Object surface micro-scale measurement method based on pixel grating and computer vision

Abstract

The invention discloses an object surface micro-scale measurement method based on a pixel grating and computer vision. The method comprises the following steps of: projecting a single-pixel wide-stripe grating pattern by using a projector, and carrying out grating test until a camera can shoot clear stripe pictures; calibrating the camera and the projector; calculating calibration results; carrying out grating projection to obtain a stripe picture; then carrying out image enhancement, denoising, image matting, center line extraction and specific point solving, and calculating space coordinatesof one point on an object by using a space geometry method; and finally, integrating all space coordinates to form an object surface three-dimensional point set, and completing specific surface concave-convex measurement requirements by using the three-dimensional point set. The invention provides a new grating projection image processing and calculating scheme, the research content of grating projection three-dimensional detection is expanded, and the width of each projected stripe can be remarkably reduced by using the single-pixel wide stripes, so that the detection accuracy is greatly improved, and the micro-scale measurement of the surface of the object is realized.

Description

technical field [0001] The invention relates to the technical field of grating projection three-dimensional imaging, in particular to a micro-scale measurement method of object surface based on pixel grating and computer vision. Background technique [0002] The 3D reconstruction technology based on digital grating projected structured light is a visual measurement technology developed in recent years. Grating projection measurement technology has the advantages of high scanning speed, high precision, non-contact, etc., and is easy to apply in high automation. At present, grating projection three-dimensional measurement technology is widely used in many fields such as three-dimensional measurement, computer-aided design and reverse engineering, especially in the measurement occasions requiring non-contact, high precision and high efficiency. Among many optical three-dimensional measurement technologies, this active measurement method has gradually become one of the main tec...

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Problems solved by technology

The larger the resolution, the smaller the projection area, and the fewer pixels occupied by the stripes, the smaller the width of the grating and the higher the measurement accuracy. Therefore, reducing the number of pixels occupied by the stripes, at least 1 pixel and 1 stripe, can greatly improve the measurement accuracy. The research objects in the existing papers and patents on grating projection 3D imaging are multi-pixel stripes. According to the common projector parameters on the market, the accuracy between 0.1 and 1mm cannot be achieved, and only single-pixel stripes can be used.

However, the existing calculation method for 3D reconstruction of grating projection is also based on multi-pixel fringes to form a sinusoidal grating and then perform dephasing calculations. When single-pixel fringes are used, the sinusoidality of projected fringes cannot be guaranteed, and this calculation method is invalid. Therefore, for single-pixel grating fringes Projection also requires the study of a new set of calculation methods

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