463 research outputs found

    Extending JPEG-LS for low-complexity scalable video coding

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    An overview of JPEG 2000

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    JPEG-2000 is an emerging standard for still image compression. This paper provides a brief history of the JPEG-2000 standardization process, an overview of the standard, and some description of the capabilities provided by the standard. Part I of the JPEG-2000 standard specifies the minimum compliant decoder, while Part II describes optional, value-added extensions. Although the standard specifies only the decoder and bitstream syntax, in this paper we describe JPEG-2000 from the point of view of encoding. We take this approach, as we believe it is more amenable to a compact description more easily understood by most readers.

    Resource-Constrained Low-Complexity Video Coding for Wireless Transmission

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    Scalable video

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    Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 51).This thesis presents the design and implementation of a scalable video scheme that accommodates the uncertainties in networks and the differences in receivers' displaying mechanisms. To achieve scalability, a video stream is encoded into two kinds of layers, namely the base layer and the enhancement layer. The decoder must process the base layer in order to display minimally acceptable video quality. For higher quality, the decoder simply combines the base layer with one or more enhancement layers. Incorporated with the IP multicast system, the result is a highly flexible and extensible structure that facilitates video viewing to a wide variety of devices, yet customizes the presentation for each individual receiver.by Ying Lee.M.Eng

    Kompresi Citra Digital dengan menggunakan Metode Quadro, Discrete Wavelet Transform (DWT) dan Run Length Encoding (RLE)

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    ABSTRAKSI: Kompresi citra digital merupakan salah satu metoda dalam pengolahan citra yang berfungsi untuk mengurangi ukuran data citra murni yang besar dengan cara mengurangi informasi (lossy) atau tetap mempertahankannya (lossless). Pada tugas akhir ini dikembangkan suatu metode kompresi citra digital yang menggabungkan Quadro,Discrete Wavelet Transform (DWT) dan Run Length Encoding (RLE). Penerapan prinsip segmentasi citra dalam penghentian Quadro dan dilanjutkan dengan metode DWT yang menghasilkan citra dengan kombinasi nilai intensitas yang jauh lebih sederhana dengan hanya mengambil nilai pentingnya saja (subband LL). Hanya nilai penting ini yang kemudian digunakan pada proses inverse DWT (IDWT) dan dilanjutkan dengan proses threshold untuk mendapatkan keseragaman nilai pada pixel-pixel tetangga. Sehingga akan menghasilkan nilai rasio kompresi yang lebih besar setelah proses RLE.Kata Kunci : Quadro, DWT, Threshold, RLEABSTRACT: Digital image compression is one of method that used in image processing to reduce storage size of image by reduce it information (lossy) or remain to maintain it (lossless). In this final task, the digital image compression has developed by combining methods of Quadro, Discrete Wavelet Transform (DWT) and Run Length Encoding (RLE). Using the image segmentation in stopping the Quadro and then continued by implemented the DWT method which would result a simpler combination value of image’s color intensity with only saving the important value of an image (in subband LL). Then, using only this important value but zero-ing others subband, the process continued to the inverse of DWT and then threshold method to get homogeneous values within the neighbor pixels. Thus, it will end with greater value of compression ratio which is done by the RLE.Keyword: Quadro, DWT, Threshold, RL

    Algorithms for compression of high dynamic range images and video

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    The recent advances in sensor and display technologies have brought upon the High Dynamic Range (HDR) imaging capability. The modern multiple exposure HDR sensors can achieve the dynamic range of 100-120 dB and LED and OLED display devices have contrast ratios of 10^5:1 to 10^6:1. Despite the above advances in technology the image/video compression algorithms and associated hardware are yet based on Standard Dynamic Range (SDR) technology, i.e. they operate within an effective dynamic range of up to 70 dB for 8 bit gamma corrected images. Further the existing infrastructure for content distribution is also designed for SDR, which creates interoperability problems with true HDR capture and display equipment. The current solutions for the above problem include tone mapping the HDR content to fit SDR. However this approach leads to image quality associated problems, when strong dynamic range compression is applied. Even though some HDR-only solutions have been proposed in literature, they are not interoperable with current SDR infrastructure and are thus typically used in closed systems. Given the above observations a research gap was identified in the need for efficient algorithms for the compression of still images and video, which are capable of storing full dynamic range and colour gamut of HDR images and at the same time backward compatible with existing SDR infrastructure. To improve the usability of SDR content it is vital that any such algorithms should accommodate different tone mapping operators, including those that are spatially non-uniform. In the course of the research presented in this thesis a novel two layer CODEC architecture is introduced for both HDR image and video coding. Further a universal and computationally efficient approximation of the tone mapping operator is developed and presented. It is shown that the use of perceptually uniform colourspaces for internal representation of pixel data enables improved compression efficiency of the algorithms. Further proposed novel approaches to the compression of metadata for the tone mapping operator is shown to improve compression performance for low bitrate video content. Multiple compression algorithms are designed, implemented and compared and quality-complexity trade-offs are identified. Finally practical aspects of implementing the developed algorithms are explored by automating the design space exploration flow and integrating the high level systems design framework with domain specific tools for synthesis and simulation of multiprocessor systems. The directions for further work are also presented

    Image and Video Coding Techniques for Ultra-low Latency

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    The next generation of wireless networks fosters the adoption of latency-critical applications such as XR, connected industry, or autonomous driving. This survey gathers implementation aspects of different image and video coding schemes and discusses their tradeoffs. Standardized video coding technologies such as HEVC or VVC provide a high compression ratio, but their enormous complexity sets the scene for alternative approaches like still image, mezzanine, or texture compression in scenarios with tight resource or latency constraints. Regardless of the coding scheme, we found inter-device memory transfers and the lack of sub-frame coding as limitations of current full-system and software-programmable implementations.publishedVersionPeer reviewe

    A practical comparison between two powerful PCC codec’s

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    Recent advances in the consumption of 3D content creates the necessity of efficient ways to visualize and transmit 3D content. As a result, methods to obtain that same content have been evolving, leading to the development of new methods of representations, namely point clouds and light fields. A point cloud represents a set of points with associated Cartesian coordinates associated with each point(x, y, z), as well as being able to contain even more information inside that point (color, material, texture, etc). This kind of representation changes the way on how 3D content in consumed, having a wide range of applications, from videogaming to medical ones. However, since this type of data carries so much information within itself, they are data-heavy, making the storage and transmission of content a daunting task. To resolve this issue, MPEG created a point cloud coding normalization project, giving birth to V-PCC (Video-based Point Cloud Coding) and G-PCC (Geometry-based Point Cloud Coding) for static content. Firstly, a general analysis of point clouds is made, spanning from their possible solutions, to their acquisition. Secondly, point cloud codecs are studied, namely VPCC and G-PCC from MPEG. Then, a state of art study of quality evaluation is performed, namely subjective and objective evaluation. Finally, a report on the JPEG Pleno Point Cloud, in which an active colaboration took place, is made, with the comparative results of the two codecs and used metrics.Os avanços recentes no consumo de conteúdo 3D vêm criar a necessidade de maneiras eficientes de visualizar e transmitir conteúdo 3D. Consequentemente, os métodos de obtenção desse mesmo conteúdo têm vindo a evoluir, levando ao desenvolvimento de novas maneiras de representação, nomeadamente point clouds e lightfields. Um point cloud (núvem de pontos) representa um conjunto de pontos com coordenadas cartesianas associadas a cada ponto (x, y, z), além de poder conter mais informação dentro do mesmo (cor, material, textura, etc). Este tipo de representação abre uma nova janela na maneira como se consome conteúdo 3D, tendo um elevado leque de aplicações, desde videojogos e realidade virtual a aplicações médicas. No entanto, este tipo de dados, ao carregarem com eles tanta informação, tornam-se incrivelmente pesados, tornando o seu armazenamento e transmissão uma tarefa hercúleana. Tendo isto em mente, a MPEG criou um projecto de normalização de codificação de point clouds, dando origem ao V-PCC (Video-based Point Cloud Coding) e G-PCC (Geometry-based Point Cloud Coding) para conteúdo estático. Esta dissertação tem como objectivo uma análise geral sobre os point clouds, indo desde as suas possívei utilizações à sua aquisição. Seguidamente, é efectuado um estudo dos codificadores de point clouds, nomeadamente o V-PCC e o G-PCC da MPEG, o estado da arte da avaliação de qualidade, objectiva e subjectiva, e finalmente, são reportadas as actividades da JPEG Pleno Point Cloud, na qual se teve uma colaboração activa
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