Design And Calibration Of The Contrast Targets For Human Eye Threshold Measurement

Eyes, known as the "window o f the soul", are very important in our daily life. People use them to observe the world and find the world. From the physical level, the human eye is the ultimate receiver of the image, and the instrument of all optical imaging is the assistant tool of the human eye. Since their services, when the visual characteristics of these optical instruments into the image to match the human eye, the information that people get is true and reliable. Contrast threshold characteristic is an important parameter to measure human eye visual characteristics of space, but also an important basis for the diagnosis of eye diseases. At present, people are using the contrast sensitivity function to represent the human eye contrast threshold measurement results. Contrast sensitivity function is the theoretical basis of the evaluation of the optical system, an image display and other treatment technologies.This paper presents a co ntrast target generating device, which can generate different contrast observation test charts in different background luminance and spatial frequency. Based on the measuring principle of this system, this paper presents an effective method of adjusting the contrast pattern. In this way, after a lot of experiments, we generate the contrast pattern of 8 different spatial frequencies during the day and night. Each spatial frequencies has 9contrast pattern, and finally we get 144 patterns. We have done a lot of the repeatability and reproducibility experiments about the contrast pattern. The results showed that the repeatability and reproducibility of the system reach the postulate of test. The test results of this system in the Excel spreadsheet gives a contrast sensitivity function curve of the subject’s eyes, and the result can provide an effective basis for early diagnosis of eye disease.