A Fast 8 × 8 Pruned DCT Algorithm

✍ Scribed by Mohamed El-Sharkawy; Waleed Eshmawy

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 199 KB
• Volume: 6
• Category: Article
• ISSN: 1051-2004
• DOI: 10.1006/dspr.1996.0015

✦ Synopsis

Pruned DCT Algorithm, Digital Signal Processing 6 other important aspect of DCT is its ability to quan- (1996), 145-154. tize the DCT coefficients using visually weighted quantization values.

A new algorithm that computes the 8 1 8 pruned Discrete

The two-dimensional DCT can be computed using Cosine Transform ( DCT) using the vector-radix approach either the conventional row-column or the convenis introduced. The vector-radix approach decomposes the 8 1 8 pruned DCT into four 4 1 4 pruned DCTs. The 4 1 4 tional direct method. The row-column method takes pruned DCT is then decomposed into four one-dimensional the one-dimensional DCT along the rows after along pruned DCTs. The number of points that need to be calcuthe columns. The direct method works directly on lated from each one-dimensional DCT depends on the althe two-dimensional data sets and requires fewer lowed amount of pruning. The proposed algorithm does not multiplications and additions [2]. It was also shown require any bit reversal operations. To illustrate the usein [3] that the main idea of the two-dimensional fulness of the proposed pruned DCT algorithm, we utilize recursive DCT algorithms is that N 1 N DCT can it to compress images using a Joint Photographic Experts be computed from the next lower DCT matrices. Group ( JPEG) algorithm. The proposed 8 1 8 pruned DCT The standard DCT algorithms inherently assume algorithm improves the compression ratio and reduces both that the length of the input and output sequences the complexity and execution time of the modified JPEG algorithm.