Image encoding and decoding method in surface structured light measurement system

Abstract

The invention belongs to the field of optical measurement, and discloses an image encoding and decoding method in a surface structured light measurement system. The method comprises the following steps: (a) for a surface structured light measurement system, setting each parameter value of a projector, establishing a relational expression of winding phase shift coordinates and phase shift of each point in an image projected by the projector, and projecting by the projector in combination with the set parameter values and the relational expression so as to realize image encoding and obtain a plurality of phase shift images; (b) shooting the phase shift images by a camera to obtain a plurality of shot images, and establishing a relational expression to calculate and obtain a winding phase shift and a winding phase corresponding to each point in the shot images; and (c) obtaining a pixel coordinate of each point by utilizing the winding phase shift and the winding phase of each point in the shot image so as to realize decoding of the image. According to the invention, the propagation of the phase shift error to the phase inversion error is significantly reduced, and the phase shift decoding precision of the surface structured light measurement system is improved, so that the three-dimensional measurement precision is improved.

Description

technical field [0001] The invention belongs to the field of optical measurement, and more specifically relates to an image encoding and decoding method in a surface structured light measurement system. Background technique [0002] For the study of phase measurement profilometry, the literature "Zhang, X., Li, C., Zhang, Q., and Tu, D, Optics & Laser Technology, 108, 69-80" studies the phase measurement profilometry, and the literature "Li, C., Zhang, X., and Tu, D, Optical Engineering, 57(3), 034103" studied the phase measurement deviation instrument and so on. Optical metrology methods are playing an increasingly important role in modern manufacturing. Among them, phase shifting technology is a very key technology, it is a bridge connecting the measured object and sensor information. As the basis of error propagation, phase inversion accuracy directly affects the measurement accuracy of the system. Traditional phase encoding methods, such as "Zhang, X., Zhu, L., Tu, D....

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Problems solved by technology

The effects of these methods on reducing the phase retrieval error are not obvious, because the light intensity error is only suppressed by one layer of suppressor to the phase retrieval error

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