Study On Method Of Laser Interferometer Detecting Plasma Density

During the electro-explode aluminum wire will generate plasma, and Plasma generation is an important factor affecting the results of aluminum production, so detection of plasma is a necessary condition to improve the process of preparation. This paper proposes a complete solution to detect plasma’s density.In this paper, specifically, uses Mach - Zehnder laser interferometry to detect plasma’s density. Because the plasma will disturb the detecting-light phase, comparing the phase of detecting-light and reference-light will get curved fringes, which contains the information of plasma’s density. Through processing the interference fringes we can obtain this information.In this paper,we first use MATLAB to simulate interference fringes,with different electronic density we can obtain different interference fringes. These interference fringes can be used to validate experimental results. The steps for processing of actually fringes are filter, binarization and thinning. For image filtering processing, in this paper analyze and compare spatial filtering, frequency domain filtering and filtering of three partial differential treatment advantages and disadvantages, finally adopted of partial differential interference filter paper image filtering process. Fring image has the characteristics that who’s intensity distributes as cosine function. So using derivative symbol binary image method to get binaryzation image. For binary image thinning algorithm, in this paper describes the OPTA thinning algorithm, Hilditch classical algorithm, Zhang fast parallel thinning algorithms and mathematical morphology thinning algorithm, and using mathematical morphology thinning processing methods. this method can be completed with the function of MATLAB.After the image processing is completed, should to extract information of the fringes image. Actually, measuring fringes’offset can calculate each point on the curved fringes the number of shift times of interference. Finally can calculate the electron density in the plasma.The main work in this paper include some points as follows:1. analysis the whole detecting system in detail.2. Interferometric image processing and image data extraction interference specific proposals.3. Simulation fringes of different distribution density and different electron density based on MATLAB.4. Developing a software based on MATLAB which used to the detection system.