Laser linear scanning three-dimensional measurement double liquid knife virtual grid mapping calibrating method and equipment

Abstract

The invnetion discloses a method and set for calibrating the mapping of virtual grid by using double light-knifes in three-dimension measure of laser line scanning. The set includes central processing unit, controller, measuring base stage, translating slide guides, photoelectric measuring head and standard flat plate. There are three slide guides along X, Y, Z, axes, and said measuring head is installed on the lower end of Z-axis. The standard flat plate is on the surface of base stage. The virtual grid builds up the relationship of mapping function between two-dimension imaging space and two-dimension physical space, so as to realize accurate calibration of measuring system. When measuring is carried on, the coordinate values of physical space that is relevant to each imaging point on measuring light-knifes can be measured. With scanning by the photoelectric measuring head going on, the information of three-dimension contour of surface of object measured can be obtained.

Description

1. Technical field [0001] The invention belongs to a method and device for three-dimensional profile measurement, in particular to a laser line scanning three-dimensional measurement double-light knife virtual grid mapping calibration method and device. 2. Background technology [0002] At present, in the laser line scanning three-dimensional contour measurement system, the measurement principle adopted is the triangulation method, that is, the three-dimensional information of each point of the contour of the measured object is determined through the triangular geometric relationship between the exit point, the projection point and the imaging point. . The measurement system generally adopts the method of laser vertical incidence and CCD vertical imaging. In the laser vertical incidence, the linear light source formed by the laser (hereinafter referred to as the light knife) is vertically incident on the base plane where the workpiece to be measured is placed. CCD vertical ...

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Problems solved by technology

[0007] 3) The calibration steps in the two directions of the above two methods are isolated, and the mathematical model used as the premise of calibration is ideal, but the actual situation is much more complicated

[0010] i) The relationship between the standard plane coordinate system and the measurement system coordinate system cannot be accurately determined;

[0011] ii) The manufacturing accuracy of the grid or dot matrix affects the measurement results;

[0012] iii) Once the grid or dot matrix is ​​made, its spacing is fixed, which cannot be adapted to the needs of different occasions;

[0013] iv) The calculation error of grid intersection or point center coordinates is relatively large, etc.

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