Sharif Digital Repository

The main purpose of the thesis is Digital image Processing using the sparsity of image. The issue could be described in two ways. First is reconstruction of missed blocks of an image based on the sparsity of image in the transform domain and second is impulsive noise removal using the sparsity of noise in the spatial domain. In the first approach we will review Guleryuz method and simulate and analyze it. In the second approach, two new methods named RDE and Knockout will be introduced. These methods try two remove the impulsive noise of an image using its sparseness. RDE method is a development of conventional methods, but Knockout has a completely new idea. We will show that Knockout is... 

Split Hopkinson pressure bar (SHPB) test is one of the tests used for characterizing the mechanical behavior of materials at high strain rates between and s -1. A SHPB test consists of a gas gun, a striker bar, an incident bar, a transmission bar and a specimen which is sandwiched between the incident and transmission bars. In order to achieve constant strain rate during the test which is necessary in SHPB test, the incident pulse should obey the stress-strain curve of the specimen. For shaping the incident pulse usually a thin deformable disk -called pulse shaper- is placed between the striker and incident bars. In this thesis, first we designed, implemented and calibrated the measuring... 

The brain-computer interface is an advanced technology in human-machine interaction. The Speller system is a typical use of BCI, in which the target stimulation is detected by the induced signal in the brain. The most commonly speller system, the matrix Speller, has a major disadvantage, and it is Gaze-dependent. Research has proven that target-character selection in the matrix Speller is dependent on eye movement, or as referred to in technical terminology, it is gaze dependent. Therefore, the Speller matrix is not usable for users suffering from unimpaired oculomotor control. Many researchers attempted to overcome this issue, and their results led to two solutions; 1) changing the type of... 

With quick development of inexpensive video acquisition tools, fast progress of digital technology and growing availability of video editing software tools, editing and tampering of video signal has become easy and straightforward. This fact highlights the need for tools and methods that recover the editing history of digital data which has, for instance, motivated a joint project between several European universities and institutions called REWIND. Our main goal in this thesis is the blind (partial) detection of editing history for video signals without access to the original signal. The video is processed in the acquisition, coding and editing phases. Our focus in this thesis is on the... 

Image compression is a noteworthy problem in image processing field. Transform coding provides a scheme to confront the image compression problem. The discrete cosine transform (DCT) is used in the majority of image compression standards by transform coding. The DCT can efficiently represent smooth signals, but it becomes inefficient when the image contains arbitrary-shaped discontinuities. As an example, piecewise-smooth images (i.e., an image that contains multiple smooth areas separated with arbitrary-shaped boundaries), which are widely used in 3-dimensional image representation, cannot well represent by the DCT. Therefore, replacing the DCT with an adaptive transform can improve image... 

Blind source separation methods such as independent component analysis (ICA) and second order blind identification (SOBI) have shown considerable potential in the area of ambient vibration system identification. The objective of these methods is to separate the modal responses, or sources, from the measured output responses, without the knowledge of excitation. Several frequency domain and time domain methods have been proposed and successfully implemented in the literature. Whereas frequency-domain methods pose several challenges typical of dealing with signals in the frequency-domain, popular time domain methods such as NExT/ERA and SSI pose limitations in dealing with noise, low sensor... 

The objective of this project is to consider the various methods employed in processing the EMG signal to control an artificial hand. The current presented methods of EMG processing do not benefit from the fact that sequential movements are closely correlated. Using this time correlation we are going to improve the correctness of the prediction of movements. To find the application of this project in commercial artificial hand we focus on one DOF hand for a high level of accuracy. Using this processing method combined with an artificial hand having Geometric Adaptability may present an acceptable product for commercial use.

 

In this research, the ability of artificial intelligence to improve the biosensor performance of a microfluidic system has been investigated. Coulter counter is a microfluidic system that measures the concentration of particles in a fluid using signals obtained from a biosensor. The method of this system is called " Resistive Pulse Sensing (RPS)" method. The pulses in the Coulter counter signals are affected by the number, shape, size and speed of particles passing through the orifice. The pulse of two particles of the same size and different shape in these systems are very similar and this makes it difficult for an operator to distinguish the type of particle. Another disadvantage of...