Abstract: This invention suppresses overshoot and undershoot at an edge of a video signal.

Abstract: An image display method displays an image by different gradation conversion in every pixel, on the basis of gradation frequency distribution of luminance of pixels near an edge of the image, and counting of gradation frequency of luminance of pixels near the edge is weighted depending on the coordinate values of each pixel so as to eliminate relative contrast drop in the image central part from the image peripheral parts.

Abstract: A system processes an image containing a first line and a second line, where the first and second lines includes a plurality of pixels, to generate an interpolated line. The system selects a first and second set of pixels from the lines and generates a first set and second set of filtered values. The system identifies in the first line an edge location in the first set of the filtered values by a first filtered value of the first set of filtered values being at least one of less than and equal to a first predetermined value and a second filtered value of the fist set of the filtered values being at least one of greater than and equal to the first predetermined value.

Abstract: A video signal is enhanced using a non-linear combination of left and right difference signals (L and R), constrained to be zero if either L or R is zero, using a minimum absolute value function. Edge enhancement is provided when the polarities of L and R are the same and peak enhancement when the polarities are different. Difference signals are derived with delays (2 and 4) and a subtracter (3). The non-liner combinations are derived in a lookup table (30).

Abstract: What is disclosed is a method for removing noise by distinguishing between edge and non-edge pixels and applying a first noise removal technique to pixels classified as non-edge pixels and a second noise removal technique to pixels classified as edge pixels. The methodology operates on images while in a Color Filter Array (CFA) domain prior to color interpolation, and uses techniques suited to the classification, whether edge or non-edge.

Abstract: A gradient is calculated at each pixel of the image data to be filtered using a one-dimensional horizontal gradient operator of 1×2 size and a one-dimensional vertical gradient operator of 2×1 size, each of the gradient operators having a weighted value (1,−1). The absolute value of the calculated gradient is then compared with a predetermined threshold value to generate a binary value. This gradient calculation and comparison with a threshold is repeated for pixel blocks having a predetermined size to generate a binary edge map with respect to a whole block. A filter window of a predetermined size is then applied to the generated binary edge map to determine whether edges are present in the filter window. If no edges are present in the filter window, then the pixel values of the corresponding filter window pixel are filtered pixel-by-pixel by using a predetermined first set of weighted values to generate a new pixel value.

Abstract: A receiver including an NTSC rejection filter for eliminating interference signals from a high definition signal. The ratio of the energy of an expected high definition signal to the energy of an NTSC signal is determined. An NTSC signal sequence is generated according to the determined ratio. The number of filter taps is determined, and an autocorrelation matrix of the NTSC signal is calculated using the generated NTSC signal sequence. The power of all interference noise in the output of the NTSC rejection filter is used as a cost function, with respect to the input NTSC interference signal, the additive Gaussian noise and the VSB signal. A filter coefficient equation, for minimizing the cost function, is obtained by differentiation, and then the autocorrelation matrix is substituted for the equation, to calculate coefficients of the NTSC rejection filter.

Abstract: An contour correcting circuit for correcting the contour without deterioration of image quality of the video signal, comprising a first HPF for extracting the high frequency signal component of the video signal supplied from an input terminal Tin, a second HPF for differentiating the output of the first HPF additionally, and a correlator for synthesizing the output signals of the output and the inverted output of said first HPF, and the output of the second HPF to form a signal having a predetermined signal waveform, wherein the correlator forms a signal waveform of the preshoot portion and overshoot portion with the first order differential output which is relatively static at the inflection point of the video signal, synthesizes a second order differential waveform so as to be a sharp signal waveform at the middle portion, and performs sharpness processing of the video signal by use of the contour correction signal.

Abstract: An apparatus and method for improving the clarity of a picture produced from a video signal. A differentiation circuit is provided that produces a responsive correction signal. Mechanisms for adjusting the shape (width, amplitude, etc.) of the correction signal are disclosed. Disabling the correction signal during blanking intervals and synchronization is also disclosed, among other features.

Abstract: Apparatus for processing video signals and which can be connected with a personal computer for further processing. An analog to digital converter samples and converts input NTSC composite video signal into digital signal for subsequent processing. A phase-locked loop provides sampling clock signal to the ADC, and also ensures accurate sample phase. Based on a theory that human eye is more sensitive to the luminance component of video signals, a double sampling circuit is included which double samples the luminance component of a video signal to improve the overall resolution of an image.

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: Aperture correction or edge detection circuitry filters input data for high-frequency components, and then selects areas most likely to be text based on the contrast of the signal and applying an amount of aperture correction responsive to the signal characteristics. A high pass filter (116) is employed to filter out low frequency components and separate the signal into positive and negative going transitions. Then, the positive-going signal is coupled to a contrast detector (124), which produces a control signal that controls the amount of aperture correction added to the signal by an aperture correction circuit 112. The contrast detector (124) is designed to generate an amount of aperture correction that is responsive to the high frequency content of the positive-going signal. In one embodiment, a global threshold is used that allows aperture correction to be applied to the input signal only if the amplitude of the high frequency component of the signal is greater than the threshold.

Abstract: The present invention provides a technique for obtaining a sharp video image from a plurality of frames during a multimedia teleconference. Video data is acquired by a camera on a first processing system in the form of a number of frames. The frames are transmitted to a second processing system, which combines corresponding pixel values from each of a series of initial frames to produce an output frame. The process is repeated to generate a number of output frames, which are displayed on the second processing system.

Abstract: A sharpness processing method and apparatus, and a storage medium storing a program, for presenting images with increased perspective or three-dimensional effect. At least two points are designated in a direction of distance on an original image displayed on a display screen. The original image is divided by lines extending perpendicular to and touching opposite ends of a vector defined by the two points. An output image in the proper perspective is obtained by applying no processing to a near view area in the original image, applying a uniformly strong blur processing to a distant view area, and processing an intermediate area in a way to increase blur gradually in the direction indicated by the vector.

Abstract: An MPU changes the phase of a sampling clock signal by one step for each frame until the change in the phase reaches 360 degrees. An image quality detector portion sequentially receives a digital image signal to detect a maximum one of data about the absolute value of a difference between adjacent pixels in one frame as an image quality judgement data signal. The MPU detects a maximum one of all image quality judgement data to determine a phase at that time as an optimum phase of the sampling clock signal. The MPU then periodically checks image quality on a screen, and makes a real-time correction to the phase of the sampling clock signal if a temperature drift or the like occurs.

Abstract: In a contour correction apparatus, a first sample is selected from among at least five plural samples of an input digital video signal as an indication of an upper limit value. The plural samples correspond to neighboring pixels respectively. The first sample has a value greater than a center value among values of the plural samples. A second sample is selected from among at least the five plural samples as an indication of a lower limit value. The second sample has a value smaller than the center value among the values of the plural samples. High-frequency signal components are generated with respect to a center sample among the plural samples. The high-frequency signal components are added to the center sample among the plural samples to generate an addition-resultant signal. A value of the addition-resultant signal is limited to within a range between the upper limit value and the lower limit value.

Abstract: A method and arrangement for steepening the edges of a color signal, in which a control signal is generated which is obtained by differentiation, rectification and subsequent differentiation of the rectified first differentiation, and is temporarily assigned to the color signal, and in which, in dependence upon the control signal, chrominance values of reference pixels of the color signal are copied on edge pixels of the color signal in such a way that the chrominance values of reference pixels preceding the edge pixels are copied on the edge pixels in the case of a positive control signal and the chrominance values of reference pixels following the edge pixels are copied on the edge pixels in the case of a negative control signal, false chrominance values of pulses which are steepened are prevented in that a chrominance value of a reference pixel is copied on an edge pixel only when the values of the control signal in the assigned region between the reference pixel and the edge pixel do not have a zero cross

Abstract: Digital image enhancement apparatus for processing an input sampled image signal having an input sample rate to generate an output, enhanced, image signal at the input sample rate comprises one or more filters for filtering and sample rate up-converting the input image signal to generate a detail signal at an intermediate sample rate higher than the input sample rate and for generating an intermediate image signal, the intermediate image signal being a sample rate up-converted version of the input image signal; a detecting circuit for detecting whether a combination of the detail signal and the intermediate image signal goes beyond predefined limits on the signal level of the output image signal and, if so, for modifying the detail signal so that a combination of the detail signal and the intermediate image signal would not go beyond the predefined limits on the signal level of the output image signal; a sample rate down-converter for converting the detail signal to a down-converted detail signal at the input

Abstract: Video camera which emphasizes an outline of a video signal produced thereby. A detail signal of a video image represented by the video signal is generated and which represents a vertical outline emphasis signal. Edges of the video image and burst-like portions of the video signal are detected, and an edge detection signal is generated that corresponds in one manner to the detected edges and that corresponds in another manner to the detected burst portions. The detail signal is adjusted by the edge detection signal or by a cross color suppression signal generated from the vertical outline emphasis signal. The video signal then is modified by the adjusted detail signal so as to produce the outline emphasized video signal. The detail signal may also be adjusted by a gain setting signal that corresponds to the vertical outline emphasis signal and which is compressed in level when the vertical outline emphasis signal is relatively low.

Abstract: The present invention relates to a multi-frequency display system and method for providing sharpness enhancement. The system comprises a sharpness enhancement circuit that is configured to receive a first and a second input video signal, where the first input video signal operates at a first frequency, and the second input video signal operates at a second frequency. The system further comprises a controller circuit coupled to the sharpness enhancement circuit, that is configured to generate a first sharpness enhancement signal corresponding to the first frequency and a second sharpness enhancement signal corresponding to the second frequency. The sharpness enhancement circuit generates a first control signal in response to the first input video signal and the first enhancement signal, and the sharpness enhancement circuit generates a second control signal based on the second input video signal and the second enhancement signal.

Abstract: In a method of obtaining an improved perceived color transient, an artificial transient signal is inserted (50) into a luminance signal (Yin) when it is detected (10, 20, 30) that there is an edge in a chrominance signal (Cin) in the absence of an edge in the luminance signal (Yin).

Abstract: An improved circuit for compensating a pattern recognition type edge for a video signal processor which is capable of preventing a undershooting and an overshooting by recognizing a pattern of a luminance signal which is converted into a digital form when compensating an edge of a luminance signal, by substituting a sample value at incline start or end portions and at decline start or end portions of a pattern with the previous sample value or the next sample value, by generating a plurality of luminance signals having a different delay time by sequentially delaying a luminance signal which is converted into a digital form as many as the number of samples, by subtracting a luminance signal which is delayed by the previous process from the luminance signal which is delayed by each process, by recognizing a pattern of an edge of luminance signal by logically operating a difference signal and a reference signal after computing a plurality of difference signals, and by selecting a signal among luminance signals h

Abstract: An improved interpolation method in which a threshold value used for determining a pixel value of a pixel generated by interpolation according to a context which is a state value of adjacent pixels. In the interpolation method, the ambiguity between the interpolation value and the threshold value is removed by using the context, thereby reducing the blocking and smoothing phenomena in the restored binary image.

Abstract: An improved interpolation method in which a threshold value used for determining a pixel value of a pixel generated by interpolation according to a context which is a state value of adjacent pixels. In the interpolation method, the ambiguity between the interpolation value and the threshold value is removed by using the context, thereby reducing the blocking and smoothing phenomena in the restored binary image.

Abstract: An image processing apparatus and method wherein the apparatus has an input unit for inputting input image information of image data and output device information of an output device which outputs the image data and an image processing unit for subjecting the image data to an aperture correction process in accordance with the input image information and output device information.

Abstract: A current pixel of a video image is adaptively filtered to provide stronger filtering when there is a high likelihood that noise is present. Weaker filtering is provided when the presence of a color and/or brightness edge is likely in the video image. Each pixel has luminance and chrominance amplitude values. In a filtering method, a current pixel is intermediate to first and second pixels in the video frame. Difference signals are determined based on the amplitude difference between the current pixel and first and second adjacent pixels. A plurality of available filters provide successively stronger filtering of the current pixel amplitude. One of the filters is selected for filtering the current pixel according to the difference signals. Secondary difference signals which indicate the amplitude difference between the current pixel and pixels which are adjacent to the first and second pixels are also considered in the selection process.

Abstract: An apparatus for processing a video signal by adjusting the contour of a picture. The apparatus includes an arrangement from a delay circuit 2 to a subtraction circuit 5 for extracting a contour of the picture and generating at least a signal opposite in polarity to a contour enhancement signal enhancing the extracted contour. The signal polarity is continuously varied from a maximum value of a positive polarity to a maximum value of an opposite polarity by a variable resistor RV2, an output of which is added to the input video signal by an addition circuit 6. With the processing apparatus, a picture can not only be raised in resolution as felt by the viewer, that is can be enhanced in contour, but also can be lowered in resolution as felt by the user, that is can be softened in contour. A corresponding method for processing a video signal by adjusting the contour of a picture and a video camera having the apparatus for processing the video signal in this manner are also disclosed.

Abstract: In a video display terminal (VDT) adapter connected to a moving picture output device, inputting means inputs, from the moving picture output device, an input moving picture signal indicative of input moving pictures having brightness which changes drastically. Connected to the inputting means, picture temporal frequency attenuator means selectively attenuates a particular frequency band of the input moving picture signal to produce a smoothly-changing moving picture signal indicative of smoothly-changing moving pictures. The particular frequency band includes human sensitive frequency components. Connected to the picture temporal frequency attenuator means, outputting means outputs the smoothly-changing moving picture signal as an output moving picture signal. The particular frequency band may lie on a range not less than 7 Hz.

Abstract: (1) The analog or digital components (such as RGB, Y/I/Q, Y/U/V, Y/R-Y/B-Y, Y/Cr/Cb, etc.

Abstract: A video display monitor employs interpolation which maintains sharpness in images which have large differences in signal levels of picture elements and assuring smoothness of images such as lamps which have small differences in signal levels. The difference in the signal level differences of respective adjacent picture elements is detected by delay and subtraction. A decoder produces a signal for interpolation based on the input of an interpolation coefficient and the absolute value of the interpolation coefficient which is output from an absolute value detector.

Abstract: A circuit for enhancing chrominance transitions in a received chrominance video signal comprises a linear-phase digital filter supplied with an input stream of discrete chromatic image elements. The filter also has a high-pass transfer characteristic in a region of the frequency spectrum corresponding to an upper limit of a transmitted chrominance signal bandwidth for enhancing high-frequency components of the received chrominance signal. The circuit additionally includes non-linear digital post-processing circuitry which accepts as input an output of the filter and the input stream of discrete chromatic image elements. The non-linear post-processing circuitry acts on the output of the filter to eliminate distortions introduced in the received chrominance signal by the filter. The post-processing circuitry then detects if the received chrominance signal contains a transition pattern corresponding to predetermined patterns.

Abstract: A digital color transient improvement (CTI) method and apparatus for enhancing the color sharpness of a chrominance signal by increasing the steepness of color edges without ringing. A median logic circuit (30) samples three signals A, B and C, and selects values from these three signals to provide an output signal that has steep color edges. One signal (A) is the non-processed input signal, a second signal (C) is a twice delayed input signal, and the third signal (B) is the derivative of the once delayed input signal. The present invention is ideally utilized by an SVP and requires a minimum number of instructions, but can also be implemented by a small number of gates on an ASIC or FPGA.

Abstract: A picture signal processing device for processing picture signals for displaying e.g., an enlarged picture, a contracted picture or a still picture. The picture signal processing device includes a motion detection unit for comparing the picture signal level of a pixel under detection in a first field or a second field together making up a frame, the picture signal levels of pixels lying close to the pixel under detection and the value of a variably set motion detection coefficient to one another for detecting the possible presence of motion in the picture of the pixel under detection. The first field is formed by every two scanning lines and the second field is formed by the remaining scanning lines.

Abstract: A video camera and an image enhancing apparatus which can add details without deteriorating an S/N ratio near the black level are provided. The video camera is constructed by: an image pickup device for photographing an object and generating a video signal; a signal level detecting circuit for detecting a signal level of DC components of the video signal; a detail signal forming circuit for forming a detail signal to correct an outline of an image which is expressed by the video signal by extracting partial frequency components in the video signal from the video signal; a control unit for controlling the detail signal forming circuit on the basis of an output of the signal level detecting circuit in a manner such that as a signal level of the DC components is low, frequency of the detail signal to be formed by the detail signal forming circuit becomes lower; and a mixing circuit for mixing the detail signal to the video signal.

Abstract: A method and apparatus for enhancing an edge in an image edge by controlling the electron beam scanning speed. A primary differential signal is delayed and the delayed and non-delayed signals are fed into a maximum value detection circuit and a minimum value detection circuit. A signal output by the maximum value detection signal, from which a positive alternating current component is removed, and a signal output by the minimum value detection circuit, from which a negative alternating current component is removed, are added together and synthesized. The resultant signal is passed through an amplifier circuit and then across a speed modulation coil of a cathode ray tube.

Abstract: According to an information signal correction processing apparatus of the invention which includes a plurality of clip circuits, a knee circuit, an adder, and a controller, an information signal which has been obtained through the clip circuits by clipping an input information signal in accordance with a plurality of clipping characteristics which have been arbitrarily set and an information signal which has been obtained through the knee circuit by voltage dividing the input information signal in accordance with a voltage dividing ratio which has been arbitrarily set are added by the adder and, when the resultant signal is outputted, the plurality of clipping characteristics and the voltage dividing ratio are respectively controlled by the controller, so that the information signal can be processed without being deteriorated.

Abstract: A method which can be used to enhance an outline of an image displayed in an image display apparatus such as a television receiver, and a circuit performing the method. The circuit includes a peaking signal generation circuit which generates a first peaking signal and a second peaking signal corresponding to an amplitude transition of a video signal. A first peaked video signal generation circuit generates a first peaked video signal by adding the first peaking signal to the video signal. A control signal generation circuit generates a first control signal based on a result of comparing a first-order differential signal developed by differentiating the video signal with a reference signal, and a second control signal by delaying the first control signal for the predetermined period. A first selection circuit selects either the video signal or the first peaked videos signal according to the first control signal.

Abstract: An adaptive anti-flicker data conversion system for converting picture data in a video graphic adapter for displaying on a television. The conversion system reduces flickers adaptively according to the luminance of a pixel and neighboring pixels one line above and below. Contrast difference and mean value are defined based on the luminance of three neighboring pixels. A contrast ratio is computed by dividing the contrast difference by the mean value. Three threshold values are defined for examining the contrast ratio and selecting an appropriate anti-flicker filter. Pixels having higher contrast ratio are processed with filters having stronger anti-flicker effect. The adaptive anti-flicker method reduces flickers without blurring every pixel in the picture data.

Abstract: Disclosed are a display control unit and a control method therefor, for permitting images provided by a plurality of video image sources to overlie, whereby an area of an overlying image plane wherein an original video image source that is composed of lines and shade patterns is displayed by interpolating an original image, and whereby an area wherein an original video image source that is composed of video images is displayed non-interpolated without interpolation. According to the present invention, whether or not the interpolation on image data is required is determined for each pixel by employing a changed value of luminance for each pixel between scan lines, a color difference signal, and color data. Even when a computer image and a video image are displayed on the same screen at the same time, optimal display can be performed on the individual image planes.

Abstract: A video signal processing apparatus includes an equalizer for delaying an input color signal by an adjustable phase retardation. A low pass filter is operative for delaying the input color signal by an adjustable phase retardation. A phase detector is operative for detecting a difference between a phase of an output signal of the equalizer and a phase of an output signal of the low pass filter, and outputting a signal representative of the detected phase difference. The phase retardation provided by the equalizer and the phase retardation provided by the low pass filter are adjusted in response to the output signal of the phase detector to maintain the difference between the phase of the output signal of the equalizer and the phase of the output signal of the low pass filter at a predetermined value, for example, 90 degrees.

Abstract: A circuit for peaking video signals, which can be developed by combining a video signal with a peaking signal having a preshooting and a overshooting potion that are respectively controlled in peaking levels thereof. The circuit includes a delay circuit for delaying a luminance signal for a first predetermined time in order to generate a first delayed signal and for delaying the first delayed signal for a second predetermined time in order to generate a second delayed signal. An adder adds the second delayed signal to a current video signal in order to generate an added signal. A variable amplifying section amplifies the added signal in response to a first control signal from an exterior in order to generate a first variable amplified signal, and amplifies the added signal in response to a second control signal from the exterior in order to generate a second variable amplified signal.

Abstract: A digital filter for noise reduction selects between local variances obtained from adjacent pixels in the same frame and adjacent pixels in the same field. In one embodiment, the digital filter includes a filter modified from an adaptive Wiener filter which preserves edges and smoothes smooth areas of the image. A high compression ratio can be achieved in very smooth regions of the image without introducing artifacts.

Abstract: A video special effect generator comprises a first mixer supplied with an input video signal indicative of an input image, a delay circuit for delaying an output video signal supplied thereto from the first mixer and supplying a delayed output video signal to the first mixer, and a control circuit including an edge detecting circuit for detecting an edge of an input image indicated by the input video signal supplied thereto and outputting an edge signal indicative of the detected edge and generating a mixing ratio control signal on the basis of the edge signal, wherein the first mixer mixes the input video signal and the delayed output video signal supplied thereto from the first delay circuit with a mixing ratio based on the mixing ratio control signal.

Abstract: An electro-optical device and a method for displaying an image are disclosed. A clear image with a clear profile can be displayed therein by processing input image data, for example input image data of TV broadcasting received by the device.

Abstract: An image processing method of the invention is used for dividing each pixel of binary image data into pixels, with of the pixels having a size smaller than each pixel of the binary image data. The image processing method includes the steps of (a) referring to a first white/black pattern formed by a first group of pixels next to a pixel of interest that is a subject of image processing; (b) referring a second white/black pattern formed by a second group of pixels next to the first group of pixels; (c) dividing the pixel of interest into divided pixels; and (d) determining colors of the divided pixels on the basis of the first white/black pattern and/or the second white/black pattern so that an image formed by the divided pixels has a smoothed slant portion or jagged portion.

Abstract: The 25 Hz offset present in the subcarrier frequency of the PAL television standard causes residual and phase modified subcarrier to be left on the luminance signal, which can produce undesirable visual artifacts in the picture. In order to filter luminance therefore without loss of resolution, an adaptive luminance filtering process and structure are provided. Due to the wide range of sample frequencies that must be dealt with, there are e.g. three separate filters available selectable under software control depending on the particular video standard being filtered, i.e. for various of the of NTSC and PAL television standards. The adaptive notch filter is switched on during times of low video transitions and is by-passed during high video transitions, thus avoiding loss of resolution during the high video transitions.

Abstract: A method for displaying an image with a clear outline by correcting original image data of addresses in the vicinity of addresses on which a boundary line image is contained in an original image wherein the addresses on which a boundary line image is contained in an original image have maximal absolute values of gradients of brightness in the original image.

Abstract: An automatic focusing device which uses a video aperture signal in low contrast situations includes an extraction circuit for extracting a signal corresponding to a degree of focus from an input image signal. A focus control circuit is provided for detecting a focus state from the signal extracted from the extraction circuit, and for providing a driving signal for driving a focusing lens on the basis of the results of the detection. A determination circuit is provided for determining whether the image signal has a low contrast. An aperture signal extraction circuit extracts a video aperture signal from the input image signal. Control circuitry is provided for supplying the aperture signal output from the aperture signal extraction circuit to the focus control circuit on the basis of the results of the determination by the determination circuit.

Abstract: A video sharpening circuit for improving video signal detail or providing a unique visual effect extracts the high frequency portion from an input video signal. The high frequency portion is then variably amplified and added to the input video signal or to a reference video signal. The resulting output video signal has the high frequency detail restored to produce an aesthetically pleasing effect.

Abstract: Digital processing apparatus for correcting an image enhancement signal having a shape includes a peak detector for detecting and holding peak levels of the image enhancement signal and an adjustment circuit, responsive to the peak levels, for correcting the image enhancement signal to reduce its peak levels while substantially maintaining its shape and to limit the signal levels of the image enhancement signal to a range of levels substantially between a first predetermined peak limit and a second predetermined peak limit.