A continuous scanning structured light three-dimensional surface shape vertical measurement method

Abstract

The invention relates to a method for vertically measuring three-dimensional surface shapes of structured light in a continuous scanning mode. While the image plane of the structured light projection device continuously scans the measured object along the vertical direction, N frames (N≧3) N-step phase-shifted sinusoidal gratings are sequentially imaged on the measured object, and the CCD camera passes through a semi-transparent The mirror acquires the sinusoidal grating image modulated by the height of the object synchronously from the same direction. Perform Fourier transform processing on the collected picture set pixel by pixel along the time axis or use N-step phase shift algorithm for pictures of continuous N frames (N≧3) phase-shifted sinusoidal grating images, so as to obtain the position of the sinusoidal grating image on the surface of the object Modulation distribution. The three-dimensional surface shape of the object is reconstructed by using the corresponding relationship between the modulation value obtained in advance and the height. The invention not only has the characteristics of vertical measurement, but also has the characteristics of high-precision measurement of three-dimensional surface shape.

Description

technical field [0001] The invention relates to a structured light projection optical surface shape measurement technology, in particular to a three-dimensional surface shape vertical measurement method in which the projection direction and the fringe pattern detection direction are coaxial. 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 (SPD for short). , P...

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Problems solved by technology

[0003] The present invention aims at the defects in the existing modulation degree measurement profilometry: the accuracy of the Fourier transform method is not high and the number of pictures required to be collected by the phase shift algorithm is large and the measurement speed is slow, and a new vertical measurement method is proposed method

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