Measurement and analysis of modulation transfer function of digital image sensors

With the ceaseless development of technology, optical imaging systems have been extensively used in numerous different fields. As a result, verifying the performance of such systems has taken on significant importance. To test these systems, a commonly used metric is the modulation transfer function (MTF) because it reflects the spatial-frequency response of optical systems. To determine how best to measure the MTF of an image sensor, we use the slanted-knife-edge method to measure optical patterns and a black-and-white face sensor to receive patterns, following which we numerically calculate the MTF. We use the MTF of the Nyquist frequency (50 lp/mm) of an image sensor as the measured value, and the slanting angle for the slanted-knife-edge method ranges from 2 degrees to 10 degrees, which is known to provide accurate results. We then compare and analyze the experimental data and explore how inaccurate slanting angles affect the measured MTF. Finally, we propose a "program correction method" in which we input a corrected slanting angle into the region-of-interest program to correct for errors in the measurement of the MTF. The corrected parameters provide a more accurate measurement of the MTF of the given pattern.