Defocusing projection grating measurement method based on Sierra Lite dithering algorithm

A technique of grating measurement and dithering algorithm, which can be applied to measurement devices, optical devices, instruments, etc., and can solve problems such as reducing the sine of defocused gratings and measuring quality.

Inactive Publication Date: 2014-02-05
SOUTHEAST UNIV
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Problems solved by technology

[0011] Aiming at the problem that high-order harmonics generated by projector defocusing technology reduce the sinusoidality

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  • Defocusing projection grating measurement method based on Sierra Lite dithering algorithm
  • Defocusing projection grating measurement method based on Sierra Lite dithering algorithm
  • Defocusing projection grating measurement method based on Sierra Lite dithering algorithm

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Embodiment Construction

[0113] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. Under the Windows operating system, MATLAB is selected as the programming tool to process the sinusoidal grating generated by the computer and the deformed grating collected by the CCD camera. In this example, plastic foam is used as the measured object, and a relatively accurate absolute phase distribution containing three-dimensional information is finally obtained.

[0114] figure 1 It is a flowchart of the whole process of the present invention.

[0115] figure 2 It is the specific process flow chart of Sierra Lite dithering algorithm to generate dithered raster.

[0116] Aiming at the problem that the high-order harmonic generated by the defocusing technology of the projector reduces the sinusoidality and measurement quality of the defocusing grating, the invention provides a solution in the aspect of binary grating generation. The i...

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Abstract

A defocusing projection grating measurement method based on a Sierra Lite dithering algorithm mainly aims to generate a two-value dithering grating through the Sierra Lite dithering algorithm, improve the sine performance of the grating after defocusing and then improve the quality of a phase position. The defocusing projection grating measurement method includes the implement steps of generating a sine grating by a computer, calculating dithering output starting from the pixel at the top left corner of an image of the grating, calculating a quantization error of the pixel according to a gray value of the dithering output, selecting an S-shaped scanning direction and a corresponding kernel function coefficient to diffuse the error according to the fact that whether the pixel is in an odd-numbered line or an even-numbered line or not, overlapping the error to a corresponding next pixel until the image of the whole grating is processed completely, obtaining a needed measured grating by defocusing and projecting the finally obtained dithering grating through a projector, obtaining a principal value phase position through a classic four-step phase shift method, unfolding the principal value phase position to obtain an absolute phase position, and finally obtaining three-dimensional information of a measured object according to a conversion formula between the phase position and height.

Description

technical field [0001] The invention belongs to the field of three-dimensional information reconstruction, and in particular relates to a defocus projection grating measurement method based on a Sierra Lite dithering algorithm. Background technique [0002] Optical three-dimensional measurement technology can accurately obtain three-dimensional surface data of objects, which can be used for three-dimensional model reconstruction, object surface profile measurement, detection of size and shape parameters in industrial environments, etc., so it is used in virtual reality, projection special effects, medical plastic surgery and Beauty, appearance design of industrial products, art sculpture and cultural relics protection and other fields have broad application prospects. [0003] The grating projection method is an important three-dimensional measurement technology. By projecting a sinusoidal grating to the surface of the object, the height information of the object is modulate...

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Application Information

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IPC IPC(8): G01B11/25
Inventor 达飞鹏吕江昭饶立安东刘超常朋朋李燕春
Owner SOUTHEAST UNIV
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