A New CMTF Evaluation Model for Dynamic Target in Photoelectric Imaging System

摘要

To evaluate the reliability of photoelectric imaging system, it is essential to research the influences of the illumination contrast and the modulation transfer functions (MTF) to the system imaging capability. This paper deduces a new illumination contrast model based on the optical geometry structure and the optical reflection characteristics of dynamic target; according to the photoelectric imaging principle, defines the system's MTF by the form of some imaging links, including the optical characteristics, the CCD detector, and the atmospheric characteristics; establishes a new contrast modulation transfer functions (CMTF) mathematical model based on the analysis of the illumination contrast and MTF; obtains the expression of magnitude to evaluate the effects of some key factors to imaging capability. Through the calculation and analysis, under various conditions, with the increasing of target reflectivity, relative aperture, atmospheric coherence length, and optical transmittance, the system imaging capability shows a general trend of rising; with the increasing of background radiation illumination, target distance, standard deviation, and the system imaging capability shows attenuation trend; the results show that different factors have a great impact on the imaging capability, which proves the suitability of CMTF model for evaluating the performance photoelectric system.