一句话：利用人眼颜色辨别局限与周边视觉特性，在VR中通过感知无损的有损压缩降低DRAM访问能耗。
VR有望成为下一代普适计算平台，但其DRAM访问能耗占系统能耗很大比例。现有帧缓冲压缩采用数值无损算法，却忽略了人类感知并不要求数值无损。本文提出一种感知无损、数值有损的DRAM流量压缩系统：基于心理物理学中人类难以分辨相近颜色、且周边视觉辨别力更弱的特性，算法调整像素颜色以最小化位编码开销且不引入可见伪影，并配以轻量体系结构支持实时运行。评估表明，该系统将DRAM流量降低66.9%，比现有帧缓冲压缩机制最高提升20.4%，人类被试的心理物理学研究显示几乎不造成感知保真度下降。
Virtual Reality (VR) has the potential of becoming the next ubiquitous computing platform. Continued progress in the burgeoning field of VR depends critically on an efficient computing substrate. In particular, DRAM access energy is known to contribute to a significant portion of system energy. Today's framebuffer compression system alleviates the DRAM traffic by using a numerically lossless compression algorithm. Being numerically lossless, however, is unnecessary to preserve perceptual quality for humans. This paper proposes a perceptually lossless, but numerically lossy, system to compress DRAM traffic. Our idea builds on top of long-established psychophysical studies that show that humans cannot discriminate colors that are close to each other. The discrimination ability becomes even weaker (i.e., more colors are perceptually indistinguishable) in our peripheral vision. Leveraging the color discrimination (in)ability, we propose an algorithm that adjusts pixel colors to minimize the bit encoding cost without introducing visible artifacts. The algorithm is coupled with lightweight architectural support that, in real-time, reduces the DRAM traffic by 66.9% and outperforms existing framebuffer compression mechanisms by up to 20.4%. Psychophysical studies on human participants show that our system introduce little to no perceptual fidelity degradation.
DOI 原文 · arXiv · PDF（开放获取） · DBLP
@inproceedings{abs-2310-00441,
title = {Exploiting Human Color Discrimination for Memory- and Energy-Efficient Image Encoding in Virtual Reality},
author = {Nisarg Ujjainkar and Ethan Shahan and Kenneth Chen and Budmonde Duinkharjav and Qi Sun and Yuhao Zhu},
booktitle = {ASPLOS},
year = {2024},
doi = {10.1145/3617232.3624860}
}