Self-correcting method for optical grating based on linear phase position

Abstract

The invention discloses a grating self-tuning method based on the straight line phase in the three dimensional sweeping system, which relates to the reversion project, obtains four phase-shifts charts with the phase-shift method, then, carries on the straight line phase transition to the obtained four phase-shifts chart, carries on the two rides straight line fitting to the straight line phase obtain the fitting straight line phase, adjust the phase spot of deviate fitting straight line phase on the fitting straight line phase and obtain the adjustment phase spot, and then based the adjust phase spot, carry on the inverse transformation with the phase-shift method to obtain the new four phase-shifts chart, compared with the original four phase-shifts chart, obtain the transfer function between the projection diffraction grating and the gathering grating, and take the transfer function as the adjustment optimization function, adjust the computer production diffraction grating, realized the self-tuning of the grating. The method effectively improved the projection grating profile sine and the precise phase-shift, can enhance the grating profile robustness, also can increase the phase-shift precision, and then enhance the system measuring accuracy.

Description

technical field [0001] The invention belongs to the technical field of three-dimensional information reconstruction, and mainly relates to a method for self-correction of projection grating through linear phase correction by combining Gray code and phase shift method in a three-dimensional scanning system in reverse engineering, in particular to a method based on linear phase Grating self-calibration method. Background technique [0002] When the grating is projected onto the surface of the object, the phase of the periodic grating is modulated by the height profile of the object surface, forming a deformed grating, which carries the three-dimensional information of the object. Accurately obtaining the phase information modulated by the height of the object and performing phase unwrapping is the core of the fringe image automatic analysis technology, which plays a key role in obtaining the three-dimensional information of the object. The sinusoidality and precise phase shif...

AI Technical Summary

Problems solved by technology

The triangulation method has a clear principle and good real-time performance, but the density of the measurement points is not high. If thinner fringes are used for projection, it will be more difficult to find fringes, so we use the phase method for processing

The basic requirement of grating projection three-dimensional measurement is that the projected grating has a certain distribution (such as standard sinusoidal distribution), but in fact, due to the existence of various errors and disturbance factors, the grating stripes collected by CCD are not standard sinusoidal distribution, making the grating waveform Imprecision and non-sinusoidal phase shift become important factors affecting measurement accuracy

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