Integer DCT Based on Direct-Lifting of DCT-IDCT for Lossless-to-Lossy Image Coding

Abstract

A discrete cosine transform (DCT) can be easily implemented in software and hardware for the JPEG and MPEG formats. However, even though some integer DCTs (IntDCTs) for lossless-to-lossy image coding have been proposed, such transform requires redesigned devices. This paper proposes a hardware-friendly IntDCT that can be applied to both lossless and lossy coding. Our IntDCT is implemented by direct-lifting of DCT and inverse DCT (IDCT). Consequently, any existing DCT device can be directly applied to every lifting block. Although our method requires a small side information block (SIB), it is validated by its application to lossless-to-lossy image coding.

Integer fast lapped transforms based on direct-lifting of DCTs for lossy-to-lossless image coding

“…As a result, although the proposed IntFLTs are apparently sacrificing the complexity to achieve the lossless mode compared with LiftLT, they have a great potential for fast implementation which is dependent on the architecture design and DCT algorithms. Furthermore, the proposed IntFLTs do not need any side information unlike IntDCT based on directlifting as our previous work [35]. Moreover, they can be easily extended to larger size which is recently required as in DCT for H.26x series.…”

“…In [35], we have presented direct-lifting which is a class of block-lifting [25] known as a more effective lifting structure for lossy-to-lossless image coding than standard lifting structure [17][18][19]. The block-lifting reduces rounding error by merging many rounding operations.…”

“…The HLT is composed of lifting structures [17][18][19] with rounding operations and achieves integer-to-integer http://jivp.eurasipjournals.com/content/2013/1/65 transform, whereas it does not have enough coding performance, especially for images with many high frequency components. Various lifting-based filter banks (L-FBs) [20][21][22][23][24][25][26][27][28], which contain integer DCTs (IntDCTs) [29][30][31][32][33][34][35], have been researched to improve coding performance. However, these except for IntDCTs are not practical due to the complexity.…”

Extended Block-Lifting-Based Lapped Transforms

“…The block-lifting structure reduces such rounding errors by merging many rounding operations. A special class of block-lifting structure is expressed as [13] (3) wherein each matrix is defined as Actually, the block-lifting matrices on both sides of the delay matrix are collectively implemented, as shown in Fig. 2.…”

Notice of Violation of IEEE Publication Principles - A DCT approximation with low complexity for image compression

“…Each image was divided into8X8 sub blocks then submitted to 2D approximate transforms implied by the proposed matrix. An 8X8 image block is subjected to the approximation mathematically [10] where it is a considered transformation. This computation furnished 64 approximate transform domain coefficients for each sub block.…”