Phase grade self-coding-based optical three-dimensional measurement method

Abstract

The invention discloses a phase grade self-coding-based optical three-dimensional measurement method. In the traditional phase measurement technology, generally additional coding patterns need to be projected to realize three-dimensional profile measurement of an isolated object. The method comprises the following steps of: providing sinusoidal stripes, the digital projection of which has phase grade coding information; constructing a code sequence, the total length of which is equal to the projected stripe period sum, by using the differential value or the slope value of phase distribution as a coding channel and using each stripe period as a coding unit; constructing a code sub sequence by using a plurality of adjacent periods; searching the position of the code sub sequence in the total code sequence to determine the phase grade of the period so as to obtain absolute phase distribution of the object to be measured; and finally, reconstructing a three-dimensional profile of the object to be measured according to the phase height relationship. The method can complete three-dimensional information acquisition of the object without projecting the additional coding patterns, and is particularly suitable for quick three-dimensional profile measurement of the isolated object.

Description

technical field [0001] The invention relates to optical three-dimensional sensing technology, in particular to three-dimensional surface shape measurement of spatially isolated objects based on phase measurement profilometry. Background technique [0002] Three-dimensional object surface profile measurement, that is, three-dimensional surface shape measurement, is of great significance in the fields of machine vision, biomedicine, industrial inspection, rapid prototyping, film and television special effects, product quality control and other fields. Optical three-dimensional sensing technology has been greatly developed due to its advantages of non-contact, high precision, and easy automatic control. Existing optical three-dimensional sensing methods mainly include: triangulation, Moiré Topography (MT for short), Fourier Transform Profilometry (FTP for short), and spatial phase detection (Spatial Phase Detection). , referred to as SPD), Phase Measuring Profilometry (Phase M...

AI Technical Summary

Problems solved by technology

Phase measurement profilometry needs to reconstruct the three-dimensional surface shape from multiple frames of phase-shifted fringe patterns, which has high accuracy. However, in the traditional phase measurement technology, phase unwrapping is a difficult problem when measuring discontinuous objects. At this time, it usually needs Projecting additional coding patterns, such as time phase unwrapping or sinusoidal fringe projection combined with Gray code methods, etc., but these methods are not suitable for fast 3D measurement of discrete object scenes due to the projection of additional coding patterns

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