Research On Vision Measurement System Based On The Structured Light

Three-dimensional measurement is applied widely in various fields such as biomedicine,industrial detection,and cultural relics protection,and with the rapid development of technology and economy,the requirements for measurement are becoming higher.As a kind of non-contact measurement technology,structured light vision measurement has the advantages of high precision,high efficiency,and simple structure.This thesis focuses on the key technologies and system implementation of line structured light vision measurement.The main contents are as follows:(1)Research on design and calibration of structured light vision sensor system.The selection of CCD camera,lens,laser and other hardware equipment was completed,and though analyzing the imaging model and the errors under different structural parameters,the best structure between the camera and the laser in the vision sensor system was designed,and the distance and angle between the two are 100 mm and 28°,respectively;on this basis,a two-step calibration method is used to calibrate the camera parameters,and the calibration method of the structured light plane is optimized based on the principle of constant cross-ratio.(2)Research on processing method of structured light images.The characteristics of structured light strips and the factors affecting the quality of the light strips are analyzed,and based on experimental analysis,appropriate image preprocessing methods are selected,including image grayscale,cropping,filtering and segmentation operations;at the same time,the advantages and disadvantages of different structured light center coordinate extraction algorithms are studied,and an extraction algorithm that combines the Hessian matrix method and the geometric center method is proposed,the extraction speed of the new method is increased by 48% while the accuracy is still at the sub-pixel level.(3)Research on design and construction of structured light vision measurement system.A measurement system is based on structured light visual sensor,the structure of this system includes visual sensing system,motion control system and computer software system;and the system software function modules are completed based on Python language,Open CV image processing library and Qt designer interface design software.(4)Experimental tests and analysis of the measurement system.The high-precision calibration block is used to test the measurement accuracy of the system.The results show that the measurement error of the system can be controlled within 1%.In addition,the scanning and reconstruction experiments are carried out on objects of different materials and shapes.The results show that the point cloud data obtained can reflects the detailed information of the surface of objects.