Dependence of incoherent system response on object contrast.

A relationship between the image contrast and the object contrast for a general periodic or a truncated periodic object is derived. The result is illustrated for a periodic object of rectangular wave profile. It has been shown that for a truncated sine wave object the image contrast bears a nonlinear relationship to the object contrast. The contrast dependence of the measured or the apparent transfer function defined as the ratio of the image contrast to object contrast has been investigated.