Regional Gamma precorrection phase error compensation method in large view field structured light vision measurement

A visual measurement, phase error technology, applied in the field of phase error compensation, adaptive subregional Gamma pre-correction phase error compensation
CN105403172AActive Publication Date: 2016-03-16HUAQIAO UNIVERSITY
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Patent Information

Authority / Receiving Office
CN Β· China
Current Assignee / Owner
HUAQIAO UNIVERSITY
Publication Date
2016-03-16

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Abstract

The invention discloses a phase error compensation method for large view field adaptive regional Gamma precorrection. A standard N-step phase shift sinusoidal grating image is projected through a projector on the surface of a measured object; a camera is adopted to acquire the projected image; through carrying out phase demodulation on the phase shift image, the phase value of each pixel point is calculated and acquired, and thus, the three-dimensional surface information of the measured object is obtained reversely. In a large view field condition, Gamma values have large differences in a measurement range, residual errors exist when a single Gamma value is adopted for precorrection compensation, a least square fitting method is adopted to acquire the actual Gamma value at each pixel point position, the allowable maximal Gamma value change range deltaG is set to be a threshold according to the Gamma value distribution condition, the measurement region is divided, and thus, multiple Gamma values are adopted to carry out pre-coding correction on the ideal phase shift sinusoidal grating image, and phase errors caused by Gamma nonlinear distortion can be compensated.
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Description

technical field

[0001] The invention relates to a phase error compensation technology in structured light vision measurement based on a phase shift method, in particular to a phase error compensation method for self-adaptive sub-area Gamma pre-correction in the case of a large field of view, and belongs to the technical field of machine vision. Background technique

[0002] A structured light vision measurement method based on phase shift technology, including a monocular structured light vision measurement method and a binocular structured light vision measurement method. No matter what method is used to obtain the three-dimensional data of the measured object, it is necessary to extract the phase, and the accuracy of phase extraction directly affects the final measurement accuracy of the system. In the measurement system, the Gamma nonlinear distortion of the camera and projector is one of the main factors affecting the high-precision phase extraction. Gamma nonlinear dis...

Claims

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