Calibration method for visual mark displayed on terminal screen and vision detection system

Abstract

The invention provides a calibration method for a visual mark displayed on a terminal screen and a vision detection system. The calibration method comprises the steps: firstly generating a reference line segment of a specified pixel on the terminal screen, and then performing adjustment and calibration of increasing and decreasing pixels one by one on the reference line segment displayed on the screen by using a real object measuring scale until the display length of the reference line segment reaches a specific size of the mark of the measuring scale, and then substituting the pixel adjustment ratio into a conversion formula of the size of the visual mark for conversion, so that the accurate size of the visual mark of the terminal screen is obtained. According to the calibration method, accurate screen density of the terminal screen is not needed, and the method is not influenced by factors such as a terminal screen manufacturing process. Calculation is accurate, and implementation is convenient. The vision detection system applying the method can ensure that the size of the visual mark seen by the vision detection system during vision detection is consistent with the size of the visual mark seen by other users on respective terminal screens, thereby effectively ensuring that the vision results detected by the vision detection system on different terminals have consistent comparability.

Description

technical field [0001] The invention relates to an optotype calibration method and a vision detection system, in particular to a method for calibrating the size of an optotype when a terminal screen displays an optotype and a vision detection system using the method, belonging to the technical field of vision detection. Background technique [0002] The conventional visual inspection method is to use a fixed standard eye chart for testing. During the test, the subject needs to stand at a certain distance from the eye chart. Feedback the opening direction of the visual mark seen to the tester, and then compare and judge by the tester, and finally obtain the visual acuity value of the testee. In this method, the visual mark arrangement of the eye chart used is fixed, and it is easy for the subject to cheat by memorizing temporarily, resulting in inaccurate test results. Moreover, the eye chart is mostly of light box type or projection type, which is inconvenient to carry. [...

AI Technical Summary

Problems solved by technology

However, in the actual application process, we found that this method still has certain defects. For example, it is not easy to directly obtain the nominal screen density of some terminal screens, and some terminal screens are affected by many factors such as the manufacturing process. There is a certain error between the display size of the visual target directly calculated by the nominal screen density and the theoretical calculation formula and the actual measured physical size, so the size of the visual target displayed on different terminal screens is still not completely consistent

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