JPH0316076B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a method for obtaining
Hue in so-called digital color television receivers, in which signal processing for the three primary colors of red (R), green (G), and blue (B) is performed by digital circuits.
The present invention relates to so-called color signal regulators such as color saturation regulators and automatic color saturation controllers.

Prior Art In a color television receiver, a hue adjuster adjusts the hue of the reproduced color to suit the person's preference and the viewing conditions around the receiver when displaying the received composite television signal on the picture tube. It is something that can be changed. Similarly, a color saturation adjuster changes the color saturation of reproduced colors in accordance with a person's preference or viewing conditions around the receiver. In addition, the automatic color saturation controller (ACC) adjusts the color saturation of reproduced colors when there are frequency fluctuations in color television signals due to the influence of the transmission path or equipment on the transmitting and receiving sides. In order to prevent the intensity from changing, 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.

Such as hue adjuster, color saturation adjuster and
In conventional analog television receivers, ACC consists of a separate circuit, and even if the circuit was converted into an IC, there were many external parts and adjustments, which caused problems from a cost and manufacturing perspective. 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 points, each function is One of the important issues was to standardize the circuits that had the same characteristics.

Means for Solving the Problems The present invention solves the above drawbacks by implementing functions for 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 the hue and color saturation are created in advance by direct multiplication or by combining them during the horizontal retrace period (hereinafter referred to as the retrace period). The desired adjustment is performed by multiplying the color signal by a coefficient.

Embodiment FIG. 1 and FIG. 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, 1
2, 19, and 20 are latch circuits; 13 is a chromaticity φ setter for hue change; 14 is a first coefficient generator that generates a cosφ coefficient; and 15 is a second coefficient generator that generates a sinφ coefficient.
16 is a coefficient setting/generator for setting a color saturation coefficient; 18 is a retrace pulse signal input terminal; and 17 is a color signal output terminal. Also 2
1 and 22 are exclusive OR circuits (EX-OR circuits),
23 and 24 are logical product circuits (AND circuits).
Next, the operation of the circuits shown in FIGS. 1 and 2 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 latch circuit 10 and the signal switch 5 is input to the first and second multipliers, respectively. 7 and 8 are input. The color signal is multiplied by a coefficient by the first and second multipliers, and the coefficient used to multiply the color signal is a coefficient created in advance during the retrace period and held in latch circuits 11 and 12.

The outputs of the first and second multipliers 7 and 8 are subtracted by a subtracter 9, and a color signal is output to a color signal output terminal 17.

Coefficients input to the first and second multipliers 7 and 8 for hue and color saturation adjustment are created according to the following principle.

When a composite television signal is sampled at a frequency (4sc) that is four times the subcarrier frequency (sc), the color signal contained in it is (R-
Y), (B-Y), -(R-Y), -(B-Y), (R
−
Y), ... components. In order to change the hue, in an orthogonal plane composed of two axes (R-Y) and (B-Y), the color signal represented by a point on this orthogonal plane is moved from the origin with the origin as the center. It is sufficient to change the angle (phase) without changing the amplitude. Further, 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-mentioned angle is changed by φ and the amplitude is multiplied by C, the color signals obtained by sampling (R-Y), (B
-Y) and the color signals (R-Y)' and (B-Y)' whose hue and color saturation are changed is expressed by the following equation.

(B-Y)'(R-Y)'=Ccosφ-sinφ sinφ-cosφ (B-Y) (R-Y)...(1) Yotsute {(B-Y)'=C・cosφ・(B- Y) −C・sinφ・(RY)} …(2) {(RY)/=C・sinφ・(B−Y) +C・sinφ・(RY) …(3) From this, To change the hue and color saturation,
From the value at a certain sample point multiplied by C・cosφ,
By subtracting the value at the previous sampling point multiplied by C·sinφ, a color signal in which the hue is changed by φ and the color saturation is changed by a factor of C is obtained.

The coefficients of C·cosφ and C·sinφ are created during the retrace period, and their operation will be described below.

The retrace pulse signal is input to the retrace pulse signal input terminal 18.
, the signals shown in the timing chart in FIG. 3 are generated at S and SP in FIG. Second
S and SP in the figure are connected to S and SP in Figure 1, and when the S signal is logic "1", the signal switchers 3, 4, 5
6 is switched to the input B side. The first multiplier 7 has a hue adjustment coefficient cosφ and a color saturation adjustment coefficient C.
is input, and C·cosφ is output. Similarly, sinφ and C are input to the second multiplier 8, and C·sinφ is output. C·cosφ and C·sinφ are latched and held by latch circuits 11 and 12, respectively, at the rising edge of SP. The latch circuits 11 and 1 are
2 are stored in the first and second multipliers 7,
8 and is multiplied by the color signal to perform calculations for adjusting hue and color saturation.

4 and 5 show other embodiments of the present invention, and the configuration thereof will be explained below, but for convenience, the first embodiment is shown.
The same or equivalent parts as in FIG. 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, and 45 to 44 are latch circuits.
49 is an exclusive OR circuit, 50 to 54 are AND circuits, and 55 is an OR circuit. Figures 4 and 5
SP, S1, S2, and S3 are connected.

In this embodiment, signal switchers 3, 4, 5, 6, 3
2 and 33 operate so that when a logic "D" is input for the connected S1, S2, and S3, the input is switched to the input A side, and when a logic "1" is input, the input is switched to the input B side. .

A timing chart of SP, S1, S2, and S3 in FIG. 5 is shown in FIG. 6. The basic operation of multiplying a color signal by a coefficient and calculating it for hue/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), and the amplitude of the burst signal detected by the burst signal amplitude value detection circuit 30 is the same as the reference amplitude. An automatic color saturation control coefficient generator (ACC coefficient generator) 31 generates coefficients such that .

During the period of the clock signal, the first multiplier 7
The above-mentioned cosφ,C is input to the second multiplier 8.
sinφ, C is input to the , and the output of each multiplier is input to the latch circuits 11 and 11 at the rising edge of the clock signal.
It is latched at 12. Next, during the period of the clock signal, the latch circuit 11,
12 and the ACC coefficient generator 31
The coefficients generated are multiplied by the first and second multipliers 7 and 8, respectively, and their outputs are latched into latch circuits 11 and 12 at the rising edge of the clock signal. The coefficients and color signals thus created are operated on by the first and second multipliers, and the subtractor 9 subtracts them to perform hue/color saturation adjustment.

Effects of the Invention With the above configuration, each function of the color signal adjuster can be operated by a common circuit, so that 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 the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
2 is a circuit diagram of the main part of FIG. 1, FIG. 3 is a timing chart of signals generated in FIG. 2, FIG. 4 is a block diagram showing another embodiment of the present invention, and FIG. Figure 4 shows the main circuit diagram, Figure 6 shows the timing chart of the signals generated in Figure 5, and Figure 7 shows the timing chart of the signals generated in Figure 5.
The figure is a plane coordinate diagram showing an example of changing the hue and color saturation in the (RY) and (B-Y) orthogonal planes. 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.

Claims (1)

[Scope of Claims] 1. In a color signal adjuster for a color signal sampled and digitized using a clock signal having a frequency four times the subcarrier frequency, two of color difference signals (R-Y) and (B-Y) are provided. In the orthogonal plane formed by the axes, the phase angle is adjusted to obtain an arbitrary hue by changing the phase of the color signal represented by the points on the orthogonal plane, centering on the origin, without changing the amplitude. An angle adjuster that sets the angle φ to an arbitrary angle φ, and by being given the angle φ information,
a first coefficient unit that generates a coefficient of cosφ, a second coefficient unit that generates a coefficient of sinφ, and a color saturation level that can be arbitrarily changed by changing the amplitude without changing the angle in the orthogonal plane. a color saturation coefficient setter for setting a color saturation coefficient; a first latch circuit for delaying the color signal by one clock cycle of the clock signal; , a first multiplier that multiplies the coefficient of cosφ and the color saturation coefficient, a second latch circuit that holds the calculated value of the first multiplier until the next scanning period, and a coefficient of sinφ and a second multiplier that multiplies the color saturation coefficient; a third latch circuit that holds the calculated value of the second multiplier until the next scanning period; and during the effective video signal period of the next scanning period, The color signal and the calculated value held in the third latch circuit are delayed by one clock period from the value obtained by multiplying the color signal and the calculated value held in the second latch circuit by the first multiplier. a subtracter that subtracts and outputs a value obtained by multiplying by the second multiplier.