نتایج جستجو برای: Signal correction

تعداد نتایج: 575709  

The true MR signal intensity extracted from noisy MR magnitude images is biased with the Rician noise caused by noise rectification in the magnitude calculation for low intensity pixels. This noise is more problematic when a quantitative analysis is performed based on the magnitude images with low SNR(<3.0). In such cases, the received signal for both the real and imaginary components will fluc...

Journal: :نشریه دانشکده فنی 0
اردشیر گویری

sensitivity of an electromagnetic type metal detector is directly related to stability, the higher the required sensitivity, the more frequently the rebalancing controls will have to be adjusted. thus, for maximum sensitivity in the head ,the use of automatic drift compensation network is necessary in order to cancel out the signal resulting from a slow drift in the coil system due to the tempe...

Ebrahim Hajizadeh Faraz Kalantari, Hadi Taleshi Hossein Rajabi, Kourosh Ebrahim Nejad Gorgi

  Introduction: There are several technical features that make PET an ideal device for the noninvasive evaluation of cardiac physiology. Organ motion due to respiration is a major challenge in diagnostic imaging, especially in cardiac PET imaging. These motions reduce image quality by spreading the radiotracer activity over an increased volume, distorting apparent les...

Introduction: Functional MRI methods have been used to study sensorimotor processing in the Spinal cord. However, these techniques confront unwanted contributions to the measured signal from the physiological fluctuations. For the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as significant sources of noise, especi...

Faraz Kalantari, Hadi Noori Eskandari, Mohsen Hajizadeh Saffar Peter Knoll, Seyed Rasoul Zakavi Shabnam Oloomi

  Objective(s): In SPECT, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. Many techniques for attenuation and scatter correction have been proposed. An acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. Here, we propose new Maximum Likelihood Expectation Maximiz...

Journal: :iranian journal of nuclear medicine 2007
kourosh ebrahim nejad gorgi hossein rajabi ebrahim hajizadeh faraz kalantari hadi taleshi

introduction: there are several technical features that make pet an ideal device for the noninvasive evaluation of cardiac physiology. organ motion due to respiration is a major challenge in diagnostic imaging, especially in cardiac pet imaging. these motions reduce image quality by spreading the radiotracer activity over an increased volume, distorting apparent lesion size and shape and reduci...

Journal: :iranian journal of basic medical sciences 0
shabnam oloomi department of medical physics, mashhad university of medical science, mashhad, iran hadi noori eskandari department of applied mathematics, school of mathematical sciences, ferdowsi university of mashhad, mashhad, iran seyed rasoul zakavi nuclear medicine research center, imam reza hospital, faculty of medicine, mashhad university of medical sciences, mashhad, iran peter knoll department of nuclear medicine wilhelminenspital vienna, austria faraz kalantari research center for nuclear medicine, tehran university of medical sciences, tehran, iran mohsen hajizadeh saffar department of medical physics, mashhad university of medical science, mashhad, iran

objective(s): in spect, the sinogram contains scatter and lack of attenuated counts that degrade the reconstructed image quality and quantity. many techniques for attenuation and scatter correction have been proposed. an acceptable method of correction is to incorporate effects into an iterative statistical reconstruction. here, we propose new maximum likelihood expectation maximization (mlem) ...

M. R. Mosavi,

This paper presents design and implementation of three new Infrared Counter-Countermeasure (IRCCM) efficient methods using Neural Network (NN), Fuzzy System (FS), and Kalman Filter (KF). The proposed algorithms estimate tracking error or correction signal when jamming occurs. An experimental test setup is designed and implemented for performance evaluation of the proposed methods. The methods v...

Journal: :رادار 0
سید روح الله ثمره هاشمی سید علیرضا سیدین

at first, ground-based circular strip-map synthetic aperture radar (gb-csmsar) and its capabilities is introduced and the received signal model, 2-d frequency spectrum and the azimuth and range resolutions are derived and compared with the linear motion strip-map sar resolutions. because of the stability of the path and speed of antenna in gb-csmsar a frequency domain imaging algorithm is sugge...

پایان نامه :0 1374

the aim of this study has been to find answers for the following questions: 1. what is the effect of immediate correction on students pronunciation errors? 2. what would be the effect of teaching the more rgular patterns of english pronunciation? 3. is there any significant difference between the two methods of dealing with pronuciation errore, i. e., correction and the teaching of the regular ...

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