Research method for error analysis of line-structured optical sensors based on reflected polarized light characteristics

Measurement accuracy is affected by both random and systematic errors arising from the calibration process. Random errors are unavoidable, while systematic errors can be analyzed. Systematic errors are divided into camera calibration errors, calibration errors of the optical plane, and sensor measurement errors. The main errors in these three aspects come from the influence of physical factors such as light intensity, angle of incidence, and image quality. In order to further improve the measurement accuracy, this paper proposes a research method to analyze the error of a line structure optical sensor based on the characteristics of reflected polarized light. The relationship between light intensity and angle of incidence is analyzed by the polarization characteristics of light reflected from the surface of an object. Further, the optimal polarization angle solution model of the polarizer is established by using the Stokes vector, and the relationship between the polarization angle and the angle of incidence is investigated, and the optimal angle of incidence of the laser is calculated at the optimal polarization angle. The optical streak image is acquired, the calibration of the optical plane is carried out, and the 3D measurement of highly reflective objects is performed according to the calibration results. The method well integrates the influencing factors of the main error sources of the line-structured optical sensors systematically so that they interact with each other to form a complete system of error assessment and measurement. Errors caused by physical factors such as light intensity, angle of incidence, and image quality are effectively reduced, thus significantly improving the measurement accuracy. Experimental results demonstrate that the proposed method achieves a calibration accuracy of 0.0425 mm (RMSE), which is nearly three times higher than that of the comparative method (0.1280 mm). In actual measurements, the root-mean-square error (RMSE) for the metal gauge block and cylinder is reduced to 0.0353 and 0.0458 mm, respectively, effectively validating the high precision and robustness of the system.