Modulation transfer function evaluation of charge-coupled-device camera system based on liquid crystal display random targets

In order to overcome the sampling-scene phase effect in the modulation transfer function (MTF) measurement of sampled imaging systems, a method using a pseudorandom number generating algorithm to generate several random targets displayed on a liquid-crystal-display(LCD) graph generator to evaluate the MTF of charge-coupled device(CCD) in visible region is discussed. The major advantages of this technique are that it has been demonstrated as a shift-invariant method without requiring mechanical scanning, and it is easy to generate a large number of random targets on LCD by computer program to get the average result and reduce measurement noise. By experiments, this technique has got a reliable MTF result and agrees with the usual methods. This method is expected to be used to develop a real-time video MTF testing software system.