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: A picture signal processing method and apparatus in which the block distortion or the mosquito noise generated on picture compression/expansion using block encoding or the like is removed and picture quality correction such as contour enhancement is carried out effectively. Compression-encoded picture signals are expanded and decoded by a MPEG decoder 106 and the decoded picture signals are sent to a noise reducing circuit 107. The noise reducing circuit 107 reduces the noise by block distortion reduction or by field recursive type noise reduction. The resulting noise-reduced or noise-freed picture signals are sent to a picture quality correction circuit 108, which then performs picture quality correction, such as contour enhancement.

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: A contour enhancement method and circuit for adaptively enhancing a contour component of a luminance signal. In the method, a coring operation is performed with respect to the contour component. For the coring operation, a coring value is used which is adjusted according to characteristics of the contour component detected from an input luminance signal. The cored contour component is amplified by a predetermined gain, and the level of the gain-controlled contour component is limited to a predetermined threshold value to output a level-limited contour component. The level-limited contour component is then added to the input luminance signal to become a contour-enhanced luminance signal.

Abstract: A method and apparatus for enhancing decoded images which have been encoded checks the neighboring picture elements of a picture element which are located in the region of the picture element to see whether the brightness values and/or the color values of the neighboring picture elements is similar enough to brightness values and/or color values of the picture element in question according to a similarity criterion such as a threshold. When the similarity is within the threshold, then the corresponding neighboring picture element is taken into consideration in determining a new brightness value for the picture element in question. Neighboring picture elements are taken into consideration when the neighboring picture element and the picture element are located in different image blocks of the image which has been decoded from a block-based encoding process.

Abstract: A noise reduction method and circuit determines the presence of an impulse component in a current input sample by generating two windows of different size and detecting the impulse component in the two respective windows in order to prevent degradation of an input image signal due to an erroneous detection. If the impulse component is not detected in the sample, the sample is bypassed. However, if the impulse component is detected, the sample is trimmed by a trimmed mean filter and then output.

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: Video signal processing apparatus includes a picture enhancement processor for processing a video signal to produce an enhanced video signal. The video signal includes a signal component representing video image data and another signal component representing non-image data such as vertical sync and a binary information component. The binary information component represents binary information that may occur, for example, during vertical blanking such as closed caption data, content advisory information (V-chip), or extended data services information. A control unit modifies the enhancement performed by the picture enhancement processor during intervals of the video signal that include non-image information. Modifying enhancement processing (e.g., reducing or disabling) during intervals that include the non-image information reduces degradation of the non-image information caused by the enhancement processing.

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: A video signal processing circuit for processing a video signal including a noise is disclosed which comprises: an edge enhancement signal generation circuit for generating an edge enhancement signal from the video signal; a noise reduction circuit for reducing a level of the noise to generate a noise reduced video signal; and an adder for adding the edge enhancement signal to the noise reduction video signal to output a processed video signal. The apparatus may further comprise an input terminal for receiving the video signal, wherein the edge enhancement signal generation circuit and the noise reduction circuit coupled to the input terminal are in parallel.

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 post-processor for a decoded video sequence includes a digital noise reduction unit and an artifact reduction unit which significantly reduce blocking artifacts and mosquito noise in a video image. The post-processor uses both temporal and edge characteristics of the video image to enhance the displayed image. A coding parameter from a decoder is used in a coding parameter adaptive filter unit within an artifact unit to further enhance the perceived quality of the displayed image. The coding parameter for a particular macroblock is selected using a characteristic of that macroblock. The post-processor operates on a current frame of pixel data using information from the immediately preceding post-processed frame that is stored in a frame memory of the post-processor. The post-processor uses artifact reduction only on portions of the image that are not part of an edge, and are not part of a texture or fine detail area.

Abstract: A post-processor for a decoded video sequence includes a digital noise reduction unit and an artifact reduction unit which significantly reduce blocking artifacts and mosquito noise in a video image. The post-processor uses both temporal and edge characteristics of the video image to enhance the displayed image. The post-processor operates on a current frame of pixel data using information from the immediately preceding post-processed frame that is stored in a frame memory of the post-processor. The post-processor first identifies texture and fine detail areas in the image. The post-processor uses artifact reduction only on portions of the image that are not part of an edge, and are not part of a texture or fine detail area. Since artifact reduction is not utilized on these areas, the post-processed image is not softened in regions where it is easily noticed by the human eye.

Abstract: In an image processing apparatus, a uniform region whose luminance level change is small is correctly extracted from a noise-containing image. To this end, this image processing apparatus includes an extracting module for extracting a high frequency component of a luminous signal of the image over an entire portion of the image within one screen; histogram generating module for generating a histogram of a luminance level of the luminance signal for one screen on the basis of the output value of the extracting module; coefficient calculating module for analyzing the histogram to calculate a predetermined coefficient indicative of likeness of the uniform region every luminance level; and pixel-position-depending coefficient producing module for establishing a correspondence relationship between the predetermined coefficient calculated by the coefficient calculating module and all of the pixel positions on the image in correspondence to the luminous level of the luminance signal from each of the pixel positions.

Abstract: A picture definition apparatus for video display equipment comprising a first filtering circuit for extracting a high-frequency component from an input video signal, an amplifier for amplifying an output signal from the first filtering circuit, a first delay circuit for delaying the input video signal to match it with an output signal from the amplifier, and an adder for adding an output signal from the first delay circuit to the output signal from the amplifier.

Abstract: Both a sharp print image and a natural reproduced move image can be obtained from a signal recorded on a recording medium. A recording signal, read from the recording medium, is converted into digital data and is delayed by one field. Data representing the current image in the n-th field and data representing an image in the (n-1)-th field one field ahead of the current image, are applied to a subtracting circuit, to extract a component representing moving image portions. An interpolated image for making movement correction is created from the extracted component representing the moving image portions by an interpolating circuit. Data representing the interpolated image and the data representing the current image in the n-th field are synthesized by a synthesizing circuit, to output composite data as data representing an image which has been subjected to movement correction.

Abstract: An apparatus for cancelling noise and improving details of color components of an image by processing a color component value corresponding to a respective pixel, including a high-frequency component detector for individually detecting a high-frequency color component value contained in the color component value corresponding to the respective pixel, a noise detector for receiving the high-frequency color component value detected by the high-frequency component detector, judging whether a noise component is contained in a corresponding pixel and outputting a first binary signal indicative of a judgement result, a storage unit for outputting a value designated by the detected high-frequency color component value and the first binary signal among detail improved values and noise cancelled values both of which are pre-stored therein, and an adder for individually adding the value output from the storage unit and the corresponding color component value.

Abstract: A filter acting on digital image signals for apparatus of the video type includes at least first and second processing units adapted to elect an image edge, each processing unit includes an inferential circuit operating on fuzzy logic, which has first and second input terminals and an output terminal, and first and second comparison elements each having first and second input terminals and an output terminal, the input terminals being intended for receiving discrete digital signals of an image. The output terminals of the first and second comparison elements in the first processing unit are respectively connected to the first and second input terminals of the inferential circuit included in the first processing unit, and the output terminals of the first and second comparison elements in the second processing unit are respectively connected to the first and second input terminals of the inferential circuit included in the second processing unit.

Abstract: A television apparatus with a built-in optical disk device for reproducing a video signal recorded on an optical disk to make a display. By disposing the optical disk device apart from the high voltage generating section of the television apparatus and an anode electrode of a cathode-ray tube and shielding the optical disk device, influence of dust and noise is reduced. Simultaneously, by reading out a video signal and information concerning the video signal, and optimally controlling video display of the video signal, setting is conducted so as to make flicker at the time of still picture display and block noise and mosquito noise at the time of motion picture display inconspicuous. Video images supplied from the optical disk are thus displayed with a satisfactory quality.

Abstract: In video signal processing circuitry detail enhancement is done on each of three color channels in response to the detail information, the enhancement of the detail in each color channel being done in reliance on separated high-spatial-frequency information originally contained in that channel, as long as it is sufficiently greater in amplitude than a reference level somewhat above that expected for thermal noise. When the amplitude of the detail information originally contained in a channel is insufficiently above that reference level, the thermal noise is suppressed by subtracting the separated high-spatial-frequency information therefrom. The same filter arrangements are used to separate high-spatial-frequency information for suppressing thermal noise in each color channel as for enhancing the detail in each color channel.

Abstract: A video processor, having an input and an output, for compensating for accumulated phase and amplitude errors encountered during transmission of a video signal over a communications channel. The video processor includes a high-pass filter and amplifier, coupled to the input; a post-correction-phase-and-gain restorer; a wide-band-video-delay line coupled to the input; a pre-correction-comb-equalizer restorer; and a combining network, coupled to the output. The high-pass filter has a bandwidth characteristic which is approximately inverse to a low-pass characteristic encountered by the video signal during its transmission over the communications channel. The high-pass filter takes the video signal and outputs a filtered-video signal. The amplifier associated with the high-pass filter inverts the filtered-video signal. The post-correction-phase-and-gain restorer adjusts the inverted-filtered-video signal to generate a restored-video signal.

Abstract: A method for processing video data to produce a progressively scanned signal from an input of conventional interlaced video. The data is received at a processor (1), used to determine a motion signal (26) over time between field of the data. The motion signal is filtered to reduce errors caused by noise-corrupted video sources and then further filtered to spread out the determined motion signal. Edge information (30) is located and combined with the motion signal to produce an integrated progressive-scan signal (36) for display on a video display device, producing images with sharper edges and motion signals which have a lower susceptibility to noise.

Abstract: A method of improving the sharpness of horizontal edges of an image that has been vertically scaled. The scaled signal, which represents a series of pixel values, is used to derive an aperture correction value (41-46), which is determined by the scaling ratio and an edge factor. This aperture correction value is added to the scaled signal (47), resulting in enhanced pixel values at edges.

Abstract: A method and apparatus which allows different amounts of filtering to be applied to specific parts of a foreground image, thus minimizing visible noise in the backing area, while preserving fine detail information of foreground objects. The method and apparatus identify three areas within the foreground, namely unobscured backing (screen) area, screen to foreground subject transition area, foreground subject area. The area where full amount of filtering is desired is the backing area, including shadows. This is the area where the background image will be added, and if noise is present in this area, it will be added to the background image. The transition area from the screen to the foreground object requires variable amounts of filtering, depending on the width of the transition. For sharply focused edges and very fine detail, the transition width is very small, and any filtering applied there will cause blurring and softening of these edges and details. Therefore, no filtering is applied to those areas.

Abstract: A method for processing video data to produce a progressively scanned signal from an input of conventional interlaced video. The data is received at a processor (1), used to determine a motion signal (26) over time between field of the data. The motion signal is filtered to reduce errors caused by noise-corrupted video sources and then further filtered to spread out the determined motion signal. Edge information (30) is located and combined with the motion signal to produce an integrated progressive-scan signal (36) for display on a video display device, producing images with sharper edges and motion signals which have a lower susceptibility to noise.

Abstract: A 3D nonlinear postprocessing system and method are utilized to reduce coding artifacts produced by block-based motion-compensated transform coding. In the system and method, a separable 3D filtering structure is used: space-variant FIR-Median Hybrid filtering is used in spatial domain, followed by a motion-compensated nonlinear filtering in the temporal domain. By using this structure and method, the coding artifacts in a reconstructed image sequence can be effectively reduced without blurring edges or moving objects in the image sequence. Significant improvement in the picture quality of low bit-rate coded video sequences is thereby achieved.

Abstract: The present invention is a motion adaptive spatial filtering(MASF) method for use with a image coding apparatus, which proceeds the temporal band-limitation of the video frame signals on spatial domain along the trajectory of a moving component without temporal aliasing by using a filter having a band-limitation characteristic according to a cutoff frequency. It is well known that video signal may contain a lot of temporal aliasing components because of insufficient frame sampling rate. And it is impossible to design band-limiting temporal filter simply by convolving a sequence of frames along the temporal direction. From a signal processing point of view, the aliasing degrades filter characteristics. This filtering method takes advantage of the fact that, if motion of each pixel is known, the temporal filtering can be performed in the spatial domain filtering along its trajectory. That results in de-aliasing characteristic.

Abstract: An interlacing television camera apparatus includes a solid-state imaging device, drive unit, delay unit, and vertical-edge correcting unit. The drive unit drives the imaging unit to simultaneously output, in a first field, a main video signal and a sub-video signal i.e., even and odd numbered lines, respectively, in a first field from the device, which represent a charge accumulated in a pixel located on a scanning line of the first field and a charge accumulated in a pixel located on a scanning line of a second field next to the first field, respectively. Next, the drive unit drives the imaging device to simultaneously output, in the second field, a main video signal and a sub-video signal in a second field from the device, which represent the charge accumulated in the pixel located on the scanning line of the second field and a charge accumulated in a pixel located on a scanning line of a first field next to the second field, respectively.

Abstract: A method is provided for image processing to remove noise and improve smoothing of nonimpulsive noise while preserving major identifying edges of the image, all of which are accomplished corresponding to a prescribed scale of interest. The method achieves nonlinear cluster filtering relying upon a maximum entropy principle. A single scale parameter governs filtering by dictating the spatial extent of neighboring data used for clustering. This, together with the signal characteristic (e.g., variation in gray scale) determines the scale parameter in the output space. The described method is unsupervised and data driven.

Abstract: An apparatus and a method for enhancing a transient edge of a video signal.

Abstract: A two-dimensional noise shaping filter circuit including a first adder for adding a feedback signal to the input signal A quantizer is provided for quantizing an output from the first adder. A second adder adds an output from the quantizer to the output from the first adder. A transfer function unit provides an output from the second adder with a two-dimensional transfer function so as to generate the feedback signal to be supplied to the first adder. Using the noise shaping filter circuit, it becomes possible to provide a video signal with a two-dimensional noise shaping process, not only for a present line but also for a preceding line and a succeeding line. White noises caused by the quantizing process can be moved towards corners of a square Brillouin zone. Noise levels can be decreased at desired locations, such as at a portion of the center of a screen having a lower spatial frequency.

Abstract: A multilevel nonlinear filter in a HD-MAC decoder, for performing intra-frame filtering corresponding to a post processing, and for performing a progressive scan conversion using edge information includes a delay unit for delaying an input image signal and providing both 1H- and 2H-delayed signals, an edge level estimation signal generating unit for generating first and second window mask data from the input image signal and the delayed signals, and performing a high-speed bubble sort for the generated first and second window mask data, thereby providing first and second estimation signals, an absolute difference signal generating unit for generating an absolute difference signal, an edge detection unit for comparing the output absolute difference signal with a predetermined threshold value, thereby producing edge detection information on a current pixel, and a noise suppression unit for median-filtering the first and second estimation signals and the information on the current pixel in case of edge detection

Abstract: A noise component of a video signal is reduced by using a three dimensional discrete cosign transform (3-D DCT) to determine the time frequency spectrum of both the video signal and the noise component, subtracting the time frequency spectrum of the noise component from the time frequency spectrum of the video signal, and converting the time frequency spectrum of the modified video signal back to the spatial time domain by using an inverse 3-D DCT.

Abstract: A video data splitting circuit is disclosed, and the circuit includes a control part and a signal holding and outputting part. The control part includes a sequential address generator, a random address generator, a first selector, an inverter, and a second selector. The signal holding and outputting part includes a first latch, a first memory, a second latch, a third latch, a second memory and a third selector. According to the present invention, the noises added to the transmitting signals are dispersed, so that the final picture at the receiving end should not be affected by the noises.

Abstract: In a video signal processing apparatus for restoring a signal which has been bandwidth-compressed by offset sub-sampling after restoring an image from sample points of a same field of a sub-sampled signal, a first adder performs an inter-field averaging process from inter-field signals before or after three adjacent fields. A second adder performs an inter-frame averaging process from inter-frame signals. One field difference and one frame difference are detected from the three adjacent inter-field signals thereby switching an output signal of the first adder and an output signal of the second adder in accordance with the magnitudes of the differences thus detected. In this way, aliasing interferences accompanied with bandwidth compression can be detected. By selecting an optimum eliminating filter, aliasing interference due to interfield sub-sampling and aliasing interference due to inter-frame sub-sampling can be eliminated.

Abstract: A digital image signal processing circuit for use in a VTR with camera has a signal input terminal to which an image pickup output signal or a video signal is supplied, an analog to digital converter for producing a digital image pickup output signal based on the image pickup output signal or a digital video signal based on the video signal, a digital signal processing portion including first, second and third digital signal processing circuit blocks, a system controller for conducting the change of operation, the change of circuit configuration or the change of circuit coefficient in each of the first, second and third digital signal processing circuit blocks, and signal output terminals from which recording luminance and carrier chrominance signals produced by the digital signal processing portion are derived.