JPH0797865B2 - High saturation image contour corrector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high-saturation image contour corrector for improving the quality of an image obtained by a television signal or the like.

2. Description of the Related Art As a conventional high-saturation image contour corrector, there is a method of adding color difference signals and adding the contour signal component to a luminance signal (for example, Haruo Sakata, "Resolution of Color Television High-Saturation Image", Television Academic journal VOL34, No.2, 1980).
Specifically, there is a configuration as shown in FIG. In Figure 3, 1,
2 and 3 are R (red), G (green), processed by the process circuit,
An input terminal to which a B (blue) signal is input, 4 is a correction signal matrix circuit that forms a correction signal, 5 is a correction contour signal forming circuit that forms a correction contour signal, and 6 is a gain control circuit that changes the gain of the correction contour signal , 7 is a noise slice circuit for removing minute noise, 8 is an adder for adding a luminance signal and a corrected contour signal, and 9 is an output terminal. The operation of the high-saturation image contour corrector configured as described above is shown in FIG.
This will be described with reference to FIG.

FIG. 4 is a diagram showing an example of the internal configuration of the correction signal matrix circuit 4 of FIG. 3, 11 is a matrix circuit for forming the luminance signal Y, 12, 13, 14 are subtractors, and 15, 16, 17 are A negative clip circuit for setting a negative signal to "0", and 18 is an adder. Therefore, <RY> + <GY> + <BY>("<>" is a symbol with negative "0") is output as a correction signal.

FIG. 5 is a diagram showing an example of the internal configuration of the corrected contour signal forming circuit 5 of FIG. 3, in which 21 is a Td time delay circuit, 22 is a coefficient unit for multiplying the value in the circle, and 23 is an adder. . When the correction signal shown in FIG. 6 (a) is input to the correction contour signal forming circuit 5, the correction contour signal shown in FIG. 6 (b) is obtained.
The frequency characteristics of the corrected contour signal forming circuit 5 are as shown in FIG.

However, in the high-saturation image contour corrector configured as described above, the contour is corrected when the luminance signal and the correction signal are in phase, but the contour is corrected when the luminance signal and the correction signal are in opposite phase. It blurs. This phenomenon will be described with reference to FIG. FIGS. 8A to 8E are waveform diagrams showing the signal waveforms of the respective portions in FIGS. 3A to 3E. Now, as shown in FIGS. 8A and 8B, the R signal and the luminance signal change, that is, the color is black to
When changing from R (red) to black to R (red) to white to R (red) (at this time, G (green) and B (blue) are set to "0".
(Correction signal = color difference signal R−Y), the correction signal changes as shown in FIG. 8 (c), and the corrected contour signal formed from this correction signal becomes as shown in FIG. 8 (d). The signal in which the corrected contour signal and the luminance signal are added, that is, the signal with the high saturation contour correction is as shown in FIG. 8 (e). As shown in FIG. 8E, when the brightness signal and the correction signal are in phase, for example, when the color changes from black to R (red) to black, the contour is corrected, but the brightness signal and the correction signal are corrected. When the signals are out of phase, for example, the color is R
When changing from (red) to white to R (red), the outline is blurred.

The above problems inevitably have drawbacks that cannot be avoided.

In view of the above point, the present invention has an object to provide a high-saturation contour corrector that does not blur the contour of a high-saturation image when the luminance signal is in reverse phase and corrects the contour of the high-saturation image when the luminance signal and the color difference signal are in phase. To do.

Means for Solving the Problems In order to solve the above problems, the present invention forms a luminance signal from R, G, and B input signals, and R,
A correction signal matrix circuit that forms a correction signal calculated by subtracting the luminance signal from the G and B input signals and adding only these positive components, and a correction contour signal forming circuit that forms a correction contour signal from the correction signal A luminance contour signal forming circuit that forms a luminance contour signal for polarity determination from the luminance signal; a polarity comparator that compares the polarities of the corrected contour signal and the luminance contour signal; and an output signal of the polarity comparator. Is provided with a control circuit that outputs the corrected contour signal when the polarities are the same, and an adder that adds the luminance signal and the output signal of the control circuit.

With the above-described configuration, the present invention compares the polarities of the corrected contour signal and the luminance contour signal with the polarity comparator and drives the control circuit with the output thereof. Thus, when the corrected contour signal and the luminance contour signal have opposite polarities, the corrected contour signal is not output, and the corrected contour signal can be output only when the corrected contour signal and the luminance contour signal have the same polarity. Therefore, when the corrected contour signal and the luminance contour signal have opposite polarities, the contour of the high-saturation image is not blurred, and when the corrected contour signal and the luminance contour signal have the same polarity, the contour of the high-saturation image can be corrected.

Practical Example FIG. 1 is a block diagram showing the configuration of a high saturation contour corrector according to an embodiment of the present invention. In FIG. 1, 1, 2 and 3 are input terminals for inputting respective R, G and B signals, 4 is a correction signal matrix circuit which forms a correction signal and a luminance signal, and 5 is a correction contour which forms a correction contour signal. A signal forming circuit, 6 is a gain control circuit that changes the gain of the corrected contour signal, 7 is a noise slice circuit that removes minute noise, 8 is an adder that adds the luminance signal and the corrected contour signal, 9 is an output terminal, and 10 is luminance. A luminance contour signal forming circuit that forms a luminance contour signal for polarity determination from a signal, 11 is a polarity comparator that compares the polarities of the corrected contour signal and the luminance contour signal, and 12 is an output signal of the polarity comparator 11. Is a control circuit for controlling the corrected contour signal by
1 to 9 are the same as the conventional example of FIG.

2 (a) to (g) are diagrams showing signal waveforms of respective portions of FIGS. 1 (a) to (g), and FIGS. 2 (a) to (d) are shown in FIGS. It is the same as d). FIG. 2 (e) is a luminance contour signal formed by the luminance contour signal forming circuit 10 from the luminance signal, and FIG. 2 (f) is an output signal of the polarity comparator 11 in which the corrected contour signal and the luminance contour signal are reversed. High level only when the polarity is set. The control circuit 12 does not output the corrected contour signal when the output of the polarity comparator 11 is at the high level. Therefore, the output signal subjected to the high-saturation contour correction by the high-saturation contour corrector of this embodiment is as shown in FIG. As can be seen from FIG. 2, when the corrected contour signal and the luminance contour signal have opposite polarities, that is, when the color changes from R (red) to white to R (red), the contour is not blurred and the corrected contour signal and the luminance are not blurred. The contour of the high saturation image is corrected only when the contour signals have the same polarity, that is, when the color changes from black to R (red) to black.

As described above, according to the present embodiment, the polarities of the corrected contour signal and the luminance contour signal are compared by the polarity comparator, and the control circuit is driven by the output, so that the corrected contour signal and the luminance contour signal have opposite polarities. In this case, the contour is not blurred, and the contour of the high saturation image can be corrected only when the corrected contour signal and the luminance contour signal have the same polarity.

EFFECTS OF THE INVENTION As described above, according to the present invention, when the correction signal and the luminance signal generated by the high-saturation image contour correction have opposite phases (such as when a part of the high-saturation image is shining), the contour The contour of a highly saturated image can be corrected by eliminating the phenomenon of blurring, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a high-saturation image contour corrector according to an embodiment of the present invention, and FIGS. 2 (a) to 2 (g) show the signal waveforms of the respective portions of FIGS. Waveform diagram, third
FIG. 4 is a block diagram showing a conventional high saturation contour corrector,
6 is a circuit diagram showing an example of the internal configuration of the correction signal matrix circuit 4 of FIG. 3, FIG. 5 is a circuit diagram showing an example of the internal configuration of the correction contour signal forming circuit of FIG. 3, and FIG. 6 (a). ，
7B is a waveform diagram for explaining the operation of the corrected contour signal forming circuit, FIG. 7 is a characteristic diagram showing frequency characteristics of the corrected contour signal forming circuit, and FIGS. 8A to 8E are FIG. a) to (e)
FIG. 3 is a waveform diagram showing signal waveforms of respective parts of FIG. 1,2,3 …… input terminals, 4 …… correction signal matrix circuit,
5 ... Corrected contour signal forming circuit, 6 ... Gain control circuit, 7 ... Noise slice circuit, 8 ... Adder, 9
...... Output terminal, 10 ...... Luminance contour signal forming circuit, 11 ...... Polarity comparator, 12 ...... Control circuit.

Claims (1)

[Claims] 1. A correction signal calculated by forming a luminance signal from R, G, B input signals and subtracting the luminance signal from the R, G, B input signals and adding only these positive components. A correction signal matrix circuit that forms a correction contour signal forming circuit that forms a correction contour signal from the correction signal; a brightness contour signal forming circuit that forms a brightness contour signal for polarity determination from the brightness signal; And a polarity comparator that compares the polarities of the luminance contour signal, a control circuit that outputs the corrected contour signal when the output signals of the polarity comparator indicate that the polarities are the same, the luminance signal and the A high-saturation image contour corrector, comprising: an adder that adds output signals of a control circuit.