Stacked-gate sine stripe projection phase shifting grating

Abstract

The invention relates to a stacked-gate sine stripe projection phase shifting grating, belonging to an optical three-dimensional measurement technology. A first cross-shaped calibration, a first rectangular calibration and rectangular gratings A, B and C with different periods are arranged on a first grating glass substrate of a coating, a second cross-shaped calibration, a second rectangular calibration and rectangular gratings A', B' and C' with different periods are arranged on a second grating glass substrate of the coating, the first grating glass substrate of the coating and the second glass substrate of the coating are laminated into a whole, the first cross-shaped calibration and the second cross-shaped calibration are aligned and positioned, the first rectangular calibration and the second rectangular calibration are aligned and positioned, the rectangular gratings A, B and C are respectively laminated with the rectangular gratings A', B' and C', the grating stripe directions of all the rectangular gratings are mutually parallel, and the grating period is 40-100wires/mm. By applying the grating provided by the invention, structured light projection light intensity stripe sine distribution is realized, and the grating provided by the invention has the characteristics of simple structure, easiness in grating engraving, low processing cost, high contrast ratio, high measurement accuracy and good stability.

Description

technical field [0001] The invention belongs to the technical field of optical three-dimensional measurement, and mainly relates to a sinusoidal fringe projection phase shift grating. Background technique [0002] At present, the core technology that affects the accuracy of optical three-dimensional measurement is the sinusoidal fringe projection grating. The ideal production of the sinusoidal fringe projection grating needs to be achieved by marking the thickness or width gradient on the optical glass base coating. At present, this ideal sinusoidal transmission grating cannot be engraved in China, and a rectangular grating is generally used instead. However, due to the limitation of the modulation transfer function of the imaging system, this rectangular grating will produce phase mismatch, and it is difficult to make the structured light projection stripes of the grating a continuous and smooth sinusoidal light intensity distribution curve, which will cause distortion in t...

AI Technical Summary

Problems solved by technology

At present, this ideal sinusoidal transmission grating cannot be engraved in China, and a rectangular grating is generally used instead.

However, due to the limitation of the modulation transfer function of the imaging system, this rectangular grating will produce phase mismatch, and it is difficult to make the structured light projection stripes of the grating a continuous and smooth sinusoidal light intensity distribution curve, which will cause distortion in the optical three-dimensional shape measurement. Reduced measurement accuracy of the 3D measurement system

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