نتایج جستجو برای: forward and back projection

تعداد نتایج: 16861423  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده ادبیات و علوم انسانی 1388

abstract: the present thesis includes ; one preface and 11speeches , that each speech considered in different researches . the prefact part , studied grammer back ground , the first speech considered a brief description about grammatical credits . the second speech considered the different typs of sentences , from structure and meaning points of view . the third speech considered the verb es...

Journal: :iranian journal of nuclear medicine 2011
faraz kalantari hossein rajabi mohsen saghari alireza emami ardekani

introduction: monte carlo (mc) is the most common method for simulating virtual spect projections. it is useful for optimizing procedures, evaluating correction algorithms and more recently image reconstruction as a forward projector in iterative algorithms; however, the main drawback of mc is its long run time. we introduced a model based method considering the effect of body attenuation and i...

ژورنال: پژوهش های ریاضی 2020

‎I‎n this paper‎, ‎a‎ forward-‎b‎ackward projection algorithm is considered for finding zero points of the sum of two operators‎ ‎in Hilbert spaces‎. ‎The sequence generated by algorithm converges strongly to the zero point of the sum of an $alpha$-inverse strongly‎ ‎monotone operator and a maximal monotone operator‎. ‎We apply the result for solving the variational inequality problem, fixed po...

2007
Yao Xie

Forward projectors are needed for iterative image reconstruction algorithms for CT or PET image reconstruction. The major cost of iterative reconstruction algorithms is computing the forward and backward projections. Conventionally, this is done in the image domain as computing the lengths of intersections between each X-ray ray and each image voxel. These operations are the major computational...

2009
Yong Long Jeffrey A. Fessler James M. Balter

The computation burden of cone-beam forward and back-projectors is one of the greatest challenges facing iterative methods for 3D image reconstruction in CT. This paper describes a new separable footprint (SF) projector. It takes advantage of small polar angles of X-rays in cone-beam geometry to approximate the voxel footprint functions as 2D separable functions with simple rectangular function...

Journal: :Signal Processing 2021

Forward scanning SAR (FS-SAR) has recently been presented as a new mode of imaging for automotive radars, providing enhanced azimuth resolution. FS-SAR extended to moving objects. However, it is assumed that the radar motion pre-compensated. Therefore, image reconstruction and focusing have deal with movement target objects only. In practice, not easy compensate for, especially, complex motion,...

2010
Yong Long Jeffrey A. Fessler

The greatest impediment to practical adoption of iterative methods for X-ray CT is the computation burden of cone-beam forward and back-projectors. Moreover, forward and back-projector accuracy is also crucial to iterative reconstruction methods. We previously described a computationally efficient projector that approximates the voxel footprint functions by the 2D separable products of trapezoi...

Journal: :CoRR 2011
S. P. Khandait Ravindra C. Thool P. D. Khandait

In this paper, an approach to the problem of automatic facial feature extraction from a still frontal posed image and classification and recognition of facial expression and hence emotion and mood of a person is presented. Feed forward back propagation neural network is used as a classifier for classifying the expressions of supplied face into seven basic categories like surprise, neutral, sad,...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده فنی مهندسی 1389

the poor orientation of the restaurants toward the information technology has yet many unsolved issues in regards to the customers. one of these problems which lead the appeal list of later, and have a negative impact on the prestige of the restaurant is the case when the later does not respond on time to the customers’ needs, and which causes their dissatisfaction. this issue is really sensiti...

Journal: :Journal of Science Communication 2015

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