Dynamic target modulation transfer function measurement method

Abstract

A measuring method for dynamic object modulation transfer function belongs to the test field of optical properties. The invention aims to provide a measuring method for dynamic object modulation transfer function that can not only remove background vagabond ray and dark current of an image sensor, but also remove nonideal target size and the effect on a measuring result by the diffraction and aberration defect of an optical system. The method first respectively records an interference image, a still image and a dynamic image through imaging under the condition of closing and lightening a point light source, keeping the light source still and moving the light source, respectively uses the still image, the dynamic image and the interference image to do subtraction and obtain an anti-interference still image and an anti-interference dynamic image, extracts and modifies line spread function therein to obtain modified static and dynamic object line spread functions and obtains initial static and dynamic object modulation transfer functions through Fourier transformation. And finally, the method uses the initial dynamic object modulation transfer function to be divided by the initial static object modulation transfer function, thus obtaining the final measuring result of the dynamic object modulation transfer function.

Description

technical field [0001] The invention relates to a measurement method of a modulation transfer function in the field of optical property testing, in particular to a measurement method of a dynamic target modulation transfer function. Background technique [0002] The modulation transfer function of a dynamic target is an important parameter to quantitatively describe the degree of image quality degradation caused by target motion during the imaging process of a time-lapse imaging system for a dynamic target. Measuring the modulation transfer function of the dynamic target and obtaining the transfer function curve can not only obtain the degree of image quality degradation, but also analyze the cause of image quality degradation, and provide a theoretical basis for motion blurred image restoration. [0003] In 1992, SPIE Volume 1971 "Real-Time Numerical Calculation of Optical Transfer Function for Image Motion and Vibration. Part 1: Experiment Verification" introduced a point ...

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Problems solved by technology

This method considers that the size of the point light source is negligible, and by selecting a small interval, the dark current of the image sensor outside the interval and the noise introduced by the background light can be filtered out, but its disadvantages are: ① It does not consider The influence of diffraction and aberration of the lens on the measurement results of the transfer function during the imaging process; ② did not take into account the influence of the dark current of the image sensor and the background light on the measurement results of the transfer function within the selected range; ③ no Explain the effect of the target on the transfer function measurement results when the size of the point source is not negligible

But its shortcoming is that it does not take into account the background light and the dark current of the image sensor introduced to the noise of the static target image and the dynamic target image, and finally makes the measurement result of the dynamic target modulation transfer function glitchy.

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