Loading...
Search for:
color
0.012 seconds
Total 276 records
Face Detection in Color Images
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
Human face detection is an important research area with several applications such as human computer interface (HCI), face recognition, surveillance systems, security systems, and content-based image retrieval (CBIR). Face detection problem can be stated as “determining whether there are human faces in the image” and if there are “returning the location of each human face in the image” regardless of its position, size, scale, orientation, and lighting condition. In this thesis, we have proposed a new face detection method which combines the AdaBoost algorithm with skin color information and support vector machine (SVM). First, a cascade classifier based on AdaBoost is used to detect faces in...
Using Visual Patterns for Precise Automatic Landing of a Quadcopter
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor)
Abstract
In this study, the method of recognizing image patterns by image processing to guide the quadcopter to the landing point is expressed. For this, first the forces and torques on the quadcopter in the body system are calculated and after transferring to the inertial coordinates, the quadcopter dynamics with the use of Newton-Euler law is simulated in the MATLAB software environment. Then, a simple PID controller is designed to control the attitude, height and position of the quadcopter and create stability in the quadcopter dynamics. Because quadcopter navigation is dependent on visual data, a simulation environment called VRML is used. This environment has the ability to create a...
Actor-based Timing Analysis in Automotive Systems
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor)
Abstract
Meeting timing constraints is crucial for the correct behavior of embedded systems in modern vehicles. In the automotive domain, TADL2 Timing constraints are widely used and accepted standards for repetitive and critical timing requirements. However, ensuring these constraints in modern automotive systems, which encompass over 150 Electronic Control Units (ECUs), is challenging due to the increased complexity of automotive systems. Previous work proposed formal frameworks for specifying and verifying timing constraints, mostly based on timed automata, Time(d) Petri Nets, and TCTL logic for specification, which are the most prominent formalisms in the timed system's domain. They used UPPAAL...
Conflict-free Coloring Game
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
Conflict-free coloring problem is one of the computational geometry problems that has been studied in the last two decades. The root of this problem comes from the frequency assignment to cellular networks problem. In that research, we have a cellular network containing several regions in two-dimensional plane and we want to assign a frequency to each of the regions so that if we look at any intersection of them, there is a region with a unique color compared to other regions of that intersection. In other words, a person’s cellular phone in the range of some regions (in the intersection of them) would be able to connect to one antenna with a unique frequency and function properly. This...
K-Strong Conflict Free Coloring of Regions with Respect to a Family of Points
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
The conflict-free coloring is one of the computational geometry problems that has received attention in the last two decades. The root of this problem comes from the frequency allocation problem to telecommunications antennas, where we have several telecommunication antennas in two-dimensional space aiming to assign to each of them a frequency so that every point on the plane, which is at least inside one of the antenna ranges, stays in a range with a frequency different from the other antennas containing point.One of the generalizations of this problem is the k-strong case, where we have n regions (equivalent to the circular region of the antennas) that we want to color so that for each...
Approximation Algorithms for Edge Coloring in the Streaming Model
, M.Sc. Thesis Sharif University of Technology ; Zarrabizadeh, Hamid (Supervisor)
Abstract
The edge coloring problem is one of the most fundamental problems in graph theory. In this problem, the task is to assign colors to edges so that no two incident edges have the same color. Although finding an optimal edge coloring is NP-hard, Vizing’s theorem asserts that ∆+1 colors are always sufficient, denoting the maximum degree in the graph by ∆.Due to significant increase in the volume of data, for most problems, storing the whole data is not possible. This had led to emergence of new models of processing data such as data streaming model. In semi-streaming model the input graph is represented as a stream of edges, and the storage space of an algorithm is bounded by O(n. polylog n). So...
Online Conflict-free Coloring of Regions
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
Let S be a set of n regions of some fixed type (such as discs, axis-parallel rectangles, etc). A conflict-free coloring (CF-coloring) of S is an assignment of colors to each region such that for every point p covered by a non-empty subset of S, there is a region with a unique color among the regions containing p. The goal is to use minimum number of colors. In this thesis we study online CF-coloring for axis-parallel rectangles in the plane which rectangles are on x-axis. We present a randomized algorithm with O(〖log〗^6 n) colors. We also prove that this algorithm works with high probability
Conflict-Free Coloring for Moving Objects
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
Let S be a set of n regions of some fixed type (such as discs, axis-parallel rectangles, etc). A conflict-free coloring (CF-coloring) of S is an assignment of colors to each region such that for every point p covered by a non-empty subset of S, there is a region with a unique color among the regions containing p. We try to maintain a CF-coloring as the objects move. Regions are moving, so after an intersection, the coloring might not be conflict-free anymore and we need to recolor some regions. The goal is to recognize the intersections and to minimize both the total number of colors used and the number of recolorings needed. In this thesis we study kinetic CF-coloring for moving...
Performance Evaluation of Cloud Services Considering Live Virtual Machine Migration
, M.Sc. Thesis Sharif University of Technology ; Movaghar, Ali (Supervisor)
Abstract
The proliferation of cloud services and drastic growing of IaaS data centers,encourage providers to adopt more intelligent approaches to save more energy and as a result, save more money. Today’s novel techniques such as virtualization and live virtual machine migration, provide effective solutions to service providers to fulfill this need. However, investigate the effect of different resource management and virtual machine migration approaches in virtualized data centers, require great efforts. Therefore, in this research work, we propose a model based on Colored Petri Nets to investigate the effect of live virtual machine migration in cloud data centers. Our proposed model is able to...
Conflict-free Chromatic Art Gallery Covering with Vertex Guards
, M.Sc. Thesis Sharif University of Technology ; Ghodsi, Mohammad (Supervisor)
Abstract
The visibility is one of the most important problems in computational geometry. Two points are said to be visible to each other, if the line segment that joins them does not intersect any obstacles. The art gallery problem is a well-studied visibility problem in computational geometry. It originates from a real-world problem of guarding an art gallery with the minimum number of guards who together can observe the whole gallery. In many of applications, the “guards” are “landmarks” deployed in an environment to help provide navigation and localization service to mobile robots. The mobile device communicates with these landmarks through wireless, or other “line-of-sight” signaling...
Computing Fundamental Colored Graph Properties in Sublinear Time
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
Because of growing amount of data which communicated across the world, analyzing massive data set becomes more important than ever. The graph structure as an important and broadly used data structure is much more important than others. In this thesis, besides introducing the sublinear time algorithm model for massive data as a very efficient and superfast method to deal with massive data, we use them to solve problems for colored graphs. As a fundamental property, we try to compute the average of colored degree. This problem is analyzed from different aspects with various limitation. Two algorithms with multiplicative approximation factor, based on the average degree of simple graphs are...
Conflict-free Coloring with Recoloring
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
A coloring of regions is conflict-free if for any covered point in the plane, there exist a region that cover it, with a unique color. In this thesis, we examine the problem of conflict-free coloring of regions in dynamic model, with minimum colors, and with the possibility of recoloring the optimal numbers of colored regions. That means, regions are inserted one by one on the plane, and by inserting any region, inserted regions shall be conflict-free. Dynamic model are divided into three categories: offline model, online with absolute positions model and online with relative positions model. The difference between these three categories is in the information contained in insertion of...
Content Based Image Retrieval Using Segmentation Similarity Measure
,
M.Sc. Thesis
Sharif University of Technology
;
Jamzad, Mansour
(Supervisor)
Abstract
Content Based Image Retrieval (CBIR) is a research area in computer vision. This area comprises of two main steps, low level feature extraction such as color, texture and shape extraction and also similarity measures for comparison of images. The challenge in this system is the existence semantic gap between the low level visual features and the high level image semantics. The aim of research in this field is to reduce this semantic gap. In this study the images are divided into regions using Meanshift method, for color segmentation and then moments of each region as color feature are calculated. Also for extracting texture the images are divided into regions using Jseg method, and then...
Analysis and Verification of a Routing Protocol Conformance Test Program
, M.Sc. Thesis Sharif University of Technology ; Jahangir, Amir Hossein (Supervisor)
Abstract
Routers play a key role in transferring information between various Networks. It is very important to make sure about the compatibility of OSPF in a router with its standard description. In this regard, before presenting or applying a router and also evaluating its performance, it is necessary to carry out conformance test with the help of network equipment testers Tester designers extract test cases from protocol standard description through non-formal ways and exam them on network equipment.
In this thesis, a part of OSFP protocol has been modeled through colored Petri nets. In this regard, two sections of OSPF RFC have been model checked: neighbor state machine and data base...
In this thesis, a part of OSFP protocol has been modeled through colored Petri nets. In this regard, two sections of OSPF RFC have been model checked: neighbor state machine and data base...
Online Conflict-free Coloring Of Intervals
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
In this thesis, we consider the problem of online conflict-free coloring for regions. First, we analyze online variant of the conflict-free coloring of intervals on the line, where each newly inserted interval must be assigned a color upon insertion such that the coloring remains conflict-free, i.e. for every point p in the union of the current intervals, there must be an interval I with a unique color among all intervals covering p. we present deterministic algorithm for achieving this goal which uses O(log^3n) color. Next, we consider the online conflict-free coloring of nearly-equal axis-parallel rectangles in the plane and present a deterministic algorithms which uses O(log^12n)...
Use of Fuzzy Type 2 in Image/Video Retrieval
, M.Sc. Thesis Sharif University of Technology ; Ghanbari, Mohammad (Supervisor)
Abstract
In content based image retrieval, low level features are used to find similar image. To do this, many system has been proposed by other people, in which in many of them, combination of features in the same time are used as a step of retrieval to increase accuracy. Feature combination are divied in two category: vector based and weight based which in weight based approach, features can get different weight, based on their importance and role in retrieval accuracy. Each image contain different partition, which some of them like background, base on their lower discrimintivity power, have lower importance. Based on our study, some image have powerfull color features and some of them have...
Minimum Color-spanning Tree
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
In the general case of minimum color-spanning tree which is one of the color-spanning set problems, given a weighted graph with n vertices of k different colors, the goal is to find a subtree of minimum weight such that vertices of this subtree include all the colors in the graph. In the planar case, the input is a complete graph with n colored vertices on the plane and the weight of each edge is the Euclidean distance between its corresponding vertices. In this thesis we consider the problem of minimum color-spanning tree. To this end, first we present various color-spanning set problems and some other related problems like Steiner tree and we study the previous work on these problems. Then...
A Hybrid Method for Improving the Color Constancy in Images
, M.Sc. Thesis Sharif University of Technology ; Jamzad, Mansour (Supervisor)
Abstract
The ability of measuring colors of objects, independent of light source illumination, is called color constancy which is an important field in machine vision and image processing. In this thesis, we propose five new combinantional ways in color constansy fields. The first two proposed methods use neural networks to combining basic methods. The third and forth proposed methods use fuzzy measures and integrals for combining color constancy methods. And finally fifth method combines methods with indoor outdoor classification this method has the best result (3.01 median angular error) in proposed methods and past methods in color constancy fields. It is shown in this article that the proposed...
Scene Classification Based on Color and Texture Features
, M.Sc. Thesis Sharif University of Technology ; Jamzad, Mansour (Supervisor)
Abstract
Scene classification is one of the most controversial fields in computer vision. It has many applications such as robot navigation and control, content-based image retrieval (CBIR), semantic organization of image databases, depth estimation and multimedia services. In fact the outcome of any classification system depends on the ability of the feature vector defined for the problem, by means of its distinguishing strength. In this research we focus on efficient feature extraction methods. In recent years, methods based on bags of features and special pyramid approach, have shown good performance in scene classification comparison to the others. So we based our proposed method on these ideas....
Real Time Car Model and Color Recognition Using SVM
, M.Sc. Thesis Sharif University of Technology ; Jamzad, Mansour (Supervisor)
Abstract
Recently many works has been focused on Automatic Security Systems. Car type and color recognition systems are needed in vehicle based access control systems in buildings, outdoor sites and even housing estates. Another usage of car type and color recognition is when a certain model of car is being investigated in highways and streets. In this thesis two independent systems are designed; one for car type recognition and another for car color recognition. They both require to know the license plate location, so we proposed a license plate detection system. In the license plate detection system, first the plate candidates are extracted from image by gradient and morphological operations, then...