JPS61131993A - Chrominance signal adjuster - Google Patents

Abstract

PURPOSE:To reduce the size of a circuit scale and realize a full digital signal processing by realizing with a common circuit the functions to adjust hue and chromatic degree of saturation by multiplying the chrominance signal by a factor. CONSTITUTION:The chrominance signals that underwent a switching unit 3 and one that passed through a latch circuit 10 and a switching unit 5 are supplied respectively to multiplier 7 and 8 where they are multiplies by a multiplying factor. Respective products are subtracted 9, and are made chrominance signals. And when the signal S is '1' during the retrace line cycle, the switching unit 3-6 are made change to the input positions B, at the same time, the hue adjusting factor cos phi and the chromatic degree of saturation adjusting factor C are inputted to the multiplier 7. And to the multiplier 8, likewise, sinphi and the C are inputted. The respective product-outputs, C.cosphi and C.sinphi are held by latches 11, and 12 at the first transition of a signal SP. In cycles other than the retrace line cycle, the chrominance signals are respectively multiplied by the holding factors of the circuits 11 and 12 by multiplication 7 and 8, and the calculation is performed for adjusting hue and chromatic degree of saturation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a combination of color television signals,
, so-called color signal adjustment, such as hue and color saturation adjusters and automatic color saturation controllers in so-called digital television receivers, which perform signal processing up to the three primary colors of green 0 and blue 0 using digital circuits. It is related to vessels.

In a conventional color television receiver, a hue adjuster is used to display a received composite television signal on a receiving tube.
The hue of the reproduced color is changed according to the person's preference or the viewing conditions around the receiver. Similarly, a color saturation adjuster changes the color saturation of reproduced colors in accordance with a person's preference, viewing conditions around the receiver, and the like. Also,
Automatic color saturation controller (ACC) is a color saturation controller that changes the color saturation of reproduced colors when there is a frequency fluctuation in a color television signal due to the influence of the transmission path or the equipment on the sending and receiving sides. In order to prevent this, the input level fluctuation is detected from the amplitude fluctuation of the burst signal, which is unrelated to the image content, and the output level fluctuation is suppressed by the detected amount.

In conventional analog television receivers, the hue adjuster, color saturation adjuster, and ACC are configured as separate circuits, and even if the circuits are integrated into ICs, there are many external components and adjustment points, making it costly. , there were problems from a production standpoint. In order to solve this problem, in recent years, consideration has been given to completely digitalizing the signal processing up to the demodulation of color signals after the video stage.

Problems to be Solved by the Invention In a digital television receiver, in order to realize several functions for signal processing (the functions of the color signal adjuster mentioned above) using fewer parts and adjustment thresholds, it is necessary to One of the important issues was to standardize functional circuits.

Means for Solving the Problems The present invention solves the above drawbacks by realizing the functions of adjusting hue and color saturation using a common circuit.

All of the above-mentioned adjusters are configured with a circuit that basically multiplies a color signal by a coefficient. For this reason, the coefficients necessary for adjusting hue and color saturation are synthesized in advance during the vertical or horizontal retrace period (hereinafter referred to as retrace period), and the above-mentioned combined coefficients are used for normal screens. is multiplied by the color signal to make the desired adjustment.

Embodiment FIGS. 1 and 2 show an embodiment of the present invention, and first the outline of its configuration will be explained.

1 is a color signal input terminal, 2 is a clock signal input terminal, 3,
4, 5.6 are signal switchers, 7, 8 are first and second multipliers,
9 is a subtracter, 10, 11, 12, 19.20 are latch circuits, 13 is a chromaticity φ setter for hue change, 14 is a first coefficient generator that generates the coefficient of tuft φ, 15 is the coefficient of spider φ 16 is a coefficient setting/generator for setting color saturation coefficients, 18 is a retrace pulse signal input terminal, and 17 is a color signal output terminal. In addition, 21 and 22 are exclusive logic OR circuits (gx-OR circuits), 23 and 24
is a logical product circuit (AND circuit). Next, Figures 1 and 2
The operation of the circuit shown in the figure will be explained.

In FIG. 1, the color signal is input to the color signal input terminal 1 and passed through the signal switch 3, and the color signal passed through the launch circuit 10 and the signal switch 5 is sent to the first and second multipliers 7, respectively.
, 8. The chrominance signal is multiplied by a coefficient by the first and second multipliers, and the coefficient used to multiply the chrominance signal is a coefficient created in advance during the retrace period and held in the latch circuits 11 and 12.

The outputs of the first and second multipliers 7.8 are subtracted by a subtracter 9, and a color signal is outputted to a color signal output terminal 17.

Coefficients input to the first and second multipliers 7.8 for hue and color saturation adjustment are created according to the following principle.

Subcarrier frequency (fSC)
When sampling is performed at a frequency (4fsc) that is four times higher than
Y), -(RY), -(B-Y).

It has components of (R, -Y), . In order to change the hue, in an orthogonal plane composed of two axes (R-Y) and (B-Y), the amplitude of the color signal represented by a point on this orthogonal plane is changed from the origin with the origin as the center. It is sufficient to change the angle (phase) without changing the . Furthermore, in order to change the color saturation degree, it is sufficient to change the amplitude without changing the angle in the orthogonal plane. When the above angle is changed by φ and the amplitude is multiplied by C, the color signal (R,
-Y').

(B-Y) and a color signal (R
, -Y)' and (B-Y)' are expressed by the following equation.

...(2) ...(3) From this, to change the hue and color saturation, multiply the value at a certain sample point by C'cosφ, then multiply the value at the previous sample point by By multiplying C-8I11φ directly by 1 and subtracting it, a color signal with the hue changed by φ and the color saturation changed by 6 times can be obtained.

The coefficients of C''cosφ and C-5IrIφ are created during the winning period, and their operation will be described below.

When the retrace pulse signal is input to the retrace pulse signal input terminal 18, the signals shown in the timing chart of Fig. g3 are generated at S and SP in Fig. 2. s and sp in FIG. 2 are connected to S and SP in FIG. 1, and when the S signal is logic "1', the signal switchers 3, 4, 5.6 are switched to the input B side. First multiplication The coefficient section φ for hue adjustment and the coefficient C for color saturation adjustment are input to the multiplier 7, and C'casφ is output.Similarly, qinφ and C are input to the second multiplier 8, and C-8in
φ is output. C.φ and C-8ifIφ are respectively latched and held by latch circuits 11 and 12 at the rising edge of SP. Outside the retrace period, the coefficients held in the launch circuits 11 and 12 are input to the first and second multipliers 7 and 8, and are multiplied by the color signal to perform calculations for adjusting the hue and color saturation. Bamboo now.

4 and 5 show other embodiments of the present invention, the construction of which will be explained below, and for convenience, the same or equivalent parts as in FIGS. 1 and 2 are given the same reference numerals. 30 is a burst signal amplitude value detection circuit, 31 is an automatic color saturation control coefficient generator, 32.33 is a signal switch, 41 to 44 are latch circuits, 45 to 49 are exclusive OR circuits, and 50 to 54 are logic circuits. The product circuit 55 is an OR circuit. S in Figures 4 and 5
P, 81, 82. S3 is connected.

In this embodiment, the signal switchers 3, 4, 5, 6, 32.33 are connected to sl, s2. Logic “D” for s3
When the logic ``11'' is input, the input is switched to the input A side, and when the logic ``11'' is input, the input is switched to the input B side.

A timing chart of SP, SL, S2, and 83 in FIG. 5 is shown in FIG. 6. The basic operation of multiplying a color signal by a coefficient and calculating it for hue and color saturation adjustment is the same as that of the embodiment shown in FIG. The embodiment shown in FIG. 4 also includes an automatic color saturation control circuit (ACC).
An automatic color saturation control coefficient generator (ACC coefficient generator) 31 generates a coefficient that makes the amplitude of the burst signal detected by the burst signal amplitude value detection circuit 30 the same as the reference amplitude.

During the period of the clock signal □, the above-mentioned φ and C are input to the first multiplier 7, φ and C are input to the second multiplier 8, and one output of each multiplier □ is the clock signal. ■
At the rising edge of , the latch circuits 11 and 12 are launched. Next, during the period of the clock signal ■, the coefficients held in the latch circuits 11 and 12 at the rising edge of the clock signal ■ and the coefficient generated by the ACC coefficient generator 31 are multiplied by the first and second multiplication circuits 7 and 8, respectively. The output is latched into the latch circuits 11 and 12 at the rising edge of the clock signal (2). The coefficients and color signals created in this way are calculated by the first and second multipliers, and the subtracter 9
The hue and color saturation are adjusted by subtracting the two.

With the configuration that exceeds the effects of the invention, each function of the color signal adjuster can be operated by a common circuit, so the circuit scale is small, the number of parts is small, and the desired operation can be realized with an all-digital circuit.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a circuit diagram of the main part of FIG. 1, FIG. 3 is a timing chart of signals generated in FIG. 2, and FIG. 4 is a diagram of the present invention. A block diagram showing another embodiment, FIG. 5 is a circuit diagram of the part shown in FIG. 4,
Fig. 6 is a timing chart of the signals generated in Fig. 5, and Fig. 7 is a plane showing an example of changing the hue and color saturation in the (RY) and (B-Y) orthogonal planes. It is a coordinate diagram. 13...Angle setting device, 14.15...Coefficient device, 16
...Color saturation coefficient setter, 3, 4, 5, 6, 7, 8,
11.12...Means for multiplying and outputting. Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] In an orthogonal plane constituted by two axes of color difference signals (R-Y) and (B-Y), the amplitude of the color signal represented by a point on this orthogonal plane is changed around the origin. An angle setting device that sets the phase angle to an arbitrary angle φ in order to obtain an arbitrary hue by changing the phase without causing a coefficient unit that generates a coefficient, a color saturation coefficient setter that sets this coefficient in order to arbitrarily change the color saturation by changing the amplitude without changing the angle in the orthogonal plane; During the blanking period in one scanning period, the coefficient output from the coefficient unit is multiplied by the coefficient output from the color saturation coefficient setter, and this calculated value is held until the next scanning period, and A color signal adjuster comprising means for multiplying a color signal extracted from a composite television signal by the held calculation value during at least an effective scanning period in the one scanning period and outputting the result.