Papers by Bibhas Chandra Dhara
Block truncation coding (BTC) divides an image into blocks having given size and then encodes eac... more Block truncation coding (BTC) divides an image into blocks having given size and then encodes each block by two representative gray levels and a bit-pattern. In this work a modified scheme of BTC is proposed where the computed representative gray levels are the bias and the contrast in each block. Secondly, instead of determining bit-pattern for each block, an optimum bit-pattern is selected from a pattern-book. Thus the index of the optimum pattern is used to encode in lieu of the explicit pattern.
Abstract Motion estimation is important for compression of video sequences. In this paper a new b... more Abstract Motion estimation is important for compression of video sequences. In this paper a new block motion estimation algorithm proposed. In the proposed method, the motion vector of previous frame are used to predict the initial motion vector and the search direction. The extent of search region is determined by predicted motion vector and motion vectors of four casual neighbours in the current frame. Results shows significant speed-up compared to existing ones.
Abstract In this paper we have proposed a novel face recognition method. This method is a hybrid ... more Abstract In this paper we have proposed a novel face recognition method. This method is a hybrid of holistic and structural approaches. First, we locate the position of the nose tip and then we divide the image into eight octants with nose tip as the center. The petal projection method is employed on each octant to obtain a radial intensity profile. Then these radial intensity profiles are transformed by DCT for more compact and scale free representation.
This paper describes a color image compression technique based on block truncation coding using p... more This paper describes a color image compression technique based on block truncation coding using pattern fitting (BTC-PF). High degree of correlation between the RGB planes of a color image is reduced by transforming them to O1O2O3 planes. Each Oi plane (1⩽ i⩽ 3) is then encoded using BTC-PF method. Size of the pattern book and the block size are selected based on the information content of the corresponding plane.
Abstract In the present era of multimedia, the requirement of image/video storage and transmissio... more Abstract In the present era of multimedia, the requirement of image/video storage and transmission for video conferencing, image and video retrieval, video playback, etc. are increasing exponentially. As a result, the need for better compression technology is always in demand. The limited bandwidth of internet also asks for transmission of desired objects only. Progressive image transmission provides such facilities, where transmission is done in steps and the transmission of undesired image can be stopped at an early stage.
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Papers by Bibhas Chandra Dhara