JPEG 2000: Image Compression Fundamentals, Standards and Practice
JPEG 2000: Image Compression Fundamentals, Standards and Practice
Fast multiplierless approximations of the DCT with the liftingscheme
IEEE Transactions on Signal Processing
Curved wavelet transform for image coding
IEEE Transactions on Image Processing
Adaptive Directional Lifting-Based Wavelet Transform for Image Coding
IEEE Transactions on Image Processing
Direction-Adaptive Discrete Wavelet Transform for Image Compression
IEEE Transactions on Image Processing
Space-Frequency Quantization for Image Compression With Directionlets
IEEE Transactions on Image Processing
Shape-adaptive DCT with block-based DC separation and ΔDC correction
IEEE Transactions on Circuits and Systems for Video Technology
Overview of the H.264/AVC video coding standard
IEEE Transactions on Circuits and Systems for Video Technology
Variable block-size transforms for H.264/AVC
IEEE Transactions on Circuits and Systems for Video Technology
IEEE Transactions on Circuits and Systems for Video Technology
Context-based adaptive binary arithmetic coding in the H.264/AVC video compression standard
IEEE Transactions on Circuits and Systems for Video Technology
Rate-constrained coder control and comparison of video coding standards
IEEE Transactions on Circuits and Systems for Video Technology
Lifting-Based Directional DCT-Like Transform for Image Coding
IEEE Transactions on Circuits and Systems for Video Technology
Directional Discrete Cosine Transforms—A New Framework for Image Coding
IEEE Transactions on Circuits and Systems for Video Technology
Journal of Visual Communication and Image Representation
Journal of Visual Communication and Image Representation
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The direction-adaptive partitioned block transform (DA-PBT) is proposed to exploit the directional features in color images to improve coding performance. Depending on the directionality in an image block, the transform either selects one of the eight directional modes or falls back to the nondirectional mode equivalent to the conventional 2-D DCT. The selection of a directional mode determines the transform direction that provides directional basis functions, the block partitioning that spatially confines the high-frequency energy, the scanning order that arranges the transform coefficients into a 1-D sequence for efficient entropy coding, and the quantization matrix optimized for visual quality. The DA-PBT can be incorporated into image coding using a rate-distortion optimized framework for direction selection, and can therefore be viewed as a generalization of variable blocksize transforms with the inclusion of directional transforms and nonrectangular partitions. As a block transform, it can naturally be combined with block-based intra or inter prediction to exploit the directionality remaining in the residual. Experimental results show that the proposed DA-PBT outperforms the 2-D DCT by more than 2 dB for test images with directional features. It also greatly reduces the ringing and checkerboard artifacts typically observed around directional features in images. The DA-PBT also consistently outperforms a previously proposed directional DCT. When combined with directional prediction, gains are less than additive, as similar signal properties are exploited by the prediction and the transform. For hybrid video coding, significant gains are shown for intra coding, but not for encoding the residual after accurate motion-compensated prediction.