Rate and Quality Control with Embedded Coding and Moving Object Detection of Mobile Cameras
| Autor: | Chien-Ting Kuo, 郭建廷 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Because mobile robots are active and spontaneous, the studies on mobile robots have been more popular in recent years. Especially in the applications of surveillance system, the cooperation among security mobile robots can help finish task more efficiently. Thus, real-time video transmission and information communication become very important. However, there is no quality of service (QoS) guarantee for video transmission over the current Internet. Transmission over heterogeneous network usually causes congestion which leads to high packet loss ratio and delay and degrades the presentation quality of received video. Rate control has been proposed by past studies to prevent congestion occurs. Different types of rate control mechanisms coding and delivery in different methods to compromise the tradeoff between bandwidth efficiency and flexibility. The thesis proposes a receiver-based, rate and quality control. The main principle is to regulate encoding rate to guarantee the video quality is acceptable, especially in region of interest. Transmitting the encoded bit stream in multicast delivery not only improves bandwidth efficiency but also provides different quality for receivers with different length of bit stream. The overall mechanism can be separated into spatial and temporal sampling. Temporal sampling chooses the clearest frame to reduce the cost of encoding and transmitting blur or similar frame. On the spatial sampling, a method to detect moving object by eliminating the changing backgrounds caused by the motion of mobile camera is proposed. Then, embedded coding is performed to discard partial wavelet coefficients to provide multi-resolution of the frame. Encoding the region where there is moving objects in prior to the fixed background guarantees the quality in region of interest is acceptable. The thesis simulates in three scenarios. The objectives are to the correctness of moving object detection in mobile cameras, to analyze the quality of received video under different bandwidth limitation, and to examine the bandwidth efficiency with the proposed rate and quality control. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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