Cmos Sensor-based Full Field Mtf Measurement System

In this paper a system using CMOS imaging technique is proposed to evaluate quickly the imaging quality of lens on the basis of Fourier Optics. By using knife edge as object,and CMOS sensor as device for image analyzing,we get edge spread function from the image and use differential operation and FFT to obtain modulation transfer function of the lens,then its image quality is known. For different focus lenses,we realize auto-measuring by focusing. The methods to improve the precision of measurement are also discussed.The hardware and the software of the proposed system are expatiated. The hardware mainly includes lighu image sensor image card RS232 interface and the driving circuits of the stepping motor. The software consists of video and image processing software RS232 communication software and the embedded software for driving the stepping motor. The functionality and precision of the system are discussed on the basis of experimental results.The paper also briefs how to improve the performance of the proposed testing system in the future.