TLS laser intensity correction based on polynomial model

Starting from the laser radar range equation, the polynomial model is adopted to fit the relationship between the laser intensity value and the received power based on the instrumental radiometric mechanism. Because of the unknown system parameters and target reflectance, it is impossible to compute the definite received laser power. So, by constructing the new variable constituted by the combination of the cosine of the incidence angle and the square of the range, the scanning geometry factors and target reflectance are separated and the polynomial model is used to fit the relationship between the laser intensity and the new variable. The standard range and the standard incidence angle are defined, and the intensity biases caused by the range and the incidence angle are corrected by analyzing. Experiments are conducted to test and verify the proposed method. Results show that the method can effectively remove the variations and biases caused by the range and incidence angle as well as accurately obtain the corrected laser intensity value proportional to the reflectance of the scanned point.