Extraction of Lightning Channels from Optical Images and Calculation of Fractal Dimension

The extraction of lightning channels and the analysis of fractal dimensions are important topics in the field of lightning research. In this study, three high-speed optical images of negative cloud-to-ground flashes are preprocessed and then subjected to edge detection, contour search, and screening to extract the lightning channels. The results show that the lightning channels can be well separated from the background image. Using the box-counting method, the fractal dimensions of the extracted lightning images were calculated to be <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.31,1.31$</tex>, and 1.22, respectively. This study obtains the complex fractal dimension of the leader, which can provide basic parameters for the simulation of lightning leader development.