Computer-aided reconstruction of the cathode image in high current vacuum arc from the results of high speed photography

The images of the cathode, obtained by the method of high speed photography, are of ellipsoidal form as they are taken at the small (about 10 degrees) angle to the cathode surface. For this reason it is very difficult, if possible at all, to make conclusions about the spatial distribution of cathode spots and current density over the cathode surface. One can perform inverse parallel projection, but previously it is necessary to clean the image from the noise occurring from the plasma radiation and from other noise sources. In this paper, the authors propose the method of image filtering, based on contours of equal intensity evaluation and subsequent estimation of the current density on the cathode.