ELMs filaments extraction on divertor visible high-speed camera system of EAST

Abstract In order to study the ELMs filamentary structure generated by plasma in H-mode, a tangential visible camera system was established on EAST Tokamak. However, the obtained ELMs filamentary structure cannot be accurately and quickly identified, which is not conducive to the study of ELMs filamentary structure. In this paper, the ELMs filamentary structure is preliminarily extracted by the background subtraction method. The background modeling method adopts multi-frame averaging followed by contrast stretching of the image. Although the ELMs filamentary structure can be clearly seen in the obtained image, there exists a lot of noise, so further extraction of the ELMs filamentary structure is needed. In this paper, the neural network model U-Net is used for image segmentation. Compared with the traditional threshold segmentation, the ELMs filamentary structure and noise can be accurately distinguished, and ELMs filaments are better extracted. The results show that the method presented in this paper is suitable for the extraction of ELMs filamentary structure and beneficial to the study of ELMs filamentary structure.