Abstract: The present invention relates to a method of compensating for the differences in persistence of the phosphors in an image display screen consisting of cells arranged in lines and in columns, several adjacent cells being covered with different phosphors in order to form a pixel, the cells of one pixel being put either into an “off” state or into an “on” state for a time within one frame period depending on the grey level to be displayed. According to the method, at the pixel, the transitions between a first grey level and an adjacent second grey level are detected and if the transition is greater than a threshold the state of the cell covered with a persistent phosphor is forced to the second grey level before the end of the frame period. The invention applies especially to plasma panels.

Abstract: With the new plasma display panel technology new kinds of artefacts can occur in video pictures. These artefacts are commonly described as “dynamic false contour effect”, since they correspond to disturbances of gray levels and colors in the form of an apparition of colored edges in the picture when the observation point on the PDP screen moves.

Abstract: A process for addressing cells of a plasma panel includes the step of coding the grey levels NG1 and NG2 relating to an item of information regarding the luminance of two cells situated in the same column and in two adjacent lines I and I+1. The grey levels NG1 and NG2 are coded as a first control word corresponding to a common value VC and as a second control word and a third control word corresponding to specific values, VS1 and VS2. The coding is such that, NG1=VS1+VC and NG2=VS2+VC. The process further includes the step of transmitting the bits of the first control word on the column inputs by simultaneously addressing the two lines I and I+1 in respect of the selection of the corresponding cells.

Abstract: A video signal is applied to a kinescope having scan velocity modulation for improving picture sharpness in the vertical direction. Pictures from video signals of a type having non-interpolated and vertically interpolated lines (e.g., interlace-progressive up-converted) will tend to exhibit a significant reduction of sharpness in vertical direction. This problem is corrected by applying scan velocity modulation only to the interpolated lines of the video signal. Furthermore, the vertical deflection is restricted to horizontal structures or real vertical transitions, respectively. In order to have a high noise immunity of this sensitive processing, the resulting luminance amplitude of the shifted line as well as the vertical deflection is controlled to be strongly dependent on the current video signal (soft decision).