眩光变量与有效对比度关系曲线方程的建立与分析

Establishment and Analysis on Curve Equation about Relation between Glare Variables and Effective Contrast

目的建立一定对比的视标在人眼光亮度有效感知区和眩光影响下的有效对比度的曲线方程。方法假定人眼有生理光亮度有效感知区,用极限值(明阈值与暗阈值)来量化表示,结合眩光变量,在迈克逊的对比度公式基础上,分析各种条件下的适用曲线方程,进行一般二次曲线的不变量判别和计算后,建立分段曲线方程组。结果 6个分段曲线方程构成两幅无缝接壤曲线图,3种条件下呈一直线,另3个条件下都是双曲线。结论眩光变量与有效对比度关系曲线方程组可用于计算多因素影响下的视标有效对比度,再通过与相同背景适应光下测定的对比敏感函数对照就可以知道相应的有效视力。

Objective To establish the curve equation about the relationship between glare variables and effec- tive contrast as watching a visual target in physiological luminance-sensitive zone. Methods A supposed physi- ological luminance-sensitive zone of human eye was quantified with dark threshold and bright threshold in physical indices. Based on the Michelson definition of contrast, with analysis on suitable curve equations in various conditions and mathematical calculations of unvariable discrimination in general quadric curves, the segment curve equations about the relation between glare variables and effective contrast were established. Re- suits Six equations of curves were composed of two complete curves, which showed one straight line in three conditions and one hyperbola in the other three conditions. Conclusion The curve equations about the relation between effective contrast and glare variables can be used to calculate effective contrast of visual target affected by many factors and to forecast efficient vision on the basis of contrast sensitivity function measured in the same background light.