Enhancement of JPEG-Compressed Images by Re-application of JPEG
Journal of VLSI Signal Processing Systems - Special issue on multimedia signal processing
Block effect reduction by the 1-D gray polynomial interpolation
Digital Signal Processing
Learning-based image restoration for compressed images
Image Communication
MPEG postprocessing system using edge signal variable filter
ICIAR'06 Proceedings of the Third international conference on Image Analysis and Recognition - Volume Part I
Application of feedforward neural network for the deblocking of low bit rate coded images
AIS'04 Proceedings of the 13th international conference on AI, Simulation, and Planning in High Autonomy Systems
Hybrid deblocking algorithm for block-based low bit rate coded images
PCM'05 Proceedings of the 6th Pacific-Rim conference on Advances in Multimedia Information Processing - Volume Part I
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We propose a simple yet efficient method which reduces the blocking artifact in block-coded images by using a wavelet transform. An image is considered as a set of one-dimensional signals, and so all processing including the wavelet transform are one-dimensionally executed. The artifact reduction operation is applied to only the neighborhood of each block boundary in the wavelet transform at the first and second scales. The key idea behind the method is to remove the blocking component which reveals stepwise discontinuities at block boundaries. Each block boundary is classified into one of shade region, smooth edge region, and step edge region. Threshold values for the classification are selected adaptively according to each coded image. The performance is evaluated for 512×512 images JPEG coded with 30:1 and 40:1 compression ratios. Experimental results show that the proposed method yields not only a PSNR improvement of about 0.69-1.06 dB, but also a subjective quality nearly free of the blocking artifact and edge blur