Title :
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
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;
Conference_Titel :
Image and Signal Processing, 2008. CISP '08. Congress on
Conference_Location :
Sanya, Hainan
Print_ISBN :
978-0-7695-3119-9
DOI :
10.1109/CISP.2008.300