A Low-Complexity Screen Compression Scheme for Interactive Screen Sharing
A Low-Complexity Screen Compression Scheme for Interactive Screen Sharing
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DOI：
10.1109/tcsvt.2013.2243056
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发表时间：
2013-06
影响因子：
8.4
通讯作者：
Zhaotai Pan;Huifeng Shen;Yan Lu;Shipeng Li;Nenghai Yu
中科院分区：
文献类型：
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作者：
Zhaotai Pan;Huifeng Shen;Yan Lu;Shipeng Li;Nenghai Yu
交互式屏幕共享需要极低延迟的端到端传输，这反过来又需要高效和低复杂度的屏幕压缩。本文提出了一种基于块的低复杂度屏幕压缩方案，其中采用多种块模式来利用帧内和帧间冗余。特别是，我们使用建议的快速块分类算法，利用图片和文本块之间的区别性功能的帧内编码块的图片块和文本块进行分类。然后，我们设计了一个低复杂度，但有效的，算法来压缩文本块。我们使用基色和转义色来表示和替换文本像素，这样不仅达到了高压缩比，而且还保持了高质量的文本像素。二维预测索引编码和分层模式编码技术分别用于利用局部空间相关性和全局模式相关性。为了进一步利用亮度和色度通道之间的相关性，我们提出了一种联合通道索引编码方法。我们比较的编码效率和所提出的方案对标准的图像编码方案，如JPEG，JPEG2000，PNG，复合图像压缩器HJPC，和流行的视频编码标准H.264的计算复杂度。我们还比较了H.264帧内编码，JPEG2000，和HJPC的视觉质量的建议方案。评估结果表明，所提出的方案实现了上级或可比的压缩效率与低得多的复杂度比其他方案在大多数情况下。
Interactive screen sharing requires extremely low latency end-to-end transmission, which in turn requires highly efficient and low-complexity screen compression. In this paper, we present a block-based low-complexity screen compression scheme, in which multiple block modes are adopted to exploit the intra- and inter-frame redundancies. In particular, we classify the intra-coded blocks to pictorial blocks and textual blocks using a proposed fast block classification algorithm, which exploits the discriminative features between the pictorial and the textual blocks. Then, we design a low-complexity, yet efficient, algorithm to compress the textual blocks. We use base colors and escape colors to represent and quantize the textual pixels, which not only achieves high compression ratios but also preserves a high quality on textual pixels. The two-dimensionally predictive index coding and hierarchical pattern coding technologies are used to exploit local spatial correlations and global pattern correlation, respectively. To further utilize the correlation between the luminance and chrominance channels, we propose a joint-channel index coding method. We compare the coding efficiency and the computational complexity of the proposed scheme against the standard image coding schemes such as JPEG, JPEG2000, and PNG, the compound image compressor HJPC, and the popular video coding standard H.264. We also compare the visual quality of the proposed scheme against H.264 intra coding, JPEG2000, and HJPC. The evaluation results show that the proposed scheme achieves superior or comparable compression efficiency with much lower complexity than other schemes in most of the cases.