Abstract: The values of the primary color space components of an image signal, such as the components of RGB video signal, are maintained within their allowed range by modifying the signal in a different color space, such as YUV space. Specifically, the U and V chrominance components are attenuated by an attenuation factor g while the luminance component Y is not modified. The value of g is the largest possible value less than 1 that will cause all primary color space components that would otherwise be outside the allowed range to be within that range. A high quality of the displayed image is maintained.

Abstract: A video signal processor is provided to receive a luminance signal, a color-difference signal, and a color signal. The processor comprises a circuit for calculating a low-frequency component of the luminance signal, a circuit for calculating a low-frequency component of the color-difference signal, and a circuit for extracting a high-frequency component of the color signal. The processor also comprises a division circuit, a multiplication circuit, and an addition circuit. In the division circuit, the low-frequency component of the color-difference signal is divided by the low-frequency component of the luminance signal, and in the multiplication circuit, an output signal from the division circuit is multiplied by the high-frequency component of the signal extracted, a multiplied signal being outputted as a correction signal for the color signal. In the addition circuit, the correction signal is added to the color signal.

Abstract: A high definition display unit which demodulates, decodes, and processes in relation to chroma and displays a television signal in which a PI (picture) signal and an SI (service information) signal are mixed. A changeover switch 13 connected to an image quality adjusting circuit in a video chroma processing circuit 7 is opened or closed according to an on-off signal S1. showing the superposed period of both signals detected by a decoder 4. If the above on-off signal S1. is on, the changeover switch 13 is opened and the adjustment of image quality is disabled. Therefore, SI display never disappears due to the adjustment of image quality, and the quality of an image can be also adjusted according to an ambient status. Other approaches are also disclosed from preventing image quality adjustment of at least portions of a displayed image containing an information image.

Abstract: A contour correction circuit includes a delay circuit for delaying an input video signal, a corrected waveform generating circuit for generating a contour correction signal out of the input video signal, a variable amplifier for controlling an amplitude of the contour correction signal, a contour control circuit for outputting a gain control signal for controlling a gain in the variable amplifier,. and a first adding circuit for adding an output signal of the delay circuit to an output of the amplifier. When an amplitude-change in an edge portion of the input video signal is over a given level, the smaller amount of contour is corrected at the larger amplitude change. Therefore, even if a signal of a high contrast ratio is adjacent to a signal of a low contrast ratio, desirable contour corrections can be provided to respective signal components.

Abstract: A superior Color Transient Improvement technique is adaptive to the local image features, so that more natural color edge transition improvement can be accomplished. A gain control function is provided that depends on the local image feature so that different regions of the image can be treated differently. Further, a correction signal is controlled in such a way (by the local image feature) that neither undershoot nor overshoot occurs, eliminating the need for post-processing for undershoot/overshoot removal.

Abstract: The invention provides an improved method and system for presenting television signals, including anti-aliasing of text with respect to a background. The background color is determined relatively locally for each element to be anti-aliased, and text or other graphics overlaid on that background are anti-aliased with respect to each relatively local background color. Also, anti-aliasing can be applied to blur text and graphics more vertically than horizontally to reduce flicker, and to blur chrominance more than luminance to reduce cross-chrominance artifacts resulting from Y/C separation. Similar techniques may be used for filtering images in addition to anti-aliasing text characters.

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: In an image enhancement method and circuit, a luminance signal is extracted from input color signals. Histogram equalization is performed using a cumulative density function of the extracted luminance signal which is input in a screen unit. A transform function is controlled to map a mean level of the extracted luminance signal to itself, so that an adjusted luminance signal is output. The color signals are varied according to the variation of the luminance signals to output compensated color signals. Thus, image contrast is enhanced, and an undistorted color signal is provided at the same time. In order to reduce the hardware of the circuit, an interpolated cumulative density function is obtained by interpolating a quantized cumulative density function of an input luminance image and is used as a transform function. The transform function is controlled to map a mean level of the input luminance image to itself.

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: A video frame is decomposed into blocks of pixels. Blocks that contain moving edges are not processed further. The remaining blocks are examined for the likelihood of having color bleeding artifacts, and not processed further if the likelihood is low. The likelihood is determined by examining statistics of the chrominance values. The remaining blocks are de-color bleeding filtered at the chrominance plane, without affecting the corresponding luminance plane.

Abstract: Pixels in a video image may be segmented based upon selected criteria, such as a common color, texture, shape, amplitude range or temporal variation. Color values for these pixels may be used to calculate a color probability function which indicates the probability that the color value of the pixel will lie within a designated range of values. The pixels are also used to calculate a texture probability function that indicates whether the pixel represents a designated texture. Pixels that are assigned to a given segment may then be further processed to improve the quality of an image. In this manner, pixels that identify grass, sky, human skin, etc. may be identified and processed in order to achieve a more pleasing appearance.

Abstract: There is disclosed an apparatus for performing segmentation-based enhancements of a video image. The apparatus comprises: 1) an input buffer for storing video frames of an incoming video signal; 2) a segmentation controller capable of segmenting a first stored frame into a plurality of segments, each of the plurality of segments comprising a plurality of pixels having at least one common property; 3) an image processor capable of calculating a probability function associated with at least one pixel in the first stored frame, the probability function indicating a probability that the at least one pixel belongs within a first selected one of the plurality of segments; and 4) an enhancement controller capable of enhancing a parameter of the at least one pixel as a function of the probability function of the at least one pixel.

Abstract: A contour emphasizing circuit is provided with a number-of-pixels changing circuit (37) which changes the numbers of pixels of digital R, G, and B signals, a gamma correction circuit (39) which performs gamma correction on the output of the circuit (37), a Y-signal generating circuit (36) which generates luminance signals from the output of the circuit (37), an contour extracting circuit (38) which extracts contour components from the output of the circuit (36), a coefficient multiplying circuit (42) which outputs contour components for R, G, and B by multiplying the extracted contour components by coefficients Kr, Kg and kb contour adding circuit (34r), (34g), and (34b) which respectively add the outputs of the circuit (39 and 42). Thus, the contour emphasizing circuit performs contour emphasis on the digital R, G, and B signals.

Abstract: An edge achromatization circuit and method is disclosed wherein, in digital camera signal processing, a signal having a linear characteristic before &ggr; correction is performed to suppress a color component of an edge portion while keeping a luminance. The edge achromatization circuit includes a luminance signal operation matrix circuit for converting R, G, B signals before &ggr; correction is performed therefor into a luminance signal, an edge detection circuit for extracting an edge signal from the luminance signal, an absolute value operation circuit for converting the edge signal into an absolute value, a multiplier for controlling the gain of the absolute value, subtractors for obtaining color difference signals from the R, G, B signals and the luminance signal, multipliers for multiplying the color difference signals and an output coefficient, and subtractors for arithmetically operating results of the multiplication and the R, G, B signals to obtain R′, G′, B′ color signals.

Abstract: A method for image enhancement for an interlaced display includes receiving a first group of pixels aligned about an axis, detecting a second group of pixels within the first group of pixels, each pixel of the second group of pixels having a luminous disparity between adjacent pixels less than a first threshold, determining whether each pixel within the second group of pixels is part of a line or edge, the determination including a comparison of luma or chroma disparities between neighboring pixels and filtering each pixel determined to be part of a line or edge.

Abstract: In a signal processing apparatus for processing an image signal, a hue difference between adjoining pixels is detected by a color image edge detector, and an aperture control main gain circuit amplifies a luminance signal using a gain determined on the basis of the hue difference detected by the color image edge detector to enhance an edge pixel of an image.

Abstract: Techniques for enhancing edges in video signals while reducing the amounts of undershoots and overshoots. A video signal is processed to generate a first signal indicative of detected edges in the video signal. The first signal can be generated by lowpass filtering the video signal to generate a lowpass signal and subtracting the lowpass signal from a luminance signal that has been extracted from the video signal. The first signal is then processed with a “non-linear” transfer function to generate a second signal having enhanced edges. The second signal is used as the correction or enhancement signal, and is added to the lowpass signal to provide an output signal having enhanced edges with reduced or minimal amounts of undershoots and overshoots.

Abstract: An objectionable outlining effect, seen as dark edges and white edges outlining everything in a scene, is eliminated by clipping or limiting the spikes generated by excessive enhancement. Specifically, a method is used for improving the quality of an enhanced video image, while simultaneously maintaining or improving image sharpness, by clipping the RGB levels of the enhanced video image, at the points of enhancement, to upper and lower level bounds representing the signal levels of the video signal prior to its enhancement.

Abstract: A contour emphasizing circuit has a Y-signal generator (36) which generates a luminance signal from digital R, G and B signals, a contour extracting circuit (38) which extracts contour component from the generated Y signal, a factor multiplier (42) which multiplies the contour component by factors Kr, Kg and Kb and outputs contour components for R, G and B and contour adders (34r, 34g and 34b) which add the contour components for R, G and B to the R, G and B signals respectively and which emphasizes the contour for the digital R, G and B signals.

Abstract: An image processing system including a display output processor using Temporal Gamma Processing (TGP) and Reverse Super-resolution (RSR) techniques to process images. TGP assures that the time-related representation of an image is as accurate as possible, and thus, based on a previous frame value and a known transfer function of the display modulation system, adjusts its output values to provide a desired output value during display of a desired frame. RSR performs a superset of the frame rate conversion process for converting between disparate input and output frame rates. RSR, improving display quality when intended display images have apparent resolution higher than can be supported by an image modulator, sequences lower resolution images at higher frame rates to simulate higher resolution outputs.

Abstract: Since A/D conversion circuits 30r, 30g and 30b to convert for output analog R, G and B signals to digital signals, a phase adjustment circuit 31 to output by delaying in the portion of 1 linc output signals of these A/D conversion circuits 30r, 30g and 30b, a first signal generation circuit 35 to generate Y signals from output signals of A/D conversion circuits 30r, 30g and 30b, a second Y signal generation circuit 37 to generate a Y signal from an output signal of the phase adjustment circuit 31, a contour extracting circuit 39 to extract a vertical contour component and a horizontal contour component from Y signals generated by first and second Y signal generation circuits, and contour adders 34r, 34g and 34b to output signals contour-emphasized adding a vertical contour component and a horizontal contour component extracted by this contour extracting circuit 39 to output signals of the phase adjustment circuit are provided, and since it has been designed that the contour extracting 39 extracts a vertical c

Abstract: A method and apparatus for electronically processing video signals representing images of an object or scene so that details of some portion or all of the object or scene are enhanced in the video display reproduction of the images. Video image signals from a video camera are processed to derive digital color-representative signals and a digital luminance signal, and the luminance signal is filtered to remove higher spatial frequency components. The resulting low pass digital data is subtracted from the original luminance image data, leaving digital data representing the high-pass image components. The high-pass image digital data is passed to an amplification stage where all or only selected pixels are amplified by a factor that varies as a function of the low-pass data value of those pixels and by the location of the pixels within the image. This enables different degrees of enhancement of the light and dark areas of the image.

Abstract: A contour emphasizing circuit is provided with a Y-signal generating circuit (36) which generates luminance signals from digital R, G, and B signals, a contour extracting circuit (38) which extracts contour components from the generated Y-signal, a coefficient multiplying circuit (42) which outputs contour components for R, G, and B by multiplying the extracted contour components by coefficients Kr, Kg, and Kb, addition circuits (34r, 34g, and 34b), and a contour emphasis enabling circuit (39) which controls the period for which contour components extracted by the extracting circuit (38) arc supplied. Therefore, the contour emphasizing circuit prevents process errors in the peripheral portion of the screen of a display.

Abstract: Dithering logic includes a number of programmable linear feedback shift registers (LFSRs), each configured to receive one of a number of color components (e.g., red-green-blue) of a video information signal as an input and to provide one of a number of dithered color components of the video information signal as an output. The dithered color components each include a greater number of bits than the color components. The LFSRs may be configured so that each LFSR includes a mask register configured to accept a characteristic polynomial. The dithering logic may be included in a set-top controller of a computer network that is organized to include a graphics processor communicatively coupled to the set-top controller. The dithering logic is thus configured to introduce pseudorandom noise into video information signals transmitted from the graphics processor to the set-top controller in accordance with one or more characteristic polynomials. Preferably, the characteristic polynomials are primitive polynomials.

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: 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: This invention relates to the color matching function used in connection with the luminance or white stretch function in a television video processor. Automatic adjustment in the amplitude of the color difference signals is provided to compensate for the effect of the stretch of the luminance signal in a provision called color matching. The general principal of color matching being, any percentage change in the amplitude of the luminance signal due to the white stretch effect, must be balanced by the same percentage changes in the color difference signal so that the ratio of the color signals can be maintained after matrixing. This accomplished by compensating the color difference signals by a varying amount that decreases with increasing the input luminance signal level when the level of the input luminance signal is above said selected threshold.

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 image quality correction circuit having a variable gain amplifier for amplifying an extracted high-frequency component of a luminance signal in such a manner that the gain thereof is increased when detected color density is high, and is reduced when the detected color density is low, and a slice circuit for slicing the outputted amplitude of the variable gain amplifier at a prescribed value, wherein a corrected luminance signal is obtained by combining an image quality correction signal outputted from the slice circuit with the luminance signal to be corrected.

Abstract: An S/N ratio is improved and flicker noises and mosquito noises are suppressed while deterioration of a resolution is suppressed. A three-dimensional cyclical digital filter (16) is interposed between a MPEG video decoder (12) and a video DAC. In accordance with a luminance input signal Yu from the MPEG video decoder (12), Yv is calculated from the following equation.Yv=Ft-K.multidot.(Ft-F(t-1))where K is a value in the range of 0.ltoreq.K<1, Ft is a present Yu input value, and F(t-1) is a one-frame preceding Yv.

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: 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: An image data modification technique addresses certain image defects characteristic of still images derived from original video sources, such as television or videotape. Color bleeding, caused by an inability of chrominance signals to change from pixel to pixel as quickly as luminance signals, is addressed by processing the chrominance signal to have slopes closer to a change in the luminance signal for the same small area of the image. The technique can be employed on the image data for a single frame of video image, and does not require information from previous or subsequent frames.

Abstract: An image quality correction circuit having a variable gain amplifier for amplifying an extracted high-frequency component of a luminance signal in such a manner that the gain thereof is increased when detected color density is high, and is reduced when the detected color density is low, and a slice circuit for slicing the outputted amplitude of the variable gain amplifier at a prescribed value, wherein a corrected luminance signal is obtained by combining an image quality correction signal outputted from the slice circuit with the luminance signal to be corrected.

Abstract: An image quality correction circuit having a variable gain amplifier for amplifying an extracted high-frequency component of a luminance signal in such a manner that the gain thereof is increased when detected color density is high, and is reduced when the detected color density is low, and a slice circuit for slicing the outputted amplitude of the variable gain amplifier at a prescribed value, wherein a corrected luminance signal is obtained by combining an image quality correction signal outputted from the slice circuit with the luminance signal to be corrected.

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 image quality correction circuit having a variable gain amplifier for amplifying an extracted high-frequency component of a luminance signal in such a manner that the gain thereof is increased when detected color density is high, and is reduced when the detected color density is low, and a slice circuit for slicing the outputted amplitude of the variable gain amplifier at a prescribed value, wherein a corrected luminance signal is obtained by combining an image quality correction signal outputted from the slice circuit with the luminance signal to be corrected.

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: A device for processing video signals includes a noise reduction arrangement and a contour correction arrangement. To improve color correction, a color correction arrangement (11) is arranged between the noise reduction arrangement (10) and the contour correction arrangement (12).

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: An image quality correction circuit having a variable gain amplifier for amplifying an extracted high-frequency component of a luminance signal in such a mariner that the gain thereof is increased when detected color density is high, and is reduced when the detected color density is low, and a slice circuit for slicing the outputted amplitude of the variable gain amplifier at a prescribed value, wherein a corrected luminance signal is obtained by combining an image quality correction signal outputted from the slice circuit with the luminance signal to be corrected.

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: A color conversion function is corrected in accordance with the input color data (Xin, Yin, Zin) of the original image. The original image is therefore converted into colors which are different from colors of the original image but which are appreciated by the user. One or more specific color is previously determined. The appropriate color value memory 40 stores appropriate output values (Xbesti, Ybesti, Zbesti) for the specific colors. The color value discrimination portion 20 judges whether or not the input color data (Xin, Yin, Zin) is the specific color. When the input color data (Xin, Yin, Zin) is judged as the specific color, the corrected characteristic value calculation portion 24 calculates a correction characteristic value (dXi, dYi, dZi) based on the input color data (Xin, Yin, Zin) and the appropriate calor value.

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: 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: 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: A video signal regenerator in color television comprises two video signal regeneration channels each of which has a video signal front detector (5-7) electrically connected to a driving input of a video holding sampler (1-3), while the third video signal regeneration channel has an input receiving a video signal of a pass-band wider than that of other video signals, which channel being analogous to the other regeneration channels and also comprising a video signal front detector (5-7) electrically connected to the driving input of the video holding sampler (1-3).

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.

Abstract: An automatic aspect ratio discrimination apparatus for detecting a picture starting position, a picture ending position and a subtitle ending position by generating three histograms segmented by two slice levels S and T at every line from a luminance signal Y at a comparison circuit and counters, judging when the line is black, a picture or a subtitle by inputting the obtained histograms to the comparison circuit, detecting lines varying from black to picture, from picture to black, and from subtitle to black at an edge detection circuit and judging if the lines varying from black to picture and from picture to black are stable in time or not at a temporal filter.