Yuk-Hee Chan

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This paper presents an adaptive demosaicing algorithm. Missing green samples are first estimated based on the variances of the color differences along different edge directions. The missing red and blue components are then estimated based on the interpolated green plane. This algorithm can effectively preserve the details in texture regions and, at the same(More)
This paper proposes a new approach to reduce coding artifacts in transform image coding. We approach the problem in an estimation of each transform coe cient from the quantized data by using its local mean and variance. The proposed method can reduce much coding artifacts of low bit-rate coded images, and at the same time guarantee that the resulting images(More)
In most digital cameras, Bayer color filter array (CFA) images are captured and demosaicing is generally carried out before compression. Recently, it was found that compression-first schemes outperform the conventional demosaicing-first schemes in terms of output image quality. An efficient prediction-based lossless compression scheme for Bayer CFA images(More)
bstract. Color demosaicing is critical for digital cameras, because t converts a Bayer sensor mosaic output to a full color image, which etermines the output image quality of the camera. In this work, an fficient decision-based demosaicing method is presented. This ethod exploits a new edge-sensing measure called integrated graient (IG) to effectively(More)
This paper presents a low complexity joint color demosaicking and digital zooming algorithm for single-sensor digital cameras. The proposed algorithm directly extracts edge information from raw sensor data for interpolation in both demosaicking and zooming to preserve edge features in its output. This allows the extracted information to be exploited(More)
This note presents two new fast discrete cosine transform computation algorithms: a radix-3 and a radix-6 algorithm. These two Manuscript received November 21, 1991; revised January 4, 1993. The authors are with the Department of Electronic Engineering, Hong IEEE Log Number 921 1527. Kong Polytechnic, Hung Hom, Kowloon, Hong Kong. new algorithms are(More)
This paper studies the restoration of images which are color-quantized with error diffusion. Though there are many reported algorithms proposed for restoring noisy blurred color images and inverse halftoning, restoration of color-quantized images is rarely addressed in the literature especially when the images are color-quantized with halftoning. Direct(More)
In fractal coding technique, an image is encoded by making use of its self-similarity property. The image can be reconstructed with some well-defined contractive mappings based on this property and hence, in theory, the reconstructed image can be of any desirable size by using an initial image of appropriate size during the decoding process. However, in(More)
For any fault of the same severity level, traditional fault discovery and notification tools provide equal weighting from business points of view. To improve the fault correlation from business perspectives, we proposed a framework to automate network and system alerts with respect to its business service impact for proactive notification to IT operations(More)
A fingerprint recognition algorithm based on the wavelet domain features of a fingerprint image is proposed. Critical wavelet coefficients are selected to form a feature vector of the fingerprint. As compared with a recently reported algorithm using a similar approach, the proposed algorithm is superior in terms of both recognition rate and computational(More)