Sharif Digital Repository

Recognizing human actions is an important and challenging topic in computer vision, which has important applications such as video surveillance and Indexing. From a computational perspective, actions can be defined as three-dimensional patterns, in space and in time which can be modeled using several representations. Action representations differ in visual information used in spatial dimensions (e.g., shape or appearance) and the representation of dynamics in time. The goal of this thesis is to develop new techniques and improve current results in action categorization. As such, using a general structure, three methods are proposed. In this structure, local spatio-temporal features are... 

Due to fast growth of wireless mobile networks, video transmission over wireless media has been widely studied. As wireless networks are error prone, there is a high possibility of loss in sent packets. Since time limitations in real-time video applications should be met, the delay- related to resending packets -is not acceptable and the error should to be concealed at receiver side. In this thesis, with respect to different concealment methods, two new methods for temporal error concealment are proposed. In the first method, an optimized set of motion vectors is formed using motion vectors in surrounding blocks of the lost macro block, and then this set is searched for the best motion... 

Panoramic radiography is known to be one of the preliminary means in diagnoses of maxillofacial intraosseos lesions, which has a big role in increasing the prognosis of such patients. Considering the fact that nowadays most health-care centers are equipped with digital radiography systems, we can rely on image processing techniques to recognize such lesions automatically.In this study, we try to segment mandible (lower jaw) out of panoramic image by means of some innovative algorithms based on edge detection and edge following, and some atlas-based methods. Then by extracting some features such as intensity, homogeneity, local energy and local gradient and with the help of SVM classifier we... 

Microcarriers (MCs) are an attractive technology with various applications in tissue engineering. In this study, chitosan/gelatin MCs were fabricated with blends of different ratio of chitosan/gelatin, by using a setup containing high voltage electrostatic field and syringe pump. Optimization of blend ratio, voltage and syringe pump flow carried out by the “Design expert” software leads to fabrication of MCs with constant diameter while having various elasticity. Mechanical strength and elasticity of MCs were determined. Human umbilical cord mesenchymal stem cells (hUCMSCs) were cultured on MCs dynamically by using mini-rocher in an incubator. Cells adhesion on MCs were successfully shown by... 

Generally, the concept of producing ‘spare parts’ of the body for replacement of damaged or lost organs lies at the core of the varied biotechnological practices referred as tissue engineering. Tissue engineering is an interdisciplinary field that incorporates principles of engineering with the life sciences. Tissue engineering is based on three principle; cells, scaffolds for cells expansion, attachment as an environment like ECM and growth factors. These things together can help tissue engineers to provide microenvironments which are suitable for special cells. The most important thing in this kind of works is the ability to simulate environment for cells the same as body. According to the... 

In general, repair and regeneration of damaged tissues or lost organ is base definition of a technology named tissue engineering. Tissue engineering technology provides innovative path to achieve better medical treatment, including different methods which manipulate natural or synthetic biomaterials mimicking stem cells environmental condition inside the body, in order to facilitate desired cell expansion and differentiation. Recently, application of cell carriers in form of microcarriers which are injectable, biodegradable and biocompatible have attracted significant attention. Due to increasing effectiveness in animal cell culture.
The aim of this work was fabrication of... 

Most broadcast stations insert their logos to claim video content ownership and/or for business purposes.This process reduces picture quality in the logo region and also causes visual discomfort to viewers. Logo detection has a variety of applications; such as automatic TV commercial removal, broadcast surveillance, and video content understanding. Video logos can be considered as a form of visible watermark. Stations may also overlay their logos over the original logo when rebroadcasting a program produced by another station. Also, most comapnies keep a giant archive of their broadcasted programs which are going to be used in their future programs. Here, we have presented an efficient... 

In this thesis we will first review the problem of deformable modeling. Due to their corss-disciplinary nature, deformable modeling techniques have been the subject of the vigorous research over the past three decades and have found numerous applications in the field of machine vision. Thus the focus will be on general deformable models for computer-based modeling which can be used for computer graphics, visualization, and various image processing applications. So the state of the art of deformable modeling is discussed. Then the focus of the thesis will be on different approaches for the problem of deformable surface reconstruction in 3D space. Amongs these methods there are two main... 

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... 

In many applications of multi view 3D reconstruction, image mosaicing is one of the most important processes. Image mosaicing is the action of stitching some pictures of a scene so that a complete picture of the scene is constructed. The proposed method is such that for PTZ cameras by extracting features from frame, the homography matrix between frames will be computed. Then by converting plane coordinate into spherical coordinate, a complete picture of the scene will be constructed and forground will be removed. For fixed cameras sufficient corresponding points will be selected for computing the homography matrix between cameras. Using the homography, the frames without forground will be... 

Image Registration is a fundamental task in numerous applications in medical image processing and is defined as the process of determining the correspondence of between images collected at different times or using different imaging modalities. This correspondence can be used for aligning images so that the pair can be directly compared, combined or analyzed. Image-guided surgery systems use registration for establishing an accurate relation between preoperative and intraoperative image space. There have been several methods for rigid registration which are not easily applicable for soft tissues. Indeed, nonrigid deformation of soft tissues will endanger the accuracy of rigid methods, so it... 

In recent years, ability of computers to recognize human actions, because of numerousapplications, has attracted scientists. Surveillancesystems in house, work and public places, human computer interaction, study of human movement problems, remote supervision of ill or old people and sport training are only some of the applications. In this thesis 10 actions are considered. These actions are Walking, Running, Galloping side, Bending, Jump jacking, Jumping, Jumping in place, Skipping, Waving one hand and Waving two hands. All actions exist in Weisemann dataset so this dataset is used as training and testing dataset. Here important objectives are recognising human action so that it is... 

Today, the material selection process plays an important role in all engineering design branches. Generally, in transition from concept design to detail design, designers and engineers need to find specific materials to optimize performance of the systems. There are introduced nearly 80000 engineering materials up to now, i.e. metallic alloys, composite materials, plastics, ceramics, glass and etc. These large amounts of materials and the wide range of manufacturing processes causes engineers always seek new material selection methods. In material selection it’s require to consider advantages, restrictions, necessities of method and this phenomenon appear because of design problem that... 

In large databases, availability of labeled training data is mostly prohibitive in classification. Semi-supervised algorithms are employed to tackle the lack of labeled training data problem. Video databases are the epitome for such a scenario; that is why semi-supervised learning has found its niche in it. Graph-based methods are a promising platform for semi-supervised video classification. Based on the multiview characteristic of video data, different features have been proposed (such as SIFT, STIP and MFCC) which can be utilized to build a graph. In this project, we have proposed a new classification method which fuses the results of manifold regularization over different graphs. Our... 

The goal of human action recognition systems is to label the sensory observation data, using one of the predefined action verbs in the system. During recent years, human action recognition has received a growing interest due to its application in automatic scene interpretation. For instance, automatic surveillance systems in public places should be able to discriminate normal and suspicious actions. Human-computer-interface (HCI) systems (which have became popular in recent years) mostly need a similar system to recognize the gesture of their users without using any keyboard (or similar input devices). Human action recognition technologies can also boost the video retrieval systems.
An... 

One major problem in sport match analysis and interpretation is that there are restricted viewpoints of the game. 3D reconstruction allows us to have virtual replay from any viewpoint so that the events such as penalties can be detected easily. For achieving this purpose, we use many cameras with overlapped views that cover almost all parts of the field. After some preprocessing, 3D reconstruction and texture mapping, we can enhance the viewer experience by having arbitrary viewpoint of the match. In this research, we use two different visual hull methods for 3D reconstruction. In the first method, the visual hull of an object is computed efficiently and robustly from image contours. This... 

Object recognition is a field of image processing with the purpose of object detection and determining its pose. There was a wide research of object recognition using 2d information. These methods are less efficient due to their sensitivity to view and scale. Today with development of 3d technology, 3d reconstruction of objects has been eased, thus there is a new trend of 3d methods. 3d object recognition uses 3d data and model to recognize objects more efficiently in different views and in occlusion and clutter. The related works are classified in three category of view-based, feature matching, and classification. In this research we attempted to improve one of the best feature matching... 

Today, advances in technology caused the emergence of a need for intelligent systems which can operate without human supervision, and have variety of applications in security, industry, transportation and sport events. Most of these systems require faster and more accurate object tracking. Lots of surveillance and computer vision applications need a process to detect and track objects. For example, the exact location of objects or people is part of the input for applications like movement analysis, counting the number of items, and recognition of people’s behavior. Occlusion is one of the major obstacles in performance of auto-tracking systems. There are several methods to address this... 

During past decade, human pose estimation has become a very important topic in computer vision with many applications; such as robotic, human computer interaction, and analyzing sport videos. Pose estimation is the process of estimating the configuration of the body joints from one or more images. Pose estimation in 2D space has been performed by processing of the images of a single camera. Recently, the multi-view methods have been emerged to estimate 3D human pose.The purpose of this thesis is 3D human pose estimation from multi-view images, captured in football matches. Pictorial structure is an efficient method in 2D human pose estimation. The 3D extension of this method is studied in... 

Simultaneous localization and mapping (SLAM) is the action of detecting robot pose in an unknown environment and building the environment map by use of input data that captured from robot sensors. In visual SLAM, the input data for the robot, is limited to camera sensors. Nowadays, SLAM is one of the main challenges in robotic research.For autonomous action, we need robot pose in the map of the environment. The map production in the indoor environment, there is no GPS data, is one of the research issue in robotic community, in last decade. In this thesis, a new and efficient method is proposed for SLAM at the level of objects. The maps produced by state of the art methods don’t have a...