Abstract: A color processing apparatus includes an image signal acquisition section, a color conversion matrix storage section, a matrix regularization processing section and a normal color conversion section. The image signal acquisition section acquires an image signal containing a predetermined input color signal. The color conversion matrix storage section stores information of a color conversion matrix which associates the input color signal and an output color signal with each other. The matrix regularization processing section reads the information of the color conversion matrix from the color conversion matrix storage section and converts the color conversion matrix into a nonsingular matrix. The normal color conversion section converts the input color signal acquired by the image signal acquisition section into an output color signal using the nonsingular matrix.

Abstract: A method of characterizing a display having a plurality of color channels includes the steps of visually characterizing the nonlinearities of the display; determining luminance ratios of the color channels using heterochromatic photometry; determining the chromaticities of the color channels using a neutral identification process; and calculating a colorimetric mixing matrix for the display by combining the luminance ratios of the color channels with the chromaticities of the color channels.

Abstract: A digital signal processing system and method applied for chroma transition, wherein the method has the acts of: performing a difference process on an original chroma signal C to obtain a first difference signal C?; calculating an absolute value |C?| of the first difference signal C?; performing a difference process on the absolute value |C?| to obtain a second difference signal Ca?; determining whether the second difference signal Ca? is a positive signal or a negative signal; wherein based on a determined result, an optimized chroma signal is generated by either mixing the original input chroma signal C with a k-delayed chroma signal, or mixing the k-delayed chroma signal C[n?k] with a 2k-delayed chroma signal C[n?2k], where k is a constant.

Abstract: A method is disclosed for determining an adjustment amount to be made to an input chroma, Cin, to squeeze the input chroma toward a region of preferred chroma, Cpref. This method involving first defining a change in chroma as: ?C=Cin?Cpref and defining a chroma weight as: Cweight=Gaussian(Cpref,Csigma); defining a luminance weight as: Lweight=Gaussian(Lpref,Lsigma); defining a hue weight as: Hweight=Gaussian(Hpref,Hsigma);. Then, an amount of chroma adjustment is: CAdjust=?C*(Hweight*Cweight*Lweight). An output chroma is generated by applying chroma adjustment to chroma input: Cout=Cin?CAdjust.

Abstract: An apparatus for synchronizing chroma and luma data includes a first handshake block for luma data, a second handshake block for chroma data, and a means for providing a handshake signal to the first block and to the second block based at least in part on a determination that they are both ready to transfer data, and further for inhibiting provision of the handshake signal based at least in part on a determination that at least one of the first block and the second block is not ready to transfer data.

Abstract: The present invention has an object to provide a gradation correcting apparatus for correcting the gradation of the white side of a video luminance signal. The gradation correcting apparatus is provided with a maximum value detector 101 for detecting a maximum value of a luminance signal S101, a white comparator 102 for comparing the luminance signal S101, a maximum luminance value S111 detected by the maximum value detector 101, and a first white threshold value S103, a white linear converter 103 for performing linear conversion on the luminance signal S101 on the basis of the maximum luminance value S111, the first white threshold value S103, and a second white threshold value S104, and a white controller 104 for correcting the luminance signal S101 on the basis of the result of the comparison in the white comparator 102, the output of the white linear converter 103, and the second white threshold value S104.

Abstract: A display controller provides luminance values to a display, where values for contrast and brightness for the display are constructed within a gamma correction mapping table. The display controller has an original gamma correction mapping table, a gamma correction transform circuit and a transformed gamma correction mapping table. The original gamma correction mapping table contains entries describing a default luminance value to be provided the display for a magnitude of a video input signal. The gamma correction transform circuit receives entries from the original gamma correction mapping table and from the contrast signal and brightness signal, transforms the entries to transformed luminance values. The transformed luminance values are placed in the transformed gamma correction mapping table. The transformed gamma correction mapping table receives a video signal that provides a pointer to the luminance values to be used to drive the display.

Abstract: A video encoder capable of adjusting output levels and more effectively utilizing performances of later devices, provided with a level adjustment circuit for adjusting output levels of an input luminance signal, color signal, and composite video signal by adding DC offset in accordance with a value set in a register or the like in advance and outputting the same to a display device, and an image processing system using the same.

Abstract: A database table reorganization is defined to permit online access of the table during the reorganization. Records are reorganized in the database table by vacating records from a defined number of pages and then filling the pages with records in accordance with a desired ordering for the records. Temporary pointers to the new locations of moved records are used to prevent table scanner access to the database table from missing or duplicating records while scanning the database table during reorganization. Removal of the temporary pointers is synchronized with the completion of scanning of all table scanners that are commenced during a time when records are being moved as part of a vacating or filling step.

Abstract: A multiplexed video signal interface in accordance with the present invention provides a multiplexed component video signal which includes component video signals with OSD data and user-controllable contrast and video gain, along with the ability to individually control such signal components. This advantageously minimizes the complexity of the necessary signal interfaces and allows for greater integration of circuit functions, thereby significantly reducing circuit complexity, size and costs. Also provided is a signal peaking circuit in the form of a variable high pass filter that enhances the magnitudes of the higher frequency signal components of the component video signals and OSD data, thereby providing for sharper edges on the displayed images.

Abstract: An interface circuit 13 is provided for a display apparatus 3 such as a television. The display apparatus 3 comprises a video signal processing circuit 8 for processing a composite video signal to derive color component signals having variable black and white levels; a linear amplifier 10 for amplifying the color component signals; and a display device 4 such as a CRT driven by the output of the linear amplifier 10. The interface circuit 13 is provided to interface the color component signals with a digital signal processor 14. The interface circuit 13 includes a modification circuit 22 arranged to perform a modification of voltage levels of the color component signals and to output the modified color component signals to the digital signal processor 14 via an A/D convertor 18.

Abstract: An image processing apparatus operates to process signal samples in a form of color reference signal samples representative of at least part of a color video image to produce legal color signal samples representing a legal color version of the image. The apparatus comprises a color conversion processor arranged to receive the input signal samples and which operates to convert the color reference signal samples from a unipolar form, to bipolar form on a scale between two maxima having opposite polarity, an adjustment factor generator, which operates to generate a plurality of adjustment factors which when combined with the input signal samples have an effect of converting illegal color pixels of the color image into legal color pixels, and a color legalizer coupled to the adjustment factor generator, which operates to combine the adjustment factors with the input signal samples to produce the legalized color signal samples.

Abstract: A PLL architecture with fast phase acquisition, a stable freerun output frequency, and post-freerun fast phase recovery. The invention is particularly well suited for use in a video graphics a/d conversion circuit. An intelligent phase lock loop is optimized to determine the time difference between the closest rising edge of an PLL output signal and the rising edge of an input signal. The time difference in combination with the current PLL lock state determine an operational code used in a digital signal processing loop filter used to control a digitally controlled oscillator. The PLL also provides a stable output frequency during freerun periods, and a phase booster circuit for post-freerun fast phase recovery.

Abstract: A system and method for converting color images divides a first image into first RGB values per pixel, determines which of the RGB colors in the first image has a greater specific gravity, converts the first RGB values into second RGB color values based on the color with the greater specific gravity, and forms a second image based on the second RGB values. The color value conversion involves allocating a first number of bits to represent the second RGB value corresponding to the color having the predetermined specific gravity and a second number of bits to represent the RGB values corresponding to remaining ones of the colors. The first and second numbers of bits are different and preferably the first number is greater than the second number. Through this system and method, an M-bit color image may be converted into an N-bit color image with greater color accuracy than other methods which have been proposed.

Abstract: An image processing apparatus operates to process signal samples representative of at least part of a color video image to produce legal color signal samples representative of a legal color version of the image.

Abstract: The invention provides a circuit for controlling a cathode ray tube. The circuit comprises a source of input color signals (Uin(R), Uin(G), Uin(B)) for the primary colors of the cathode ray tube. Output amplifiers are coupled to the source of color input signals and to electron guns of the cathode ray tube. Finally, limiting means are provided to limit the color input signals to a predetermined threshold value. In this way the output amplifiers are prevented from saturation and undesirable smears do not appear on the screen. In an advantageous embodiment the limiting means are realized by a diode biased in reverse direction.

Abstract: Device and method for decoding a television video signal are suggested. The device includes a tint controller and a color space converter. The tint controller converts a plurality of color space converting coefficients which is used for converting color space signals into R, G, B signals into tint considered coefficients having a tint control considered. On the other hand, the color space converter produces the R, G, B signal displayable on a monitor by using the tint considered coefficients from the tint controller and the color space signals.

Abstract: An image processing apparatus operates to process input signal samples representative of at least part of a color video image to produce legal color signal samples representative of a legal color version of the image. The apparatus comprises an adjustment factor generator, which operates to generate a plurality of adjustment factors which when combined with the input signal samples have an effect of converting illegal color pixels of the color image into legal color pixels, an adjustment factor biasing processor coupled to the adjustment factor generator, which operates to change the adjustment factors by combining each of the adjustment factors with a biasing constant, and a color legalizer coupled to the biasing processor, which operates to combine the biased adjustment factors with the input signal samples to produce the legalized color signal samples.

Abstract: A color modification system and method for reducing the number of computations performed on a pixel color. This reduction in computations increases the rate at which color modification may be performed and decreases the effects of rounding errors. Decreasing the effects of rounding errors produces a more accurate color modification, thereby reducing the likelihood of artifacts. The system and method performs color modification on a pixel color, where the color includes a first, second, and third component and each component defines a value of the color. The system includes a chroma lookup table having a plurality of entries. Each entry corresponds to a luma value and contains chroma coefficients. The chroma coefficients define color modifications to be applied to the components of the color. If a luma value is received, the chroma lookup table generates output chroma coefficients at an output.

Abstract: The system and software of the present invention presents a process for translating a source palette containing TV unsafe colors into a resultant modified palette containing only TV safe colors, while preserving the color trends in the source palette. The software will first analyze a source color palette to determine the TV unsafe colors contained therein. For each TV unsafe color in the source color palette, the software determines the closest TV safe color by selecting a TV safe color that is the shortest Euclidean distance from the TV unsafe color. The TV unsafe colors are substituted with the calculated TV safe colors and stored in the resultant palette. The software will divide the color space of the source palette into discrete regions, e.g., by Hue (H), by selecting reference colors as the boundaries of the regions. The initially TV safe color will then be modified in a manner similar to the modifications made on nearby reference colors that were required to make them TV safe.

Abstract: An information processing apparatus is connected to a plurality of application devices. A memory section in the information processing apparatus stores, by unit of object corresponding to the application equipment, an input data type for each object and output data type for each object. The user indicates a first object as a serving side object and a second object as a receiving side object from among the plurality of the objects through an indication section. A retrieval section retrieves a third object whose input data type is the output data type of the first object and whose output data type is the input data type of the second object from the memory section, if the output data type of the first object is different from the input data type of the second object. A control section assigns the third object between the first object and the second object as a relay object.

Abstract: The present invention relates to a chrominance signal processing apparatus and method for providing optimal color processing according to the hue of the color image data. Red, green and blue signals are input to a chroma composition ratio determination circuit that generates and outputs the RGB color composition ratio (&agr;:&bgr;:&ggr;). A chroma suppression luminance signal generating circuit then generates a chroma suppression luminance signal Ya based on the RGB signals and the color composition ratio. A chroma suppression gain determination circuit outputs the gain for the chroma suppression luminance signal based on a table in which output gain setting values corresponding to the chroma suppression luminance signals are recorded. Multipliers then multiply input color-difference signals Cr, Cb by the gain and output a suppressed color-difference signals (Cr×G, Cb×G) according to the color composition ratio (&agr;:&bgr;:&ggr;).

Abstract: A method and apparatus for transforming color signals. The transformation is achieved by use of a first, coarse, look-up table and a second look-up table that provides coefficients to be used in calculating a correction vector. The vector of color components from the first look-up table is added to the correction vector to provide the transformed vector. The method and apparatus have particular application in the display of digital video signals.

Abstract: An analog-to-digital converter for converting an analog television signal to a signal in compliance with a digital encoding standard is provided.

Abstract: An interface is realized that can prevent video signals from being copied easily and which uses a luminance/color difference signal transmission scheme with an excellent harmony with a television circuit. In a video transmission using a digital interface, colorimetry information for defining the conversion from the luminance/color difference signal into a primary color signal and video aspect ratio information are transmitted along with the luminance/color difference type video signal. This allows reproduction of video with high quality and high resolution and also realizes a copyright protection which allows only the users authorized by key information to use the content of the video. With this transmission scheme, it is possible to provide a transmitting apparatus, a receiving apparatus and an interface which highly harmonize with a rationalized television-based circuit.

Abstract: In an S-video signal processor, the luminance signal is amplified and adjusted over selected frequency ranges using a parallel signal for shaping the S-video signal response and permitting the S-video signal to be transmitted over exceptionally long transmission lines while providing a quality picture. In separate channels, chrominance and luminance signals are amplified and impedance matched. A luminance band pass filter permits manual adjustments to a lower range of video signal frequencies and thus changes to white level picture information. One version of the S-video signal processor includes a positive feedback network which permits user adjustments in an upper video signal frequency range having picture super detail information for providing a picture of high resolution and thus pleasing to the user. In a second version a compensation amplifier is used to alter the frequency response of the luminance signal.

Abstract: A color modification system and method for reducing the number of computations performed on a pixel color. This reduction in computations increases the rate at which color modification may be performed and decreases the effects of rounding errors. Decreasing the effects of rounding errors produces a more accurate color modification, thereby reducing the likelihood of artifacts. The system and method performs color modification on a pixel color, where the color includes a first, second, and third component and each component defines a value of the color. The system includes a chroma lookup table having a plurality of entries. Each entry corresponds to a luma value and contains chroma coefficients. The chroma coefficients define color modifications to be applied to the components of the color. If a luma value is received, the chroma lookup table generates output chroma coefficients at an output.

Abstract: A chrominance signal processing apparatus in a video signal processing system which has a simple configuration capable of achieving chrominance signal control and RGB transform functions using a single circuit.

Abstract: An image processor includes a determination unit which determines an adaptation ratio of a reference white color value with respect to at least two white color values. Also included are a calculation unit which calculates a reference white color value in accordance with the determined adaptation ratio, and a conversion unit which converts an image signal in accordance with the calculated reference white color value.

Abstract: A color conversion apparatus in which an output result of a color converting circuit at a succeeding stage for color-converting a specific color can be prevented from being affected by an output result of a color converting circuit at the preceding stage for color-converting a whole image. A first color converting circuit color-converts a whole image of image data in a first color-conversion fashion. A second color converting circuit color-converts only the area of such color in a second color-conversion fashion by adding a correction signal which results from multiplying a key signal indicative of an area of specific color to image data in which the whole image is color-converted in a first color-conversion fashion. A key signal generating circuit generates the key signal from the image data supplied to the first color converting circuit.

Abstract: A reference signal having either twice or four times the frequency of a color burst signal (2fsc or 4fsc) is divided into a plurality of divided signals, each having the same frequency as that of the color burst signal, or an fsc frequency. In addition, a reference signal is delayed by a predetermined amount to thereby generate a delay signal. One of the divided signals is output in synchronism with this delay signal as a first divided signal having a predetermined delay. When this first divided signal is used as a color burst signal, the remaining divided signals resultantly all have phases shifted by a predetermined amount with respect to the color burst signal. With this arrangement, some of the divided signals can be used intact as a color signal, while the others may also be used after being delayed by a predetermined amount.

Abstract: Image data of the respective colors are converted, by look-up tables in which &ggr; correction data are stored, into gradation data that are white-balanced with intervention of the V-T characteristics of liquid crystal panels. The generated gradation data are supplied to D/A converters and the liquid crystal panels via liquid crystal driving circuits. Gamma correction data within dynamic ranges that are set for each display apparatus by measuring a luminance ratio and contrast ratios of the respective colors are written to the look-up tables in advance. As a result, all they correction data stored in the look-up tables can be used effectively. The invention is directed to such a method for generating data of look-up tables and an image display apparatus that performs gradation correction by using thus-formed look-up tables.

Abstract: A color encoder is incorporated in an apparatus for reproducing a signal recorded on a disk for a video-CD, CD-G, or similar system. The color encoder serves as an interface between such an apparatus and a television receiver. The color encoder has a color-difference signal forming circuit for forming a color-difference signal from R, G, and B signals reproduced from a disk, a modulation circuit for modulating a chrominance subcarrier with the color-difference signal, and chrominance subcarrier generating device for generating the chrominance subcarrier. Moreover, to generate a chrominance signal having the same frequency for any of a plurality of clocks having different predetermined frequencies, the chrominance subcarrier generating device has a plurality of ROMs, each containing in its data area a data table corresponding to a different frequency, and a ROM switching circuit for selecting a ROM to be accessed from among the plurality of ROMs in accordance with a switching signal.

Abstract: A video line connection apparatus for adaptively connecting external input/output lines, the apparatus capable of flexibly selecting an output by responding to the external line which is connected to an input jack. The apparatus includes: a plurality of composite video input jacks; a plurality of Y/C separated video input jacks; at least one composite video output jack; at least one Y/C separated video output jack; a first multiplexer; a second multiplexer; a third multiplexer; a luminance/chrominance signal separating unit; an on-screen path control unit; a chrominance signal path control unit; and a control unit. The apparatus offers convenience to the user and dispels the user's uneasiness caused by improper connection of video lines.

Abstract: Color display pixels taken in localized groups are transformed from RGB color signals intended for a self-luminous display into WCMYRGBK signals to drive a chromatophore color display device. Each chromatophoric pixel is of one solid color and is selected from the group (White, Cyan, Magenta, Yellow, Red, Green, Blue, Black). Input luminosity resolution is maintained as output brightness resolution and color fidelity is preserved for the localized group. Separate totals are developed for the Red, Green and Blue components of pixels in a pixel group. A step-repeat process selects a specific chromatophore color for each pixel. As a pixel of the group is processed a chromatophore color is selected which best matches pixel color and the RGB components of the selected chromatophore color is subtracted form the group color totals. Very bright pixels are represented by White, light pixels are represented by Cyan or Yellow or Magenta, dark pixels are represented by Red or Green or Blue.

Abstract: An image display device is arranged to convert analog video signals into digital video signals and display the corresponding image to the digital video signals. The image display device provides a variable delaying circuit for delaying an analog video signal of each color or a clock variable delay circuit for delaying a dot clock for generating each color dot clock and supplying each color dot clock as a conversion timing signal of an analog-to-digital converting circuit of the corresponding color. This kind of delay circuit is served to adjust a phase of the analog video signal or the dot clock of each color, thereby suppressing color blur even if the analog video signal contains skews among the colors.

Abstract: A video display apparatus includes: storage means for holding connection information on connections between a external input terminals and external units corresponding thereto; and switching control means for performing control so that each terminal not connected to the corresponding external unit among the external input terminals is skipped based on the connection information stored in the storage means when the switching of the external input terminals is performed. The switching of the external input terminals is controlled by the steps of: previously storing the connection information on connections between the external input terminals and the external units corresponding thereto in a memory; referring to the stored connection information when the switching of the external input terminals is performed; and skipping each external input terminal not being connected to the corresponding external unit, based on the result of the referring.

Abstract: A gamma correction circuit for a television receiver includes a low pass filter for filtering a luminance signal gamma-corrected in a transmitter side and outputting a low frequency zone component luminance signal, a luminance signal corrector for compensating for a high frequency zone component with regard to a color signal transmitted from the transmitter side and the low frequency zone component luminance signal outputted from the low pass filter, an operator for applying a subtraction and a division with regard to the low frequency zone component luminance signal outputted from the low pass filter and the corrected luminance signal, and a color signal restoration unit for restoring a original color signal using the color signal corrected in the corrector and the luminance signal outputted from operator, for thereby being provided to a CPT (color picture tube).

Abstract: The system for viewing color video "automatically" enables and disables a color killer circuit (monochrome/color mode) so that the color video may be viewed in monochrome. Enabling and disabling the color killer circuit for the current system may be accomplished, in part, by dynamic operation of the television. In operation the user may select one of three methods of activating the monochrome/color mode to enable the color killer circuit. First, the monochrome/color mode may be activated for one or more preselected channels. Second, the monochrome/color mode may be activated for all channels. Third, the monochrome/color mode may be activated if a control signal is included within the television broadcast indicating that the particular video being received is a colorized monochrome video. To deactivate the monochrome/color mode may be accomplished by any of four deactivation methods that disable the color killer circuit. First, the monochrome/color mode may be deactivated by turning the television off and on.

Abstract: A circuit arrangement processes a color signal reproduced from a record carrier, preferably a video tape, and modulated on a carrier wave of a first carrier frequency (color-under signal). The color signal modulated on the first carrier frequency is applied to a first mixer which converts the color signal to a second carrier frequency by mixing it with a first mixing signal. An output signal of the first mixer is applied to a comb filter circuit, whose output signal is applied to a second mixer. The second mixer converts the comb-filtered signal to a third carrier frequency by mixing it with a second mixing signal, in order to achieve an optimum comb filtering. The first mixing signal is subjected to a phase shift of a given magnitude by a first phase shifter after a given number of picture lines of the color signal.

Abstract: A color image enhancement device for a video display appliance capable of improving the sharpness of the color image using a saturation component. The device includes an RGB (red, green, blue)/saturation conversion section for obtaining a saturation of an image of an RGB color model, a saturation enhancement section for emphasizing a high frequency band of the saturation outputted from the RGB/saturation conversion section to enhance the saturation, and a saturation/RGB conversion section for converting an output of the saturation enhancement section into enhanced color signals.

Abstract: A method of color correcting digital video data 21 is disclosed, comprising the steps of providing a workstation 22 connected to a source 20 of digital video data, analysing video data at the workstation 22 and making decisions relating to color corrections to be applied to the video data 21, generating color correction parameter data corresponding to the decisions, transmitting the video data and the corresponding color correction parameter data 23 to a remote color processor 28 for applying color corrections to the digital video data 26, applying color corrections to the digital video data in accordance with the correction parameter data, and returning the color corrected video data 27 from the color processor 28.

Abstract: A video signal processor for use in a multi-color standard color video apparatus including a horizontal synchronizing signal generator and a baseband circuit provided on a same LSI chip as a video signal processor. The baseband circuit includes a switched capacitor filter having a switched capacitor array. A driving pulse generator for driving the switched capacitor filter is included on the same LSI chip and synchronizes to horizontal signals in a received video signal of a particular color-standard.

Abstract: A poly phase filter for converting a sampling frequency of a digital video signal to perform a dot sequential color difference signal conversion operation, the digital video signal including a luminance signal and a color difference signal, the color difference signal including two color difference signal components. The poly phase filter is adapted to generate a plurality of poly phase filter coefficients to be used to process the luminance signal and to process the color difference signal. The poly phase filter is also adapted to process the generated poly phase filter coefficients in units of two to process the color difference signal. Therefore, the present invention has the effect of reducing the hardware size and the associated cost.

Abstract: The signals received by the three cameras of any color video system are determined by the reflectance properties of the objects in the scene and the spectral distribution function of the illuminant. Since the information of interest to the observer is determined by the scene and not by the illuminant i.e. what kind of objects, characterized by their reflectance properties, are in the scene, not how they are illuminated, it is desirable to correct the signals from the scene for the illuminant before the information is displayed on the CRT. According to the invention, a color video system employs the achromatic variable .xi., where .xi., 0.ltoreq..xi..ltoreq.1, and preferably also the chromatic variables .eta., .zeta.

Abstract: A system for converting original RGB color signals to CMY signals includes the step of separating color signals from the original image into low-frequency and high-frequency components. The low-frequency components are converted to CMY signals via a look-up table reflective of a non-linear algorithm, while the high-frequency components are converted to CMY signals according to linear algorithms. The technique avoids color distortion caused by high-frequency noise, such as from halftone screens, in the original image.

Abstract: A device for processing color data (R, G, B) of a signal representing an image. The processing device has a mechanism which, for each color data item, consist of an analog/digital converter (12, 13, 14) and a buffer memory (MT1, MT2, MT3), a circuit (PT) for processing the digital data output by each buffer memory, and serializer circuits (SE1, SE2, SE3) which collect the signals output by the processing circuit (PT) and make it possible to generate signals (D1, D2, D3) intended to reproduce the image with a slow-motion effect. According to an improvement of the invention, the control unit includes a mechanism (MO, SE4) for generating a signal (I) making it possible to reproduce the image at normal speed. The device applies particularly to television studio cameras in the professional sector.

Abstract: A digital-to-analog video encoder method and apparatus having unique equalization are disclosed. The encoder converts digital video signals into one or more analog video formats using one or more digital-to-analog converters. Equalization is provided to compensate for zero order hold effects of the digital-to-analog converters. Equalization is provided to a luminance signal and/or a chroma signal to equalize RGB, composite video, and super VHS video outputs. Multiplexed digital-to-analog converter inputs allow selection of several output formats.

Abstract: A signal processor for extracting chrominance information from a composite video signal has transversal filters developing first and second signals (A and B). A look-up table generates a control signal (C) which is a non-linear function of the ratio A/B and simultaneously develops the product B*C. A filter of this form can combine steep frequency response with minimal degradation of the response to pulses.

Abstract: An apparatus and method for updating a color look up table and expanding video data for use in various applications such as a multimedia computer. The color look up table updating scheme permits selective updating of one entry in the table or up to all of the entries in the table. Updating of the color look up table is preferably performed during the horizontal blanking period. The table may be comprised of two buffers, and a combined output of these two buffers further enhances a multiplicity of colors available to a user.