Plane structured light and light pen-based precise three-dimensional measurement method for complex part

Abstract

The invention belongs to the field of precise measurement and discloses a plane structured light and light pen-based precise three-dimensional measurement method for a complex part and a system for implementing the method. According to the method, the complex shape of the surface of the part is measured by a plane structured light three-dimensional measurement technology, the characteristic dimension such as an inner wall, a hole depth and the like of the part is measured by a light pen measurement technology, two digital cameras are shared by the technologies, and the three-dimensional data obtained by measuring can be automatically integrated to the same coordinate system, so a three-dimensional coordinate of an object point to be measured under a world coordinate system can be obtained. The system comprises a digital projection device, two digital cameras, a T-shaped rod, a measuring head and a computer. The advantages of high efficiency and accuracy and the like of the plane structured light three-dimensional measurement technology used for measuring the complex shape of the surface can be fully exerted, and the advantages of the light pen three-dimensional measurement technology used for measuring the characteristic dimension such as the inner wall, the hole depth and the like can be exerted. The special requirements of distribution of returned light reflection index points on the T-shaped rod are avoided, and the system has the advantages of high flexibility, convenience in carrying and the like.

Description

technical field [0001] The invention belongs to the field of precision measurement, and in particular relates to a method and system for precise three-dimensional measurement of complex parts based on surface structured light and a light pen. Technology to measure feature dimensions such as inner walls and deep holes of parts. Background technique [0002] The precise three-dimensional measurement of complex parts plays an important role in the fields of industrial design and quality inspection. At present, the commonly used measurement methods are generally divided into two types: contact type and non-contact type. The traditional contact three-coordinate measuring machine has high measurement accuracy, but it is expensive and has high requirements on the laboratory environment, so it cannot realize industrial on-site measurement. Non-contact measurement systems such as structured light can quickly obtain a large number of point clouds, but there is no way to obtain the th...

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Problems solved by technology

[0003] The domestic research on light pen measurement technology has achieved certain results, such as the document "Acquisition of Feature Point Imaging Center in Probe Imaging Visual Coordinate Measurement System" published in 1998 on pages 14-20 of the fifth issue of the journal "Optical Precision Engineering" And in the document "Single Camera Measuring Probe Imaging Visual Coordinate Measurement System Modeling" published in "Journal of Instrumentation" No. 5, pp. 59-62 in 1999, a single camera measurement system is proposed, but there are limitations, such as accuracy Low, can only measure the distance, can not get the three-dimensional coordinates of the measured point; published in the journal "Optoelectronics Laser" No. 1 issue 85-88 in 2007 "Modeling of Optical Pen Type Single Camera 3D Coordinate Visual Measurement System" A hand-held visual measurement model with a single camera is proposed in the paper, and it is demonstrated that the single-camera light pen measurement system can measure three-dimensional coordinates in space, and a prototype is developed, but the model requires the hand-held light pen mark points to be strictly on a straight line, which increases the It is difficult to process, and it will inevitably bring some errors; in 2008, the document "Light Pen Type Three-Coordinate Measurement System Based on Binocular Stereo Vision" published on the 8th issue of the journal "China Mechanical Engineering" on pages 896-899 proposed A binocular stylus measurement model, but it still requires the marking points pasted on the stylus to be strictly on a straight line, and there are also disadvantages such as difficult processing and difficult to guarantee accuracy.

In addition, the light pen measurement technology can only measure one feature point data at a time, the measurement efficiency is low, and it is impossible to efficiently measure the three-dimensional data of the complex surface of the component surface

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