| With the increasing need of digital video, video transmission over network has received more and more attention, and object-oriented coding and processing has become a research hot spot. The object-based coding is the core content of MPEG-4, which represents the second generation video coding standard. Some object-based processing technologies are used to guarantee efficient encoding, correct decoding and high quality video outputting. In order to obtain high quality video service, the dissertation studied some of the key processing techniques in network video transport application, which include video object segmentation, shape error concealment and spatial resolution transformation, then, they are used in distributed video surveillance system in heterogeneous environment. The main works are as follows:1. Firstly, according to the characteristic of Human Vision System (HVS), an automatic video objects segmentation method based on the Color Consistency of HVS (CCHVS) is presented. CCHVS obtains the frame difference mask based on human perception, this motion detection method is more effective than traditional ones. The proposed algorithm can handle with complex scenes such as fast moving object and multiple objects and so on efficiently because the moving object is separated by comparing the current frame with the reliable background image. Secondly, in order to adapt to the requirement of MPEG-4 object-oriented processing, a Region Segmentation method based on Video Object (RSVO) is proposed. The mean shift process can be performed in the area of video object. RSVO can speed up calculating time and save memory than traditional mean shift method, and is suitable for situation where high speed is needed and memory resource is restricted.2. A modified octree color quantization algorithm (MOCQ) is proposed. It limits the depth of the octree to 4 to save memory. And adopts a bidirectional pruning mechanism of first up-bottom comparing then bottom-up pruning directly to avoid the large numbers of leaves and improve processing speed. An error diffusion method is used to obtain better image quality.3. Based on Cubic B-spline Interpolation (CBI), a spatial shape error concealment method is proposed. Firstly, to avoid the deficiencies of traditional B-spline interpolation methods that computationally expensive and inconvenient to local modification, a matrix form representation for CBI curve is presented. Then, the matrix form representation is used to shape error concealment. Compared with traditional spatial methods based on Bezier interpolation, the one in this paper generating interpolating curve based on the right received boundary points directly and without inserting any additional control points. At the same time, our method can be implemented simply.4. Based on the rotation and translation invariant properties of both Harris interest point detector and local Zernike moments, a Temporal shape error concealment scheme Robust to Rotation and Translation (TRRT) is proposed. Firstly, to improve the shape motion estimation accuracy, not only the binary alpha shape plane of VO, but also the texture data will be used. Then, the interest points are detected by Harris interest point detector, and the best matching pairs of interest points between two objects are computed by comparing the Euclidean distance of local Zernike moments defined on the interest point neighborhood. The global motion parameters are determined and the previous boundary is motion compensated. Finally, the missing boundary pieces are reconstructed based on the most similar part in the motion compensated boundary. TRRT is robust to rotation and translation movements between objects in consecutive time instants.5. A video Object and Region Directed image interpolation method (ORD) is proposed. Firstly, the scientificity of image interpolation based on uniformity of region is analyzed. Then, image is segmented using RSVO method, and which region an interpolated pixel should belong to is decided by an approach combines the method of the nearest neighbor and the statistical mode. The procedure of interpolation formulas design fully shows the uniformity of region. For pixels within a region, linear interpolation methods are used to keep the smoothness of the region. And for transition pixels between different regions, nonlinear interpolation formulas are designed. Bigger weights are assigned to neighboring pixels that have larger contributions to calculate the interpolated point value. In order to meet the requirement of MPEG-4 object-oriented applications, the region directed processes can be implemented in the area of the object of interest only, while faster and simpler linear method is chosen in other areas. This can save resources while guarantee high quality for the region of interest. Experimental results show ORD can obtain images with higher subjective and objective quality than traditional methods for both up-sampling and down-sampling applications. It obtains good results when ORD is used in underwater laser image enlargement.6. A framework for distributed video surveillance in heterogeneous environment is proposed, and the feasibility of it is demonstrated with a prototype implementation. The performance of the system is improved for those key techniques, which include moving object segmentation, transmission error concealment and image interpolation. The main characteristics of the proposed system are as follows: can be configured remotely to track moving object and adjust the camera parameters automatically; can increase new functions or add new monitoring nodes easily; surveillance can be performed wherever there is internet or mobile telephone signal; the system is cheaper and easier to achieve with simple equipments, so it can be widely used in practice; and can be extended to a third generation (3G) system seamlessly.
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