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three-dimensional-imaging
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Reconstruction of 3D Images in Integral Imaging by Using Fourier Optics
, M.Sc. Thesis Sharif University of Technology ; Mehrany, Khashayar (Supervisor)
Abstract
In this thesis, the unwanted effects of diffraction and defocus aberration in three-dimensional (3D) integral imaging are taken into account by using the principles of Fourier optics approach. First, the indirect reconstruction of 3D images is simulated by using the geometrical optics and then the direct reconstruction process is simulated via Fourier optics. The role of diffraction and defocus aberration in deterioration of the depth of field is studied for both real/virtual and focused modes of integral imaging. The extent of image deterioration in 3D integral imaging is compared against the extent of deterioration in conventional single lens imaging. The field of view of the 3D integral...
Fourier optics approach in evaluation of the diffraction and defocus aberration in three-dimensional integral imaging
, Article Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III - Proceedings of the International Symposium, CompIMAGE 2012 ; 2012 , Pages 81-84 ; 9780415621342 (ISBN) ; Kavehvash, Z ; Mehrany, K ; Sharif University of Technology
CRC
2012
Abstract
The unwanted effects of diffraction and defocus aberration in three-dimensional integral imaging are taken into account by using the Fourier optics approach. The concepts of point spread function and optical transfer function widely in use for conventional two-dimensional imaging are generalized and applied to three-dimensional integral imaging systems. The effects of diffraction and defocus aberration are then studied and the performance of the conventional single lens imaging system is compared against that of the integral imaging
A surface registration technique for estimation of 3-D kinematics of joints
, Article Studies in Health Technology and Informatics, 19 January 2009 through 22 January 2009 ; Volume 142 , 2009 , Pages 204-206 ; 09269630 (ISSN) ; 9781586039646 (ISBN) ; Jafari, A ; Farahmand, F ; Sharif University of Technology
Abstract
This study proposes a new technique for registration of complicated freeform surfaces. The relationship between the initial and transferred location/orientation of a points cloud is formulated and then generalized within the framework of the influence surface modeling approach using least squares method. Results of case studies for estimation of the transformation matrix of articular surface of the knee joint in two scenes of MR images indicated high accuracies of ±1 mm and ±1 degree
Human detection in occluded scenes through optically inspired multi-camera image fusion
, Article Journal of the Optical Society of America A: Optics and Image Science, and Vision ; Volume 34, Issue 6 , 2017 , Pages 856-869 ; 10847529 (ISSN) ; Kavehvash, Z ; Aghajan, H ; Sharif University of Technology
Abstract
In this paper, a novel approach for foreground extraction has been proposed based on a popular three-dimensional imaging technique in optics, called integral imaging. In this approach, multiple viewpoint images captured from a three-dimensional scene are used to extract range information of the scene and effectively extract an object or a person, even in the presence of heavy occlusion. The algorithm consists of two parts: depth estimation and reconstruction of the targeted object at the estimated depth distance. Further processing of the resulting reconstructed image can lead to the detection of a face or a pedestrian in the scene, which may not otherwise be detectable due to partial...
Optimizing the Balance Between Resolution, Field-of-View and Depth-of-field in Three-dimensional Imaging
, Ph.D. Dissertation Sharif University of Technology ; Mehrany, Khashayar (Supervisor) ; Bagheri, Saeed (Supervisor) ; Massoumian, Farnaz (Co-Advisor)
Abstract
In this thesis a rigorous approach toward systematic quantification of qualitative fea-tures in a three-dimensional (3D) integral imaging is proposed. Incorporating the concepts of sampling rays and sampling points, the first approach is based on geo-metrical optics and quantifies the lateral and depth resolutions of the system within the field-of-view (FOV) and depth-of-field (DOF). The obtained results are justified through experiments. In the next step, the principals of wave optics are employed to measure the lateral and depth resolutions of the system. To this end, the concept of point-spread function is generalized to three-dimensional imaging systems. Through this systematic approach the...
Study and Analysis of the Amount of Three-Dimensional Image Resolution Improvement Achievable By Incoherent Holography
, M.Sc. Thesis Sharif University of Technology ; Mehrani, Khashayar (Supervisor) ; Kavehvash, Zahra (Supervisor)
Abstract
New technologies for three-dimensional (3D) sensing and visualization of real-world objects have been pursued by scientists and engineers for many decades. As opposed to traditional two-dimensional (2D) imaging techniques, 3D imaging technologies can potentially capture the 3D structure, range, and texture information of objects. Therefore, it can be developed for many applications, as medical imaging and diagnosis, dentistry, industrial designs, architecture and security. There are many 3D imaging technologies, such as holography, incoherent holography and integral imaging. Since holographic methods are based on the wave interferometry of two coherent beams, they demand high stability of...
Effects of Microstructure and Salinity Concentration on Hydraulic Conductivity of Silty Clay Soils
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
Various contaminants and their leachate, when they penetrate into the soil, cause changes in soil microstructure, this change in microstructure leads to changes in soil permeability and volume. In this study, first, the effects of soil microstructure change on the hydraulic conductivity of saturated soil were investigated using the change in initial saturation degree during compaction for compacted samples and the change in sample construction in reconstituted samples. Also, the simultaneous effect of changing the initial microstructure and salt solution on the hydraulic conductivity of saturated silty clay soils using a three-axial permeability device with the ability to measure volume...
Multimodal Image Registration using Reinforcement Learning-based Methods
, M.Sc. Thesis Sharif University of Technology ; Fatemizadeh, Emadeddin (Supervisor)
Abstract
Image registration is the process of estimating and applying a spatial transformation to a moving image with the aim of spatially aligning it with a fixed image. This allows for the combination of images with complementary information, such as images with different modalities, acquisition times, and even coming from separate individuals, with the purpose of producing more information-rich results. Image registration is a crucial step in many medical applications, such as analyzing the growth and changes of tissue and tumors, preoperative planning, image-guided surgery, radiation therapy planning and various segmentation tasks. Reinforcement learning is a science and mathematical paradigm for...
A meshless EFG-based algorithm for 3D deformable modeling of soft tissue in real-time
, Article Studies in Health Technology and Informatics, 9 February 2012 through 11 February 2012 ; Volume 173 , February , 2012 , Pages 1-7 ; 09269630 (ISSN) ; 9781614990215 (ISBN) ; Farahmand, F ; Durali, M ; Sharif University of Technology
2012
Abstract
The meshless element-free Galerkin method was generalized and an algorithm was developed for 3D dynamic modeling of deformable bodies in real time. The efficacy of the algorithm was investigated in a 3D linear viscoelastic model of human spleen subjected to a time-varying compressive force exerted by a surgical grasper. The model remained stable in spite of the considerably large deformations occurred. There was a good agreement between the results and those of an equivalent finite element model. The computational cost, however, was much lower, enabling the proposed algorithm to be effectively used in real-time applications
Spatial frequency multiple access technique in three-dimensional integral imaging
, Article IEEE/OSA Journal of Display Technology ; Volume 8, Issue 3 , March , 2012 , Pages 138-144 ; 1551319X (ISSN) ; Mehrany, K ; Bagheri, S ; Sharif University of Technology
Abstract
The trade-off between the aliasing in integral imaging (II) and the level of interference among adjacent elemental images is mathematically studied in this paper. It is then shown that the multiple-access techniques successfully used in communication systems, e.g. frequency-division multiple access (FDMA), canbeinvoked to ease the trade-off. Implementation of spatial FDMA technique in three-dimensional II is discussed together with its nonidealities and limitations. Elemental images of three toy cars and their corresponding three-dimensional image are finally provided to demonstrate the superiority of the here-proposed spatial FDMA technique
Individual virtual phantom reconstruction for organ dosimetry based on standard available phantoms
, Article Iranian Journal of Radiation Research ; Volume 7, Issue 4 , 2010 , Pages 201-206 ; 23223243 (ISSN) ; Aghaeizadeh Zoroofi, R ; Tehrani Fard, A. A ; Akhlaghpoor, S ; Chen, Y. W ; Sato, Y ; Sharif University of Technology
Novim Medical Radiation Institute
2010
Abstract
Background: In nuclear medicine application often it is required to use computational methods for evaluation of organ absorbed dose. Monte Carlo simulation and phantoms have been used in many works before. The shape, size and volume in organs are varied, and this variation will produce error in dose calculation if no correction is applied. Materials and Methods: A computational framework for constructing individual phantom for dosimetry was performed on five liver CT scan data sets of Japanese normal individuals. The Zubal phantom was used as an original phantom to be adjusted by each individual data set. This registration was done by Spherical Harmonics (SH) and Thin-Plate Spline methods....
Three-dimensional reconstruction of heavily occluded pedestrians using integral imaging
, Article 10th International Conference on Distributed Smart Cameras, ICDSC 2016, 12 September 2016 through 15 September 2016 ; Volume 12-15-September-2016 , 2016 , Pages 1-7 ; 9781450347860 (ISBN) ; Aghajan, H ; Kavehvash, Z ; CEA; Univ. Bourgogne Franche-Comte; University Blaise Pascal ; Sharif University of Technology
Association for Computing Machinery
Abstract
In this paper, we propose a novel approach for handling the occlusion problem in pedestrian detection through optical principles. Our proposed framework is based on a popular three-dimensional imaging technique in optics, named integral imaging, in which multiple viewpoint images captured from a three-dimensional scene are used to extract range information of the scene. The proposed approach effectively reconstructs an unobstructed view of heavily occluded pedestrians simultaneously containing range information. The range information provided by our method can be used for foreground extraction and the reconstruction output can be used in various applications, such as people detection and...
Robotic assisted reduction of femoral shaft fractures using stewart platform
, Article Studies in Health Technology and Informatics, 19 January 2009 through 22 January 2009 ; Volume 142 , 2009 , Pages 177-179 ; 09269630 (ISSN) ; 9781586039646 (ISBN) ; Kazemirad, S ; Farahmand, F ; Sharif University of Technology
Abstract
A robotic system with 6 DOF mobility was proposed for reduction of femoral shaft fractures based on Stewart platform. A plan for implementing the platform on bone fragments was introduced and a step by step strategy for performing the reduction procedure, based on the system's inverse kinematic solution, was proposed. The efficacy of the system was evaluated in some case studies and it was shown that it can be locked to act as an external fixator
Classification of normal and diseased liver shapes based on spherical harmonics coefficients
, Article Journal of Medical Systems ; Vol. 38, issue. 5 , April , 2014 ; ISSN: 01485598 ; Zoroofi, R. A ; Tehrani-Fard, A. A ; Akhlaghpoor, S ; Sato, Y ; Sharif University of Technology
Abstract
Liver-shape analysis and quantification is still an open research subject. Quantitative assessment of the liver is of clinical importance in various procedures such as diagnosis, treatment planning, and monitoring. Liver-shape classification is of clinical importance for corresponding intra-subject and inter-subject studies. In this research, we propose a novel technique for the liver-shape classification based on Spherical Harmonics (SH) coefficients. The proposed liver-shape classification algorithm consists of the following steps: (a) Preprocessing, including mesh generation and simplification, point-set matching, and surface to template alignment; (b) Liver-shape parameterization,...
A novel model for three-dimensional imaging using interferometric ISAR in any curved target flight path
, Article IEEE Transactions on Geoscience and Remote Sensing ; Vol. 52, issue. 6 , 2014 , pp. 3236-3245 ; ISSN: 01962892 ; Bastani, M. H ; Sharif University of Technology
Abstract
Using a second receiver antenna close to the main transceiver antenna of inverse synthetic aperture radar (ISAR), it is possible to find 3-D positions of target scattering points. Such system is called bistatic, monopulse, or interferometric ISAR (InISAR). In the conventional model of ISAR, the unknown flying object should have a linear trajectory, and only small deviations from this trajectory can be compensated. Target motions which are highly nonlinear or curvy cannot be used in the conventional model. In this paper, we propose a new model for InISAR to process all collected data from the target, regardless of the form of the flight path. More accuracy is achieved for 3-D positioning of...
3D calculation of absorbed dose for 131I-targeted radiotherapy: A monte carlo study
, Article Radiation Protection Dosimetry ; Volume 150, Issue 3 , October , 2012 , Pages 298-305 ; 01448420 (ISSN) ; Sarkar, S ; Abbaspour Tehrani Fard, A ; Ay, M. R ; Khosravi, H. R ; Loudos, G ; Sharif University of Technology
2012
Abstract
Various methods, such as those developed by the Medical Internal Radiation Dosimetry (MIRD) Committee of the Society of Nuclear Medicine or employing dose point kernels, have been applied to the radiation dosimetry of 131I radionuclide therapy. However, studies have not shown a strong relationship between tumour absorbed dose and its overall therapeutic response, probably due in part to inaccuracies in activity and dose estimation. In the current study, the GATE Monte Carlo computer code was used to facilitate voxel-level radiation dosimetry for organ activities measured in an . 131I-treated thyroid cancer patient. This approach allows incorporation of the size, shape and composition of...
On limits of embedding in 3D images based on 2D Watson's model
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 1 October 2010 through 3 October 2010 ; Volume 6526 LNCS , October , 2011 , Pages 293-304 ; 03029743 (ISSN); 9783642184048 (ISBN) ; Ghaemmaghami, S ; Sharif University of Technology
2011
Abstract
We extend the Watson image quality metric to 3D images through the concept of integral imaging. In the Watson's model, perceptual thresholds for changes to the DCT coefficients of a 2D image are given for information hiding. These thresholds are estimated in a way that the resulting distortion in the 2D image remains undetectable by the human eyes. In this paper, the same perceptual thresholds are estimated for a 3D scene in the integral imaging method. These thresholds are obtained based on the Watson's model using the relation between 2D elemental images and resulting 3D image. The proposed model is evaluated through subjective tests in a typical image steganography scheme
A new model of pressure propagation in human tissue in HIFU application
, Article Acta Medica Mediterranea ; Volume 31, Issue 7 , 2015 , Pages 1501-1505 ; 03936384 (ISSN) ; Abbaspour Tehrani Fard, A ; Pouladian, M ; Hemmasi, G. R ; Sharif University of Technology
A. CARBONE Editore
2015
Abstract
This project is a new pressure model for propagating pressure inside one or several tissues at the time of treatment with high intensity focus ultrasound (HIFU). Pressure's changes are converted to heat's changes in tissue and this is done oscillatory. When the treatment is done in deeper tissues, obtained heat can affect surficial tissues. This pressure effect also can enter surficial tissues. Amount of pressure and heat possible injury can be controlled and reduced through this mechanical modelling. In this model we have used three layers and pressure also is obtained within these three layers and is investigated averagely. Obtained tissue in this mood is kidney tissue and it is tried to...
Extension of depth of field using amplitude modulation of the pupil function for bio-imaging
, Article Proceedings of SPIE - The International Society for Optical Engineering, 6 April 2010 through 8 April 2010 ; Volume 7690 , May , 2010 ; 0277786X (ISSN) ; 9780819481542 (ISBN) ; Bagheri, S ; Mehrany, K ; Javidi, B ; Sanchez, E ; Martinez Corral, M ; Sharif University of Technology
2010
Abstract
In this paper we present a novel approach to generate images of extended depth of field (DOF) without compromising the lateral resolution to support realization of three-dimensional imaging systems such as integral imaging. In our approach in extending DOF, we take advantage of the spatial frequency spectrum of the object specific to the task in hand. The pupil function is thus engineered in such a fashion that the modulation transfer function (MTF) is maximized only in these selected spatial frequencies. We extract these high energy spatial frequencies using PCA method. The advantage of our approach is illustrated using an amplitude modulation and a phase modulation example. In these...
A computer model for evaluating the osteotomy parameters of Chiari pelvic osteotomy
, Article International Orthopaedics ; Volume 34, Issue 3 , 2010 , Pages 329-333 ; 03412695 (ISSN) ; Gouran Savadkoohi, D ; Ghadirpoor, A ; Rahimpoor, S ; Azghani, M ; Farahmand, F ; Sharif University of Technology
2010
Abstract
This study was conducted to evaluate the effect of the various osteotomy parameters on the biomechanical aspects of the hip joint on a computerised model. The data of the radiographs and a three-dimensional (3D) CT scan of six patients with coverage deficient hip joint were used to construct a 3D computer model. Then Chiari type osteotomies were simulated using various heights, angles and fibrocartilage thicknesses. A new angle called the mid acetabular center edge (MACE) angle was defined in a mid coronal CT cut. The optimum displacement for obtaining the maximum coverage averaged 73%. The angle and height of the osteotomy had a significant effect on the MACE angle (P value∈<∈0. 01). Our...