Research On The Modulation Transfer Function Test Technology Of Low-light-level Image Intensifiers

Low-Level-Light(LLL)image intensifier is the core component of the Low-Level-Light(LLL)night vision,the quality of its image directly affect the clarity of the image.Modulation transfer function(MTF)is recognized as the most comprehensive,objective and effective method to evaluate the image quality of imaging system.In this paper,we focus on the study of the test technology of MTF and develop a testing system of the MTF for the LLL image intensifier.First of all,the paper introduces developing process,working principle of LLL image intensifier,and related performance evaluation parameters,and also describes the research background,and explains the main work of this paper.Secondly,the test system adopts the digital Fourier test method which takes the cross slit as the target based on the studying of the basic theory of MTF and the test methods commonly used.According to the test method,a hardware platform which consists of target light source system,image acquisition system and focus control system for testing the modulation transfer function of LLL image intensifier is established.Then,we design the test software with the image capture card SDK,TeeChart draw control,OPENCV,and MATLAB in the Visual Studio 2010.The four parts of the test software are image acquisition module,focus control module,MTF calculation module and the document management module respectively.The joint test of the hardware and software is realized.Next,the paper accomplished the tesing experiments,and the result from the MTF test on LLL image intensifier shows that the test system can realize MTF test on LLL image intensifier in two different directions,and the test frequency can reach 0-100 lp/mm and the test system performs stably with the repeatability better than 5%.Finally,we carry out the error analysis on the possible problems of the test system and propose the further work directions.