彩色成像系统最小可分辨色差测量方法研究

Measurement method of MRED of color imaging system

最小可分辨色差通常使用基于人眼观测的主观方法测量,精度不高。为了提高测量精度,利用人眼敏感度函数Barten模型建立起来一种客观测量模型。即彩色四杆靶图案被成像系统接收,经色彩空间变换、傅里叶变换、人眼敏感函数处理,当测试图案敏感度值与由人眼敏感度函数决定的人眼敏感度阈值相匹配时,将此时的图片转换到CIELAB颜色空间并计算色差,记录不同空间频率四杆靶的测试结果并与主观测量结果相比较。结果表明:基于人眼视觉模型的客观测量方法与主观测量方法所得结果相一致,即所提出的客观测量方法是可行的。

MRED with a low precision usually can be detected by a subjective way which is based on the human eye observation before. In order to improve the measurement accuracy, a new objective way based on the theory of Barten module was built, which was one model of Contrast Sensitivity Functions (CSF). Four-bar target pattern was received by color imaging system. After a series of processing such as color space conversion, Fourier transform and CSF processing, the chromatic aberration on the CIELAB color space was calculated when the chromatic aberration of the test pattern reached the threshold value determined by CSF. Both of the two results tested by the subjective and objective way on different spatial frequencies of the four-bar target were recorded and compared. The results show that the value got by the subjective measurement method is consistent with that of the objective. That means the subjective measurement method based on human visual model in this paper is desirable.