercial software package Surfacer. So the geometric representation using triangular patch can be produced by rapid prototyping and tooling. Finally, the experimental results show that the technique proposed is efficient for the reconstruction of broken part of skull surface and convenient to surgical repair of skull defect. Also, we have found that the technique is robust in implementation.

Zhang, Zonghua; Peng, Xiang; Liu, Changqing; Hu, Xiaotang

2002-09-01

53

NeuralNetwork Based 3D Surface Reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a novel neural-network-based adaptive hybrid-reflectance three-dimensional (3-D) surface reconstruction model. The neural network combines the diffuse and specular components into a hybrid model. The proposed model considers the characteristics of each point and the variant albedo to prevent the reconstructed surface from being distorted. The neural network inputs are the pixel values of the two-dimensional images to be reconstructed. The normal vectors o...

Joseph, Vincy; Bhatia, Shalini

2009-01-01

54

Usefulness of reconstructed 3D-CT for magerl technique  

International Nuclear Information System (INIS)

It is obviously important to determine safe screwing in transarticular atlanto-axial fixation by the Magerl technique by evaluating the morphological features of the screw passing route. In the present study, we investigated the availability of reconstructed 3D-CT to prevent vertebral artery injury in this technique. Thirty patients underwent reconstructed 3D-CT prior to the operation to determine whether safe screw fixation by the Magerl technique, imaging coronal, and sagittal reconstruction CT were possible. As a result, safe screwing was found to be impossible in four cases, of which two therefore underwent Brooks's method and the other two cases O-C2 fusion. Twenty-six cases who were compatible with Magerl's method had no neuro-vascular complications. We concluded that reconstructed 3D-CT is useful for determining safe screw fixation by the Magerl technique. (author)

2005-03-01

55

3D Image Reconstruction: Determination of Pattern Orientation  

Energy Technology Data Exchange (ETDEWEB)

The problem of determining the euler angles of a randomly oriented 3-D object from its 2-D Fraunhofer diffraction patterns is discussed. This problem arises in the reconstruction of a positive semi-definite 3-D object using oversampling techniques. In such a problem, the data consists of a measured set of magnitudes from 2-D tomographic images of the object at several unknown orientations. After the orientation angles are determined, the object itself can then be reconstructed by a variety of methods using oversampling, the magnitude data from the 2-D images, physical constraints on the image and then iteration to determine the phases.

Blankenbecler, Richard

2003-03-13

56

3D reconstruction based on spatial vanishing information  

Science.gov (United States)

An approach for the three-dimensional (3D) reconstruction of architectural scenes from two un-calibrated images is described in this paper. From two views of one architectural structure, three pairs of corresponding vanishing points of three major mutual orthogonal directions can be extracted. The simple but powerful constraints of parallelism and orthogonal lines in architectural scenes can be used to calibrate the cameras and to recover the 3D information of the structure. This approach is applied to the real images of architectural scenes, and a 3D model of a building in virtual reality modelling language (VRML) format is presented which illustrates the method with successful performance.

Shu, Yuan; Tan, Zheng

2005-03-01

57

Convex Optimization Methods for Single View 3D Reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Reconstructing the 3D geometry from a single image is a strongly ill-posed problem and unique depth values can only be inferred in very specific cases. In this thesis several variational methods are proposed that are based on the principle of minimal surfaces and are solved with methods from convex optimization. Additional constraints such as fixed surface volume, shape or volume ratios are introduced that lead to good reconstructions from a wide class of natural and man-made objects.

2014-01-01

58

Computerized 3-D reconstruction of two "double teeth"  

Digital Repository Infrastructure Vision for European Research (DRIVER)

"Double teeth" is a root malformation in the dentition and the purpose of this study was to reconstruct three-dimensionally the external and internal morphology of two "double teeth". The first set of "double teeth" was formed by the conjunction of a mandibular molar and a premolar, and the second by a conjunction of a maxillary molar and a supernumerary tooth. The process of 3-D reconstruction included serial cross-sectioning, photographs of the sections, digitization of the photographs, ext...

Lyroudia, K.; Mikrogeorgis, G.; Nikopoulos, N.; Samakovitis, G.; Molyvdas, I.; Pitas, I.

2010-01-01

59

Software for 3D diagnostic image reconstruction and analysis  

International Nuclear Information System (INIS)

Recent advances in computer technologies have opened new frontiers in medical diagnostics. Interesting possibilities are the use of three-dimensional (3D) imaging and the combination of images from different modalities. Software prepared in our laboratories devoted to 3D image reconstruction and analysis from computed tomography and ultrasonography is presented. In developing our software it was assumed that it should be applicable in standard medical practice, i.e. it should work effectively with a PC. An additional feature is the possibility of combining 3D images from different modalities. The reconstruction and data processing can be conducted using a standard PC, so low investment costs result in the introduction of advanced and useful diagnostic possibilities. The program was tested on a PC using DICOM data from computed tomography and TIFF files obtained from a 3D ultrasound system. The results of the anthropomorphic phantom and patient data were taken into consideration. A new approach was used to achieve spatial correlation of two independently obtained 3D images. The method relies on the use of four pairs of markers within the regions under consideration. The user selects the markers manually and the computer calculates the transformations necessary for coupling the images. The main software feature is the possibility of 3D image reconstruction from a series of two-dimensional (2D) images. The reconstructed 3D image can be: (1) viewed with the most popular methods of 3D image viewing, (2) filtered and processed to improve image quality, (3) analyzed quantitatively (geometrical measurements), and (4) coupled with another, independently acquired 3D image. The reconstructed and processed 3D image can be stored at every stage of image processing. The overall software performance was good considering the relatively low costs of the hardware used and the huge data sets processed. The program can be freely used and tested (source code and program available at http://www.biofizyka.cm-uj.krakow.pl). Improvements allowing the processing of new data types and new procedures can be implemented for specific demands. (author)

2005-01-01

60

3D volumetric analysis for planning breast reconstructive surgery.  

Science.gov (United States)

Breast reconstruction plays an integral role in the holistic management of breast cancer, with assessment of breast volume, shape, and projection vital in planning breast reconstruction surgery. Current practice includes two-dimensional (2D) photography and visual estimation in selecting ideal volume and shape of breast implants or soft-tissue flaps. Other objective quantitative means of calculating breast volume have been reported, such as direct anthropomorphic measurements or three-dimensional (3D) photography, but none have proven reliably accurate. We describe a novel approach to volumetric analysis of the breast, through the creation of a haptic, tactile model, or 3D print of scan data. This approach comprises use of a single computed tomography (CT) or magnetic resonance imaging (MRI) scan for volumetric analysis, which we use to compare to simpler estimation techniques, create software-generated 3D reconstructions, calculate, and visualize volume differences, and produce biomodels of the breasts using a 3D printer for tactile appreciation of volume differential. Using the technique described, parenchymal volume was assessed and calculated using CT data. A case report was utilized in a pictorial account of the technique, in which a volume difference of 116 cm(3) was calculated, aiding reconstructive planning. Preoperative planning, including volumetric analysis can be used as a tool to aid esthetic outcomes and attempt to reduce operative times in post-mastectomy breast reconstruction surgery. The combination of accurate volume calculations and the production of 3D-printed haptic models for tactile feedback and operative guidance are evolving techniques in volumetric analysis and preoperative planning in breast reconstruction. PMID:24939062

Chae, Michael P; Hunter-Smith, David J; Spychal, Robert T; Rozen, Warren Matthew

2014-07-01

 
 
 
 
61

3D medical volume reconstruction using web services.  

Science.gov (United States)

We address the problem of 3D medical volume reconstruction using web services. The use of proposed web services is motivated by the fact that the problem of 3D medical volume reconstruction requires significant computer resources and human expertise in medical and computer science areas. Web services are implemented as an additional layer to a dataflow framework called data to knowledge. In the collaboration between UIC and NCSA, pre-processed input images at NCSA are made accessible to medical collaborators for registration. Every time UIC medical collaborators inspected images and selected corresponding features for registration, the web service at NCSA is contacted and the registration processing query is executed using the image to knowledge library of registration methods. Co-registered frames are returned for verification by medical collaborators in a new window. In this paper, we present 3D volume reconstruction problem requirements and the architecture of the developed prototype system at http://isda.ncsa.uiuc.edu/MedVolume. We also explain the tradeoffs of our system design and provide experimental data to support our system implementation. The prototype system has been used for multiple 3D volume reconstructions of blood vessels and vasculogenic mimicry patterns in histological sections of uveal melanoma studied by fluorescent confocal laser scanning microscope. PMID:18336808

Kooper, Rob; Shirk, Andrew; Lee, Sang-Chul; Lin, Amy; Folberg, Robert; Bajcsy, Peter

2008-04-01

62

Evaluation of digital breast tomosynthesis reconstruction algorithms using synchrotron radiation in standard geometry  

Energy Technology Data Exchange (ETDEWEB)

Purpose: In this article, the image quality of reconstructed volumes by four algorithms for digital tomosynthesis, applied in the case of breast, is investigated using synchrotron radiation. Methods: An angular data set of 21 images of a complex phantom with heterogeneous tissue-mimicking background was obtained using the SYRMEP beamline at ELETTRA Synchrotron Light Laboratory, Trieste, Italy. The irradiated part was reconstructed using the multiple projection algorithm (MPA) and the filtered backprojection with ramp followed by hamming windows (FBR-RH) and filtered backprojection with ramp (FBP-R). Additionally, an algorithm for reducing the noise in reconstructed planes based on noise mask subtraction from the planes of the originally reconstructed volume using MPA (MPA-NM) has been further developed. The reconstruction techniques were evaluated in terms of calculations and comparison of the contrast-to-noise ratio (CNR) and artifact spread function. Results: It was found that the MPA-NM resulted in higher CNR, comparable with the CNR of FBP-RH for high contrast details. Low contrast objects are well visualized and characterized by high CNR using the simple MPA and the MPA-NM. In addition, the image quality of the reconstructed features in terms of CNR and visual appearance as a function of the initial number of projection images and the reconstruction arc was carried out. Slices reconstructed with more input projection images result in less reconstruction artifacts and higher detail CNR, while those reconstructed from projection images acquired in reduced angular range causes pronounced streak artifacts. Conclusions: Of the reconstruction algorithms implemented, the MPA-NM and MPA are a good choice for detecting low contrast objects, while the FBP-RH, FBP-R, and MPA-NM provide high CNR and well outlined edges in case of microcalcifications.

Bliznakova, K.; Kolitsi, Z.; Speller, R. D.; Horrocks, J. A.; Tromba, G.; Pallikarakis, N. [Department of Medical Physics, School of Medicine, University of Patras, Rio, Patras GR-26500 (Greece); Department of Medical Physics and Bioengineering, University College London, London WC1E 6BT (United Kingdom); Clinical Physics Group, St. Bartholomew' s Hospital, Barts and the London NHS Trust, London EC1A 7BE (United Kingdom); ELETTRA, Basovizza, Trieste I-34012 (Italy); Department of Medical Physics, School of Medicine, University of Patras, Rio, Patras GR-26500 (Greece)

2010-04-15

63

Evaluation of digital breast tomosynthesis reconstruction algorithms using synchrotron radiation in standard geometry  

International Nuclear Information System (INIS)

Purpose: In this article, the image quality of reconstructed volumes by four algorithms for digital tomosynthesis, applied in the case of breast, is investigated using synchrotron radiation. Methods: An angular data set of 21 images of a complex phantom with heterogeneous tissue-mimicking background was obtained using the SYRMEP beamline at ELETTRA Synchrotron Light Laboratory, Trieste, Italy. The irradiated part was reconstructed using the multiple projection algorithm (MPA) and the filtered backprojection with ramp followed by hamming windows (FBR-RH) and filtered backprojection with ramp (FBP-R). Additionally, an algorithm for reducing the noise in reconstructed planes based on noise mask subtraction from the planes of the originally reconstructed volume using MPA (MPA-NM) has been further developed. The reconstruction techniques were evaluated in terms of calculations and comparison of the contrast-to-noise ratio (CNR) and artifact spread function. Results: It was found that the MPA-NM resulted in higher CNR, comparable with the CNR of FBP-RH for high contrast details. Low contrast objects are well visualized and characterized by high CNR using the simple MPA and the MPA-NM. In addition, the image quality of the reconstructed features in terms of CNR and visual appearance as a function of the initial number of projection images and the reconstruction arc was carried out. Slices reconstructed with more input projection images result in less reconstruction artifacts and higher detail CNR, while those reconstructed from projection images acquired in reduced angular range causes pronounced streak artifacts. Conclusions: Of the reconstruction algorithms implemented, the MPA-NM and MPA are a good choice for detecting low contrast objects, while the FBP-RH, FBP-R, and MPA-NM provide high CNR and well outlined edges in case of microcalcifications.

2010-04-01

64

QUANTITATIVE 3D RECONSTRUCTIONS AS IDENTIFICATION TOOL IN HEART DEVELOPMENT  

Directory of Open Access Journals (Sweden)

Full Text Available A method for displaying quantitative information in 3D reconstructions of the embryonic heart was developed to investigate spatial distributions of cell division and cell density. The method utilizes serial sections to extract morphological as well as quantitative data. The morphological data are used to reconstruct the embryonic heart and the quantitative data are classified and superimposed on the resulting reconstruction. The bias, which would result from size differences between cell populations, was investigated. If present, it would influence the absolute number of particles (nuclei per volume, although the classification applied on the reconstruction displaying the mitotic fraction remains unchanged. Although the reconstruction displaying the local densities is influenced by the bias, less than 2.5% of the regions is misclassified.

Alexandre T Soufan

2011-05-01

65

A comparison of reconstruction algorithms for C-arm mammography tomosynthesis  

International Nuclear Information System (INIS)

Digital tomosynthesis is an imaging technique to produce a tomographic image from a series of angular digital images in a manner similar to conventional focal plane tomography. Unlike film focal plane tomography, the acquisition of the data in a C-arm geometry causes the image receptor to be positioned at various angles to the reconstruction tomogram. The digital nature of the data allows for input images to be combined into the desired plane with the flexibility of generating tomograms of many separate planes from a single set of input data. Angular datasets were obtained of a low contrast detectability (LCD) phantom and cadaver breast utilizing a Lorad stereotactic biopsy unit with a coupled source and digital detector in a C-arm configuration. Datasets of 9 and 41 low-dose projections were collected over a 30 deg. angular range. Tomographic images were reconstructed using a Backprojection (BP) algorithm, an Iterative Subtraction (IS) algorithm that allows the partial subtraction of out-of-focus planes, and an Algebraic Reconstruction (AR) algorithm. These were compared with single view digital radiographs. The methods' effectiveness at enhancing visibility of an obscured LCD phantom was quantified in terms of the Signal to Noise Ratio (SNR), and Signal to Background Ratio (SBR), all normalized to the metric value for the single projection image. The methods' effectiveness at removing ghosting artifacts in a cadaver breast was quantified in terms of the Artifact Spread Function (ASF). The technology proved effective at partially removing out of focus structures and enhancing SNR and SBR. The normalized SNR was highest at 4.85 for the obscured LCD phantom, using nine projections and IS algorithm. The normalized SBR was highest at 23.2 for the obscured LCD phantom, using 41 projections and an AR algorithm. The highest normalized metric values occurred with the obscured phantom. This supports the assertion that the greatest value of tomosynthesis is in imaging fibroglandular breasts. The ASF performance was best with the AR technique and nine projections

2006-08-01

66

Reconstruction of 3D object's surface image using linear beam  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This dissertation investigates issues relevant to virtualization of a real 3D object – that is, producing a model of the object from its image data, and then visualizing this model as an image seen on the computer screen The object of investigation is methods and algorythms for reconstruction of a complex geometric shape from a number of unorganised point sets in to electronic form. Unorganised point sets are obtained by scanning the 3d object from defferent points of view. The choise of th...

Matiukas, Vilius

2012-01-01

67

VISIRE. Photorealistic 3D Reconstruction from Video Sequences  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Traditionally, building 3D reconstructions of large scenarios such as a museum or historical site has been costly, time consuming and required the contribution of expert personnel. Usually the results showed an artificial look and had little interactivity. However, newly developed technologies in the areas of video analysis, camera calibration and texture fusion allow us to think in a much more satisfying scenario where the user with the only aid of a domestic video camera is able to acquire ...

Rodriguez, Tomas; Sturm, Peter; Wilczkowiak, Marta; Bartoli, Adrien; Peronnaz, Mathieu; Guilbert, Nicolas; Kahl, Fredrik; Johansson, Martin; Heyden, Anders; Mene?ndez, Jose?; Ronda, Jose?; Jaureguizar, Fernando

2003-01-01

68

Visual fidelity of 3D regular sampling and reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

For generic 3D sampling, the Body Centered Cubic (BCC) lattice and the Face Centered Cubic (FCC) lattice are significantly superior to the traditionally popular Cartesian Cubic (CC) lattice. Motivated by the goal of high visual fidelity in the visualization community, this thesis investigates the relative perceptual merits of high quality reconstruction filters for CC, BCC, and FCC sampled data. We recruited 24 participants and gave them pairs of images to discriminate. For each pair, a parti...

2007-01-01

69

High Resolution 3d Reconstructions of Rocks and Composites Reconstructions 3D haute résolution de roches et de composites  

Directory of Open Access Journals (Sweden)

Full Text Available Ten micrometers resolution 3D representations of different media, were obtained with a laboratory computer microtomograph developed from an electron microprobe column. From the original electron microprobe, only minor modifications have been required, indeed several of the utilities of the microprobe have been used to ensure high resolution radiography (2 micrometers. The impact of the electron beam focused onto a thin film is used to form a pointX-ray source and the radiographic image of the sample is acquired on a CCD camera. A specimen rotation mechanism allows multiple radiograph acquisition and reconstruction of the X-ray attenuation 3D cartography. Since X-ray attenuation is directly related to density and atomic number, the microscanner provides 3D cartographs of the different phases present in the sample. System performances have been evaluated on various samples, mainly rocks and composites. Comparison with scanning electron micrographs was used when possible to validate the reconstructions. Results are mostly qualitative but already show the potential of the technique in describing 3D connectivity and topology of pore networks or 3D orientation of fibres in composites. Des représentations tridimensionnelles de différents milieux ont été obtenues avec une résolution de 10 micromètres en utilisant un microscanner développé au laboratoire à partir d'une microsonde électronique. Peu de modifications ont été nécessaires. Certains éléments de la microsonde ont même été conservés pour assurer la stabilité de l'acquisition et permettre l'obtention de radiographies haute résolution (2 micromètres. L'impact d'un faisceau d'électrons focalisé sur un film mince constitue la source X et l'image radiographiée de l'échantillon est acquise à l'aide d'une caméra CCD. Un mécanisme de rotation de l'échantillon permet l'acquisition de radiographies à différentes positions angulaires ainsi que la reconstruction de la cartographie 3D des coefficients d'atténuation. L'atténuation des rayons X étant directement reliée à la densité et au numéro atomique du matériau irradié, le microscanner fournit une cartographie 3D des différentes phases présentes dans l'échantillon. Les performances du système ont été testées sur divers échantillons, principalement des roches et des matériaux composites. La comparaison avec des images de microscopie électronique à balayage a été utilisée pour valider les reconstructions. Les résultats sont pour la plupart qualitatifs mais montrent déjà le potentiel de cette technique pour décrire la topologie et la connectivité 3D de milieux poreux ou l'orientation des fibres dans des composites renforcés de fibres de verre.

Rosenberg E.

2006-12-01

70

Projective 3D-reconstruction of Uncalibrated Endoscopic Images  

Directory of Open Access Journals (Sweden)

Full Text Available The most common medical diagnostic method for urinary bladder cancer is cystoscopy. This inspection of the bladder is performed by a rigid endoscope, which is usually guided close to the bladder wall. This causes a very limited field of view; difficulty of navigation is aggravated by the usage of angled endoscopes. These factors cause difficulties in orientation and visual control. To overcome this problem, the paper presents a method for extracting 3D information from uncalibrated endoscopic image sequences and for reconstructing the scene content. The method uses the SURF-algorithm to extract features from the images and relates the images by advanced matching. To stabilize the matching, the epipolar geometry is extracted for each image pair using a modified RANSAC-algorithm. Afterwards these matched point pairs are used to generate point triplets over three images and to describe the trifocal geometry. The 3D scene points are determined by applying triangulation to the matched image points. Thus, these points are used to generate a projective 3D reconstruction of the scene, and provide the first step for further metric reconstructions.

P. Faltin

2010-01-01

71

High Precision Texture Reconstruction for 3d Sculpture Model  

Science.gov (United States)

High precision 3D sculpture model can take the accurate records of the shape, material and color on the surface of the sculpture. It is an important foundation work of digital documentation, preservation, archaeological research and analysis for the sculpture types of cultural heritage. Constructing high precision 3D sculpture model includes two aspects: geometry modeling and texture reconstruction. But, there are many urgent problems still existing in the method of high precision texture reconstruction. This paper discussed a method of high precision texture reconstruction based on non-rigid transformation for 3D sculpture model. First, coarse registration of texture image to geometrical model is conducted with direct linear transformation (DLT) method. Then, the registration is optimized with thin plane spline (TPS) function to reduce local matching errors between texture image and geometrical model. Finally, texture mapping is implemented with optimized registration result. The experiments based on the sculpture in Dunhuang Mogao Grottoes of China are conducted, and the efficiency and feasibility of the proposed methods are proved.

Zhang, F.; Huang, H.; Zhang, Z.; Fang, W.; Li, D.

2012-07-01

72

Complete 3D surface reconstruction from unstructured point cloud  

International Nuclear Information System (INIS)

In this study, a complete 3D surface reconstruction method is proposed based on the concept that the vertices of surface model can be completely matched to the unstructured point cloud. In order to generate the initial mesh model from the point cloud, the mesh subdivision of bounding box and shrink-wrapping algorithm are introduced. The control mesh model for well representing the topology of point cloud is derived from the initial mesh model by using the mesh simplification technique based on the original QEM algorithm, and the parametric surface model for approximately representing the geometry of point cloud is derived by applying the local subdivision surface fitting scheme on the control mesh model. And, to reconstruct the complete matching surface model, the insertion of isolated points on the parametric surface model and the mesh optimization are carried out. Especially, the fast 3D surface reconstruction is realized by introducing the voxel-based nearest-point search algorithm, and the simulation results reveal the availability of the proposed surface reconstruction method

2005-04-01

73

A new algorithm for 3D reconstruction from support functions  

DEFF Research Database (Denmark)

We introduce a new algorithm for reconstructing an unknown shape from a finite number of noisy measurements of its support function. The algorithm, based on a least squares procedure, is very easy to program in standard software such as Matlab and allows, for the first time, good 3D reconstructions to be performed on an ordinary PC. Under mild conditions, theory guarantees that outputs of the algorithm will converge to the input shape as the number of measurements increases. Reconstructions may be obtained without any pre- or post-processing steps and with no restriction on the sets of measurement directions except their number, a limitation dictated only by computing time. In addition we offer a linear program version of the new algorithm that is much faster and better, or at least comparable, in performance at low levels of noise and reasonably small numbers of measurements. Another modification of the algorithm, suitable for use in a ``focus of attention'' scheme, is also described.

Gardner, Richard; Kiderlen, Markus

2009-01-01

74

Reconstruction of 3-D histology images by simultaneous deformable registration.  

Science.gov (United States)

The reconstruction of histology sections into a 3-D volume receives increased attention due to its various applications in modern medical image analysis. To guarantee a geometrically coherent reconstruction, we propose a new way to register histological sections simuItaneously to previously acquired reference images and to neighboring slices in the stack. To this end, we formulate two potential functions and associate them to the same Markov random field through which we can efficiently find an optimal solution. Due to our simultaneous formulation and the absence of any segmentation step during the reconstruction we can dramatically reduce error propagation effects. This is illustrated by experiments on carefully created synthetic as well as real data sets. PMID:21995076

Feuerstein, Marco; Heibel, Hauke; Gardiazabal, José; Navab, Nassir; Groher, Martin

2011-01-01

75

Enhanced imaging of microcalcifications in digital breast tomosynthesis through improved image-reconstruction algorithms  

International Nuclear Information System (INIS)

Purpose: The authors develop a practical, iterative algorithm for image-reconstruction in undersampled tomographic systems, such as digital breast tomosynthesis (DBT). Methods: The algorithm controls image regularity by minimizing the image total p variation (TpV), a function that reduces to the total variation when p=1.0 or the image roughness when p=2.0. Constraints on the image, such as image positivity and estimated projection-data tolerance, are enforced by projection onto convex sets. The fact that the tomographic system is undersampled translates to the mathematical property that many widely varied resultant volumes may correspond to a given data tolerance. Thus the application of image regularity serves two purposes: (1) Reduction in the number of resultant volumes out of those allowed by fixing the data tolerance, finding the minimum image TpV for fixed data tolerance, and (2) traditional regularization, sacrificing data fidelity for higher image regularity. The present algorithm allows for this dual role of image regularity in undersampled tomography. Results: The proposed image-reconstruction algorithm is applied to three clinical DBT data sets. The DBT cases include one with microcalcifications and two with masses. Conclusions: Results indicate that there may be a substantial advantage in using the present image-reconstruction algorithm for microcalcification imaging.

2009-11-01

76

Three-dimensional linear system analysis for breast tomosynthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The optimization of digital breast tomosynthesis (DBT) geometry and reconstruction is crucial for the clinical translation of this exciting new imaging technique. In the present work, the authors developed a three-dimensional (3D) cascaded linear system model for DBT to investigate the effects of detector performance, imaging geometry, and image reconstruction algorithm on the reconstructed image quality. The characteristics of a prototype DBT system equipped with an amorphous selenium flat-p...

Zhao, Bo; Zhao, Wei

2008-01-01

77

Fast implementations of reconstruction-based scatter compensation in fully 3D SPECT image reconstruction  

International Nuclear Information System (INIS)

Accurate scatter compensation in SPECT can be performed by modelling the scatter response function during the reconstruction process. This method is called reconstruction-based scatter compensation (RBSC). It has been shown that RBSC has a number of advantages over other methods of compensating for scatter, but using RBSC for fully 3D compensation has resulted in prohibitively long reconstruction times. In this work we propose two new methods that can be used in conjunction with existing methods to achieve marked reductions in RBSC reconstruction times. The first method, coarse-grid scatter modelling, significantly accelerates the scatter model by exploiting the fact that scatter is dominated by low-frequency information. The second method, intermittent RBSC, further accelerates the reconstruction process by limiting the number of iterations during which scatter is modelled. The fast implementations were evaluated using a Monte Carlo simulated experiment of the 3D MCAT phantom with 99mTc tracer, and also using experimentally acquired data with 201Tl tracer. Results indicated that these fast methods can reconstruct, with fully 3D compensation, images very similar to those obtained using standard RBSC methods, and in reconstruction times that are an order of magnitude shorter. Using these methods, fully 3D iterative reconstruction with RBSC can be performed well within the realm of clinically realistic times (under 10 minutes for 64x64x24 image reconstruction). (author)

1998-04-01

78

A 3-D industrial CT reconstruction algorithm to directly reconstruct the characteristics  

Energy Technology Data Exchange (ETDEWEB)

In traditional 3-D CT reconstruction methods, for the projection procedure is low-pass smoothing, the high-frequency characters are difficult to obtain after the projection data are reconstructed. In addition the design and implementation of three-dimensional filter are relatively harder. A new 3D industrial CT reconstruction algorithm to directly reconstruct the characteristics is put forth. Based on the FDK method and the trait of RADON transform, the feasibility of the novel algorithm is theoretically deduced. Combined with the wavelet, it is deduced to extract the characteristics using the 2-D wavelet transform and to directly reconstruct the characteristics in 3-D CT. The experiments show that the algorithm can preferably stand out the useful information, is of engineering practicability and the design of the filter is relatively simpler.

Zhao Yingliang, E-mail: zhaoyl18@163.co [National Key Laboratory for Electronic Measurement Technology, North University of China, Tai Yuan 030051 (China); Wang Liming; Han Yan [National Key Laboratory for Electronic Measurement Technology, North University of China, Tai Yuan 030051 (China)

2011-01-21

79

Digital tomosynthesis: technique.  

Science.gov (United States)

Digital breast tomosynthesis is an extension of digital mammography that produces quasi three-dimensional reconstructed images from a set of low-dose x-ray projections acquired over a limited angular range. The quality of the reconstructed image and the dose to the breast are dependent on the angular range and number of projections, the dose used per projection, and detector resolution and noise characteristics. This article discusses various aspects of tomosynthesis optimization. PMID:24792651

Yaffe, Martin J; Mainprize, James G

2014-05-01

80

Toward a dose reduction strategy using model-based reconstruction with limited-angle tomosynthesis  

Science.gov (United States)

Model-based iterative reconstruction (MBIR) is an emerging technique for several imaging modalities and appli- cations including medical CT, security CT, PET, and microscopy. Its success derives from an ability to preserve image resolution and perceived diagnostic quality under impressively reduced signal level. MBIR typically uses a cost optimization framework that models system geometry, photon statistics, and prior knowledge of the recon- structed volume. The challenge of tomosynthetic geometries is that the inverse problem becomes more ill-posed due to the limited angles, meaning the volumetric image solution is not uniquely determined by the incom- pletely sampled projection data. Furthermore, low signal level conditions introduce additional challenges due to noise. A fundamental strength of MBIR for limited-views and limited-angle is that it provides a framework for constraining the solution consistent with prior knowledge of expected image characteristics. In this study, we analyze through simulation the capability of MBIR with respect to prior modeling components for limited-views, limited-angle digital breast tomosynthesis (DBT) under low dose conditions. A comparison to ground truth phantoms shows that MBIR with regularization achieves a higher level of fidelity and lower level of blurring and streaking artifacts compared to other state of the art iterative reconstructions, especially for high contrast objects. The benefit of contrast preservation along with less artifacts may lead to detectability improvement of microcalcification for more accurate cancer diagnosis.

Haneda, Eri; Tkaczyk, J. E.; Palma, Giovanni; Iordache, R?zvan; Zelakiewicz, Scott; Muller, Serge; De Man, Bruno

2014-03-01

 
 
 
 
81

Statistical iterative reconstruction using fast optimization transfer algorithm with successively increasing factor in Digital Breast Tomosynthesis  

Science.gov (United States)

Statistical iterative reconstruction exhibits particularly promising since it provides the flexibility of accurate physical noise modeling and geometric system description in transmission tomography system. However, to solve the objective function is computationally intensive compared to analytical reconstruction methods due to multiple iterations needed for convergence and each iteration involving forward/back-projections by using a complex geometric system model. Optimization transfer (OT) is a general algorithm converting a high dimensional optimization to a parallel 1-D update. OT-based algorithm provides a monotonic convergence and a parallel computing framework but slower convergence rate especially around the global optimal. Based on an indirect estimation on the spectrum of the OT convergence rate matrix, we proposed a successively increasing factor- scaled optimization transfer (OT) algorithm to seek an optimal step size for a faster rate. Compared to a representative OT based method such as separable parabolic surrogate with pre-computed curvature (PC-SPS), our algorithm provides comparable image quality (IQ) with fewer iterations. Each iteration retains a similar computational cost to PC-SPS. The initial experiment with a simulated Digital Breast Tomosynthesis (DBT) system shows that a total 40% computing time is saved by the proposed algorithm. In general, the successively increasing factor-scaled OT exhibits a tremendous potential to be a iterative method with a parallel computation, a monotonic and global convergence with fast rate.

Xu, Shiyu; Zhang, Zhenxi; Chen, Ying

2014-03-01

82

3D airway tree reconstruction in healthy subjects and emphysema.  

Science.gov (United States)

Several algorithms for the segmentation of the 3D human airway tree from computed tomography (CT) images have recently been proposed, but the effects of lung volume and the presence of emphysema on segmentation accuracy has not been investigated. Two different sets of CT images taken on nine healthy subjects and nine patients with severe emphysema (FEV(1) = 19 ± 4.1 SD % pred) were used to reconstruct the trachea-bronchial tree by a region-growing algorithm at two different lung volumes: total lung capacity (TLC) and residual volume (RV). The sixth generation was reached in 67% of the healthy subjects and 22% of the emphysematous patients at TLC. At RV, fifth generation was reached in 33 and 11% of healthy subjects and emphysematous patients. At TLC, 67 ± 2 and 39 ± 2% of airways belonging to the fourth generation were successfully reconstructed, respectively in healthy and emphysematous subjects. At RV, the percentage of successful reconstruction was 33 ± 2 and 16 ± 2%, respectively. Segmentation was significantly influenced by the presence of disease (P < 0.001) and lung volume (P < 0.001) at which the CT scans were acquired. Airway tree reconstruction performed by means of a region-growing algorithm depends on lung volume and presence of emphysema, both of which have significant effect, even at the level of lobar and segmental bronchi. PMID:21688115

Salito, Caterina; Barazzetti, Livia; Woods, Jason C; Aliverti, Andrea

2011-08-01

83

Strategy for 3D Reconstruction of Industrial Rubber Part  

Directory of Open Access Journals (Sweden)

Full Text Available

The motivation for this paper comes from problems involved with the 3D surface reconstruction of the black components in rubber industry. In this paper, a stereo vision system made by two low-cost cameras, a multi-media projector is explained at first. In order to calibrate cameras, an algorithm based on quaternion attitude description is applied to simplify initial values achieving procedure and overcome the correlation problems of the least square estimation based on 2D planar pattern. A method combined with gray code and epipolar geometry is adopted to deal with the matching problem without texture. The whole mathematical algorithms for 3D space coordinates are proposed based on the linear computation and nonlinear space intersection from stereo vision. The experimental results shows that the relative accuracy for 3D reconstruction could reach 1/10000. This indicated that the methods used in this paper were feasible for 3D reconstruction of textureless objects.

Hongxia Cui

2012-02-01

84

Simultaneous 3-D human-motion tracking and voxel reconstruction  

Science.gov (United States)

Under the assumption that no dynamic prior is given, the main obstacle to practical human-motion tracking is the high number of dimensions associated with a 3-D articulated full-body model. We present a method for 3-D human-motion tracking when the training data are unavailable in advance and no motion pattern prior is assumed. Based on the framework of the annealed particle filter, the proposed algorithm incrementally learns the eigenspace as a compact representation of motion patterns and efficiently adapts to pose changes. The model updates using the principal-component analysis, and introduces a forgetting factor to avoid overfitting. In addition, the likelihood measure is modeled by minimizing a cost function on the 3-D Markov random field (MRF), which integrates the information from visual hull and shape priors. A dynamic graph cut is performed to speed up the minimization process. As a result, the proposed approach is capable of obtaining the pose in parallel with the voxel data. Experimental results suggest that our method performs online tracking robustly and generates reconstructions beyond the shape from silhouette method from sparse camera views.

Yan, Junchi; Song, Jian; Liu, Yuncai

2010-09-01

85

3D Reconstruction of Irregular Buildings and Buddha Statues  

Science.gov (United States)

Three-dimensional laser scanning could acquire object's surface data quickly and accurately. However, the post-processing of point cloud is not perfect and could be improved. Based on the study of 3D laser scanning technology, this paper describes the details of solutions to modelling irregular ancient buildings and Buddha statues in Jinshan Temple, which aiming at data acquisition, modelling and texture mapping, etc. In order to modelling irregular ancient buildings effectively, the structure of each building is extracted manually by point cloud and the textures are mapped by the software of 3ds Max. The methods clearly combine 3D laser scanning technology with traditional modelling methods, and greatly improves the efficiency and accuracy of the ancient buildings restored. On the other hand, the main idea of modelling statues is regarded as modelling objects in reverse engineering. The digital model of statues obtained is not just vivid, but also accurate in the field of surveying and mapping. On this basis, a 3D scene of Jinshan Temple is reconstructed, which proves the validity of the solutions.

Zhang, K.; Li, M.-j.

2014-04-01

86

GLIMPSE: accurate 3D weak lensing reconstructions using sparsity  

Science.gov (United States)

We present GLIMPSE - Gravitational Lensing Inversion and MaPping with Sparse Estimators - a new algorithm to generate density reconstructions in three dimensions from photometric weak lensing measurements. This is an extension of earlier work in one dimension aimed at applying compressive sensing theory to the inversion of gravitational lensing measurements to recover 3D density maps. Using the assumption that the density can be represented sparsely in our chosen basis - 2D transverse wavelets and 1D line-of-sight Dirac functions - we show that clusters of galaxies can be identified and accurately localized and characterized using this method. Throughout, we use simulated data consistent with the quality currently attainable in large surveys. We present a thorough statistical analysis of the errors and biases in both the redshifts of detected structures and their amplitudes. The GLIMPSE method is able to produce reconstructions at significantly higher resolution than the input data; in this paper, we show reconstructions with 6 times finer redshift resolution than the shear data. Considering cluster simulations with 0.05 ? zcl ? 0.75 and 3 × 1013 ? Mvir ? 1015 h-1 M?, we show that the redshift extent of detected peaks is typically 1-2 pixel, or ?z ? 0.07, and that we are able to recover an unbiased estimator of the redshift of a detected cluster by considering many realizations of the noise. We also recover an accurate estimator of the mass, which is largely unbiased when the redshift is known and whose bias is constrained to ?5 per cent in the majority of our simulations when the estimated redshift is taken to be the true redshift. This shows a substantial improvement over earlier 3D inversion methods, which showed redshift smearing with a typical standard deviation of ? ˜ 0.2-0.3, a significant damping of the amplitude of the peaks detected, and a bias in the detected redshift.

Leonard, Adrienne; Lanusse, François; Starck, Jean-Luc

2014-05-01

87

3-D RECONSTRUCTION FROM NARROW-ANGLE RADIOGRAPHS  

International Nuclear Information System (INIS)

So as to detect and characterize potential defects in pipes, inspections are carried out with the help of non-destructive examination techniques (NDE) including x- or ? radiography. Should a defect be detected, one can be asked to prove the component still stands the mechanical constraints. In these cases of expertise, the use of a 3-D reconstruction processing technique can be very useful. One characteristic of such applications is that, in general the number and angles of projections are very limited and the data are very noisy, so classical tomography algorithms cannot solve the problem. In this work, we study two methods of reconstruction that allows to take the specificity of radiography inspection into account through two different means: a reconstruction technique based on a priori model (Markov-Potts), a binary technique that constrain the solution to be either 0 or 1 and called 'BLMR'. This paper focuses on first results we obtain on simulated data and real data corresponding to a mock-up with several electro-dynamically manufactured cylindrical defects

2008-02-28

88

Enhanced imaging of microcalcifications in digital breast tomosynthesis through improved image-reconstruction algorithms  

CERN Multimedia

PURPOSE: We develop a practical, iterative algorithm for image-reconstruction in under-sampled tomographic systems, such as digital breast tomosynthesis (DBT). METHOD: The algorithm controls image regularity by minimizing the image total $p$-variation (TpV), a function that reduces to the total variation when $p=1.0$ or the image roughness when $p=2.0$. Constraints on the image, such as image positivity and estimated projection-data tolerance, are enforced by projection onto convex sets (POCS). The fact that the tomographic system is under-sampled translates to the mathematical property that many widely varied resultant volumes may correspond to a given data tolerance. Thus the application of image regularity serves two purposes: (1) reduction of the number of resultant volumes out of those allowed by fixing the data tolerance, finding the minimum image TpV for fixed data tolerance, and (2) traditional regularization, sacrificing data fidelity for higher image regularity. The present algorithm allows for this...

Sidky, Emil Y; Reiser, Ingrid S; Nishikawa, Robert M; Moore, Richard H; Kopans, Daniel B

2009-01-01

89

The interactive presentation of 3D information obtained from reconstructed datasets and 3D placement of single histological sections with the 3D portable document format  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Interpretation of the results of anatomical and embryological studies relies heavily on proper visualization of complex morphogenetic processes and patterns of gene expression in a three-dimensional (3D) context. However, reconstruction of complete 3D datasets is time consuming and often researchers study only a few sections. To help in understanding the resulting 2D data we developed a program (TRACTS) that places such arbitrary histological sections into a high-resolution 3D model of the de...

Boer, Bouke A.; Soufan, Alexandre T.; Hagoort, Jaco; Mohun, Timothy J.; Den Hoff, Maurice J. B.; Hasman, Arie; Voorbraak, Frans P. J. M.; Moorman, Antoon F. M.; Ruijter, Jan M.

2011-01-01

90

3D Lunar Terrain Reconstruction from Apollo Images  

Science.gov (United States)

Generating accurate three dimensional planetary models is becoming increasingly important as NASA plans manned missions to return to the Moon in the next decade. This paper describes a 3D surface reconstruction system called the Ames Stereo Pipeline that is designed to produce such models automatically by processing orbital stereo imagery. We discuss two important core aspects of this system: (1) refinement of satellite station positions and pose estimates through least squares bundle adjustment; and (2) a stochastic plane fitting algorithm that generalizes the Lucas-Kanade method for optimal matching between stereo pair images.. These techniques allow us to automatically produce seamless, highly accurate digital elevation models from multiple stereo image pairs while significantly reducing the influence of image noise. Our technique is demonstrated on a set of 71 high resolution scanned images from the Apollo 15 mission

Broxton, Michael J.; Nefian, Ara V.; Moratto, Zachary; Kim, Taemin; Lundy, Michael; Segal, Alkeksandr V.

2009-01-01

91

Wide-angle breast tomosynthesis: initial comparative evaluation  

Science.gov (United States)

Conventional mammography is largely limited by superimposed anatomy which is alleviated by breast tomosynthesis and CT. Limited acquisition in tomosynthesis can result in significant out of plane artifacts while large angular acquisition span in CT can limit the imaging coverage of the chest wall near the breast. We propose a new breast imaging modality, wide-angle breast tomosynthesis (WBT), aimed to provide a practical compromise between 3D sampling and chest-wall coverage. This study compares lesion detection between conventional digital breast tomosynthesis, WBT, and breast CT (44°, 99°, and 198° total angle range, respectively) under equal patient dose conditions. A Monte Carlo (MC) code based on the Penelope package modeled a virtual flat-panel breast tomosynthesis system. The modalities were simulated at four breast compression levels. Glandular dose to the breast was estimated and the radiation flux was subsequently adjusted to achieve a constant mean glandular dose level of 1.5 mGy, independent of the breast thickness and acquisition geometry. Reconstructed volumes were generated using iterative reconstruction methods. Lesion detectability was estimated using contrast-to-noise-ratio. Results showed improved detection with increased angular span and compression. Evaluations also showed improved performance of WBT over DBT at lower compression levels, therefore highlighting potential for reduced breast compression when using a larger acquisition angle.

Thompson, John; Chen, Baiyu; Richard, Samuel; Bowsher, James; Samei, Ehsan

2010-03-01

92

Contributions to the 3D city modeling : 3D polyhedral building model reconstruction from aerial images and 3D facade modeling from terrestrial 3D point cloud and images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this work is to develop research on 3D building modeling. In particular, the research in aerial-based 3D building reconstruction is a topic very developed since 1990. However, it is necessary to pursue the research since the actual approaches for 3D massive building reconstruction (although efficient) still encounter problems in generalization, coherency, accuracy. Besides, the recent developments of street acquisition systems such as Mobile Mapping Systems open new perspectives fo...

Hammoudi, Karim

2011-01-01

93

3-D reconstruction for mass lesions in the head and neck  

International Nuclear Information System (INIS)

3-D reconstructions in the head and neck were carried out on 21 normals and 11 patients with space-occupying lesions, both before and after the administration of Gd-DTPA. The 3-D reconstructions were obtained by the 'ray-tracing' method. For the 3-D reconstructions, portions of the skull surface image were removed to permit views of the deeper tissues. The 3-D reconstructions included an hypoglossus neurinoma, a glomus tumour, two carcinomas of the maxillary antra, three naso-pharyngeal carcinomas, a parotid adenoma, an oro-pharyngeal haemangioma and two lesions in the neck. The 3-D reconstructions provided a better understanding of the morphology than was obtained from the two-dimensional images. 3-D reconstructions of lesions in the head and neck will become a valuable diagnostic method for demonstrating space-occupying lesions, particularly with regard to surgical planning. (orig.)

1990-01-01

94

3D fast reconstruction in positron emission tomography; Reconstrucao 3D rapida em tomografia por emissao de positrons  

Energy Technology Data Exchange (ETDEWEB)

The issue of long reconstruction times in positron emission tomography (PET) has been addressed from several points of view, resulting in an affordable dedicated system capable of handling routine 3D reconstructions in a few minutes per frame : on the hardware side using fast processors and a parallel architecture, and on the software side, using efficient implementation of computationally less intensive algorithms 6 refs., 2 figs., 1 tab.

Egger, M.L. [Sao Paulo Univ., SP (Brazil). Instituto do Coracao. Div. de Informatica; Scheurer, A. Hermann; Joseph, C. [Lausanne Univ. (Switzerland). Inst. de Physique Nucleaire; Morel, C. [Geneva Univ. (Switzerland). Hospital. Div. of Nuclear Medicine

1996-12-31

95

Characterization of masses in digital breast tomosynthesis: Comparison of machine learning in projection views and reconstructed slices  

International Nuclear Information System (INIS)

Purpose: In digital breast tomosynthesis (DBT), quasi-three-dimensional (3D) structural information is reconstructed from a small number of 2D projection view (PV) mammograms acquired over a limited angular range. The authors developed preliminary computer-aided diagnosis (CADx) methods for classification of malignant and benign masses and compared the effectiveness of analyzing lesion characteristics in the reconstructed DBT slices and in the PVs. Methods: A data set of MLO view DBT of 99 patients containing 107 masses (56 malignant and 51 benign) was collected at the Massachusetts General Hospital with IRB approval. The DBTs were obtained with a GE prototype system which acquired 11 PVs over a 50 deg. arc. The authors reconstructed the DBTs at 1 mm slice interval using a simultaneous algebraic reconstruction technique. The region of interest (ROI) containing the mass was marked by a radiologist in the DBT volume and the corresponding ROIs on the PVs were derived based on the imaging geometry. The subsequent processes were fully automated. For classification of masses using the DBT-slice approach, the mass on each slice was segmented by an active contour model initialized with adaptive k-means clustering. A spiculation likelihood map was generated by analysis of the gradient directions around the mass margin and spiculation features were extracted from the map. The rubber band straightening transform (RBST) was applied to a band of pixels around the segmented mass boundary. The RBST image was enhanced by Sobel filtering in the horizontal and vertical directions, from which run-length statistics texture features were extracted. Morphological features including those from the normalized radial length were designed to describe the mass shape. A feature space composed of the spiculation features, texture features, and morphological features extracted from the central slice alone and seven feature spaces obtained by averaging the corresponding features from three to 19 slices centered at the central slice were compared. For classification of masses using the PV approach, a feature extraction process similar to that described above for the DBT approach was performed on the ROIs from the individual PVs. Six feature spaces obtained from the central PV alone and by averaging the corresponding features from three to 11 PVs were formed. In each feature space for either the DBT-slice or the PV approach, a linear discriminant analysis classifier with stepwise feature selection was trained and tested using a two-loop leave-one-case-out resampling procedure. Simplex optimization was used to guide feature selection automatically within the training set in each leave-one-case-out cycle. The performance of the classifiers was evaluated by the area (Az) under the receiver operating characteristic curve. Results: The test Az values from the DBT-slice approach ranged from 0.87±0.03 to 0.93±0.02, while those from the PV approach ranged from 0.78±0.04 to 0.84±0.04. The highest test Az of 0.93±0.02 from the nine-DBT-slice feature space was significantly (p=0.006) better than the highest test Az of 0.84±0.04 from the nine-PV feature space. Conclusion: The features of breast lesions extracted from the DBT slices consistently provided higher classification accuracy than those extracted from the PV images.

2010-07-01

96

Methodology for 3D reconstruction of objects for teaching virtual restoration  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we propose a methodology for 3D virtual reconstruction of objects that can be applied to virtual restoration. The methodology is based on an image-based modelling technique and allows generating a textured 3D mesh from a set of images. The proposed methodology consists in the following actions: obtain images of the object, processing of the images, 3D reconstruction of the object, finishing and completing details, restoration of the 3D virtual model. First, we review several frameworks and toolkits that can be used for image-based modelling and then a detail example of 3D reconstruction is presented. The advantage of this methodology for 3D virtual reconstruction is the use of inexpensive equipment, because only common video and computing devices are needed.

Silviu Butnariu

2013-01-01

97

Surface Reconstruction from Sparse and Arbitrarily Oriented Contours in Freehand 3D Ultrasound  

Directory of Open Access Journals (Sweden)

Full Text Available 3D reconstruction for freehand 3D ultrasound is a challenging issue because the recorded B-scans are not only sparse, but also non-parallel (actually they may arbitrarily orient in 3D space and may intersect each other. Conventional volume reconstruction methods can’t reconstruct sparse data efficiently while not introducing geometrical artifacts and conventional surface reconstruction methods can’t reconstruct surfaces from contours that are arbitrarily oriented in 3D space. We developed a new surface reconstruction method for freehand 3D ultrasound based on variational implicit function which is presented by Greg Turk for shape transformation. In the new method, we first constructed on- and off-surface constraints from the segmented contours of all recorded B-scans and then used a variational interpolation technique to get a single implicit function in 3D. Finally, the implicit function was evaluated to extract the zero-valued surface as final reconstruction result. Two experiments was conducted to assess our variational surface reconstruction method and the experiment results have shown that the new method is capable of reconstructing surface smoothly from sparse contours which can be arbitrarily oriented in 3D space.

Shuangcheng Deng

98

3D reconstruction of the coronary tree usig Biplane Snakes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Esta tesis explora los problemas de la reconstrucción 3D de los vasos coronarios a partir de angiografías: calibración, extracción de los vasos a partir de las imágenes, y reconstrucción 3D del vaso. La calibración se divide en dos procedimientos: El primer procedimiento corrige la distorsión geométrica, y el segundo se concentra en la estimación de los parámetros extrínsecos e intrínsicos del sistema de adquisición. La distorsión geométrica} introducida por el intensificador ...

Can?ero Morales, Cristina

2003-01-01

99

Improving architectural 3D reconstruction by constrained modelling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This doctoral thesis presents new techniques for improving the structural quality of automatically-acquired architectural 3D models. Common architectural properties such as parallelism and orthogonality of walls and linear structures are exploited. The locations of features such as planes and 3D lines are extracted from the model by using a probabilistic technique (RANSAC). The relationships between the planes and lines are inferred automatically using a knowledge-based archite...

Cantzler, Helmut

2003-01-01

100

Fully 3D Monte Carlo reconstruction in SPECT: proof of concept and is it worthwhile?  

International Nuclear Information System (INIS)

In Single Photon Emission Computed Tomography (SPECT) with parallel hole collimation, image reconstruction is usually performed as a set of 2D analytical or iterative reconstructions. This approach ignores the 3D nature of scatter and detector response function that affect the detected signal. To deal with the 3D nature of the image formation process, iterative reconstruction can be used by considering a 3D projector modeling the 3D spread of photons. This has already been studied using approximate analytical models for the 3D projector. In this paper, we investigate the value of using accurate Monte Carlo simulations to determine the 3D projector including all physical effects affecting the imaging process (attenuation, scatter, camera point spread function) used in a fully 3D Monte Carlo (F3DMC) reconstruction approach. Given the 3D projector, the reconstruction problem is solved using the maximum likelihood expectation maximization (MLEM) algorithm. To validate the concept, 2 small datasets were simulated and 4 reconstruction strategies were compared: filtered backprojection, MLEM without attenuation correction, MLEM including all corrections with approximate analytical models (MLEMC) and F3DMC. Results suggest that F3DMC multiplies imaging sensitivity by about 103, increases signal-to-noise ratio by 25 to 70% compared to MLEMC and improves spatial resolution. The practical feasibility of the approach on real data sets is discussed. Index Terms - Image reconstruction, Monte Carlo simulations, SPECT. (authors)

2003-07-04

 
 
 
 
101

A storage method of 3D CT image reconstruction system  

International Nuclear Information System (INIS)

In order to realize the miniaturization of three-dimensional cone-beam CT image reconstruction system to small-scale, A three-dimensional image reconstruction system based on FPGA is established. The memory bandwidth requirement of the FDK reconstruction algorithms and the data throughput of the storage system which is composed of SDRAM, SRAM and the internal RAM resource of FPGA is introduced. First, based on filtering algorithms and back projection algorithms the memory bandwidth requirement of a three-dimensional cone-beam CT image reconstruction system is studied. Then, a data access scheme is presented, which uses a SDRAM chip as its main storage a SRAM chip as its external cache and the SRAM resources of FPGA as its internal cache.Then, the process of the implementation and the testing methods of the storage scheme is introduced. Finally, data access capacity of the three-dimensional image reconstruction system was tested. Experimental results indicate that: the storage system can achieve a sequential access data rate of 151.9MB/s and a random access data rate of 100MB/s. It can satisfy the memory bandwidth requirement of a small-scale three-dimensional image reconstruction system. (authors)

2010-02-01

102

RECONSTRUCCIÓN DE OBJETO 3D A PARTIR DE IMÁGENES CALIBRADAS 3D OBJECT RECONSTRUCTION WITH CALIBRATED IMAGES  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabajo presenta el desarrollo de un sistema de reconstrucción de objeto 3D, a partir de una colección de vistas. El sistema se compone de dos módulos principales. El primero realiza el procesamiento de imagen, cuyo objetivo es determinar el mapa de profundidad en un par de vistas, donde cada par de vistas sucesivas sigue una secuencia de fases: detección de puntos de interés, correspondencia de puntos y reconstrucción de puntos; en el proceso de reconstrucción se determinan los parámetros que describen el movimiento (matriz de rotación R y el vector de traslación T entre las dos vistas. Esta secuencia de pasos se repite para todos los pares de vista sucesivas del conjunto. El segundo módulo tiene como objetivo crear el modelo 3D del objeto, para lo cual debe determinar el mapa total de todos los puntos 3D generados; en cada iteración del módulo anterior, una vez obtenido el mapa de profundidad total, genera la malla 3D, aplicando el método de triangulación de Delaunay [28]. Los resultados obtenidos del proceso de reconstrucción son modelados en un ambiente virtual VRML para obtener una visualización más realista del objeto.The system is composed of two main modules. The first one, carries out the image prosecution, whose objective is to determine the depth map of a pair of views where each pair of successive views continues a sequence of phases: interest points detection, points correspondence and points reconstruction; in the reconstruction process, is determined the parameters that describe the movement (rotation matrix R and the translation vector T between the two views. This an sequence of steps is repeated for all the peers of successive views of the set. The second module has as objective to create the 3D model of the object, for it should determine the total map of all the 3D points generated, by each iteration of the previous module, once obtained the map of total depth generates the 3D netting, applying the triangulation method of Delaunay [28]. The results obtained of the reconstruction process are shaped in a VRML virtual environment, to obtain a viewing more realist of the object.

Natividad Grandón-Pastén

2007-08-01

103

Cone-Convolution method for directly image reconstruction of cone-beam 3-D CT system  

International Nuclear Information System (INIS)

The theories and methods of directly 3-D image reconstruction from projections for 3-D CT system are the international front end research projects of modern CT technology. For the single circle source cone-beam 3-D CT system, which has both advantages in structure and disadvantages in incomplete projection data, a new 3-D direct image reconstruction method called 'Cone-Convolution' has been developed. The computer simulation shows that the new method can get much better result than traditional method. The fundamentals of the Cone-Convolution method, the approach steps and some related computer simulation results are expressed

1992-09-01

104

3D surface reconstruction from multiview photographic images using 2D edge contours  

Science.gov (United States)

Most techniques for reconstructing 3D shapes from multi-view 2D photographic images require a large number of images. In this paper, we present a new method for reconstructing 3D surfaces, represented by sets of polygons, using a small number, e.g. 10, of 2D photographic images with full prior knowledge of camera configurations. The method is automatic. Unlike most currently available silhouette-based multiview reconstruction methods, 3D surface points and surfaces are reconstructed directly from 2D edges without costly intermediate voxel reconstruction. The surfaces reconstructed by the proposed method are self-optimized. More surface points and polygons are automatically generated on highly curved parts of a surface. Experiments on computer generated objects and real physical objects were conducted to verify the method. [Figure not available: see fulltext.

Prakoonwit, Simant; Benjamin, Ralph

2012-12-01

105

3D Reconstruction of SPM Probes by Electron Tomography  

International Nuclear Information System (INIS)

Three-dimensional morphological and compositional structures of tungsten tips consisting of layered amorphous oxide shell and crystalline W core are reconstructed by electron tomography using both coherent and incoherent imaging modes. The fidelity of the reconstruction is dependent on three criteria, suppression of unwanted crystal orientation contrast in the crystalline core, nonlinear intensity-thickness relations above a certain thickness limit, and artefacts due to missing angular ranges when acquiring a tilt series of images. Annular dark field (ADF), and EDX chemical mapping are discussed as alternatives to standard bright field (BF) TEM imaging

2007-04-01

106

Analytic 3D image reconstruction using all detected events  

International Nuclear Information System (INIS)

We present the results of testing a previously presented algorithm for three-dimensional image reconstruction that uses all gamma-ray coincidence events detected by a PET volume-imaging scanner. By using two iterations of an analytic filter-backprojection method, the algorithm is not constrained by the requirement of a spatially invariant detector point spread function, which limits normal analytic techniques. Removing this constraint allows the incorporation of all detected events, regardless of orientation, which improves the statistical quality of the final reconstructed image

1988-11-09

107

A sensitivity analysis on 3D velocity reconstruction from multiple registered echo Doppler views.  

Science.gov (United States)

We present a new method for reconstructing a 3D+t velocity field from multiple 3D+t colour Doppler images. Our technique reconstructs 3D velocity vectors from registered multiple standard 3D colour Doppler views, each of which contains a 1D projection of the blood velocity. Reconstruction is based on a scalable patch-wise Least Mean Squares approach, and a continuous velocity field is achieved by using a B-spline grid. We carry out a sensitivity analysis of clinically relevant parameters which affect the accuracy of the reconstruction, including the impact of noise, view angles and registration errors, using simulated data. A realistic simulation framework is achieved by a novel noise model to represent variations in colour Doppler images based on multiscale additive Gaussian noise. Simulations show that, if the Target Registration Error 20° and the standard deviation of noise in the input data is <10 cm/s, the reconstructed velocity field presents visually plausible flow patterns and mean error in flow rate is approximately 10% compared to 2D+t Flow MRI. These results are verified by reconstructing 3D velocity on three healthy volunteers. The technique is applied to reconstruct 3D flow on three paediatric patients showing promising results for clinical application. PMID:23708254

Gomez, Alberto; Pushparajah, Kuberan; Simpson, John M; Giese, Daniel; Schaeffter, Tobias; Penney, Graeme

2013-08-01

108

An efficient Fourier method for 3-D radon inversion in exact cone-beam CT reconstruction.  

Science.gov (United States)

The radial derivative of the three-dimensional (3-D) radon transform of an object is an important intermediate result in many analytically exact cone-beam reconstruction algorithms. We briefly review Grangeat's approach for calculating radon derivative data from cone-beam projections and then present a new, efficient method for 3-D radon inversion, i.e., reconstruction of the image from the radial derivative of the 3-D radon transform, called direct Fourier inversion (DFI). The method is based directly on the 3-D Fourier slice theorem. From the 3-D radon derivative data, which is assumed to be sampled on a spherical grid, the 3-D Fourier transform of the object is calculated by performing fast Fourier transforms (FFT's) along radial lines in the radon space. Then, an interpolation is performed from the spherical to a Cartesian grid using a 3-D gridding step in the frequency domain. Finally, this 3-D Fourier transform is transformed back to the spatial domain via 3-D inverse FFT. The algorithm is computationally efficient with complexity in the order of N3 logN. We have done reconstructions of simulated 3-D radon derivative data assuming sampling conditions and image quality requirements similar to those in medical computed tomography (CT). PMID:9688156

Schaller, S; Flohr, T; Steffen, P

1998-04-01

109

RECONSTRUCCIÓN DE OBJETO 3D A PARTIR DE IMÁGENES CALIBRADAS / 3D OBJECT RECONSTRUCTION WITH CALIBRATED IMAGES  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Este trabajo presenta el desarrollo de un sistema de reconstrucción de objeto 3D, a partir de una colección de vistas. El sistema se compone de dos módulos principales. El primero realiza el procesamiento de imagen, cuyo objetivo es determinar el mapa de profundidad en un par de vistas, donde cada p [...] ar de vistas sucesivas sigue una secuencia de fases: detección de puntos de interés, correspondencia de puntos y reconstrucción de puntos; en el proceso de reconstrucción se determinan los parámetros que describen el movimiento (matriz de rotación R y el vector de traslación T) entre las dos vistas. Esta secuencia de pasos se repite para todos los pares de vista sucesivas del conjunto. El segundo módulo tiene como objetivo crear el modelo 3D del objeto, para lo cual debe determinar el mapa total de todos los puntos 3D generados; en cada iteración del módulo anterior, una vez obtenido el mapa de profundidad total, genera la malla 3D, aplicando el método de triangulación de Delaunay [28]. Los resultados obtenidos del proceso de reconstrucción son modelados en un ambiente virtual VRML para obtener una visualización más realista del objeto. Abstract in english The system is composed of two main modules. The first one, carries out the image prosecution, whose objective is to determine the depth map of a pair of views where each pair of successive views continues a sequence of phases: interest points detection, points correspondence and points reconstructio [...] n; in the reconstruction process, is determined the parameters that describe the movement (rotation matrix R and the translation vector T) between the two views. This an sequence of steps is repeated for all the peers of successive views of the set. The second module has as objective to create the 3D model of the object, for it should determine the total map of all the 3D points generated, by each iteration of the previous module, once obtained the map of total depth generates the 3D netting, applying the triangulation method of Delaunay [28]. The results obtained of the reconstruction process are shaped in a VRML virtual environment, to obtain a viewing more realist of the object.

Grandón-Pastén, Natividad; Aracena-Pizarro, Diego; Tozzi, Clésio Luis.

110

The clinical application of 3D CT reconstruction technique in bone tumor  

International Nuclear Information System (INIS)

Objective: To evaluate the clinical application of 3D CT reconstruction technique in bone tumor. Methods: In total 20 cases with bone tumor were scanned in 2-3 mm collimation and at pitch of 1 using Toshiba Xpress/SX CT scanner. After the scan was completed, 3D reconstruction including SSD and MPR was performed at Sun Sparc station 20 workstation with software Toshiba Xtension 2.01. Results: Quality 3D images were obtained in all 20 cases. The stereoscopy of the tumor and surrounding anatomical structure was well demonstrated in 3D images. Conclusion: Besides axial images, the 3D CT reconstruction including SSD and MPR provides extra information, and helps the qualitative diagnosis of bone tumor. (authors)

2005-09-01

111

Optic flow aided navigation and 3D scene reconstruction  

Science.gov (United States)

An important enabler for low cost airborne systems is the ability to exploit low cost inertial instruments. An Inertial Navigation System (INS) can provide a navigation solution, when GPS is denied, by integrating measurements from inertial sensors. However, the gyrometer and accelerometer biases of low cost inertial sensors cause compound errors in the integrated navigation solution. This paper describes experiments to establish whether (and to what extent) the navigation solution can be aided by fusing measurements from an on-board video camera with measurements from the inertial sensors. The primary aim of the work was to establish whether optic flow aided navigation is beneficial even when the 3D structure within the observed scene is unknown. A further aim was to investigate whether an INS can help to infer 3D scene content from video. Experiments with both real and synthetic data have been conducted. Real data was collected using an AR Parrot quadrotor. Empirical results illustrate that optic flow provides a useful aid to navigation even when the 3D structure of the observed scene is not known. With optic flow aiding of the INS, the computed trajectory is consistent with the true camera motion, whereas the unaided INS yields a rapidly increasing position error (the data represents ~40 seconds, after which the unaided INS is ~50 metres in error and has passed through the ground). The results of the Monte Carlo simulation concur with the empirical result. Position errors, which grow as a quadratic function of time when unaided, are substantially checked by the availability of optic flow measurements.

Rollason, Malcolm

2013-10-01

112

A Parametric Model for Automatic 3D Building Reconstruction from high resolution Satellite Images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This report develops a parametric model for automatic 3D building reconstruction based on a Bayesian approach from PLEIADES simulations. High resolution satellite images are a new kind of data to deal with 3D building reconstruction problems. Their ``relatively low'' resolution and low signal noise ration do not allow to use standard methods developed for the aerial image case. We propose a parametric approach using Digital Elevation Models (DEM) and associated rectangular building footprints...

Lafarge, Florent; Descombes, Xavier; Zerubia, Josiane; Deseilligny, Marc-pierrot

2006-01-01

113

GPU-Based 3D Cone-Beam CT Image Reconstruction for Large Data Volume  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Currently, 3D cone-beam CT image reconstruction speed is still a severe limitation for clinical application. The computational power of modern graphics processing units (GPUs) has been harnessed to provide impressive acceleration of 3D volume image reconstruction. For extra large data volume exceeding the physical graphic memory of GPU, a straightforward compromise is to divide data volume into blocks. Different from the conventional Octree partition method, a new partition scheme is proposed...

Zhao, Xing; Hu, Jing-jing; Zhang, Peng

2009-01-01

114

3D Reconstruction of Natural Underwater Scenes Using the Stereovision System IRIS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study is to propose a 3-dimension reconstruction method of small-scale scenes improved by a new image acquisition method for quantitative measurements. A stereovision system is used to acquire images in order to obtain several shots of an object, at regular intervals according to a predefined trajectory. A complete methodology of 3D reconstruction is exposed to perform a dense 3D model with texture mapping. A first result on natural images collected with the stereovision syste...

Brandou, Vincent; Allais, Anne-gaelle; Perrier, Michel; Malis, E.; Rives, P.; Sarrazin, Jozee; Sarradin, Pierre-marie

2007-01-01

115

Micro-CT for nondestructive 3D reconstruction of MEMS and sensors  

Science.gov (United States)

The combination of x-ray microscopy with tomographical reconstruction allows getting 3D information about the internal microstructure by a non-destructive way. A desktop high- resolution X-ray micro-CT (microtomograph) has been developed for 3D reconstruction and realistic visualization of the internal microstructure with spatial resolution in the micron range. The instrument was successfully tested for inspection, defectoscopy and back engineering in MEMS and integrated multichip sensors.

Sasov, Alexander

2001-04-01

116

3D Reconstruction and Restoration Monitoring of Sculptural Artworks by a Multi-Sensor Framework  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays, optical sensors are used to digitize sculptural artworks by exploiting various contactless technologies. Cultural Heritage applications may concern 3D reconstructions of sculptural shapes distinguished by small details distributed over large surfaces. These applications require robust multi-view procedures based on aligning several high resolution 3D measurements. In this paper, the integration of a 3D structured light scanner and a stereo photogrammetric sensor is proposed with the...

2012-01-01

117

Automated Reconstruction Algorithm for Identification of 3D Architectures of Cribriform Ductal Carcinoma In Situ  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ductal carcinoma in situ (DCIS) is a pre-invasive carcinoma of the breast that exhibits several distinct morphologies but the link between morphology and patient outcome is not clear. We hypothesize that different mechanisms of growth may still result in similar 2D morphologies, which may look different in 3D. To elucidate the connection between growth and 3D morphology, we reconstruct the 3D architecture of cribriform DCIS from resected patient material. We produce a fully automated algorith...

Norton, Kerri-ann; Namazi, Sameera; Barnard, Nicola; Fujibayashi, Mariko; Bhanot, Gyan; Ganesan, Shridar; Iyatomi, Hitoshi; Ogawa, Koichi; Shinbrot, Troy

2012-01-01

118

Use of enhancement algorithm to suppress reflections in 3-D reconstructed capsule endoscopy images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In capsule endoscopy (CE), there is research to develop hardware that enables ‘‘real’’ three-dimensional (3-D) video. However, it should not be forgotten that ‘‘true’’ 3-D requires dual video images. Inclusion of two cameras within the shell of a capsule endoscope though might be unwieldy at present. Therefore, in an attempt to approximate a 3-D reconstruction of the digestive tract surface, a software that recovers information-using gra...

Anastasios Koulaouzidis; Alexandros Karargyris

2013-01-01

119

Experimental validation of a three-dimensional linear system model for breast tomosynthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A three-dimensional (3D) linear model for digital breast tomosynthesis (DBT) was developed to investigate the effects of different imaging system parameters on the reconstructed image quality. In the present work, experimental validation of the model was performed on a prototype DBT system equipped with an amorphous selenium (a-Se) digital mammography detector and filtered backprojection (FBP) reconstruction methods. The detector can be operated in either full resolution with 85 ?m pixel siz...

Zhao, Bo; Zhou, Jun; Hu, Yue-houng; Mertelmeier, Thomas; Ludwig, Jasmina; Zhao, Wei

2009-01-01

120

3D Fractal reconstruction of terrain profile data based on digital elevation model  

International Nuclear Information System (INIS)

Digital Elevation Model (DEM) often makes it difficult for terrain reconstruction and data storage due to the failure in acquisition of details with higher resolution. If original terrain of DEM can be simulated, resulting in geographical details can be represented precisely while reducing the data size, then an effective reconstruction scheme is essential. This paper adopts two sets of real-world 3D terrain profile data to proceed data reducing, i.e. data sampling randomly, then reconstruct them through 3D fractal reconstruction. Meanwhile, the quantitative and qualitative difference generated from different reduction rates were evaluated statistically. The research results show that, if 3D fractal interpolation method is applied to DEM reconstruction, the higher reduction rate can be obtained for DEM of larger data size with respect to that of smaller data size under the assumption that the entire terrain structure is still maintained.

2009-05-30

 
 
 
 
121

Fully 3D Monte Carlo image reconstruction in SPECT using functional regions  

CERN Multimedia

Image reconstruction in Single Photon Emission Computed Tomography (SPECT) is affected by physical effects such as photon attenuation, Compton scatter and detector response. These effects can be compensated for by modeling the corresponding spread of photons in 3D within the system matrix used for tomographic reconstruction. The fully 3D Monte Carlo (F3DMC) reconstruction technique consists in calculating this system matrix using Monte Carlo simulations. The inverse problem of tomographic reconstruction is then solved using conventional iterative algorithms such as maximum likelihood expectation maximization (MLEM). Although F3DMC has already shown promising results, its use is currently limited by two major issues: huge size of the fully 3D system matrix and long computation time required for calculating a robust and accurate system matrix. To address these two issues, we propose to calculate the F3DMC system matrix using a spatial sampling matching the functional regions to be reconstructed. In this approac...

Bitar, Z E; Coello, C; Breton, V; Hill, D; Buvat, I

2006-01-01

122

Reconstruction of 3D medical image by computer graphics  

International Nuclear Information System (INIS)

Recently there are a lot of reports of 3-Dimensional Medical Imaging from CT (Computed Tomography) using Computer Graphics technology. By the way, the greater part of them use Semi-Transparent or cutout-display algorhythm to display 3D images of objects is human body. But these algorhythm can not display figure so clearly that operater can recognize location of target and around organisms at same time. But it is necessary in medical use computer graphics. This paper reports an animation-method in order to display cerebral tumor in human brain. This animation plays a set of multiplex cutout-display frames. The cutout-display exceeds to present inside data only on cutout plain. So, many cutout-display images can present many inside data. Animation is one of effective method to display a lot of frames. And automatic or manual-operation playback of animation made it to be able to present inner structure effectively. (author)

1988-01-01

123

Reconstruction of 3D morphology of polyhedral nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

The three-dimensional (3D) faceting morphology of ceria nanoparticles is analysed using transmission electron microscopy (TEM)-based computed tomography on the nanometre scale. A novel tomography mode of electron energy loss spectroscopic imaging using a single energy window for inelastically scattered electrons is introduced and found to be reliable and fast for freestanding nanoparticles. To compare the new tomographic method with other methods, we provide the first comprehensive application of three complementary TEM-based imaging techniques, including bright field TEM and annular dark field specific TEM (STEM). Traditional bright-field TEM tomography is found to be applicable, in spite of obvious artefacts, for crystalline particles of constant composition. However, the safest interpretation is achieved by a combined recording of bright field and spectroscopic images.

Xu Xiaojing; Saghi, Zineb; Gay, Ralph; Moebus, Guenter [Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

2007-06-06

124

Preoperative Planning Using 3D Reconstructions and Virtual Endoscopy for Location of the Frontal Sinus  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Computed tomography (TC generated tridimensional (3D reconstructions allow the observation of cavities and anatomic structures of our body with detail. In our specialty there have been attempts to carry out virtual endoscopies and laryngoscopies. However, such application has been practically abandoned due to its complexity and need for computers with high power of graphic processing. Objective: To demonstrate the production of 3D reconstructions from CTs of patients in personal computers, with a free specific program and compare them to the surgery actual endoscopic images. Method: Prospective study in which the CTs proper files of 10 patients were reconstructed with the program Intage Realia, version 2009, 0, 0, 702 (KGT Inc., Japan. The reconstructions were carried out before the surgeries and a virtual endoscopy was made to assess the recess and frontal sinus region. After this study, the surgery was digitally performed and stored. The actual endoscopic images of the recess and frontal sinus region were compared to the virtual images. Results: The 3D reconstruction and virtual endoscopy were made in 10 patients submitted to the surgery. The virtual images had a large resemblance with the actual surgical images. Conclusion: With relatively simple tools and personal computer, we demonstrated the possibility to generate 3D reconstructions and virtual endoscopies. The preoperative knowledge of the frontal sinus natural draining path location may generate benefits during the performance of surgeries. However, more studies must be developed for the evaluation of the real roles of such 3D reconstructions and virtual endoscopies.

Abreu, João Paulo Saraiva

2011-01-01

125

Neurofunctional systems. 3D reconstructions with correlated neuroimaging  

Energy Technology Data Exchange (ETDEWEB)

This book introduces, for the first time, computer-generated images of the neurofunctional systems of the human brain. These images are more accurate than drawings. The main views presented are of the medial lemniscus system, auditory system, visual system, basal ganglia, corticospinal system, and the limbic system. The arteries and sulci of the cerebral hemispheres are also illustrated by computer. These images provide a three-dimensional orientation of the intracranial space and help, for example, to assess vascular functional disturbance of the brain. Clinicians will find these images valuable for the spatial interpretation of magnetic resonance (MR), computed tomography (CT), and positron emission tomography (PET) images since many neurofunctional systems cannot be visualized as isolated structures in neuroimaging. Computer-assisted surface reconstructions of the neurofunctional systems and the cerebral arteries serve as a basis for constructing these computer-generated images. The surface reconstructions are anatomically realistic having been created from brain sections with minimal deformations. The method of computer graphics, known as ray tracing, produces digital images form these reconstructions. The computer-generated methods are explained. The computer-generated images are accompanied by illustrations and texts on neuroanatomy and clinical practice. The neurofunctional systems of the human brain are also shown in sections so that the reader can mentally reconstruct the neurofunctional systems, thus facilitating the transformation of information into textbooks and atlantes of MR and CT imaging. The aim of this book is acquaint the reader with the three-dimensional aspects of the neurofunctional systems and the cerebral arteries of the human brain using methods of computer graphics. Computer scientists and those interested in this technique are provided with basic neuroanatomic and neurofunctional information. Physicians will have a clearer understanding of the limitations and possibilities of computer graphics in the field of medicine. The three-dimensional aspects of these neurofunctional systems should serve as a tool for clinicians and will appeal to neurologists, neurosurgeons, neuroradiologists, nuclear physicians, neurophysiologists, traumatologists and oncologists. Physicians and students with an interest in neurobiology will also find this an instructive and practical handbook. (orig.)

Kretschmann, H.J.; Fiekert, W.; Gerke, M.; Vogt, H.; Weirich, D.; Wesemann, M. [Medizinische Hochschule Hannover (Germany). Abt. Neuroanatomie; Weinrich, W. [Staedtisches Krankenhaus Nordstadt, Hannover (Germany). Abt. fuer Neurologie

1998-12-31

126

Precipitate shape fitting and reconstruction by means of 3D Zernike functions  

International Nuclear Information System (INIS)

3D Zernike functions are defined and used for the reconstruction of precipitate shapes. These functions are orthogonal over the unit ball and allow for an arbitrary shape, scaled to fit inside an embedding sphere, to be decomposed into 3D harmonics. Explicit expressions are given for the general Zernike moments, correcting typographical errors in the literature. Explicit expressions of the Zernike moments for the ellipsoid and the cube are given. The 3D Zernike functions and moments are applied to the reconstruction of ?' precipitate shapes in two Ni-based superalloys, one with nearly cuboidal precipitate shapes, and one with more complex dendritic shapes

2012-01-01

127

Transnasal Skull Base Reconstruction Using a 3-D Endoscope: Our First Impressions*  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nowadays endoscopic skull base reconstruction is safely and effectively performed by means of two-dimensional (2-D) endoscopic technique. The aim of our study is to compare our 2-D experience with the novel 3-D technology in the field of skull base reconstruction techniques. In this study four patients treated with various kinds of planned duraplasty are included. The new 3-D technology was compared with the high-definition 2-D scopes during the different steps of the procedures. The 3-D endo...

Castelnuovo, Paolo; Battaglia, Paolo; Turri-zanoni, Mario; Volpi, Luca; Bignami, Maurizio; Dallan, Iacopo

2012-01-01

128

Neural Network Based Reconstruction of a 3D Object from a 2D Wireframe  

CERN Multimedia

We propose a new approach for constructing a 3D representation from a 2D wireframe drawing. A drawing is simply a parallel projection of a 3D object onto a 2D surface; humans are able to recreate mental 3D models from 2D representations very easily, yet the process is very difficult to emulate computationally. We hypothesize that our ability to perform this construction relies on the angles in the 2D scene, among other geometric properties. Being able to reproduce this reconstruction process automatically would allow for efficient and robust 3D sketch interfaces. Our research focuses on the relationship between 2D geometry observable in the sketch and 3D geometry derived from a potential 3D construction. We present a fully automated system that constructs 3D representations from 2D wireframes using a neural network in conjunction with a genetic search algorithm.

Johnson, Kyle; Lipson, Hod

2010-01-01

129

Spatial resolution of the HRRT PET scanner using 3D-OSEM PSF reconstruction  

DEFF Research Database (Denmark)

The spatial resolution of the Siemens High Resolution Research Tomograph (HRRT) dedicated brain PET scanner installed at Copenhagen University Hospital (Rigshospitalet) was measured using a point-source phantom with high statistics. Further, it was demonstrated how the newly developed 3D-OSEM PSF reconstruction can improve the resolution in reconstructed images with high signal-to-noise-ratios.

Olesen, Oline Vinter; Jensen, Jørgen Arendt

2009-01-01

130

Two approaches to 3D reconstruction in NMR zeugmatography  

International Nuclear Information System (INIS)

In nuclear magnetic resonance (NMR) zeugmatography, the primary data pertain to integrals of the unknown nuclear spin density f(x,y,z) over planes instead of lines in R3. Two natural approaches to reconstructing f from such data are: (1) By numerical implementation of the inverse Radon transform in three dimensions (the direct approach), and (2) by application, in two successive stages, of existing well-known algorithms for inverting the two-dimensional Radon transform (the two-stage approach). These two approaches are discussed and compared, both from a theoretical standpoint and through computer results obtained with real NMR data. For the cases studied to date the two methods appear to produce qualitatively similar results

1980-02-16

131

Reconstruction of Consistent 3d CAD Models from Point Cloud Data Using a Priori CAD Models  

Science.gov (United States)

We address the reconstruction of 3D CAD models from point cloud data acquired in industrial environments, using a pre-existing 3D model as an initial estimate of the scene to be processed. Indeed, this prior knowledge can be used to drive the reconstruction so as to generate an accurate 3D model matching the point cloud. We more particularly focus our work on the cylindrical parts of the 3D models. We propose to state the problem in a probabilistic framework: we have to search for the 3D model which maximizes some probability taking several constraints into account, such as the relevancy with respect to the point cloud and the a priori 3D model, and the consistency of the reconstructed model. The resulting optimization problem can then be handled using a stochastic exploration of the solution space, based on the random insertion of elements in the con?guration under construction, coupled with a greedy management of the con?icts which ef?ciently improves the con?guration at each step. We show that this approach provides reliable reconstructed 3D models by presenting some results on industrial data sets.

Bey, A.; Chaine, R.; Marc, R.; Thibault, G.; Akkouche, S.

2011-09-01

132

A simple approach for 3D reconstruction of the spine from biplanar radiography  

Science.gov (United States)

This paper proposed a simple approach for 3D spinal reconstruction from biplanar radiography. The proposed reconstruction consisted in reconstructing the 3D central curve of the spine based on the epipolar geometry and automatically aligning vertebrae under the constraint of this curve. The vertebral orientations were adjusted by matching the projections of the 3D pedicles with the 2D pedicles in biplanar radiographs. The user interaction time was within one minute for a thoracic spine. Sixteen pairs of radiographs of a thoracic spinal model were used to evaluate the precision and accuracy. The precision was within 3.1 mm for the location and 3.5° for the orientation. The accuracy was within 3.5 mm for the location and 3.9° for the orientation. These results demonstrate that this approach can be a promising tool to obtain the 3D spinal geometry with acceptable user interactions in scoliotic clinics.

Zhang, Junhua; Shi, Xinling; Lv, Liang; Guo, Fei; Zhang, Yufeng

2014-04-01

133

Fully 3D PET image reconstruction with a 4D sinogram blurring kernel  

International Nuclear Information System (INIS)

Accurately modeling PET system response is essential for high-resolution image reconstruction. Traditionally, sinogram blurring effects are modeled as a 2D blur in each sinogram plane. Such 2D blurring kernel is insufficient for fully 3D PET data, which has four dimensions. In this paper, we implement a fully 3D PET image reconstruction using a 4D sinogram blurring kernel estimated from point source scans and perform phantom experiments to evaluate the improvements in image quality over methods with existing 2D blurring kernels. The results show that the proposed reconstruction method can achieve better spatial resolution and contrast recovery than existing methods. (orig.)

2011-07-11

134

Stereoscopic reconstruction of 3D PIV data in T-junction with circular profile  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper experimental study of flow in T-junction using 3D PIV method is presented. Motion of seeding particles was recorded by a pair of suitably located cameras in precisely defined cross sections of the junction. Based on this information, three-dimensional model of flow in different sections of junction was reconstructed. The reconstruction results from the projection matrixes of each camera, which are obtained from positions of objects in the scene and their projection positions in the image plane. Standard 3D PIV reconstruction was rejected, because of optical distortion in T-Junction.

Jašíková D.

2013-04-01

135

A Novel Method for Radio Propagation Simulation Based on Automatic 3D Environment Reconstruction  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a novel method to simulate radio propagation is presented. The method consists of two steps: automatic 3D scenario reconstruction and propagation modeling. For 3D reconstruction, a machine learning algorithm is adopted and improved to automatically recognize objects in pictures taken from target regions, and 3D models are generated based on the recognized objects. The propagation model employs a ray tracing algorithm to compute signal strength for each point on the constructed 3D map. Our proposition reduces, or even eliminates, infrastructure cost and human efforts during the construction of realistic 3D scenes used in radio propagation modeling. In addition, the results obtained from our propagation model proves to be both accurate and efficient.

D. He

2012-12-01

136

Symmetry-adapted spherical harmonics method for high-resolution 3D single-particle reconstructions.  

Science.gov (United States)

Three-dimensional (3D) reconstruction is the last and an essential step toward high-resolution structural determination in single-particle cryo-electron microscopy (cryoEM). We have implemented a new algorithm for reconstructing 3D structures of macromolecular complexes with icosahedral symmetry from cryoEM images. Icosahedral symmetry-adapted functions (ISAFs) are used to interpolate structural factors in the reciprocal space to generate a 3D reconstruction in spherical coordinates. In our implementation, we introduced a recursive method for deriving higher order ISAFs from three lower order seed functions. We demonstrate improvements of our new method in both the noise suppression and the effective resolution in 3D reconstruction over the commonly used Fourier-Bessel synthesis method introduced by Crowther et al. three decades ago. Our 3D reconstruction method can be extended to macromolecular complexes with other symmetry types and is thus likely to impact future high-resolution cryoEM single-particle reconstruction efforts in general. PMID:17977017

Liu, Hongrong; Cheng, Lingpeng; Zeng, Songjun; Cai, Canying; Zhou, Z Hong; Yang, Qibin

2008-01-01

137

3-d reconstruction of neurons from multichannel confocal laser scanning image series.  

Science.gov (United States)

A confocal laser scanning microscope (CLSM) collects information from a thin, focal plane and ignores out-of-focus information. Scanning of a specimen, with stepwise axial (Z-) movement of the stage in between each scan, produces Z-series of confocal images of a tissue volume, which then can be used to 3-D reconstruct structures of interest. The operator first configures separate channels (e.g., laser, filters, and detector settings) for each applied fluorochrome and then acquires Z-series of confocal images: one series per channel. Channel signal separation is extremely important. Measures to avoid bleaching are vital. Post-acquisition deconvolution of the image series is often performed to increase resolution before 3-D reconstruction takes place. In the 3-D reconstruction programs described in this unit, reconstructions can be inspected in real time from any viewing angle. By altering viewing angles and by switching channels off and on, the spatial relationships of 3-D-reconstructed structures with respect to structures visualized in other channels can be studied. Since each brand of CLSM, computer program, and 3-D reconstruction package has its own proprietary set of procedures, a general approach is provided in this protocol wherever possible. Curr. Protoc. Neurosci 67:2.8.1-2.8.18. © 2014 by John Wiley & Sons, Inc. PMID:24723320

Wouterlood, Floris G

2014-01-01

138

Full 3D-OSEM reconstruction with compressed response of the system  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Small animal PET scanners require high spatial resolution (< 1 mm) and good sensitivity. To obtain high resolution images, iterative reconstruction methods, like OSEM, applied to image reconstruction in three-dimensional (3D) positron emission tomography (PET), have superior performance over analytical reconstruction algorithms like FBP. However, the high computational cost of iterative methods remains a serious drawback to their development and clinical routine use. The increase in per...

Herraiz Lo?pez, J.; Espan?a, Samuel; Vaquero, Juan Jose?; Desco, Manuel; Udi?as, Jose? Manuel

2004-01-01

139

Progressive 3D reconstruction of unknown objects using one eye-in-hand camera  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a complete 3D-reconstruction method optimized for online object modeling in the context of object grasping by a robot hand. The proposed solution is based on images captured by an eye-in-hand camera mounted on the robot arm and is an original combination of classical but simplified reconstruction methods. The different techniques used form a process that offers fast, progressive and reactive reconstruction of the object.

Walck, Guillaume; Drouin, Michel

2010-01-01

140

Parallel OSEM Reconstruction Algorithm for Fully 3-D SPECT on a Beowulf Cluster.  

Science.gov (United States)

In order to improve the computation speed of ordered subset expectation maximization (OSEM) algorithm for fully 3-D single photon emission computed tomography (SPECT) reconstruction, an experimental beowulf-type cluster was built and several parallel reconstruction schemes were described. We implemented a single-program-multiple-data (SPMD) parallel 3-D OSEM reconstruction algorithm based on message passing interface (MPI) and tested it with combinations of different number of calculating processors and different size of voxel grid in reconstruction (64×64×64 and 128×128×128). Performance of parallelization was evaluated in terms of the speedup factor and parallel efficiency. This parallel implementation methodology is expected to be helpful to make fully 3-D OSEM algorithms more feasible in clinical SPECT studies. PMID:17282575

Rong, Zhou; Tianyu, Ma; Yongjie, Jin

2005-01-01

 
 
 
 
141

3D Image Reconstruction for Implosion Pellet in ICF Experiment Based on Iterative Algorithms  

Directory of Open Access Journals (Sweden)

Full Text Available The projection images of implosion-pellet captured by framing cameras or pinhole cameras are two-dimensional in the inertia confinement fusion experiments. Since the two-dimensional images are lack of the depth information, therefore they are hardly used to diagnose the compression symmetry of the implosion-pellet, the 3D image of the implosion-pellet reconstructed from their two-dimensional projection images can overcome these problems. As the iterative algorithms can reconstruct the original 3D image from just a few projections with good noise suppression, three iterative algorithms which are commonly applied in CT image reconstruction filed are utilized to the reconstruct 3D image of implosion-pellet. The numerical simulations show that the algebraic reconstruction technique algorithm performs best under the condition that the projection images are ‘incomplete’ and noise free or with not so heavy noise. When there are heavy noise in the projection images the simultaneous iterative reconstruction technique surpasses the other algorithms, which is proved to be more competent for the 3D image reconstruction of implosion-pellet in inertia confinement fusion experiment.

Xishun Liu

2013-01-01

142

3D Reconstruction of a Rotating Erupting Prominence  

Science.gov (United States)

A bright prominence associated with a coronal mass ejection (CME) was seen erupting from the Sun on 9 April 2008. This prominence was tracked by both the Solar Terrestrial Relations Observatory (STEREO) EUVI and COR1 telescopes, and was seen to rotate about the line of sight a it erupted; therefore, the event has been nicknamed the "Cartwheel CME." The threads of the prominence in the core of the CME quite clearly indicate the structure of a weakly to moderately twisted flux rope throughout the field of view, up to heliocentric heights of 4 solar radii. Although the STEREO separation was 48 deg, it was possible to match some sharp features in the later part of the eruption as seen in the 304 A line in EUVI and in the H-alpha-sensitive bandpass of COR I by both STEREO Ahead and Behind. These features could then be traced out in three-dimensional space, and reprojected into a view in which the eruption is directed toward the observer. The reconstructed view shows that the alignment of the prominence to the vertical axis rotates as it rises up to a leading-edge height of approximately equal to 2.5 solar radii, and then remains approximately constant. The alignment at 2.5 solar radii differs by about 115 deg from the original filament orientation inferred from H-alpha and EUV data, and the height profile of the rotation, obtained here for the first time, shows that two thirds of the total rotation are reached within approximately equal to 0.5 solar radii above the photosphere. These features are well reproduced by numerical simulations of an unstable moderately twisted flux rope embedded in external flux with a relatively strong shear field component.

Thompson, W. T.; Kliem, B.; Toeroek, T.

2011-01-01

143

IVUSAngio tool: a publicly available software for fast and accurate 3D reconstruction of coronary arteries.  

Science.gov (United States)

There is an ongoing research and clinical interest in the development of reliable and easily accessible software for the 3D reconstruction of coronary arteries. In this work, we present the architecture and validation of IVUSAngio Tool, an application which performs fast and accurate 3D reconstruction of the coronary arteries by using intravascular ultrasound (IVUS) and biplane angiography data. The 3D reconstruction is based on the fusion of the detected arterial boundaries in IVUS images with the 3D IVUS catheter path derived from the biplane angiography. The IVUSAngio Tool suite integrates all the intermediate processing and computational steps and provides a user-friendly interface. It also offers additional functionality, such as automatic selection of the end-diastolic IVUS images, semi-automatic and automatic IVUS segmentation, vascular morphometric measurements, graphical visualization of the 3D model and export in a format compatible with other computer-aided design applications. Our software was applied and validated in 31 human coronary arteries yielding quite promising results. Collectively, the use of IVUSAngio Tool significantly reduces the total processing time for 3D coronary reconstruction. IVUSAngio Tool is distributed as free software, publicly available to download and use. PMID:24209925

Doulaverakis, Charalampos; Tsampoulatidis, Ioannis; Antoniadis, Antonios P; Chatzizisis, Yiannis S; Giannopoulos, Andreas; Kompatsiaris, Ioannis; Giannoglou, George D

2013-11-01

144

Comparison of Parallel MRI Reconstruction Methods for Accelerated 3D Fast Spin-Echo Imaging  

Science.gov (United States)

Parallel MRI (pMRI) achieves imaging acceleration by partially substituting gradient-encoding steps with spatial information contained in the component coils of the acquisition array. Variable-density subsampling in pMRI was previously shown to yield improved two-dimensional (2D) imaging in comparison to uniform subsampling, but has yet to be used routinely in clinical practice. In an effort to reduce acquisition time for 3D fast spin-echo (3D-FSE) sequences, this work explores a specific nonuniform sampling scheme for 3D imaging, subsampling along two phase-encoding (PE) directions on a rectilinear grid. We use two reconstruction methods—2D-GRAPPA-Operator and 2D-SPACE RIP—and present a comparison between them. We show that high-quality images can be reconstructed using both techniques. To evaluate the proposed sampling method and reconstruction schemes, results via simulation, phantom study, and in vivo 3D human data are shown. We find that fewer artifacts can be seen in the 2D-SPACE RIP reconstructions than in 2D-GRAPPA-Operator reconstructions, with comparable reconstruction times.

Xiao, Zhikui; Hoge, W. Scott; Mulkern, R.V.; Zhao, Lei; Hu, Guangshu; Kyriakos, Walid E.

2014-01-01

145

Morphological evolution of a 3D CME cloud reconstructed from three viewpoints  

CERN Document Server

The propagation properties of coronal mass ejections (CMEs) are crucial to predict its geomagnetic effect. A newly developed three dimensional (3D) mask fitting reconstruction method using coronagraph images from three viewpoints has been described and applied to the CME ejected on August 7, 2010. The CME's 3D localisation, real shape and morphological evolution are presented. Due to its interaction with the ambient solar wind, the morphology of this CME changed significantly in the early phase of evolution. Two hours after its initiation, it was expanding almost self-similarly. CME's 3D localisation is quite helpful to link remote sensing observations to in situ measurements. The investigated CME was propagating to Venus with its flank just touching STEREO B. Its corresponding ICME in the interplanetary space shows a possible signature of a magnetic cloud with a preceding shock in VEX observations, while from STEREO B only a shock is observed. We have calculated three principle axes for the reconstructed 3D ...

Feng, L; Wei, Y; Gan, W Q; Zhang, T L; Wang, M Y

2012-01-01

146

3D Reconstruction of Ultrasonic Images Based on Matlab/Simulink  

Directory of Open Access Journals (Sweden)

Full Text Available In this study we use Matlab/Simulink as a user friendly interface to examine three recent works on UT image processing; furthermore a new method based on morphological features is proposed. A series of simulated 2D UT images of two known cysts are processed by the 4 different methods. They will serve as the input for 3D surface reconstruction package. A novel comparison way related to 2D and 3D features of cysts is provided. The weakness, the advantages and the deficiencies of each method are explained for cyst 3D reconstruction. It is shown that our novel morphological based method has good performance for online reconstruction specially.

Asad Babakhani

2006-01-01

147

3D building reconstruction from aerial CCD image and sparse laser sample data  

Science.gov (United States)

An approach for 3D building reconstruction automatically based on aerial CCD image and sparse laser scanning sample points is presented in this paper. The geometry shape of a building is shown very clearly in the aerial high-resolution CCD image, so we use Laplacian sharpening operator and threshold segmentation to extract the edges of CCD image first, and then pixel connectivity is used to extract the linear features in the CCD image. Bi-direction projection histogram and line matching are proposed to extract the contours of buildings. The height of the building is determined from sparse laser sample points which are within the contour of the buildings extracted from CCD image; therefore the 3D information of each building is reconstructed. We reconstruct 3D buildings correctly by this approach using real aerial CCD and sparse laser rangefinder data.

Hongjian, You; Shiqiang, Zhang

2006-06-01

148

Real-Time Camera Tracking and 3D Reconstruction Using Signed Distance Functions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ability to quickly acquire 3D models is an essential capability needed in many disciplines including robotics, computer vision, geodesy, and architecture. In this paper we present a novel method for real-time camera tracking and 3D reconstruction of static indoor environments using an RGB-D sensor. We show that by representing the geometry with a signed distance function (SDF), the camera pose can be efficiently estimated by directly minimizing the error of the depth images on the ...

Bylow, Erik; Sturm, Ju?rgen; Kerl, Christian; Kahl, Fredrik; Cremers, Daniel

2013-01-01

149

INTERACTIVE PARAMETRIC MODELLING. POG a tool the cultural heritage monument 3D reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Historic monument and archaeological site 3D reconstruction is nowadays often required for many applications (scientific and architectural studies, virtual visits for a better understanding of the monument, etc). This task is very time-consuming. Automating the modelling of the most common components could ease this 3D work and produce accurate, consistent and re-usable models. Based upon compound rules of architectural elements but also upon various other data sources such as photographs and...

Chevrier, Christine; Perrin, Jean-pierre

2008-01-01

150

Comparisons of CME morphological characteristics derived from five 3D reconstruction methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We compare different methods to reconstruct the three-dimensional (3D) CME morphology. The explored methods include geometric localisation, mask fitting, forward modeling, polarisation ratio and local correlation tracking plus triangulation. The five methods are applied to the same CME event, which occurred on August 7 2010. Their corresponding results are presented and compared, especially in their propagation direction and spatial extent in 3D. We find that mask fitting an...

Feng, Li; Inhester, Bernd; Marilena, Mierla

2012-01-01

151

Reconstructed 3D models of digestive organs of developing Atlantic cod (Gadus morhua) larvae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Six 3D models of the digestive system during ontogeny were reconstructed from histological sections of Atlantic cod larvae. The 3D models clearly visualize the following features: folding of the gut rotation; subdivision of digestive tract into foregut, midgut, and hindgut by sphincters; development of stomach and pyloric caeca from 39 dph; location of entrances of bile and pancreatic ducts in the medial plane of the anterior midgut; ontogeny of pancreas from a compact organ to an elongated a...

Kamisaka, Yuko; Rønnestad, Ivar

2010-01-01

152

Combining extraction and 3D reconstruction of vessel center lines in biplane subtraction angiography  

Science.gov (United States)

Segmentation and 3D reconstruction of vessel center lines from subtraction angiography is difficult because of noise, an uneven distribution of the contrast agent, and bone structures concealing the vessels. In biplane images, some ambiguities in segmentation in one of the images can be resolved using image information from the other image. Images are first processed separately. A-priori vessel probabilities are computed using the grey value in the image. Gradients and second derivatives are computed using gaussian derivatives. Subsequently, 3D reconstruction is carried out in a line-by-line fashion between user-specified base lines on both images. The user is asked to point out corresponding vessel cross-sections on the frontal and lateral image. 3D locations are computed. Between adjacent 3D locations, intermediate 3D locations are estimated iteratively using location, curvature and size of the previously computed 3D vessel cross-section. The estimates are optimized evaluating local attributes in the two projection images, such as the grey level, the gradient and the closeness to the initial estimate. WE applied the method for the reconstruction of artificial and real structures. The artificial object consisted of metal wires with sizes ranging between 1 and 5 mm. Various parts of the structure were extracted and reconstructed successfully. Reconstructing center lines from real images was more difficult because of the image degrading influences. Structures with a size of about 1 mm were extracted and reconstructed successfully even though they were barely visible. The amount of user interaction depended on the visibility of the structures in the two images.

Toennies, Klaus D.; Remonda, Luca; Koster, David

1998-06-01

153

Full 3-D cluster-based iterative image reconstruction tool for a small animal PET camera  

Energy Technology Data Exchange (ETDEWEB)

Iterative reconstruction methods are commonly used to obtain images with high resolution and good signal-to-noise ratio in nuclear imaging. The aim of this work was to develop a scalable, fast, cluster based, fully 3-D iterative image reconstruction package for our small animal PET camera, the miniPET. The reconstruction package is developed to determine the 3-D radioactivity distribution from list mode type of data sets and it can also simulate noise-free projections of digital phantoms. We separated the system matrix generation and the fully 3-D iterative reconstruction process. As the detector geometry is fixed for a given camera, the system matrix describing this geometry is calculated only once and used for every image reconstruction, making the process much faster. The Poisson and the random noise sensitivity of the ML-EM iterative algorithm were studied for our small animal PET system with the help of the simulation and reconstruction tool. The reconstruction tool has also been tested with data collected by the miniPET from a line and a cylinder shaped phantom and also a rat.

Valastyan, I. [Royal Institute of Technology, Stockholm (Sweden) and Institute of Nuclear Research of the Hungarian Academy of Sciences, H 4026 Debrecen (Hungary)]. E-mail: vivan@atomki.hu; Imrek, J. [Institute of Nuclear Research of the Hungarian Academy of Sciences, H 4026 Debrecen (Hungary); Molnar, J. [Institute of Nuclear Research of the Hungarian Academy of Sciences, H 4026 Debrecen (Hungary); Novak, D. [Institute of Nuclear Research of the Hungarian Academy of Sciences, H 4026 Debrecen (Hungary); Balkay, L. [PET Center, University of Debrecen, Debrecen (Hungary); Emri, M. [PET Center, University of Debrecen, Debrecen (Hungary); Tron, L. [PET Center, University of Debrecen, Debrecen (Hungary); Buekki, T. [MEDISO Ltd., Budapest (Hungary); Kerek, A. [Royal Institute of Technology, Stockholm (Sweden)

2007-02-01

154

Full 3-D cluster-based iterative image reconstruction tool for a small animal PET camera  

International Nuclear Information System (INIS)

Iterative reconstruction methods are commonly used to obtain images with high resolution and good signal-to-noise ratio in nuclear imaging. The aim of this work was to develop a scalable, fast, cluster based, fully 3-D iterative image reconstruction package for our small animal PET camera, the miniPET. The reconstruction package is developed to determine the 3-D radioactivity distribution from list mode type of data sets and it can also simulate noise-free projections of digital phantoms. We separated the system matrix generation and the fully 3-D iterative reconstruction process. As the detector geometry is fixed for a given camera, the system matrix describing this geometry is calculated only once and used for every image reconstruction, making the process much faster. The Poisson and the random noise sensitivity of the ML-EM iterative algorithm were studied for our small animal PET system with the help of the simulation and reconstruction tool. The reconstruction tool has also been tested with data collected by the miniPET from a line and a cylinder shaped phantom and also a rat

2007-02-01

155

GPU-based 3D cone-beam CT image reconstruction for large data volume.  

Science.gov (United States)

Currently, 3D cone-beam CT image reconstruction speed is still a severe limitation for clinical application. The computational power of modern graphics processing units (GPUs) has been harnessed to provide impressive acceleration of 3D volume image reconstruction. For extra large data volume exceeding the physical graphic memory of GPU, a straightforward compromise is to divide data volume into blocks. Different from the conventional Octree partition method, a new partition scheme is proposed in this paper. This method divides both projection data and reconstructed image volume into subsets according to geometric symmetries in circular cone-beam projection layout, and a fast reconstruction for large data volume can be implemented by packing the subsets of projection data into the RGBA channels of GPU, performing the reconstruction chunk by chunk and combining the individual results in the end. The method is evaluated by reconstructing 3D images from computer-simulation data and real micro-CT data. Our results indicate that the GPU implementation can maintain original precision and speed up the reconstruction process by 110-120 times for circular cone-beam scan, as compared to traditional CPU implementation. PMID:19730744

Zhao, Xing; Hu, Jing-Jing; Zhang, Peng

2009-01-01

156

3D Reconstruction and Restoration Monitoring of Sculptural Artworks by a Multi-Sensor Framework  

Directory of Open Access Journals (Sweden)

Full Text Available Nowadays, optical sensors are used to digitize sculptural artworks by exploiting various contactless technologies. Cultural Heritage applications may concern 3D reconstructions of sculptural shapes distinguished by small details distributed over large surfaces. These applications require robust multi-view procedures based on aligning several high resolution 3D measurements. In this paper, the integration of a 3D structured light scanner and a stereo photogrammetric sensor is proposed with the aim of reliably reconstructing large free form artworks. The structured light scanner provides high resolution range maps captured from different views. The stereo photogrammetric sensor measures the spatial location of each view by tracking a marker frame integral to the optical scanner. This procedure allows the computation of the rotation-translation matrix to transpose the range maps from local view coordinate systems to a unique global reference system defined by the stereo photogrammetric sensor. The artwork reconstructions can be further augmented by referring metadata related to restoration processes. In this paper, a methodology has been developed to map metadata to 3D models by capturing spatial references using a passive stereo-photogrammetric sensor. The multi-sensor framework has been experienced through the 3D reconstruction of a Statue of Hope located at the English Cemetery in Florence. This sculptural artwork has been a severe test due to the non-cooperative environment and the complex shape features distributed over a large surface.

Sandro Barone

2012-12-01

157

Fast 3D iterative image reconstruction for SPECT with rotating slat collimators  

International Nuclear Information System (INIS)

As an alternative to the use of traditional parallel hole collimators, SPECT imaging can be performed using rotating slat collimators. While maintaining the spatial resolution, a gain in image quality could be expected from the higher photon collection efficiency of this type of collimator. However, the use of iterative methods to do fully three-dimensional (3D) reconstruction is computationally much more expensive and furthermore involves slow convergence compared to a classical SPECT reconstruction. It has been proposed to do 3D reconstruction by splitting the system matrix into two separate matrices, forcing the reconstruction to first estimate the sinograms from the rotating slat SPECT data before estimating the image. While alleviating the computational load by one order of magnitude, this split matrix approach would result in fast computation of the projections in an iterative algorithm, but does not solve the problem of slow convergence. There is thus a need for an algorithm which speeds up convergence while maintaining image quality for rotating slat collimated SPECT cameras. Therefore, we developed a reconstruction algorithm based on the split matrix approach which allows both a fast calculation of the forward and backward projection and a fast convergence. In this work, an algorithm of the maximum likelihood expectation maximization (MLEM) type, obtained from a split system matrix MLEM reconstruction, is proposed as a reconstruction method for rotating slat collimated SPECT data. Here, we compare this new algorithm to the conventional split system matrix MLEM method and to a gold standard fully 3D MLEM reconstruction algorithm on the basis of computational load, convergence and contrast-to-noise. Furthermore, ordered subsets expectation maximization (OSEM) implementations of these three algorithms are compared. Calculation of computational load and convergence for the different algorithms shows a speedup for the new method of 38 and 426 compared to the split matrix MLEM approach and the fully 3D MLEM respectively and a speedup of 16 and 21 compared to the split matrix OSEM and the fully 3D OSEM respectively. A contrast-to-noise study based on simulated data shows that our new approach has comparable accuracy as the fully 3D reconstruction method. The algorithm developed in this study allows iterative image reconstruction of rotating slat collimated SPECT data with equal image quality in a comparable amount of computation time as a classical SPECT reconstruction.

2009-02-07

158

Alignment, segmentation and 3-D reconstruction of serial sections based on automated algorithm  

Science.gov (United States)

A well-defined three-dimensional (3-D) reconstruction of bone-cartilage transitional structures is crucial for the osteochondral restoration. This paper presents an accurate, computationally efficient and fully-automated algorithm for the alignment and segmentation of two-dimensional (2-D) serial to construct the 3-D model of bone-cartilage transitional structures. Entire system includes the following five components: (1) image harvest, (2) image registration, (3) image segmentation, (4) 3-D reconstruction and visualization, and (5) evaluation. A computer program was developed in the environment of Matlab for the automatic alignment and segmentation of serial sections. Automatic alignment algorithm based on the position's cross-correlation of the anatomical characteristic feature points of two sequential sections. A method combining an automatic segmentation and an image threshold processing was applied to capture the regions and structures of interest. SEM micrograph and 3-D model reconstructed directly in digital microscope were used to evaluate the reliability and accuracy of this strategy. The morphology of 3-D model constructed by serial sections is consistent with the results of SEM micrograph and 3-D model of digital microscope.

Bian, Weiguo; Tang, Shaojie; Xu, Qiong; Lian, Qin; Wang, Jin; Li, Dichen

2012-12-01

159

A parallel implementation of 3-d CT image reconstruction on a hypercube multiprocessor  

International Nuclear Information System (INIS)

In this paper, the authors describe how image reconstruction in computerized tomography (CT) can be parallelized on a message-passing multiprocessor. In particular, the results obtained from parallel implementation of 3-D CT image reconstruction for parallel beam geometries on the Intel hypercube, iPSC/2, are presented. A two stage pipelining approach is employed for filtering (convolution) and backprojection. The conventional sequential convolution algorithm is modified such that the symmetry of the filter kernel is fully utilized for parallelization. In the backprojection stage, the 3-D incremental algorithm, the authors' recently developed backprojection scheme which is shown to be faster than conventional algorithm, is parallelized

1990-06-01

160

On the use of Orientation Filters for 3D Reconstruction in Event-Driven Stereo Vision  

Directory of Open Access Journals (Sweden)

Full Text Available The recently developed Dynamic Vision Sensors (DVS sense visual information asynchronously and code it into trains of events with sub-micro second temporal resolution. This high temporal precision makes the output of these sensors especially suited for dynamic 3D visual reconstruction, by matching corresponding events generated by two different sensors in a stereo setup. This paper explores the use of Gabor filters to extract information about the orientation of the object edges that produce the events, therefore increasing the number of restrictions applied to the matching algorithm. This strategy provides a larger number of pairs of matching events, improving the final 3D reconstruction.

Luis AlejandroCamunas-Mesa

2014-03-01

 
 
 
 
161

On the use of orientation filters for 3D reconstruction in event-driven stereo vision.  

Science.gov (United States)

The recently developed Dynamic Vision Sensors (DVS) sense visual information asynchronously and code it into trains of events with sub-micro second temporal resolution. This high temporal precision makes the output of these sensors especially suited for dynamic 3D visual reconstruction, by matching corresponding events generated by two different sensors in a stereo setup. This paper explores the use of Gabor filters to extract information about the orientation of the object edges that produce the events, therefore increasing the number of constraints applied to the matching algorithm. This strategy provides more reliably matched pairs of events, improving the final 3D reconstruction. PMID:24744694

Camuñas-Mesa, Luis A; Serrano-Gotarredona, Teresa; Ieng, Sio H; Benosman, Ryad B; Linares-Barranco, Bernabe

2014-01-01

162

Grammar-based Automatic 3D Model Reconstruction from Terrestrial Laser Scanning Data  

Science.gov (United States)

The automatic reconstruction of 3D buildings has been an important research topic during the last years. In this paper, a novel method is proposed to automatically reconstruct the 3D building models from segmented data based on pre-defined formal grammar and rules. Such segmented data can be extracted e.g. from terrestrial or mobile laser scanning devices. Two steps are considered in detail. The first step is to transform the segmented data into 3D shapes, for instance using the DXF (Drawing Exchange Format) format which is a CAD data file format used for data interchange between AutoCAD and other program. Second, we develop a formal grammar to describe the building model structure and integrate the pre-defined grammars into the reconstruction process. Depending on the different segmented data, the selected grammar and rules are applied to drive the reconstruction process in an automatic manner. Compared with other existing approaches, our proposed method allows the model reconstruction directly from 3D shapes and takes the whole building into account.

Yu, Q.; Helmholz, P.; Belton, D.; West, G.

2014-04-01

163

Clinical application of 3D reconstruction of tracheobronchial tree with electron beam CT  

International Nuclear Information System (INIS)

Objective: To explore the clinical promise of CT 3D reconstruction of tracheobronchial tree (TBT) by analyzing 73 cases retrospectively. Methods: All the 73 cases were collected from October 1997 to February 2000, who were scanned by EBCT with 130 kV and 630 mA. The scanning method was continuous volume scan, the slice thickness were 3 mm or 1.5 mm. All cross-sectional images were transmitted to the INSIGHT workstation and reconstructed with SSD (shaded surface display), and the threshold setting were -500 to -300 HU. Results: 3D reconstruction of TBT with EBCT could reveal the abnormal changes of TBT by many kinds of diseases including central cancer, inflammation, bronchiectasis, saber-sheath trachea, trachea cancer, congenital disorders, post-surgical changes of lung cancer, and stenoses by adjacent benign or malignant diseases. It could be used to locate the stenoses and measure stenotic extent. Of the 35 central cancer cases with 3D reconstruction, 6 cases were pestle obstructed, 15 cases cone obstructed, 5 cases interrupted irregularly, 8 cases with eccentric stenoses, and 1 case with right stem destroyed and right upper lobe bronchus obstructed. Conclusion: 3D reconstruction of TBT has characteristic sign in the diagnosis or differential diagnosis of central airway's benign or malignant stenoses, and it is of instructional value in clinical use

2002-02-01

164

3D noise power spectrum applied on clinical MDCT scanners: effects of reconstruction algorithms and reconstruction filters  

Science.gov (United States)

The noise power spectrum (NPS) is the reference metric for understanding the noise content in computed tomography (CT) images. To evaluate the noise properties of clinical multidetector (MDCT) scanners, local 2D and 3D NPSs were computed for different acquisition reconstruction parameters. A 64- and a 128-MDCT scanners were employed. Measurements were performed on a water phantom in axial and helical acquisition modes. CT dose index was identical for both installations. Influence of parameters such as the pitch, the reconstruction filter (soft, standard and bone) and the reconstruction algorithm (filtered-back projection (FBP), adaptive statistical iterative reconstruction (ASIR)) were investigated. Images were also reconstructed in the coronal plane using a reformat process. Then 2D and 3D NPS methods were computed. In axial acquisition mode, the 2D axial NPS showed an important magnitude variation as a function of the z-direction when measured at the phantom center. In helical mode, a directional dependency with lobular shape was observed while the magnitude of the NPS was kept constant. Important effects of the reconstruction filter, pitch and reconstruction algorithm were observed on 3D NPS results for both MDCTs. With ASIR, a reduction of the NPS magnitude and a shift of the NPS peak to the low frequency range were visible. 2D coronal NPS obtained from the reformat images was impacted by the interpolation when compared to 2D coronal NPS obtained from 3D measurements. The noise properties of volume measured in last generation MDCTs was studied using local 3D NPS metric. However, impact of the non-stationarity noise effect may need further investigations.

Miéville, Frédéric A.; Bolard, Gregory; Benkreira, Mohamed; Ayestaran, Paul; Gudinchet, François; Bochud, François; Verdun, Francis R.

2011-03-01

165

Research of Texture Extraction and Mapping based on 3D Building Reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes texture extraction and mapping methods from image of 3D building, 3D building in image can be reconstructed based on plane, through the correct input image?We propose a new method to eliminate distorted Distortion, in order to correct the texture image and estimate textures color by compensating for light color. This method avoids the middle of the process of 3D measurement. We proposed a texture mapping strategy based surface particle, a better solution to the shooting-re...

Chen Xiaogang; Zhou Zhuoyun

2012-01-01

166

Use of enhancement algorithm to suppress reflections in 3-D reconstructed capsule endoscopy images  

Directory of Open Access Journals (Sweden)

Full Text Available In capsule endoscopy (CE, there is research to develop hardware that enables ‘‘real’’ three-dimensional (3-D video. However, it should not be forgotten that ‘‘true’’ 3-D requires dual video images. Inclusion of two cameras within the shell of a capsule endoscope though might be unwieldy at present. Therefore, in an attempt to approximate a 3-D reconstruction of the digestive tract surface, a software that recovers information-using gradual variation of shading-from monocular two-dimensional CE images has been proposed. Light reflections on the surface of the digestive tract are still a significant problem. Therefore, a phantom model and simulator has been constructed in an attempt to check the validity of a highlight suppression algorithm. Our results confirm that 3-D representation software performs better with simultaneous application of a highlight reduction algorithm. Furthermore, 3-D representation follows a good approximation of the real distance to the lumen surface.

Anastasios Koulaouzidis

2013-01-01

167

APPLICATION OF A SPATIALLY VARIANT SYSTEM MODEL FOR 3-D WHOLE-BODY PET IMAGE RECONSTRUCTION  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Accurate system modeling in tomographic image reconstruction has been shown to reduce the spatial variance of resolution and improve quantitative accuracy. System modeling can be improved through analytic calculations, Monte Carlo simulations, and physical measurements. This work presents a novel measured system model and incorporates this model into a fully 3-D statistical reconstruction method. Empirical testing of the resolution versus noise benefits reveal a modest improvement in spatial ...

Alessio, Adam M.; Kinahan, Paul E.

2008-01-01

168

3D RECONSTRUCTION AND ANALYSIS OF THE FRAGMENTED GRAINS IN A COMPOSITE MATERIAL  

Digital Repository Infrastructure Vision for European Research (DRIVER)

X-ray microtomography from solid propellant allows studying the microstructure of fragmented grains in damaged samples. A new reconstruction algorithm of fragmented grains for 3D images is introduced. Based on a watershed transform of a morphological closing of the input image, the algorithm can be used  with different sets of markers. Two of them are compared. After the grain reconstruction, a multiscale segmentation  algorithm is used to extract each fragment of the damaged grains. T...

Luc Gillibert; Dominique Jeulin

2013-01-01

169

Integration of knowledge to support automatic object reconstruction from images and 3D data  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Object reconstruction is an important task in many fields of application as it allows to generate digital representations of our physical world used as base for analysis, planning, construction, visualization or other aims. A reconstruction itself normally is based on reliable data (images, 3D point clouds for example) expressing the object in his complete extent. This data then has to be compiled and analyzed in order to extract all necessary geometrical elements, which represent the object ...

Boochs, Frank; Marbs, Andreas; Truong, Hung; Ben Hmida, Helmi; Karmacharya, Ashish; Cruz, Christophe; Habed, Adlane; Voisin, Yvon; Nicolle, Christophe

2011-01-01

170

3D scene reconstruction by integration of photometric and geometric methods  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis, we have developed a framework for image-based 3D reconstruction of sparse point clouds and dense depth maps. The framework is based on self-consistent integration of geometric and photometric constraints on the surface shape, such as triangulation, defocus and reflectance. The reconstruction of point clouds starts by tracking object features over a range of distances from the camera with a small depth of field, leading to a varying degree of defocus for each feature.

D Angelo, Pablo

2007-01-01

171

Optimal noise reduction in 3D reconstructions of single particles using a volume-normalized filter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The high noise level found in single-particle electron cryo-microscopy (cryo-EM) image data presents a special challenge for three-dimensional (3D) reconstruction of the imaged molecules. The spectral signal-to-noise ratio (SSNR) and related Fourier shell correlation (FSC) functions are commonly used to assess and mitigate the noise-generated error in the reconstruction. Calculation of the SSNR and FSC usually includes the noise in the solvent region surrounding the particle and therefore doe...

Sindelar, Charles V.; Grigorieff, Nikolaus

2012-01-01

172

The role of 3D Helical CT in the reconstructive treatment of maxillofacial cancers  

International Nuclear Information System (INIS)

Purpose of this work is to investigate the role of Helical CT and the usefulness of three-dimensional (3D) imaging for pre-operative planning and follow-up of reconstructive maxillofacial surgery with alloplastic material in neoplastic disease involving this region. From 1996 to 1999 eleven patients were examined with Helical CT and 3D images for planning of maxillofacial plastic and reconstructive surgery for advanced cancer of this anatomically complex region. A 3D-modulated titanium mesh (100%) or micro nets was used to rebuild the anterior surface of maxillary bone and the orbital floor. The mesh was cut to the appropriate size and shape and curved where necessary. Within the residual sinusal cavity a siliconed filling was used surmounting an acrylic prosthesis with dental arch to rebuild the palate. A rehydrated bovine pericardium was affixed and moduled on the borders in two cases only. Three-dimensionally reconstructed CT images were obtained preoperatively and at least 6 months postoperatively in all patients. The images were generated on a computer workstation using the shaded surface display (SSD) software with threshold values ranging 425 to 630 HU, and a more closed window for the imaging of titanium mesh/bone interface in the post surgical follow-up. It was obtained an excellent complete spatial depiction of maxillo facial region both before and after surgery, with no artefacts so important as to affect the 3D reconstruction process and the image quality. Together with the head-neck surgical team it could be worked for preoperative planning through CT scans by different 3D points of view. The 3D reconstructed follow-up scans showed good filling of the defect in the area where the titanium mesh had been used. Then efficacious bone modelling and good biocompatibility of the alloplastic material were seen in all patients, with no inflammatory reactions. Titanium is a well-known material, which is widely used for cranioplasty. It is a radiolucent, non-ferrous metal of low atomic number that allows very clear CT and MR images to be obtained. Further Ti features are strength, biocompatibility and easy handling. 3D Helical CT scan has proven to be the most complete and accurate imaging technique for reconstructive plastic surgery with alloplastic material in advanced maxillofacial cancer, also considering the anatomic and functional complexity of his area. The prospect is provided to identify virtual 3D presurgical ablation planes. These may allow the surgeon to improve plastic reconstruction and shorten intervention time

2000-12-01

173

Error Evaluation in a Stereovision-Based 3D Reconstruction System  

Directory of Open Access Journals (Sweden)

Full Text Available The work presented in this paper deals with the performance analysis of the whole 3D reconstruction process of imaged objects, specifically of the set of geometric primitives describing their outline and extracted from a pair of images knowing their associated camera models. The proposed analysis focuses on error estimation for the edge detection process, the starting step for the whole reconstruction procedure. The fitting parameters describing the geometric features composing the workpiece to be evaluated are used as quality measures to determine error bounds and finally to estimate the edge detection errors. These error estimates are then propagated up to the final 3D reconstruction step. The suggested error analysis procedure for stereovision-based reconstruction tasks further allows evaluating the quality of the 3D reconstruction. The resulting final error estimates enable lastly to state if the reconstruction results fulfill a priori defined criteria, for example, fulfill dimensional constraints including tolerance information, for vision-based quality control applications for example.

Kohler Sophie

2010-01-01

174

Evaluation of iterative sparse object reconstruction from few projections for 3-D rotational coronary angiography.  

Science.gov (United States)

A 3-D reconstruction of the coronary arteries offers great advantages in the diagnosis and treatment of cardiovascular disease, compared to 2-D X-ray angiograms. Besides improved roadmapping, quantitative vessel analysis is possible. Due to the heart's motion, rotational coronary angiography typically provides only 5-10 projections for the reconstruction of each cardiac phase, which leads to a strongly undersampled reconstruction problem. Such an ill-posed problem can be approached with regularized iterative methods. The coronary arteries cover only a small fraction of the reconstruction volume. Therefore, the minimization of the mbiL(1) norm of the reconstructed image, favoring spatially sparse images, is a suitable regularization. Additional problems are overlaid background structures and projection truncation, which can be alleviated by background reduction using a morphological top-hat filter. This paper quantitatively evaluates image reconstruction based on these ideas on software phantom data, in terms of reconstructed absorption coefficients and vessel radii. Results for different algorithms and different input data sets are compared. First results for electrocardiogram-gated reconstruction from clinical catheter-based rotational X-ray coronary angiography are presented. Excellent 3-D image quality can be achieved. PMID:18955171

Hansis, Eberhard; Schäfer, Dirk; Dössel, Olaf; Grass, Michael

2008-11-01

175

Some remarks concerning the influence of electron noise on 3D reconstruction  

International Nuclear Information System (INIS)

In a recent review Saxton has criticized our statement that a '3D reconstuction requires the same integral dose as a conventional 2D micrograph provided the level of significance and the resolution are identical' which has been deduced in a paper on election noise in 3D reconstruction. He states that this clain has been the subject of 'considerable discussion and confusion' and deduces from signal-to-noise considerations that this equivalence' is not borne out'. On the other hand, however, he agrees with our mathematical theory. The differences between Saxton and ourselves arise because he does not use our definition of significance. The comparison between the results of a 3D and a 2D analysis requires that the information delivered from both methods is of the same kind. There is not much sense in comparing directly the density of a 3D reconstruction with that of a projection because they are physically different. If, however, the information is concerned with structure features recognizable from a 3D reconstruction as well as from a projection, the comparison can be made. (orig.)

1981-01-01

176

High speed stereoscopic shadowgraph imaging and its digital 3D reconstruction  

International Nuclear Information System (INIS)

A stereoscopic shadowgraph system has been developed based on the conventional z-type schlieren configuration. The test volume is set at the intersection of two inclined converging beams formed by two pairs of parabolic mirrors. Two synchronized high speed cameras are applied to record the shadowgraph image pairs simultaneously. A precisely etched metal mesh plate is used to calibrate the stereoscopic shadowgraph system. By combining the calibration parameters and coordinates of the matching points in stereo images, the depth information and the 3D view of the shadowgraph images are obtained. A crystal block with internal 3D images created by laser etching is used as a model for static object reconstruction and validation. The 3D coordinates obtained by the digital 3D reconstruction are in good agreement with the real dimensions. The developed stereoscopic technique is then applied to investigate the bursting dynamics of a bubble. The time resolved bubble-bursting process has been reconstructed successfully. The quantitative velocity measurement reveals that the bubble collapses at a constant velocity of around 7 m s?1, which corresponds to a high Weber number. As a result, finger-like structures are observable around the rim of the collapsing bubble. The stereoscopic shadowgraph technique has been shown to be effective for 3D visualization and quantitative measurement

2011-06-01

177

Reconstructing photorealistic 3D models from image sequence using domain decomposition method  

Science.gov (United States)

In the fields of industrial design, artistic design and heritage conservation, physical objects are usually digitalized by reverse engineering through some 3D scanning methods. Structured light and photogrammetry are two main methods to acquire 3D information, and both are expensive. Even if these expensive instruments are used, photorealistic 3D models are seldom available. In this paper, a new method to reconstruction photorealistic 3D models using a single camera is proposed. A square plate glued with coded marks is used to place the objects, and a sequence of about 20 images is taken. From the coded marks, the images are calibrated, and a snake algorithm is used to segment object from the background. A rough 3d model is obtained using shape from silhouettes algorithm. The silhouettes are decomposed into a combination of convex curves, which are used to partition the rough 3d model into some convex mesh patches. For each patch, the multi-view photo consistency constraints and smooth regulations are expressed as a finite element formulation, which can be resolved locally, and the information can be exchanged along the patches boundaries. The rough model is deformed into a fine 3d model through such a domain decomposition finite element method. The textures are assigned to each element mesh, and a photorealistic 3D model is got finally. A toy pig is used to verify the algorithm, and the result is exciting.

Xiong, Hanwei; Pan, Ming; Zhang, Xiangwei

2009-11-01

178

Applicability of 3D-CT facial reconstruction for forensic individual identification Aplicabilidade da reconstrução facial em 3D-TC para identificação individual forense  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering techni...

2003-01-01

179

Estimation of 3D reconstruction errors in a stereo-vision system  

Science.gov (United States)

The paper presents an approach for error estimation for the various steps of an automated 3D vision-based reconstruction procedure of manufactured workpieces. The process is based on a priori planning of the task and built around a cognitive intelligent sensory system using so-called Situation Graph Trees (SGT) as a planning tool. Such an automated quality control system requires the coordination of a set of complex processes performing sequentially data acquisition, its quantitative evaluation and the comparison with a reference model (e.g., CAD object model) in order to evaluate quantitatively the object. To ensure efficient quality control, the aim is to be able to state if reconstruction results fulfill tolerance rules or not. Thus, the goal is to evaluate independently the error for each step of the stereo-vision based 3D reconstruction (e.g., for calibration, contour segmentation, matching and reconstruction) and then to estimate the error for the whole system. In this contribution, we analyze particularly the segmentation error due to localization errors for extracted edge points supposed to belong to lines and curves composing the outline of the workpiece under evaluation. The fitting parameters describing these geometric features are used as quality measure to determine confidence intervals and finally to estimate the segmentation errors. These errors are then propagated through the whole reconstruction procedure, enabling to evaluate their effect on the final 3D reconstruction result, specifically on position uncertainties. Lastly, analysis of these error estimates enables to evaluate the quality of the 3D reconstruction, as illustrated by the shown experimental results.

Belhaoua, A.; Kohler, S.; Hirsch, E.

2009-06-01

180

A Novel Image Compression Algorithm for High Resolution 3D Reconstruction  

Science.gov (United States)

This research presents a novel algorithm to compress high-resolution images for accurate structured light 3D reconstruction. Structured light images contain a pattern of light and shadows projected on the surface of the object, which are captured by the sensor at very high resolutions. Our algorithm is concerned with compressing such images to a high degree with minimum loss without adversely affecting 3D reconstruction. The Compression Algorithm starts with a single level discrete wavelet transform (DWT) for decomposing an image into four sub-bands. The sub-band LL is transformed by DCT yielding a DC-matrix and an AC-matrix. The Minimize-Matrix-Size Algorithm is used to compress the AC-matrix while a DWT is applied again to the DC-matrix resulting in LL2, HL2, LH2 and HH2 sub-bands. The LL2 sub-band is transformed by DCT, while the Minimize-Matrix-Size Algorithm is applied to the other sub-bands. The proposed algorithm has been tested with images of different sizes within a 3D reconstruction scenario. The algorithm is demonstrated to be more effective than JPEG2000 and JPEG concerning higher compression rates with equivalent perceived quality and the ability to more accurately reconstruct the 3D models.

Siddeq, M. M.; Rodrigues, M. A.

2014-06-01

 
 
 
 
181

A Smartphone Interface for a Wireless EEG Headset with Real-Time 3D Reconstruction  

DEFF Research Database (Denmark)

We demonstrate a fully functional handheld brain scanner consisting of a low-cost 14-channel EEG headset with a wireless connec- tion to a smartphone, enabling minimally invasive EEG monitoring in naturalistic settings. The smartphone provides a touch-based interface with real-time brain state decoding and 3D reconstruction.

Stopczynski, Arkadiusz; Larsen, Jakob Eg

2011-01-01

182

Design of the discrete skew geometry and iterative reconstruction of the MV3D scanner  

International Nuclear Information System (INIS)

Design considerations for airport security volumetric imaging scanners differ significantly from those for medical CT scanners, despite the much they have in common. We describe what drives these differences, then describe how we account for these considerations with a combination of an innovative 'discrete skew' geometry and iterative reconstruction in the new L-3 MV3D security scanner product. (orig.)

2011-07-11

183

3D Reconstruction of Cultural Values at the Regional History Museum-Veliko Tarnovo  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The project paper presents the work done by the Regional History Museum – Veliko Tarnovo (RHM) on 3D reconstruction of cultural values and objects from the Veliko Tarnovo region – the St Peter and St Paul church in Veliko Tarnovo, the chorus of the metropolitan Nativity church in Arbanassi and the St. Dimitar church in Arbanassi.

Sabev, Plamen

2012-01-01

184

Transnasal Skull Base Reconstruction Using a 3-D Endoscope: Our First Impressions*  

Science.gov (United States)

Nowadays endoscopic skull base reconstruction is safely and effectively performed by means of two-dimensional (2-D) endoscopic technique. The aim of our study is to compare our 2-D experience with the novel 3-D technology in the field of skull base reconstruction techniques. In this study four patients treated with various kinds of planned duraplasty are included. The new 3-D technology was compared with the high-definition 2-D scopes during the different steps of the procedures. The 3-D endoscopic skull base reconstruction obtained primary closure without complications in all cases. According to the subjective opinion of experienced endosurgeons, this novel technique improved depth perception, distance and size estimation, ability to identify specific anatomic structures, and hand–eye coordination. The main drawbacks detected were inferior sharpness, contrast and lighting that impaired the application of the technique in narrow sinonasal spaces. According to our preliminary impressions, 3-D endoscopic skull base reconstruction is an effective and safe procedure and could represent a significant advantage for accurate managing of the skull base region.

Castelnuovo, Paolo; Battaglia, Paolo; Turri-Zanoni, Mario; Volpi, Luca; Bignami, Maurizio; Dallan, Iacopo

2012-01-01

185

3D tomographic reconstruction from 2D data using spherical harmonics  

International Nuclear Information System (INIS)

Tomographic reconstruction of a 3D object in terms of spherical harmonics from a smaller number of 2D data sets is shown to be possible in cases of objects of high symmetry and/or low shape anisotropy. A test case using an object of cubic symmetry shows that the reconstruction can work well in such high symmetry cases when only two or three data directions are available. Numerical tests suggest that reconstructions are best done from data taken in low symmetry directions

1987-01-01

186

Weighted backprojection approach to cone beam 3D projection reconstruction for truncated spherical detection geometry  

International Nuclear Information System (INIS)

A new analytical three-dimensional cone beam reconstruction algorithm is presented for truncated spherical detection geometry. The basic idea of the proposed algorithm is the formation of spatially invariant 3D blurred back-projected volumetric image by the use of the weighted backprojection of cone beam projection data and subsequent 3D filtering using an acceptance angle dependent ? filter. The backprojection weighting function is calculated on the basis of each given geometrical condition, i.e., detection geometry or degree of truncation, position of cone beam apex, and backprojection point. The proposed algorithm is derived analytically and is computationally efficient. Performance of the algorithm is evaluated by the reconstruction of 3D volumetric images using simulated data from arbitrarily truncated spherical detector geometries

1994-03-01

187

Experimental justification for using 3D conductivity reconstructions in electrical impedance tomography.  

Science.gov (United States)

Conductivity imaging of the breast using electrical impedance tomography (EIT) is a three-dimensional (3D) problem since the induced currents are free to travel through the entire tissue volume. It is therefore necessary to determine the effect this 3D current flow has on the image reconstruction problem and to ascertain how much benefit is gained by using a more appropriate 3D model to estimate the conductivity distribution. In addition, it is important to consider how much is gained if measurements are collected from multiple circular arrays of electrodes positioned around the breast as opposed to just a single plane of electrodes. We used a 64 electrode EIT system to collect data from a series of high contrast saline phantoms to determine the benefits gained by using a 3D model and the incorporation of out-of-plane measurements. We found that it is preferable to use a 3D mesh even when looking only at a single plane through the object of interest and that this 3D mesh should extend in the axial direction at least one radius away from the plane of interest. Further, out-of-plane measurements enhance axial information and improve the quantification of reconstructed inclusions by a factor of 2.2 in the particular case presented here. These findings should ultimately be incorporated to clinical imaging with EIT when circular electrode arrays are employed. PMID:17664629

Halter, Ryan J; Hartov, Alex; Paulsen, Keith D

2007-07-01

188

Non-periodic 3-D motion estimation and reconstruction of coronary stents  

International Nuclear Information System (INIS)

C-arm CT enables 3-D imaging at high spatial resolution. Image quality would be sufficient for coronary artery stents at rest. However, spatial resolution is severely degraded by cardiac motion which needs to be considered in the reconstruction step. Existing approaches are based on detecting markers in the projection images. Based on the exact marker locations in all images, motion estimation and compensation is performed in the 2-D projection image domain and thus no 3-D motion information of the stent is available. In this paper a novel method for computing the non-periodic location of the stent markers in 3-D is proposed. The motion estimation step comprises marker detection in 2-D, computation of periodic 3-D motion and computation of non-periodic 3-D motion. For motion compensation the 3- D marker positions are used to compute an affine motion model as input for a motion compensated FDK reconstruction algorithm. First clinical results suggest a high image quality and the possibility to compute physiological parameters e.g. velocity curves. (orig.)

2011-07-11

189

Computer-aided detection of masses in digital tomosynthesis mammography: Comparison of three approaches  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The authors are developing a computer-aided detection (CAD) system for masses on digital breast tomosynthesis mammograms (DBT). Three approaches were evaluated in this study. In the first approach, mass candidate identification and feature analysis are performed in the reconstructed three-dimensional (3D) DBT volume. A mass likelihood score is estimated for each mass candidate using a linear discriminant analysis (LDA) classifier. Mass detection is determined by a decision threshold applied t...

Chan, Heang-ping; Wei, Jun; Zhang, Yiheng; Helvie, Mark A.; Moore, Richard H.; Sahiner, Berkman; Hadjiiski, Lubomir; Kopans, Daniel B.

2008-01-01

190

The effect of angular dose distribution on the detection of microcalcifications in digital breast tomosynthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: Substantial effort has been devoted to the clinical development of digital breast tomosynthesis (DBT). DBT is a three-dimensional (3D) x-ray imaging modality that reconstructs a number of thin image slices parallel to a stationary detector plane. Preliminary clinical studies have shown that the removal of overlapping breast tissue reduces image clutter and increases detectability of large, low contrast lesions. However, some studies, as well as anecdotal evidence, suggested decreased...

2011-01-01

191

A fast compressed sensing approach to 3D MR image reconstruction.  

Science.gov (United States)

The problem of high-resolution image volume reconstruction from reduced frequency acquisition sequences has drawn significant attention from the scientific community because of its practical importance in medical diagnosis. To address this issue, several reconstruction strategies have been recently proposed, which aim to recover the missing information either by exploiting the spatio-temporal correlations of the image series, or by imposing suitable constraints on the reconstructed image volume. The main contribution of this paper is to combine both these strategies in a compressed sensing framework by exploiting the gradient sparsity of the image volume. The resulting constrained 3D minimization problem is then solved using a penalized forward-backward splitting approach that leads to a convergent iterative two-step procedure. In the first step, the updating rule accords with the sequential nature of the data acquisitions, in the second step a truly 3D filtering strategy exploits the spatio-temporal correlations of the image sequences. The resulting NFCS-3D algorithm is very general and suitable for several kinds of medical image reconstruction problems. Moreover, it is fast, stable and yields very good reconstructions, even in the case of highly undersampled image sequences. The results of several numerical experiments highlight the optimal performance of the proposed algorithm and confirm that it is competitive with state of the art algorithms. PMID:20729163

Montefusco, Laura B; Lazzaro, Damiana; Papi, Serena; Guerrini, Carla

2011-05-01

192

Internet2-based 3D PET image reconstruction using a PC cluster  

International Nuclear Information System (INIS)

We describe an approach to fast iterative reconstruction from fully three-dimensional (3D) PET data using a network of PentiumIII PCs configured as a Beowulf cluster. To facilitate the use of this system, we have developed a browser-based interface using Java. The system compresses PET data on the user's machine, sends these data over a network, and instructs the PC cluster to reconstruct the image. The cluster implements a parallelized version of our preconditioned conjugate gradient method for fully 3D MAP image reconstruction. We report on the speed-up factors using the Beowulf approach and the impacts of communication latencies in the local cluster network and the network connection between the user's machine and our PC cluster. (author)

2002-08-07

193

Ab initio high-resolution single-particle 3D reconstructions: the symmetry adapted functions way.  

Science.gov (United States)

A protocol to attain high-resolution single-particle reconstructions is presented. The protocol is the concatenation of two procedures: one to obtain an ab initio low-resolution reconstruction, the other to determine a fixed point of the consecutive applications of fast projection matching and 3D reconstruction. It is a reciprocal space formulation where the Fourier coefficients of the 3D scattering density are expressed in terms of symmetry adapted functions and the 2D particle images are represented by their Fourier-Bessel transforms. The new protocol shows advantages in terms of speed and accuracy when compared to other methods currently in use. We illustrate its performance as applied to high-resolution cryo-electron micrographs of rotavirus. PMID:20599509

Estrozi, Leandro F; Navaza, Jorge

2010-12-01

194

Mutual information as a measure of reconstruction quality in 3D dynamic lung EIT  

International Nuclear Information System (INIS)

We report on a pilot study with healthy subjects who had an MR scan in addition to EIT data acquired with the Manchester fEITER system. The MR images are used to inform the external shape of a 3D EIT reconstruction model of the thorax, and small changes in the boundary that occur during respiration are addressed by incorporating the sensitivity with respect to boundary shape into a robust reconstruction algorithm. A quantitative comparison of the image quality for different EIT reconstructions is achieved through calculation of their mutual information with a segmented MR image. A shape corrected reconstruction algorithm reduces boundary artefacts relative to a standard reconstruction, and has a greater mutual information of approximately 4% with the segmented MR image.

2013-04-18

195

AWE multi-axis radiographic facility: A review of 3D-reconstructions from limited data  

International Nuclear Information System (INIS)

This paper presents a 3D-reconstruction study carried out to address issues regarding the optimal number of radiographic views and their orientations in a new flash X-radiography facility. The results presented in this paper are taken from reconstructions with noiseless projection data simulated from a phantom. These idealized results have shown the relative improvements gained by adding additional views, as well as the impact of varying the view orientations and the effectiveness of various constraints to suppress reconstruction artefacts. It has been concluded that, given sufficient a priori knowledge to implement appropriate constraints, a limited number of views (as few as five in the new facility) can give reasonable reconstructions, and that the reconstruction is relatively insensitive to the view orientation

2001-05-29

196

Computer-aided detection of clustered microcalcifications in multiscale bilateral filtering regularized reconstructed digital breast tomosynthesis volume  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Develop a computer-aided detection (CADe) system for clustered microcalcifications in digital breast tomosynthesis (DBT) volume enhanced with multiscale bilateral filtering (MSBF) regularization. Methods: With Institutional Review Board approval and written informed consent, two-view DBT of 154 breasts, of which 116 had biopsy-proven microcalcification (MC) clusters and 38 were free of MCs, was imaged with a General Electric GEN2 prototype DBT system. The DBT volumes were reconstructed with MSBF-regularized simultaneous algebraic reconstruction technique (SART) that was designed to enhance MCs and reduce background noise while preserving the quality of other tissue structures. The contrast-to-noise ratio (CNR) of MCs was further improved with enhancement-modulated calcification response (EMCR) preprocessing, which combined multiscale Hessian response to enhance MCs by shape and bandpass filtering to remove the low-frequency structured background. MC candidates were then located in the EMCR volume using iterative thresholding and segmented by adaptive region growing. Two sets of potential MC objects, cluster centroid objects and MC seed objects, were generated and the CNR of each object was calculated. The number of candidates in each set was controlled based on the breast volume. Dynamic clustering around the centroid objects grouped the MC candidates to form clusters. Adaptive criteria were designed to reduce false positive (FP) clusters based on the size, CNR values and the number of MCs in the cluster, cluster shape, and cluster based maximum intensity projection. Free-response receiver operating characteristic (FROC) and jackknife alternative FROC (JAFROC) analyses were used to assess the performance and compare with that of a previous study. Results: Unpaired two-tailedt-test showed a significant increase (p < 0.0001) in the ratio of CNRs for MCs with and without MSBF regularization compared to similar ratios for FPs. For view-based detection, a sensitivity of 85% was achieved at an FP rate of 2.16 per DBT volume. For case-based detection, a sensitivity of 85% was achieved at an FP rate of 0.85 per DBT volume. JAFROC analysis showed a significant improvement in the performance of the current CADe system compared to that of our previous system (p = 0.003). Conclusions: MBSF regularized SART reconstruction enhances MCs. The enhancement in the signals, in combination with properly designed adaptive threshold criteria, effective MC feature analysis, and false positive reduction techniques, leads to a significant improvement in the detection of clustered MCs in DBT.

Samala, Ravi K., E-mail: rsamala@umich.edu; Chan, Heang-Ping; Lu, Yao; Hadjiiski, Lubomir; Wei, Jun; Helvie, Mark A. [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-5842 (United States); Sahiner, Berkman [Center for Devices and Radiological Health, U.S. Food and Drug Administration, Maryland 20993 (United States)

2014-02-15

197

External force back-projective composition and globally deformable optimization for 3-D coronary artery reconstruction  

Science.gov (United States)

The clinical value of the 3D reconstruction of a coronary artery is important for the diagnosis and intervention of cardiovascular diseases. This work proposes a method based on a deformable model for reconstructing coronary arteries from two monoplane angiographic images acquired from different angles. First, an external force back-projective composition model is developed to determine the external force, for which the force distributions in different views are back-projected to the 3D space and composited in the same coordinate system based on the perspective projection principle of x-ray imaging. The elasticity and bending forces are composited as an internal force to maintain the smoothness of the deformable curve. Second, the deformable curve evolves rapidly toward the true vascular centerlines in 3D space and angiographic images under the combination of internal and external forces. Third, densely matched correspondence among vessel centerlines is constructed using a curve alignment method. The bundle adjustment method is then utilized for the global optimization of the projection parameters and the 3D structures. The proposed method is validated on phantom data and routine angiographic images with consideration for space and re-projection image errors. Experimental results demonstrate the effectiveness and robustness of the proposed method for the reconstruction of coronary arteries from two monoplane angiographic images. The proposed method can achieve a mean space error of 0.564 mm and a mean re-projection error of 0.349 mm.

Yang, Jian; Cong, Weijian; Chen, Yang; Fan, Jingfan; Liu, Yue; Wang, Yongtian

2014-02-01

198

Task-based assessment of breast tomosynthesis: Effect of acquisition parameters and quantum noise1  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: Tomosynthesis is a promising modality for breast imaging. The appearance of the tomosynthesis reconstructed image is greatly affected by the choice of acquisition and reconstruction parameters. The purpose of this study was to investigate the limitations of tomosynthesis breast imaging due to scan parameters and quantum noise. Tomosynthesis image quality was assessed based on performance of a mathematical observer model in a signal-known exactly (SKE) detection task.

Reiser, I.; Nishikawa, R. M.

2010-01-01

199

Recursive 3D-reconstruction of structured scenes using a moving camera - application to robotics  

International Nuclear Information System (INIS)

This thesis is devoted to the perception of a structured environment, and proposes a new method which allows a 3D-reconstruction of an interesting part of the world using a mobile camera. Our work is divided into three essential parts dedicated to 2D-information aspect, 3D-information aspect, and a validation of the method. In the first part, we present a method which produces a topologic and geometric image representation based on 'segment' and 'junction' features. Then, a 2D-matching method based on a hypothesis prediction and verification algorithm is proposed to match features issued from two successive images. The second part deals with 3D-reconstruction using a triangulation technique, and discuses our new method introducing an 'Estimation-Construction-Fusion' process. This ensures a complete and accurate 3D-representation, and a permanent position estimation of the camera with respect to the model. The merging process allows refinement of the 3D-representation using a powerful tool: a Kalman Filter. In the last part, experimental results issued from simulated and real data images are reported to show the efficiency of the method. (author)

1990-03-01

200

Applicability of 3D-CT facial reconstruction for forensic individual identification  

International Nuclear Information System (INIS)

Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using cranio metric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) cranio metric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution. (author)

2003-01-01

 
 
 
 
201

3D weighting in cone beam image reconstruction algorithms: ray-driven vs. pixel-driven.  

Science.gov (United States)

A 3D weighting scheme have been proposed previously to reconstruct images at both helical and axial scans in stat-of-the-art volumetric CT scanners for diagnostic imaging. Such a 3D weighting can be implemented in the manner of either ray-driven or pixel-drive, depending on the available computation resources. An experimental study is conducted in this paper to evaluate the difference between the ray-driven and pixel-driven implementations of the 3D weighting from the perspective of image quality, while their computational complexity is analyzed theoretically. Computer simulated data and several phantoms, such as the helical body phantom and humanoid chest phantom, are employed in the experimental study, showing that both the ray-driven and pixel-driven 3D weighting provides superior image quality for diagnostic imaging in clinical applications. With the availability of image reconstruction engine at increasing computational power, it is believed that the pixel-driven 3D weighting will be dominantly employed in state-of-the-art volumetric CT scanners over clinical applications. PMID:19163264

Tang, Xiangyang; Nilsen, Roy A; Smolin, Alex; Lifland, Ilya; Samsonov, Dmitry; Taha, Basel

2008-01-01

202

Minimizing camera-eye optical aberrations during the 3D reconstruction of retinal structures  

Science.gov (United States)

3D reconstruction of blood vessels is a powerful visualization tool for physicians, since it allows them to refer to qualitative representation of their subject of study. In this paper we propose a 3D reconstruction method of retinal vessels from fundus images. The reconstruction method propose herein uses images of the same retinal structure in epipolar geometry. Images are preprocessed by RISA system for segmenting blood vessels and obtaining feature points for correspondences. The correspondence points process is solved using correlation. The LMedS analysis and Graph Transformation Matching algorithm are used for outliers suppression. Camera projection matrices are computed with the normalized eight point algorithm. Finally, we retrieve 3D position of the retinal tree points by linear triangulation. In order to increase the power of visualization, 3D tree skeletons are represented by surfaces via generalized cylinders whose radius correspond to morphological measurements obtained by RISA. In this paper the complete calibration process including the fundus camera and the optical properties of the eye, the so called camera-eye system is proposed. On one hand, the internal parameters of the fundus camera are obtained by classical algorithms using a reference pattern. On the other hand, we minimize the undesirable efects of the aberrations induced by the eyeball optical system assuming that contact enlarging lens corrects astigmatism, spherical and coma aberrations are reduced changing the aperture size and eye refractive errors are suppressed adjusting camera focus during image acquisition. Evaluation of two self-calibration proposals and results of 3D blood vessel surface reconstruction are presented.

Aldana-Iuit, Javier; Martinez-Perez, M. Elena; Espinosa-Romero, Arturo; Diaz-Uribe, Rufino

2010-04-01

203

Use of 3D MR reconstructions in the evaluation of glenoid bone loss: a clinical study  

International Nuclear Information System (INIS)

To assess the ability of 3D MR shoulder reconstructions to accurately quantify glenoid bone loss in the clinical setting using findings at the time of arthroscopy as the gold standard. Retrospective review of patients with MR shoulder studies that included 3D MR reconstructions (3D MR) produced using an axial Dixon 3D-T1W-FLASH sequence at our institution was conducted with the following inclusion criteria: history of anterior shoulder dislocation, arthroscopy (OR) performed within 6 months of the MRI, and an estimate of glenoid bone loss made in the OR using the bare-spot method. Two musculoskeletal radiologists produced estimates of bone loss along the glenoid width, measured in mm and %, on 3D MR using the best-fit circle method, which were then compared to the OR measurements. There were a total of 15 patients (13 men, two women; mean age, 28, range, 19-51 years). There was no significant difference, on average, between the MRI (mean 3.4 mm/12.6 %; range, 0-30 %) and OR (mean, 12.7 %; range, 0-30 %) measurements of glenoid bone loss (p = 0.767). A 95 % confidence interval for the mean absolute error extended from 0.45-2.21 %, implying that, when averaged over all patients, the true mean absolute error of the MRI measurements relative to the OR measurements is expected to be less than 2.21 %. Inter-reader agreement between the two readers had an IC of 0.92 and CC of 0.90 in terms of percentage of bone loss. 3D MR reconstructions of the shoulder can be used to accurately measure glenoid bone loss. (orig.)

2014-02-01

204

Use of 3D MR reconstructions in the evaluation of glenoid bone loss: a clinical study  

Energy Technology Data Exchange (ETDEWEB)

To assess the ability of 3D MR shoulder reconstructions to accurately quantify glenoid bone loss in the clinical setting using findings at the time of arthroscopy as the gold standard. Retrospective review of patients with MR shoulder studies that included 3D MR reconstructions (3D MR) produced using an axial Dixon 3D-T1W-FLASH sequence at our institution was conducted with the following inclusion criteria: history of anterior shoulder dislocation, arthroscopy (OR) performed within 6 months of the MRI, and an estimate of glenoid bone loss made in the OR using the bare-spot method. Two musculoskeletal radiologists produced estimates of bone loss along the glenoid width, measured in mm and %, on 3D MR using the best-fit circle method, which were then compared to the OR measurements. There were a total of 15 patients (13 men, two women; mean age, 28, range, 19-51 years). There was no significant difference, on average, between the MRI (mean 3.4 mm/12.6 %; range, 0-30 %) and OR (mean, 12.7 %; range, 0-30 %) measurements of glenoid bone loss (p = 0.767). A 95 % confidence interval for the mean absolute error extended from 0.45-2.21 %, implying that, when averaged over all patients, the true mean absolute error of the MRI measurements relative to the OR measurements is expected to be less than 2.21 %. Inter-reader agreement between the two readers had an IC of 0.92 and CC of 0.90 in terms of percentage of bone loss. 3D MR reconstructions of the shoulder can be used to accurately measure glenoid bone loss. (orig.)

Gyftopoulos, Soterios; Beltran, Luis S.; Yemin, Avner; Recht, Michael P. [NYU Langone Medical Center, Department of Radiology, New York, NY (United States); Strauss, Eric; Meislin, Robert; Jazrawi, Laith [NYU Langone Medical Center, Center for Musculoskeletal Care, Department of Orthopaedic Surgery, New York, NY (United States)

2014-02-15

205

Intuitive Terrain Reconstruction Using Height Observation-Based Ground Segmentation and 3D Object Boundary Estimation  

Directory of Open Access Journals (Sweden)

Full Text Available Mobile robot operators must make rapid decisions based on information about the robot’s surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot’s array of sensors, but some upper parts of objects are beyond the sensors’ measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances.

Sungdae Sim

2012-12-01

206

Correction of head motion artifacts in SPECT with fully 3-D OS-EM reconstruction  

International Nuclear Information System (INIS)

Full text: A method which relies on continuous monitoring of head position has been developed to correct for head motion in SPECT studies of the brain. Head position and orientation are monitored during data acquisition by an inexpensive head tracking system (ADL-1, Shooting Star Technology, Rosedale, British Colombia). Motion correction involves changing the projection geometry to compensate for motion (using data from the head tracker), and reconstructing with a fully 3-D OS-EM algorithm. The reconstruction algorithm can accommodate any number of movements and any projection geometry. A single iteration of 3-D OS-EM using all available projections provides a satisfactory 3-D reconstruction, essentially free of motion artifacts. The method has been validated in studies of the 3-D Hoffman brain phantom. Multiple 36- degree acquisitions, each with the phantom in a different position, were performed on a Trionix triple head camera. Movements were simulated by combining projections from the different acquisitions. Accuracy was assessed by comparison with a motion-free reconstruction, visually and by calculating mean squared error (MSE). Motion correction reduced distortion perceptibly and, depending on the motions applied, improved MSE by up to an order of magnitude. Three-dimensional reconstruction of the 128 x 128 x 128 data set took 2- minutes on a SUN Ultra 1 workstation. This motion correction technique can be retro-fitted to existing SPECT systems and could be incorporated in future SPECT camera designs. It appears to be applicable in PET as well as SPECT, to be able to correct for any head movements, and to have the potential to improve the accuracy of tomographic brain studies under clinical imaging conditions

1998-03-01

207

3D Reconstruction of Ultrasonic Images Based on Matlab/Simulink  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study we use Matlab/Simulink as a user friendly interface to examine three recent works on UT image processing; furthermore a new method based on morphological features is proposed. A series of simulated 2D UT images of two known cysts are processed by the 4 different methods. They will serve as the input for 3D surface reconstruction package. A novel comparison way related to 2D and 3D features of cysts is provided. The weakness, the advantages and the deficiencies of each method are...

2006-01-01

208

3-D-environment reconstruction for mobile robots using fast- SLAM and feature extraction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes an algorithm that can be used to reconstruct a 3-D environment on a mobile robot. As sensors, color and time-of-flight cameras are used. 2-D features are extracted from color images and assigned 3-D coordinates. Those are the input for a modified fastSLAM algorithm that is capable of rendering environment maps for small environments online in order to execute manipulation tasks. The method is evaluated on the service robot Care-O-bot®3.

2010-01-01

209

3D reconstruction of hollow parts analyzing images acquired by a fiberscope  

Science.gov (United States)

A modified fiberscope used to reconstruct difficult-to-reach inner structures is presented. By substituting the fiberscope’s original illumination system, we can project a profile-revealing light line inside the object of study. The light line is obtained using a sandwiched power light-emitting diode (LED) attached to an extension arm on the tip of the fiberscope. Profile images from the interior of the object are then captured by a camera attached to the fiberscope’s eyepiece. Using a series of those images at different positions, the system is capable of generating a 3D reconstruction of the object with submillimeter accuracy. Also proposed is the use of a combination of known filters to remove the honeycomb structures produced by the fiberscope and the use of ring gages to obtain the extrinsic parameters of the camera attached to the fiberscope and the metrological traceability of the system. Several standard ring diameter measurements were compared against their certified values to improve the accuracy of the system. To exemplify an application, a 3D reconstruction of the interior of a refrigerator duct was conducted. This reconstruction includes accuracy assessment by comparing the measurements of the system to a coordinate measuring machine. The system, as described, is capable of 3D reconstruction of the interior of objects with uniform and non-uniform profiles from 10 to 60 mm in transversal dimensions and a depth of 1000 mm if the material of the walls of the object is translucent and allows the detection of the power LED light from the exterior through the wall. If this is not possible, we propose the use of a magnetic scale which reduces the working depth to 170 mm. The assessed accuracy is around ±0.15 mm in 2D cross-section reconstructions and ±1.3 mm in 1D position using a magnetic scale, and ±0.5 mm using a CCD camera.

Icasio-Hernández, Octavio; Gonzalez-Barbosa, José-Joel; Hurtado-Ramos, Juan B.; Viliesid-Alonso, Miguel

2014-07-01

210

Application of 3D Photo-reconstruction techniques in Geomorphology: Examples through different landforms and scales  

Science.gov (United States)

Recent developments made in tri-dimensional photo-reconstruction techniques (3D-PR), such as the use of Structure from Motion (SfM) and MultiView Stereo (MVS) techniques together, have allowed obtaining high resolution 3D point clouds. In order to achieve final point clouds with these techniques, only oblique images from consumer un-calibrated and non-metric cameras are needed. Here, these techniques are used in order to measure, monitor and quantify geomorphological features and processes. Three different applications through a range of scales and landforms are presented here. Firstly, five small gully headcuts located in a small catchment in SW Spain were monitored with the aim of estimating headcut retreat rates. During this field work, 3D models obtained by means of a Terrestrial Laser Scanner (TLS) were captured and used as benchmarks to analyze 3D-PR method accuracy. Results of this analysis showed centimeter-level accuracies with average distances between the 3D-PR model and the TLS model ranging from 0.009 to 0.025 m. Estimated soil loss ranged from -0.246 m3 to 0.114 m3 for a wet period (289 mm) of 54 days in 2013. Secondly, a calanchi type badland in Sicily (Italy) was photo-reconstructed and the quality of the 3D-PR model was analyzed using a Digital Elevation Model produced by classic digital photogrammetry with photos captured by an Unmanned Aerial Vehicle (UAV). In this case, sub-meter calculated accuracies (0.30) showed that it is possible to describe badland morphology using 3D-PR models but it is not feasible to use these models to quantify annual rates of soil erosion in badlands (10 mm eroded per year). Finally, a high-resolution model of the Veleta rock glacier (in SE Spain) was elaborated with 3D-PR techniques and compared with a 3D model obtained by means of a TLS. Results indicated that 3D-PR method can be applied to the micro-scale study of glacier morphologies and processes with average distances to the TLS point cloud of 0.21 m.

Gómez-Gutiérrez, Álvaro; Susanne, Schnabel; Conoscenti, Christian; Caraballo-Arias, Nathalie A.; Ferro, Vito; di Stefano, Constanza; Juan de Sanjosé, José; Berenguer-Sempere, Fernando; de Matías, Javier

2014-05-01

211

Combination of SANS and 3D stochastic reconstruction techniques for the study of nanostructured materials  

CERN Document Server

Ceramic nanostructured materials have recently received scientific and industrial interest due to their unique properties. A series of such nanoporous structures were characterised by SANS techniques. The resulting scattering curves were analysed to obtain basic structural information regarding the pore size distribution and autocorrelation function of each material. Furthermore, stochastic reconstruction models were employed to generate 3D images with the same basic structural characteristics obtained from SANS. Finally, simulation results of permeation on the reconstructed images provide very good agreement with experimental data. (orig.)

Kikkinides, E S; Steriotis, T A; Kanellopoulos, N K; Mitropoulos, A C; Treimer, W

2002-01-01

212

Robust Stereo-Vision Based 3D Object Reconstruction for the Assistive Robot FRIEND  

Directory of Open Access Journals (Sweden)

Full Text Available A key requirement of assistive robot vision is the robust 3D object reconstruction in complex environments for reliable autonomous object manipulation. In this paper the idea is presented of achieving high robustness of a complete robot vision system against external influences such as variable illumination by including feedback control of the object segmentation in stereo images. The approach used is to change the segmentation parameters in closed-loop so that object features extraction is driven to a desired result. Reliable feature extraction is necessary to fully exploit a neuro-fuzzy classifier which is the core of the proposed 2D object recognition method, predecessor of 3D object reconstruction. Experimental results on the rehabilitation assistive robotic system FRIEND demonstrate the effectiveness of the proposed method.

COJBASIC, Z.

2011-11-01

213

Utility of reconstructed image from 3-D MRI in the region of oral cavity  

International Nuclear Information System (INIS)

The 3-D MRI with short TR was performed in the region of oral cavity, jaw and face, and utility of the reconstructed image was examined. Subjects were 8 healthy volunteers and 12 patients. The 3-D MRI was performed using SPGR with the following parameters; TR: 8 or 9 msec, TE: 2 or 3 msec, and FA: 20-30 degrees. Imaging direction was vertical to body axis. The matrix number was 256 x 192, slice thickness was 1 mm, slice interval was 0 and slice number was 128. The obtained image was reconstructed using software Reformat''. Detectability of temporomandibular joint disc was not enough in 8 of 20 cases. Detectability of mandibular canal was clear in 18 of 20 cases. In panorama MRI, soft tissue such as submandibular gland was detected. But, in hard tissue such as teeth or maxilla, there was a more little information in panorama MRI than in panorama X-ray photography. (K.H.)

1998-12-01

214

The Isprs Benchmark on Urban Object Classification and 3d Building Reconstruction  

Science.gov (United States)

For more than two decades, many efforts have been made to develop methods for extracting urban objects from data acquired by airborne sensors. In order to make the results of such algorithms more comparable, benchmarking data sets are of paramount importance. Such a data set, consisting of airborne image and laserscanner data, has been made available to the scientific community. Researchers were encouraged to submit results of urban object detection and 3D building reconstruction, which were evaluated based on reference data. This paper presents the outcomes of the evaluation for building detection, tree detection, and 3D building reconstruction. The results achieved by different methods are compared and analysed to identify promising strategies for automatic urban object extraction from current airborne sensor data, but also common problems of state-of-the-art methods.

Rottensteiner, F.; Sohn, G.; Jung, J.; Gerke, M.; Baillard, C.; Benitez, S.; Breitkopf, U.

2012-07-01

215

In-line monitoring and reverse 3D model reconstruction in additive manufacturing  

DEFF Research Database (Denmark)

Additive manufacturing allows for close-to unrestrained geometrical freedom in part design. The ability to manufacture geometries of such complexity is however limited by the fact that it proves difficult to verify tolerances of these parts. Tolerancs of featuress that are inaccessible with traditional measuring equipment such as Coordinate Measurement Machines (CMM's) can not easily be verified. This paradox is addresses by the proposal of an in-line reverse engineering and 3D reconstruction method that alows for a true to scale reconstruction of a part that is being additivelymanufactures on 3D printing (3DP), or Selective Laser Sintering (SLS) equipment. The system will be implemented and tested on a 3DP machine with modifications developed at the author's university.

Pedersen, David Bue Technical University of Denmark,

2010-01-01

216

Estimation of solar prominence magnetic fields based on the reconstructed 3D trajectories of prominence knots  

CERN Document Server

We present an estimation of the lower limits of local magnetic fields in quiescent, activated, and active (surges) promineces, based on reconstructed 3-dimensional (3D) trajectories of individual prominence knots. The 3D trajectories, velocities, tangential and centripetal accelerations of the knots were reconstructed using observational data collected with a single ground-based telescope equipped with a Multi-channel Subtractive Double Pass imaging spectrograph. Lower limits of magnetic fields channeling observed plasma flows were estimated under assumption of the equipartition principle. Assuming approximate electron densities of the plasma n_e = 5*10^{11} cm^{-3} in surges and n_e = 5*10^{10} cm^{-3} in quiescent/activated prominences, we found that the magnetic fields channeling two observed surges range from 16 to 40 Gauss, while in quiescent and activated prominences they were less than 10 Gauss. Our results are consistent with previous detections of weak local magnetic fields in the solar prominences.

Zapiór, Maciej

2012-01-01

217

Results of the ISPRS benchmark on urban object detection and 3D building reconstruction  

Science.gov (United States)

For more than two decades, many efforts have been made to develop methods for extracting urban objects from data acquired by airborne sensors. In order to make the results of such algorithms more comparable, benchmarking data sets are of paramount importance. Such a data set, consisting of airborne image and laserscanner data, has been made available to the scientific community by ISPRS WGIII/4. Researchers were encouraged to submit their results of urban object detection and 3D building reconstruction, which were evaluated based on reference data. This paper presents the outcomes of the evaluation for building detection, tree detection, and 3D building reconstruction. The results achieved by different methods are compared and analysed to identify promising strategies for automatic urban object extraction from current airborne sensor data, but also common problems of state-of-the-art methods.

Rottensteiner, Franz; Sohn, Gunho; Gerke, Markus; Wegner, Jan Dirk; Breitkopf, Uwe; Jung, Jaewook

2014-07-01

218

Reconstruction of 3d Objects of Assets and Facilities by Using Benchmark Points  

Science.gov (United States)

Acquiring and modeling 3D geo-data of building assets and facility objects is one of the challenges. A number of methods and technologies are being utilized for this purpose. Total station, GPS, photogrammetric and terrestrial laser scanning are few of these technologies. In this paper, points commonly shared by potential facades of assets and facilities modeled from point clouds are identified. These points are useful for modeling process to reconstruct 3D models of assets and facilities stored to be used for management purposes. These models are segmented through different planes to produce accurate 2D plans. This novel method improves the efficiency and quality of construction of models of assets and facilities with the aim utilize in 3D management projects such as maintenance of buildings or group of items that need to be replaced, or renovated for new services.

Baig, S. U.; Rahman, A. A.

2013-08-01

219

A new reconstruction method for 3D buildings from 2D vector floor plan  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a method to analyze the geometry and semantic information of2D vector floor plans, and reconstruct the corresponding 3D building modelsautomatically. First, the Shape-opening graph (SOG) is introduced to recognizeStructural Components (SCs) and describe the relationships between SCs and openingswhich are architectural components separating spaces. A priority principle algorithmis developed to replace openings with wall equivalent lines for the purpose of laterloop searchin...

2013-01-01

220

Radar investigation on civil structures using 3D data reconstruction and transmission tomography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Non-destructive investigation using Ground Penetrating Radar is becoming more popular during the inspection of civil structures. Currently, traditional 2D imaging is also used as a preliminary tool to find possible areas of interest for more detailed inspection, which can be accomplished by 3D image reconstruction or tomography techniques. In this paper, a general overview of the work done at University of Minho regarding these techniques is presented. Data acquisition was performed on two ma...

Topczewski, Lukasz; Fernandes, Francisco M.; Cruz, Paulo J. S.; Lourenc?o, Paulo B.; Ramos, Lui?s F.

2006-01-01

 
 
 
 
221

3D reconstruction from a monocular vision system for unmanned ground vehicles  

Science.gov (United States)

In this paper we present a 3D reconstruction technique designed to support an autonomously navigated unmanned system. The algorithm and methods presented focus on the 3D reconstruction of a scene, with color and distance information, using only a single moving camera. In this way, the system may provide positional self-awareness for navigation within a known, GPS-denied area. It can also be used to construct a new model of unknown areas. Existing 3D reconstruction methods for GPS-denied areas often rely on expensive inertial measurement units to establish camera location and orientation. The algorithm proposed---after the preprocessing tasks of stabilization and video enhancement---performs Speeded-Up Robust Feature extraction, in which we locate unique stable points within every frame. Additional features are extracted using an optical flow method, with the resultant points fused and pruned based on several quality metrics. Each unique point is then tracked through the video sequence and assigned a disparity value used to compute the depth for each feature within the scene. The algorithm also assigns each feature point a horizontal and vertical coordinate using the camera's field of views specifications. From this, a resultant point cloud consists of thousands of feature points plotted from a particular camera position and direction, generated from pairs of sequential frames. The proposed method can use the yaw, pitch and roll information calculated from visual cues within the image data to accurately compute location and orientation. This positioning information enables the reconstruction of a robust 3D model particularly suitable for autonomous navigation and mapping tasks.

Tompkins, R. Cortland; Diskin, Yakov; Youssef, Menatoallah M.; Asari, Vijayan K.

2011-10-01

222

CUDA based Level Set Method for 3D Reconstruction of Fishes from Large Acoustic Data  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Acoustic images present views of underwater dynamics, even in high depths. With multi-beam echo sounders (SONARs), it is possible to capture series of 2D high resolution acoustic images. 3D reconstruction of the water column and subsequent estimation of fish abundance and fish species identification is highly desirable for planning sustainable fisheries. Main hurdles in analysing acoustic images are the presence of speckle noise and the vast amount of acoustic data. This paper presents a leve...

2009-01-01

223

Practical implications of GPR investigation using 3D data reconstruction and transmission tomography  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Non-destructive investigation using ground penetrating radar is becoming more popular in the inspection of civil structures. Currently, traditional 2D imaging is used as a preliminary tool to fi nd possible areas of interest for more detailed inspection, which can be accomplished by more advanced techniques like 3D image reconstruction or tomography. In this paper, a general overview of the work done at University of Minho regarding these techniques is presented, together wi...

Topczewski, Lukasz; Fernandes, Francisco M.; Cruz, Paulo J. S.; Lourenc?o, Paulo B.

2007-01-01

224

In-line monitoring and reverse 3D model reconstruction in additive manufacturing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Additive manufacturing allows for close-to unrestrained geometrical freedom in part design. The ability to manufacture geometries of such complexity is however limited by the fact that it proves difficult to verify tolerances of these parts. Tolerancs of featuress that are inaccessible with traditional measuring equipment such as Coordinate Measurement Machines (CMM's) can not easily be verified. This paradox is addresses by the proposal of an in-line reverse engineering and 3D reconstruction...

Pedersen, David Bue; Hansen, Hans Nørgaard; Nielsen, Jakob Skov

2010-01-01

225

An Analytical Review of Stereovision Techniques to Reconstruct 3D Coordinates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Stereovision based on 3D environment reconstruction provides a true picture of real world situations for detection of objects’ locations. This approach has specific use in the scenarios like identifying traffic jams on the roads, locating curves and bends on the roads, finding obstacles in the construction sites, etc. This paper describes different methods used in stereovision to detect images like use of trinocular stereovision, calculating correlation between left and right contours for a...

2013-01-01

226

Semantic-based Technique for the Automation the 3D Reconstruction Process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The reconstruction of 3D objects based on point clouds data presents a major task in many application field since it consumes time and require human interactions to yield a promising result. Robust and quick methods for complete object extraction or identification are still an ongoing research topic and suffer from the complex structure of the data, which cannot be sufficiently modeled by purely numerical strategies. Our work aims at defining a new way of automatically and intelligently proce...

2010-01-01

227

Optimal calibration marker mesh for 2D X-ray sensors in 3D reconstruction.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Image intensifiers suffer from distortions due to magnetic fields. In order to use this X-ray projections images for computer-assisted medical interventions, image intensifiers need to be calibrated. Opaque markers are often used for the correction of the image distortion and the estimation of the acquisition geometry parameters. Information under the markers is then lost. In this work, we consider the calibration of image intensifiers in the framework of 3D reconstruction from several 2D X-r...

Desbat, Laurent; Mennessier, Catherine; Champleboux, Guillaume

2002-01-01

228

3D Reconstruction Using Interval Methods on The Kinect Device Coupled With an IMU  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The principle behind VSLAM applications like 3D object reconstruction or indoor mapping is to estimate the spatial transformation between two large clouds of points, which represent two poses of the same scene. They can further be processed to obtain detailed surfaces. Since its introduction in 1992, the standard algorithm for finding the alignment between two point clouds is ICP (Iterative Closest Point) and its variants, combined with RANSAC (RANdom SAmple Consensus). This paper presents a ...

2012-01-01

229

Calculating the axes of rotation for the subtalar and talocrural joints using 3D bone reconstructions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Orientation of the subtalar joint axis dictates inversion and eversion movements of the foot and has been the focus of evolutionary and clinical studies for a number of years. Previous studies have measured the subtalar joint axis against the axis of the whole foot, the talocrural joint axis and, recently, the principal axes of the talus. The present study introduces a new method for estimating average joint axes from 3D reconstructions of bones and applies the method to the talus to calculat...

2012-01-01

230

3-D reconstruction of an ancient Egyptian mummy using X-ray computer tomography.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Computer tomography has been used to image and reconstruct in 3-D an Egyptian mummy from the collection of the British Museum. This study of Tjentmutengebtiu, a priestess from the 22nd dynasty (945-715 BC) revealed invaluable information of a scientific, Egyptological and palaeopathological nature without mutilation and destruction of the painted cartonnage case or linen wrappings. Precise details on the removal of the brain through the nasal cavity and the viscera from the abdominal cavity w...

Baldock, C.; Hughes, S. W.; Whittaker, D. K.; Taylor, J.; Davis, R.; Spencer, A. J.; Tonge, K.; Sofat, A.

1994-01-01

231

Structural analysis: a tool for testing 3D computer reconstructions of Thule whalebone houses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

One criticism of computer modeling in archaeology is that the visual products suggest a higher degree of knowledge of the structure or site than the data warrant, and that they represent only one of several possible outcomes. This paper discusses the benefits of structural analysis as a means of testing 3D computer reconstructions based on limited archaeological data. Thule Inuit whalebone houses will be used as case studies for testing structural behavior. The Thule people are the cultural a...

Levy, Richard; Dawson, Peter

2008-01-01

232

Towards unbiased 3D reconstruction : in single-particle cryo-electron microscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cryo-electron microscopy of freestanding molecules (single-particles) plays a pivotal role in the difficult and pressing challenge of determining the structures of large macromolecular complexes. Molecular volumes are generated by aligning large sets of randomly oriented two-dimensional (2D) projection images in three dimensions (3D) before reconstruction is performed using tomographic techniques. The increasing popularity of the single-particle method is highly correlated with technical adva...

2010-01-01

233

Three dimensional CT reconstruction: a comparison between 2D, 3D CT and original anatomical structures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Conventional two dimensional computed tomography has provided significant advancement in clinical diagnosis with information on cross-sectional anatomy of various parts of the body. However, three dimensional representations are not directly available. This is now made possible by recent development of CAD software and CT equipments and technique such as multiplanar reformation capable of providing 3D reconstruction using 2D CT data. This article evaluates the accuracy of measurements and dim...

Markose, Eldho; Vikraman, B.; Veerabahu, M.

2009-01-01

234

Technique for 3D shape reconstruction of spherical and aspheric surfaces using deflectometric principle  

Directory of Open Access Journals (Sweden)

Full Text Available We provide a description and analysis of a deflectometric technique for 3D measurements of optically smooth surfaces. It is presented that a surface reconstruction problem leads to a theoretical description by a nonlinear partial differential equation. Then, a surface shape can be calculated by solution of a derived equation. The presented method is noncontact and no reference surface is needed as in interferometry.

Novák P.

2013-05-01

235

3D Identification and Reconstruction of z~1 Clusters: Prospects for the DEEP2 Redshift Survey  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have developed a geometrical method based on 3D Voronoi polyhedra and Delaunay tessellation for identifying and reconstructing clusters of galaxies in the next generation of deep, flux-limited redshift surveys. We here describe this algorithm and tests of it using mock catalogs that simulate the DEEP2/DEIMOS redshift survey, which will begin observations in the Spring of 2002 and will provide a detailed three dimensional map of the large scale structure up to redshift 1.5.

Marinoni, Christian; Davis, Marc; Newman, Jeffrey A.; Coil, Alison L.

2001-01-01

236

Regularization design in penalized maximum-likelihood image reconstruction for lesion detection in 3D PET  

Science.gov (United States)

Detecting cancerous lesions is a major clinical application in emission tomography. In previous work, we have studied penalized maximum-likelihood (PML) image reconstruction for the detection task and proposed a method to design a shift-invariant quadratic penalty function to maximize detectability of a lesion at a known location in a two dimensional image. Here we extend the regularization design to maximize detectability of lesions at unknown locations in fully 3D PET. We used a multiview channelized Hotelling observer (mvCHO) to assess the lesion detectability in 3D images to mimic the condition where a human observer examines three orthogonal views of a 3D image for lesion detection. We derived simplified theoretical expressions that allow fast prediction of the detectability of a 3D lesion. The theoretical results were used to design the regularization in PML reconstruction to improve lesion detectability. We conducted computer-based Monte Carlo simulations to compare the optimized penalty with the conventional penalty for detecting lesions of various sizes. Only true coincidence events were simulated. Lesion detectability was also assessed by two human observers, whose performances agree well with that of the mvCHO. Both the numerical observer and human observer results showed a statistically significant improvement in lesion detection by using the proposed penalty function compared to using the conventional penalty function.

Yang, Li; Zhou, Jian; Ferrero, Andrea; Badawi, Ramsey D.; Qi, Jinyi

2014-01-01

237

Regularization design in penalized maximum-likelihood image reconstruction for lesion detection in 3D PET.  

Science.gov (United States)

Detecting cancerous lesions is a major clinical application in emission tomography. In previous work, we have studied penalized maximum-likelihood (PML) image reconstruction for the detection task and proposed a method to design a shift-invariant quadratic penalty function to maximize detectability of a lesion at a known location in a two dimensional image. Here we extend the regularization design to maximize detectability of lesions at unknown locations in fully 3D PET. We used a multiview channelized Hotelling observer (mvCHO) to assess the lesion detectability in 3D images to mimic the condition where a human observer examines three orthogonal views of a 3D image for lesion detection. We derived simplified theoretical expressions that allow fast prediction of the detectability of a 3D lesion. The theoretical results were used to design the regularization in PML reconstruction to improve lesion detectability. We conducted computer-based Monte Carlo simulations to compare the optimized penalty with the conventional penalty for detecting lesions of various sizes. Only true coincidence events were simulated. Lesion detectability was also assessed by two human observers, whose performances agree well with that of the mvCHO. Both the numerical observer and human observer results showed a statistically significant improvement in lesion detection by using the proposed penalty function compared to using the conventional penalty function. PMID:24351981

Yang, Li; Zhou, Jian; Ferrero, Andrea; Badawi, Ramsey D; Qi, Jinyi

2014-01-20

238

Real-time 3D human pose recognition from reconstructed volume via voxel classifiers  

Science.gov (United States)

This paper presents a human pose recognition method which simultaneously reconstructs a human volume based on ensemble of voxel classifiers from a single depth image in real-time. The human pose recognition is a difficult task since a single depth camera can capture only visible surfaces of a human body. In order to recognize invisible (self-occluded) surfaces of a human body, the proposed algorithm employs voxel classifiers trained with multi-layered synthetic voxels. Specifically, ray-casting onto a volumetric human model generates a synthetic voxel, where voxel consists of a 3D position and ID corresponding to the body part. The synthesized volumetric data which contain both visible and invisible body voxels are utilized to train the voxel classifiers. As a result, the voxel classifiers not only identify the visible voxels but also reconstruct the 3D positions and the IDs of the invisible voxels. The experimental results show improved performance on estimating the human poses due to the capability of inferring the invisible human body voxels. It is expected that the proposed algorithm can be applied to many fields such as telepresence, gaming, virtual fitting, wellness business, and real 3D contents control on real 3D displays.

Yoo, ByungIn; Choi, Changkyu; Han, Jae-Joon; Lee, Changkyo; Kim, Wonjun; Suh, Sungjoo; Park, Dusik; Kim, Junmo

2014-03-01

239

3D shape reconstruction from relief calculation: application to human body  

Directory of Open Access Journals (Sweden)

Full Text Available In experimental mechanics especially in experimental biomechanics, evaluating a volume object is a major research axe. In mechanics, 3D reconstruction is made from different optical methods like stereovision [1] or structured light methods. In biomechanics, it is achieved from tomography techniques or from models which divide human body into 15, 16 and 17 polyarticulated solids [2][3]. Those solids are simple volumes (cylinders, spheres. In this review, a method of 3D reconstruction from two calculated relief is proposed. Then, the geometric parameters are extracted using an algorithm and compared to the real dimension of various objects. The first test consist in studying the feasibility of the 3D reconstruction using a real upper arm and a mannequin. In a second test an analysis of a sphere and two cylinders which have different dimensions is performed. The aim of those last tests is to evaluate the performances of the proposed method, to show distortion volume problems and to propose solutions.

Valle V.

2010-06-01

240

Applicator reconstruction in MRI 3D image-based dose planning of brachytherapy for cervical cancer  

DEFF Research Database (Denmark)

BACKGROUND AND PURPOSE: To elaborate a method for applicator reconstruction for MRI-based brachytherapy for cervical cancer. MATERIALS AND METHODS: Custom-made plastic catheters with a copper sulphate solution were made for insertion in the source channels of MR-CT compatible applicators: plastic and titanium tandem ring applicators, and titanium needles. The applicators were CT and MR scanned in a phantom for accurate 3D assessment of applicator visibility and geometry. A reconstruction method was developed and evaluated in 19 patient MR examinations with ring applicator (plastic: 14, titanium: 5). MR applicator reconstruction uncertainties related to inter-observer variation were evaluated. RESULTS: The catheters were visible in the plastic applicator on T1-weighted images in phantom and in 14/14 clinical applications. On T2-weighted images, the catheters appeared weaker but still visible in phantom and in 13/14 MR clinical applications. In the titanium applicator, the catheters could not be separated from the artifacts from the applicator itself. However, these artifacts could be used to localize both titanium ring applicator (5/5 clinical applications) and needles (6/6 clinical applications). Standard deviations of inter-observer differences were below 2mm in all directions. CONCLUSION: 3D applicator reconstruction based on MR imaging could be performed for plastic and titanium applicators. Plastic applicators proved well to be suited for MRI-based reconstruction. For improved practicability of titanium applicator reconstruction, development of MR applicator markers is essential. Reconstruction of titanium applicator and needles at 1.5T MR requires geometric evaluations in phantoms before using the applicator in patients.

Haack, Søren; Nielsen, Søren Kynde

2009-01-01

 
 
 
 
241

3D Coronal Density Reconstruction and Retrieving the Magnetic Field Structure during Solar Minimum  

CERN Multimedia

Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal phenomena at all scales. We employed STEREO/COR1 data obtained during a deep minimum of solar activity in February 2008 (Carrington rotation CR 2066) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 Rsun using a tomography method. With this, we qualitatively deduced structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in the 195 A band obtained by tomography for the same CR. A global 3D MHD model of the solar corona was used to relate the reconstructed 3D density and emissivity to open/closed magnetic field structures. We show that the density maximum locations can serve as an indicator of current sheet position, while the locations of the density gradient maximum can be a reliable indicator of coronal hole boundaries. We find that the magnetic field configuration du...

Kramar, M; Miki?, Z; Davila, J

2014-01-01

242

3D nanostructure reconstruction based on the SEM imaging principle, and applications  

Science.gov (United States)

This paper addresses a novel 3D reconstruction method for nanostructures based on the scanning electron microscopy (SEM) imaging principle. In this method, the shape from shading (SFS) technique is employed, to analyze the gray-scale information of a single top-view SEM image which contains all the visible surface information, and finally to reconstruct the 3D surface morphology. It offers not only unobstructed observation from various angles but also the exact physical dimensions of nanostructures. A convenient and commercially available tool (NanoViewer) is developed based on this method for nanostructure analysis and characterization of properties. The reconstruction result coincides well with the SEM nanostructure image and is verified in different ways. With the extracted structure information, subsequent research of the nanostructure can be carried out, such as roughness analysis, optimizing properties by structure improvement and performance simulation with a reconstruction model. Efficient, practical and non-destructive, the method will become a powerful tool for nanostructure surface observation and characterization.

Zhu, Fu-Yun; Wang, Qi-Qi; Zhang, Xiao-Sheng; Hu, Wei; Zhao, Xin; Zhang, Hai-Xia

2014-05-01

243

3-D reconstruction of a human fetus with combined holoprosencephaly and cyclopia  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The purpose of this study was to examine a human fetus with combined holoprosencephaly and cyclopia by means of histology and 3-D reconstruction to determine the internal structure and extent of the malformation. Methods The head from a human fetus at 20 weeks gestation and a diagnosis of holoprosencephaly and cyclopia was investigated histologically and three-dimensionally reconstructed with CAD techniques. The cranial bones, blood vessels, nerves, eye and brain anlagen were reconstructed. Results The 3-D reconstruction revealed both severe malformation and absence of the facial midline bones above the maxilla, and a malformation of the maxilla and sphenoid bone. The mandible, posterior cranial bones, cranial nerves and blood vessels were normal. A synophthalmic eye with two lenses was found. The prosencephalon was a single small protrusion above the diencephalon. No nasal cavity was present. Above the single eye a proboscis was found. Conclusion The absence of the facial midline bones above the maxilla and the presence of a proboscis as a nose-like structure above the cyclopic eye both mean that there was a developmental defect in the fronto-nasal facial process of this fetus.

Meiselbach Veronika

2009-06-01

244

Test of 3D CT reconstructions by EM + TV algorithm from undersampled data  

Energy Technology Data Exchange (ETDEWEB)

Computerized tomography (CT) plays an important role in medical imaging for diagnosis and therapy. However, CT imaging is connected with ionization radiation exposure of patients. Therefore, the dose reduction is an essential issue in CT. In 2011, the Expectation Maximization and Total Variation Based Model for CT Reconstruction (EM+TV) was proposed. This method can reconstruct a better image using less CT projections in comparison with the usual filtered back projection (FBP) technique. Thus, it could significantly reduce the overall dose of radiation in CT. This work reports the results of an independent numerical simulation for cone beam CT geometry with alternative virtual phantoms. As in the original report, the 3D CT images of 128 Multiplication-Sign 128 Multiplication-Sign 128 virtual phantoms were reconstructed. It was not possible to implement phantoms with lager dimensions because of the slowness of code execution even by the CORE i7 CPU.

Evseev, Ivan; Ahmann, Francielle; Silva, Hamilton P. da [Universidade Tecnologica Federal do Parana - UTFPR/FB, 85601-970, Caixa Postal 135, Francisco Beltrao - PR (Brazil); Schelin, Hugo R. [Universidade Tecnologica Federal do Parana-UTFPR/FB,85601-970,Caixa Postal 135,Francisco Beltrao-PR (Brazil) and Faculdades Pequeno Principe-FPP, Av. Iguacu, 333, Rebou (Brazil); Yevseyeva, Olga [Universidade Federal de Santa Catarina - UFSC/ARA, 88900-000, Rua Pedro Joao Pereira, 150, Ararangua - SC (Brazil); Klock, Margio C. L. [Universidade Federal do Parana - UFPR Litoral, 80230-901, Rua Jaguaraiva 512, Caioba, Matinhos - PR (Brazil)

2013-05-06

245

Direct fourier methods in 3D-reconstruction from cone-beam data  

International Nuclear Information System (INIS)

The problem of 3D-reconstruction is encountered in both medical and industrial applications of X-ray tomography. A method able to utilize a complete set of projections complying with Tuys condition was proposed by Grangeat. His method is mathematically exact and consists of two distinct phases. In phase 1 cone-beam projection data are used to produce the derivative of the radon transform. In phase 2, after interpolation, the radon transform data are used to reconstruct the three-dimensional object function. To a large extent our method is an extension of the Grangeat method. Our aim is to reduce the computational complexity, i.e. to produce a faster method. The most taxing procedure during phase 1 is computation of line-integrals in the detector plane. By applying the direct Fourier method in reverse for this computation, we reduce the complexity of phase 1 from O(N"4) to O(N"3logN). Phase 2 can be performed either as a straight 3D-reconstruction or as a sequence of two 2D-reconstructions in vertical and horizontal planes, respectively. Direct Fourier methods can be applied for the 2D- and for the 3D-reconstruction, which reduces the complexity of phase 2 from O(N"4) to O(N"3logN) as well. In both cases, linogram techniques are applied. For 3D-reconstruction the inversion formula contains the second derivative filter instead of the well-known ramp-filter employed in the 2D-case. The derivative filter is more well-behaved than the 2D ramp-filter. This implies that less zeropadding is necessary which brings about a further reduction of the computational efforts. The method has been verified by experiments on simulated data. The image quality is satisfactory and independent of cone-beam angles. For a 512"3 volume we estimate that our method is ten times faster than Grangeats method

1994-06-01

246

3D reconstruction of digitized histological sections for vasculature quantification in the mouse hind limb  

Science.gov (United States)

In contrast to imaging modalities such as magnetic resonance imaging and micro computed tomography, digital histology reveals multiple stained tissue features at high resolution (0.25?m/pixel). However, the two-dimensional (2D) nature of histology challenges three-dimensional (3D) quantification and visualization of the different tissue components, cellular structures, and subcellular elements. This limitation is particularly relevant to the vasculature, which has a complex and variable structure within tissues. The objective of this study was to perform a fully automated 3D reconstruction of histology tissue in the mouse hind limb preserving the accurate systemic orientation of the tissues, stained with hematoxylin and immunostained for smooth muscle ? actin. We performed a 3D reconstruction using pairwise rigid registrations of 5?m thick, paraffin-embedded serial sections, digitized at 0.25?m/pixel. Each registration was performed using the iterative closest points algorithm on blood vessel landmarks. Landmarks were vessel centroids, determined according to a signed distance map of each pixel to a decision boundary in hue-saturation-value color space; this decision boundary was determined based on manual annotation of a separate training set. Cell nuclei were then automatically extracted and corresponded to refine the vessel landmark registration. Homologous nucleus landmark pairs appearing on not more than two adjacent slides were chosen to avoid registrations which force curved or non-sectionorthogonal structures to be straight and section-orthogonal. The median accumulated target registration errors ± interquartile ranges for the vessel landmark registration, and the nucleus landmark refinement were 43.4+/-42.8?m and 2.9+/-1.7?m, respectively (p<0.0001). Fully automatic and accurate 3D rigid reconstruction of mouse hind limb histology imaging is feasible based on extracted vasculature and nuclei.

Xu, Yiwen; Pickering, J. Geoffrey; Nong, Zengxuan; Gibson, Eli; Ward, Aaron D.

2014-03-01

247

3D reconstruction of internal structure of animal body using near-infrared light  

Science.gov (United States)

To realize three-dimensional (3D) optical imaging of the internal structure of animal body, we have developed a new technique to reconstruct CT images from two-dimensional (2D) transillumination images. In transillumination imaging, the image is blurred due to the strong scattering in the tissue. We had developed a scattering suppression technique using the point spread function (PSF) for a fluorescent light source in the body. In this study, we have newly proposed a technique to apply this PSF for a light source to the image of unknown light-absorbing structure. The effectiveness of the proposed technique was examined in the experiments with a model phantom and a mouse. In the phantom experiment, the absorbers were placed in the tissue-equivalent medium to simulate the light-absorbing organs in mouse body. Near-infrared light was illuminated from one side of the phantom and the image was recorded with CMOS camera from another side. Using the proposed techniques, the scattering effect was efficiently suppressed and the absorbing structure can be visualized in the 2D transillumination image. Using the 2D images obtained in many different orientations, we could reconstruct the 3D image. In the mouse experiment, an anesthetized mouse was held in an acrylic cylindrical holder. We can visualize the internal organs such as kidneys through mouse's abdomen using the proposed technique. The 3D image of the kidneys and a part of the liver were reconstructed. Through these experimental studies, the feasibility of practical 3D imaging of the internal light-absorbing structure of a small animal was verified.

Tran, Trung Nghia; Yamamoto, Kohei; Namita, Takeshi; Kato, Yuji; Shimizu, Koichi

2014-03-01

248

Reconstruction of the 3D flow field in a differentially heated rotating annulus laboratory experiment  

Science.gov (United States)

In the earth's atmosphere baroclinic instability is responsible for the heat and momentum transport from low to high latitudes. In the fifties, Raymond Hide used a rather simple laboratory experiment to study such vortices in the lab. The experiment is comprised by a cooled inner and heated outer cylinder mounted on a rotating platform, which mimics the heated tropical and cooled polar regions of the earth's atmosphere. The experiment shows rich dynamics that have been studied by varying the radial temperature difference and the rate of annulus revolution. At the Brandenburg University of Technology (BTU) Cottbus the differentially heated rotating annulus is a reference experiment of the DFG priority program 'MetStröm'. The 3D structure of the annulus flow field has been numerically simulated but, to our knowledge, has not been measured in the laboratory. In the present paper we use novel interpolation techniques to reconstruct the 3D annulus flow field from synchronous Particle Image Velocimetry (PIV) and Infrared Thermography (IRT) measurements. The PIV system is used to measure the horizontal velocity components at 40, 60, 80, 100, and 120 mm above the bottom. The uppermost level is thus 15 mm below the fluid's surface. The surface temperature is simultaneously measured by an infrared (IR) camera. The PIV and infrared cameras have been mounted above the annulus and they co-rotate with the annulus. From the PIV observations alone a coherent 3D picture of the flow cannot be constructed since the PIV measurements have been taken at different instants of time. Therefore a corresponding IR image has been recorded for each PIV measurement. These IR images can be used to reconstruct the correct phase of the measured velocity fields. Each IR and PIV image for which t>0 is rotated back to the position at t=0. Then all surface waves have the same phase. In contrast, the PIV velocity fields generally have different phases since they have been taken at different vertical levels. From these rotated fields, a 3D flow field can be reconstructed that is an approximation to the true 3D flow. The PIV measurements of the horizontal velocity fields do not line up on a nice grid. We therefore use a mesh-free reconstruction method based on radial basis functions (RBFs). Additionally, we employ a filtering strategy for dealing with the noise in the measured velocity fields.

Harlander, U.; Wright, G. B.; Egbers, C.

2012-04-01

249

A parallel algorithm for 3D particle tracking and Lagrangian trajectory reconstruction  

Science.gov (United States)

Particle-tracking methods are widely used in fluid mechanics and multi-target tracking research because of their unique ability to reconstruct long trajectories with high spatial and temporal resolution. Researchers have recently demonstrated 3D tracking of several objects in real time, but as the number of objects is increased, real-time tracking becomes impossible due to data transfer and processing bottlenecks. This problem may be solved by using parallel processing. In this paper, a parallel-processing framework has been developed based on frame decomposition and is programmed using the asynchronous object-oriented Charm++ paradigm. This framework can be a key step in achieving a scalable Lagrangian measurement system for particle-tracking velocimetry and may lead to real-time measurement capabilities. The parallel tracking algorithm was evaluated with three data sets including the particle image velocimetry standard 3D images data set #352, a uniform data set for optimal parallel performance and a computational-fluid-dynamics-generated non-uniform data set to test trajectory reconstruction accuracy, consistency with the sequential version and scalability to more than 500 processors. The algorithm showed strong scaling up to 512 processors and no inherent limits of scalability were seen. Ultimately, up to a 200-fold speedup is observed compared to the serial algorithm when 256 processors were used. The parallel algorithm is adaptable and could be easily modified to use any sequential tracking algorithm, which inputs frames of 3D particle location data and outputs particle trajectories.

Barker, Douglas; Lifflander, Jonathan; Arya, Anshu; Zhang, Yuanhui

2012-02-01

250

In-process 3D geometry reconstruction of objects produced by direct light projection  

DEFF Research Database (Denmark)

Additive manufacturing allows close-to unrestrained geometrical freedom in part design. The ability to manufacture geometries of such complexity is however limited by the difficulty of verifying the tolerances of these parts. Tolerances of features that are inaccessible with traditional measuring equipment such as coordinate measuring machines cannot be verified easily. This problem is addressed by developing an in-line reverse engineering and 3D reconstruction method that allows a true-to-scale reconstruction of a part being additively manufactured. In earlier works (Pedersen et al. 2010; Hansen et al. 2011), this method has shown its potential with 3D printing (3DP) and selective laser sintering additive manufacturing processes, where it is possible to directly capture the geometrical features of each individual layer during a build job using a digital camera. When considering the process of direct light projection (DLP), the possibility of directly capturing the geometrical features of the object during abuild job is limited by the specific machine design and the fact that photoactivated monomers often do not change optical characteristics in the polymerization process. Therefore, a variant of the previously tested and verified method has been implemented on DLP machine, where instead of capturing the geometrical features of the produced objects during the build job directly, these features are captured indirectly by capturing the reflection of the projected light projected during the build job. Test series were made, and a reconstruction of two octave spheres were produced and compared with the input CAD file and scans of the produced objects. The comparison showed a good correlation between the reconstructions and the scans considering the resolution of the images used for the reconstruction, and it was thereby concluded that the method has a promising potential as a verification method for DLP machines.

Andersen, Ulrik Vølcker; Pedersen, David Bue

2013-01-01

251

Evaluation of the 3-D radon transform algorithm for cone beam reconstruction  

Science.gov (United States)

The cone beam X-ray transform modelizes the measurements on new 3D medical imaging devices using 2D detectors, for instance X-ray transmission tomographs using image intensifiers or gamma-ray emission tomographs using convergent collimators. The most commonly used reconstruction algorithm performs cone beam back projection (FELDKAMP 1984). But it induces some distortions for objects far from the plane of the cone apex. We have established an exact formula between the cone beam X-ray transform and the first derivative of the 3D Radon transform (GRANGEAT 1987). It shows that the distortions are induced by the shadow zone in the Radon domain related to the planes which intersect the object but not the apex trajectory. In the Radon domain, it becomes possible to restore the missing information by interpolation. Then the reconstruction principle is to compute and to invert the first derivative of the Radon transform. In this communication, we compare these two algorithms on reconstructions performed on simulated acquisitions. We study the shape and level distortions along lines parallel to the rotation axis. We present an analysis of the axial and radial variations of the Modulation Transfer Function (MTF) and of their distortions. We conclude that the Radon transform algorithm provides a regularized solution to the distortions, with optimized computing time on modern scientific computers.

Grangeat, Pierre; Le Masson, Patrick; Melennec, Pierre; Sire, Pascal

1991-06-01

252

3D Reconstruction: Novel Method for Finding of Corresponding Points using Pseudo Colors  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with the reconstruction of spatial coordinates of an arbitrary point in a scene using two images scanned by a 3D camera or two displaced cameras. Calculations are based on the perspective geom-etry. Accurate determination of corresponding points is a fundamental step in this process. The usually used methods can have a problem with points, which lie in areas without sufficient contrast. This paper describes our proposed method based on the use of the relationship between the selected points and area feature points. The proposed method finds correspondence using a set of feature points found by SURF. An algorithm is proposed and described for quick removal of false correspondences, which could ruin the correct reconstruction. The new method, which makes use of pseudo color image representation (pseudo coloring has been proposed subsequently. By means of this method it is possible to significantly increase the color contrast of the surveyed image, and therefore add more information to find the correct correspondence. Reliability of the found correspondence can be verified by reconstruction of 3D position of selected points. Executed experiments confirm our assumptions

L. Bolecek

2013-04-01

253

Object-shape recognition and 3D reconstruction from tactile sensor images.  

Science.gov (United States)

This article presents a novel approach of edged and edgeless object-shape recognition and 3D reconstruction from gradient-based analysis of tactile images. We recognize an object's shape by visualizing a surface topology in our mind while grasping the object in our palm and also taking help from our past experience of exploring similar kind of objects. The proposed hybrid recognition strategy works in similar way in two stages. In the first stage, conventional object-shape recognition using linear support vector machine classifier is performed where regional descriptors features have been extracted from the tactile image. A 3D shape reconstruction is also performed depending upon the edged or edgeless objects classified from the tactile images. In the second stage, the hybrid recognition scheme utilizes the feature set comprising both the previously obtained regional descriptors features and some gradient-related information from the reconstructed object-shape image for the final recognition in corresponding four classes of objects viz. planar, one-edged object, two-edged object and cylindrical objects. The hybrid strategy achieves 97.62 % classification accuracy, while the conventional recognition scheme reaches only to 92.60 %. Moreover, the proposed algorithm has been proved to be less noise prone and more statistically robust. PMID:24469960

Khasnobish, Anwesha; Singh, Garima; Jati, Arindam; Konar, Amit; Tibarewala, D N

2014-04-01

254

Reconstructing 3D CAD models for simulation using imaging-based reverse engineering  

Science.gov (United States)

The purpose of this research is to investigate imaging-based methods to reconstruct 3D CAD models of real-world objects. The methodology uses structured lighting technologies such as coded-pattern projection and laser-based triangulation to sample 3D points on the surfaces of objects and then to reconstruct these surfaces from the dense point samples. This reverse engineering (RE) research presents reconstruction results for a military tire that is important to tire-soil simulations. The limitations of this approach are the current level of accuracy that imaging-based systems offer relative to more traditional CMM modeling systems. The benefit however is the potential for denser point samples and increased scanning speeds of objects, and with time, the imaging technologies should continue to improve to compete with CMM accuracy. This approach to RE should lead to high fidelity models of manufactured and prototyped components for comparison to the original CAD models and for simulation analysis. We focus this paper on the data collection and view registration problems within the RE pipeline.

Voisin, Sophie; Page, David; Koschan, Andreas; Abidi, Mongi

2006-06-01

255

Grating-based phase contrast tomosynthesis imaging: Proof-of-concept experimental studies  

Energy Technology Data Exchange (ETDEWEB)

Purpose: This paper concerns the feasibility of x-ray differential phase contrast (DPC) tomosynthesis imaging using a grating-based DPC benchtop experimental system, which is equipped with a commercial digital flat-panel detector and a medical-grade rotating-anode x-ray tube. An extensive system characterization was performed to quantify its imaging performance. Methods: The major components of the benchtop system include a diagnostic x-ray tube with a 1.0 mm nominal focal spot size, a flat-panel detector with 96 ?m pixel pitch, a sample stage that rotates within a limited angular span of ±30°, and a Talbot-Lau interferometer with three x-ray gratings. A total of 21 projection views acquired with 3° increments were used to reconstruct three sets of tomosynthetic image volumes, including the conventional absorption contrast tomosynthesis image volume (AC-tomo) reconstructed using the filtered-backprojection (FBP) algorithm with the ramp kernel, the phase contrast tomosynthesis image volume (PC-tomo) reconstructed using FBP with a Hilbert kernel, and the differential phase contrast tomosynthesis image volume (DPC-tomo) reconstructed using the shift-and-add algorithm. Three inhouse physical phantoms containing tissue-surrogate materials were used to characterize the signal linearity, the signal difference-to-noise ratio (SDNR), the three-dimensional noise power spectrum (3D NPS), and the through-plane artifact spread function (ASF). Results: While DPC-tomo highlights edges and interfaces in the image object, PC-tomo removes the differential nature of the DPC projection data and its pixel values are linearly related to the decrement of the real part of the x-ray refractive index. The SDNR values of polyoxymethylene in water and polystyrene in oil are 1.5 and 1.0, respectively, in AC-tomo, and the values were improved to 3.0 and 2.0, respectively, in PC-tomo. PC-tomo and AC-tomo demonstrate equivalent ASF, but their noise characteristics quantified by the 3D NPS were found to be different due to the difference in the tomosynthesis image reconstruction algorithms. Conclusions: It is feasible to simultaneously generate x-ray differential phase contrast, phase contrast, and absorption contrast tomosynthesis images using a grating-based data acquisition setup. The method shows promise in improving the visibility of several low-density materials and therefore merits further investigation.

Li, Ke; Ge, Yongshuai; Garrett, John; Bevins, Nicholas; Zambelli, Joseph [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 (United States); Chen, Guang-Hong, E-mail: gchen7@wisc.edu [Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, Wisconsin 53705 and Department of Radiology, University of Wisconsin-Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States)

2014-01-15

256

Grating-based phase contrast tomosynthesis imaging: Proof-of-concept experimental studies  

International Nuclear Information System (INIS)

Purpose: This paper concerns the feasibility of x-ray differential phase contrast (DPC) tomosynthesis imaging using a grating-based DPC benchtop experimental system, which is equipped with a commercial digital flat-panel detector and a medical-grade rotating-anode x-ray tube. An extensive system characterization was performed to quantify its imaging performance. Methods: The major components of the benchtop system include a diagnostic x-ray tube with a 1.0 mm nominal focal spot size, a flat-panel detector with 96 ?m pixel pitch, a sample stage that rotates within a limited angular span of ±30°, and a Talbot-Lau interferometer with three x-ray gratings. A total of 21 projection views acquired with 3° increments were used to reconstruct three sets of tomosynthetic image volumes, including the conventional absorption contrast tomosynthesis image volume (AC-tomo) reconstructed using the filtered-backprojection (FBP) algorithm with the ramp kernel, the phase contrast tomosynthesis image volume (PC-tomo) reconstructed using FBP with a Hilbert kernel, and the differential phase contrast tomosynthesis image volume (DPC-tomo) reconstructed using the shift-and-add algorithm. Three inhouse physical phantoms containing tissue-surrogate materials were used to characterize the signal linearity, the signal difference-to-noise ratio (SDNR), the three-dimensional noise power spectrum (3D NPS), and the through-plane artifact spread function (ASF). Results: While DPC-tomo highlights edges and interfaces in the image object, PC-tomo removes the differential nature of the DPC projection data and its pixel values are linearly related to the decrement of the real part of the x-ray refractive index. The SDNR values of polyoxymethylene in water and polystyrene in oil are 1.5 and 1.0, respectively, in AC-tomo, and the values were improved to 3.0 and 2.0, respectively, in PC-tomo. PC-tomo and AC-tomo demonstrate equivalent ASF, but their noise characteristics quantified by the 3D NPS were found to be different due to the difference in the tomosynthesis image reconstruction algorithms. Conclusions: It is feasible to simultaneously generate x-ray differential phase contrast, phase contrast, and absorption contrast tomosynthesis images using a grating-based data acquisition setup. The method shows promise in improving the visibility of several low-density materials and therefore merits further investigation

2014-01-01

257

Three-dimensional (3D) echocardiography: reconstruction algorithm and diagnostic performance of resulting images  

Science.gov (United States)

To date, 3D ultrasound imaging has been hampered by fractionated, job specific computer procedures, and the need for significant operator interaction. This paper presents our data processing algorithm for cardiac structure visualization from serial transesophageal echocardiographic (TEE) images. Major steps in the algorithm are: 1) image registration, 2) histogram operations for contrast enhancement, 3) noise and speckle filtering, 4) segmentation of composite color Doppler flow images, and 5) coordinate system conversion and interpolation. Three-dimensional reconstructions of clinical TEE examinations were compared to the corresponding serial 2D scans using receiver operator characteristics (ROC) analysis. The results demonstrated significantly better trade-off between diagnostic sensitivity and specificity in the 3D method when compared to the original 2D tomograms. We conclude that 3D echocaridography based on our algorithm is clinically feasible. Moreover, the ROC analysis on a limited group of patients indicated that 3D imaging facilitated comprehension of complex anatomic relationships and diagnostic capabilities of conventional 2D TEE echocardiography.

Belohlavek, Marek; Foley, David A.; Seward, James B.; Greenleaf, James F.

1994-09-01

258

A multiple-point statistics algorithm for 3D pore space reconstruction from 2D images  

Science.gov (United States)

Fluid flow behavior in a porous medium is a function of the geometry and topology of its pore space. The construction of a three dimensional pore space model of a porous medium is therefore an important first step in characterizing the medium and predicting its flow properties. A stochastic technique for reconstruction of the 3D pore structure of unstructured random porous media from a 2D thin section training image is presented. The proposed technique relies on successive 2D multiple point statistics simulations coupled to a multi-scale conditioning data extraction procedure. The Single Normal Equation Simulation Algorithm (SNESIM), originally developed as a tool for reproduction of long-range, curvilinear features of geological structures, serves as the simulation engine. Various validating criteria such as marginal distributions of pore and grain, directional variograms, multiple-point connectivity curves, single phase effective permeability and two phase relative permeability calculations are used to analyze the results. The method is tested on a sample of Berea sandstone for which a 3D micro-CT scanning image is available. The results confirm that the equi-probable 3D realizations obtained preserve the typical patterns of the pore space that exist in thin sections, reproduce the long-range connectivities, capture the characteristics of anisotropy in both horizontal and vertical directions and have single and two phase flow characteristics consistent with those of the measured 3D micro-CT image.

Hajizadeh, Alireza; Safekordi, Aliakbar; Farhadpour, Farhad A.

2011-10-01

259

Approximation of a foreign object using x-rays, reference photographs and 3D reconstruction techniques.  

Science.gov (United States)

This case study describes how a 3D animation was created to approximate the depth and angle of a foreign object (metal bar) that had become embedded into a patient's head. A pre-operative CT scan was not available as the patient could not fit though the CT scanner, therefore a post surgical CT scan, x-ray and photographic images were used. A surface render was made of the skull and imported into Blender (a 3D animation application). The metal bar was not available, however images of a similar object that was retrieved from the scene by the ambulance crew were used to recreate a 3D model. The x-ray images were then imported into Blender and used as background images in order to align the skull reconstruction and metal bar at the correct depth/angle. A 3D animation was then created to fully illustrate the angle and depth of the iron bar in the skull. PMID:24206011

Briggs, Matt; Shanmugam, Mohan

2013-12-01

260

3D Reconstruction of Coronal Loops by the Principal Component Analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Knowing the three dimensional structure of plasma filaments in the uppermost part of the solar atmosphere, known as coronal loops, and especially their length, is an important parameter in the wave-based diagnostics of this part of the Sun. The combination of observations of the Sun from different points of observations in space, thanks to the most recent missions, including the Solar Dynamics Observatory (SDO and the Solar TErrestrial RElations Observatory (STEREO, allows us to infer information about the geometrical shape of coronal loops in 3D space. Here, we propose a new method to reconstruct the loop shape starting from stereoscopically determined 3D points, which sample the loop length, by principal component analysis. This method is shown to retrieve in an easy way the main parameters that define the loop, e.g., the minor and major axes, the loop plane, the azimuthal and inclination angles, for the special case of a coplanar loop.

Erwin Verwichte

2013-10-01

 
 
 
 
261

Advanced algorithms for identifying targets from a three-dimensional reconstruction of sparse 3D ladar data  

Science.gov (United States)

There is a considerable interest in the development of new optical imaging systems that are able to give threedimensional images. Potential applications range across medical imaging, surveillance and robotic vision. Identifying targets or objects concealed by foliage or camouflage is a critical requirement for operations in public safety, law enforcement and defense. The most promising techniques for these tasks are 3D laser imaging techniques. Their principles are to use movable light sources and detectors to collect information on laser scattering and to reconstruct the 3D objects of interest. 3D reconstruction algorithm is a major component in these optical systems for identification of camouflaged objects. But 3D reconstruction must take into account sparse collected data i.e. concealed objects and reconstruction algorithms must solve a complex multi-parameter inverse problem. Therefore the inverse problem of recovering the surface three-dimensional shape function from intensity data is more challenging. The objective of our paper is to present a new algorithmic approach for the generation of 3D surface data from 3D point clouds corresponding to reconstruction algorithm. This algorithmic approach is based on research of automatic minimization of an energy function associated with a sparse structure of 3D points. The role of this type of algorithmic data-driving process is to complete the incomplete 3D image at satisfactory levels for reliable identification of concealed objects.

Berechet, Ion; Berginc, Gérard

2011-09-01

262

Portable and accurate 3D scanner for breast implant design and reconstructive plastic surgery  

Science.gov (United States)

In order to evaluate the proper breast implant, the surgeon relies on a standard set of measurements manually taken on the subject. This approach does not allow to obtain an accurate reconstruction of the breast shape and asymmetries can easily arise after surgery. The purpose of this work is to present a method which can help the surgeon in the choice of the shape and dimensions of a prosthesis allowing for a perfect symmetry between the prosthesis and the controlateral breast and can be used as a 3D visual feedback in plastic surgery.

Rigotti, Camilla; Borghese, Nunzio A.; Ferrari, Stefano; Baroni, Guido; Ferrigno, Giancarlo

1998-06-01

263

Automatic Reconstruction of Unstructured 3D data : Combining Medial Axis and Implicit Surfaces  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a new method that combines a medial axis and implicit surfaces in order to reconstruct a 3D solid from an unstructured set of points scattered on the object's surface. The representation produced is based on iso-surfaces generated by skeletons, and is a particularly compact way of defining a smooth free-form solid. The method is based on the minimisation of an energy representing a "distance" between the set of data points and the iso-surface, resembling previous reserach....

Bittar, Eric; Tsingos, Nicolas; Cani, Marie-paule

1995-01-01

264

Molecular-Frame 3D Photoelectron Momentum Distributions by Tomographic Reconstruction  

DEFF Research Database (Denmark)

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 momentum distribution is obtained by tomographic reconstruction from all 90 projections. It reveals an anisotropic electron distribution, angularly shifted in the polarization plane, that is not accessible by the 2D momentum images. Our theoretical analysis shows that the magnitude of the angular shift is very sensitive to the exact form of the laser-modified molecular potential.

Maurer, Jochen; Dimitrovski, Darko

2012-01-01

265

3D CAD model reconstruction of a human femur from MRI images  

Directory of Open Access Journals (Sweden)

Full Text Available Medical practice and life sciences take full advantage of progress in engineering disciplines, in particular the computer assisted placement technique in hip surgery. This paper describes the three dimensional model reconstruction of human femur from MRI images. The developed program enables to obtain digital shape of 3D femur recognized by all CAD software and allows an accurate placement of the femoral component. This technic provides precise measurement of implant alignment during hip resurfacing or total hip arthroplasty, thereby reducing the risk of component mal-positioning and femoral neck notching.

Benaissa EL FAHIME

2013-05-01

266

The NOG Sample: 3D Reconstruction of the Real-Space Density Field  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We discuss the real-space reconstruction of the optical galaxy density field in the local Universe (cz < 6000 km/s) as derived from the 7076 galaxies of the Nearby Optical Galaxy (NOG) sample (see Giuricin et al. 1999 in the same volume). NOG is the currently best approximation to a homogeneous all-sky 3D optically selected galaxy sample that probes in great detail volumes of cosmological interest. Our final goal is to construct a reliable, robust and unbiased field of densi...

Marinoni, C.; Giuricin, G.; Ceriani, L.

1999-01-01

267

3D Magnetic Resonance Imaging of the Human Brain - Novel Radial Sampling, Filtering and Reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have suggested a novel method PRESTO-CAN including radial sampling, filtering and reconstruction of k-space data for 3D-plus-time resolved MRI. The angular increment of the profiles was based on the golden ratio, but the number of angular positions N was locked to be a prime number which guaranteed fix angle positions.The time resolution increased dramatically when the pro-files were partly removed from the k-space using the hourglass filter.We aim for utilizing the MRI-data for fMRI, wher...

Magnusson, Maria; Dahlqvist Leinhard, Olof; Brynolfsson, Patrik; Thyr, Per; Lundberg, Peter

2010-01-01

268

3D object reconstruction from Swissranger sensor data using a spring-mass model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We register close-range depth images of objects using a Swissranger sensor and apply a spring-mass model for 3D object reconstruction. The Swissranger sensor delivers depth images in real time which have, compared with other types of sensors, such as laser scanners, a lower resolution and are af?icted with larger uncertainties. To reduce noise and remove outliers in the data, we treat the point cloud as a system of interacting masses connected via elastic forces. We investigate two models, ...

Dellen, Babette; Alenya? Ribas, Guillem; Foix Salmero?n, Sergi; Torras Geni?s, Carme

2009-01-01

269

Novel Calibration and Lens Distortion Correction of 3D Reconstruction Systems  

International Nuclear Information System (INIS)

A novel calibration and lens distortion correction of 3D reconstruction systems is introduced in this paper. Assuming zero distortion at the center of image, the parameter calibration and lens distortion correction of CCD camera and DLP projector is separated with the points in center and all the rest points. Furthermore, identification and correspondence of the interest points is done automatically because of the designed target with standard circles and multicolor code of pseudo-random array during the calibration. The experiments show that it is a fast and convenient method to carry out the calibration for lens distortion

2006-10-01

270

Improved 3D reconstruction in smart-room environments using ToF imaging  

DEFF Research Database (Denmark)

This paper presents the use of Time-of-Flight (ToF) cameras in smart-rooms and how this leads to improved results in segmenting the people in the room from the background and consequently better 3D reconstruction of foreground objects. A calibrated rig consisting of one Swissranger SR3100 Time-of-Flight range camera and a high resolution standard CCD camera is set in a smart-room containing five other standard cameras. A probabilistic background model is used to segment each view and a shape from silhouette volume is reconstructed. It is shown that the presence of the range camera gives ways of eliminating regional artifacts and therefore creating a more robust input for higher level applications such as people tracking or human motion analysis.

Guðmundsson, Sigurjón Árni; Pardas, Montse

2010-01-01

271

Simulation and reconstruction of photon patterns in the PANDA 3D Disc DIRC  

International Nuclear Information System (INIS)

The PANDA Disc DIRC is a novel type of Cherenkov detector, being developed to improve the charged particle identification of the upcoming PANDA experiment at the future FAIR facility. The detector has to cover the endcap region of the target spectrometer, resulting in a geometry that by now has never been applied to a DIRC detector. Additional complications are implied by tight space constraints at the foreseen position, interaction rates of 20 MHz up to 50 MHz and the experiments trigger-less readout scheme. To cope with the lack of experience, the development of detector concepts is driven by the development of computer simulations and dedicated reconstruction methods. The performance analysis of a preceding detector concept, presented at the DIRC workshop in 2009, showed several weaknesses which have been eliminated by revising the detector design. This publication summarizes the current status of the software, the reconstruction method and resulting detector performance of the improved design: the PANDA 3D Disc DIRC.

2012-01-01

272

High resolution 3D image reconstruction in laminar optical tomography based on compressive sensing  

Science.gov (United States)

Laminar optical tomography (LOT) combines the advantages of diffuse optical tomography image reconstruction and a microscopy-based setup to allow non-contact imaging at depth up to a few millimeters. However, LOT image reconstruction paradigm is inherently an ill-posed and computationally expensive inverse problem. Herein, we cast the LOT inverse problem in the compressive sensing (CS) framework to exploit the sparsity of the fluorophore yield in the image domain and to address the ill-posedness of the LOT inverse problem. We apply this new approach to thick tissue engineering applications. We demonstrate the enhanced resolution of our method in 3-D numerical simulations of anatomically accurate microvasculature and using real data obtained from phantom experiments. Furthermore, CS is shown to be more robust against the reduction of measurements in comparison to the classic methods for such application. Potential benefits and shortcomings of the CS approach in the context of LOT are discussed.

Yang, Fugang; Ozturk, Mehmet S.; Cong, Wenxiang; Wang, Ge; Intes, Xavier

2014-02-01

273

Reconstruction of 3D Human Facial Images Using Partial Differential Equations  

Directory of Open Access Journals (Sweden)

Full Text Available

One of the challenging problems in geometric modeling and computer graphics is the construction of realistic human facial geometry. Such geometry are essential for a wide range of applications, such as 3D face recognition, virtual reality applications, facial expression simulation and computer based plastic surgery application. This paper addresses a method for the construction of 3D geometry of human faces based on the use of Elliptic Partial Differential Equations (PDE. Here the geometry corresponding to a human face is treated as a set of surface patches, whereby each surface patch is represented using four boundary curves in the 3-space that formulate the appropriate boundary conditions for the chosen PDE. These boundary curves are extracted automatically using 3D data of human faces obtained using a 3D scanner. The solution of the PDE generates a continuous single surface patch describing the geometry of the original scanned data. In this study, through a number of experimental verifications we have shown the efficiency of the PDE based method for 3D facial surface reconstruction using scan data. In addition to this, we also show that our approach provides an efficient way of facial representation using a small set of parameters that could be utilized for efficient facial data storage and verification purposes.

Hassan Ugail

2007-10-01

274

Out-of-plane photon compensation for 3-D SPECT image reconstruction with generalized matrix inverses  

International Nuclear Information System (INIS)

A computationally efficient 3-D image reconstruction method which compensates for detected out-of-plane photons has been developed for SPECT image reconstruction with generalized matrix inverses (GMI). Fully 3-D image reconstruction is approximated by a series of coupled 2-D image reconstructions for projection data acquired with parallel hole collimators, significantly reducing computer memory requirements. In this method, projection data are compensated for detected scattered photons using dual energy window scatter subtraction (Step 1). An initial source activity estimate in each transverse plane is then made using line source response functions in the system matrix (Step 2). With these activity estimates the contributions of out-of-plane unscattered photons are modeled and subtracted from the projection data, and an updated source activity estimate is computed (Step 3). For noise-free projection data from a Monte Carlo simulated myocardial perfusion study, lesion contrast increases and activity spillover from the myocardium into the adjacent cardiac blood pool is reduced. For projection data with Poisson noise, activity estimates from Step 3 are inferior to those from Step 2. One reason is that the relative noise level of the projection data is substantially increased by subtracting the estimated out-of-plane contribution. The Step 3 activity estimation is also sensitive to the source activity distribution used for out-of-plane unscattered photon compensation. Though the out-of-plane compensation technique of Step 3 provides some benefit for noise-free projection data, this study suggests that it may not be well-suited for practical application to count-limited clinical SPECT studies

1994-12-01

275

GPS tomography. Validation of reconstructed 3-D humidity fields with radiosonde profiles  

Energy Technology Data Exchange (ETDEWEB)

Water vapor plays an important role in meteorological applications; GeoForschungsZentrum (GFZ) therefore developed a tomographic system to derive 3-D distributions of the tropospheric water vapor above Germany using GPS data from about 300 ground stations. Input data for the tomographic reconstructions are generated by the Earth Parameter and Orbit determination System (EPOS) software of the GFZ, which provides zenith total delay (ZTD), integrated water vapor (IWV) and slant total delay (STD) data operationally with a temporal resolution of 2.5 min (STD) and 15 min (ZTD, IWV). The water vapor distribution in the atmosphere is derived by tomographic reconstruction techniques. The quality of the solution is dependent on many factors such as the spatial coverage of the atmosphere with slant paths, the spatial distribution of their intersections and the accuracy of the input observations. Independent observations are required to validate the tomographic reconstructions and to get precise information on the accuracy of the derived 3-D water vapor fields. To determine the quality of the GPS tomography, more than 8000 vertical water vapor profiles at 13 German radiosonde stations were used for the comparison. The radiosondes were launched twice a day (at 00:00 UTC and 12:00 UTC) in 2007. In this paper, parameters of the entire profiles such as the wet refractivity, and the zenith wet delay have been compared. Before the validation the temporal and spatial distribution of the slant paths, serving as a basis for tomographic reconstruction, as well as their angular distribution were studied. The mean wet refractivity differences between tomography and radiosonde data for all points vary from -1.3 to 0.3, and the root mean square is within the range of 6.5-9. About 32% of 6803 profiles match well, 23% match badly and 45% are difficult to classify as they match only in parts.

Shangguan, M.; Bender, M.; Ramatschi, M.; Dick, G.; Wickert, J. [Helmholtz Centre Potsdam, German Research Centre for Geosciences (GFZ), Potsdam (Germany); Raabe, A. [Leipzig Institute for Meteorology (LIM), Leipzig (Germany); Galas, R. [Technische Univ. Berlin (Germany). Dept. for Geodesy and Geoinformation Sciences

2013-11-01

276

Compressed sensing reconstruction of undersampled 3D NOESY spectra: application to large membrane proteins  

Energy Technology Data Exchange (ETDEWEB)

Central to structural studies of biomolecules are multidimensional experiments. These are lengthy to record due to the requirement to sample the full Nyquist grid. Time savings can be achieved through undersampling the indirectly-detected dimensions combined with non-Fourier Transform (FT) processing, provided the experimental signal-to-noise ratio is sufficient. Alternatively, resolution and signal-to-noise can be improved within a given experiment time. However, non-FT based reconstruction of undersampled spectra that encompass a wide signal dynamic range is strongly impeded by the non-linear behaviour of many methods, which further compromises the detection of weak peaks. Here we show, through an application to a larger {alpha}-helical membrane protein under crowded spectral conditions, the potential use of compressed sensing (CS) l{sub 1}-norm minimization to reconstruct undersampled 3D NOESY spectra. Substantial signal overlap and low sensitivity make this a demanding application, which strongly benefits from the improvements in signal-to-noise and resolution per unit time achieved through the undersampling approach. The quality of the reconstructions is assessed under varying conditions. We show that the CS approach is robust to noise and, despite significant spectral overlap, is able to reconstruct high quality spectra from data sets recorded in far less than half the amount of time required for regular sampling.

Bostock, Mark J. [University of Cambridge, Department of Biochemistry (United Kingdom); Holland, Daniel J. [University of Cambridge, Department of Chemical Engineering and Biotechnology (United Kingdom); Nietlispach, Daniel, E-mail: dn206@cam.ac.uk [University of Cambridge, Department of Biochemistry (United Kingdom)

2012-09-15

277

Enhanced 3D PET OSEM reconstruction using inter-update Metz filtering  

International Nuclear Information System (INIS)

We present an enhancement of the OSEM (ordered set expectation maximization) algorithm for 3D PET reconstruction, which we call the inter-update Metz filtered OSEM (IMF-OSEM). The IMF-OSEM algorithm incorporates filtering action into the image updating process in order to improve the quality of the reconstruction. With this technique, the multiplicative correction image - ordinarily used to update image estimates in plain OSEM - is applied to a Metz-filtered version of the image estimate at certain intervals. In addition, we present a software implementation that employs several high-speed features to accelerate reconstruction. These features include, firstly, forward and back projection functions which make full use of symmetry as well as a fast incremental computation technique. Secondly, the software has the capability of running in parallel mode on several processors. The parallelization approach employed yields a significant speed-up, which is nearly independent of the amount of data. Together, these features lead to reasonable reconstruction times even when using large image arrays and non-axially compressed projection data. The performance of IMF-OSEM was tested on phantom data acquired on the GE Advance scanner. Our results demonstrate that an appropriate choice of Metz filter parameters can improve the contrast-noise balance of certain regions of interest relative to both plain and post-filtered OSEM, and to the GE commercial reprojection algorithm software. (author)

2000-08-01

278

Towards the reconstruction of 3D orientation information from direction-sensitive X-ray projections  

International Nuclear Information System (INIS)

For medical in vivo applications the resolution of a computed tomography (CT) scan is limited by the acceptable patient received dose. Thus it does not allow to image microstructures in the body. Novel X-ray contrast mechanisms provide two additional signal channels, phase contrast and dark-field contrast. In this study we report on our progress to use the dark-field signal to gain micro-structural information by reconstructing a tensor field describing the local sample scattering power. For that purpose we developed an experimental setup composed of an X-ray tube, a Talbot Lau interferometer, an Euler cradle to orient the sample and a detector. This setup allows a direct measurement of the sample scattering strength in all directions. The reconstruction of several test samples is done using filtered back-projection or the algebraic reconstruction technique. The definition of the physical model behind the reconstructed quantity is obtained from a second ansatz by using 3D density map (micro-CT) data as an input to a computer simulation of the whole setup. We consider this project important for diagnostic improvements in the case of bone pathologies. (orig.)

2011-07-11

279

3D Monte Carlo Reconstruction and Characterization of LiCoO2 Cathode  

Directory of Open Access Journals (Sweden)

Full Text Available Reconstruction and characterization of the porous composite electrode via experimental and numerical approaches are the basis and prerequisite of pore-scale modeling. The Monte Carlo approach was employed to reconstruct the LiCoO2 cathode of a Li-ion battery. The reconstructed electrode resolves sub-micrometer microstructure, thus evidently distinguishing the three individual phases: LiCoO2 as active material, pores (electrolyte, and additives. An extensive characterization was subsequently performed to calculate some important structural parameters and transport properties, including the geometrical connectivity and the specific surface area, etc. Particularly, a self-developed D3Q15 LB (Lattice Boltzmann model was used to calculate the effective thermal (or electric conductivity and the effective species diffusivity in electrolyte (or solid phase, and the tortuosity of an individual phase. The reconstructed 3D microstructure is consistent with the real cathode microstructure concerning several important statistical features including porosity, volume fraction of each phase, and two-point correlation functions etc. LB model predictions indicate that the effective transport coefficients are closely related to the micro-morphology in electrodes.

WU Wei, JIANG Fang-Ming, CHEN Zhi, WANG Ying, ZHAO Feng-Gang, ZENG Yu-Qun

2013-11-01

280

FST-based Reconstruction of 3D-models from Non-Uniformly Sampled Datasets on the Sphere  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a new method for reconstruction of star-shaped 3D surfaces from scattered datasets, where such surfaces are considered as signals living in the space of square integrable functions on the unit sphere. We first propose a generalization of the Fourier transform on the sphere. A practical reconstruction method is then presented, which interpolates a spherical signal on an equiangular grid, from non-uniformly sampled dataset representing a 3D point cloud. The experiments show ...

Tosic, I.; Frossard, P.

2006-01-01

 
 
 
 
281

Stereo-vision and 3D reconstruction for nuclear mobile robots  

International Nuclear Information System (INIS)

In order to perceive the geometric structure of the surrounding environment of a mobile robot, a 3D reconstruction system has been developed. Its main purpose is to provide geometric information to an operator who has to telepilot the vehicle in a nuclear power plant. The perception system is split into two parts: the vision part and the map building part. Vision is enhanced with a fusion process that rejects bas samples over space and time. The vision is based on trinocular stereo-vision which provides a range image of the image contours. It performs line contour correlation on horizontal image pairs and vertical image pairs. The results are then spatially fused in order to have one distance image, with a quality independent of the orientation of the contour. The 3D reconstruction is based on grid-based sensor fusion. As the robot moves and perceives its environment, distance data is accumulated onto a regular square grid, taking into account the uncertainty of the sensor through a sensor measurement statistical model. This approach allows both spatial and temporal fusion. Uncertainty due to sensor position and robot position is also integrated into the absolute local map. This system is modular and generic and can integrate 2D laser range finder and active vision. (author)

1991-01-01

282

Reimaging Past Worlds: Issues and Challenges in the Use of 3D Graphics for Historical Reconstructions  

Directory of Open Access Journals (Sweden)

Full Text Available 3D computer rendering technology allows researchers to present their scenes with fully navigable and interactive virtual recreations of past environments. Completing an accurate and effective historical CG reconstruction is a complex process, in which researchers must carefully balance a number of important and independent factors. At the research stage, creators must determine whether the product will be directly illustrative or more broadly interpretive, and how they will evaluate evidence from sources of difference media. Once they begin designing the reconstruction, the level of visual detail that creators select is crucial. High detail projects display greater realism, but are more expensive and time consuming. Conversely lower detail scenes are better suited for multiple media formats, and are most efficient, customizable, and cost-effective. A scholar’s consideration of these issues will help determine the number of collaborators and software necessary, as well as the project’s output format. 3D computer graphics offer an unparalleled opportunity to present visions of the past to the public, but only thoughtfully planned projects will realize their full potential.

James Coltrain

2009-07-01

283

Reconstructing 3D coastal cliffs from airborne oblique photographs without ground control points  

Science.gov (United States)

Coastal cliff collapse hazard assessment requires measuring cliff face topography at regular intervals. Terrestrial laser scanner techniques have proven useful so far but are expensive to use either through purchasing the equipment or through survey subcontracting. In addition, terrestrial laser surveys take time which is sometimes incompatible with the time during with the beach is accessible at low-tide. By comparison, structure from motion techniques (SFM) are much less costly to implement, and if airborne, acquisition of several kilometers of coastline can be done in a matter of minutes. In this paper, the potential of GPS-tagged oblique airborne photographs and SFM techniques is examined to reconstruct chalk cliff dense 3D point clouds without Ground Control Points (GCP). The focus is put on comparing the relative 3D point of views reconstructed by Visual SFM with their synchronous Solmeta Geotagger Pro2 GPS locations using robust estimators. With a set of 568 oblique photos, shot from the open door of an airplane with a triplet of synchronized Nikon D7000, GPS and SFM-determined view point coordinates converge to X: ±31.5 m; Y: ±39.7 m; Z: ±13.0 m (LE66). Uncertainty in GPS position affects the model scale, angular attitude of the reference frame (the shoreline ends up tilted by 2°) and absolute positioning. Ground Control Points cannot be avoided to orient such models.

Dewez, T. J. B.

2014-05-01

284

3-D kinematics and neuromuscular signals' integration for post ACL reconstruction recovery assessment.  

Science.gov (United States)

An intelligent recovery classification and monitoring system (IRCMS) for post Anterior Cruciate Ligament (ACL) reconstruction has been developed in this study. This system provides an objective assessment and monitoring of the rehabilitation progress by integrating 3-D kinematics and neuromuscular signals recorded through wearable motion and electromyography sensors, respectively. The data from a group of healthy and ACL reconstructed subjects were collected for normal/brisk walking (4-6km/h) and single leg balance (eyes open and eyes closed) testing activities. Fuzzy clustering and fuzzy nearest neighbor methods have been used to classify the collected data into different groups for each activity. The classification accuracy of the system is found to be 94.49% for 4 km/h walking speed, 95.41% for 5 km/h walking speed, 96.00% for 6 km/h walking speed, 94.44% for single leg balance testing with eyes open and 95.83% for single leg balance testing with eyes closed. The recovery status of a subject is evaluated based on different activities assessed and the overall assessment is done using Choquet integral fusion technique. Further, biofeedback mechanism has been developed using a visual monitoring system which provides the variations in strength/activation of knee flexors/extensors and 3-D joint kinematics. This integrated system can be used as an assistive tool by sports trainers, coaches and clinicians for monitoring overall progress of athletes' rehabilitation and classifying their recovery stage for multiple activities. PMID:24111411

Senanayake, S M N Arosha; Malik, Owais A; Iskandar, Mohammad; Zaheer, Danish

2013-01-01

285

A Reconstruction Approach for Imaging in 3D Cone Beam Vector Field Tomography  

Directory of Open Access Journals (Sweden)

Full Text Available 3D cone beam vector field tomography (VFT aims for reconstructing and visualizing the velocity field of a moving fluid by measuring line integrals of projections of the vector field. The data are obtained by ultrasound measurements along a scanning curve which surrounds the object. From a mathematical point of view, we have to deal with the inversion of the vectorial cone beam transform. Since the vectorial cone beam transform of any gradient vector field with compact support is identically equal to zero, we can only hope to reconstruct the solenoidal part of an arbitrary vector field. In this paper we will at first summarize important properties of the cone beam transform for three-dimensional solenoidal vector fields and then propose a solution approach based on the method of approximate inverse. In this context, we intensively make use of results from scalar 3D computerized tomography. The findings presented in the paper will continuously be illustrated by pictures from first numerical experiments done with exact, simulated data.

A. K. Louis

2009-02-01

286

Applicability of 3D-CT facial reconstruction for forensic individual identification / Aplicabilidade da reconstrução facial em 3D-TC para identificação individual forense  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese A tomografia computadorizada (TC) tem sido utilizada em diversas áreas clínicas da Odontologia; utilizam-se tanto seus cortes originais quanto as reconstruções em duas e três dimensões (2D-TC e 3D-TC). O presente estudo propõe avaliar a precisão das medidas lineares realizadas na 3D-TC, utilizando a [...] craniometria, para fins de identificação individual na Odontologia Forense. Cinco cabeças de cadáveres foram submetidas a tomografia computadorizada em espiral por meio de cortes axiais e reconstruções em 3D-TC foram obtidas por meio da técnica de volume, utilizando recursos da computação gráfica. Medidas craniométricas (n = 10) foram determinadas nas imagens em 3D-TC por dois examinadores independentemente, duas vezes cada um, e uma análise de erro padrão percentual das medidas intra- e inter-examinadores foi realizada. Os resultados demonstraram um erro padrão percentual baixo apresentado por essas medidas, variando entre 0,85% e 3,09%. Em conclusão, as medidas lineares obtidas nas estruturas ósseas e tegumentares foram consideradas precisas em 3D-TC, com alta qualidade e resolução de imagem. Abstract in english Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for indi [...] vidual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) craniometric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution.

Sara dos Santos, Rocha; Dalton Luiz de Paula, Ramos; Marcelo de Gusmão Paraíso, Cavalcanti.

287

Applicability of 3D-CT facial reconstruction for forensic individual identification Aplicabilidade da reconstrução facial em 3D-TC para identificação individual forense  

Directory of Open Access Journals (Sweden)

Full Text Available Computed tomography (CT is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT. The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10 craniometric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution.A tomografia computadorizada (TC tem sido utilizada em diversas áreas clínicas da Odontologia; utilizam-se tanto seus cortes originais quanto as reconstruções em duas e três dimensões (2D-TC e 3D-TC. O presente estudo propõe avaliar a precisão das medidas lineares realizadas na 3D-TC, utilizando a craniometria, para fins de identificação individual na Odontologia Forense. Cinco cabeças de cadáveres foram submetidas a tomografia computadorizada em espiral por meio de cortes axiais e reconstruções em 3D-TC foram obtidas por meio da técnica de volume, utilizando recursos da computação gráfica. Medidas craniométricas (n = 10 foram determinadas nas imagens em 3D-TC por dois examinadores independentemente, duas vezes cada um, e uma análise de erro padrão percentual das medidas intra- e inter-examinadores foi realizada. Os resultados demonstraram um erro padrão percentual baixo apresentado por essas medidas, variando entre 0,85% e 3,09%. Em conclusão, as medidas lineares obtidas nas estruturas ósseas e tegumentares foram consideradas precisas em 3D-TC, com alta qualidade e resolução de imagem.

Sara dos Santos Rocha

2003-03-01

288

Large-scale reconstruction of 3D structures of human chromosomes from chromosomal contact data.  

Science.gov (United States)

Chromosomes are not positioned randomly within a nucleus, but instead, they adopt preferred spatial conformations to facilitate necessary long-range gene-gene interactions and regulations. Thus, obtaining the 3D shape of chromosomes of a genome is critical for understanding how the genome folds, functions and how its genes interact and are regulated. Here, we describe a method to reconstruct preferred 3D structures of individual chromosomes of the human genome from chromosomal contact data generated by the Hi-C chromosome conformation capturing technique. A novel parameterized objective function was designed for modeling chromosome structures, which was optimized by a gradient descent method to generate chromosomal structural models that could satisfy as many intra-chromosomal contacts as possible. We applied the objective function and the corresponding optimization method to two Hi-C chromosomal data sets of both a healthy and a cancerous human B-cell to construct 3D models of individual chromosomes at resolutions of 1 MB and 200 KB, respectively. The parameters used with the method were calibrated according to an independent fluorescence in situ hybridization experimental data. The structural models generated by our method could satisfy a high percentage of contacts (pairs of loci in interaction) and non-contacts (pairs of loci not in interaction) and were compatible with the known two-compartment organization of human chromatin structures. Furthermore, structural models generated at different resolutions and from randomly permuted data sets were consistent. PMID:24465004

Trieu, Tuan; Cheng, Jianlin

2014-04-01

289

Large-scale reconstruction of 3D structures of human chromosomes from chromosomal contact data  

Science.gov (United States)

Chromosomes are not positioned randomly within a nucleus, but instead, they adopt preferred spatial conformations to facilitate necessary long-range gene–gene interactions and regulations. Thus, obtaining the 3D shape of chromosomes of a genome is critical for understanding how the genome folds, functions and how its genes interact and are regulated. Here, we describe a method to reconstruct preferred 3D structures of individual chromosomes of the human genome from chromosomal contact data generated by the Hi-C chromosome conformation capturing technique. A novel parameterized objective function was designed for modeling chromosome structures, which was optimized by a gradient descent method to generate chromosomal structural models that could satisfy as many intra-chromosomal contacts as possible. We applied the objective function and the corresponding optimization method to two Hi-C chromosomal data sets of both a healthy and a cancerous human B-cell to construct 3D models of individual chromosomes at resolutions of 1 MB and 200 KB, respectively. The parameters used with the method were calibrated according to an independent fluorescence in situ hybridization experimental data. The structural models generated by our method could satisfy a high percentage of contacts (pairs of loci in interaction) and non-contacts (pairs of loci not in interaction) and were compatible with the known two-compartment organization of human chromatin structures. Furthermore, structural models generated at different resolutions and from randomly permuted data sets were consistent.

Trieu, Tuan; Cheng, Jianlin

2014-01-01

290

A System for an Accurate 3D Reconstruction in Video Endoscopy Capsule  

Directory of Open Access Journals (Sweden)

Full Text Available Since few years, the gastroenterologic examinations could have been realised by wireless video capsules. Although the images make it possible to analyse some diseases, the diagnosis could be improved by the use of the 3D Imaging techniques implemented in the video capsule. The work presented here is related to Cyclope, an embedded active vision system that is able to give in real time both 3D information and texture. The challenge is to realise this integrated sensor with constraints on size, consumption, and computational resources with inherent limitation of video capsule. In this paper, we present the hardware and software development of a wireless multispectral vision sensor which allows to transmit, a 3D reconstruction of a scene in realtime. multispectral acquisitions grab both texture and IR pattern images at least at 25 frames/s separately. The different Intellectual Properties designed allow to compute specifics algorithms in real time while keeping accuracy computation. We present experimental results with the realization of a large-scale demonstrator using an SOPC prototyping board.

Granado Bertrand

2009-01-01

291

An Analytical Review of Stereovision Techniques to Reconstruct 3D Coordinates  

Directory of Open Access Journals (Sweden)

Full Text Available Stereovision based on 3D environment reconstruction provides a true picture of real world situations for detection of objects’ locations. This approach has specific use in the scenarios like identifying traffic jams on the roads, locating curves and bends on the roads, finding obstacles in the construction sites, etc. This paper describes different methods used in stereovision to detect images like use of trinocular stereovision, calculating correlation between left and right contours for achieving accuracy, use of prior information with intrinsic and extrinsic parameters, detection of side lane and 3D points of guardrails and fences, use of dense stereovision information, especially in urban environment. The paper also discusses Forward Collision Detection method that uses Elevation Map with Dense Stereovision, tracking of multiple objects using two-level approach and building an enhanced grid that involves obstacle cells. Hybrid dense stereo engine, which is used in urban detection scenarios is also discussed in the paper along with a solution of lane estimation in different situations using particle filtering method. Pattern matching using 3D image for pedestrian detection and lane estimation based on the particle filtering with greyscale images are also explored. The use of the rectangular digital elevation map for transforming stereo based information and the methodology used to enhance the sub pixel accuracy are also part of the paper.

Raheel Ahmed

2013-06-01

292

3D endobronchial ultrasound reconstruction and analysis for multimodal image-guided bronchoscopy  

Science.gov (United States)

State-of-the-art image-guided intervention (IGI) systems for lung-cancer management draw upon high-resolution three-dimensional multi-detector computed-tomography (MDCT) images and bronchoscopic video. An MDCT scan provides a high-resolution three-dimensional (3D) image of the chest that is used for preoperative procedure planning, while bronchoscopy gives live intraoperative video of the endobronchial airway tree structure. However, because neither source provides live extraluminal information on suspect nodules or lymph nodes, endobronchial ultrasound (EBUS) is often introduced during a procedure. Unfortunately, existing IGI systems provide no direct synergistic linkage between the MDCT/video data and EBUS data. Hence, EBUS proves difficult to use and can lead to inaccurate interpretations. To address this drawback, we present a prototype of a multimodal IGI system that brings together the various image sources. The system enables 3D reconstruction and visualization of structures depicted in the 2D EBUS video stream. It also provides a set of graphical tools that link the EBUS data directly to the 3D MDCT and bronchoscopic video. Results using phantom and human data indicate that the new system could potentially enable smooth natural incorporation of EBUS into the system-level work flow of bronchoscopy.

Zang, Xiaonan; Bascom, Rebecca; Gilbert, Christopher R.; Toth, Jennifer W.; Higgins, William E.

2014-03-01

293

3-D-CT reconstructions in fractures of the skull base and facial skeleton  

International Nuclear Information System (INIS)

3-D reconstructions of the skull base, temporal bone, and skull fractures were compared to 2-D CT to evaluate the diagnostic value in traumatized patients. 38 patients with 22 fractures of the facial skeleton (orbita, zygomatic, Le Fort), 12 temporal bone, and 4 skull fractures were investigated. Subjective grading was perfomed by two physicians (ENT/RAD) in respect of quality diagnostic validity and estimated clinical impact. The average image validity and quality were graded good. In the temporal bone the average information supplied by 3-D was of inferior value; here, the lack of information regarding the inner ear structures was responsible for the lack of clinical impact. In fractures of the facial skeleton and the skull base of good to very good image quality was seen and clinical relevance was high. 3-D CT is capable of demonstrating fractures, which is of little value in the temporal bone, but of high value in the skull base and the facial skeleton, especially if surfaces are involved or fragments are displaced. (orig.)

1994-02-01

294

Application of approximation neural networks to the light line for 3D reconstruction of objects  

Science.gov (United States)

A technique for 3D object shape detection based on light line image processing is presented. In this process, an approximation neural network is used to reconstruct the 3D object shape. This neural network is generated using images of a light line projected onto the objects, whose dimensions are known. These images are obtained in the scanning step of the light line onto the objects. The profilometric method used by the neural network is based on the light line deformations. These deformations are measured by the Gaussian approximation method. In this technique, the 3D shape is obtained without use the parameters of the experimental set-up. It is an advantage over conventional methods of the light line projection. In this manner, the accuracy is improved due to the errors are not introduces in the system, The accuracy in this technique is deduced by the rms value. This technique is tested with simulations and real objects. Also, the time processing and accuracy results are presented.

Rodriguez, J. A. M.; Asundi, A.; Vera, R. R.

2004-10-01

295

Real-time 3-D Reconstruction by Means of Structured Light Illumination  

Science.gov (United States)

Structured light illumination (SLI) is the process of projecting a series of light striped patterns such that, when viewed at an angle, a digital camera can reconstruct a 3-D model of a target object's surface. But by relying on a series of time multiplexed patterns, SLI is not typically associated with video applications. For this purpose of acquiring 3-D video, a common SLI technique is to drive the projector/camera pair at very high frame rates such that any object's motion is small over the pattern set. But at these high frame rates, the speed at which the incoming video can be processed becomes an issue. So much so that many video-based SLI systems record camera frames to memory and then apply off-line processing. In order to overcome this processing bottleneck and produce 3-D point clouds in real-time, we present a lookup-table (LUT) based solution that in our experiments, using a 640 by 480 video stream, can generate intermediate phase data at 1063.8 frames per second and full 3-D coordinate point clouds at 228.3 frames per second. These achievements are 25 and 10 times faster than previously reported studies. At the same time, a novel dual-frequency pattern is developed which combines a high-frequency sinusoid component with a unit-frequency sinusoid component, where the high-frequency component is used to generate robust phase information and the unit-frequency component is used to reduce phase unwrapping ambiguities. Finally, we developed a gamma model for SLI, which can correct the non-linear distortion caused by the optical devices. For three-step phase measuring profilometry (PMP), analysis of the root mean squared error of the corrected phase showed a 60x reduction in phase error when the gamma calibration is performed versus 33x reduction without calibration. KEYWORDS: Real-time 3-D Reconstruction, Structured Light Illumination, Phase Measuring Profilometry, Gamma Correction, Phase Channel Multiplexing Pattern.

Liu, Kai

296

Development and Implementation of a Web-Enabled 3D Consultation Tool for Breast Augmentation Surgery Based on 3D-Image Reconstruction of 2D Pictures  

Science.gov (United States)

Background Producing a rich, personalized Web-based consultation tool for plastic surgeons and patients is challenging. Objective (1) To develop a computer tool that allows individual reconstruction and simulation of 3-dimensional (3D) soft tissue from ordinary digital photos of breasts, (2) to implement a Web-based, worldwide-accessible preoperative surgical planning platform for plastic surgeons, and (3) to validate this tool through a quality control analysis by comparing 3D laser scans of the patients with the 3D reconstructions with this tool from original 2-dimensional (2D) pictures of the same patients. Methods The proposed system uses well-established 2D digital photos for reconstruction into a 3D torso, which is then available to the user for interactive planning. The simulation is performed on dedicated servers, accessible via Internet. It allows the surgeon, together with the patient, to previsualize the impact of the proposed breast augmentation directly during the consultation before a surgery is decided upon. We retrospectively conduced a quality control assessment of available anonymized pre- and postoperative 2D digital photographs of patients undergoing breast augmentation procedures. The method presented above was used to reconstruct 3D pictures from 2D digital pictures. We used a laser scanner capable of generating a highly accurate surface model of the patient’s anatomy to acquire ground truth data. The quality of the computed 3D reconstructions was compared with the ground truth data used to perform both qualitative and quantitative evaluations. Results We evaluated the system on 11 clinical cases for surface reconstructions and 4 clinical cases of postoperative simulations, using laser surface scan technologies showing a mean reconstruction error between 2 and 4 mm and a maximum outlier error of 16 mm. Qualitative and quantitative analyses from plastic surgeons demonstrate the potential of these new emerging technologies. Conclusions We tested our tool for 3D, Web-based, patient-specific consultation in the clinical scenario of breast augmentation. This example shows that the current state of development allows for creation of responsive and effective Web-based, 3D medical tools, even with highly complex and time-consuming computation, by off-loading them to a dedicated high-performance data center. The efficient combination of advanced technologies, based on analysis and understanding of human anatomy and physiology, will allow the development of further Web-based reconstruction and predictive interfaces at different scales of the human body. The consultation tool presented herein exemplifies the potential of combining advancements in the core areas of computer science and biomedical engineering with the evolving areas of Web technologies. We are confident that future developments based on a multidisciplinary approach will further pave the way toward personalized Web-enabled medicine.

Garcia, Jaime; Olariu, Radu; Dindoyal, Irving; Le Huu, Serge

2012-01-01

297

Effect of Digital Fringe Projection Parameters on 3d Reconstruction Accuracy  

Science.gov (United States)

3D reconstruction has been already one of the most interesting research areas among photogrammetry and computer vision researchers. This thesis aims to evaluate digital fringe projection method in reconstruction of small objects with complicated shape. Digital fringe projection method is a novel method in structured light technique which integrates interferometric and triangulation methods. In this method, a digital projector projects a series of sinusoidal fringe patterns onto the object surface. Then, a camera from a different point of view captures images of patterns that are deformed due to object's surface topography. Afterward, the captured images will be processed and the depth related phase would be calculated. Due to using arctangent function in the process of phase extraction, the computed phase ranges from -pi to +pi, so a phase unwrapping step is necessary. Finally, the unwrapped phase map would be converted to depth map with some mathematical models. This method has many advantages like high speed, high accuracy, low cost hardware, high resolution (each pixel will have a depth at end), and simple computations. This paper aims to evaluate different parameters which affect the accuracy of the final results. For this purpose, some test were designed and implemented. These tests assess the number of phase shifts, spatial frequency of the fringe pattern, light condition, noise level of images, and the color and material of target objects on the quality of resulted phase map. The evaluation results demonstrate that digital fringe projection method is capable of obtaining depth map of complicated object with high accuracy. The contrast test results showed that this method is able to work under different ambient light condition; although at places with high light condition will not work properly. The results of implementation on different objects with various materials, color and shapes demonstrate the high capability of this method of 3D reconstruction.

Babaei, A.; Saadatseresht, M.

2013-09-01

298

Reconstruction of 3d video from 2d real-life sequences / Reconstrucción de video 3d desde secuencias reales en 2d  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish En este artículo, se propone un método novedoso que permite generar secuencias de video en 3D usando secuencias de video reales en 2D. La reconstrucción de la secuencia de video en 3D se realiza usando el cálculo del mapa de profundidad y la síntesis de anaglifos. El mapa de profundidad es formado u [...] sando la técnica de correspondencia estéreo basada en la minimización de la energía de error global a partir de funciones de suavizado. La construcción del anaglifo es realizada usando la alineación del componente de color interpolándolo con el mapa de profundidad previamente formado. Adicionalmente, se emplea la transformación del mapa de profundidad para reducir el rango dinámico de los valores de disparidad, minimizando el efecto fantasma mejorando la preservación de color. Se usaron numerosas secuencias de video a color reales que contienen diferentes tipos de movimientos como traslacional, rotacional, acercamiento, y la combinación de los anteriores, demostrando buen funcionamiento visual de la reconstrucción de secuencias de video en 3D propuesta. Abstract in english In this paper, a novel method that permits to generate 3D video sequences using 2D real-life sequences is proposed. Reconstruction of 3D video sequence is realized using depth map computation and anaglyph synthesis. The depth map is formed employing the stereo matching technique based on global erro [...] r energy minimization with smoothing functions. The anaglyph construction is implemented using the red component alignment interpolating the previously formed depth map. Additionally, the depth map transformation is realized in order to reduce the dynamic range of the disparity values, minimizing ghosting and enhancing color preservation. Several real-life color video sequences that contain different types of motions, such as translational, rotational, zoom and combination of previous ones are used demonstrating good visual performance of the proposed 3D video sequence reconstruction.

Ramos Diaz, Eduardo; Ponomaryov, Volodymyr.

299

3D reconstruction and spatial auralization of the "Painted Dolmen" of Antelas  

Science.gov (United States)

This paper presents preliminary results on the development of a 3D audiovisual model of the Anta Pintada (painted dolmen) of Antelas, a Neolithic chamber tomb located in Oliveira de Frades and listed as Portuguese national monument. The final aim of the project is to create a highly accurate Virtual Reality (VR) model of this unique archaeological site, capable of providing not only visual but also acoustic immersion based on its actual geometry and physical properties. The project started in May 2006 with in situ data acquisition. The 3D geometry of the chamber was captured using a Laser Range Finder. In order to combine the different scans into a complete 3D visual model, reconstruction software based on the Iterative Closest Point (ICP) algorithm was developed using the Visualization Toolkit (VTK). This software computes the boundaries of the room on a 3D uniform grid and populates its interior with "free-space nodes", through an iterative algorithm operating like a torchlight illuminating a dark room. The envelope of the resulting set of "free-space nodes" is used to generate a 3D iso-surface approximating the interior shape of the chamber. Each polygon of this surface is then assigned the acoustic absorption coefficient of the corresponding boundary material. A 3D audiovisual model operating in real-time was developed for a VR Environment comprising head-mounted display (HMD) I-glasses SVGAPro, an orientation sensor (tracker) InterTrax 2 with 3 Degrees Of Freedom (3DOF) and stereo headphones. The auralisation software is based on a geometric model. This constitutes a first approach, since geometric acoustics have well-known limitations in rooms with irregular surfaces. The immediate advantage lies in their inherent computational efficiency, which allows real-time operation. The program computes the early reflections forming the initial part of the chamber's impulse response (IR), which carry the most significant cues for source localisation. These early reflections are processed through Head Related Transfer Functions (HRTF) updated in real-time according to the orientation of the user's head, so that sound waves appear to come from the correct location in space, in agreement with the visual scene. The late-reverberation tail of the IR is generated by an algorithm designed to match the reverberation time of the chamber, calculated from the actual acoustic absorption coefficients of its surfaces. The sound output to the headphones is obtained by convolving the IR with anechoic recordings of the virtual audio source.

Dias, Paulo; Campos, Guilherme; Santos, Vítor; Casaleiro, Ricardo; Seco, Ricardo; Sousa Santos, Beatriz

2008-03-01

300

3D-ANTLERS: Virtual Reconstruction and Three-Dimensional Measurement  

Science.gov (United States)

The main objective of this paper is to establish a procedural method for measuring and cataloguing antlers through the use of laser scanner and of a 3D reconstruction of complex modeling. The deer's antlers have been used as a test and subjected to capture and measurement. For this purpose multiple data sources techniques have been studied and compared, (also considering low-cost sensors) estimating the accuracy and its errors in order to demonstrate the validity of the process. A further development is the comparison of results with applications of digital photogrammetry, considering also cloud computing software. The study has began with an introduction to sensors, addressing the underlying characteristics of the technology available, the scope and the limits of these applications. We have focused particularly on the "structured light", as the acquisition will be completed through three-dimensional scanners: DAVID and the ARTEC MH. The first is a low-cost sensor, a basic webcam and a linear laser pointer, red coloured, that leads to acquisition of three-dimensional strips. The other one is a hand scanner; even in this case we will explain how to represent a 3D model, with a pipeline that provides data export from the "proprietary" to a "reverse engineering" software. Typically, these are the common steps to the two approaches that have been performed in WRAP format: point sampling, manual and global registration, repair normals, surface editing and texture projection. In fact, after a first and common data processing was done with the use of a software supplied with the equipment, the proto-models thus obtained were treated in Geomagic Studio, which was also chosen to allow the homogenization and standardization of data in order to make a more objective comparison. It is commonplace to observe that the editing of the digital mock-up obtained with the DAVID - which had not yet been upgraded to the 3.5 release at the time of this study - is substantially different. In the ARTEC digital mock-up for example, it shows the ability to select the individual frames, already polygonal and geo-referenced at the time of capture; however, it is not possible to make an automated texturization differently from the low-cost environment which allows to produce a good graphics' definition. Once the final 3D models were obtained, we have proceeded to do a geometric and graphic comparison of the results. Therefore, in order to provide an accuracy requirement and an assessment for the 3D reconstruction we have taken into account the following benchmarks: cost, captured points, noise (local and global), shadows and holes, operability, degree of definition, quality and accuracy. Subsequently, these studies carried out in an empirical way on the virtual reconstructions, a 3D documentation was codified with a procedural method endorsing the use of terrestrial sensors for the documentation of antlers. The results thus pursued were compared with the standards set by the current provisions (see "Manual de medición" of Government of Andalusia-Spain); to date, in fact, the identification is based on data such as length, volume, colour, texture, openness, tips, structure, etc. Data, which is currently only appreciated with traditional instruments, such as tape measure, would be well represented by a process of virtual reconstruction and cataloguing.

Barba, S.; Fiorillo, F.; De Feo, E.

2013-02-01

 
 
 
 
301

CUDA based Level Set Method for 3D Reconstruction of Fishes from Large Acoustic Data  

DEFF Research Database (Denmark)

Acoustic images present views of underwater dynamics, even in high depths. With multi-beam echo sounders (SONARs), it is possible to capture series of 2D high resolution acoustic images. 3D reconstruction of the water column and subsequent estimation of fish abundance and fish species identification is highly desirable for planning sustainable fisheries. Main hurdles in analysing acoustic images are the presence of speckle noise and the vast amount of acoustic data. This paper presents a level set formulation for simultaneous fish reconstruction and noise suppression from raw acoustic images. Despite the presence of speckle noise blobs, actual fish intensity values can be distinguished by extremely high values, varying exponentially from the background. Edge detection generally gives excessive false edges that are not reliable. Our approach to reconstruction is based on level set evolution using Mumford-Shah segmentation functional that does not depend on edges in an image. We use the implicit function in conjunction with the image to robustly estimate a threshold for suppressing noise in the image by solving a second differential equation. We provide details of our estimation of suppressing threshold and show its convergence as the evolution proceeds. We also present a GPU based streaming computation of the method using NVIDIA's CUDA framework to handle large volume data-sets. Our implementation is optimised for memory usage to handle large volumes.

Sharma, Ojaswa; Anton, François

2009-01-01

302

Scatter compensation methods in 3D iterative SPECT reconstruction: A simulation study  

International Nuclear Information System (INIS)

Effects of different scatter compensation methods incorporated in fully 3D iterative reconstruction are investigated. The methods are: (i) the inclusion of an 'ideal scatter estimate' (ISE); (ii) like (i) but with a noiseless scatter estimate (ISE-NF); (iii) incorporation of scatter in the point spread function during iterative reconstruction ('ideal scatter model', ISM); (iv) no scatter compensation (NSC); (v) ideal scatter rejection (ISR), as can be approximated by using a camera with a perfect energy resolution. The iterative method used was an ordered subset expectation maximization (OS-EM) algorithm. A cylinder containing small cold spheres was used to calculate contrast-to-noise curves. For a brain study, global errors between reconstruction and 'true' distributions were calculated. Results show that ISR is superior to all other methods. In all cases considered, ISM is superior to ISE and performs approximately as well as (brain study) or better than (cylinder data) ISE-NF. Both ISM and ISE improve contrast-to-noise curves and reduce global errors, compared with NSC. In the case of ISE, blurring of the scatter estimate with a Gaussian kernel results in slightly reduced errors in brain studies, especially at low count levels. The optimal Gaussian kernel size is strongly dependent on the noise level. (author)

1997-08-01

303

Accurate 3D reconstruction by a new PDS-OSEM algorithm for HRRT  

Science.gov (United States)

State-of-the-art high resolution research tomography (HRRT) provides high resolution PET images with full 3D human brain scanning. But, a short time frame in dynamic study causes many problems related to the low counts in the acquired data. The PDS-OSEM algorithm was proposed to reconstruct the HRRT image with a high signal-to-noise ratio that provides accurate information for dynamic data. The new algorithm was evaluated by simulated image, empirical phantoms, and real human brain data. Meanwhile, the time activity curve was adopted to validate a reconstructed performance of dynamic data between PDS-OSEM and OP-OSEM algorithms. According to simulated and empirical studies, the PDS-OSEM algorithm reconstructs images with higher quality, higher accuracy, less noise, and less average sum of square error than those of OP-OSEM. The presented algorithm is useful to provide quality images under the condition of low count rates in dynamic studies with a short scan time.

Chen, Tai-Been; Horng-Shing Lu, Henry; Kim, Hang-Keun; Son, Young-Don; Cho, Zang-Hee

2014-03-01

304

Adaptive Geometric Tessellation for 3D Reconstruction of Anisotropically Developing Cells in Multilayer Tissues from Sparse Volumetric Microscopy Images  

Science.gov (United States)

The need for quantification of cell growth patterns in a multilayer, multi-cellular tissue necessitates the development of a 3D reconstruction technique that can estimate 3D shapes and sizes of individual cells from Confocal Microscopy (CLSM) image slices. However, the current methods of 3D reconstruction using CLSM imaging require large number of image slices per cell. But, in case of Live Cell Imaging of an actively developing tissue, large depth resolution is not feasible in order to avoid damage to cells from prolonged exposure to laser radiation. In the present work, we have proposed an anisotropic Voronoi tessellation based 3D reconstruction framework for a tightly packed multilayer tissue with extreme z-sparsity (2–4 slices/cell) and wide range of cell shapes and sizes. The proposed method, named as the ‘Adaptive Quadratic Voronoi Tessellation’ (AQVT), is capable of handling both the sparsity problem and the non-uniformity in cell shapes by estimating the tessellation parameters for each cell from the sparse data-points on its boundaries. We have tested the proposed 3D reconstruction method on time-lapse CLSM image stacks of the Arabidopsis Shoot Apical Meristem (SAM) and have shown that the AQVT based reconstruction method can correctly estimate the 3D shapes of a large number of SAM cells.

Chakraborty, Anirban; Perales, Mariano M.; Reddy, G. Venugopala; Roy-Chowdhury, Amit K.

2013-01-01

305

An evaluation of three-dimensional surface-reconstruction CT (3D-CT) in children with craniosynostosis  

International Nuclear Information System (INIS)

In this study, 3D-CT images were reconstructed from axial computed tomographic scans using the new software on 10 children with craniosynostosis. The authors discuss the advantages of the 3D-CT imaging technique in the diagnosis and surgical planning for craniosynostosis. The following conclusions may be drawn: 1) The images obtained from the new 3D-CT software are more accurate and realistic than the images previously reported by Vannier and Marsh. Reconstruction artifacts, known as pseudoforamina, have not appeared in the 3D-CT images reconstructed by the new software, and the top axial view of the 3D-CT reveals precisely anatomical details of the intracranial skull base. 2) The use of this new method provides accurate anatomical data which cannot be obtained by means of conventional radiological techniques in living subjects. 3) This technique of three-dimensional reconstruction from CT scans is most helpful in surgical planning and in the postoperative assessments of surgical results for craniosynostosis. The 3D-CT images allow the surgeon to visualize precisely the abnormalities of the skull to be corrected by the craniofacial surgery. Based on our experience with this study, we would expect that three-dimensional surface reconstruction from CT scans will henceforth be widely used in the planning of craniofacial surgery and in the postoperative follow-up assessment of craniosynostosis or craniofacial anomalies. (J.P.N.)

1987-01-01

306

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

Science.gov (United States)

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 scene. PMID:24776435

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

2013-12-01

307

Operator-free, film-based 3D seed reconstruction in brachytherapy  

International Nuclear Information System (INIS)

In brachytherapy implants, the accuracy of dose calculation depends on the ability to localize radioactive sources correctly. If performed manually using planar images, this is a time-consuming and often error-prone process - primarily because each seed must be identified on (at least) two films. In principle, three films should allow automatic seed identification and position reconstruction; however, practical implementation of the numerous algorithms proposed so far appears to have only limited reliability. The motivation behind this work is to create a fast and reliable system for real-time implant evaluation using digital planar images obtained from radiotherapy simulators, or mobile x-ray/fluoroscopy systems. We have developed algorithms and code for 3D seed coordinate reconstruction. The input consists of projections of seed positions in each of three isocentric images taken at arbitrary angles. The method proposed here consists of a set of heuristic rules (in a sense, a learning algorithm) that attempts to minimize seed misclassifications. In the clinic, this means that the system must be impervious to errors resulting from patient motion as well as from finite tolerances accepted in equipment settings. The software program was tested with simulated data, a pelvic phantom and patient data. One hundred and twenty permanent prostate implants were examined (105125I and 15103Pd) with the number of seeds ranging from 35 to 138 (average 79). The mean distance between actual and reconstructed seed positions is in the range 0.03-0.11 cm. On a Pentium III computer at 600 MHz the reconstruction process takes 10-30 s. The total number of seeds is independently validated. The process is robust and able to account for errors introduced in the clinic. (author)

2002-06-21

308

3D Scanning Cloud Radar Observations at Azores during the ARM AMF field campaign: Reconstruction and study of 3D cloud structures and properties  

Science.gov (United States)

The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) has been operating at Graciosa Island (Azores) since May 2009. This 21-month field campaign focuses on the study of marine stratus clouds. The ARM/AMF instrumentation and location provides a unique opportunity to observe the cloud properties of marine stratocumulus utilizing a variety of active and passive remote sensors. In addition to the standard profiling instrumentation, the first scanning W-band (94-GHz) ARM Cloud Radar (SWACR) was deployed for a short two-month period (October-November 2009). Several scan strategies were tested during the SWACR deployment. The scan strategies were designed specifically to provide the ability to reconstruct the 3D cloud structure. The raw radar observations are quality controlled with the identification of radar volumes with significant detections, water vapor attenuation and unfolding of the radar Doppler velocity. The observations are also transformed from the original radar coordinate system (spherical) to a Cartesian coordinate system using an adaptive gridding algorithm. The 3D gridding of the radar observables, along with spatial data analysis, allow us to evaluate important issues, specifically spatial variability of cloud and drizzle structures. Column profiles of SWACR observables are used in combination with Liquid Water Path measurements from the collocated Microwave Radiometer (MWR) to develop new relationships to compute Liquid Water Content (LWC). The best possible estimate of the 3D LWC structure is reconstructed by assessing both our relationship and other known relationships between radar reflectivity and LWC. This is required in order to use the 3D cloud observations for radiative transfer modeling. Additional drizzle-identification techniques are also being developed to allow the isolation of 3D cloud-only or liquid-only fields. These types of variables have a key impact on the understanding of the radiative budget of marine stratocumulus. Furthermore, this type of analysis can provide key information for the modeling of such clouds.

Bowley, K.; Jo, I.; Tatarevic, A.; Kollias, P.

2010-12-01

309

A new multiresolution method applied to the 3D reconstruction of small bodies  

Science.gov (United States)

The knowledge of the three-dimensional (3D) shape of small solar system bodies, such as asteroids and comets, is essential in determining their global physical properties (volume, density, rotational parameters). It also allows performing geomorphological studies of their surface through the characterization of topographic features, such as craters, faults, landslides, grooves, hills, etc.. In the case of small bodies, the shape is often only constrained by images obtained by interplanetary spacecrafts. Several techniques are available to retrieve 3D global shapes from these images. Stereography which relies on control points has been extensively used in the past, most recently to reconstruct the nucleus of comet 9P/Tempel 1 [Thomas (2007)]. The most accurate methods are however photogrammetry and photoclinometry, often used in conjunction with stereography. Stereophotogrammetry (SPG) has been used to reconstruct the shapes of the nucleus of comet 19P/Borrelly [Oberst (2004)] and of the asteroid (21) Lutetia [Preusker (2012)]. Stereophotoclinometry (SPC) has allowed retrieving an accurate shape of the asteroids (25143) Itokawa [Gaskell (2008)] and (2867) Steins [Jorda (2012)]. We present a new photoclinometry method based on the deformation of a 3D triangular mesh [Capanna (2012)] using a multi-resolution scheme which starts from a sphere of 300 facets and yields a shape model with 100; 000 facets. Our strategy is inspired by the "Full Multigrid" method [Botsch (2007)] and consists in going alternatively between two resolutions in order to obtain an optimized shape model at a given resolution before going to the higher resolution. In order to improve the robustness of our method, we use a set of control points obtained by stereography. Our method has been tested on images acquired by the OSIRIS visible camera, aboard the Rosetta spacecraft of the European Space Agency, during the fly-by of asteroid (21) Lutetia in July 2010. We present the corresponding 3D shape model of its surface and compare it with models obtained with the SPG and SPC methods. We finally illustrate the practical interest of our approach in geomorphological studies through an analysis of depth to diameter ratio of several craters and topographic properties of other features. Botsch, M., et al., "Geometric modeling based on polygonal meshes," Proc. ACM SIGGRAPH Course Notes, 2007 Capanna, C., et al.: 3D Reconstruction of small solar system bodies using photoclinometry by deformation, IADIS International Journal on Computer Science and Information Systems, in press, 2012. Gaskell, R. W., et al.: Characterizing and navigating small bodies with imaging data, Meteoritics and Planetary Science, vol 43, p. 1049, 2008. Jorda, L., et al: Asteroid (2867) Steins: Shape, Topography and Global Physical Properties from OSIRIS observations, Icarus, in press, 2012. Oberst, J., et al.: The nucleus of Comet Borrelly: a study of morphology and surface brightness, Icarus, vol. 167, 2004. Preusker, F., et al.: The northern hemisphere of asteroid 21 Lutetia topography and orthoimages from Rosetta OSIRIS NAC image data, Planetary and Space Science, vol. 66, p. 54-63, 2012. Thomas, P. C., et al.: The shape, topography, and geology of Tempel 1 from Deep Impact observations, Icarus, vol. 187, Issue 1, p. 4-15, 2007

Capanna, C.; Jorda, L.; Lamy, P. L.; Gesquiere, G.

2012-12-01

310

3D shape reconstruction of medical images using a perspective shape-from-shading method  

International Nuclear Information System (INIS)

A 3D shape reconstruction approach for medical images using a shape-from-shading (SFS) method was proposed in this paper. A new reflectance map equation of medical images was analyzed with the assumption that the Lambertian reflectance surface was irradiated by a point light source located at the light center and the image was formed under perspective projection. The corresponding static Hamilton–Jacobi (H–J) equation of the reflectance map equation was established. So the shape-from-shading problem turned into solving the viscosity solution of the static H–J equation. Then with the conception of a viscosity vanishing approximation, the Lax–Friedrichs fast sweeping numerical method was used to compute the viscosity solution of the H–J equation and a new iterative SFS algorithm was gained. Finally, experiments on both synthetic images and real medical images were performed to illustrate the efficiency of the proposed SFS method

2008-06-01

311

Building footprint database improvement for 3D reconstruction: A split and merge approach and its evaluation  

Science.gov (United States)

We present a general framework to improve a vectorial building footprint database consisting of a set of 2D polygons. The aim of this improvement is to make the database more proper to subsequent 3D building reconstruction at a large scale. Each polygon is split into several simple polygons guided by a digital elevation model (DEM). We say that this segmentation is vectorial as we produce segmentations that intrinsically have simple polygonal shapes, instead of doing a raster segmentation of the DEM within the polygon then trying to simplify it in a vectorization step. The method is based on a Mumford and Shah like energy functional characterizing the quality of the segmentation. We simplify the problem by imposing that the segmentation edges have directions present in the input polygon over which the DEM is defined. We evaluate the validity of the proposed method on a very large dataset and discuss its pros and cons based on this evaluation.

Vallet, Bruno; Pierrot-Deseilligny, Marc; Boldo, Didier; Brédif, Mathieu

2011-09-01

312

3D equilibrum reconstruction for the RFP with V3FIT  

Science.gov (United States)

Helical states are routinely found in all Reversed Field Pinch experiments and their description requires a 3D equilibrium reconstruction. We present the application of the V3FIT code for the RFX-mod experiment. Magnetic and kinetic diagnostics (Te from Thomson scattering, SXR emissivity, Ne from interferometer) are used in order to properly deal with the problem of degeneracy when only external magnetic measurements are used. A sensitivity study of external measurements on the internal topological structure is also presented, showing a link between external measurements and internal profiles. Fixed-boundary equilibria can be computed by independently calculating vacuum fields. The results provide a good match with experimental data and the obtained equilibria are suitable for both transport and stability analysis.

Terranova, David; Marrelli, Lionello; Hanson, James; Hirshman, Steven; Marco, Gobbin; Trevisan, Gregorio

2012-10-01

313

An analytic model of pinhole aperture penetration for 3D pinhole SPECT image reconstruction.  

Science.gov (United States)

Photons penetrate the attenuating material close to the aperture of pinhole collimators in nuclear medicine, broadening the tails of point spread functions (PSFs) and degrading the resolution of planar and SPECT images. An analytic approximation has been developed that models this penetration contribution to the PSF for knife-edge point pinhole apertures. The approximation has the form exp(-gamma r), where r is the distance on the detector surface from the projection of the point source through the pinhole. The rolloff coefficient gamma is a function of the photon energy, point source location and the design parameters of the collimator. There was excellent agreement between measured values of gamma from photon transport simulations of I-131 point sources (364 keV emission only) and theoretical predictions from the analytic formula. Predicted gamma values from the analytic formula averaged 25% greater than measured values from experimental I-131 point source acquisitions. Photon transport simulations were performed that modelled the 364 keV and less abundant 637 and 723 keV emissions and scatter within the scintillation crystal. Measured gamma values from these simulations averaged 12% greater than the experimental values, indicating that about half of the error between the analytic formula and the experimental measurements was due to unmodelled 637 and 723 keV emissions. The remaining error may be due in part to scatter in the pinhole region and backscatter from gamma camera components behind the scintillation crystal. The analytic penetration model was used in designing Metz filters to compensate for penetration blur and these filters were applied to the projection data as part of 3D SPECT image reconstruction. Image resolution and contrast were improved in simulated and experimental I-131 tumour phantom studies. This analytic model of pinhole aperture penetration can be readily incorporated into iterative 3D SPECT pinhole reconstruction algorithms. PMID:9572502

Smith, M F; Jaszczak, R J

1998-04-01

314

Zooming in: high resolution 3D reconstruction of differently stained histological whole slide images  

Science.gov (United States)

Much insight into metabolic interactions, tissue growth, and tissue organization can be gained by analyzing differently stained histological serial sections. One opportunity unavailable to classic histology is three-dimensional (3D) examination and computer aided analysis of tissue samples. In this case, registration is needed to reestablish spatial correspondence between adjacent slides that is lost during the sectioning process. Furthermore, the sectioning introduces various distortions like cuts, folding, tearing, and local deformations to the tissue, which need to be corrected in order to exploit the additional information arising from the analysis of neighboring slide images. In this paper we present a novel image registration based method for reconstructing a 3D tissue block implementing a zooming strategy around a user-defined point of interest. We efficiently align consecutive slides at increasingly fine resolution up to cell level. We use a two-step approach, where after a macroscopic, coarse alignment of the slides as preprocessing, a nonlinear, elastic registration is performed to correct local, non-uniform deformations. Being driven by the optimization of the normalized gradient field (NGF) distance measure, our method is suitable for differently stained and thus multi-modal slides. We applied our method to ultra thin serial sections (2 ?m) of a human lung tumor. In total 170 slides, stained alternately with four different stains, have been registered. Thorough visual inspection of virtual cuts through the reconstructed block perpendicular to the cutting plane shows accurate alignment of vessels and other tissue structures. This observation is confirmed by a quantitative analysis. Using nonlinear image registration, our method is able to correct locally varying deformations in tissue structures and exceeds the limitations of globally linear transformations.

Lotz, Johannes; Berger, Judith; Müller, Benedikt; Breuhahn, Kai; Grabe, Niels; Heldmann, Stefan; Homeyer, André; Lahrmann, Bernd; Laue, Hendrik; Olesch, Janine; Schwier, Michael; Sedlaczek, Oliver; Warth, Arne

2014-03-01

315

Reduced memory augmented Lagrangian algorithm for 3D iterative x-ray CT image reconstruction  

Science.gov (United States)

Although statistical image reconstruction methods for X-ray CT can provide improved image quality at reduced patient doses, computation times for 3D axial and helical CT are a challenge. Rapidly converging algorithms are needed for practical use. Augmented Lagrangian methods based on variable splitting recently have been found to be effective for image denoising and deblurring applications.5 These methods are particularly effective for non-smooth regularizers such as total variation or those involving the 1 norm. However, when standard "split Bregman" methods6 are applied directly to 3D X-ray CT problems, numerous auxiliary variables are needed, leading to undesirably high memory requirements.7 For minimizing regularized, weighted least-squares (WLS) cost functions, we propose a new splitting approach for CT, based on the alternating direction method of multipliers (ADMM)1,5 that has multiple benefits over previous methods: (i) reduced memory requirements, (ii) effective preconditioning using modified ramp/cone filters, (iii) accommodating very general regularizers including edge-preserving roughness penalties, total variation methods, and sparsifying transforms like wavelets. Numerical results show that the proposed algorithm converges rapidly, and that the cone filter is particularly effective for accelerating convergence.

McGaffin, Madison G.; Ramani, Sathish; Fessler, Jeffrey A.

2012-02-01

316

3D Reconstruction of the Vortex in a Human Right Ventricle Model using High Speed PIV  

Science.gov (United States)

This work aims to characterize the formation process and translation of the vortex, which forms along with the trans-tricuspid jet in a realistic model of a human right ventricle (RV). A clear model of the RV made of silicone rubber was carefully casted in real size from echocardiographic data of an adult human heart. The RV model was used in our heart pulsed-flow simulator at KLAB at UCI to perform experiments. Bioprosthetic heart valves in appropriate sizes were used at tricuspid and pulmonary positions. Multi-planar high-speed PIV was performed to capture and reconstruct the 3D flow field with a 1-millisecond time gap between each two velocity frames. ?2 iso-surfaces were used to illustrate the evolution of vortex cores. The highly asymmetric shape of the RV chamber results in a complex 3D trans-tricuspid vortex that forms and translates toward right ventricular outflow tract, and finally departs RV from pulmonary valve. Through this study, -for the first time- the formation, evolution and pathway of the RV vortex have been characterized in vitro.

Kheradvar, Arash; Falahatpisheh, Ahmad

2011-11-01

317

Improvement image in tomosynthesis  

International Nuclear Information System (INIS)

We evaluated the X-ray digital tomosynthesis (DT) reconstruction processing method for metal artifact reduction and the application of wavelet denoising to selectively remove quantum noise and suggest the possibility of image quality improvement using a novel application for chest. In orthopedic DT imaging, we developed artifact reduction methods based on a modified Shepp and Logan reconstruction filter kernel realized by taking into account additional weighing by direct current (DC) components in frequency domain space. Processing leads to an increase in the ratio of low-frequency components in an image. The effectiveness of the method in enhancing the visibility of a prosthetic case was quantified in terms of removal of ghosting artifacts. In chest DT imaging, the technique was implemented on a DT system and experimentally evaluated through chest phantom measurements, spatial resolution and compared with an existing post-reconstruction wavelet denoise algorithm by Badea et al. Our wavelet technique with balance sparsity-norm contrast-to-noise ratio (CNR) effectively decreased quantum noise in the reconstructed images with and improvement when applied to pre-reconstruction image for post-reconstruction. The results of our technique showed that although modulation transfer function (MTF) did not vary (preserving spatial resolution), the existing wavelet denoise algorithm caused MTF deterioration. (author)

2012-11-01

318

Optimal relaxation parameters of DRAMA (dynamic RAMLA) aiming at one-pass image reconstruction for 3D-PET  

International Nuclear Information System (INIS)

We have reported a block-iterative algorithm named DRAMA for image reconstruction for emission tomography (Tanaka and Kudo 2003 Phys. Med. Biol. 48 1405-22). DRAMA is a modified version of the row-action maximum likelihood algorithm (RAMLA), in which the relaxation parameter is subset dependent and is changed in such a way that the noise propagation from subsets to the reconstructed image is substantially independent of the access order of the subsets. The algorithm provides fast convergence with a reasonable signal-to-noise ratio. The optimal relaxation parameter has been derived assuming a two-dimensional (2D)-PET model, and detailed performance in three-dimensional (3D) reconstruction has not been clear enough. We have developed the new version 'DRAMA-3D', based on the 3D-PET model. The optimal relaxation parameter is a function of the access order of the subsets and the ring difference, and its value is determined by simple formulas from the design parameters of the PET scanner, the operating conditions and the post-smoothing resolution. In this paper, we present the theory of DRAMA-3D, the results of simulation studies on the performance of DRAMA-3D and the comparative studies of the related algorithms. It is shown that DRAMA-3D is robust for various access orders of subsets and is suitable to realize one-pass (single-iteration) reconstruction.

2010-05-21

319

3-D-CT reconstructions in fractures of the skull base and facial skeleton; 3-D-CT-Rekonstruktion bei Frakturen der Schaedelbasis und des Gesichtsschaedels  

Energy Technology Data Exchange (ETDEWEB)

3-D reconstructions of the skull base, temporal bone, and skull fractures were compared to 2-D CT to evaluate the diagnostic value in traumatized patients. 38 patients with 22 fractures of the facial skeleton (orbita, zygomatic, Le Fort), 12 temporal bone, and 4 skull fractures were investigated. Subjective grading was perfomed by two physicians (ENT/RAD) in respect of quality diagnostic validity and estimated clinical impact. The average image validity and quality were graded good. In the temporal bone the average information supplied by 3-D was of inferior value; here, the lack of information regarding the inner ear structures was responsible for the lack of clinical impact. In fractures of the facial skeleton and the skull base of good to very good image quality was seen and clinical relevance was high. 3-D CT is capable of demonstrating fractures, which is of little value in the temporal bone, but of high value in the skull base and the facial skeleton, especially if surfaces are involved or fragments are displaced. (orig.) [Deutsch] Aus computertomographischen Schichten wurden bei Frakturen des Schaedels 3-D-Rekonstruktionen angefertigt, um die diagnostische Aussage zu vergleichen. 38 Patienten wurden untersucht, es wurden 22 Gesichtsschaedel-, 4 Kalotten- und 12 Felsenbeinfrakturen bezueglich (1) Bildqualitaet, (2) diagnostischer Aussagekraft, (3) geschaetzter klinischer Wertigkeit bewertet. Die durchschnittlich erreichbare Bildqualitaet (Artefakte, Detailtreue) und diagnostische Aussagekraft wurden in der Gesamtauswertung als gut bewertet. Bei den Pyramidenfrakturen zeigte sich eine geringe diagnostische Wertigkeit, da die Beteiligung der Innenrohr- und Mittelohrstrukturen nicht abgrenzbar war. Die Gesichtsschaedel-, Jochbein- und Schaedelbasisfrakturen zeigten eine gute bis sehr gute Bildqualitaet und eine Wertung der 3-D-Rekonstruktionen als klinisch relevant. Bei den Felsenbeinfrakturen war die klinische Relevanz sehr eingeschraenkt, die 3-D-Rekonstruktionen koennen bei Gesichtsschaedelfrakturen jedoch eine uebersichtliche Darstellung von hoher Qualitaet und Wertigkeit erzielen, insbesondere wenn Oberflaechen bteiligt sind oder eine Verschiebung der Fragmente stattgefunden hat. (orig.)

Bruening, R. [Radiologische Universitaetsklinik, Bonn (Germany); Quade, R. [HNO-Universitaetsklinik, Bonn (Germany); Keppler, V. [Radiologische Universitaetsklinik, Bonn (Germany); Reiser, M. [Radiologische Universitaetsklinik, Bonn (Germany)

1994-02-01

320

A 3D Freehand Ultrasound System for Multi-view Reconstructions from Sparse 2D Scanning Planes  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background A significant limitation of existing 3D ultrasound systems comes from the fact that the majority of them work with fixed acquisition geometries. As a result, the users have very limited control over the geometry of the 2D scanning planes. Methods We present a low-cost and flexible ultrasound imaging system that integrates several image processing components to allow for 3D reconstructions from limited numbers of 2D image planes and multiple acoustic views. Our approach is based on a 3D freehand ultrasound system that allows users to control the 2D acquisition imaging using conventional 2D probes. For reliable performance, we develop new methods for image segmentation and robust multi-view registration. We first present a new hybrid geometric level-set approach that provides reliable segmentation performance with relatively simple initializations and minimum edge leakage. Optimization of the segmentation model parameters and its effect on performance is carefully discussed. Second, using the segmented images, a new coarse to fine automatic multi-view registration method is introduced. The approach uses a 3D Hotelling transform to initialize an optimization search. Then, the fine scale feature-based registration is performed using a robust, non-linear least squares algorithm. The robustness of the multi-view registration system allows for accurate 3D reconstructions from sparse 2D image planes. Results Volume measurements from multi-view 3D reconstructions are found to be consistently and significantly more accurate than measurements from single view reconstructions. The volume error of multi-view reconstruction is measured to be less than 5% of the true volume. We show that volume reconstruction accuracy is a function of the total number of 2D image planes and the number of views for calibrated phantom. In clinical in-vivo cardiac experiments, we show that volume estimates of the left ventricle from multi-view reconstructions are found to be in better agreement with clinical measures than measures from single view reconstructions. Conclusions Multi-view 3D reconstruction from sparse 2D freehand B-mode images leads to more accurate volume quantification compared to single view systems. The flexibility and low-cost of the proposed system allow for fine control of the image acquisition planes for optimal 3D reconstructions from multiple views.

Agurto Carla

2011-01-01

 
 
 
 
321

A LabVIEW based user-friendly nano-CT image alignment and 3D reconstruction platform  

CERN Document Server

X-ray nanometer computed tomography (nano-CT) offers applications and opportunities in many scientific researches and industrial areas. Here we present a user-friendly and fast LabVIEW based package running, after acquisition of the raw projection images, a procedure to obtain the inner structure of the sample under analysis. At first, a reliable image alignment procedure fixes possible misalignments among image series due to mechanical errors, thermal expansion and other external contributions, then a novel fast parallel beam 3D reconstruction performs the tomographic reconstruction. The remarkable improved reconstruction after the image calibration confirms the fundamental role of the image alignment procedure. It minimizes blurring and additional streaking artifacts present in a reconstructed slice that cause loss of information and faked structures in the observed material. The nano-CT image alignment and 3D reconstruction LabVIEW package significantly reducing the data process, makes faster and easier th...

Wang, Shenghao; Wang, Zhili; Gao, Kun; Wu, Zhao; Zhu, Peiping; Wu, Ziyu

2014-01-01

322

3D reconstruction of prostate histology based on quantified tissue cutting and deformation parameters  

Science.gov (United States)

Methods for 3D histology reconstruction from sparse 2D digital histology images depend on knowledge about the positions, orientations, and deformations of tissue slices due to the histology process. This work quantitatively evaluates typical assumptions about the position and orientation of whole-mount prostate histology sections within coarsely sliced tissue blocks and about the deformation of tissue during histological processing and sectioning. 3-5 midgland tissue blocks from each of 7 radical prostatectomy specimens were imaged using magnetic resonance imaging before histology processing. After standard whole-mount paraffin processing and sectioning, the resulting sections were digitised. Homologous anatomic landmarks were identified on 22 midgland histology and MR images. Orientations and depths of sections relative to the front faces of the tissue blocks were measured based on the best-fit plane through the landmarks on the MR images. The mean+/-std section orientation was 1.7+/-1.1° and the mean+/-std depth of the sections was 1.0+/-0.5 mm. Deformation was assessed by using four transformation models (rigid, rigid+scale, affine and thin-plate-spline (TPS)) to align landmarks from histology and MR images, and evaluating each by measuring the target registration error (TRE) using a leave-one-out cross-validation. The rigid transformation model had higher mean TRE (pprostate histology reconstruction based on extrinsic strand-shaped fiducial markers which yielded a 0.7+/-0.4 mm mean+/-std TRE.

Gibson, Eli; Gómez, José A.; Moussa, Madeleine; Crukley, Cathie; Bauman, Glenn; Fenster, Aaron; Ward, Aaron D.

2012-02-01

323

Cardiac C-arm computed tomography using a 3D + time ROI reconstruction method with spatial and temporal regularization  

International Nuclear Information System (INIS)

Purpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition. Methods: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization. Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction. Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection

2014-02-01

324

Cardiac C-arm computed tomography using a 3D + time ROI reconstruction method with spatial and temporal regularization  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition. Methods: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization. Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction. Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection.

Mory, Cyril, E-mail: cyril.mory@philips.com [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Auvray, Vincent; Zhang, Bo [Philips Research Medisys, 33 rue de Verdun, 92156 Suresnes (France); Grass, Michael; Schäfer, Dirk [Philips Research, Röntgenstrasse 24–26, D-22335 Hamburg (Germany); Chen, S. James; Carroll, John D. [Department of Medicine, Division of Cardiology, University of Colorado Denver, 12605 East 16th Avenue, Aurora, Colorado 80045 (United States); Rit, Simon [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France); Université Lyon 1 (France); Centre Léon Bérard, 28 rue Laënnec, F-69373 Lyon (France); Peyrin, Françoise [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, F-69621 Villeurbanne Cedex (France); X-ray Imaging Group, European Synchrotron, Radiation Facility, BP 220, F-38043 Grenoble Cedex (France); Douek, Philippe; Boussel, Loïc [Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon (France); Université Lyon 1 (France); Hospices Civils de Lyon, 28 Avenue du Doyen Jean Lépine, 69500 Bron (France)

2014-02-15

325

Spiral CT and 3D reconstruction of the tracheobronchial tree for individual double-lumen-tube-selection  

International Nuclear Information System (INIS)

Purpose: To assess the potential of 3 D spiral CT in the selection of adequate double-lumen tubes (DLT) for one-lung-ventilation. Materials and methods: 3 D-spiral CT of eight different DLTs was performed with standardized acquisition parameters: Section thickness 4 mm, table speed 6 mm/s, increment 3 mm and standardised thresholds, window settings and magnification zoom. The accuracy was confirmed by measuring 3 D objects on screen and original DLTs by vernier caliper. 3 D spiral CT was performed in 20 patients preoperatively with slice thickness 4-8 mm, pitch 1-1.5, increment 4-8 mm. To select the adequate DLT size the 3 D reconstructions of the patient's tracheobronchial tree and of the DLT were superimposed by templates or computer animation. The accuracy was controlled by endoscopic and clinical measurements. Results: The accuracy of the 3 D spiral CT was nearly 0.1 mm. The superimposition with templates was easy and reliable. The 3 D spiral CT determined DLTs were shown to fit perfectly by clinical and endoscopic measurements in all cases. Conclusion: 3 D reconstructions of the tracheobronchial tree obtained from routinepreoperative spiral CT scans allow for an easy and accurate individual selection of double-lumen tubes. (orig.)

1997-02-01

326

3D phase micro-object studies by means of digital holographic tomography supported by algebraic reconstruction technique  

Science.gov (United States)

Constant development of microelements' technology requires a creation of new instruments to determine their basic physical parameters in 3D. The most efficient non-destructive method providing 3D information is tomography. In this paper we present Digital Holographic Tomography (DHT), in which input data is provided by means of Di-git- al Holography (DH). The main advantage of DH is the capability to capture several projections with a single hologram [1]. However, these projections have uneven angular distribution and their number is significantly limited. Therefore - Algebraic Reconstruction Technique (ART), where a few phase projections may be sufficient for proper 3D phase reconstruction, is implemented. The error analysis of the method and its additional limitations due to shape and dimensions of investigated object are presented. Finally, the results of ART application to DHT method are also presented on data reconstructed from numerically generated hologram of a multimode fibre.

Bilski, B. J.; Jozwicka, A.; Kujawinska, M.

2007-09-01

327

Focussed ion beam serial sectioning and imaging of monolithic materials for 3D reconstruction and morphological parameter evaluation.  

Science.gov (United States)

A new characterisation method, based on the utilisation of focussed ion beam-scanning electron microscopy (FIB-SEM), has been employed for the evaluation of morphological parameters in porous monolithic materials. Sample FIB serial sectioning, SEM imaging and image processing techniques were used to extract the pore boundaries and reconstruct the 3D porous structure of carbon and silica-based monoliths. Since silica is a non-conducting material, a commercial silica monolith modified with activated carbon was employed instead to minimise the charge build-up during FIB sectioning. This work therefore presents a novel methodology that can be successfully employed for 3D reconstruction of porous monolithic materials which are or can be made conductive through surface or bulk modification. Furthermore, the 3D reconstructions were used for calculation of the monolith macroporosity, which was in good agreement with the porosity values obtained by mercury intrusion porosimetry (MIP). PMID:24157809

Vázquez, Mercedes; Moore, David; He, Xiaoyun; Ben Azouz, Aymen; Nesterenko, Ekaterina; Nesterenko, Pavel; Paull, Brett; Brabazon, Dermot

2014-01-01

328

Ricostruzione di una scena urbana 3D utilizzando VisualSfM. Reconstructing urban scene 3D using VisualSfM  

Directory of Open Access Journals (Sweden)

Full Text Available Le tecniche di computer vision oggi danno la possibilità di costruire in maniera rapida e automatica modelli 3D dettagliati a partire da dataset fotografici. La comunità accademica ha visto una crescente attenzione alla ricostruzione 3D a scala urbana. Tra i vari strumenti oggi a disposizione spicca VisualSfM sviluppato dall’università di Washingthon e Google. Si tratta di una Interfaccia grafica open source strutturata in algoritmi dedicati alla tecnica di Structure from Motion (SfM. VisualSfM utilizza un estrattore di features chiamato SIFTGPU e un algoritmo di Bundle Adjustment Multicore. Inoltre è possibile ottenere una nuvola di punti densa utilizzando gli algoritmi CMVS/PMVS2. La finalità di questo studio è di verificare l’accuratezza metrica delle ricostruzioni attraverso l’utilizzo integrato di VisualSfM e CMVS/PMVS2. L’approccio quindi è stato testato su diversi dataset di una certa entità strutturati da collezioni fotografiche ragionate.New computer vision techniques use photo dataset to rapidly build detailed 3D models. Computer- vision researchers have explored many approaches to city-scale 3D reconstruc on. Among these systems stands out VisualSfM developed by the University of Washington & Google Inc. It is a open source GUI applica on of a Structure from Mo on (SfM so! ware that uses a feature extractor called Si! GPU and the Mul core Bundle Adjustment. In addi on it embeds the CMVS/ PMVS2 able to reconstruct dense 3D point cloud. Our goal is to demonstrate the metric accuracy of VisualSfM+CMVS/PMVS2 and that to get run it, you can use an unstructured photo dataset but the result improves if you use a structured photo dataset. The approach has been tested on several large datasets with structured images.

Laura Inzerillo

2013-10-01

329

Computer-aided interactive surgical simulation for craniofacial anomalies based on 3-D surface reconstruction CT images  

International Nuclear Information System (INIS)

We developed a computer-aided interactive surgical simulation system for craniofacial anomalies based on three-dimensional (3-D) surface reconstruction CT imaging. This system has four functions: 1) 3-D surface reconstruction display with an accelerated projection method; 2) Surgical simulation to cut, move, rotate, and reverse bone-blocks over the reference 3-D image on the CRT screen; 3) 3-D display of the simulated image in arbitrary views; and 4) Prediction of postoperative skin surface features displayed as 3-D images in arbitrary views. Retrospective surgical simulation has been performed on three patients who underwent the fronto-orbital advancement procedures for brachycephaly and two who underwent the reconstructive procedure for scaphocephaly. The predicted configurations of the cranium and skin surface were well simulated when compared to the postoperative images in 3-D arbitrary views. In practical use, this software might be used for an on-line system connected to a large scale general-purpose computer. (author)

1988-01-01

330

Examination of a novel reconstruction function in 3D CT angiography  

International Nuclear Information System (INIS)

A novel reconstruction function, VR Kernel (VRK), was evaluated by comparison with the conventional standard function (Standard) for imaging of blood vessels and their morphology by 3D-CT angiography (3D-CTA) of abdomen. The machine was PHILIPS Brilliance CT64 with the workstation of Extended Brilliance Work Space and AZE Virtual Place Lexus, PHILIPS EBW AVA software was for measuring the blood vessel diameter, and image analytical software was that of Kanazawa Univ. for calculating modulation transfer function (MTF). Examinations were on the resolution and noise characteristics with use of PHILIPS head and trunk phantom, on shape appearance and diameters with Kyoto-Kagaku simulated blood vessel phantom and on visual observation of the actual clinical 3D-CTA image at the level of renal artery of human abdomen for seeing the surface shape and calcification on aorta and the capacity of image characterization of peripheral vessels. VRK was found to give higher MTF values at up to 0.4 cycles/mm than Standard, indicating satisfactory spatial resolution and as well, larger standard deviation (SD) values suggestive of lower image quality. However, in the examination of shape appearance, VRK image quality was comparable to Standard's and capacity was improved at 1.8-1.0 mm diameter, probably by the increased CT number of the vessels. Further, steeper peak was given in the profiling curve of the simulated vessel by VRK, suggesting its clearer imaging. At the normal level (image at CT number of aorta, ca. 350 HU and SD, ca. 10), the clinical image quality was seemingly improved in VRK, and the capacity to characterize peripheral vessels was better despite roughness of the whole image at the poor level (CT number, at 200 and SD, ca. 15). VRK was thus found to more clearly display the margin of blood vessels due to the improved image quality by increased CT number, and to give better shape appearance, and was thought to be more useful to observe the peripheral vessels. (T.T.)

2010-07-01

331

Vegetation Structure and 3-D Reconstruction of Forests Using Ground-Based Echidna® Lidar  

Science.gov (United States)

A ground-based, scanning, near-infrared lidar, the Echidna® validation instrument (EVI), built by CSIRO Australia, retrieves structural parameters of forest stands rapidly and accurately, and by merging multiple scans into a single point cloud provides 3-D stand reconstructions. Echidna lidar technology scans with pulses of light at 1064 nm wavelength and digitizes the light returns sufficiently finely to recover and distinguish the differing shapes of return pulses as they are scattered by leaves and trunks or larger branches. Instrument deployments in the New England region in 2007 and 2009 and in the southern Sierra Nevada of California in 2008 provided the opportunity to test the ability of the instrument to retrieve tree diameters, stem count density (stems/ha), basal area, and above-ground woody biomass from single scans at points beneath the forest canopy. In New England in 2007, mean parameters retrieved from five scans located within six 1-ha stand sites match manually-measured parameters with values of R2 = 0.94-0.99. Processing the scans to retrieve leaf area index (LAI) provided values within the range of those retrieved with other optical instruments and hemispherical photography. Foliage profiles, which measure leaf area with canopy height, showed distinctly different shapes for the stands, depending on species composition and age structure. Stand heights, obtained from foliage profiles, were not significantly different from RH100 values observed by the Laser Vegetation Imaging Sensor in 2003. Data from the California 2008 and New England 2009 deployments were still being processed at the time of abstract submission. With further hardware and software development, Echidna® technology will provide rapid and accurate measurements of forest canopy structure that can replace manual field measurements, leading to more rapid and more accurate calibration and validation of structure mapping techniques using airborne and spaceborne remote sensors. Three-dimensional stand reconstruction with the EVI uses full-waveform digitizing of return pulses to identify one or more “hits” along the pulse path coupled with the peak return of each hit expressed as apparent reflectance. Returns are also classified into trunk or leaf hits based on the shape of the return pulse, and an algorithm that searches for the return with the lowest height within a fine x-y grid identifies ground returns. These data are converted into a “point cloud” of hit locations, intensities, and object classes within a three-axis coordinate system centered at the instrument. Merging point clouds from overlapping scans produces the 3-D reconstructions. These reconstructions can in principle provide more realistic measurements of green and woody biomass as well as crown size and shape. They also point the way toward measurements of directional gap probability for applications in radiative transfer modeling. A second-generation instrument, the Dual-Wavelength Echidna Lidar (DWEL), is currently under development by the Echidna Lidar Team at Boston University with NSF support. This research is supported by NASA grants NNG06GI92G and NNX08AE94A and NSF grant DBI-0923389.

Strahler, A. H.; Yao, T.; Zhao, F.; Yang, X.

2009-12-01

332

Toward quantification of breast tomosynthesis imaging  

Science.gov (United States)

Due to the high prevalence of breast cancer among women, much is being done to detect breast cancer earlier and more accurately. In current clinical practice, the most widely-used mode of breast imaging is mammography. Its main advantages are high sensitivity and low patient dose, although it is still merely a two-dimensional projection of a three-dimensional object. In digital breast tomosynthesis, a three-dimensional image of the breast can be reconstructed, but x-ray projection images of the breast are taken over a limited angular span. However, the breast tomosynthesis device itself is more similar to a digital mammography system and thus is a feasible replacement for mammography. Because of the angular undersampling in breast tomosynthesis, the reconstructed images are not considered quantitative, so a worthwhile question to answer would be whether the voxel values (VVs) in breast tomosynthesis images can be made to indicate tissue type as Hounsfield units do in CT. through some image processing scheme. To investigate this, simple phantoms were imaged consisting of layers of uniform, tissue-equivalent plastic for the background sandwiching a layer of interest containing multiple, small cuboids of tissue-equivalent plastic. After analyzing the reconstructed tomosynthesis images, it was found that the VV in each lesion increases linearly with tissue glandularity. However, for the two different x-ray tube energies and for the two different beam exposure levels tested, the trend-lines all have different slopes and y-intercepts. Thus, breast tomosynthesis has a definite potential to be quantitative, and it would be worthwhile to study other possible dependent parameters (phantom thickness, overall density, etc.) as well as alternative reconstruction algorithms.

Shafer, Christina M.; Samei, Ehsan; Saunders, Robert S.; Zerhouni, Moustafa; Lo, Joseph Y.

2008-04-01

333

First report of fossil "keratose" demosponges in Phanerozoic carbonates: preservation and 3-D reconstruction  

Science.gov (United States)

Fossil record of Phanerozoic non-spicular sponges, beside of being important with respect to the lineage evolution per se, could provide valuable references for the investigation of Precambrian ancestral animal fossils. However, although modern phylogenomic studies resolve non-spicular demosponges as the sister group of the remaining spiculate demosponges, the fossil record of the former is extremely sparse or unexplored compared to that of the latter; the Middle Cambrian Vauxiidae Walcott 1920, is the only confirmed fossil taxon of non-spicular demosponges. Here, we describe carbonate materials from Devonian (Upper Givetian to Lower Frasnian) bioherms of northern France and Triassic (Anisian) microbialites of Poland that most likely represent fossil remnants of keratose demosponges. These putative fossils of keratose demosponges are preserved as automicritic clumps. They are morphologically distinguishable from microbial fabrics but similar to other spiculate sponge fossils, except that the skeletal elements consist of fibrous networks instead of assembled spicules. Consistent with the immunological behavior of sponges, these fibrous skeletons often form a rim at the edge of the automicritic aggregate, separating the inner part of the aggregate from foreign objects. To confirm the architecture of these fibrous networks, two fossil specimens and a modern thorectid sponge for comparison were processed for three-dimensional (3-D) reconstruction using serial grinding tomography. The resulting fossil reconstructions are three-dimensionally anastomosing, like modern keratose demosponges, but their irregular and nonhierarchical meshes indicate a likely verongid affinity, although a precise taxonomic conclusion cannot be made based on the skeletal architecture alone. This study is a preliminary effort, but an important start to identify fossil non-spicular demosponges in carbonates and to re-evaluate their fossilization potential.

Luo, Cui; Reitner, Joachim

2014-04-01

334

ESTIMATION OF TORTUOSITY AND RECONSTRUCTION OF GEODESIC PATHS IN 3D  

Directory of Open Access Journals (Sweden)

Full Text Available The morphological tortuosity of a geodesic path in a medium can be defined as the ratio between its geodesic length and the Euclidean distance between its two extremities. Thus, the minimum tortuosity of all the geodesic paths into a medium in 2D or in 3D can be estimated by image processing methodsusing mathematical morphology. Considering a medium, the morphological tortuosities of its internal paths are estimated according to one direction, which is perpendicular to both starting and ending opposite extremities of the geodesicpaths. The used algorithm estimates the morphological tortuosities from geodesic distance maps, which are obtained from geodesic propagations. The shape of the propagated structuring element used to estimate the geodesic distance maps on a discrete grid has a direct influence on the morphological tortuosity and has to be chosen very carefully. The results of our algorithm is an image with pixels p having a value equal to the length of the shortest path containing p and connected to two considered opposite boundaries A and B of the image. The analysis of the histogram of the morphological tortuosities gives access to their statistical distribution. Moreover, for each tortuosity the paths can be extracted from the original image, which highlights the location of them into the sample. However, these geodesic paths have to be reconstructed for further processing. The extraction, because applying a threshold on the tortuosities, results in disconnected components, especially for highly tortuous paths. This reconstruction consists in reconnecting these components to the geodesic path linking the two opposite faces, by means of a backtracking algorithm.

Charles Peyrega

2013-03-01

335

Body mass estimations for Plateosaurus engelhardti using laser scanning and 3D reconstruction methods  

Science.gov (United States)

Both body mass and surface area are factors determining the essence of any living organism. This should also hold true for an extinct organism such as a dinosaur. The present report discusses the use of a new 3D laser scanner method to establish body masses and surface areas of an Asian elephant (Zoological Museum of Copenhagen, Denmark) and of Plateosaurus engelhardti, a prosauropod from the Upper Triassic, exhibited at the Paleontological Museum in Tübingen (Germany). This method was used to study the effect that slight changes in body shape had on body mass for P. engelhardti. It was established that body volumes varied between 0.79 m3 (slim version) and 1.14 m3 (robust version), resulting in a presumable body mass of 630 and 912 kg, respectively. The total body surface areas ranged between 8.8 and 10.2 m2, of which, in both reconstructions of P. engelhardti, ˜33% account for the thorax area alone. The main difference between the two models is in the tail and hind limb reconstruction. The tail of the slim version has a surface area of 1.98 m2, whereas that of the robust version has a surface area of 2.73 m2. The body volumes calculated for the slim version were as follows: head 0.006 m3, neck 0.016 m3, fore limbs 0.020 m3, hind limbs 0.08 m3, thoracic cavity 0.533 m3, and tail 0.136 m3. For the robust model, the following volumes were established: 0.01 m3 head, neck 0.026 m3, fore limbs 0.025 m3, hind limbs 0.18 m3, thoracic cavity 0.616 m3, and finally, tail 0.28 m3. Based on these body volumes, scaling equations were used to assess the size that the organs of this extinct dinosaur have.

Gunga, Hanns-Christian; Suthau, Tim; Bellmann, Anke; Friedrich, Andreas; Schwanebeck, Thomas; Stoinski, Stefan; Trippel, Tobias; Kirsch, Karl; Hellwich, Olaf

2007-08-01

336

3-D reconstruction of anterior mantle-field techniques in Hodgkin's disease survivors: doses to cardiac structures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background The long-term dose-effect relationship for specific cardiac structures in mediastinal radiotherapy has rarely been investigated. As part of an interdisciplinary project, the 3-D dose distribution within the heart was reconstructed in all long-term Hodgkin's disease survivors (n = 55) treated with mediastinal radiotherapy between 1978 and 1985. For dose reconstruction, original techniques were transferred to the CT data sets of appropriate test patients, in...

2006-01-01

337

Automation of 3D reconstruction of neural tissue from large volume of conventional Serial Section Transmission Electron Micrographs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe an approach for automation of the process of reconstruction of neural tissue from serial section transmission electron micrographs. Such reconstructions require 3D segmentation of individual neuronal processes (axons and dendrites) performed in densely packed neuropil. We first detect neuronal cell profiles in each image in a stack of serial micrographs with multi-scale ridge detector. Short breaks in detected boundaries are interpolated using anisotropic contour completion formul...

Mishchenko, Yuriy

2009-01-01

338

Fast iterative image reconstruction methods for fully 3D multispectral bioluminescence tomography  

International Nuclear Information System (INIS)

We investigate fast iterative image reconstruction methods for fully 3D multispectral bioluminescence tomography for applications in small animal imaging. Our forward model uses a diffusion approximation for optically inhomogeneous tissue, which we solve using a finite element method (FEM). We examine two approaches to incorporating the forward model into the solution of the inverse problem. In a conventional direct calculation approach one computes the full forward model by repeated solution of the FEM problem, once for each potential source location. We describe an alternative on-the-fly approach where one does not explicitly solve for the full forward model. Instead, the solution to the forward problem is included implicitly in the formulation of the inverse problem, and the FEM problem is solved at each iteration for the current image estimate. We evaluate the convergence speeds of several representative iterative algorithms. We compare the computation cost of those two approaches, concluding that the on-the-fly approach can lead to substantial reductions in total cost when combined with a rapidly converging iterative algorithm

2008-07-21

339

AX-PET A novel PET detector concept with full 3D reconstruction  

CERN Document Server

We describe the concept and first experimental tests of a novel 3D axial Positron Emission Tomography (PET) geometry. It allows for a new way of measuring the interaction point in the detector with very high precision. It is based on a matrix of long Lutetium-Yttrium OxyorthoSilicate (LYSO) crystals oriented in the axial direction, each coupled to one Geiger Mode Avalanche Photodiode (G-APD) array. To derive the axial coordinate, Wave Length Shifter (WLS) strips are mounted orthogonally and interleaved between the crystals. The light from the WLS strips is read by custom-made G-APDs. The weighted mean of the signals in the WLS strips has proven to give very precise axial resolution. The achievable resolution along the three axes is mainly driven by the dimensions of the LYSO crystals and WLS strips. This concept is inherently free of parallax errors. Furthermore, it will allow identification of Compton interactions in the detector and for reconstruction of a fraction of them, which is expected to enhance imag...

Braem, A; Séguinot, J; Dissertori, G; Djambazov, L; Lustermann, W; Nessi-Tedaldi, F; Pauss, F; Schinzel, D; Solevi, P; Lacasta, C; Oliver, J F; Rafecas, M; De Leo, R; Nappi, E; Vilardi, I; Chesi, E; Cochran, E; Honscheid, K; Kagan, H; Rudge, A; Smith, S; Weilhammer, P; Johnson, I; Renker, D; Clinthorne, N; Huh, S; Bolle, E; Stapnes, S; Meddi, F

2009-01-01

340

Parametric model for the 3D reconstruction of individual fovea shape from OCT data.  

Science.gov (United States)

As revealed by optical coherence tomography (OCT), the shape of the fovea may vary greatly among individuals. However, none of the hitherto available mathematical descriptions comprehensively reproduces all individual characteristics such as foveal depth, slope, naso-temporal asymmetry, and others. Here, a novel mathematical approach is presented to obtain a very accurate model of the complete 3D foveal surface of an individual, by utilizing recent developments in OCT. For this purpose, a new formula was developed serving as a simple but very flexible way to represent a given fovea. An extensive description of the used model parameters, as well as, of the complete method of reconstructing a foveal surface from OCT data, is presented. Noteworthy, the formula analytically provides characteristic foveal parameters and thus allows for extensive quantification. The present approach was verified on 432 OCT scans and has proved to be able to capture the whole range of asymmetric foveal shapes with high accuracy (i.e. a mean fit error of 1.40 ?m). PMID:24291205

Scheibe, Patrick; Lazareva, Anfisa; Braumann, Ulf-Dietrich; Reichenbach, Andreas; Wiedemann, Peter; Francke, Mike; Rauscher, Franziska Georgia

2014-02-01

 
 
 
 
341

Robust anisotropic diffusion prior with anatomical regularization for 3D SPECT reconstruction  

International Nuclear Information System (INIS)

In this study, we aim at reconstructing single photon emission computed tomography (SPECT) images with the employment of available anatomical data. We use an anatomically weighted anisotropic median diffusion filter (AWAMDF) as a regularization term in a maximum a posteriori (MAP) framework. In the proposed method, co-registered data from magnetic resonance (MR) is embedded directly into the robust diffusion update equation to encourage anatomically adaptive local diffusion flow and noise suppression. The main aim of this study is to present a possible way to determine pathological tissues, such as hot and cold lesions, apparent only on emission data, while preserving edges from the anatomical image. Aiming to detect boundaries on highly distorted data, we use a Tukey's Biweight error norm in the framework of robust diffusion with a special constraint on the local gradient. Quantitative assessment of AWAMDF is performed using simulated 3D SPECT/MR data, and compared with Bowsher prior. AWAMDF outperforms BP quantitatively for damaged brain areas, and with slightly inferior variance for the whole gray matter region. (orig.)

2011-07-11

342

AX-PET: A novel PET detector concept with full 3D reconstruction  

International Nuclear Information System (INIS)

We describe the concept and first experimental tests of a novel 3D axial Positron Emission Tomography (PET) geometry. It allows for a new way of measuring the interaction point in the detector with very high precision. It is based on a matrix of long Lutetium-Yttrium OxyorthoSilicate (LYSO) crystals oriented in the axial direction, each coupled to one Geiger Mode Avalanche Photodiode (G-APD) array. To derive the axial coordinate, Wave Length Shifter (WLS) strips are mounted orthogonally and interleaved between the crystals. The light from the WLS strips is read by custom-made G-APDs. The weighted mean of the signals in the WLS strips has proven to give very precise axial resolution. The achievable resolution along the three axes is mainly driven by the dimensions of the LYSO crystals and WLS strips. This concept is inherently free of parallax errors. Furthermore, it will allow identification of Compton interactions in the detector and for reconstruction of a fraction of them, which is expected to enhance image quality and sensitivity. We present the results of proof-of-principle tests and qualification measurements of the various components prepared to build a larger scale demonstrator consisting of two matrices of 8x6 LYSO crystals and 312 WLS strips.

2009-10-21

343

Reconstructed 3D flame structures in noise-controlled swirl-stabilized combustor  

Energy Technology Data Exchange (ETDEWEB)

Flame structures of turbulent premixed flames in a noise-controlled, swirl-stabilized combustor are investigated to clarify the mechanism of combustion noise reduction by the secondary fuel injection. Planar laser-induced fluorescence (PLIF) is conducted for several cases with different secondary fuel injection, and 3D flame structure is reconstructed from PLIF results on multiple planes. The secondary fuel injection suppresses the fluctuation of high-temperature gas in the recirculation zone and reduces Reynolds stress and entropy terms in the acoustic sound source. In the flame zone, effects of the injection frequency are discussed by introducing mean progress variable. The flame brush is very wide for the no control case, whereas it becomes thin and is confined to a narrow space for the secondary fuel injection cases. The investigated combustor gives minimum sound level at a relevant fuel injection frequency, which is very low compared with the natural acoustic mode of the combustor. The flame brush becomes very thin, and self-induced oscillations of the flame brush disappear at this relevant frequency. The oscillation of the flame brush represents large-scale fluctuation of the mean heat release rate. The relations between characteristics of flame brush and combustion noise are discussed by introducing instantaneous and dynamical effects of flame front on the entropy term of the sound source. The secondary fuel injection works for the control of the entropy term in the sound source because the thin flame brush represents suppression of the instantaneous and dynamical effects. (orig.)

Tanahashi, Mamoru; Inoue, Shohei; Shimura, Masayasu; Taka, Shohei; Miyauchi, Toshio [Tokyo Institute of Technology, Department of Mechanical and Aerospace Engineering, Tokyo (Japan); Choi, Gyung-Min [Pusan National University, School of Mechanical Engineering, College of Engineering, Busan (Korea)

2008-09-15

344

3D Velocity and Density Reconstructions of the Local Universe with Cosmicflows-1  

CERN Multimedia

This paper presents an analysis of the local peculiar velocity field based on the Wiener Filter reconstruction method. We used our currently available catalog of distance measurements containing 1,797 galaxies within 3000 km/s: Cosmicflows-1. The Wiener Filter method is used to recover the full 3D peculiar velocity field from the observed map of radial velocities and to recover the underlying linear density field. The velocity field within a data zone of 3000 km/s is decomposed into a local component that is generated within the data zone and a tidal one that is generated by the mass distribution outside that zone. The tidal component is characterized by a coherent flow toward the Norma-Hydra-Centaurus (Great Attractor) region while the local component is dominated by a flow toward the Virgo Cluster and away from the Local Void. A detailed analysis shows that the local flow is predominantly governed by the Local Void and the Virgo Cluster plays a lesser role. The analysis procedure was tested against a mock c...

Courtois, Helene M; Tully, R Brent; Gottlober, Stefan

2011-01-01

345

3D RBI-EM reconstruction with spherically-symmetric basis function for SPECT rotating slat collimator  

International Nuclear Information System (INIS)

A single photon emission computed tomography (SPECT) rotating slat collimator with strip detector acquires distance-weighted plane integral data, along with the attenuation factor and distance-dependent detector response. In order to image a 3D object, the slat collimator device has first to spin around its axis and then rotate around the object to produce 3D projection measurements. Compared to the slice-by-slice 2D reconstruction for the parallel-hole collimator and line integral data, a more complex 3D reconstruction is needed for the slat collimator and plane integral data. In this paper, we propose a 3D RBI-EM reconstruction algorithm with spherically-symmetric basis function, also called 'blobs', for the slat collimator. It has a closed and spherically symmetric analytical expression for the 3D Radon transform, which makes it easier to compute the plane integral than the voxel. It is completely localized in the spatial domain and nearly band-limited in the frequency domain. Its size and shape can be controlled by several parameters to have desired reconstructed image quality. A mathematical lesion phantom study has demonstrated that the blob reconstruction can achieve better contrast-noise trade-offs than the voxel reconstruction without greatly degrading the image resolution. A real lesion phantom study further confirmed this and showed that a slat collimator with CZT detector has better image quality than the conventional parallel-hole collimator with NaI detector. The improvement might be due to both the slat collimation and the better energy resolution of the CZT detector

2004-06-07

346

Improving axial image reconstruction by off-centering ROI with data truncation and 3D weighted cone beam DBPF algorithm  

International Nuclear Information System (INIS)

We have proposed to improve the accuracy of axial image reconstruction by off-centering the region of interest (ROI) to be imaged and reconstructing the images using the 3D weighted cone beam (CB) filtered backprojection (CB-FBP) algorithm. By applying the 3D weighting scheme at each voxel within the off-centered object, the minimum cone angle of the ray out of the conjugate ray pair corresponding to the vast majority of the voxel can be effectively reduced, and thus reduce CB artifact in reconstructed image. In practice, a small to medium off-centered object, e.g., head or extremities, may readily be within the scan field of view (FOV) determined by the gantry geometry and latitudinal detector span, and accordingly the voxel-wise 3D weighted CB-FBP algorithm can be applied straightforwardly. However, it may be inevitable for a large off-centered object, e.g., the thorax embodying the heart, to be partially outside the scan FOV, which may result in severe latitudinal truncation in projection data acquisition and accordingly artifacts in reconstructed image if the FBP algorithm is employed. Recognizing the strength of derivative backprojection filtering (DBPF) algorithm in dealing with the latitudinal truncation, we propose to apply the voxel-wise 3D weighting scheme in the DBPF reconstruction. Preliminary results from the numerical simulation study demonstrate that the DBPF reconstruction algorithm can substantially reduce the artifacts caused by the latitudinal data truncation, while the voxel-wise 3D weighting can effectively suppress the CB artifacts within the off-centered ROI. (orig.)

2011-07-11

347

Atomic force microscopy imaging and 3-D reconstructions of serial thin sections of a single cell and its interior structures.  

Science.gov (United States)

The thin sectioning has been widely applied in electron microscopy (EM), and successfully used for an in situ observation of inner ultrastructure of cells. This powerful technique has recently been extended to the research field of atomic force microscopy (AFM). However, there have been no reports describing AFM imaging of serial thin sections and three-dimensional (3-D) reconstruction of cells and their inner structures. In the present study, we used AFM to scan serial thin sections approximately 60 nm thick of a mouse embryonic stem (ES) cell, and to observe the in situ inner ultrastructure including cell membrane, cytoplasm, mitochondria, nucleus membrane, and linear chromatin. The high-magnification AFM imaging of single mitochondria clearly demonstrated the outer membrane, inner boundary membrane and cristal membrane of mitochondria in the cellular compartment. Importantly, AFM imaging on six serial thin sections of a single mouse ES cell showed that mitochondria underwent sequential changes in the number, morphology and distribution. These nanoscale images allowed us to perform 3-D surface reconstruction of interested interior structures in cells. Based on the serial in situ images, 3-D models of morphological characteristics, numbers and distributions of interior structures of the single ES cells were validated and reconstructed. Our results suggest that the combined AFM and serial-thin-section technique is useful for the nanoscale imaging and 3-D reconstruction of single cells and their inner structures. This technique may facilitate studies of proliferating and differentiating stages of stem cells or somatic cells at a nanoscale. PMID:15850704

Chen, Yong; Cai, Jiye; Zhao, Tao; Wang, Chenxi; Dong, Shuo; Luo, Shuqian; Chen, Zheng W

2005-06-01

348

Atomic force microscopy imaging and 3-D reconstructions of serial thin sections of a single cell and its interior structures  

Energy Technology Data Exchange (ETDEWEB)

The thin sectioning has been widely applied in electron microscopy (EM), and successfully used for an in situ observation of inner ultrastructure of cells. This powerful technique has recently been extended to the research field of atomic force microscopy (AFM). However, there have been no reports describing AFM imaging of serial thin sections and three-dimensional (3-D) reconstruction of cells and their inner structures. In the present study, we used AFM to scan serial thin sections approximately 60 nm thick of a mouse embryonic stem (ES) cell, and to observe the in situ inner ultrastructure including cell membrane, cytoplasm, mitochondria, nucleus membrane, and linear chromatin. The high-magnification AFM imaging of single mitochondria clearly demonstrated the outer membrane, inner boundary membrane and cristal membrane of mitochondria in the cellular compartment. Importantly, AFM imaging on six serial thin sections of a single mouse ES cell showed that mitochondria underwent sequential changes in the number, morphology and distribution. These nanoscale images allowed us to perform 3-D surface reconstruction of interested interior structures in cells. Based on the serial in situ images, 3-D models of morphological characteristics, numbers and distributions of interior structures of the single ES cells were validated and reconstructed. Our results suggest that the combined AFM and serial-thin-section technique is useful for the nanoscale imaging and 3-D reconstruction of single cells and their inner structures. This technique may facilitate studies of proliferating and differentiating stages of stem cells or somatic cells at a nanoscale.

Chen Yong [College of Medicine, University of Illinois, Chicago, IL 60612 (United States) and Department of Chemistry, Jinan University, Shipai Street, Guangzhou 510632 (China)]. E-mail: drychen@uic.edu; Cai Jiye [Department of Chemistry, Jinan University, Shipai Street, Guangzhou 510632 (China)]. E-mail: tjycai@jnu.edu.cn; Zhao Tao [Department of Chemistry, Jinan University, Shipai Street, Guangzhou 510632 (China); Wang Chenxi [Department of Physics, Jinan University, Guangzhou 510632 (China); Dong Shuo [Department of BME, Capital University of Medical Sciences, Beijing (China); Luo Shuqian [Department of BME, Capital University of Medical Sciences, Beijing (China); Chen, Zheng W. [College of Medicine, University of Illinois, Chicago, IL 60612 (United States); Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA 02215 (United States)

2005-06-15

349

Atomic force microscopy imaging and 3-D reconstructions of serial thin sections of a single cell and its interior structures  

International Nuclear Information System (INIS)

The thin sectioning has been widely applied in electron microscopy (EM), and successfully used for an in situ observation of inner ultrastructure of cells. This powerful technique has recently been extended to the research field of atomic force microscopy (AFM). However, there have been no reports describing AFM imaging of serial thin sections and three-dimensional (3-D) reconstruction of cells and their inner structures. In the present study, we used AFM to scan serial thin sections approximately 60 nm thick of a mouse embryonic stem (ES) cell, and to observe the in situ inner ultrastructure including cell membrane, cytoplasm, mitochondria, nucleus membrane, and linear chromatin. The high-magnification AFM imaging of single mitochondria clearly demonstrated the outer membrane, inner boundary membrane and cristal membrane of mitochondria in the cellular compartment. Importantly, AFM imaging on six serial thin sections of a single mouse ES cell showed that mitochondria underwent sequential changes in the number, morphology and distribution. These nanoscale images allowed us to perform 3-D surface reconstruction of interested interior structures in cells. Based on the serial in situ images, 3-D models of morphological characteristics, numbers and distributions of interior structures of the single ES cells were validated and reconstructed. Our results suggest that the combined AFM and serial-thin-section technique is useful for the nanoscale imaging and 3-D reconstruction of single cells and their inner structures. This technique may facilitate studies of proliferating and differentiating stages of stem cells or somatic cells at a nanoscale

2005-06-01

350

Applying 2D ML iterative reconstruction methods with resolution recovery to 3D PET data: evaluation of rebinning effects.  

Science.gov (United States)

The applicability of OSEM reconstruction algorithms with space dependent resolution recovery to clinical FDG-PET studies is verified. The performance of the 2D algorithm is improved by means of a low resolution initialization and by a infra-iteration Metz filtering. Effects of different rebinning algorithms on 3D data are assessed, concluding that they do not alter the transaxial plane blurring parameters, thus permitting a straightforward application of 2D OSEM reconstruction after rebinning, with the same system matrix. Finally axial degradation was also quantified, finding that FORE is the best rebinning method to be combined with the 2D OSEM reconstruction. PMID:17271946

Butti, M; De Bernardi, E; Zito, F; Mainardi, L; Cerutti, S; Gerundini, P; Baselli, G

2004-01-01

351

Postoperative assessment of surgical results using three dimensional surface reconstruction CT (3D-CT) in a craniofacial anomaly  

International Nuclear Information System (INIS)

In 1983, Michael W. Vannier and Jeffrey L. Marsh developed a computer method that reconstructs three dimensional (3D) born and soft tissue surfaces, given a high resolution CT scan-series of the facial skeleton. This method has been applied to craniofacial anomalies, basal encephaloceles, and musculoskeletal anomalies. In this study, a postoperative assessment of the craniofacial surgical results has been accomplished using this 3D-CT in 2 children with craniofacial dysmorphism. The authors discuss the advantages of this 3D-CT imaging method in the postoperative assessments of craniofacial anomalies. Results are detailed in the following listing : 1) a postoperative 3D-CT reveals the anatomical details corrected by the craniofacial surgery more precisely and stereographically than conventional radiological methods ; 2) secondary changes of the cranium after the surgery, such as bony formation in the area of the osteotomy and postoperative asymmetric deformities, are detected early by the 3D-CT imaging technique, and, 3) 3D-CT mid-sagittal and top axial views of the intracranial skull base are most useful in postoperative assessments of the surgical results. Basesd on our experience, we expect that three dimensional surface reconstructions from CT scans will become to be used widely in the postoperative assessments of the surgical results of craniofacial anomalies. (author)

1988-01-01

352

Evaluation of OS-EM vs. ML-EM for 1D, 2D and fully 3D SPECT reconstruction  

International Nuclear Information System (INIS)

For SPECT reconstruction, iterative Maximum Likelihood Expectation Maximization (ML-EM) estimation has a huge computational burden. The objective of this paper is to compare images obtained by ML-EM and an EM algorithm acting on Ordered Subsets of projections (OS-EM). Two digital phantoms, a cylinder with two cold spots and an ellipsoid with several hot spots and one cold spot were reconstructed from 120 simulated noisy projections. 1D (?-like point source response), 2D (single slice response) and fully 3D reconstruction were investigated. Three quantities were calculated for the evaluation, viz. contrast, normalized standard deviation and mean squared error. In the case of fully 3D reconstruction, OS-EM 60 reconstructions (i.e., using 60 ordered subsets) were very close to ML-EM reconstructions. This shows that the OS-EM algorithm is an extremely fast and efficient method to accelerate iterative SPECT reconstruction with speed-up factors of close to half the number of projections

1996-06-01

353

A software-based x-ray scatter correction method for breast tomosynthesis  

International Nuclear Information System (INIS)

Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients. Methods: A Monte Carlo (MC) simulation of x-ray scatter, with geometry matching that of the cranio-caudal (CC) view of a DBT clinical prototype, was developed using the Geant4 toolkit and used to generate maps of the scatter-to-primary ratio (SPR) of a number of homogeneous standard-shaped breasts of varying sizes. Dimension-matched SPR maps were then deformed and registered to DBT acquisition projections, allowing for the estimation of the primary x-ray signal acquired by the imaging system. Noise filtering of the estimated projections was then performed to reduce the impact of the quantum noise of the x-ray scatter. Three dimensional (3D) reconstruction was then performed using the maximum likelihood-expectation maximization (MLEM) method. This process was tested on acquisitions of a heterogeneous 50/50 adipose/glandular tomosynthesis phantom with embedded masses, fibers, and microcalcifications and on acquisitions of patients. The image quality of the reconstructions of the scatter-corrected and uncorrected projections was analyzed by studying the signal-difference-to-noise ratio (SDNR), the integral of the signal in each mass lesion (integrated mass signal, IMS), and the modulation transfer function (MTF). Results: The reconstructions of the scatter-corrected projections demonstrated superior image quality. The SDNR of masses embedded in a 5 cm thick tomosynthesis phantom improved 60%-66%, while the SDNR of the smallest mass in an 8 cm thick phantom improved by 59% (p < 0.01). The IMS of the masses in the 5 cm thick phantom also improved by 15%-29%, while the IMS of the masses in the 8 cm thick phantom improved by 26%-62% (p < 0.01). Some embedded microcalcifications in the tomosynthesis phantoms were visible only in the scatter-corrected reconstructions. The visibility of the findings in two patient images was also improved by the application of the scatter correction algorithm. The MTF of the images did not change after application of the scatter correction algorithm, indicating that spatial resolution was not adversely affected. Conclusions: Our software-based scatter correction algorithm exhibits great potential in improving the image quality of DBT acquisitions of both phantoms and patients. The proposed algorithm does not require a time-consuming MC simulation for each specific case to be corrected, making it applicable in the clinical realm.

2011-12-01

354

Workflows and the Role of Images for Virtual 3d Reconstruction of no Longer Extant Historic Objects  

Science.gov (United States)

3D reconstruction technologies have gained importance as tools for the research and visualization of no longer extant historic objects during the last decade. Within such reconstruction processes, visual media assumes several important roles: as the most important sources especially for a reconstruction of no longer extant objects, as a tool for communication and cooperation within the production process, as well as for a communication and visualization of results. While there are many discourses about theoretical issues of depiction as sources and as visualization outcomes of such projects, there is no systematic research about the importance of depiction during a 3D reconstruction process and based on empirical findings. Moreover, from a methodological perspective, it would be necessary to understand which role visual media plays during the production process and how it is affected by disciplinary boundaries and challenges specific to historic topics. Research includes an analysis of published work and case studies investigating reconstruction projects. This study uses methods taken from social sciences to gain a grounded view of how production processes would take place in practice and which functions and roles images would play within them. For the investigation of these topics, a content analysis of 452 conference proceedings and journal articles related to 3D reconstruction modeling in the field of humanities has been completed. Most of the projects described in those publications dealt with data acquisition and model building for existing objects. Only a small number of projects focused on structures that no longer or never existed physically. Especially that type of project seems to be interesting for a study of the importance of pictures as sources and as tools for interdisciplinary cooperation during the production process. In the course of the examination the authors of this paper applied a qualitative content analysis for a sample of 26 previously published project reports to depict strategies and types and three case studies of 3D