DE2228910C - System for recording a tri-line sequential color image signal - Google Patents

Description

What is distorted is that signal differences that occur in the case of information changes: to the direction of counting based on the W «k; Hngs, w, eise of the decoder (9) arise between the first and the identical second simultaneous signals are reduced.

2. System, jijach .. Claim 1, characterized in that the manipulated variable ( U _s ) is a correction signal (B _K , G _K ) , ¹ OaS your sequential signal ^ao , hmzajgef ügt WfCtJ .. ,, -? !,, ι , - < ,

3. System according to claim 1, characterized in that the sequential signal is one of the Decoder (9) is supplied to corresponding second decoder (12 to 14) during playback and the difference between the simultaneous signals produced at the output of the second decoder and the first simultaneous signals of the same type are used for predistortion (FIG. 2).

4. System according to claim 1, characterized in that the manipulated variable from the signal according to the predistortion is derived and acts in the negative feedback sense.

' ^L ' 5. System according to Claim 1, characterized in that the signal to be distorted is delayed by such a period of time (stage 5) until an evaluator (11) has generated the manipulated variable.

6. System according to claim 5, characterized in that the sequential signal is delayed by η lines (n = 1, 2 or 3) before the distortion.

■ 7 <SystemN ^ according to claim 1, characterized in that that the manipulated variable reduces the gain of the color channel of the display circuit.

8. System according to claim 7, characterized in that when the manipulated variable is a Exceeds the threshold value, the color channel is switched off during playback.

9. System according to claim 1, characterized in that the first simultaneous signals are fed to a computer (11) which contains the information about the mode of operation of the decoder (9) during playback and derives the manipulated variable that reduces the signal differences occurring therefrom. . ',''

H). System according to Claim 1, characterized in that the manipulated variable is derived from the signals (R, G, B) representing the primary colors.

11. System according to claim 1, characterized in that the manipulated variable is derived from the color difference signals (RY: BY) .

12. System according to claim 1, characterized in that the recording with an opposite a norm-SignaJ, reduced speed takes place.

13. System according to claim 1, characterized in that the manipulated variable phase and / or Am-

Color

Vrägers beeiafl ^^ ... _A ^ .

M.SysteiHrH ^ claim L characterized ^, that the manipulated variable only influences the lower frequency range of the signals to be recorded.

- ^ "ήη $ recording media with a low bandwidth of about 2 to 3 MHz, z. B. simple magnetic tape machines or an optical disc to record a color image signal, it is known (German Auslegeschrift 1 256 686) to record the three color signals R, G, B representing the primary colors line by line in a tri-sequence and for playback with a series connection of two delay lines to make them available again without gaps for one line duration each and with switches actuated at a line frequency. With this solution, the vertical solution is reduced. However, since the horizontal resolution is reduced by an even greater amount for color recording, this does not result in any disadvantage.

With such a system, errors occur during playback, especially when there are sharp transitions in vertical image direction, i.e. with horizontally running edges. This is due to the fact that during only the signal of a color separation is recorded on each line. A horizontal white line from the width of a line can e.g. B. cannot be reproduced correctly because all of them are required for white reproduction three color signals are necessary, but only one color signal is recorded during a line.

The invention is based on the problem of these occurring during playback with horizontal edges Reduce errors.

This object is achieved by the invention described in claim 1. Advantageous designs and further developments of the invention are given in the subclaims.

In the solution according to the invention, the signal to be recorded is examined based on the knowledge of the decoding process taking place during playback to determine which errors occur, ie which deviations of the recovered simultaneous signals from the original simultaneous signals occur. Depending on these deviations, the signal to be recorded is predicted in such a way that these deviations are reduced during playback. The manipulated variable can be obtained in an evaluator, for example a computer, which includes the parameters ^{1 of} the process and thus derives the manipulated variable from the original signals. Preferably, a decoder is provided during recording which corresponds to the decoder during playback and its output signals are compared with the original signals. The manipulated variable for the predistortion is then obtained from the deviation of these signals.

The invention is explained with reference to the drawing. Dario shows

1 shows the principle of operation of the invention,

Fig. 2 is a block diagram of an embodiment,

3 shows a diagram for explaining the mode of operation and

F i g. 4 shows a more detailed embodiment of part of the circuit according to FIG.

In FIG. 1, the color signals R, G, B at terminals 1, 2, 3 are converted into a sequential signal K, G, B with a switch 4 operated at a line frequency. This sequential signal arrives at the recording device 8 via a delay element 5, a distorter 6 and a coder 7. The decoder 9 includes, among other things, two line delay lines and three line-frequency switches in accordance with German Auslegeschrift 1256686.

The signals R, G, B are also fed to an evaluator 11, which contains the information about the mode of operation of the decoder. Because of ^ao this; The evaluator 11 acting as a computer can determine which errors occur when information changes perpendicular to the line direction due to the decoding process at the output of the decoder 9. The evaluator 11 generates a manipulated variable U _{s as} a function of these errors. This manipulated variable distorts the signal to be recorded in the distortion device 6 in such a way that the deviations occurring per se at the output of the decoder 9 are reduced. The delay element 5 has the effect that the manipulated variable U _s becomes effective at the correct point in time for distortion. There can be several delay elements 5 seen in front of the z. For example, delay 1, 2 or 3 lines. The manipulated variable t ' _s then acts in this delay chain at the point where the signal to be distorted is currently present.

In Fig. 2, the evaluator 11 contains a with the sequential signal R, (J, B fed decoder with two line delay lines 12, 13 and a line frequency operated switch 14. This decoder, which corresponds to the decoder 9 during playback, generates the simultaneous signals R ', G ' and B '. These are the signals that would arise during playback at the output of the decoder 9. In comparison stages 15, 16, 17 the signals R', G ', B' are compared with the original, correct signals R. , G, B. From the deviations between R ' and R, G' and G, B 'and B , manipulated variables U _{s are} obtained at the outputs of stages 15, 16, 17 In order that each manipulated variable can be added to the signal to which it belongs, the distorter 6 contains two line delay elements 5, 5 '.

This distortion can also take place in a kind of negative feedback by adding the already distorted signal is evaluated at the output of the equalizer 6. This is indicated by the dashed line connected evaluator 11 'shown.

3 shows the mode of action of the predistortion for an image which is red per se, in which line 7 is white

power becomes zero to 6.

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Signal K ₃ aurgeze: is recorded. the

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"',.». "Te 19 20 and two line- delay ™ −1 _& . _The manipulated variables from the outputs of the ^ ^td J ^ _{,; * steps 15>} f ₆ , 17 are assigned to the circuit, 6 ^ ^u _h , _{21 zugefu} hrt. the switch 21 bui _manipulated ^e _ize the Addierstue

l ™ n £ a "which is currently the sequential signal corrected by the slell available ^ 0 ^ ,. Output q ng de. Comparison stage ™ ^ - ·, iefer f and the signal B just at the l <; "5 ver / ögerungsgliedes 5 is present as J öBe ° u f connected the adder 19 8 η Γ transitions in the vertical direction h bi ß manipulated variable, it may. zweckmäßigsein? c J d £ \! i ederffibe 5 as a measure of the color reproduction to bc "of weo g, the color itude differenzsi-

^ ^Γ » ^η 8« η. ; ^ Jj _{e color rendering completely} changed

_{In the case of strong} color transitions, instead of a color error, there is a pure ^ «^ _{for a few} lines.

1 sheet of drawings

Claims (1)

Patent claims: 1. System for counting a first simultaneous Color image sjgnatern-derived tri-lines sequential color image signal which, when played back, is stored in a memory for line duration and line-frequency operated switches are converted back into second simultaneous signals is characterized by