Research On Data Processing And Calibration Algorithm Based On Line Scanning Chromatic Confocal Measurement System

Chromatic confocal technology is a kind of non-contact measurement method,which has high precision and stability,and is widely used in the field of precision detection.Based on the point-based chromatic confocal measurement system,only the depth information of a single measurement point can be obtained in a single measurement.In order to obtain the three-dimensional surface morphological characteristics of the measured object,it is necessary to carry out two-dimensional scanning,which not only puts forward high requirements for the stability of the movement of the mechanical parts,but also reduces the scanning efficiency.In this paper,a line scanning chromatic confocal measurement system is proposed.A single measurement can obtain the depth information of thousands of measuring points on the line at the same time,and the information of measured surface can be obtained by one-dimensional scanning.This method not only greatly reduces the movement of mechanical parts,but also improves the scanning efficiency,and has a wide range of adaptability in the measurement of three-dimensional topography.This paper around the line chromatic confocal scanning measurement system design and signal processing with calibration algorithm research,the main contents are as follows:In the process of the optical system design,this paper starting from the measuring principle of line chromatic confocal scanning,combined with the actual industrial demand,fully considering the factors that affect the system performance,using ZEMAX software to complete the design and optimization of the optical radiation processing units,signal acquisition system.The performance of the whole system was verified according to the simulation results.In the study of signal processing and calibration algorithm,the influence of dark signal and system random noise is analyzed,a variety of peak wavelength extraction algorithms are introduced in detail,and the actual effects of different algorithms are compared to determine the optimal scheme.By polynomial function fitting,the stable and accurate mapping relationship between the position of peak wavelength and the depth of the measured object is obtained.The main factors affecting the measurement accuracy of the system are analyzed,and a reliable calibration scheme is proposed.This paper independently developed a simple and practical graphical user interface,and combined with the point cloud processing technology to restore the three-dimensional surface morphology the measured object,realizing intelligent and digital measurement.In this paper,a high precision nano-displacement platform was used to calibrate the system,and the metal plate and glass groove were used as measurement samples for experiments.The results show that the measurement range of the system is more than 3 mm,the resolution of the system is up to 0.7um,and the length of the scanning contour is up to 12mm,which can meet the requirements of large-area and high-speed measurement,and has a good commercial value and application prospect.