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Similarity measures for intersection of camera view frustums
, Article Iranian Conference on Machine Vision and Image Processing, MVIP ; Volume 2017-November , 2018 , Pages 171-175 ; 21666776 (ISSN); 9781538644041 (ISBN) ; Shirzad, H ; Kasaei, S ; Sharif University of Technology
IEEE Computer Society
2018
Abstract
For a moving camera recognizing that it has seen a place before now, is one the most important issues in the 3D reconstruction problems. In these problems, the main goal is to create a three-dimensional model from a sequence of 2D captured images during different times. That part of the scene which is rendered by a camera is often modeled by a frustum. Calculating the amount of intersection of two camera view frustums at different times can help to solve this problem. However, there are two major difficulties. First, calculating the intersection of two frustums, in general, is so complicated. And second, there are some uncertainties in the moving camera parameters over time. In this paper,...
Studying soft X-Rays emitted by SUT-PF using a cylindrical bent crystal spectrometer
, Article Journal of Fusion Energy ; Volume 35, Issue 2 , 2016 , Pages 346-351 ; 01640313 (ISSN) ; Hosseinzadeh, A ; Nazmabadi, M ; Sharif University of Technology
Abstract
Plasma focus is a copious source of electrons, ions, neutrons, and X-rays. SUT-PF is a 7 kJ Mather type plasma focus device. In order to study soft X-rays emitted by this device a bent crystal spectrometer has been designed and constructed based on Johann method. Before recording spectral lines, using a photodiode detector and a pinhole camera, optimum parameters for maximum emission of soft X-rays have been studied and registered. Results show that ionized Argon atomic lines mostly have wavelengths between 3 and 4 Å. Among them 1s2–1s2p transition with a wavelength of 3.943 Å represents the most intense line
Design and Construction of a Bent Crystal Spectrometer for Studying Soft X-Rays of Sharif Plasma Focus
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Etaati, Gholam Reza (Supervisor)
Abstract
A soft X-ray spectrometer based on Johann's method and an embedded curved crystal is designed and fabricated for Sharif University of Technology's Plasma Focus (SUT-PF) in this project. Focusing rays with the same wavelength at a point to increase the ray intensity is the reason of choosing the cylindrical curved crystal spectrometer since its performance is inspired to the Bragg's law.The optimal conditions for SUT-PF (pressure and voltage) is adjusted and examined by photodiode detector and the camera pinhole before spectroscopy experiments. The diameter of generated hot spots is measured as 80 microns in the optimal condition.The recorded spectral lines on the radiography film and the...
X-ray optimization in Sharif University of Technolgy’s Plasma Focus
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Naser (Supervisor) ; Etaati, Gholamreza (Supervisor)
Abstract
In this project we studied Soft and Hard x-ray emissions from Sharif University of Technology’s Plasma Focus (SUT-PF) device filled with Argon gas. SUT-PF is a Mather type plasma focus device ( ). Our expriments have been done in various charging voltages ( ) and various filling pressures. Using different diagnostics X-ray’s intensity in each working condition (voltage and pressure) has been measured and finally these data analysed to find optimum conditions for maximum x-ray production in this device. Used diagnostics was: Rogowski coil, photodiodes combination with ultra thin metal foils, type Plastic scintillation detectors, and pinhole camera. In each shot, time resolved Rogowski coil,...
Geometrical analysis of localization error in stereo vision systems
, Article IEEE Sensors Journal ; Volume 13, Issue 11 , 2013 , Pages 4236-4246 ; 1530437X (ISSN) ; Samavi, S ; Soroushmehr, S. M. R ; Shirani, S ; Sharif University of Technology
2013
Abstract
Determining an object location in a specific region is an important task in many machine vision applications. Different parameters affect the accuracy of the localization process. The quantization process in charge-coupled device of a camera is one of the sources of error that causes estimation rather than identifying the exact position of the observed object. A cluster of points, in the field of view of a camera are mapped into a pixel. These points form an uncertainty region. In this paper, we present a geometrical model to analyze the volume of this uncertainty region as a criterion for object localization error. The proposed approach models the field of view of each pixel as an oblique...