DE1537055A1 - Arrangement for handling the characteristic signals of a color television picture - Google Patents

Description

■ OSP GOMPAGITIE GENERaIE DE telegraphy SANS 47, rue Dumont d'ürville, Paris 16 ^e /]? Rance

Arrangement for handling the characteristic signals of a color television picture.

The invention relates to the channels for transmission and the treatment of the characteristic signals of a color television picture (for example the par value signals H, G, B or the chrominance signals) that enable the to eliminate distortions of the color image based on an asymmetry of these transmission channels. This will be done with compared to a saving in circuit complexity the conventional solution that does not have this advantage.

The larb information is in the known systems treated on separate channels. To maintain the essential properties of this information

is

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ORIGINAL INSPECTED

It is therefore necessary that the corrections or changes made to you intentionally or unintentionally are exactly the same for all information.

The aim of the invention is to let the color information traverse the same path, which is a simplification of the circuit arrangements and, on the other hand, the same properties in relation to the color information fe to each other, regardless of the state of the transmission channel.

In the following description, an image recording camera is mentioned as an application example, for example for the Gradation correction (gamma correction) of the three color value signals, the change in amplitude of these signals and the determination of the black level of these three signals, yes the invention is not limited to

"Bin further V _o Advantage of this system is making it possible to simultaneously perform an amplitude control of the three color information, because the method is characterized by a non-additive mixture of the color value signals.

Any area of an image is characterized by two sizes, namely by its color type, which only depends on the amplitude ratios of the different color value signals, and by its luminance,

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ORIGINAL INSPECTED

which only depends on the value of these amplitudes, and a by definition, the white area has a color type that is characterized by the following relationship: R = B = G.

If you consider the luminance of this white area ■

changes, resulting in a change in amplitudes of the signals R, B and G unta? Maintaining this When expressing a relationship, you get a value gradation that defines the areas between white and black is equivalent to. Such areas are referred to as "achromatic areas".

If a camera is scanning achromatic areas, it must be Equality of signals R, B and G are maintained regardless of the luminance of this area, even after correcting these signals in the three video channels, otherwise it can be determined during playback that the achromatic area tries to be colored in the color of the color value signal with the greatest amplitude. This lack { is especially in achromatic areas that are between white and lying black, disturbing and visible.

It is therefore necessary that the three video channels as possible are the same. However, it is difficult to achieve the same properties for the three video channels, and it is even more difficult to to maintain this equality over a longer period of time and during operation.

That

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The aim of the invention is to eliminate these drawbacks.

A system implemented according to the invention for the treatment and transmission of at least two characteristic signals a color television picture is characterized by an 'arrangement for multiplying these characteristic signals, that emits a resultant signal, a single channel for the treatment and transmission of that resultant Signals and a demultiplexing arrangement connected to the output of the channel to restore the treated characteristic signals.

The invention is described below by way of example with reference to the drawing. Show in it:

Pig. 1 an overview diagram of the arrangement according to the invention, in which time division multiplexing is applied, and

Pig. 2 and 3 diagrams to explain the mode of operation.

The invention is hereinafter described for the pail of its application in a color television camera having a tube with high resolution for the formation of a broadband Ieuohtdiohtesignals} but it is not on this limited·

Pig * 1 shows an arrangement 1 for the formation of Parb value signals, of any type known per se, at their outputs

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11, 12, 13 and 14 the uncorrected color value signals R, G, B or the luminance signal X of high resolution can deliver. Such an arrangement can contain, for example;

a) four tubes, which each have one of the signals R, Q-, B and Y deliver;

b) or three tubes, which supply the signals R, B and Y, respectively, while the third ear value signal Qt is restored with the aid of the three aforementioned signals.

The outputs 11, 12 and 13 are each connected to an electronic gate circuit 2, 3 or 4, which have a control input 20, 30 and 40, respectively.

The outputs of the gate circuit "2, 3 and 4 are together connected to the input of a correction and amplifier circuit, for example a circuit of known type, i which performs these functions. The output of this circuit is connected to the inputs of three electronic torso postures 2 ¹ , 3 ¹ and 4 ¹ , each of which has a control input 20 *, 30 * and 40 *. The outputs 8, 9 and 10 of the 'Uorcircuits 2', 3 ¹ and 4 ^1, together with the output 14, form the useful signal outputs of the camera.

A

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A pilot oscillator 6 is connected to a circuit 7 for forming sampling pulses which have outputs 72, 73 and 74. The output 72 is connected to the control inputs 20 and 20 ¹ , the output 73 to the control inputs 30 and 30 ^f and the output 74 to the control inputs 40 and 40 ¹ .

This arrangement works in the following way with reference to the Diagrams ™ of Pig «2:

The pilot oscillator 6 serves as a clock generator for the system. It delivers vibrations with a frequency that is sufficiently large in relation to the highest frequency of the signals R, G and B occupied frequency band. The oscillator under these conditions feeds the circuit 7 for the formation of strobe pulses which are at their outputs 72, 73 and 74 provides the pulses shown in Fig. 2a, 2b and 2c. These pulses can, depending on the circuit used, for example the frequency of the oscillator 6 or the have twice the frequency.

For a camera with four signals, the color channels of which are limited to 2MHz, a 4ae pilot frequency of 5 MHz can be used. The pulses delivered at output 73 are T ₁ - T / 3 compared to those delivered at output 72

Impulse.η

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Pulses delayed, where T is the pulse period. In a corresponding manner, the pulses delivered at output 74 are _{delayed by T 2} = 2T / 3 from the pulses delivered at output 72. The color value signals R, G and B are thus scanned by the gate circuits 2, 3 and 4, which are kept open for the duration of the pulses controlling them. The resulting signal, which is the sum of these three signals produced by the scanning, is fed to the input of a single circuit 5 which carries out the various necessary corrections.

Sampling with a signal in Consider the frequency of which is three times that of the previous case, eliminating the need there is no delay in the three groups of strobe signals.

^{The torso postures 2 1} , 3 ¹ and 4 *, which work synchronously with gate circuits 2, 5 and 4, make it possible to extract the corrected * rotation information, green information or blue information from the corrected signal. Thus, since the corrections for all three signals are made by a single circuit, it ensures that they are exactly the same and even if the characteristics of that circuit change over time or in operation, the relationship between the amplitudes will be the same of the corrected signals E, G and B are maintained so that the desired purpose is achieved

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From the way the camera works, it can easily be deduced that the! frequency of the oscillator 6 is sufficiently large compared to the highest frequency of the signals R, G and B occupied frequency band must be so that the Corrected signals taken from outputs 8, 9 or 10 with sufficient accuracy (except of course for the Corrections) the content of the uncorrected signals

* Play R, Gr and B.

Of course, the order of the color value signals in the resulting signal can be arbitrary.

The invention is wrden previously described for the case of a camera that includes a tube having a large A _u fiösung for the formation of the luminance signal.

However, it is obvious that they are in the same way

* suitable in the event that the luminance signal is synthetic by suitable linear combination of the color value signals supplied by the color image scanning device after the same Gamma correction is formed. In this case it is for Maintaining a sufficient resolution of the luminance signal beneficial to increase the number of exercises made on the signal that is related to its Participation in the formation of the synthetic light emitting diode most important, that is, in modern color television systems with the green color value signal G, that with 59 $

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Formation of the luminance signal J is involved. M _a n | can then, as in lig »? is shown, double the number of samples of the signal G with respect to the number of samples of the signals R and B. This can easily be achieved in that, for example, for the signals R and B, strobe pulses are used which have the same frequency as the signal emitted by the oscillator 6 and which are offset in time in a manner similar to that in the Pail of Pig.2, while sampling pulses Ta are used for the signal G, the frequency of which is twice as great as that of the signal from the oscillator 6.

In the examples described, time division multiplexing is used Applied «However, it is obvious that the invention is not limited to this multiplex system.

In particular, according to the invention, the three color value signals: for example frequency division multiplexing be subjected. This is done with every signal a suitably selected subcarrier is amplitude-modulated, ! These sub-beams must preferably be dimensioned in such a way that that the spectral components each modulated Insert U titei carrier in those frequency ranges the iron modulated the speciaile components of the others The carriers are not occupied, so the bandwidth of the entire spectrum and thus the one for the single channel erfördejEltche :. Saiiabteite rae & i be reduced. At the Outgoing As the only channel it is through 5 & ine demodulation

arrangement ^ * ίδ ORIGINAL INSPECTED

arrangement possible to separate the different 3 color value signals ⁱ from each other again.

One can of course also use the invention, for example apply phase multiplexing, in which one or several subcarriers with the signals to be processed phase modulated, or pulse multiplexing, which can be seen, for example, in the case of three color value signals can be imagined that the leading edge and the trailing edge of a pulse are caused by two of these Parbo value signals position-modulated, while the entire pulse is amplitude-modulated by the third signal.

Of course, the application of the discovery is not on Color television cameras are limited, but they can for example, also for mixing consoles for mixing applied to signals from multiple images

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Claims (1)

. JJ2H1 yeanocr: J. Claims 1 ·) Arrangement for processing and transmission τοη at least two characteristic signals efcies color television picture, characterized by an arrangement for multiplexing of these characteristic signals, which a resulting signal emits, a single channel for treatment and transmission of this resulting signal and an arrangement for de-multiplexing, which at the output asses single duct is connected and the treated restores characteristic signals. 2. A color television camera Sjit a Bildabtastrorriohtung that provides at least two color value signals, characterized by a Anordnunsjzur Zeltaultipifcxierung these color value signals, which outputs a resultant signal _t a single Kaui., Sur treatment and transmission of the resultant signal and an arrangement for Zeitdeaultiplexierung ₉ connected to the output of this single channel is connected and restores the treated color value signals. 3 · Color television camera according to claim 2, characterized in that that when using a scanning device which supplies at least three color value signals, the multiplexer arrangement has three Gate circuits contains, dl «each a control input exhibit. 909842/0718 'BAD original have, "and each transmit one of the color value signals, when a control signal is fed to the Steaerelngang, da ·· dl · outputs of the three gate circuit «η a with the input of the single channel are connected so that a defensive pulse generator has three outputs, each with one Control input of a dr three positions connected and deliver sampling pulses from an output sub next are laterally offset from one another, and that the demultiplexing arrangement has three more torso postures whose inputs are connected to the output of the single channel, and whose control inputs are connected to the Outputs of the sampling pulse generator are connected. 4. color television camera according to claim 3, characterized in that that when using a scanning device, the aueserdea delivers a broadband signal with high resolution, the pulse generator at its three outputs pulses the emits the same frequency, which is higher than the highest frequency of the frequency band of the color value signals 5. color television camera according to claim 3, characterized in that that when using a scanning device, the three color value signals assigned to the colors red, green and blue outputs, the pulse generator to the control inputs of the gate circuits, which are assigned to the color value signal corresponding to the green color, provides scanning input, whose frequency twice as large as the frequency of the sampling supplied to the control inputs of the other gate positions l.p-1 .. i.t. 9 0 9 8 4 2/0718