Study on the Normalization Method of the Influence of Detection Distance on Ultraviolet Imaging of Corona Discharge

Observe distance has significant influence on the detection result of Ultraviolet(UV) imaging, in order to normalize the detection result of different observe distance to a uniform distance, Corona discharge facular regions in UV images were segmented with image processing algorithms and the facular area parameter was defined in this paper, then using rod-plane gap corona discharge model, the facular area and photons number parameters vary characteristic with the detection distance under different discharge intensity were researched, using Least-square curve fitting algorithm, the relationship of the above two parameters with distance were analyzed, fitting analysis showed that the fitting curves approximate meet the power function relationship. According to the characteristic of fitting function's exponent value with different discharge intensity were close, the exponent value were averaged and then we got the unified fitted functions expression. Based on the above research, the normalized calculation formulas were deduced; practical tests showed that the formulas had high normalization accuracy.