Sharif Digital Repository

Nowadays, with high performance computers and progress in video recorder devices and their related technologies, price of these devices is being balanced and recording the videos is conventional now. Processing of these videos has been a challenge in industry and science. Control and surveillance of places such as airports and roads and reducing their sizes in memory are some of their research area. Usually one of the initial preprocesses of such applications specially the object tracking is background modeling and background subtraction. This preprocess has an essential effect on the other algorithms that process based on these processes’ results. If this section conducted with fewer... 

The long term evolution (LTE) standard is introduced and developed by the 3rd generation partnership project (3GPP) based on orthogonal frequency division multiplexing (OFDM). OFDM systems, in spite of having many advantages such high performance in bandwidth usage, are very sensitive to inter carrier interference (ICI) as a drawback. In order to prevent ICI, the frequency offset, mainly caused by the miss-match between oscillators' frequency and also between the sampling frequency of the transmitter and the receiver, should be estimated and compensated. Frequency synchronization is a part of the tasks of a synchronizer. In this thesis, main tasks of a synchronizer are illustrated and... 

Increasing needs for wireless positioning systems, especially in modern wireless networks, have emerged new trends in research on local positioning systems and algorithms. In this dissertation, several geometric arrangement of positioning systems, different types of wireless measurements used for positioning, and estimation of desirable coordinate parameters based on them are investigated. The set of constrained linearized equations, by introducing intermediate variables are developed and compared with Cramer-Rao bounds. Performance bounds of ToA, TDoA and round-trip ToA systems are obtained and their sensitivity to the location changes of the target and reference stations is examined... 

The aim of tracking is localization and positioning of position-variant object through consecutive times. The essence of this object determines the application of tracking. For example this object can be the satellite, mobile, certain object in sequential movie or etc. The particle filter as an estimation filter is a method that provides us the solution of tracking Problem. Therefore this thesis is devoted to particle filter and its application in tracking. But tracking problem needs some prior information; one of them is access to measurements relating to object position. In situations that the measurement equation which is related to object position has ambiguity we need another mechanism... 

Detection and Tracking objects in various environmental conditions is a challenging task in computer vision. Abrupt changes in illumination, object size and noise level make this task even harder. Due to these problems, it is somehow impossible to propose a fully functional system for tracking every type of object. In this thesis we propose a new method for detection and tracking vehicles in traffic scenes. The problem is solved by dividing it into two parts: at First we have evaluated more than ten state-of-the art trackers, the final multi-vehicle tracker is chosen, and then, like any other object tracking method, we have used a unique identiy for each vehicle. This traffic identity is... 

By progress of computer vision, many systems are produced for soccer analysis. These systems have been used in many applications such as 2D and 3D reconstruction in arbitrary view. In this circumstance, we need to detect and track players, referee and ball in whole matches. In a single view system there are problems such as occlusion. By having more views of game, when two objects are occluded in one view, we can detect and track them in the others. Objective of this project is multi-view detection and multi-view tracking players and ball in soccer. In recorded videos from multiple views, we track path of players and the ball.
Proposed player tracking system has two main parts. First... 

The conventional bearing-only tracking solutions are based on Kalman filter. Whenever the problem equations are nonlinear, Extended Kalman Filter (EKF) or more complicated methods are used necessarily. However, EKF suffers of being biased and unstable. Here a new recursive method based on a linear modeling of the problem is proposed, the method does not need an initial guess and outperforms the Kalman filter in the terms of accuracy, complexity and stability. Furthermore, input information needed for the proposed tracking filter is just the observer position, time and value of each angle measurements and the computation load is less than even a simple EKF. mathematical analysis, as well as... 

Radio Frequency IDentification (RFID) is an increasingly important area in automatic identification. Low cost RFID tags (labels) are considered as the next generation of barcodes and their purpose is to compensate for shortcomings in computer recognition of objects using cameras. Supply chain management, access control, animal identification,e-passports along with the possibility of having e-health, e-agriculture and smart homes are few examples of RFID application developments. Despite its low cost, ubiquity, and widespread usage, RFID tags suffer from several major drawbacks, particularly information leakage and traceability. In RFID authentication protocols, both information leakage and... 

Camera calibration in sport videos has applications such as sport video analysis, insertion of virtual graphical elements, and 3D reconstruction. Our goal in this research is to fully calibrate cameras in soccer match videos. By calibration parameters, we mean the internal and the external camera parameters. We can have a mapping from world coordinates to image coordinates if we have all the calibration parameters. The cameras used in this research are stationary pan-tilt-zoom cameras. The main challenges in camera calibration are noise, blur, bad lighting conditions, lack of useful information image,fast movement of camera and radial distortion. In addition, as another challenge, we assume... 

The following thesis is concerned with the effect of channel feedback in tracking and stability of linear Gaussian systems over Additive White Gaussian Noise (AWGN) channel when the decoder is the Kalman filter and encoder is the innovation encoder. When the feedback channel is described by a noisy link or a random switch, it is shown that stability is not possible for unstable systems. But for stable systems, an innovation encoder, Kalman filter decoder and a certainly equivalent controller for tracking and stability are presented. When the feedback channel is described by a deterministic switch, for both stable and unstable systems, an innovation encoder, Kalman filter decoder and a... 

Object tracking is an important tool for video analysis which has been applied to public surveillance, road safety, and scene analysis. In multiobject tracking, the goal is to extract the trajectory of every target using spacial and temporal information. Since new objects can enter the tracking area, an object detector is required to detect their presence. This detector locates target objects in all frames and its (noisy) output is delivered to an associator that returns each object’s trajectory. The associator uses the motion and appearance model of the objects to discover their relation and find the trajectories. In this thesis, each target is partitioned into a number of non-overlapping... 

The purpose of multi target tracking, is tracking multiple target in each frame of video sequences simultaneously. Object tracking encounters many challenges. Two major challenges of tracking problem that we focus on in them in this thesis are detecting object in each frame of video sequence and handling occlusion problem. Our proposed method for multi target tracking considers one target as a main target and other targets as subsidiary targets. Proposed method track objects in initial view by Kalman filter that is adapted and tuned for multi target tracking. In case of occlusion our method uses data from auxiliary view for handling occlusion. In auxiliary view objects that are occluded in... 

Nowadays, autonomous underwater vehicles (AUVs) are implemented to carry out various activities under water. Amongst applications of these vehicles we can mention monitoring of marine creatures, mine installation and neutralization, and many military applications. The objective of this research is designing a control algorithm for underwater vehicles such that an under actuated vehicle can reckon a moving target as a reference and whilst chasing it, vehicle can keep a fixed distance from this target. First the dynamics of underwater vehicles are modeled and in this modeling different effects due to under water motion such as drag force, buoyancy force, and also added mass are included... 

Abstract: In this dissertation, the problem of tracking and stabilization of nonlinear dynamic systems over the packet erasure channel is addressed. Using the idea of linearization of nonlinear system around current working point, and by the design of an encoder, decoder, and controller for the linearized system, state tracking and reference tracking of the nonlinear system are addressed. To prove the traking and stability of the system, the strong law of large numbers and the dwell time approach are used. By computer simulations, the theoretical development is applied on the nonlinear dynamic of the unicycle model, which is a suitable model for autonomous vehicles, such as drones, unmanned... 

The purpose of this thesis is sliding mode control of a roll-pitch seeker by considering the zenith pass problem. This problem takes place when the target appears in front of the seeker’s head. First, the mathematical model of the roll and pitch frames is obtained by the Newton-Euler equations of motion. Then, a MIMO sliding mode controller is designed. The performance of the controller is investigated in the presence of model uncertainties and seeker disturbances. The results indicate that the designed controller is robust enough and provides a suitable performance in the stabilization, tracking and guidance loops.
 

Object tracking is one of the first, most basic and among the topics of interest in the field of computer vision. Nowadays, with the availability of high-quality and inexpensive video cameras and the expansion of neural networks, there has been a great interest in automatic video analysis using object tracking algorithms. However, many of the existing object tracking algorithms do frame-by-frame tracking using videos with high frame rates, which is not suitable for all locations that use surveillance cameras, because due to existing hardware limitations, the recorded videos are either kept for a limited period of time or are forcibly stored with low frame rates, which leads to the loss of a... 

In this thesis, we study the observability and stability problems of networked control systems (the control systems which communicate through communication channels) to answer two important questions about different system models. The first is that what is the constraints implied by the stability or observability of systems? (necessary condition on the observability and stability). The second is that under which constraints can we present a design for system to guarantee the observability or stability of systems? (sufficient condition on the observability and stability). Clearly, an efficient design is the one that presents a tight sufficient condition.One of system models addressed in this... 

Independent robots are equipped with various sound, inertia and visual sensors for decision making. Vision is an attractive sensor due to its non-invasive nature, passivity, and high information content. In natural environments, visual noises such as snow, rain, and dust distort images. in underwater environments, factors such as refraction and absorption of light suspended particles in the water, and color distortion affects the quality of visual data, resulting in noisy and distorted images. As a result, the autonomous underwater vehicles that rely on vision (AUVs) are challenged, resulting in poor performance. To improve the input to the visual algorithm for tracking the pipeline, in... 

Surveillance systems play an important role in the modern world. Nowadays, CCTV cameras are installed in many places to monitor various events. These cameras produce video data in a very large volume and size. One of the main challenges in this field is analyzing the content of these videos and summarizing and storing them in compressed formats such as text to save storage space. With the advancement of computing tools and the success of deep learning algorithms in solving many problems such as object detection, human action recognition and machine translation, many efforts have been made to describe video content. Most of these methods have described open domain videos and a limited number...