نتایج جستجو برای: object scatter

تعداد نتایج: 310250  

Journal: :iranian journal of medical physics 0
mohammad taghi bahreyni toossi medical physics research center, medical physics department, mashhad university of medical sciences, mashhad, iran

introduction spect projections are contaminated by scatter radiation, resulting in reduced image contrast and quantitative errors. backscatter constitutes a major part of the scatter contamination in lower energy windows. the current study is an evaluation of the effect of backscatter material on fwhm and image quality investigated by monte carlo simulation. materials and methods simind program...

Journal: :Journal of physics 2022

Abstract A scattering plate consisting of multiple lead strips is an effective tool for scatter correction and dose reduction in cone-beam CT(CBCT). Existing methods take advantage data redundancy by partially blocking cone beam from a single scan to make up perform correction. However, geometric objects with large angles during CBCT scans, existing backprojection-filteration(BPF) algorithms ca...

2009
Juan José Pantrigo Ángel Sánchez Antonio S. Montemayor Kostas Gianikellis

Visual tracking of articulated motion is a complex task with high computational costs. Because of the fact that articulated objects are usually represented as a set of linked limbs, tracking is performed with the support of a model. Model-based tracking allows determining object pose in an effortless way and handling occlusions. However, the use of articulated models generates a multidimensiona...

Journal: :Physics in medicine and biology 2016
F H Green M C Veale M D Wilson P Seller J Scuffham S Pani

In mammography, the reduction of scattered x-rays is vital due to the low contrast or small dimension of the details that are searched for. The typical method of doing so in current conventional mammography is the anti-scatter grid. The disadvantage of this method is the absorption of a proportion of the primary beam and therefore an increase in dose is required to compensate for the loss of co...

Journal: :The Journal of the Acoustical Society of America 2009
Mark Andrews Zheng Gong Purnima Ratilal

The matched filter enables imaging with high spatial resolution and high signal-to-noise ratio by coherent correlation with the expected field from what is assumed to be a discrete scatterer. In many physical imaging systems, however, returns from a large number of randomized scatterers, ranging from thousands to millions of individuals, are received together and the coherent or expected field ...

This study examined the effectiveness of guidance teachers on students’ achievement among Shahed and Isargar guidance school student in scatter plot in West Azerbaijan province in. This research method is causal-comparative. The study population consisted of all 270 Shahed and Isargar students in scatter plot in West Azerbaijan province and all 305 Shahed and Isargar students studying in guidan...

Journal: :Information Visualization 2009

Journal: :iranian journal of nuclear medicine 0
alireza sadremomtaz department of physics, faculty of science, university of guilan, rasht, iran zeinab telikani department of physics, faculty of science, university of guilan, rasht, iran

introduction: image quality and accuracy of in vivo activity quantification in spect are affected by collimator penetration and scatter components, especially in high energy imaging. these phenomena highly depend on the collimator characteristic and photon energy. the presence of penetrated and scattered photons from collimator in spect images degrades spatial resolution, contrast and image qua...

Journal: :Nuclear Physics B 1996

Ahmad Bitarafan Rajabi Bijan Hashemi Malayeri Fereidoon Rastgoo Hassan Firoozabadi Hossein Rajabi, Nahid Yaghoobi Nasrollah Jabbari

Introduction: Scatter radiation is one of the major sources of error in nuclear medicine data processing. Different methods of scatter correction have been introduced in order to improve the quality of data. However the best method is to avoid recording of scatter photons in acquisition. The only difference between scattered and non-scattered photons is the energy. Pulse height analyzer i...

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