16-step dual-frequency grating phase shift profilometry capable of absolute phase unwrapping

A dual-frequency grating and phase technology, applied in the field of optical three-dimensional sensing, can solve the problems that the measurement accuracy and measurement range cannot be guaranteed at the same time, and achieve the effects of suppressing the accumulation of error diffusion, strong adaptability, and high measurement accuracy

Inactive Publication Date: 2010-02-24
SICHUAN UNIV
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Problems solved by technology

[0003] The purpose of the present invention is to address the defect that the traditional phase measurement profilometry cannot guarantee the measurement accuracy and measurement ra

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  • 16-step dual-frequency grating phase shift profilometry capable of absolute phase unwrapping
  • 16-step dual-frequency grating phase shift profilometry capable of absolute phase unwrapping
  • 16-step dual-frequency grating phase shift profilometry capable of absolute phase unwrapping

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Embodiment Construction

[0015] The present invention will be described in further detail below in conjunction with the accompanying drawings and working principles.

[0016] The optical path of real-time three-dimensional surface measurement with dual-frequency grating is similar to that of traditional phase measurement profilometry. figure 1 is the projection light path of the PMP method, P 1 and P 2 are the entrance pupil and exit pupil of the projection system, I 2 and I 1 are the entrance and exit pupils of the imaging system. The imaging optical axis is perpendicular to the reference plane, and the included angle with the projection optical axis is θ, they intersect at point O on the reference plane, d is the distance between the optical center of the detector and the optical center of the projection device, l is the detector light The distance from the center to the reference plane.

[0017] The measurement model using non-integer multiple double-frequency grating projection, the measureme...

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Abstract

The invention provides 16-step dual-frequency grating phase shift profilometry capable of absolute phase unwrapping in the three-dimensional sensor technology. The invention is characterized by usingcomputers to design codes to generate 16 dual-frequency grating patterns, using a digital light projector to image the grating patterns on the surface of an object instantaneously in sequence, using apick-up device to record the deforming fringe pattern of the object, subsequently using the functional relationship between the gratings with two frequencies, using the absolute phase unwrapping method to directly realize phase unwrapping of point to point in the whole field range and having no relation with the path for phase unwrapping, effectively inhibiting accumulative error diffusion, usingphase measuring profilometry to process the deforming fringes, accurately restoring the three-dimensional shape of the object and obtaining such digital information as deformation of the object and the like by further analyzing the data processing results. The method can be used for measurement study of the characteristics of the object surface with the characteristic of diffuse reflection. The method has the advantages of high measurement precision and strong adaptability to the surface topography of the object, etc.

Description

1. Technical field [0001] The invention relates to optical three-dimensional sensing technology, in particular to the three-dimensional surface shape measurement of an object by using a dual-frequency grating based on a phase measurement profilometry method. 2. Technical Background [0002] Three-dimensional surface measurement is of great significance in the fields of machine vision, biomedicine, industrial inspection, rapid prototyping, film and television special effects, and product quality control. Optical three-dimensional sensing technology has been widely researched and applied due to its advantages of non-contact, high precision, large-area measurement, 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 for short). SPD), phase measuring profilometry (Phase Measuring Profilome...

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Application Information

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IPC IPC(8): G01B11/25
Inventor 曹益平何宇航苏显渝向立群陈文静张启灿刘元坤
Owner SICHUAN UNIV
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