Optical axis and object plane perpendicularity detection method based on geometric error correction technology

Abstract

The invention discloses an optical axis and object plane verticality detection method based on the geometric error correction technology, comprising the steps of: allowing a camera and an XY plane to move relatively, and allowing the camera to arrive at a first imaging point from a zero point along any coordinate axis; at the first imaging point, changing an object distance, collecting an image, and selecting a definition evaluation function to calculate an image definition function value until an image definition function reaches a greatest value; adjusting the camera to the zero point; allowing the camera and the XY plane to move relatively, and allowing the camera to arrive at a second imaging point from a zero point along a same axis of motion; at the second imaging point, changing an object distance, collecting an image, and selecting a definition evaluation function to calculate an image definition function value until an image definition function reaches a greatest value; and calculating optical axis and object plane verticality deviation. The invention realizes measuring system optical axis and object plane verticality deviation detection according to position relationships of different imaging points, the object distance difference when the image definition function value at each imaging point reaches a greatest value and the geometric error correction technology.

Description

technical field [0001] The invention relates to the field of visual measurement, in particular to a method for detecting the perpendicularity between an optical axis and an object plane based on geometric error correction technology and image clarity. Background technique [0002] In the image measurement system using the principle of CCD imaging, the verticality deviation between the camera optical axis and the measurement surface will cause a certain measurement error. In a high-precision measurement system, a small deviation angle may have a serious impact on the final measurement result. Influence. Therefore, it is necessary to accurately measure the deviation angle of the perpendicularity between the optical axis and the object surface, and then adjust or compensate the error to ensure the accuracy of the measurement results. [0003] At present, there are roughly the following methods for detecting verticality: 1. Use a square ruler with a feeler gauge to measure the ...

AI Technical Summary

Problems solved by technology

The former can collect images of standard gauge blocks, and compare the results obtained by visual measurement with the true value of the gauge blocks. Since the obtained image is deformed into a secondary error, the detection accuracy is low

The latter can collect an image of a standard circle, and detect the perpendicularity deviation angle between the optical axis and the object surface by comparing the two diameters perpendicular to each other in the image. Since it involves curve fitting and the fitting accuracy cannot be evaluated, the detection accuracy of this method is also difficult to obtain. ensure

3. Use the autocollimator to measure the vertical deviation angle between the optical axis and the object surface. This method cannot guarantee the parallelism between the light emitted by the autocollimator and the optical axis, so it is difficult to guarantee the detection accuracy.

However, in a visual measurement system with a large stroke and a small field of view, the size of the field of view limits the detection accuracy of this method

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