Method for measuring modulation transfer function value of measurement lens

Abstract

The invention discloses a method for measuring the modulation transfer function value of a measurement lens, which comprises: acquiring continuous modulation transfer function value for the lens to be tested to image a plurality of test patterns at a continuous image distance by using a mobile image sensor, and acquiring the continuous relationship curve of the object distance of the lens to be tested and the modulation transfer function value according to a Gauss formula; rotating the lens to be tested around the optical axis of the lens at the same angle for many times to a plurality of test positions to image the test patterns corresponding to the positions respectively, and acquiring the modulation transfer function values of the images; obtaining a plurality of object distance values corresponding to the modulation transfer function values obtained at the plurality of test positions from the continuous relationship curve, and adjusting a bearing table according to the plurality of object distances to make the distances between the bearing table and a test plate at the positions of the plurality of test patterns equal; and moving the bearing table along the optical axis of the lens to be tested and relative to the test plate for testing the accurate modulation transfer function value of the lens to be tested.

Description

technical field [0001] The invention relates to the technical field of lens detection, in particular to a method for measuring the modulation transfer function value of a lens. Background technique [0002] The image quality of imaging objects such as digital cameras, video cameras and mobile phone cameras mainly depends on the imaging quality of the lens, and the monitoring of the image quality of the lens lies in the testing process of the lens. Modulation Transfer Function (MTF) is an important parameter for analyzing the resolution and contrast reproduction ability of a lens, and comprehensively evaluating the sharpness, contrast and resolution of a lens. See literature: A simple method for determining the modulationtransfer function indigital radiography; Fujita, H., Tsai, D-Y., Itoh, T., Department of Electronic & Computer Engineering, England, Gifu University; Medical imaging, IEEE transactions on; pages 34 ~39, Volume 11, Issue 1, March.1992. [0003] A commonly us...

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Problems solved by technology

[0004] However, during the test, the carrying platform may be inclined relative to the test board or the image sensor, causing the optical axis of the lens to be tested carried on it to be not perpendicular to the

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