Abstract: The gravity centered coding shall be improved with respect to false contour effect disturbances on plasma display panels for example. Therefore, there is provided a GCC code (gravity center coding) and a motion amplitude of a picture or a part of a picture. Furthermore, there is provided at least one sub-set code of the GCC code. The video data are coded with the GCC code or the at least one sub-set code depending on the motion amplitude. Thus, it is possible to reduce the number of coding levels if the motion increases. A further improvement can be obtained by using texture information for selecting the GCC code.

Abstract: A method and a device for encoding the video level of a pixel of a picture into a subfield code word in a display device using a PWM (Pulse Width Modulation) technology and subfields for displaying video picture. The bits of the subfield code word are computed recursively one after the other from the bit having the most significant weight to the bit having the least significant weight. In determining the state of a bit of the subfield code word, a first threshold and a second threshold is associated with the bit, the second threshold being greater than the first threshold, and the video level to be encoded by this bit and its following bits in the subfield code word are compared to the first and second thresholds. A state is allocated to the bit based on the comparison.

Abstract: The present invention relates to a method for displaying an image in an active matrix display device and more particularly in an active matrix OLED (Organic Light Emitting Display) display. The purpose of this invention is to increase the video dynamic range of each color component. The voltages applied to the OLED cells are based on reference voltages or currents. According to the invention, a different set of reference voltages is used for each color component. To this end, the video frame is divided into at least three sub-frames and at least one color component of the picture is addressed during each subframe with a set of reference voltages adapted to said color component.

Abstract: A picture quality when reducing the brightness or the contrast of the picture on a plasma panel shall be improved. For this purpose there is provided a driving apparatus including brightness/contrast control means for receiving video input data for modifying the video levels of the video input data in accordance with external adjustment data and for outputting modified video data. First power measurement means measure a power level of the modified video data and supply a first power level. Second power measurement means measure a power level of the video input data and supply a second power level. Generator means generate a third power level comprised between the first power level and the second power level or equal to the larger one to data processing means. The data processing means calculate the maximum number of sustain pulses per frame applicable to the modified video data on the basis of the third power level and control the display of the modified video data on the plasma display panel.

Abstract: An addressing method for sample and hold displays suitable for multi-scan applications (supporting several frame rates) shall be provided. Thus, there is disclosed a method for displaying a picture on a display screen including the steps of providing an input signal including a sequence of plural frames, each corresponding to a single picture, temporally dividing each frame having a frame duration into sub-fields and controlling a display element of the display screen on the basis of the sub-fields. The number and/or duration of sub-fields of each frame is automatically adapted to the frame duration of the frame. Furthermore, the amplitude of a sub-field controlling signal corresponding to the last subfield of each frame may be automatically adapted to the frame duration of the frame. Such display methods provide for a high grayscale quality and linearity even if the frame rate is not stable nor well-defined.

Abstract: A method for evaluating video quality of a video stream comprising the steps of a) calculating, for at least a first frame of a series of frames from said video stream, a true value of at least one video quality-related parameter associated to said first frame; b) calculating a predicted value of said video quality-related parameter for at least a second frame from said series of frames based on said true value associated to said first frame; c) calculating a true value of said video quality-related parameter associated to said second frame; and d) judging the video quality of said second frame based on a difference between true and predicted values of the at least one video quality-related parameter associated to said second frame.

Abstract: A method for processing video data for display on a display device having a plurality of luminous elements comprising: applying a dithering function based on single ones of said luminous elements to at least part of said video data to refine the grey scale portrayal of video pictures of said video data, computing at least one motion vector from said video data, and changing at least one of the phase, amplitude, spatial resolution and temporal resolution of said dithering function in accordance with said at least one motion vector when applying the dithering function to said video data.

Abstract: The invention relates to a method for processing video pictures, the video pictures consisting of pixels digitally coded, the digital code word determining the length of the time period during which the corresponding pixel of a display is activated, wherein to each bit of a digital code word a certain activation duration called sub-field is assigned, the sum of the duration of the sub-fields according to a given code word determining the length of the time period during which the corresponding pixel is activated, said method comprising the following steps: detecting the video pictures source mode and the parity between pictures, if the source is in film mode, distributing the total number of sub-fields used for two frame raster in three groups of sub-fields and assigning to a value of a pixel a code word that corresponds to the distribution of the active sub-fields period over the three sub-fields groups, and if the source is in camera mode, distributing the total number of sub-fields used for each frame r

Abstract: The invention relates to a method of estimating motion between two video frames. According to the invention, the motion estimation is done by using first one motion estimation in the horizontal direction and then one motion estimation in the vertical direction. Preferably, a plurality of motion estimations in the horizontal direction are used alternately with motion estimations in the vertical direction. It allows reducing the complexity of the estimation.

Abstract: The invention relates to a method and a device for encoding the luminance value of a pixel of a picture into a subfield code word in a display device. It can be applied to every display device using a PWM (Pulse Width Modulation) technology and subfields for displaying video picture. It can be used to compensate for any luminance problem that can be estimated. The general idea of the recursive coding is to encode one sub-field after the other in order to be able to compensate for problems occurring on one sub-field with the other sub-fields. More particularly, the bits of a subfield code word are computed recursively one after the other such that the defects (e.g. line load and/or linearity) in the light emission or luminance generated by a bit of the subfield code word can be compensated by the following bits of the subfield code word.

Abstract: The present invention relates to a method and an apparatus for controlling the power level and/or the contrast in a display device having a plurality of luminous elements corresponding to the colour components of the pixels of a picture, wherein the luminance generated by each of said luminous element is based on the intensity of the signal supplied to the luminous element and the power level and/or contrast for each picture is controlled by adjusting the intensity of the signal to be supplied to each luminous element. The invention is applicable to organic light emitting displays (OLED). According to the invention, the intensity of the signal to be supplied to each luminous element is based on reference signals and the adjustment of the signal intensity is made by adjusting the level of the reference signals.

Abstract: Response fidelity problems appear for some specific video levels at PDP borders. The reason is that some cells at the border of the PDP panel are not completely closed and pollute when switched ON neighbouring cells being OFF. Therefore, it is suggested to encode the video levels in the border area in a specific way. Especially, for critical sub-fields within the code it is forbidden to insert a binary 0 between two binary 1. Thus, the neighbourhood of critical sub-fields being ON and OFF is avoided. Preferably, the specific border coding is performed under the control of an average power management and codewords being not used are recreated by dithering.

Abstract: The invention deals with the large area flicker effect reduction in display devices like plasma display panels, in which the light output is controlled by small pulses over a whole frame period and the amount of small pulses determine the brightness of the light output. The invention proposes an adaptation of the known principle of sub-field grouping for large area flicker reduction for the specific sub-field coding process called incremental sub-field coding, in which only those sub-field code words are taken for display driving having the characteristic that there is never a sub-field inactivated between two activated sub-fields or never a sub-field is activated between two inactivated sub-fields. For this specific sub-field coding it is proposed to make the sub-field grouping in a simple manner, where all the odd sub-fields are grouped together in one group (G1) and all the even sub-fields are grouped together in a second group (G2).

Abstract: A display system including a plurality of display units shall be supervised as to its proper functioning as well as the right content to be displayed. Therefore, there is provided a display device and a corresponding method for monitoring the presentation of a video signal on a display screen having a plurality of screen drivers. A mark signal is added to the video signal and a mark (13) is displayed within a picture on the basis of the video signal including the mark signal. The mark is sensed by a specific sensor and a corresponding sensing signal is provided. In order to supervise the functioning of each screendriver a specific mark signal is added for each screendriver into the video signal. Each of the plurality of marks is sensed and specific sensing signals are provided for each of the plurality of marks.

Abstract: A plasma display panel is a pure linear display and does not provide a non-linear gamma behavior 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: For improving the grey scale portrayal, several dithering methods are used: Cell-based dithering, multi-mask dithering or error diffusion. Each of them has specific disadvantages. A simple combination of them does not bring expected advantages. However, an improvement is obtained if the result of the multi-mask dithering is used for controlling the error diffusion by a switch, for example.

Abstract: The invention relates to a method for processing video data to be displayed on a display device having a plurality of luminous elements corresponding to the pixels of a video picture, wherein an error diffusion step is applied to at least a part of said video data to refine the grey scale portrayal of said video picture, said error diffusion step comprising, for each current pixel of said part of video picture, a step of truncating the value of the corresponding video data and a step of diffusing the truncation error to at least one neighboring pixel. According to the invention, a noise is inserted on the error before and/or after its diffusion to the neighbouring cells. Owing to this principle no static pattern should be visible, improving the overall picture quality.

Abstract: CMOS image sensors are usually suffering from fixed pattern noise and random defect pixels. However, for economical reasons and in order to increase the manufacturing yield, some random defective pixels are usually accepted even for professional devices. In this case, the defect pixels are usually corrected by signal processing.

Abstract: The invention relates to a method and a device for coding video levels of pixels of a colour component of a picture to be displayed on a display device into code words. The invention is more particularly applicable to Plasma Display Panels (PDP) to improve the picture quality (grayscale enhancement, dynamic false contour reduction). The main idea of the invention is to automatically change the floor and ceiling levels used classically for dithering each pixel value depending on the neighboring pixels of the same color component. The size of the window determining the neighboring pixels is dependent on the definition of the wanted flat field size.

Abstract: The present invention relates to an apparatus for displaying an input picture of a sequence of input pictures during a video frame made up of N consecutive sub-frames, with N?2, comprising an active matrix comprising a plurality of light emitting cells, encoding means for encoding the video data of each pixel of the input picture to be displayed and delivering N sub-frame data, each sub-frame data being displayed during a sub-frame, a driving unit for selecting row by row the cells of said active matrix and converting, sub-frame by sub-frame, the sub-frame data delivered by said encoding means into signals to be applied to the selected cells of the matrix. According to the invention, at least one of the N sub-frame data generated for a pixel is different from the video data of said pixel.