http://hdl.handle.net/10397/201 Search the Channel search http://repository.lib.polyu.edu.hk/jspui/simple-search http://hdl.handle.net/10397/1930 Title: A block motion vector estimation using pattern based pixel decimation<br/><br/>Authors: Chan, Yui-lam; Hui, Wai-lam; Siu, Wan-chi<br/><br/>Abstract: A new pixel decimation technique based on a set of the pixel patterns for block motion vector estimation is presented. For uniform pixel decimation, regular patterns are used for computing the matching criterion to estimate the motion vector. The results can easily be misled by some image textures. Thus, in this paper, we define some “most representative pixel patterns” and make the selection according to the image content in each block for the matching criterion. Our approach can efficiently compensate the drawback in uniform pixel decimation. Computer simulations show that this technique is close to the performance of the full search, and has a significant reduction on computational complexity as compared with other pixel decimation algorithms in the literature. Also, it is more convenient for hardware realization as compared with the fully adaptive pixel decimation.<br/><br/>Description: DOI: 10.1109/ISCAS.1997.622014 Wed, 01 Jan 1997 00:00:00 GMT http://hdl.handle.net/10397/1929 Title: Block motion vector estimation using edge matching : an approach with better frame quality as compared to full search algorithm<br/><br/>Authors: Chan, Yui-lam; Siu, Wan-chi<br/><br/>Abstract: Intensity based block motion estimation algorithms are widely used for exploiting temporal redundancies in video coding. However, blocks located on boundaries of moving objects are not estimated accurately, which are very sensitive to the human eyes. In this paper, we propose a novel approach which incorporates edge matching techniques to accurately predict the motion of moving objects such that the motion compensated frames are tied more closely to the physical features. Besides, accurate motion vectors of edge blocks can be used to develop an efficient block motion estimation algorithm. Experimental results show that our approach requires simple computational complexity, and it gives a significant improvement in accuracy on motion compensated frames as compared with the traditional intensity based methods, including the full search algorithm.<br/><br/>Description: DOI: 10.1109/ISCAS.1997.621968 Wed, 01 Jan 1997 00:00:00 GMT http://hdl.handle.net/10397/1926 Title: Efficient interframe transform coding using temporal context<br/><br/>Authors: Chan, Yui-lam; Siu, Wan-chi<br/><br/>Abstract: Three dimensional (3D) transform coding can reduce the interframe redundancy among a number of consecutive frames, while the motion compensation technique can only reduce the redundancy of at most two frames. The former is very efficient when the correlation between interframe pixels is high. However, the performance will be degraded for complex scenes with a large amount of motions. This paper presents a three dimensional discrete cosine transform (3D-DCT) coding with variable temporal lengths, which is based on the local temporal activity. Two scene change detectors are used to detect the local temporal activity. Our idea is to let the motion activity in each block (with variable temporal length) be very low, while the efficiency of the 3D-DCT coding is increased. Through intensive computer simulations, the performance of the proposed 3D-DCT coding has been found to have substantial improvement over the conventional fixed length 3D-DCT coding. Furthermore, it is significant to point out that the performance of our proposed algorithm is better than that of the MPEG coding.<br/><br/>Description: DOI: 10.1109/ISCAS.1996.541843 Mon, 01 Jan 1996 00:00:00 GMT http://hdl.handle.net/10397/1925 Title: A new block motion vector estimation using adaptive pixel decimation<br/><br/>Authors: Chan, Yui-lam; Siu, Wan-chi<br/><br/>Abstract: A new adaptive technique based on pixel decimation for estimating motion vector is presented. In traditional approach, a uniform pixel decimation is used. Since some pixels in each block do not enter into the matching criterion, this approach might limit the accuracy of the motion vector. We select the most representative pixels based on image content in each block for the matching criterion. This is due to the fact that high activity in the luminance signal such as edges and texture contributes mainly to the matching criterion. Our approach can compensate the drawback in standard pixel decimation techniques. Computer simulations show that this technique is close to the performance of the exhaustive search with a significant reduction on computational complexity.<br/><br/>Description: DOI: 10.1109/ICASSP.1995.479940 Sun, 01 Jan 1995 00:00:00 GMT