最小可觉差是人眼视觉重要特性之一, 随着计算机显示器的普及, 显示器环境下的亮度最小可觉差对图像细节有重要的应用价值。利用10 bit图像显示卡和液晶显示器方便、精确控制亮度刺激, 在显示器显示亮度范围内产生27个不同亮度背景, 采样心理物理学亮度视觉匹配实验测得亮度最小可觉差。实验结果表明, 在背景亮度为11.89～142.3 cd/m2中等亮度下人眼最小可觉差与背景亮度的比值约为0.017, 并遵守韦伯定律; 在背景亮度为0.38～9.36 cd/m2的弱亮度情况下, 人眼最小可觉差与背景亮度的比值随亮度的增加呈单调递减趋势。在显示器上测量的中等亮度下人眼亮度最小可觉差与Koenig and Brodhun采用传统光学方法得到的实验结果基本一致。

The just noticeable difference (JND) in luminance is one of important characteristics of the human visual system (HVS). With the popularity of computer display, the JND in luminance has important application value for viewing the image details under the computer display environment. In this paper, generated luminance stimuli using liquid crystal display (LCD) with 10 bit graphic card, the JND for 27 background luminances were measured by the psychophysical experiment on luminance matching. Experimental results show that the ratio of the JND and background luminance is about 0017 at the moderate background luminance from 1189 cd/m2 to 142.3 cd/m2, that follows the Weber’s law, and the ratio of the JND and background luminance is decreased with increase of the background luminance at lower background luminance from 0.38 cd/m2 to 9.36 cd/m2. The measured results of JND for luminance of human visual system on liquid crystal display under moderate background luminance are consistent with Koenig and Brodhun’s results using traditional method.