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
Models for patch-based image restoration
Journal on Image and Video Processing - Special issue on patches in vision
A smoothness constraint set based on local statistics of BDCT coefficients for image postprocessing
Image and Vision Computing
Block effect reduction by the 1-D gray polynomial interpolation
Digital Signal Processing
Image deblocking by the dual adaptive FIR wiener filter and overcomplete representation
ICICS'09 Proceedings of the 7th international conference on Information, communications and signal processing
On the method of multicopy video enhancement in transform domain
ICIP'09 Proceedings of the 16th IEEE international conference on Image processing
Image postprocessing by Non-local Kuan's filter
Journal of Visual Communication and Image Representation
Video enhancement from multiple compressed copies in transform domain
Journal on Image and Video Processing - Special issue on emerging methods for color image and video quality enhancement
An efficient post-processing using DCT domain projections onto convex sets
ICIAR'06 Proceedings of the Third international conference on Image Analysis and Recognition - Volume Part I
An efficient adaptive de-blocking algorithm
CIS'05 Proceedings of the 2005 international conference on Computational Intelligence and Security - Volume Part II
Image de-quantizing via enforcing sparseness in overcomplete representations
ACIVS'05 Proceedings of the 7th international conference on Advanced Concepts for Intelligent Vision Systems
Improved POCS-based deblocking technique using wavelet transform in block coded image
PCM'06 Proceedings of the 7th Pacific Rim conference on Advances in Multimedia Information Processing
A training-based method for reducing ringing artifact in BDCT-encoded images
EGMM'04 Proceedings of the Seventh Eurographics conference on Multimedia
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We propose a novel postprocessing technique, based on the theory of projections onto convex sets (POCS), to reduce the blocking artifacts in transform coded images. It is assumed, in our approach, that the original image is highly correlated. Thus, the global frequency characteristics in two adjacent blocks are similar to the local ones in each block. We consider the high-frequency components in the global characteristics of a decoded image, which are not found in the local ones, as the results from the blocking artifact. We employ an N-point discrete cosine transform (DCT) to obtain the local characteristics, and a 2N-point DCT to obtain the global ones, and then derive the relation between the N-point and 2N-point DCT coefficients. A careful comparison of the N-point with the 2N-point DCT coefficients makes it possible to detect the undesired high-frequency components, mainly caused by the blocking artifact. Then, we propose novel convex sets and their projection operators in the DCT domain. The performance of the proposed and conventional techniques are compared on the still images, decoded by JPEG. The results show that, regardless of the content of the input images, the proposed technique yields significantly better performance than the conventional techniques in terms of objective quality, subjective quality, and convergence behavior