JPH01248782A - Color signal aperture correction circuit - Google Patents

Abstract

PURPOSE:To prevent the deviation of hue at a change in a color by using information of a high frequency component or a low frequency component for each color signal of an electronic camera so as to obtain a gain control signal thereby controlling the gain. CONSTITUTION:Input signals 11, 12 pass through high pass filters 1, 2, high frequency component output signals 21, 22 are extracted and they are processed by absolute value processing circuits 24, 25 and an output signal is obtained. A comparator 26 compares outputs of the absolute value circuits 24, 25 and outputs logical '1' when the output of the absolute value circuit 24 is larger and a switch 27 passes an input signal 11 when the control signal is logical '1' and passes an input signal 12 when logical '0'. Then a data converter 28 uses multipliers 4, 5 to multiply the input signals 11, 12, the same value is given to the multipliers 4, 5 to obtain output signals 14, 15. Thus, only the amplitude is varied without varying the hue of the output signals 14, 15 when the input signal 14 is B-Y and the input signal 15 is R-Y, thereby applying aperture correction of the color signal without deviation of hue.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color signal aperture correction circuit for correcting resolution deterioration of color signals in signal processing of electronic cameras.

[Conventional technology]

In general, image signal resolution deterioration correction processing for electronic cameras is
In many cases, correction is applied only to the luminance signal, and even when correction for resolution deterioration is applied to the color signal, the correction is applied independently to each of the red, blue, and green primary color signals.

FIG. 6 is a block diagram of an example of a conventional color signal processing circuit. This conventional example includes input terminal groups 11, 12, 13, high-pass filters 31, 32, 33, adders 34, 35, 36
and output terminal groups 14°15.16, and each input terminal group 11°12.13 is connected to each high-pass filter 31.
．． 32゜33 and one input of each adder 34, 35, 36, high pass filter 31, 32゜33
Each output is connected to the other input of each adder 34, 35, 36, and the output of each adder 34, 35, 36 is connected to each output terminal group 14, 15, 16.

In the conventional circuit configured in this way, the input terminals 11, 12, and 13 receive red, blue, and green signals (hereinafter referred to as RGB) based on one image output from the process circuit of an electronic camera, for example. ) is input, high-frequency components of each color are extracted by high-pass filters 31 to 33, and by adding these signals to the original signal, deterioration in resolution is corrected independently for each color and high-frequency components are emphasized.

[Problem to be solved by the invention]

The conventional signal processing circuit shown in Fig. 6 processes each RGB color signal independently, so if a signal change occurs only in R of these RGB, only R has a large rise and fall. There is a drawback that signal changes occur and color shift occurs when RGB is superimposed.

An object of the present invention is to eliminate such drawbacks and to solve the difference (hereinafter referred to as R) between a color difference signal, that is, R and a luminance signal (hereinafter referred to as Y).
By amplifying the difference between B and Y (hereinafter referred to as B-Y) with the same gain, it is possible to correct deterioration in color signal resolution without causing hue shift. An object of the present invention is to provide a signal aperture correction circuit.

[Means to solve the problem]

The configuration of the color signal aperture correction circuit of the present invention is such that high-frequency components (
first and second high-pass (or low-pass) filters that pass the high-pass (or low-frequency components), a control circuit that inputs the outputs from these first and second filters and takes out a control output, and an output of this control circuit. and said first and second
The first output signal is obtained by multiplying the input signals of
and a second multiplier, and the control circuit includes first and second absolute value circuits that take the absolute values of the filter outputs from each of the filters and output them as first and second absolute outputs; a comparator that compares the outputs of the absolute value circuits and outputs "1" when the first (or second) absolute output is larger; and a comparator that outputs "1" when the first (or second) absolute output is larger; The present invention is characterized in that it includes a switch circuit that performs switching and outputs, and a data coefficient unit that converts the output of the switch circuit into a predetermined number corresponding to the positive/negative of the input and uses it as the control output.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. This embodiment includes an input terminal group 11.12, a high-pass filter 1.2, a control circuit 3, and multipliers 4 and 5. , and output terminals 14 and 15. Input terminal group 11,
'l 2 is high pass filter 1, 2 and multiplier 4.5
The outputs of high-pass filters 1 and 2 are connected to the inputs of control circuit 3, the outputs of control circuit 3 are connected to multipliers 4 and 5, and the output of multiplier 4.5 is connected to output terminal group 1.
4.15 is connected.

FIG. 2 is a block diagram showing an example of the control circuit 3 of FIG. 1. Input terminal group 21.22 and absolute value conversion circuit 24.2
5, a comparator 26, a switch group 27 that outputs the signals from the two signal input terminals 21 and 22 to the switching signal output terminal according to the control signal of the output of the comparator 26, and a ROM that converts the input signal. A data converter 28 is provided. The input terminal groups 21 and 22 are connected to the inputs of the absolute value circuits 24 and 25, and the input terminal group 21 is connected to the switch group 2.
7, the input terminal 22 is connected to the remaining input terminal 27b of the switching circuit, the output of the absolute value circuit 24 is connected to one input terminal 26a of the comparator 26, and the output of the insulation value circuit 25 is the remaining input terminal 26b of the comparator 26
The output of the comparator 26 is connected to the control signal input terminal of the switch group 27, the output of the switch group 27 is connected to a data converter 28, and the output of this data converter 28 is connected to the output terminal group 23. be done.

FIG. 3 is a waveform diagram illustrating the operation of this embodiment, and shows the magnitude of the digital signal as amplitude. In the figure, signals applied to input terminal groups 11.12, signals output from high-pass filters 21.22, output signals from absolute value circuits 24.25 (comparator input signals), and output from switch group 27. signal, the output of the coefficient unit 28, that is, the output signal from the control circuit 23, the output terminal group 14.15
It also shows the amplitude and hue of the color signal when the output signal from the terminal 14 is B-M and the output signal from the terminal 15 is R-Y.

In FIG. 1, input signals 11.12 pass through high-pass filters 1 and 2, and high-frequency component output signals 21.22 are extracted. In FIG. 2, each absolute value conversion circuit 24.
25 to obtain an output signal. The comparator 26 compares the outputs of the absolute value circuits 24 and 25, and outputs 1 if the value of the absolute value circuit 24 is larger than the value of the absolute value conversion circuit 25. When the control signal from the comparator 26 is "IJ", the switch 27 receives the input signal 11, and when the control signal is "0", the switch 27 receives the input signal 12.
It operates to pass through. Furthermore, the data converter 28 multiplies the input signals (11) and (12) by the multipliers 4 and 5, for example, a value of 0 to 1 if the input signal is a negative value, and a value of 1 to 2 if the input signal is a positive value. The same value is input to the multiplier 4.5 to obtain output signals (14) and (115). That is,
The gain of the input signal is controlled by the information in the higher frequency range of the input signal.

In this way, as shown in FIG.
The hue of the output signal 14.15 when 4 is B-Y and the input signal 15 is R-Y (J, = (Jb = 14 +
J15') f) Mira Possible'RI, it becomes possible to perform aperture correction of color signals without shifting the hue.

FIG. 4 is a block diagram of a second embodiment of the present invention. In contrast, this embodiment uses a low-pass filter.

This embodiment includes an input terminal group 11.12, a low-pass filter 6.7, a control circuit 8, multipliers 4, 5, an output terminal group 13.
14, the input terminal groups 11 and 12 are connected to the low-pass filter 6.7 and the multiplicand inputs of the multipliers 4 and 5, and the output of the low-pass filter 6.7 is connected to the input of the control circuit 8. The output is connected to the multiplier input of the multiplier 4.5, and the outputs of the multipliers 4, 5 are connected to the output terminal group 14.15.

FIG. 5 is a block diagram of an example of the control circuit 8 of FIG. 4. The input terminals 21 and 22 are connected to respective inputs of the absolute value conversion circuits 24 and 25 and the switch 27, and the absolute value conversion circuit 2
The output of 4.25 is connected to the input of a comparator 29 which is connected in opposite polarity to the first embodiment, and the output of the comparator 29 is connected to the switch 2 which outputs either of the two inputs according to the control signal.
7, and the output of the switch 27 is connected to the input of a coefficient multiplier 30 that converts the input signal.
The output of 0 is connected to the output terminal group 23 and configured.

In FIG. 4, input terminal group 11 has R-Y, terminal 12
B-Y is input to the low-pass filter 6.7, each low-frequency component is extracted, and the output is sent to the control circuit 8.
It is input to the input terminal group J11°12. In FIG. 5, the low frequency components of R-Y and B-Y are inputted to the input terminal group 21.22, processed by the absolute value converting circuit 24.25, and the comparator 29 switches the switch 27 to the R-Y, B-Y, Control is performed to pass the weaker low frequency component of B-Y. This control signal is input to the coefficient multiplier 30, and if the signal is input to the multipliers 4 and 5 in FIG.
If it is larger than a certain threshold value, a value between "0 and 1" is output. The value is outputted from the output terminal group 23, and by the control signal inputted to the multiplier 4.5 in FIG. It is possible to obtain an output signal with resolution deterioration corrected.

〔Effect of the invention〕

As explained above, the present invention provides color signals R-
A gain control signal is obtained using information on the high frequency component or low frequency component of each of Y and B-Y, and this signal is used to control R-Y and B-
By controlling the gain of Y in the same manner, there is an effect that the deterioration of the color signal resolution, that is, the color signal aperture correction can be corrected without causing a hue shift between colors.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a block diagram of one constituent unit of the control circuit 3 in FIG. 1, and FIG. 3 shows the operation of FIGS. 1 and 2. FIG. 4 is a block diagram showing the configuration of the second embodiment of the present invention, FIG. 5 is a block diagram showing an example of the configuration of the control circuit 8 in FIG. 4, and FIG. 6 is a timing chart showing the conventional color signal. FIG. 2 is a block diagram of an example of an aperture correction circuit. 1.2.31, 32.33... High pass filter, 3
．． 8... Control circuit, 4.5... Multiplier, 6.7...
・Low pass filter, 11-13, 21.22...Input terminal, 14-16.23...Output terminal, 24°25
...Absolute value circuit, 26.29...Comparator, 27.
...Switch, 28...Coefficient unit, 34...36...
・Adder. Agent Patent Attorney - Susumu Uchihara 1st part Z diagrammatic 4 叉g// almost f 6 diagrams

Claims (1)

[Claims] first and second high-pass (or low-pass) filters that pass high-frequency components (or low-pass components) of each color difference signal from the first and second input terminals; a control circuit that inputs the output of the control circuit and takes out a control output, and first and second multipliers that multiply the output of the control circuit and the first and second input signals to obtain each output signal, respectively. The control circuit includes first and second filters that take the absolute value of the filter output from each of the filters and output it as first and second absolute outputs.
The absolute value circuit and the output of these absolute value circuits are compared and the first
a comparator that outputs "1" when the absolute output of the filter (or the second) is large; a switch circuit that switches the output of the first and second filters to either one according to the output of the comparator; 1. A color signal aperture correction circuit comprising: a data coefficient unit that converts the output of the circuit into a predetermined number corresponding to the positive/negative of the input and uses the data as the control output.