Operation mode recognition of surface microdischarge based on the gray level histogram

A visible image of gas discharge contains rich information. This study investigates the visible light information of surface microdischarge (SMD) under different operation modes and develops a method to realize online monitoring of the operation modes based on a gray level histogram (GLH). Two SMD sources were used to verify the effectiveness of the method. The distribution curve in the GLH gradually shifted to a large gray level as the operation mode transferred from ozone mode to NOx mode. The mean, variance, energy, entropy, and uniformity threshold values used to distinguish the operation modes were found to be approximately the same in both sources. Finally, a simplified distribution map based only on entropy and uniformity is proposed for the fast operation mode recognition of SMD. In this paper, we investigate the visible light information of surface microdischarge (SMD) under different operation modes. The distribution curve in the gray level histogram gradually shifted to a large gray level as the operation mode transferred from ozone mode to NOx mode, and the trend is similar in both plasma sources. A simplified distribution map based only on entropy and uniformity is proposed for the fast operation mode recognition of SMD.