摘要:
A method and an apparatus are set forth for encoding and decoding video to achieve bandwidth compression. In one form of the disclosure, two video signals (810, 850), representative of different images, can be transmitted using only the bandwidth (880) generally allocated to a single video signal, with little or no perceived degradation of image quality. In another form of the disclosure, motion indicative signals (970) are used in a technique that dynamically modifies the frequency band information to be stored and/or transmitted.
摘要:
A two stage interpolation system provides greater bandwidth for signals compressed and expanded by interpolation, such as video signals displayed in a zoom or enlarged mode. A finite impulse response filter (391) generates from a first signal of digital samples a second signal of digital samples representing signal points between the samples of the first signal. The first signal is delayed. The second signal and the delayed first signal are interleaved by a multiplexer (393) to produce a third signal of digital values having a sample density twice that of the first signal. A compensated variable interpolator (394) derives from the third signal a fourth signal of digital samples in which the frequency content of information represented by the first signal has been changed. In the case of enlarging the picture represented by a video signal, the video signal can be truncated in a FIFO line memory (395), prior to being delayed and processed by the finite impulse response filter (391). The compensated variable interpolator (394) can be controlled to provide selected ratios of compression or expansion.
摘要:
First and second field type detectors (702, 710) for first and second video signals have outputs indicating whether the video signals have first or second field types. The first video signal is synchronized with the second video signal for a combined display by a synchronous field memory (350) and an asynchronous multiple line memory (354). The field type of the second video signal is changed when necessary to match the field type of the first video signal to maintain interlace integrity in the combined display. A field type changing circuit (712, 714, 718) which controls the synchronizing, has a first mode of operation which delays writing a current field of the first field type by one horizontal line period, a second mode of operation which advances writing a current field of the second field type by one horizontal line period and a third mode of operation which maintains a current field type. A plurality of selectable interlace correction signals are generated, each being appropriate for one of the plurality of comparison outcomes.
摘要:
A circuit for compressing and expanding video data comprises a FIFO line memory (356) and an interpolator (337). A timing circuit (339) generates control signals for writing data into the line memory (356) and for reading data from the line memory (356) to compress and expand the data. The interpolator (337) smooths the data compressed or expanded in the FIFO line memory (356). A switching network (325, 327, 353) selectively establishes a first signal path in which the line memory (356) precedes the interpolator (337) for implementing the data expansion and a second signal path in which the interpolator (337) precedes the line memory (356) for implementing the data compression. The switching network (325, 327, 333) is controlled according to selected display formats requiring compression or expansion, for example by a microprocessor.
摘要:
A field synchronization system for asynchronous video signals, comprises a video display synchronized with a first video signal having a first line rate component and a first field rate component. A second video signal having a second line rate component is first stored in a field memory, having synchronous write and read ports. The second video signal is thereafter speeded up in a multiple line memory (354) having asynchronous write and read ports and independently resettable write and read pointers. The second video signal may be subsampled, written and read into and out of the field memory respectively and written into the multiple line memory, all synchronously with the second line rate component. The second video signal is read out of the multiple line memory (354) synchronously with the first line rate component. The write pointer is reset by a circuit (320) which samples the first field rate component with the second line rate component. The read pointer is reset by a circuit which samples the first field rate component with the first line rate component.
摘要:
Die Erfindung bezieht sich auf ein Farbfernsehsystem zur Aufnahme, Übertragung und Wiedergabe von Farbfernsehbildern. Das System ist besonders geeignet zur Aufnahme von Farbbilder im Weltraum und Wiedergabe auf Erden. Das System arbeitet ohne Farbhilfsträger und ist der Lage die Farben ohne Beeinträchtigung der Qualität auf dem Übertragungsweg und störende Nachzieheffekte bei der Wiedergabe zu erzeugen.
摘要:
Le système se compose d'un transmetteur et d'un récepteur. Le transmetteur comprend, un dispositif de matriçage (1), deux convertisseurs analogique-numérique (2), des moyens de mémorisation constitués par une mémoire de luminance (3) et une mémoire de chrominance (4), une logique de mise au format (5), des moyens de conversion numérique-analogique constitués d'un synthétiseur programmable (6) et d'un convertisseur fréquence-tension (7). Il comprend également un compteur d'adressage rapide (8), un compteur d'adressage lent (9), un maitre oscillateur (10), un dispositif de synchronisation des signaux de chrominance et de luminance (11) et un dispositif de filtrage (12). Des suites de signaux de luminance séparées de suites de signaux de chrominance par des signaux de repérage sont engendrées par le transmetteur pour permettre au récepteur de retrouver sans ambiguité les signaux de luminance et de chrominance en s'affranchissant des variations de la position de l'angle de phase de la sous-porteuse couleur. Application : transmission de signaux vidéo sur canaux à bande étroite et enregistrement et lecture sur bande magnétique de ces signaux.
摘要:
A television receiver comprises a sawtooth .generator (11) for generating sawtooth waves in dependence on a synchronizing'signal in an incoming positively or negatively modulated (such as SECAM or PAL respectively) composite video signal, a voltage detector (12) capable of generating an output waveform in response to the peak voltage of the sawtooth wave, during the field response period, the output waveform having a relatively high level or a relatively low level depending on the modulation polarity of the incoming video signal composite video signal, a smoothing circuit (13) for generating an output in response to the output waveform over the field period of the incoming video signal, and a switch driver (14) for effecting a control, such as video modulation polarity switching, in dependence on the output of the smoothing circuit (C13).