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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Applying Morphological Filter to Stereo Video Compression

Chen, Chi-Hung 05 September 2005 (has links)
The topic of stereo video is getting more attention among these days due to its high quality of visual effect. However, the large volume of data is the problem of its application. There is much similarity between the parallax videos. This similarity is obtained by a shape compensation technique. The topic of this thesis is to investigate a compression technique by on the shape compensation stereo video data. The shape transformation in this paper is coded by the kinds of morphological operations to be applied. This processing is a type of operation by which the spatial form or structure of objects within an image are modified. Morphological operation is usually applied to the binary images. There are two problems for the selection of the optimal morphological filter: the collection of the candidate filters and the sources of the voters. For the gray level images the mask operation is changed to be the more complex window weighting operation. By a strategy of slicing the image umbrella, our masked gray morphological operation is also more computation-efficient than the regular gray morphological operation. Experimental results in this thesis have demonstrated that shape compensation is more efficient than motion compensation for the secondary (right) video sequence.
42

Framtidens Ljudsystem : Utveckling av ett trådlöst och akustiskt unikt högtalarsystem med interaktivt styrcenter

Strandgren, Victor, Johansson, Fredrik January 2009 (has links)
<p>Den här rapporten redovisar arbetet bakom en utveckling och framtagning av aktiva, trådlösa hifi-högtalare, där teorier om unika akustiska fenomen testas och bekräftas.  Högtalarna är tänkta att användas som utställningsobjekt och designkoncept. Även ett tillhörande styrsystem har utvecklats.</p><p>Arbetet inleddes med en omfattande förstudie som innefattade användarundersökning och konkurrensstudie. Utifrån dessa kunde en kravspecifikation utformas som skulle komma att fungera som ett styrdokument genom designprocessen.</p><p>Idégenereringsmetoder, konceptval, modellering samt fysisk byggnation ledde fram till gruppens önskade resultat. Stor tyngd lades även på att hålla ett genomgående formspråk i alla delar av systemet, där vi fokuserade på att utgå ifrån de former som är av stor akustisk betydelse, så att ljudegenskaperna kunde optimeras, samtidigt som en god design kunde erhållas.</p><p>Resultatet blev två stycken fysiska, fullt funktionella och formmässigt korrekta hifi-högtalare, gjorda åt uppdragsgivaren Transient Design. Det blev även en hel högtalarserie med fronthögtalare i två storlekar, stativhögtalare samt ett tillhörande interaktivt styrsystem. Det unika med detta system är dels kombinationen av trådlösa fullregisterhögtalare som sätter hifi-ljudet i centrum och samtidigt interagerar med en styrenhet som kommunicerar med de ljudkällor som önskas, och dels den hornprincip som högtalarna är byggda efter som ger dem en unik karaktär.</p><p>I slutet av rapporten återfinns en diskussion där projektgruppen reflekterar mer om arbetsgången och resultatet.</p><p> </p> / <p>This report shows the development and production of active, wireless hifi-speakers, where theories about some unique acoustic phenomena are tested and confirmed. The speakers are intended to be used as exhibits and design concepts. Also, an associated control system was developed.</p><p> </p><p>The work began with a comprehensive pilot study that included user survey and a competitor study. The pilot study resulted in a requirement specification which worked as a steering document through the design process. An important part through the project was also to use an consistently design in all of the parts in the system, and the design was built by shapes which gave positive results for the acoustics. This meant that the sound capacity could be optimized and mixed with an attractive design.</p><p> </p><p>The result was two, fully functional hi-fi speakers, made for the client Transient Design as a design concept. It also became a finished speaker series with the front speakers in two sizes, tripod speakers, and an interactive control system. The unique part of this system is partly the combination of the wireless full registry speakers, which puts the hifi-sound in the centre and interacts with head unit, and partly the horn which the speakers have its base design from. The principals of this horn give the speakers a unique character</p><p> </p><p>A discussion in which the project team reflects more about the workflow and the result is found at the end of the report.</p>
43

Stereo vision based obstacle avoidance in indoor environments

Chiu, Tekkie Tak-Kei, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2009 (has links)
This thesis presents an indoor obstacle avoidance system for car-like mobile robot. The system consists of stereo vision, map building, and path planning. Stereo vision is performed on stereo images to create a geometric map of the environment. A fast sparse stereo approach is employed. For different areas of the image there are different optimal values of disparity range. A multi-pass method to combine results at different disparity range is proposed. To reduce computational complexity the matching is limited to areas that are likely to generate useful data. The stereo vision system outputs a more complete disparity map. Abstract Map building involves converting the disparity map into map coordinates using triangulation and generating a list of obstacles. Occupancy grids are built to aid a hierarchical collision detection. The fast collision detection method is used by the path planner. Abstract A steering set path planner calculates a path that can be directly used by a car-like mobile robot. An adaptive approach using occupancy grid information is proposed to improve efficiency. Using a non-fixed steering set the path planner spends less computation time in areas away from obstacles. The path planner populates a discrete tree to generate a smooth path. Two tree population methods were trialled to execute the path planner. The methods are implemented and experimented on a real car-like mobile robot.
44

Stereo imaging and obstacle detection methods for vehicle guidance

Zhao, Jun, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2008 (has links)
With modern day computer power, developing intelligent vehicles is fast becoming a reality. An Intelligent Vehicle is a vehicle equipped with sensors and computing that allow it to perceive the world around it, and to decide on appropriate action. Vision cameras are a good choice to sense the environment. One key task of the camera in an intelligent vehicle is to detect and localise the obstacles, which is the preparation of path planning. Stereo vision based obstacle detection is used in this research. It does not analyse semantic meaning of image features, but directly measures the 3-D coordinates of image pixels, and thus is suitable for obstacle detection in an unknown environment. In this research, a novel correlation based stereo vision method is developed which greatly improves its accuracy while maintaining its real-time performance. Since a vision system provides a large amount of data, extracting refined information may sometimes be complex. In obstacle detection tasks, the purpose is to distinguish the obstacle pixels from the ground pixels in the disparity image. V-Disparity image approach is used in this research to detect the ground plane, however this approach relies heavily on sufficient road features. In this research, a correlation method to locate the ground plane in the disparity image, even without significant road features, is developed. Moreover, traditional V-Disparity images have difficulties detecting non-flat ground, thus having limited applications. This research also develops a method to detect non-flat ground using V-Disparity images, thus greatly widening its application.
45

Stereo Matching Based on Edge-Aware T-MST

Zhou, Dan January 2016 (has links)
Dense stereo matching is one of the most extensively investigated topics in computer vision, since it plays an important role in many applications such as 3D scene reconstruction. In this thesis, a novel dense stereo matching method is proposed based on edge-aware truncated minimum spanning tree (T-MST). Instead of employing non-local cost aggregation on traditional MST which is only generated from color differences of neighbouring pixels, a new tree structure, "Edge-Aware T-MST", is proposed to aggregate the cost according to the image texture. Specifically, cost aggregations are strongly enforced in large planar textureless regions due to the truncated edge weights. Meanwhile, the "edge fatten" effect is suppressed by employing a novel hybrid edge-prior which combines edge-prior and superpixel-prior to locate the potential disparity edges. Then a widely used Winner-Takes-All (WTA) strategy is performed to establish initial disparity map. An adaptive non-local refinement is also performed based on the stability of initial disparity estimation. Given the stereo images from Middlebury benchmark, we estimate the disparity maps by using our proposed method and other five state-of-the-art tree-based non-local matching methods. The experimental results show that the proposed method successfully produced reliable disparity values within large planar textureless regions and around object disparity boundaries. Performance comparisons demonstrate that our proposed non-local stereo matching method based on edge-aware T-MST outperforms current non-local tree-based state-of-the-art stereo matching methods in most cases, especially in large textureless planar regions and around disparity bounaries.
46

Chroma Keying Based on Stereo Images

Chu, Mengdie January 2017 (has links)
This thesis proposes a novel chroma keying method based on stereo images, which can be applied to post-process the alpha matte generated by any existing matting approach. Given a pair of stereo images, a new matting Laplacian matrix is constructed based on the affinities between matching pixels and their neighbors from two frames. Based on the new matting Laplacian matrix, a new cost function is also formulated to estimate alpha values of the reference image through the propagation between stereo images.
47

Intelligent Stereo Video Monitoring System for Paramedic Helmet

Liu, Yang January 2017 (has links)
During the first aid process, when patients are threatened by poor medical conditions, ambulance paramedics are required to administer emergency treatment based on instruc- tions provided by a remote emergency doctor through voice communication. However, such voice communication is always limited in expressing abundant detailed information for the patient. This thesis presents a framework for a stereoscopic and intelligent telemedicine sys- tem that can provide 3D live video communication between paramedics and emergency doctors. The proposed system captures 3D video from the paramedic headset carried by the paramedics, transmits the video through wireless live streaming, and displays the video with a 3D effect for emergency doctors in the hospital. The video can be analyzed to extract information about the patient through embedded algorithm such as face de- tection algorithm. In this thesis, the hardware, functional mechanism and face detection algorithm are introduced separately. The hardware of the system consists of a paramedic headset, a server box and a 3D PC, which are used to capture 3D video, transmit video through live streaming and display video with a stereo effect, respectively. The functional mechanism includes two subsystems, which work for pushing the stereo video to multiple live streams and displaying the 3D video from the live stream. In order to detect the patient information from the video, a multi-task face detection algorithm is applied to analyze the stereo video using deep learning technology. We improved the neural networks of face detection by utilizing 1 ⇥ 1 convolutional layers and retrain the network based on the transfer learning to achieve better and faster performance. This system has achieved good and stable performance in network delay (0.0489ms) and objective video quality evaluations. The face detection algorithm has achieved no- table accuracy (91.78% In FDDB dataset) and efficiency (19.71 ms/frame).
48

Evaluation of the Wi-Fi technique for use in a navigated orthopedic surgery / Evaluation of the Wi-Fi technique for use in a navigated orthopedic surgery

Truhlář, Jindřich January 2012 (has links)
Following text focuses on use of wireless technologies in OrthoPilot navigation system developed by B.Braun company. Description of OrthoPilot software is followed by overview of available wireless technologies highlighting their both advantages and disadvantages. Practical part consists of two main parts, mostly dealing with electronic circuits. First part describes development process of camera-wireless printed circuit board which substitutes currently used RS-422 cable connection between PC and stereo camera. Part of this chapter covers programming in C++ in order to make interface compatible with the rest of current OrthoPilot software. Second bigger part deals with remote controller development using prototyping board mikroMedia for XMEGA. Besides electrical circuits design, chapter describes also software part - microcontroller programming in C language. Thesis is concluded by discussing system limitations and ideas for future development.
49

Aplikace stereovize a počítačového vidění / Computer vision and stereo vision

Bubák, Martin January 2014 (has links)
This dissertation work is describing the usage of the software tool Computer Vision System Toolbox to create applications in computer vision. At the beginning of the work is performed background research of image scanning and its representation by using colour models. It is followed by a description of epipolar geometry and lastly is stated a description of the Computer Vision System Toolbox. In the next section of the work we deal with setting of used Basler cameras and processing of the scanned image. The following is a description how to create applications for object detection and after this description, we get to know applications for creation of depth maps area.
50

Cooperative Shape from Shading and Stereo for 3D Reconstruction

Fortuna, Jeff 04 1900 (has links)
This thesis presents a survey of techniques to obtain the depth component from two­-dimensional (2D) images. Two common techniques - stereo and shape from shading are examined here. Their performance is compared with an emphasis on noting the fundamental limitations of each technique. An argument is presented which suggests an adjustment of the paradigm with which stereo and shape from shading have been treated in three-dimensional vision. The theoretical development of the stereo and lighting models is followed by experiments illustrating use of these models for a variety of objects in a scene. A comparison of the results provides a motivation for combining them in a particular way. This combination is developed, and its application is examined. Using the model that is consistent for both shape and lighting, significant improvement over either stereo or lighting models alone is shown. / Thesis / Master of Engineering (ME)

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