A Novel Shift Block for Reducing Quantization Effects within Four Adjacent DCT Domains

Author

Chen, Yen-Yu ; Chang, Ying-Wen

Author_Institution

Dept. of Inf. Manage., ChungChou Inst. of Technol., Yuanlin

Volume

1

fYear

2008

fDate

27-30 May 2008

Firstpage

344

Lastpage

348

Abstract

Blocking effect is the major drawback in DCT-based (discrete cosine transformation) codecs at low bit-rates. In this paper, a post-processing filter is proposed in DCT frequency domain. The proposed algorithm uses a shift block within four adjacent DCT blocks to reduce computational complexity. By slightly modifying several DCT coefficients in the shift block, the artifacts that result from quantization and dequantization process are alleviated. The simulation results show that both visual perception and objective image quality are improved noticeably.

Keywords

discrete cosine transforms; filtering theory; image coding; quantisation (signal); DCT blocks; DCT coefficients; blocking effect; dequantization process; discrete cosine transformation codecs; post-processing filter; quantization effects reduction; shift block; Discrete cosine transforms; Filters; Frequency; Image coding; Image edge detection; Image quality; Quantization; Signal processing; Signal processing algorithms; Transform coding; DCT; blocking effect; shift block;

fLanguage

English

Publisher

ieee

Conference_Titel

Image and Signal Processing, 2008. CISP '08. Congress on

Conference_Location

Sanya, Hainan

Print_ISBN

978-0-7695-3119-9

Type

conf

DOI

10.1109/CISP.2008.300

Filename

4566176