Unwrapped phase error detection and correction method based on fringe series inaccuracy

Abstract

The invention discloses an unwarping phase error detection and correction method based on the uncertainty of a fringe order. The method defined a new parameter, the uncertainty of the fringe order, used for achieving quick and accurate edge detection on a phase diagram, and thus unwrapping phase error correction is performed. The provided method comprises the main steps of synthesizing different frequency phases in multifrequency phase unwarping, and computing the uncertainty of the fringe order to serve as a medium for detecting the edge of the phase diagram; based on spatial distribution characteristics of the uncertainty of fringe order, marking a phase diagram edge criterion, building a phase diagram edge point-by-point detection scheme accordingly, and thus achieving edge detection ofthe unwarping phase diagram; performing unwarping phase error correction on the detected edge of the phase diagram and an area surrounded by the edge, and thus acquiring correct phase distribution. According to the method disclosed by the invention, detection process and correction process of an unwarping phase error are separated, so that the efficiency of performing error correction on the phase of a discontinuous surface is significantly improved under the premise of ensuring robustness of unwarping phase error correction.

Description

technical field [0001] The invention belongs to the technical field of optical three-dimensional measurement, in particular to an unwrapping phase error detection and correction method based on the inaccuracy of fringe series. Background technique [0002] Fringe projection profilometry is a three-dimensional measurement method with increasing demand, and has broad application prospects in product quality inspection, reverse engineering and other fields. Phase is the core parameter for 3D reconstruction by fringe projection profilometry, and its accuracy directly determines the accuracy of 3D measurement. The phase is obtained from the sampling fringe pattern through two processing steps of phase demodulation and phase unwrapping, and its accuracy is determined by the accuracy of the demodulated phase and the accuracy of the unwrapped phase. The multi-frequency method is a typical phase unwrapping method, which has the advantages of point-by-point processing, fast speed, an...

AI Technical Summary

Problems solved by technology

The method proposed by Feng Shijie et al. cannot detect large areas of points with unwrapped phase errors. In addition, there may be misjudgment of some mis-smoothed points, and the detected error points are not corrected.

The method proposed by Yi Ding et al. is also unable to detect large areas of points with unwrapped phase errors, and when there is a large surface discontinuity across the field of view, misjudgment of the phase of nearby areas may occur

The method proposed by Dong-ukKam et al. has similar shortcomings to the method proposed by Feng Shijie et al. In addition, it needs to calculate the mean square error of the phase, the second norm and other parameters point by point in the specific use process, and it is difficult to quickly correct the phase error.

The method proposed by Zhang Chunwei et al. does not separate the phase error detection and correction process, so it cannot perform fast error correction for phases with discontinuous regions

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