Abstract: A method and system for reducing the effects of false contouring and reducing color shading artifacts. An image signal 102 is dithered by the addition of a small noise signal from a noise generator 500. The added noise signal breaks up the edges of homogenous blocks of pixels, causing the created image to appear to have a smooth transition from one region to the next. The image dithering is especially useful in digital color image displays where processing performed on the chrominance portion of the image signal often causes quantization errors which lead to sharp transitions between similar shades when the input image included a smooth transition.

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

Abstract: A camera apparatus which can perform detail enhancement on a selected set of color signals. Fundamental color signals are respectively detected by a plurality of imaging devices and output in response to vertical transfer signals. For color signals on which detail enhancement is not to be performed, the vertical transfer pulse is sent to the corresponding imaging device at a reference timing. For the selected color signals on which detail enhancement is to be performed, the vertical transfer pulse is sent to the corresponding imaging device at a timing which is ahead of the reference timing. In one embodiment, vertical transfer pulses of the reference timing are generated, and additional pulses which are ahead of the reference timing are also generated. In another embodiment, vertical transfer pulses are continuously generated, but some pulses are selectively suppressed or subtracted to produce pulses of two different timings.

Abstract: A noise suppression apparatus suppresses noise of a luminance signal, for example, at a fringe of area of reception in a television receiver. The noise suppression apparatus includes a tuner circuit, an intermediate frequency amplification circuit, a video detection/amplification circuit, an AGC detection/amplification circuit, an RF AGC circuit, a sound/chrominance signal separation circuit, a luminance signal processing circuit and a luminance signal noise suppression circuit.

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: The present invention comprises an apparatus and method for automatically controlling the degree of temporal integration in a real time video image processor. The degree of integration may be determined by a combination of image brightness detected over a specific area of an image and motion detected within specific locations within the image. The apparatus comprises two main components, an integrating processor and integrating controller. The integrating processor receives an incoming analog video signal and converts it in an A/D converter into a series of digital pixel values. These digital pixel values may then be passed through an arithmetic processing unit where each pixel value may be fractionalized and summed with a fractionalized value of a geometrically corresponding pixel or pixels stored in a memory (i.e., temporal or recursive filtration). The sum of these fractionalized pixel values may then in turn be stored in memory as a new pixel values.

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 system for, and method of, enhancing a digitized image signal according to a helper signal architecture are described. The architecture includes an analysis filter, responsive to a digitized image signal, for filtering the digitized image signal, corresponding to a first frequency band, to produce a first frequency band signal. The first frequency band signal is then applied to a point operator, which modifies the first frequency band signal in accordance with a non-linear characteristic. The non-linear characteristic includes a first region having a negative slope for low amplitude input signals. The non-linearity further includes a second region having a positive slope for informational components of an input signal so that informational components of the first frequency band signal cause the point operator to produce a modified signal having components that relate to the input signal according to the positive slope.

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 processing video data for increased sharpness. The data undergoes a process by which it is filtered in two dimensions. Using separable, one-dimensional filters, the process cores the data to prevent noise enhancement and applies gain to the resulting data. Finally, both dimensional filtered components are then combined to form the final sharpened image. Because of the separable nature of the process and filters, either one of the dimensional filters could be eliminated, while retaining the robustness of the method.

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: Video signal processing apparatus and method which generates an aperture correction signal, or detail signal, which has a narrow width even for video signals that have low high frequency components. The processing apparatus generates a standard detail signal from the video signal, detects the maximum amplitude level of plural samples of the detail signal, and modifies the amplitude level of one of those samples as a function of the ratio of the sample's amplitude level to the detected maximum amplitude level. The apparatus further properly modifies the detail signal even when the positive and negative maximum amplitudes of the video signal are substantially different.

Abstract: In a noise reduction filter having a filter coupled to receive a plurality of input signal samples (.smallcircle.,.sym.) and furnishing noise-reduced signal samples, and a delay circuit coupled to the output of the filter and which furnishes a plurality of delayed noise reduced signal samples (X) to a further input of the filter, the samples (Pn.sub.1 . . . Pn.sub.n) applied to the filter are not directly neighboring samples.

Abstract: A method and circuit for reducing distortion of low level signals by efficiently separating noise and signal components using correlativity between respective red (R), green (G) and blue (B) channels and the amplitudes of the detail components. The detail enhancement method includes extracting detail components, determining signal/noise, cancelling noise or enhancing details and outputting a detail-enhanced image signal. Even if a high-pass frequency component of the input signal is smaller than a critical value, the input signal is accurately separated as a signal component or a noise component. The signal is cancelled only when the input signal is classified as a noise component.

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: A coring circuit for an input signal in the form of a differential input current having two components in phase opposition. A first pair of cascode transistors biased by a first reference voltage applies a first fraction of each of the components of the differential current to respectively first and second resistors. A second pair of cascode transistors biased by the first reference voltage provides a second fraction of each of the components of the differential current to a differential current output of the coring circuit and respectively to first and second branches of a differential stage that also receives voltages across the first and second resistors. Two coring current sources respectively connect first and second outputs of the differential stage to a supply voltage and are connected to each other through a third resistor.

Abstract: In a high definition flying spot telecine, noise from photomultiplier tubes and afterglow correctors reaches unacceptable levels at high frequencies. The circuit illustrated applied a conventional gamma correction to low frequency components (at 32) but applies a non-linear characteristic to the high frequency components (at 36). The characteristic is chosen to provide the optimum noise performance for positive or negative film. The two parts of the signal are then recombined by adders 40. High frequency processing is carried out on a multiplex of the R, G and B components to reduce complexity (at 16).

Abstract: A recording and reproducing apparatus which can prevent deterioration of the picture quality from being caused by an overshoot, a ringing or a noise component when, using a video tape recorder which can process two kinds of video signals having different aspect ratios, a video signal having a greater one of the aspect ratios is reflected on a television set. The recording and reproducing apparatus comprises a peaking circuit for adding an overshoot or a ringing to a video signal, a noise canceller circuit for cancelling noise from the video signal and a comb line filter for removing noise from the video signal. The peaking circuit, the noise canceller circuit and the comb line filter are capable of changing over the peaking frequency, the noise cancelling characteristic and the comb line filter characteristic thereof, respectively, in accordance with an aspect ratio of the 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 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: Direct current can be measured by passing a conductor carrying the current through the core of a toroidal transformer having a bias winding and a sensing winding. A pulse generator send pulses of magnetization current through the sensing winding so that the magnetization current produces a magnetic flux in the core which opposes a magnetic flux produced by the direct current carried by the conductor. A sensing circuit, connected to the sensing winding, detects the level of current through that winding to produce a measurement of the direct current carried by the conductor. A constant direct current is applied through the bias winding to increase the magnetic flux produced by the direct current carried by the conductor. Biasing the magnetic flux enables even small currents flowing through the conductor to be measured. Another version of the current sensor uses two transformers to measure direct current flowing in either direction in the conductor and provides an indication of that current's polarity.

Abstract: A circuit arrangement for improving the quality of video signals read out from a storage medium by isolating and processing a radio-frequency component which is added to a delayed video signal. An improvement can be achieved in particular in the signal details without any noise amplification effects and at the same time providing a natural picture. The circuit arrangement includes a synchronizing pulse separation stage for separating the radio-frequency component from the synchronizing pulses, a coring stage for suppressing signal components with signal values lying below a first threshold value and a controllable amplification stage, which influences the instantaneous signal value with a characteristic curve which is dependent on the signal value in a main signal branch and provides an increasing relative boosting of the radio-frequency component for greater signal values in the main signal branch.

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

Abstract: The present invention is a process for reducing the noise of a video signal (S1), in particular when reproducing a video signal stored on a video recorder, in which a window is defined around every signal value P (0,0,0) as an output signal value. A mean deviation (.sigma.) of the signal values in the window is established from the output signal values P (0,0,0), and an averaging of the output signal value is carried out with those neighboring signal values in the window which lie within limit values (So, Su) for the deviation from the output signal value P (0,0,0) dependent on the established mean deviation (.sigma.). The method is improved in its effectiveness by at least one threshold value (a1, a2) being fixed for the mean deviation (.sigma.=a/2), by the limit values (So, Su) for a mean deviation lying below the threshold value (a1, a2) being set with values (b) dependent on the established mean deviation (.sigma.) and by the limit values (So, Su) for a mean deviation (.sigma.

Abstract: In the digital processing of video signals, a vertical detail enhancement system is provided that has a transfer characteristic with a transitional region between a coring region and an active region split into three steps. The slopes of the first, second and third step regions are 25%, 50% and 75% of the enhancement gain, respectively. The levels of enhancement in the step regions are set at 25%, 50% and 75% of the level of enhancement in the active region. A vertical detail signal is compared with a coring level selected by a coring multiplexer among a plurality of hardcoded coring levels to set a coring point at the transfer characteristic. Then, the vertical detail signal is successively compared with the coring level incremented by the selected widths of the step regions to control a step choice unit defining a required attenuation of the vertical detail signal value. A paring level is selected by a paring multiplexer among a plurality of hardcoded paring levels.

Abstract: In a receiver for extended television signals in which a wide aspect ratio picture and at least one horizontal bar are jointly coded so as to form a standard aspect ratio picture, the at least one horizontal bar conveys vertical resolution enhancement information, and the extended television signal receiver includes an arrangement (107,111) for modifying the vertical resolution enhancement information to reduce an amount of distortions comprised therein, and an arrangement for combining the wide aspect ratio picture and the modified vertical resolution enhancement information to provide an enhanced wide aspect ratio picture.

Abstract: Television signal processing apparatus act on a received standard-bandwidth television signal to produce a high-definition-like video image relatively free of artifacts. A motion-adaptive line doubler operates in combination with a non-linear enhancer. In a practical implementation, the combination further includes a digital decoder. When the output of the decoder is applied to the line doubler, an interface provides a transition from the time base of the decoder to the time base of the line doubler. The non-linear enhancer includes bandwidth expanding enhancement for horizontal and/or vertical picture transitions.

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

Abstract: A waveform shaping apparatus in which no unrequired waveform shaping operation is performed even if its sensitivity is enhanced is provided. A signal (A) to be shaped in waveform is delayed by delay circuits (1 and 2) to produce signals (B and C). The signals (A, B and C) are applied to an original correction signal generating means (200a) and a control signal generating means (100a) to produce original correction signals (Ka and Kb), and control signals (Ha and Hb), respectively. A control circuit (13) selects the original correction signals (Ka and Kb), or a value "0" in accordance with the control signals (Ha and Hb) to generate a quasi-correction signal (L). The signal (L) is multiplied by a specified coefficient in a coefficient multiplier (14) to produce a correction signal (M), and the correction signal (M) is added to the signal (B) in an adder (5) to obtain an output signal (N) which has been shaped in waveform.

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 video image filtering system is described which utilises multi-tap filters (70). In order to reduce the effects of edge distortion due to the finite size of the input image, extension data is added both the beginning and end of each raster line of data fed to the multi-tap filter (70). The function of the extension data is to pre-load the multi-tap filter (70). With a system constrained to operate at a constant sample rate, there is insufficient inter-raster line separation to accommodate the extension data needed for a long multi-tap filter (70). The system transforms the input video signal format (24) to a reformatted video signal format (28, 30) in which either the horizontal blanking or vertical blanking period has been maximised at the expense of the corresponding other blanking period.

Abstract: An image signal processing device includes a logarithmic compression circuit, filtering circuit, filtering characteristic setting circuit and dynamic range/gain control circuit. The logarithmic compression circuit subjects an input image signal containing a color signal to the logarithmic compression. The filtering circuit serves to filter the input image signal. The filtering characteristic setting circuit adaptively sets the band pass characteristic of the filtering circuit according to the feature of the input image signal. The dynamic range/gain control circuit controls the dynamic range and gain of the filtered input image signal.

Abstract: A recording and reproducing apparatus which can prevent deterioration of the picture quality from being caused by an overshoot, a ringing or a noise component when, using a video tape recorder which can process two kinds of video signals having different aspect ratios, a video signal having a greater one of the aspect ratios is reflected on a television set. The recording and reproducing apparatus comprises a peaking circuit for adding an overshoot or a ringing to a video signal, a noise canceller circuit for cancelling noise from the video signal and a comb line filter for removing noise from the video signal. The peaking circuit, the noise canceller circuit and the comb line filter are capable of changing over the peaking frequency, the noise cancelling characteristic and the comb line filter characteristic thereof, respectively, in accordance with an aspect ratio of the video signal.

Abstract: A video white compression and peaking arrangement comprises a plurality of inverting amplifier transistors each tied to a common threshold level. RGB input video signals are applied to the inverting amplifier transistors which are ineffective for signals below the threshold level. The transistors are progressively turned on for input signals that exceed the threshold level resulting in non-linear negative feedback signals that compress the output signals by subtraction. A tuned circuit is coupled across the input of each inverting amplifier transistor for bypassing selected frequencies from the negative feedback effect and relatively peaking those frequencies in the output signal.