Ice area and 3D ice shape measurement method based on polarized light imaging

Aircraft icing is a severe threat to safe flight. The conditions and efficiency of current ice area and 3D ice shape measurement methods do not meet the research requirements for ice wind tunnel experiments. To address these issues, we propose a method for measuring ice area and 3D ice shape based on polarized light imaging for non-contact measurement. In this paper, we obtain p-polarized light image and s-polarized light image of the experimental area under the linearly polarized light environment. And we use the Otsu algorithm and the SAM (Segment Anything Model) algorithm to measure the ice area under different substrate conditions. On this basis, we extract the linearly polarized light reflected from the ice surface, and reconstruct the 3D ice surface shape by combining the linearly polarized laser scanning method based on polarized light imaging. The experimental results indicate that our method can detect the ice area in real time and the average measurement error of the ice area is less than 1.6%, which achieves superior measurement performance with different ice types at a low cost. For different ice shapes of highly transparent ice, the measurement results agree well with the design data, where the RMSE (Root Mean Square Error) of ice frustum measurement is 0.76 and the RMSE of three cross-sections of different ice shapes are 0.23, 0.27 and 0.45. The results verify the validity of ice area measurement based on polarized light imaging, and demonstrate the effect of complex ice shape measurement based on polarized light imaging, laying a foundation for the real-time measurement research in the ice wind tunnel.