Continuous-scanning structured light three-dimensional surface shape perpendicular measuring method

Abstract

The invention provides a structured light three-dimensional surface shape perpendicular measuring method using a continuous scanning mode. When a measured objected is continuously scanned by an image surface of a structured light projector in the perpendicular direction, N frames (N>=3) N-step phase shift sinusoidal gratings are sequentially and cyclically imaged on the measured objected, a CCD camera synchronously obtains sinusoidal grating images subjected to object height modulation through a semi-transparent semi-reflective mirror in the same direction. Fourier transformation processing is conducted on the collected image set pixel by pixel along the time axis or the N-step phase shift algorithm is applied to continuous N frames (N>=3) phase shift sinusoidal grating images, so that distribution of modulation degrees of the sinusoidal grating images on the surface of the object is obtained. A three-dimensional surface shape of the object is rebuilt through a corresponding relation, which is obtained in advance through calibration, between the modulation degrees and the height. The continuous-scanning structured light three-dimensional surface shape perpendicular measuring method has the advantages of perpendicular measurement and three-dimensional surface shape high-precision measurement.

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 (Spatial Phase Detect...

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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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