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Three-dimensional measurement method and system based on single grating projection

A technology of three-dimensional measurement and grating projection, which is applied in the field of three-dimensional measurement and can solve the problems of complex process and long time consumption.

Active Publication Date: 2017-11-17
SHENZHEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The unwrapping methods currently used, such as the flood method and the quality map guidance method, etc., are relatively complicated and time-consuming, and require two fringe images to obtain the absolute phase.

Method used

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  • Three-dimensional measurement method and system based on single grating projection
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  • Three-dimensional measurement method and system based on single grating projection

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Embodiment 2

[0101] Based on Embodiment 2 of the present invention, a three-dimensional measurement system based on a single grating projection includes:

[0102] The grating module is used to defocus and project the physical grating onto the object to be tested to form a sinusoidal fringe pattern, and collect the deformed fringe pattern of the object to be tested;

[0103] Processing module, for utilizing S transformation method to process deformed fringe pattern to obtain principal value phase φ (x, y);

[0104] Also used for unwrapping based on the dewrapping method to obtain the absolute phase

[0105] The measurement module is used to calibrate the three-dimensional measurement system based on telecentric imaging to establish an imaging model and calculate the three-dimensional coordinate information of the measured object.

[0106] Based on the system described in Embodiment 2 of the present invention, the steps of utilizing the S-transformation method to process the deformed frin...

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PUM

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Abstract

The invention discloses a three-dimensional measurement method and system based on single grating projection. The three-dimensional measurement method comprises the steps that a physical grating is projected to an object to be tested in an out-of-focus manner so as to form a sinusoidal fringe pattern, and a deformed fringe pattern of the object to be tested is collected; the deformed fringe pattern is processed by using an S-transform method to obtain the principal value phase Phi(x, y); unwrapping is performed based on a wrapping elimination method to obtain the absolute phase phi(x, y), and a three-dimensional measurement system for telecentric imaging is calibrated so as to build an imaging model, and three-dimensional coordinate information of the tested object is calculated. The three-dimensional measurement system is used for executing the method. The three-dimensional measurement method is based on the single fringe pattern, zero padding is performed on both ends of the principal value phase after the principal value phase is obtained according to the S-transform method so as to acquire up-sampling in the frequency domain, the frequency spectrum of the phase is shifted to the original position according to frequency shift characteristics of Fourier transform, a phase component of carriers is eliminated, the height-phase mapping relationship is fitted by adopting the telecentric imaging model, the three-dimensional measurement system is calibrated, the three-dimensional coordinate information of the tested object is obtained, the steps are simple, and the measurement speed is higher.

Description

technical field [0001] The invention relates to a three-dimensional measurement method and system based on single grating projection, belonging to the field of three-dimensional measurement. Background technique [0002] In 1983, Takeda et al proposed a three-dimensional surface shape measurement method based on grating projection - Fourier transform profilometry (FTP). Fourier transform profilometry is to project grating stripes on the surface of the object to obtain the deformed grating modulated by the height of the object, and use a specific algorithm to perform Fourier transform, filter, Fourier inverse transform and unwrapping on the deformed fringe image. The phase is extracted, and then the three-dimensional information of the object is obtained by calibrating the measurement system. [0003] In recent years, S-transform has been applied to the phase demodulation process of grating projection in optical three-dimensional surface shape measurement. Compared with FTP,...

Claims

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Application Information

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IPC IPC(8): G01B11/25
CPCG01B11/254
Inventor 田劲东吴建梅李东田勇
Owner SHENZHEN UNIV
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