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Titolo:
Adaptive processing with quadratic programming and LPF for reducing blocking artifacts in DCT image coding
Autore:
Fukuda, K; Kawanaka, A;
Indirizzi:
Sophia Univ, Fac Sci & Technol, Tokyo 1028554, Japan Sophia Univ Tokyo Japan 1028554 Fac Sci & Technol, Tokyo 1028554, Japan
Titolo Testata:
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE
fascicolo: 4, volume: 84, anno: 2001,
pagine: 50 - 59
SICI:
1042-0967(2001)84:4<50:APWQPA>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
TRANSFORM;
Keywords:
DCT; blocking artifacts; quadratic programming; adaptive process; image shaping;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Engineering, Computing & Technology
--discip_EC--
Citazioni:
10
Recensione:
Indirizzi per estratti:
Indirizzo: Fukuda, K Sophia Univ, Fac Sci & Technol, Tokyo 1028554, Japan Sophia Univ Tokyo Japan 1028554 Technol, Tokyo 1028554, Japan
Citazione:
K. Fukuda e A. Kawanaka, "Adaptive processing with quadratic programming and LPF for reducing blocking artifacts in DCT image coding", ELEC C JP 3, 84(4), 2001, pp. 50-59

Abstract

In many image coding methods, the discrete cosine transform (DCT) is used. When the compression ratio is increased, blocking artifacts are generated in the reconstructed image due to quantization error. To resolve this problem, a method is proposed to adaptively change the suppression process of distortion depending on the block. In this method, each block is classified into (1) the flat part where the pel values change monotonically by the value of the received DCT coefficient and (2) the dynamic part. In the block inthe flat part, the DCT coefficients are estimated within the quantization width by the quadratic programming method, and the block is regenerated by replacing the received coefficients. The continuity at the block boundary and the boundary pel values after smoothing are used as the objective function. Higher-order DCT coefficients can be estimated successively. In the region where the variation of the pel values is substantial, human visual sensitivity is not sufficient for the distortion. Therefore, the block boundaryis smoothed with a low-pass filter (LPF) in the block in the variable part. This method is used for processing of several images. It is demonstrated that the SNR is better than those in the JPEG reconstruction method, ac coefficient prediction:method, and the LPF method. Overall, a high-quality reconstructed image is obtained with the blocking artifacts are suppressed. (C) 2000 Scripta Technica.

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Documento generato il 26/01/20 alle ore 22:13:29