Microcomputer Controlled MTF Measuring Equipment for Infra-red and Visible Wavelengths

An operational MTF measuring bench operating in both visible and infra-red regions is described. Measurements can be made at both room and climatic chamber temperatures. The basic mathematics for measuring the MTF from the edge spread function (ESF) or from the line spread function (LSF) are given. Optimal criteria for the measurement are derived taking into account the spatial sampling frequency and spectral resolution. The results obtained with standard lenses are compared with theoretical calculations. The microcomputer software has been optimized in order to give the result in form of graphs in a few seconds. If also provides options for measuring focal lengths or magnification, distortion, field curvature and transmission