Forward-reverse motion influence on CCD detectors imaging quality

Abstract

The relative motion to the CCD camera during the imaging course is becoming more and more prevalent. Especially when the objects are moving forwards or backwards at a high speed, the image's resolving power will decline rapidly from the center to the edge of each frame, which will deteriorate the imaging quality seriously. On the problem, in view of the use of grating with sine distributed intensity in the evaluation of static system's imaging quality, and considering that during the objects' forward-reverse motion, the magnification of optical image of the object is changing smoothly, a model of concentric circles with sine distributed intensity is built on the area CCD's photosensitive surface, the contrast of which is 100%. Using the concentric circles model, the paper has deduced the signal intensity and contrast expressions of each frame image during the objects' relative motion. Then the CCD detector's imaging quality can be evaluated by the signal intensity and contrast of each frame image. From the expressions, we can know that the concentric circle's radius, the object's spatial frequency's change rate and CCD's integration time will all influence the image's resolving power. Whichever parameter of the three increases, the contrast will decline by the function of |sinc|. On the basis of the theoretic analyse, the paper has given some pictures and graphs of the experimentation. The calculating data and pictures from the experimentation have verified the results of the theoretic analyse.