Research On MTF Measurement System Based On C8051F340

MTF (Modulation Transfer Function) is recognized as one of the most objective andeffective methods to evaluate the optical imaging system, because MTF can veritablyreflect characteristics of spatial frequency response of the system. With the development ofcomputer technology, photoelectric detection devices and image processing technology,MTF measurement technique is also in progress. So MTF measurement technique isdeeply researched in the paper, MTF measurement technique based on special object imageanalyzing is proposed, and it has been applied in the quality detection system of opticallenses.This paper is on the basis of special object image analyzing, by using slant edge asobject and CMOS sensor as device of image analyzing to get edge spread function of theimage, the noise has been suppressed to use self-adaptive algorithm. And the MTF of thelens is got to use differential operation and Fourier transform. This method has theadvantage that optical structure is simple and data processing is easy. The methodovercomes the disadvantages of sampling aliasing, energy deficiency and noiseinterference. The hardware of this system uses OV7670and C8051F340to obtain theimage and transfer the image. the design of USB communication system is implementedbased on MCU C8051F340. And then based on the hardware circuit, I program thefirmware procedure of system. Graphic interface of PC software is programmed by C#,and MTF algorithm is programmed by MATLAB, it has been judged the test results of thelens imaging quality.The whole system is stable by the results of experiment. The obtained values and thetheoretical value of IMATEST simulation are compared in the lower spatial frequenciesthat the error controls in less than3%. So the testing system is structured simply and calculated easily. The system well fits the MTF measurement of the optical imagingsystem and can be applied into practical application.