Abstract: A subject of the invention is to ensure that a remote display device is only useable for a specific application like advertising or public information. According to the invention, this object is solved by a method for distributing display information to a remote display device, comprising the steps of: providing the remote display device with a signal comprising an activation key and the display information, providing the control unit of the remote display device with a locking function using a control key, and comparing the activation key to the control key and authorizing the displaying of the display information by deactivating the locking function if the activation key is fitting with the control key.

Abstract: The invention relates to a reproduction device, with a device acting as a source of digital services. It also relates to a method of synchronizing two parts of a digital service in a system including a source device according to the invention and at least one reproduction device according to the invention. According to the invention, the reproduction device includes means for receiving the data forming at least a part of a digital service originating from a digital service source device, means for processing at least some of the data received, means for reproducing an output of at least a part of the digital service, the time for processing and reproducing the data introducing a delay in the output of the reproduced data. This device also includes communication means for informing the source device of the delay introduced.

Abstract: Phosphor based display technologies show artefacts like “sticking” or “ghost” images produced by “marking” or “burn-in” effects. In order to remove these artefacts, it is proposed to activate a portion of the display screen as a wiper and to move the wiper at least one time over the complete display screen or a part of the display screen. The wiper will homogenize the complete video screen in order to make the ghost images less visible. Another embodiment is dedicated to the reduction of the short-term burning effect. Here, a dynamic correction of the displayed picture is done. A memorized picture could be subtracted from the current picture in order to reduce the visibility of the short term sticking effect.

Abstract: The invention relates to a method and apparatus for processing video pictures, in particular for large area flicker effect and false contour effect reduction. This method concerns a new coding called Parallel Peak Coding. The general idea of the Parallel Peak Code is to have almost always the same energy in two packets of light and to encode the code words for these two packets differently so that changes in sub-field code word will not appear in the two packet code words simultaneously.

Abstract: The invention relates to a method for processing video pictures data for display on a display device having a plurality of luminous elements corresponding to the pixels of a video picture. The invention is related to every kind of display devices based on the principle of duty cycle modulation (pulse width modulation) of light emission and comprising a data driver. The aim of this method is to reduce the data driver overheating by optimizing the dithering of the pixel values of the video pictures. According to the invention, the pixel values used for dithering are chosen for reducing the state changes between successive bits of subfield code words of adjacent luminous elements.

Abstract: Plasma Display Panels (PDP) are becoming more and more interesting for TV technology. Due to the larger size of PDPs, with larger viewing angle the large area flicker effect will become more serious in the future, in particular when handling 50 Hz video standards. This invention proposes a different sub-field organisation, with different coding, which reduces large area flicker artefact, and which is characterised by: 1. Grouping of sub-fields (SF) in 2 sub-field groups (G1, G2), of similar structure. 2. Adjusting the starting times of the two sub-field groups to a time raster corresponding to a doubling of the frame repetition rate by adding a first blanking period of a first dedicated length behind the last sub-field of the first sub-field group and a second blanking period of a second dedicated length behind the last sub-field of the second sub-field group.

Abstract: The invention concerns a video processing for improving the picture quality of picture which are displayed on display devices like plasma display panels and all kind of display devices based on the principle of duty cycle modulation of light emission and for reducing the average power dissipation. The basic idea behind the invention is to generate only the required amount of sustain pulses that effectively produce light and to avoid generating unnecessary sustain pulses. To this end, the video range of the input video is increased in order to be equal to a nominal range, 255 in the case of a 8-bit coding, and a power level mode with a reduced number of sustain pulses is selected to keep constant the brightness of the image. The number of sustain pulses that do not produce light is reduced.

Abstract: The invention relates to a new method for power level control of a display device and an apparatus for carrying out the method. Classically, the contrast/brightness control and the power management (based on an average power level control) are made independently. These two controls can be contradictory. According to the invention, the power level mode and more particularly the number of sustain pulses within the video frame is selected as a function of the average power level (APL) of the picture to be displayed and the picture control signal representing the desired contrast and/or brightness value.

Abstract: The invention relates to a method for power level control of a display device and an apparatus for carrying out the method. Classically, a power level mode defining a subfield organization to be used for subfield coding is selected as a function of the average power level of the picture to be displayed for keeping constant the power consumption of the display device. According to the invention, it is proposed to select the power level mode as a function of the input frame frequency in such a way as to have as little as possible deviations from nominal peak white and full white values at the same time that an overloading of the panel power supply is prevented. More particularly, the number of sustain pulses within the video frame and selected by the power level mode is modified as a function of the input frame frequency.

Abstract: The invention is related to a new kind of pre-processing for plasma display panel control. The plasma display technology has the drawback of a reduced grey scale portrayal. This is due to the fact that contrarily to CRTs where luminance is approximately quadratic to the applied cathode voltage, luminance is linear to the number of discharge pulses in PDPs. Therefore, an approximately quadratic degamma function has to be applied to the input video signal components R,G,B before sub-field coding can be done. Truncation to 8-bit video data is required, so that the effect of the degamma function cannot be fully maintained. Especially in the region of small video levels, where the eye sensitivity is high, the grey scale portrayal is poor. According to the invention it is proposed to use a new kind of dithering, adapted to the PDP specialities to improve the grey scale portrayal. These adaptation includes three dithering specialities which can be used singly or in combination. These are: cell-based dithering, i.

Abstract: The invention relates to a method for processing data of video pictures for displaying the pictures on a display device like a Plasma Display Panel. The existing false contour effect compensation methods which make a false contour compensation based on shifting sub-field code word entries along the direction of the motion vector of a current pixel, produce an artifact in the pictures, in case of object crossings. In the appearing area there is a lack of light generation. The invention solves this problem by checking whether an area exists in the picture which is currently hidden but will appear in a next frame and providing an adapted compensation method for “hole filling”. The invention also gives a solution for an improved compensation method which is based on a dragging of sub-field code word entries along a motion vector direction to a current pixel.

Abstract: The invention is related to a new kind of plasma display panel control. A known principle for PDP control is based on a combination of sub-field addressing and priming. Within the priming period all the plasma cells of the panel are pre-excited by a strong voltage pulse. This treatment of the cells produces a slight background luminance which is a drawback for picture quality aspects because the achievable contrast is reduced. According to the invention it is proposed to use self-priming sub-fields and refreshing sub-fields instead of this hard priming period. With these concepts it is assured that the cells which ought to be black remain black. Self-priming sub-fields reduce or eliminate the need for priming, thus making dark areas darker, while refreshing sub-fields, can be addressed faster. In practice, the number of refreshing sub-fields in a frame period is higher than the number of the self-priming sub-fields. Therefore, the total addressing time can be reduced with this new technique.

Abstract: Plasma Display Panels are becoming more and more interesting for TV technology. One important criterion for picture quality is the Peak White Enhancement Factor PWEF. In a previous patent application a method for power level control in a display with which the PWEF can be increased has been proposed. With an increased PWEF the problem of local overheating of plasma cells may occur. This invention proposes a protection circuit, which deals with this problem. For protecting the plasma display against local overheating, there is provided a method, which performs the steps of local power value determination, local temperature estimation, maximum local temperature determination and maximum power level limit determination. The power level limit influences the power level control process in the display device so that local overheating is avoided and the highest possible PWEF can be used. The invention also concerns a corresponding apparatus for carrying out the proposed method.

Abstract: A plasma display panel is a pure linear display and does not provide a non-linear gamma behaviour like a CRT so that an artificial gamma function has to be applied to the signal in digital form. This gamma function increases the quantization steps in the dark areas whereas the quantization steps will be reduced in the luminous areas. The basic idea is to apply an adaptive noise filtering after the gammatization process. The adaptive filtering is a specific filtering which is adapted to the gammatization quantization noise. In other words, the filtering will be maximum for dark areas and its efficacy will be automatically decreased when the luminance of the area is increasing.

Abstract: With the new plasma display panel technology new kinds of artefacts can occur in video pictures due to the principle that brightness control is done with a modulation of small lighting pulses in a number of periods called sub-fields. These artefacts are commonly described as ‘dynamic false contour effect’. To compensate for this effect motion estimators are used and with the resulting motion vectors corrected sub-field code words are calculated for the critical pixels. Today's motion estimators work with the luminance signal component of the pixels. This is not sufficient for plasma displays. It is therefore proposed to make the motion vector calculation separately for the color components and with either the sub-field code words as data input or with single bit data input for performing motion estimation separately for single sub-fields or for a sub-group of bits from the sub-field code words. The proposal also concerns apparatuses for performing the inventive method.

Abstract: The present invention relates to a method for improving grey scale fidelity portrayal of pictures displayed on matrix display screens. The method comprises the following steps: a) for a given peak white level, distributing the sustain pulses among the sub-fields, the number of pulses corresponding to the sub-field weighting, b) mapping the sub-field codes to luminance codes, c) re-ordering luminance codes in a definite order, d) mapping the video levels to the available luminance codes, e) processing the video levels to achieve intermediate levels of luminance f) then, mapping luminance codes to the output sub-field codes. The method is used in plasma display panels (PDP).

Abstract: With the new plasma display panel technology new kinds of artifacts can occur in video pictures. These artifacts are commonly described as dynamic false contour effect, since they correspond to disturbances of grey levels and colors in the form of an apparition of colored edges in the picture when the observation point on the PDP screen moves. According to the invention such an artifact is compensated by analyzing the motion in the pictures assigning to each block of a picture a corresponding motion vector and performing a re-coding step in which a sub-field code word entry of a current pixel are calculated. For this purpose the motion vector is defined to point from a pixel in a previous picture to a pixel in the current picture. The sub-field code word entries for a current pixel (P8) are determined by dragging sub-field entries of the pixels lying on the motion vector trajectory.

Abstract: When the observation point on a PDP screen moves, artifacts will be introduced which are commonly described as “dynamic false contour”. A simple way to reduce this effect requires the use of more sub-fields at the expense of panel brightness. A first idea called Bit-Line-Repeat (BLR) makes it possible to exchange vertical resolution with addressing time in order to dispose of more sub-fields for the same brightness. Nevertheless, such a solution introduces some vertical artifacts mostly during movement. Therefore, before the step of sub-field encoding a vertically filtering of the picture divided into pixel blocks is performed, wherein each block includes at least one pixel in horizontal direction and a number of pixels corresponding to the number of common lines in vertical direction. The effect of the pre-filtering step is that the difference of brightness values within each pixel block is limited to a predetermined value.

Abstract: Phosphor based display technologies show artefacts like “sticking” or “ghost” images produced by “marking” or “burn-in” effects. In order to remove these artefacts it is proposed to activate a portion of the display screen (10) as a wiper and to move the wiper at least one time over the complete display screen (10) or a part of the display screen (10). The wiper will homogenize the complete video screen in order to make the ghost images less visible.

Abstract: Plasma Display Panels (PDP) are becoming more and more interesting for TV technology. Due to the larger size of PDPs, with larger viewing angle the large area flicker effect will become more serious in the future, in particular when handling 50 Hz video standards.