A three-dimensional measurement method for projecting non-uniform fringes in non-fully constrained systems

Abstract

The invention discloses a three-dimensional measurement method for projecting non-uniform stripes in a non-complete constraint system. The three-dimensional measurement method uses a computer to obtain multiple phase-shift cosine striped image and auxiliary images and uses a projector to project the striped images to a reference plane, an object to be detected or planes of various heights; a camera synchronously shoots transformative striped images and the auxiliary images on the reference image, the object to be detected and the planes of various heights; a computer obtains a truncation phase of a phase shift strip and performs phase unwrapping; and then three-dimensional feature data of the object is obtained. The three-dimensional measurement method utilizes a continuous absolute phase to directly solve and obtain the height of the object, does not need to solve a phase difference, improves measurement efficiency and reduces an error introduced while solving the phase difference. The three-dimensional measurement method adopts the non-complete constraint system, has not strict requirements for installation of a measurement system, relieves a constraint that a connection line between a camera optic center and a projector optic center is parallel to the reference plane, and relieve a constraint a camera optic axis is intersected with a projector optic axis at one point on the reference plane.

Description

technical field [0001] The invention relates to the field of three-dimensional optical measurement, in particular to a three-dimensional measurement method for projecting non-uniform fringes in a non-completely constrained system. Background technique [0002] In the field of machine vision, the three-dimensional structured light measurement method has been widely used in reverse engineering, cultural relics protection, medicine and other fields due to its non-contact measurement, fast speed, and high precision. Among them, the four-step phase-shift surface structured light measurement method, due to A measurement can obtain more data and has been widely studied. In the traditional surface structured light measurement technology, a system model with strict constraints on the installation position of the camera and projector is usually used, and the measurement form of vertical shooting and oblique projection is adopted. [0003] At present, the commonly used measurement syst...

AI Technical Summary

Problems solved by technology

Due to the strong anti-interference ability of binary coded black and white stripes to various noises, the accuracy of unwrapped phase is higher. In addition, compared with other binary coded phase unraveling methods, this method only needs three auxiliary fringe images to achieve 2 6 This encoding combination shortens the measurement time while ensuring the measurement accuracy, but the binary encoding method generally has the problem of low accuracy in the selection of the auxiliary fringe binarization threshold during decoding.

In addition, the distribution of truncated phase boundaries of non-uniform fringes is irregular, making the binary coding for non-uniform fringe boundaries very difficult

Images