This paper develops a methodology for resizing image resolutions in an arbitrary orthogonal block transform domain. To accomplish this, we represent the procedures resizing images in an orthogonal transform domain in ...
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This paper develops a methodology for resizing image resolutions in an arbitrary orthogonal block transform domain. To accomplish this, we represent the procedures resizing images in an orthogonal transform domain in the form of matrix multiplications from which the matrix scaling the image resolutions is produce. The experiments showed that the proposed method produces reliable performance without increasing the computational complexity, compared to conventional methods when applied to various transforms.
In H.264/AVC, the bits used for the Intra_4x4 prediction mode information usually occupy a high percentage in intra coding. Towards this issue, we present an efficient coding method for the Intra_4x4 prediction mode i...
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ISBN:
(纸本)9781424438273
In H.264/AVC, the bits used for the Intra_4x4 prediction mode information usually occupy a high percentage in intra coding. Towards this issue, we present an efficient coding method for the Intra_4x4 prediction mode information. Firstly, a 3-order Markov random field is introduced to model the correlation among neighboring 4x4 blocks at picture level. Secondly, based on the conditional probabilities learned in this model, we build up a context adaptive coding scheme to code the Intra_4x4 prediction mode information. Although the probabilities and the coding scheme are initialized off-line, they can be revised by automatic adjustments. Thus the proposed algorithm is robust to a variety of video sequences. Experimental results demonstrate that the proposed method can obtain a gain up to 0.3 dB in all I-frames coding without involving any serious computational burden.
Existing vertex-based operational rate-distortion (ORD) optimal shape coding algorithms can use a number of different distortion measurement techniques, including the shortest absolute distance (SAD), the distortion b...
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Existing vertex-based operational rate-distortion (ORD) optimal shape coding algorithms can use a number of different distortion measurement techniques, including the shortest absolute distance (SAD), the distortion band (DB), the tolerance band (TB), and the accurate distortion measurement technique for shape coding (ADMSC). From a computational time perspective, an N-point contour requires O(N-2) time for DB and TB for both polygon and B-spline-based encoding, while SAD and ADMSC incur O(N) time for polygonal encoding but O(N-2) for B-spline based encoding, thereby rendering the ORD optimal algorithms computationally inefficient. This letter presents a novel distortion measurement strategy based on chord-length parameterization (DMCLP) of a boundary that incurs order O(N) complexity for both polygon and B-spline-based encoding while preserving a comparable rate-distortion performance to the original ORD optimal shape coding algorithms.
In this paper, we propose a block-based frequency scalable technique for efficient hierarchical coding. The proposed technique divides an image into its multiple resolution versions, based on the spectral properties o...
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In this paper, we propose a block-based frequency scalable technique for efficient hierarchical coding. The proposed technique divides an image into its multiple resolution versions, based on the spectral properties of discrete cosine transform (DCT) kernels. We present that spectral decomposition, downsampling, and DCT operations are performed effectively over input DCT coefficients of one-dimensional (1-D) and two-dimensional (2-D) signals by using the proposed transform matrices. The proposed image coder is observed to reduce the computational complexity and the memory buffer size with a higher peak signal-to-noise ratio (PSNR), when compared with the traditional hierarchical image coder. In addition, the proposed architecture can preserve compatibility easily with the previous DCT-based image coder.
This paper presents the design and implementation of a low power 8 × 8 2-D DCT chip based on a computation-effective algorithm. Computational complexity can be reduced by simplifying the direct 2-D algorithm. Thu...
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This paper presents the design and implementation of a low power 8 × 8 2-D DCT chip based on a computation-effective algorithm. Computational complexity can be reduced by simplifying the direct 2-D algorithm. Thus, the low power consumption is achieved due to complexity reduction. Besides, the parallel distributed-arithmetic (DA) technique is used to realize constant multiplication due to the low-power consideration. Additionally, the 2 V-power supply is practiced in circuit implementation for now and future battery operated applications. By using the TSMC 0.6μm single-poly double-metal technology, 133 mW power consumption at 100 MHz and the 133 MHz maximum operation speed are achieved by critical path simulation.
Multigeneration is the repeated compression-decompression of images. Under a compression scheme like Transform coding, reconstructed images suffer further degradation at each generation, even though there is no manipu...
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ISBN:
(纸本)0819424358
Multigeneration is the repeated compression-decompression of images. Under a compression scheme like Transform coding, reconstructed images suffer further degradation at each generation, even though there is no manipulation of the image data. This paper describes multigeneration characteristics of transform coded images. We also study motion compensated coding in a multigeneration environment. We present five mechanisms that contribute to the continued degradation in multigeneration: Pixel Domain Quantization (PDQ), Pixel Domain Clipping (PDC), Compression Control Parameters Variation (CCPV), Motion Vector Re-estimation (MVR) and Error Propagation due to Motion Compensation (EPMC). For PDQ, we show that it is not the step size of the DCT domain or the pixel domain quantizers that contributes to the saturation of degradation in multigeneration, but instead the ratio between these two quantizers. We observe that PDC mainly affects the DC coefficient. In CCPV and MVR, multigeneration error is reduced when the quantization scaling parameters and/or the motion vectors of the first generation are used for each subsequent generation. For EPMC, multigeneration errors in reference pictures propagate to frames that are predicted from them. Consequently, EPMC only multiplies the effect of other mechanisms.
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