Calculating the modulation transfer function of an optical imaging system incorporating a digital camera from slanted-edge images captured under variable illumination levels: Fourier transforms application using MATLAB

In this paper, a method for evaluating the modulation transfer function (MTF) of an optical system from the image of a slanted-edge target projected using an off-axis Newtonian collimator and recorded using a digital camera is presented. Mathematical derivation for the MTF function in terms of the line spread function employing Fourier transforms and convolution theory is provided. Furthermore, MATLAB® script for calculating the MTF plot from the captured slanted-edge images is given. As an illustration, MTF plots computed for slanted-edge images captured under 100, 500 and 1000lx illumination levels are discussed.