Image Processing of Discharge Pattern by Spatial Fourier Transform Method

In this paper, the method of Spatial Fourier Transform has been used to investigate the pattern formation dynamics in a dielectric barrier discharge (DBD) system. With this method, patterns formed in the DBD system can be transformed into smooth frequency spectrum. The frequency constitution of discharge pattern can be analyzed. In our experiment mixed gas of 96% Ar and 4% air at 0.9 atm is used as working gas. The experimental results show that the discharge pattern with increasing the applied voltage undergoes a scenario: stochastic discharge filaments, hexagon pattern, square pattern, honeycomb structure. The different kinds of patterns were transformed into Fourier space by two-dimension Spatial Fourier Transform. The spectra of patterns were given and analyzed in this paper. It was found that different discharge patterns correspond to different frequency spectrum, furthermore, the better the stability of the pattern, the clearer the frequency spectrum. Therefore, the pattern transition procedure from one discharge pattern to another can also be studied by the frequency spectrum. Consequently, Spatial Fourier Transform is a better method to research the pattern formation dynamics in gas discharge system.