A method and device for three-dimensional measurement of structured light based on defocus unwrapping

Abstract

The invention relates to the technical field of optical three-dimensional measurement, and discloses a structured light three-dimensional measurement method and device based on defocus unwrapping. The invention proposes the concept of the defocus phase function based on the mathematical analysis of the defocus degree and the phase, and the function is used to represent the functional relationship between the defocus degree and the phase. The present invention projects binary fringes with different fringe widths on the object to be measured, and takes pictures to collect corresponding fringe images, calculates the wrapping phase of the fringe images, and then calculates the defocus according to the modulation degree of the binary fringes with different fringe widths. The obtained defocus is substituted into the calibrated defocus phase function to obtain a reference phase, which is unwrapped based on the reference phase to obtain the absolute phase for reconstructing the 3D point cloud. Different from the multi-frequency heterodyne method which depends on the phase accuracy, the present invention is not affected by the magnitude of the phase error, and can achieve high-precision three-dimensional measurement in the scenario where the phase error increases due to a large depth change.

Description

technical field [0001] The invention relates to the technical field of optical three-dimensional measurement, in particular to a structured light three-dimensional measurement method and device based on defocus unwrapping. Background technique [0002] Based on the rapid development of projection and imaging technology, the structured light 3D measurement method has the characteristics of high speed, high precision and wide application range, and is one of the widely used non-contact 3D measurement methods. Most of the current structured light 3D measurement methods are based on binary fringe defocus projection technology. [0003] The principle of the binary fringe defocus projection technology is to use the defocus effect to blur the binary fringes into standard sinusoidal fringes. Excessive or insufficient defocusing of binary fringes will lead to an increase in the wrapping phase error, and the accuracy of the phase unwrapping is based on the accuracy of the wrapping ph...

AI Technical Summary

Problems solved by technology

[0004] The invention provides a structured light three-dimensional measurement method and device based on defocus unwrapping, which solves the technical problem that the existing phase unwrapping method is difficult to achieve high-precision three-dimensional measurement because it is easily affected by the wrapping phase error

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