针对环境光对移动终端显示内容室外可读性的影响，以及移动终端设备亮度与环境光的相关性，用液晶显示器(LCD)的移动终端测量了人眼恰可察觉明度阈值。在不同环境光照度，不同设备亮度下，观察不同空间频率和不同平均明度的正弦灰色条纹，记录恰可察觉明度阈值。分析了环境光对不同频率和不同平均明度条纹的恰可察觉明度阈值的影响，建立了简易环境光对比度与恰可察觉明度阈值模型。结果表明：环境光的影响与条纹的人眼对比敏感度成反比，所建模型可得到较为明确的函数关系，该研究成果可适用于不同环境光下移动终端亮度的优化设置。

A mobile terminal-based method is established for testing the influence of ambient light on outdoor readability and the relevance of device brightness and ambient light. Gray sinusoidal fringes of different frequencies and different brightness centers are observed under different ambient light and different device brightness. According to the recorded just-noticeable lightness threshold, the influence of ambient light on the just-noticeable lightness threshold is analyzed and the model of simplified ambient contrast and just-noticeable lightness threshold is established. The results show that the influence of ambient light is inversely proportional to the contrast sensitivity of the observed sinusoidal fringes. A quite specific function can be got by the model and it can be applied to the setting of the device brightness under different ambient light.