Title :
Influence of Image Segment Size on Efficiency of SA DCT
Author :
Garstecki, Pawel ; Ski, Ryszard Stasin
Author_Institution :
Inst. of Electron. & Telecommun., Poznan Univ. of Tech.
Abstract :
In the paper influence of segments size on the efficiency of SA DCT is analyzed. Namely, it is shown that typical in image compression 8times8-pixel blocks are usually too small for obtaining the best PSNR values. Optimal block size depends on compression ratio, it grows from 12times12 pixels for low compression (more than 1 bit per pixel) up to 32times32 pixels or natural (non-rectangular) segmentation for less than 0.5 bits per pixel. The explanation is obvious, it is required that for a segment at least its DC component should be computed, while the number of blocks is inversely proportional to their size. The difference is also clearly seen when evaluating images subjectively
Keywords :
data compression; discrete cosine transforms; image coding; image segmentation; SA DCT; image compression; image segment size; Discrete cosine transforms; Image analysis; Image coding; Image databases; Image segmentation; Multimedia databases; PSNR; Paper technology; Shape; Transform coding;
Conference_Titel :
Signal Processing Symposium, 2006. NORSIG 2006. Proceedings of the 7th Nordic
Conference_Location :
Rejkjavik
Print_ISBN :
1-4244-0412-6
Electronic_ISBN :
1-4244-0413-4
DOI :
10.1109/NORSIG.2006.275286
