MTF measurement of CCD digital camera based on improved slanted-edge method

An improved method was presented based on the slanted-edge method. It uses the Canny algorithm to detect edge in the acquired image, and calculates the high threshold which is significant to the Canny algorithm by using the Otsu algorithm combined with the bimodal characteristics of the edge image histogram. The centroid of each row is regarded as the center of edge spread function (ESF), then the two-dimensional edge data sampled with subpixel spacing from a region along the direction of the detected edge is reprojected to a one-dimensional array of sub-pixel bins, the ESF is obtained after averaging under improving the sampling rate. It increases the signal-to-noise ratio of the measurement. We used this method to test the modulation transfer function (MTF) of charge couple-device (CCD) camera in the laboratory, and analyzed the influences of parameter settings on accuracy of the MTF measurement.Result shows that the relative errors between the theoretical values and the experimental results are within 5%.