The Quality of Mass Communicated Images with Special Reference to Digital Image Processing in the Graphic Arts Industry

All visual communication technologies are composed of detection, processing and multiple copying processes. Image quality in a copy is influenced by these three processes, and in addition the principle of processing (optical, analog or digital) also plays a role. In order to characterize the relevant components of quality, a systematic analysis was carried out. Imaging technologies were compared with respect to their quality components. On the basis of the quality analysis, the possibilities of quality improvement arising from the innovation of digital image processing are discussed with particular emphasis on the graphic arts industry

Kinetic instabilities that limit {\beta} in the edge of a tokamak plasma: a picture of an H-mode pedestal

Plasma equilibria reconstructed from the Mega-Amp Spherical Tokamak (MAST) have sufficient resolution to capture plasma evolution during the short period between edge-localized modes (ELMs). Immediately after the ELM steep gradients in pressure, P, and density, ne, form pedestals close to the separatrix, and they then expand into the core. Local gyrokinetic analysis over the ELM cycle reveals the dominant microinstabilities at perpendicular wavelengths of the order of the ion Larmor radius. These are kinetic ballooning modes (KBMs) in the pedestal and microtearing modes (MTMs) in the core close to the pedestal top. The evolving growth rate spectra, supported by gyrokinetic analysis using artificial local equilibrium scans, suggest a new physical picture for the formation and arrest of this pedestal.Comment: Final version as it appeared in PRL (March 2012). Minor improvements include: shortened abstract, and better colour table for figures. 4 pages, 6 figure

Observation of confined current ribbon in JET plasmas

we report the identification of a localised current structure inside the JET plasma. It is a field aligned closed helical ribbon, carrying current in the same direction as the background current profile (co-current), rotating toroidally with the ion velocity (co-rotating). It appears to be located at a flat spot in the plasma pressure profile, at the top of the pedestal. The structure appears spontaneously in low density, high rotation plasmas, and can last up to 1.4 s, a time comparable to a local resistive time. It considerably delays the appearance of the first ELM.Comment: 10 pages, 6 figure