Software Design Of CMOS Image Sensor Performance Parameter Test System

CMOS image sensors(CIS)have greatly improved in terms of power consumption,size,and image quality with the development of basic circuit structures and CMOS integrated circuit processing technology.At present,CIS has been widely used in the fields of security protection,industrial measurement,aerospace,biomedicine,astronomical observation,commercial photography,etc.It has surpassed the charge coupled device CCD and has become the main body of imaging devices.With the deepening of CIS application technology,the measurement of CIS performance parameters has become more and more important.Based on the study of the European Machine Vision Association's general standard EMVA 1288 for image sensor and digital camera testing,this paper designs the overall scheme of the CIS performance parameter test system.The system generally includes three parts: the light source and control part,the CMOS digital camera to be tested,and the computer software.In order to obtain the high uniform surface light source necessary for the test system,from the practical point of view,a structural scheme of the outer cylinder of the integrating sphere light exit port to form a dark room is designed.In order to increase the uniformity of the output surface of the light source,the inner surface of the outer cylinder is designed with a certain structural thread.According to the optical principle,the surface light source structure is designed and simulated by optical simulation software ASAP,and the corresponding surface light source system is developed in the laboratory according to the simulation results.The experimental test results show that the uniformity of the circular surface light source with a diameter of 20 mm reaches 96%,each technical index is superior to the existing light source scheme,and has better practicability.Based on the hardware platform of CIS performance parameter test system developed in the laboratory,the matching test software is designed by using Visual Studio 2013 integrated development software and C++ programming language.The software is mainly divided into three major modules: interface interaction module,image acquisition control and receiving module,image processing and parameter calculation module.By studying the characteristics and measurement methods of temporal noise,a new method for measuring time noise,double frame characteristic method,is proposed,which reduces the measurement time and improves the stability of measurement results.In this paper,the software functions are described in detail,and the measurement functions of CIS photoelectric response curve,quantum efficiency,signal-to-noise ratio,dynamic range,temporal noise,dark current,spatial nonuniformity and other performance parameters are realized.Finally,the results are tested and analyzed,and the results show that the indicators meet the predetermined requirements.