Abstract: A method and system for correcting luma data and chroma data from a composite signal for a plurality of lines are disclosed. The method and system include correlating line data of the composite signal from a portion of the plurality of lines to provide a plurality of correlation signals. The method and system also include generating a chroma suppression signal based on the plurality of correlation signals. The chroma suppression signal indicates whether to suppress a portion of the chroma data. The chroma suppression signal indicates that the portion of the chroma data should be suppressed when a large luma transition and the chroma data being beneath a threshold are detected.

Abstract: A video decoder for decoding a composite video signal. The decoder includes an analog-to-digital converter (ADC), an input resampler, and a Y/C separator, all coupled in series. The ADC receives and digitizes the composite video signal to generate ADC samples. The input resampler receives and resamples the ADC samples with a first resampling signal to generate resampled video samples. The Y/C separator receives and separates the resampled video samples into luminance and chrominance components. The Y/C separator includes a delay element configured to receive the resampled video samples and provide a variable amount of delay. The variable amount of delay can be adjustable from line to line, and is typically based on an approximated duration of a video line.

Abstract: Disclosed are an apparatus and a method for YC separation and three-line correlation detection with high accuracy, which allow the YC separator to generate reliable Y signals. The correlation detecting apparatus includes a sub-correlation detector. The detector checks input signals for the presence or absence of vertical correlation, and provides the signals with a judgment “high-correlation exists” or “otherwise”. According to the judgment, the correlation detecting apparatus changes the process; i) when accepted the judgment “high-correlation exists”, the apparatus determines the judgment to be reliable and adopts it as the output, ii) when accepted “otherwise”, the apparatus increases its detecting accuracy and provides the signals with multi-leveled outputs according to the correlation levels. In this way, the main apparatus switches the detecting mode according to the result from sub-correlation detector, with the detecting accuracy greatly improved.

Abstract: A system and method for determining whether to process a signal using three-dimensional comb filtering. Various aspects of the present invention may comprise method steps and system components that generate an inter-frame chroma signal. Various aspects may generate a filtered inter-frame chroma signal by removing a band of frequency components from the inter-frame chroma signal that generally corresponds to chroma signal components. Various aspects may analyze the filtered inter-frame chroma signal to determine whether three-dimensional comb filtering may be appropriate. Various aspects may comprise method steps and components that generate inter-frame and intra-frame luma signals. Various aspects may generate filtered inter-frame and intra-frame luma signals by removing frequency components from the inter-frame and intra-frame luma signals, respectively, that fall outside a frequency band near the chroma sub-carrier frequency.

Abstract: A system and method for improved comb filtering. Various aspects of the present invention may comprise method steps and system components that generate a signal indicative of the quality of a field-combed signal. A first signal indicative of inter-field and inter-line signal difference substantially inside the chroma frequency band may be generated. An indication of field comb quality may be determined based at least in-part on the first signal, and a corresponding signal may be generated. Various aspects of the present invention may comprise method steps and system components that generate a comb-filtered signal. A field comb signal and line comb signal may be generated. A comb-filtered signal may be generated based on the field comb signal, line comb signal, and the signal indicative of the field comb quality.

Abstract: A method and system for performing combing for PAL luma data is disclosed. The combing is performed for a display having a plurality of lines. The display is capable of depicting a frame including a horizontal boundary having a top edge and a bottom edge. A top line of the plurality of lines is at the top edge of the horizontal boundary. A bottom line of the plurality of lines is at the bottom edge of the horizontal boundary. The method and system includes providing a feedback multiplexer, a line delay and a feed forward multiplexer. The feedback multiplexer has a first input, a second input and a first output. The first input is for receiving luma data for a current line. The line delay has a delay input and a delay output, the delay input coupled with the first output. The delay output is coupled with the second input. The feed forward multiplexer has a third input, a fourth input and a second output. The third input is coupled with the delay output.

Abstract: A simulated burst gate signal and a video synchronization key are generated. A video decoder generates a horizontal sync pulse which is programmed to envelop a color burst, thereby simulating a burst gate signal. The offset to the horizontal sync pulse due to simulating a burst gate signal may be compensated at a video memory subsystem receiving the horizontal sync signal, in order to determine when active pixels are provided by the video decoder. Alternatively, counter circuitry external to the video decoder may be used to generate a simulated burst gate signal by counting the number of pixel clock cycles between the horizontal sync pulse and the color burst. Unlike a burst gate signal generated within a video decoder for use with color separation circuitry in the video decoder, a simulated burst gate signal allows for use of color separation circuitry external to the video decoder. Detecting a color burst using external color separation circuitry is thus also disclosed.

Abstract: A luminance (Y) and a color difference (C) signal separator switches filters according to an image and separates a Y signal and a C signal included in a composite color picture signal to eliminate a degradation which would otherwise be involved at a transition point because of the characteristics of the filters. A first weighting circuit calculates the weighted average of the C signals extracted from the composite signal by a comb filter and a three-line comb filter. A second weighting circuit calculates the weighted average of the C signals extracted by the three-line comb filter and a two-line comb filter. When the motion level of the image exceeds a predetermined threshold, a selector selects, as the final C signal, the signal output from the second weighting circuit. When the motion level is equal to or lower than the predetermined threshold, the selector selects, as the final C signal, the signal output from the first weighting circuit.

Abstract: An image format converting method and apparatus are provided. The image format converter includes a pre-filter for pre-filtering the input image and for outputting a pre-filtered signal, and a format converter for bi-linear interpolating the pre-filtered signal, according to a predetermined aspect ratio, and for outputting a format converted signal. Therefore, the image format converter can have simple structure by adding the pre-filter, before the format converter using simple bi-linear interpolation, so that the image can be enlarged or reduced while remaining distinct and without aliasing.

Abstract: A method and system for performing combing for PAL luma data is disclosed. The combing is performed for a display having a plurality of lines. The display is capable of depicting a frame including a horizontal boundary having a top edge and a bottom edge. A top line of the plurality of lines is at the top edge of the horizontal boundary. A bottom line of the plurality of lines is at the bottom edge of the horizontal boundary. The method and system includes providing a feedback multiplexer, a line delay and a feed forward multiplexer. The feedback multiplexer has a first input, a second input and a first output. The first input is for receiving luma data for a current line. The line delay has a delay input and a delay output, the delay input coupled with the first output. The delay output is coupled with the second input. The feed forward multiplexer has a third input, a fourth input and a second output. The third input is coupled with the delay output.

Abstract: An adaptive filter is disclosed comprising a source (1) for a television signal (f), a delay device (2) for forming delay signals (v0 to v5) from the television signal, a filter combination (3) comprising at least one comb-up device and one comb-down device (3.4, 3.1) for forming filter signals (s1 to s4) from the delay signals, a mixer (5), a decision device (4) for analyzing the delay signals (v0 to v5), and a computing matrix (7) for forming weighting factors (g) for the mixer (5). A manually controllable or data-controllable setting device (8) is coupled to the decision device (4) for changing the mixing behavior in the mixer (5), which is dependent on a predetermined algorithm in the decision device (4) and/or the computing matrix (7).

Abstract: A method and circuit thereof for detecting uncorrelated lines of chrominance of a composite video signal. A threshold level for determining whether lines of chrominance are correlated is defined. A comb filter is then used to separate the chrominance information from the luminance information of a composite video signal. In one embodiment, readings for three consecutive scan lines of chrominance are taken. If any of the adjacent scan lines contain the same color information or the difference is less than the threshold level, the scan lines are correlated. Otherwise, the adjacent scan lines are uncorrelated. If the lines are uncorrelated, a band pass filter is used to separate the chrominance component from the composite video signal. If the lines are correlated, the separation performed by the comb filter was appropriate and no other action is necessary.

Abstract: Adaptive comb filter circuitry is responsive to chrominance vector absolute values to inhibit hanging dots. Chrominance vector absolute values are calculated by delaying bandpass filtered video signal to concurrently provide a plurality of sample absolute values. The plurality of sample absolute values are weighted and summed. The maximum and the minimum of the plurality of sample absolute values are selected and respectively weighted. The weighted maximum and minimum are combined with the sum of weighted samples to provide approximated chrominance vector absolute values. Exemplary circuitry is illustrated which develop real time chrominance vector magnitude values within 1.5-% p-p error. The vector magnitude approximation circuitry may be used for calculating vectors represented by successive samples which do not have an orthogonal relationship.

Abstract: A video signal decoder including a comb filter characterised by means for changing the operating mode of the filter progressively. Also, a video signal decoder including a comb filter characterised by means for adjusting continuously the degree of filtering performed by the filter. In one arrangement the decoder comprises an input filter and two signal multipliers wherein one of the multipliers is connected to receive a signal output by the input filter and the other multiplier is connected to receive a signal output by the comb filter wherein operation of the multipliers is mutually interdependent.

Abstract: An adaptive video filter and method utilizes a first filter coupled to receive a composite video signal and generate a filter luminance output signal. An amplitude detector receives the filtered luminance output signal and generates an amplitude level to an amplitude threshold analyzer. The amplitude threshold analyzer has a selectable threshold to provide a selected range of false color filter coefficients to a programmable filter. The programmable filter may be part of a programmable false color filter bank and receives the luminance information and adaptively filters the luminance information based on the selected false color filter coefficients to facilitate false color compensation by attenuating false color frequency components in the filter means information.

Abstract: A method and system for separating chrominance and luminance information from a composite spectral signal is disclosed. The method and system comprises demodulating the composite signal prior to separation of the chrominance or luminance information to provide a first U subcomponent and a first V subcomponent and then processing and filtering the first U subcomponent and the first V subcomponent to provide a second U subcomponent and a second V subcomponent, respectively. The method and system also includes combining the second U subcomponent and the second V subcomponent to provide the remodulated chrominance information. In so doing chrominance information is provided in which artifacts are substantially attenuated.

Abstract: In analog color television transmission methods, the transmitted CVBS signal comprises luminance and chrominance signals which have to be separated from one another in a television receiver in order to permit separate further processing. Comb filters can be used for this, a picture contents-dependent controller frequently being worked with which switches over between different filter algorithms, that is to say different line combinations, as a function of the respective chrominance signals. In the case of conventional comb signals, the CVBS signal is split into the luminance signal and a chrominance signal which is still to be demodulated into the two color difference signals. In this case, the identification of color edges, in particular, is not always carried out in a manner free from errors. This can lead to only incomplete separation of the luminance and chrominance signals, so that cross effects cannot fully be avoided.

Abstract: A 2-line YC separation device comprising a delay circuit for delaying a composite input video signal for a horizontal scanning period; a first band-pass filter which receives the composite input video signal; a second band-pass filter which receives the output signal of the delay circuit; a Y-correlation detector which receives the output signal of the band-pass filter; a C-correlation detector which receives the output signal of the band-pass filter; a difference detector for detecting a Y signal differential value; a YL-correlation detector for detecting a Y signal correlation; and an AND circuit for logically ANDing the output signals of the YL-correlation detector and the Y-correlation detector.

Abstract: A comb filter arrangement comprising at least one delay circuit and an adder, this adder being twice supplied with a video signal modulated on a carrier, which video signals are applied mutually shifted with time. The signals are delayed by the delay circuits, so that either video signal applied to the adder is delayed relative to the other video signal by a given period of time. Furthermore, the delay circuits are arranged in switched capacitor technique.

Abstract: For activating or deactivating the comb filter function with pixel precision, a comb filter arrangement including a delay circuit (3) and a first matching circuit (1) having at least two storage cells, these circuits receive a picture signal, having a sequence of individual pixels applied to the comb filter arrangement. The output signals of the delay circuit and the first matching circuit are superposed by a superposition stage (4) supplying a filtered picture signal from its output. The matching circuit (1) is implemented in such a way that it gives the picture signal applied thereto substantially the same amplitude variations as the delay circuit (3), and that the difference between the delay of the output signals from the delay circuit (3) and the matching circuit (1) corresponds to a nominal value.

Abstract: A circuit for separating composite video signals into luminance and chrominance signals in response to motion of a displayed image. A motion detecting section detects motion of an image to be displayed on a television screen according to input composite video signals in order to generate motion sensing signals corresponding to motion of the image. A first comb-filtering section adaptively comb-filters input composite video signals in a vertical direction according correlation among three continuous horizontal scanning lines to separate input composite video signals into first comb-filtered chrominance signals and first comb-filtered luminance signals. A second comb-filtering section adaptively comb-filters input composite video signals in the time direction in response to a correlation between frames in order to separate the input composite video signals into the second comb-filtered chrominance signals and the second comb-filtered luminance signals.

Abstract: A comb filter for use in a video decoder is described. The comb filter includes a line memory for storing as successive pairs of U and V samples of a decoded video signal corresponding to a previous horizontal line of video information and a line memory for storing a second previous horizontal line of video information. The filter also includes a circuit to calculate an average value of both U and V from a previous sample and a corresponding sample from a previous line. The filter also includes a circuit for calculating a correction term for each one of the averages. The correction term is calculated from the opposite color component as was used to calculate the average value.

Abstract: A luminance and chrominance signal separating apparatus includes an A/D converter for A/D converting an input composite color television signal by a frequency of eight times of a color subcarrier frequency; a decimation filter for converting the A/D converted digital video signal into a signal with a frequency of four times of the color subcarrier frequency; a chrominance signal separating circuit for extracting a chrominance signal from the signal which was thinned-out by the frequency of four times of the color subcarrier frequency; an interpolating filter for converting the separated chrominance signal into a signal with a frequency of eight times the color subcarrier frequency and outputting a chrominance signal; a delay device for delaying the A/D converted digital video signal by a delay time which occurs when the A/D converted digital video signal passes through the decimation filter, the chrominance signal separator and the interpolating filter; and a subtracting circuit for subtracting the chrominanc

Abstract: A technique for effectively separating luminance and color signals from a composite video signal in an NTSC-type television system sampled at 4 times the color subcarrier frequency in an NTSC type picture processing system includes steps for (1) delaying the composite video signal through a plurality of line and sample delay elements and then generating a plurality of sample signals; (2) detecting the correlations between a predetermined reference sample signal and the sample signals in the neighborhood which are in phase with the predetermined reference sample signal and then delaying the composite video signal; (3) determining any direction in which the luminance and color signals are separated and filtered; (4) separating and filtering the luminance and color signals from the composite video signal in the determined direction or in a plurality of predetermined directions; (5) detecting the vertical and horizontal correlation of sample signals which are out of phase with the reference sample signal and are

Abstract: A video comb filter for PAL or NTSC TV standards separates luminance and chrominance signals from a composite video signal by adaptively selecting between at least two different filtering processes, depending on whether the chroma output of the processes is "legal" (is within certain limits) in terms of both magnitude and phase. The present comb filter has a two horizontal scan line delay, and is such that the magnitude and phase of a chrominance signal output from the filter never exceeds that of a single band pass filtered version of the composite video and subsequently does not invert the phase of the luminance signal. The chrominance output signal characteristic is similar to that a four scan line filter; however, because the present filter only uses two lines of delay, any vertical cross luminance occurs across only two scan lines and the diagonal luminance resolution is significantly improved. The output of the comb filter is "legal" (within the RGB color cube) at all times.

Abstract: A device that separates a luminance signal and a chrominance signal from an input composite color television signal, suppressing cross color interference and keeping a good color transient characteristic, by selecting characteristics of the color bandpass filters according to a vertical correlation value after obtaining a chrominance signal at an adaptive type comb filters.

Abstract: A luminance signal/color signal separator circuit having an input terminal and luminance and color output terminals includes a comb filter connected between the input terminal and the color output terminal; an amplitude detector having an input connected to the color output terminal; a filter having a first input connected to the input terminal and a second input connected to an output of the amplitude detector; and a combiner having an output connected to the luminance output terminal, a first input connected to the input terminal and a second input connected to an output of the filter. The separator circuit processes a composite signal which includes an original luminance signal and an original color signal. The filter passes a gain controlled color band signal.

Abstract: A device that separates a luminance signal and a chrominance signal from an input composite color television signal, suppressing cross color interference and keeping a good color transient characteristic, by selecting characteristics of the color bandpass filters according to a vertical correlation value after obtaining a chrominance signal at an adaptive type comb filters.

Abstract: A decoder using an adaptive non-separable digital filter has a correlation control circuit that generates from a composite video signal a set of filter coefficients for the non-separable digital filter. The filter coefficients are a function of a correlation angle for the image represented by the composite video signal. The non-separable digital filter, using the set of filter coefficients determined by the correlation angle, separates the composite video signal into its luminance and chrominance components. The non-separable digital filter may be approximated by a set of discrete filters having a common input, with each output being multiplied by a correlation factor, the correlation factors being the filter coefficients. The resulting multiplicands are summed to produce the separated luminance and chrominance components.

Abstract: A vertical impulse detecting circuit 104 detects the difference between a level of data of a present horizontal line of an input composite picture signal and a level of data of each of a horizontal line a plurality of lines ahead and a horizontal line a plurality of lines behind. Either an output signal of a three-line chrominance signal separating circuit 100 or an output signal of a horizontal chrominance signal separating circuit 101 is selected as a chrominance signal (CC) that is supplied to a subtracter 105 according to an output signal of the vertical impulse detecting circuit 104.

Abstract: For realizing more accurately a signal separation of a luminance signal and a chrominance signal, a signal separation automatic adjusting circuit in a YC separation comb filter includes an amplitude adjusting loop for detecting a level of a color signal component remaining in the separated luminance signal to adjust amplitudes in an image signal and a 1H delayed image signal, a first phase adjusting loop for adjusting phases of the image signal and the 1H delayed image signal which are respectively inputted into an adder, and a second phase adjusting loop for adjusting phases of the image signal and the 1H delayed image signal in the manner of suppressing the color signal remaining in the luminance signal. According to the constitution, it is possible to prevent an intermix of the color signal component into the luminance, thereby obtaining the YC separation automatic adjusting circuit having a high accuracy.

Abstract: A luminance and chrominance signal separating apparatus includes a first delay device for delaying an input chrominance color television signal by one horizontal period and a second delay device for delaying a reference signal one horizontal period. An output of the first delay device is regarded as a reference signal. Two correlation detectors detect correlations between the reference signal and the signals separated from the reference signal by one horizontal period. A black level detector detects a black level of the reference signal. Filters separate a chrominance signal from the reference signal. A selector selects one of the outputs of the filters based on the output of the correlation detectors and the output of the black level detector. A bandpass filter limits a bandwidth of the selector output and outputting a chrominance signal. A subtracter subtracts the chrominance signal obtained from the bandpass filter from the reference signal and outputs a luminance signal.

Abstract: A luminance and chrominance signal separation circuit in which, when its comparing circuits decide that the level of high-frequency components of a luminance signal is lower than a predetermined level, a switching circuit, controlled by a control circuit, selects and outputs a chrominance signal output from a BPF processing circuit.

Abstract: A decoder that provides simultaneous horizontal scanning lines for digital color video, and then band splits each line into high and low frequency signals using low pass filters and subtractors to subtract the low frequency signals from the source video. The high and low frequency signals and the source video for each line is fed to a three tap comb filter, and the high and low frequency signal inputs to the comb filter are also fed to a vertical transition detector that demodulates the high frequency signals, and then provides differences between pairs of lines for luma, chroma magnitude, and chroma phase. The difference signals are used to provide a control signal that automatically switches the comb filter from a three line weighted comb to a two line comb when large vertical transitions are detected in luma, chroma magnitude, or chroma phase.

Abstract: In a circuit(s) which separates luminance and color signals of the digital color television, the present invention can reduce the noise as a circuit which adaptively performs the 1H comb filtering or the 2H comb filtering according to the correlation between upper and lower horizontal scanning lines of three successive horizontal lines when the luminance and color signals from an input video signal are to be separated. Also, even if the irregular video signal is applied, the present invention can reduce the artifact(s), by passing it without comb-filtering operation.

Abstract: An apparatus for separating a luminance signal and a chrominance signal from a video signal includes a subtractor for obtaining a difference (first subtract signal) between the original composite video signal and a one line-delayed video signal and a difference (second subtract signal) between the one line-delayed video signal and a two line-delayed video signal, an adder for adding the first subtract signal to the second subtract signal, a line correlation detector for detecting a correlation between adjacent horizontal scanning lines, and a multiplexer for selecting one of the first subtract signal, the second subtract signal, an add signal from the adder, and an output signal from a band pass filter which band pass-filters the one line-delayed video signal, in response to an output signal from the line correlation detector whereby the apparatus provides improved resolution, thereby assuring excellent picture quality.

Abstract: Color image data of which background is removed is converted into monochrome data and noise in the monochrome data is roughly discriminated in a first noise discrimination process. At the same time, the color and density of an attentional pixel, information area including a character or a picture, and others are checked, according to which operations the resulting first noise discrimination data is corrected in a second noise discrimination process. Substitute data is created from the image data of which background is removed according to the first noise discrimination data, and the substitute data substitutes for a pixel regarded as noise in the second noise discrimination process to obtain an image from which noise is eliminated. With the above arrangement, noise having a high density and noise having a size greater than the scanning window are eliminated without receiving influence from the surrounding noise.