The Key Technology Research Based On Three-Line Structured Light Measurement

The three-dimensional intelligent measurement technology has extensive development and application whatever in automobile,machinery manufacturing or reverse engineering and some other frontier areas.And the non-contact optical 3D measurement method is a hotspot of research in recent years.However,the domestic development of portable measuring instrument has a certain gap compared with abroad,which mainly rely on import.Thus,The article firstly designs a three-line structured light measurement system which is theoretically based on the multi-line structured light measurement method,which also independently studys and designs projection and imaging module of the system.And DSP is used as the core of image processing system.The system is used to measure local features of the surface with the design goal of structure simplification and size miniaturization,which provides further basis for the research of portable measuring instrument used in the industrial manufacture area such as detection of car door gap and engine cover.Now LCD or digital projectors are mostly adopted by multi-line structured light measurement method,whose illumination of multi-beam stripe is realized by computer code.This method has the advantages of speediness when measuring the overall surface topography of objects.However,too many stripes cause the waste of resources as measuring local features of the surface(such as gap,radius,offset and so on)in this article,and projectors have large volume and high cost.Therefore,the article firstly puts forward three-line structured light for measurement,with some new designs and improvements,mainly for the following research work:Firstly,three-line structured light measurement method is firstly proposed through the analysis of the structured light measurement principle.And the determination of projection angle rule is discussed,which is based on the multi-line structured light coding combining with characteristics of three-line structured light.Secondly,Powell lens and rectangular grating are firstly used together to design the projection light source module of three-line structured light measurement system.The Powell lens is proposed to make Gaussian beam from the semiconductor laser into flat-hat beam.Besides,the feasible scheme of three-line beam is discussed based on the analysis of the rectangular grating diffraction principle.The whole projection light source module is simulated in ZEMAX to verify the feasiblity.Thirdly,the relevant parameters of imaging optical system are determined according to the technical indicators of the three-line structured light measurement system,which also matched with parameters of the CCD sensor.And the structure of optical system is optimized in ZEMAX according to these parameters until achieving the required requirements.Besides,the fast image processing after CCD acquisition is analyzed in the paper.Finally,the experiment is conducted according to simulation results and the measurement result is obtained by calculating and analyzing images,which is to validate the principle feasibility of three-line structured light measurement.