Motion estimation within the MPEG video compressed domain for JET plasma diagnostics

Video cameras have recently become diagnostic tools widely used on Joint European Torus (JET) for fusion plasma diagnostic and control. Since video streams are usually compressed for storage, MPEG-2 compressed domain information is processed to obtain a very fast and reasonably accurate 2-D motion estimation of the video scenes for the JET diagnostics, whose computational costs are prohibitively high. These methods can be used for the manipulation of the large JET video databases and, in specific cases, even for real-time data processing. Plasma instabilities, which can trigger harmful disruptions, are detected and tracked by means of motion segmentation. Motion segmentation is used as a key contrivance to allow very fast optical flow estimation for the determination of the deuterium ice extrusion velocity of JET pellet injector. Experimental validation is performed on significant JET video data.