Improve extinction coefficient accuracy with optical compensation

Extinction coefficient is the base parameter of visibility measurement, its measurement error determines the accuracy of the visibility meter. In the paper, the error sources are analyzed, and a new optical structure is proposed by adding the optical compensator. For the new structure, the measurement model based on boundary constraints is provided to reduce measure errors. Based on the new model, use an improved algorithm to solve the error convergence problem. The new algorithm use exponent arctangent function as base function, three parameters i, j and k control the contour of the function. With simulation tool, the optimization values are obtained. The experimental results show that the extinction coefficient relative error is reduced by 18% in the entire measurement region, the fluctuations of the relative error is reduced to 7.3%.