Abstract: A chrominance transition corrector for restoring chrominance transitions after they have been degraded by a limited bandwidth channel converts input luminance and chrominance components, which represent a video image, from the time to the frequency domain. Correction coefficients are determined from a low frequency portion of the converted luminance component and the converted chrominance components. Corrected high frequency portions of the chrominance components are generated from the correction coefficients and a high frequency portion of the converted luminance component. The resulting converted and corrected high frequency portion of the chrominance components are then converted back to the time domain to produce chrominance output components, the chrominance transitions having been corrected.

Abstract: The invention pertains to a method and apparatus for performing dynamic purity correction to insure that color purity is maintained across the face of a color monitor. The monitor displays a plurality of pixels, each having a particular luminescence value. Each luminescence value has several color components (E.g. red (R), green (G) and blue (B)). A grid of luminance measurements is made across the face of the monitor for each color component. From these luminance value grids, smoothly varying correction values are computed for each color component of each pixel by the interpolation of cubic splines, such as a Catmull-Rom spline. Incoming digital video signals are multiplied by corresponding correction values to insure color accuracy of the monitor. In a preferred embodiment, the calculation of correction values is repeatedly performed in real time (at the display dot clock rate) in a single monolithic RAMDAC integrated circuit to increase speed, improve fidelity, and minimize use of memory space.

Abstract: Inserted in the transmission path (10) for transmitting a color signal of a color television signal is a signal switcher (12) with at least three switch positions (12a, 12b, 12c), the end positions of which are connected to the output (11.2) and input (11.1), respectively, of a delay line (11) contained in the transmission path. Connected to the transmission path (8) of the luminance signals is an edge detection arrangement (24) which, when a signal edge is detected in the luminance signal, generates a detection signal that oscillates about a zero line and has a zero crossing at the detection time, and controls the signal switcher in such a way that an associated color signal edge of the color signal, which has a steep slope and occurs at the point in time of the signal edge of the luminance signal, is transmitted. In the absence of detection of a signal edge, portions of both the undelayed and the delayed color signal are transmitted to the signal output (12.3) of the signal switcher.

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.