Research On 3D Measurement System Of Laser Interference Structured Light Objects Based On Embedded Platform

With the development of related products in high-tech industries such as electronics,communications,biomedical engineering and other fields to gradually miniaturize and miniaturize,the accuracy of their external dimensions has also been continuously improved,so higher current measurement technologies have been proposed.Requirements and promote their development towards high precision,integration and high speed.In the application of 3-Dimensional(3D)measurement of small-sized objects,the 3D measurement method based on laser interference fringe structured light projection has the advantages of flexible system structure,clear fringe projection,and strong environmental adaptability,and has attracted the attention of many scientists.This paper designs and develops a set of 3D measurement system based on embedded platform,and improves the system hardware structure and related software algorithms based on problems in the measurement process,and achieves good measurement results.The main work of this paper is as follows:(1)Based on the polarization characteristics of light,the laser interference fringe structured light projection and image acquisition of the measurement system are optimized,and the influence of ambient light intensity is reduced by adding a polarizer;the interference fringe image is cut to obtain the key area of the object to be measured and the noise points in the image are filtered out Then,based on the Gaussian transform function,the background light intensity of the interference fringe image is equalized to further improve the brightness uniformity of the image.(2)Designed an automatic algorithm for generating reference fringe images.By fitting a set of fringe models based on the unmodulated part of the fiber interference fringe image to replace the area where the object is located,and then optimizing according to the cosine distribution of the gray value of the fringe pixels.Finally,a complete and accurate reference fringe image is restored,which enables the extraction of phase information of the object to be measured by only acquiring an interference fringe image,which effectively reduces the measurement error caused by environmental changes in the 3D measurement system,and simultaneously improves measure efficiency.(3)The Raspberry Pi 4 was selected as the embedded development platform according to the design index requirements of the measurement system;the collected deformed interference fringe images were processed by Python programming,including phase extraction based on Fourier transform and Hilbert transform The phase unwrapping based on the least-squares algorithm of fringe contour shear.Finally,the 3D information of the object to be measured is obtained according to the mathematical model of the calibrated system structural parameters.Based on the embedded platform-based 3D measurement system designed to measure several typical small-size object models,the accuracy and time-consuming analysis of the experimental results show that the system meets the design requirements and is a laser interference structure.The optical object 3D measurement method provides a new idea,solves the technical bottleneck that the 3D measurement of tiny products and parts has high environmental requirements,and also provide key technical support for precision processing and production.