Enhancement of JPEG-Compressed Images by Re-application of JPEG
Journal of VLSI Signal Processing Systems - Special issue on multimedia signal processing
Deringing cartoons by image analogies
ACM Transactions on Graphics (TOG)
Reduction of blocking artifacts in JPEG compressed images
Digital Signal Processing
Combined frequency and spatial domain algorithm for the removal of blocking artifacts
EURASIP Journal on Applied Signal Processing
Pre- and post-shift filtering for blocking removing in downsizing transcoding
IEEE Transactions on Circuits and Systems for Video Technology
Digital image source coder forensics via intrinsic fingerprints
IEEE Transactions on Information Forensics and Security
Objective perceptual video quality measurement method based on hybrid no reference framework
ICIP'09 Proceedings of the 16th IEEE international conference on Image processing
JPEG error analysis and its applications to digital image forensics
IEEE Transactions on Information Forensics and Security
ICCOM'06 Proceedings of the 10th WSEAS international conference on Communications
Reduction of blocking artifacts in block-based compressed images
ACIVS'05 Proceedings of the 7th international conference on Advanced Concepts for Intelligent Vision Systems
Blocking artifacts measurement based on the human visual system
ICNC'05 Proceedings of the First international conference on Advances in Natural Computation - Volume Part I
A training-based method for reducing ringing artifact in BDCT-encoded images
EGMM'04 Proceedings of the Seventh Eurographics conference on Multimedia
Non-causal temporal prior for video deblocking
ECCV'12 Proceedings of the 12th European conference on Computer Vision - Volume Part V
Adaptive non-local means filter for image deblocking
Image Communication
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One drawback of the discrete cosine transform (DCT) is visible block boundaries due to coarse quantization of the coefficients. Most restoration techniques for the removing blocking effect are variations of low-pass filtering, and as such, result in unnecessary blurring. The authors propose a new approach for reducing the blocking effect which can be applied to conventional transform coding without introducing additional information or significant blurring. The method exploits the correlation between the intensity values of boundary pixels of two neighboring blocks. It is based on the theoretical and empirical observation that under mild assumptions, quantization of the DCT coefficients of two neighboring blocks increases the expected value of the mean squared difference of slope (MSDS) between the slope across two adjacent blocks, and the average between the boundary slopes of each of the two blocks. The amount of this increase is dependent upon the width of quantization intervals of the transform coefficients. Therefore, among all permissible inverse quantized coefficients, the set which reduces the expected value of this MSDS by an appropriate amount is most likely to decrease the blocking effect. To estimate the set of unquantized coefficients, the authors solve a constrained quadratic programming problem. The approach is based on the gradient projection method. It is shown that from a subjective viewpoint, the blocking effect is less noticeable in the author' processed images than in the ones using existing filtering techniques