人眼动态视觉特性分析

Dynamic Visual Function Analysis of Human Eyes

人眼作为电视系统的接收终端，其视觉特性直接决定着对电视系统的特性要求；也是对电视图象信号进行频带压缩处理的基础．本文基于人眼的视觉特性，提出了人眼视觉响应模型．分析了人眼动态视觉特性，分析表明．由于视觉残留的影响，人眼对活动图象的空间分辨力将降低，而对时变图象则表现为对层次的分辨力下降，其结果都降低了对单幅图象的有效息信量，从而为对视频图象信号的频带压缩提供了可能；而对电视系统来说，传送静止图象所需的比特率最低，而且随着图象静止时间的增加而趋近于零．

Human eyes as the receive end terminals of the TV systems, their function not only decide the property requirements for TV systems, but also take place as the bases of frequency band compress for TV image signals.This paper based on the visual function of human eyes, the human visual response model and corresponding visual properties are suggested and analysed.Analysis results show: Because of the linfluence of persistance of human vision, the spatial resolution of human eye will be decreased for moving objects, and the amplitude resolution will be decreased for time-variant images, both the results decrease the effective information of image signals,and supply the possibility to make frequency compress for TV image signals.In the TV transmission case, the necessary bit rate is minimal for a static image, and tend to zero when the static time increased.