Three-dimensional measurement method suitable for bright surface

Abstract

The invention discloses a three-dimensional measurement method suitable for a bright surface. According to images synthesized through uniform-light patterns and coordinate mapping, an optimal projection gray value of each pixel point in a stripe pattern is adaptively adjusted, when the method is used for measuring three-dimensional morphology comprising large-scope reflectivity change, for a bright area with high reflectivity, image saturation can be avoided, for a dark area with low reflectivity, a quite high signal-to-noise ration can be maintained, finally, clear stripe pattern images can be obtained, and the three-dimensional morphology of a measured object can be accurately restored.

Description

technical field [0001] The invention relates to an optical measurement method, in particular to a structured light three-dimensional measurement method. Background technique [0002] The structured light method is an active optical measurement method. Its basic principle is to project a controllable light point, light bar or light surface on the surface of the measured object by a structured light projector, and collect images by an image sensor (such as a camera). Through the geometric relationship of the system, the three-dimensional coordinates of the object are calculated by using the triangulation principle. The structured light measurement method is widely used in product quality inspection, reverse engineering (digitization of complex free-form surfaces), object recognition, 3D map construction, biomedicine and cultural relics protection due to its advantages of non-contact, full-field scanning, high precision, and fast measurement speed field. [0003] However, whe...

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Problems solved by technology

But for the surface of the metal workpiece, the diffusely reflected light is weak and the signal-to-noise ratio is low, which will lead to a significant decrease in measurement accuracy; in addition, adding a polarizer increases the complexity of the hardware system

Some scholars use the method of spraying a thin anti-reflection coating on the surface of the measured object to change the reflection property of the surface into diffuse reflection, so as to facilitate the three-dimensional measurement of structured light; however, the thickness and uniformity of the coating are uncertain. It is easy to cause measurement errors, and spraying and cleaning coatings also reduce measurement efficiency

[0005] In short, there is currently no relatively complete solution for the three-dimensional topography measurement of shiny surfaces.

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