人眼的阈上调制传递函数

视觉系统的阈上调制传递函数与阈值对比敏感度函数具有明显的区别.但由于阈上测试方法复杂,因而迄今为止阈上调制传递函数的测试数据比阈值对比敏感度函数要少得多.我们应用传统的极限调节法和对比度比配法分别测试了人眼的阈值对比敏感度函数和三种对比度级别的阈上调制传递函数.测试结果表明,一个以DOG(Difference of two Gaussians)函数为基础的函数是一种合理的模型,可由现有阈值对比敏感度函数预测不同对比度和象场亮度级别下的人眼阈上调制传递函激.这个模型也可做为一种有效的人眼生理光学经验公式,用于目视光电成象系统的设计和象质评价.

SUPRATHRESHOLD MODULATION TRANSFER FUNCTION(SMTF) OF THE HUMAN VISUAL SYSTEM

Suprathreshold modulation transfer function (SMTF) of the human visual system measured at contrasts well above threshold differs significantly from contrast sensitivity function (CSF). Fewer MTF data at suprathreshold contrasts have been measured than at threshold because of the complexity of the measurement method . SMTF at three contrast levels and CSF measured in our lab using contrast matching method and limit method , respectively . The results reveal that a DOG-based function is a reasonable model to predict SMTF at different contrasts and luminance levels from existed CSF data . This model can also be thought of as a powerful empirical formula of the human physiological optics for optoelectronic imaging system design and image evaluation .