A Deterministic Low-Complexity Approximate (Multiplier-Less) Technique for DCT Computation
A Deterministic Low-Complexity Approximate (Multiplier-Less) Technique for DCT Computation
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DOI：
10.1109/tcsi.2019.2902415
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发表时间：
2019-08-01
影响因子：
5.1
通讯作者：
Lombardi, Fabrizio
中科院分区：
文献类型：
--
作者：
Huang, Junqi;Kumar, T. Nandha;Lombardi, Fabrizio
近似（无乘法器）二维离散余弦变换（DCT）是广泛采用的图像/视频压缩技术。本文提出了一种确定性低复杂度近似DCT技术，该技术根据Z字形扫描过程中保留系数的数量精确配置变换矩阵（T）的大小。这是通过建立保留系数的数量和 T 矩阵的行数之间的关系来实现的。所提出的技术被称为锯齿形低复杂度近似 DCT (ZLCADCT)，与近似 DCT (ADCT) 相比，减少了加法运算的数量和能耗，同时保留了压缩图像的 PSNR。此外，ZLCADCT 消除了 ADCT 中使用的锯齿形扫描过程。此外，为了表征 ZLCADCT 的确定性操作，提供了详细的数学模型。然后利用基于 FPGA 的硬件平台对所提出的技术进行实验评估和比较；由于模块化、确定性、低延迟和可扩展性，所提出的技术可以在保留系数数量发生任何变化时通过实现针对额外所需硬件的FPGA资源的仅部分重新配置来实现。大量的仿真和实验结果表明，在不同指标下，与之前的 ADCT 技术相比，该技术具有优越的性能。
The approximate (multiplier-less) two-dimensional discrete cosine transform (DCT) is a widely adopted technique for image/video compression. This paper proposes a deterministic low-complexity approximate DCT technique that accurately configures the size of the transform matrix (T) according to the number of retained coefficients in the zigzag scanning process. This is achieved by establishing the relationship between the number of retained coefficients and the number of rows of the T matrix. The proposed technique referred to as the zigzag low-complexity approximate DCT (ZLCADCT), when compared with approximate DCT (ADCT), decreases the number of addition operations and the energy consumption while retaining the PSNR of the compressed image. In addition, the ZLCADCT eliminates the zigzag scanning process used in the ADCT. Moreover, to characterize the deterministic operation of the ZLCADCT, a detailed mathematical model is provided. A hardware platform based on FPGAs is then utilized to experimentally assess and compare the proposed technique; as modular, deterministic, low latency, and scalable, the proposed techniques can be implemented upon any change in the number of retaining coefficients by realizing only a partial reconfiguration of the FPGA resources for the additional required hardware. The extensive simulation and experimental results show the superior performance compared to previous ADCT techniques under different metrics.