The Research Of CMOS Image Sensor Testing Technology In Dark Field Based On Genetic Algorithm

Image sensors have been widely used in high-speed,ultra-high resolution,medical,military and aerospace areas.Especially in the aerospace,satellite telemetry and other aerospace applications,the test of image sensor key performance indicators is a necessary link to ground quality assurance.The general testing standard of image sensor mainly uses the gray signal and intensity data of image sensor to analyze the noise characteristics,and gets the main parameters of the image sensor.It is the premise of ensuring the normal operation of the image sensor to test the main parameters of the image sensor reasonably and steadily.The Photon Transfer theory is the basic theory to describe the relationship between signal and noise of image sensors,and also an important theoretical basis for the measurement of image sensors.The software and algorithm in this paper was designed mainly based on Photon Transfer theory and EMVA standard 1288.By analyzing the relationship between the gray data output from the image sensor and the noise signal,the performance parameters such as system gain,dark current,initial dark signal mean value and initial dark signal variance are measured.And only use the dark field gray data can be carried out on the image sensor performance parameters of the test,so that the test is simple.This paper summarizes the research status of domestic and foreign development situation of image sensor and test work,introduces the characteristics of dark field test and the test methods of bright field test.Then the photon transfer theory is systematically described.The main noise in the process of image sensor testing is introduced.The relationship between the noise signal and the gray signal of the output of the image sensor is analyzed according to the theory of Photon Transfer.The mathematical model required for dark field testing is obtained.At the same time,the adaptive genetic algorithm is analyzed and the test method of performance parameters of CMOS image sensor combined with dark field test mathematical model is designed.The paper also designs the test system of image sensor under dark field,and the test software is designed according to the mathematical model of adaptive genetic algorithm and dark field test.Through the experiment analysis,this test method can invert the performance parameters of CMOS image sensor,compared with the field test by method with genetic algorithm and dark curve transformation method,confirmed the validity of this test method.Dark field test without capturing bright field gray data,from the principle to avoid the effect of noise on the bright field data measurement,higher accuracy,at the same time,dark field testing process is relatively simple,convenient for long-term on-line observation,especially suitable for image sensor dynamic burn-in test under complex environment.