Point cloud based 3D visual representation is becoming popular due to its ability to exhibit the real world in a more comprehensive and immersive way. However, under a limited network bandwidth, it is very challenging to communicate this kind of media due to its huge data volume. Therefore, the MPEG have launched the standardization for point cloud compression (PCC), and proposed three model categories, i.e., TMC1, TMC2, and TMC3. Because the 3D geometry compression methods of TMC1 and TMC3 are similar, TMC1 and TMC3 are further merged into a new platform namely TMC13. In this paper, we first introduce some basic technologies that are usually used in 3D point cloud compression, then review the encoder architectures of these test models in detail, and finally analyze their rate distortion performance as well as complexity quantitatively for different cases (i.e., lossless geometry and lossless color, lossless geometry and lossy color, lossy geometry and lossy color) by using 16 benchmark 3D point clouds that are recommended by MPEG. Experimental results demonstrate that the coding efficiency of TMC2 is the best on average (especially for lossy geometry and lossy color compression) for dense point clouds while TMC13 achieves the optimal coding performance for sparse and noisy point clouds with lower time complexity.
The DArk Matter Particle Explorer (DAMPE) is a high-energy cosmic ray and gamma-ray detector located in space. Over a period of seven years since its launch on December 17, 2015, DAMPE has surveyed the entire sky and collected an extensive dataset of more than 300,000 photons with energies above 2 GeV. To analyze the gamma-ray data obtained by DAMPE, instrument response functions (IRFs) have been derived, and a specialized software called DmpST has been developed. In this context, we present the results of the DAMPE gamma-ray point-like source catalog. This catalog provides valuable information about the detected gamma-ray sources, which includes details such as the positions, energy spectra, and flux measurements of these point-like gamma-ray sources. By studying these sources, scientists can gain insights into various astrophysical phenomena, including the emission processes and distribution of gamma-ray sources in the universe.
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