Abstract: The present invention relates to a method for improving grey scale fidelity portrayal of pictures displayed on matrix display screens.

Abstract: The invention is related two 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 he used singly or in combination. These are: cell-based dithering, i.e.

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 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.

Abstract: The invention is related two 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 (SPSF) and refreshing sub-fields (RSF) instead of this hard priming period. With these concept it is assured that the cells which ought to be black remain black. Self-priming sub-fields (SPSF) reduce or eliminate the need for priming, thus making dark areas darker, while refreshing sub-fields (RSF), can be addressed faster. In practice, the number of refreshing sub-fields (RSF) in a frame period is higher than the number of the self-priming sub-fields (SPSF).

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: The invention is related to a new kind of dithering method for plasma display panels. In a former Europena Patent Application a dithering method for the plasma display technology has been presented that utilizes a 3-dimensional dither pattern for the repeated use in a video sequence. A first dimension corresponds to a number of video frames, a second dimension corresponds to a number of video lines, and a third dimension corresponds to a number of cells or pixels in a video line. It has been found that this dither pattern has for some video levels the drawback of a generating a noticeable pattern in homogenous surfaces on the screen that reduces the picture quality.

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. According to the invention, such an artefact is compensated by analyzing the pictures, and determining the pixels which need to be corrected. The digital sub-field code words of these pixels are replaced by corrected sub-field code words. Thereby, the correction sub-fields (C1, C2, C3) which are inserted in or omitted from the digital code word are selected under consideration of its position within the frame period for optimal results.

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. According to the invention, such an artefact 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 the different sub-fields of a pixel are shifted to distribute the sub-fields of a pixel more closely on the eye trajectory.

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: The invention is related two an improved addressing scheme for plasma display panel control. In the conventional addressing scheme called ADS (Adressing and Displaying Separated), the whole panel is treated as one section and the addressing period within the sub-fields is broad because all lines of the whole panel are addressed one after the other in this single addressing period. This has the drawback that a long time distance is between writing a cell during addressing phase and light generation during the sustaining period. An improved addressing scheme has been proposed in literature, where the panel is partitioned in a number of sections and correspondingly the addressing period is split up in corresponding small addressing periods for each section. Inbetween the small addressing periods there is some light generation, so that the time distance between addressing and light emission is substantially reduced.

Abstract: A signal processing method for an analogue picture signal is proposed. In this case, the analogue picture signal originates from a computing unit (10) in which the signal was generated digitally in accordance with a graphics standard such as, for example, EGA or VGA and was subsequently converted into analogue form. The method consists in subjecting the analogue picture signal to analogue/digital conversion at a first chosen sampling frequency, after which the sampled picture is then investigated for picture disturbances, in order to determine a corrected sampling frequency. Further measures relate to the determination of the optimum sampling phase and the determination of the exact position of the active picture relative to the horizontal and/or vertical synchronization pulses.

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 method is proposed for processing transitional regions in a picture signal. The picture signal comprises a sequence of digital pixel values. A number of adjacent pixel values, which contain a processing pixel value, are combined to form a processing block. A corrected pixel value is calculated for the processing pixel value. The maximum and minimum pixel values are first determined in the processing block to define the transitional region. The transitional region is then split into a number of sections on the basis of the magnitude of pixel value. Finally, a determination is made as to the section in which the processing pixel value is located. The processing pixel value is allocated a corresponding correction value in order to increase, to reduce or to leave unchanged the processing pixel value, in accordance with a predetermined transfer function.

Abstract: The present invention is directed towards a computer monitor utility assembly to be used with a standard computer monitor. The computer monitor utility assembly includes primarily a universal mount base which is structured and disposed to be removeably, yet securely attached to the top surface of the monitor, and to a generally rigid top panel having a width generally equivalent to a width of a screen of the monitor. The top panel is adjustably secured to the mount base in overlying relation atop the monitor and so as to be able to slide forward and backward relative to the mount base, thereby selectively overhanging beyond the front surface of the monitor and providing shade to the monitor screen from light and glare. Further, the improved computer monitor utility assembly includes a utility console.

Abstract: The present invention is directed towards an improved computer monitor utility assembly to be used with a standard computer monitor. The computer monitor utility assembly includes primarily a universal mount base which is structured and disposed to be removeably, yet securely attached to the top surface of the monitor, and to a generally rigid top panel having a width generally equivalent to a width of the monitor. The top panel is adjustably secured to the mount base in overlying relation atop the monitor and so as to be able to slide forward and backward relative to the mount base, thereby selectively overhanging beyond the front surface of the monitor and providing shade to the monitor screen from light and glare.

Abstract: A first pixel of a given field is compared with second and third vertically aligned pixels of corresponding horizontal position of an adjacent field to produce, for each first pixel, a pixel difference signal having a value of zero if the value of the first pixel is intermediate the values of the second and third pixels, the difference signal otherwise having a value equal to the absolute value of a difference between the value of the first pixel and the value of one of the second and third pixels having a value closest to that of first pixel. The pixel difference signals are accumulated over a predetermined portion of one field period of the video signal to provide a field difference signal which is analyzed by a group of five correlators for patterns characteristic of 2-2 pull-down or 3-2 pull-down film mode sources. Flags are produced for identifying film mode operation and for identifying which of the adjacent fields to use in subsequent video processing such as de-interlacing or flicker reduction.

Abstract: A synchronizing signal separating circuit for a television receiver, comprising: a source of a video signal having a line synchronizing signal component; a line synchronizing signal component separator having an amplitude selective stage and having a flywheel stage imparting a response time constant to the separator which enhances noise immunity; a delay circuit for the video signal, for example a multiple line delay, coupled ,between the video signal source and the separator; a control circuit coupled to the video signal source and evaluating the time positions of line synchronizing pulses of a plurality of successive lines to identify a kind of line phase disturbance in which the line phase of an entire raster is displaced, the control circuit supplying a control signal to the separator indicative of the kind of phase disturbance; and, the flywheel stage being temporarily rendered inoperative responsive to the control signal, for example by temporarily decreasing the response time of the separator, upon ide

Abstract: A binary number is generated representative of net motion during a field interval of an interlaced video signal from which a field to field difference signal is derived having a sign bit and a group of magnitude bits. The magnitude bits are compared with a first threshold to provide a first threshold indicating signal which, with the sign bit, are applied via respective bus lines to each correlator of a group of five correlators. The correlators are addressed using variable modulo addressing to detect patterns representative of 2--2 pull down and 3-2 pull down film originated frames. Logic is provided for detecting when one and only one of the five correlators indicates film detection to verify film mode operation. Error reduction is further enhanced by comparing the field difference signal with a second threshold, higher than the first, to provide a second thresold indicating signal to each correlator via a second bus.

Abstract: Video signals of interlaced form are first converted to progressive scan (non-interlaced) form and then picture elements are generated that lie between the "progressive" picture elements and are interpolated by a vertical one-half (1/2) line shuffling by application of a vertical averaging. The interpolated picture elements are buffer stored and are read out again at twice the frame repetition rate whereby each second line of the stored interpolated picture elements is emitted delayed in time by 10 milli-seconds. Fields in the format 100 Hz, 2:1 interlace thereby ensue. Advantageously, interpolated picture elements are used in all of the output fields thereby avoiding picture disturbences at the frame rate (25 Hz) of the original video signal. For increasing the subjective vertical sharpness, a vertical peaking may additionally be carried out.

Abstract: A film mode detection method and corresponding relatively non complex hardware implementation compares the amplitudes of pixels of corresponding image areas of three successive field to determine if the pixel amplitudes are monotonically increasing or decreasing. Depending on the comparison a positive or negative polarity indication is generated and these indications are combined within each field to generate a polarity indication representing each respective field. The field sequence of such field polarity indications are thereafter compared with a predetermined pattern to determine whether the video signal is from a film or video-mode source.