Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974, USA.
IEEE Trans Image Process. 2001;10(7):977-92. doi: 10.1109/83.931092.
Previously, fovcated video compression algorithms have been proposed which, in certain applications, deliver high-quality video at reduced bit rates by seeking to match the nonuniform sampling of the human retina. We describe such a framework here where foveated video is created by a nonuniform filtering scheme that increases the compressibility of the video stream. We maximize a new foveal visual quality metric. the foveal signal-to-noise ratio (FSNR) to determine the best compression and rate control parameters for a given target bit rate. Specifically, we establish a new optimal rate control algorithm for maximizing the FSNR using a Lagrange multiplier method defined on a curvilinear coordinate system. For optimal rate control, we also develop a piecewise R-D (rate-distortion)/R-Q (rate-quantization) model. A fast algorithm for searching for an optimal Lagrange multiplier lambda* is subsequently presented. For the new models, we show how the reconstructed video quality is affected, where the FSNR is maximized, and demonstrate the coding performance for H.263,+,++/MPEG-4 video coding. For H.263/MPEG video coding, a suboptimal rate control algorithm is developed for fast, high-performance applications. In the simulations, we compare the reconstructed pictures obtained using optimal rate control methods for foveated and normal video. We show that foveated video coding using the suboptimal rate control algorithm delivers excellent performance under 64 kb/s.
先前已经提出了一些针对注视点的视频压缩算法，这些算法在某些应用中通过寻求匹配人眼视网膜的非均匀采样，以较低的比特率提供高质量的视频。我们在这里描述了这样一个框架，其中通过非均匀滤波方案创建注视点视频，该方案增加了视频流的可压缩性。我们最大化了新的注视点视觉质量度量，即注视点信噪比（FSNR），以确定给定目标比特率下最佳的压缩和率控制参数。具体来说，我们使用定义在曲线坐标系上的拉格朗日乘子方法建立了一种新的最优率控制算法，以最大化 FSNR。对于最优的率控制，我们还开发了一种分段 R-D（率失真）/R-Q（率量化）模型。随后提出了一种用于搜索最优拉格朗日乘子 lambda*的快速算法。对于新模型，我们展示了如何在最大化 FSNR 的情况下影响重建视频质量，并演示了 H.263、++/MPEG-4 视频编码的编码性能。对于 H.263/MPEG 视频编码，我们开发了一种次优的率控制算法，用于快速、高性能的应用。在模拟中，我们比较了使用注视点和正常视频的最优率控制方法获得的重建图片。我们表明，使用次优率控制算法的注视点视频编码在 64kb/s 以下可提供出色的性能。
