132 research outputs found
Aggressive saliency-aware point cloud compression
The increasing demand for accurate representations of 3D scenes, combined
with immersive technologies has led point clouds to extensive popularity.
However, quality point clouds require a large amount of data and therefore the
need for compression methods is imperative. In this paper, we present a novel,
geometry-based, end-to-end compression scheme, that combines information on the
geometrical features of the point cloud and the user's position, achieving
remarkable results for aggressive compression schemes demanding very small bit
rates. After separating visible and non-visible points, four saliency maps are
calculated, utilizing the point cloud's geometry and distance from the user,
the visibility information, and the user's focus point. A combination of these
maps results in a final saliency map, indicating the overall significance of
each point and therefore quantizing different regions with a different number
of bits during the encoding process. The decoder reconstructs the point cloud
making use of delta coordinates and solving a sparse linear system. Evaluation
studies and comparisons with the geometry-based point cloud compression (G-PCC)
algorithm by the Moving Picture Experts Group (MPEG), carried out for a variety
of point clouds, demonstrate that the proposed method achieves significantly
better results for small bit rates
Scalable coding of HDTV pictures using the MPEG coder
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 118-121).by Adnan Husain Lawai.M.S
Current video compression algorithms: Comparisons, optimizations, and improvements
Compression algorithms have evolved significantly in recent years. Audio, still image, and video can be compressed significantly by taking advantage of the natural redundancies that occur within them. Video compression in particular has made significant advances. MPEG-1 and MPEG-2, two of the major video compression standards, allowed video to be compressed at very low bit rates compared to the original video. The compression ratio for video that is perceptually lossless (losses can\u27t be visually perceived) can even be as high as 40 or 50 to 1 for certain videos. Videos with a small degradation in quality can be compressed at 100 to 1 or more; Although the MPEG standards provided low bit rate compression, even higher quality compression is required for efficient transmission over limited bandwidth networks, wireless networks, and broadcast mediums. Significant gains have been made over the current MPEG-2 standard in a newly developed standard called the Advanced Video Coder, also known as H.264 and MPEG-4 part 10. (Abstract shortened by UMI.)
Efficient compression of motion compensated residuals
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Improvement of MPEG-2 compression by position-dependent encoding
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (leaf 64).by Eric Reed.M.S
A Real-time Rate-distortion Oriented Joint Video Denoising and Compression Algorithm
This thesis proposes a real-time video denoising filter, a joint pre-filtering and compression algorithm, and a joint in-loop filtering and compression algorithm.
A real-time video denoising filter: a great number of digital video applications motivate the research in restoration or enhancement methods to improve the visual quality in the presence of noise. Video Block-Matching and 3D collaborative filter, abbreviated as VBM3D, is one of the best current video denoising filters. We accelerate this filter for real-time applications by simplifying the algorithm as well as optimizing the codes, while preserving its good denoising performance.
A joint pre-filtering and compression algorithm: pre-filtering and compression are two separate processes in traditional systems and they do not guarantee optimal filtering and quantization parameters with respect to rate-distortion framework. We propose a joint approach with pre-filtering by VBM3D and compression by H.264/AVC. For each quantization parameter, it jointly selects the optimal filtering parameter among the provided filtering parameters. Results show that this approach enhances the performance of H.264/AVC by improving subjective visual quality and using less bitrates.
A joint in-loop filtering and compression algorithm: in traditional video in-loop filtering and compression systems, a deblocking filter is employed in both the encoder and decoder. However, besides blocking artifacts, videos may contain other types of noise. In order to remove other types of noise, we add a real-time filter as an enhancing part in the H.264/AVC codec after the deblocking filter. Experiments illustrate that the proposed algorithm improves the compression performance of the H.264/AVC standard by providing frames with increased PSNR values and less bitrates. /Kir1
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