JP2000278706A - Cross color reduction processing circuit and television camera system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a false signal in a contour part in a vertical direction caused in the case of separating and eliminating a frequency component of a chromaticity signal from a luminance signal without degrading performance of a cross color reduction processing section. SOLUTION: A 1st arithmetic processing means 6 applies arithmetic processing to a 1st picture signal 1 and a 2nd picture signal S1 by one horizontal scanning line period before the 1st picture signal and provides an output. A 2nd arithmetic processing means 7 applies arithmetic processing to the 1st picture signal 1 and a 3rd picture signal S10 by one horizontal scanning line period after the 1st picture signal and provides an output. A 3rd arithmetic processing means 10 applies arithmetic processing to the 1st, 2nd and 3rd picture signals and provides an output. A 4th arithmetic processing means 5 applies arithmetic processing to the 1st picture signal and the arithmetic processing signal selected by a selection means 15 that selects any of the 1st, 2nd and 3rd arithmetic processing signals in response to a comparison result by a comparison means 14 that compares a 1st correlation between the 1st and 2nd picture signals with a 2nd correlation between the 1st and 3rd picture signals and provides an output of a video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cross-color obstruction in which, when a picked-up image is viewed on a television receiver or a television monitor, a color not originally present at a certain portion of the screen appears. And a television camera device using the same.

[0002]

2. Description of the Related Art As is well known, an image of a television being received and viewed by a television receiver in each home is an image signal captured by a television camera device. The television camera apparatus and the television receiver constitute one television system for transmitting a captured image signal. The television camera device constituting this television system generates and outputs an image signal in the following manner. 2. Description of the Related Art A television camera apparatus separates light from a subject incident through an imaging lens into three primary color lights of red (R), green (G), and blue (B) by a color separation prism, and performs color separation. R, G, and B primary light
Incident on the image pickup device for use (for example, a CCD of a solid-state image pickup device), the image pickup device for G, and the image pickup device for B. The R image sensor, the G image sensor, and the B image sensor photoelectrically convert incident primary color light into image signals, and output R image signals, G image signals, and B image signals. An R image signal, a G image signal, and a B image signal output from each image sensor are amplified by an amplifier circuit,
The signal processing circuit performs required amplification and signal processing, for example, detail correction, gamma correction, masking, and the like, to obtain predetermined R, G, and B image signals.

[0003] The predetermined R, G, and B image signals are further subjected to matrix processing in an encoder to obtain a luminance signal and a color signal I signal and a Q signal of a predetermined color system, for example, an NTSC color system. The I signal and the Q signal of the chrominance signal are respectively modulated into two color subcarriers having phases different from each other by 90 degrees to become a carrier chrominance signal, and multiplexed with a luminance signal to form a color image signal. Various color synchronizing signals are added to the color image signal generated in this manner, and the signal is transmitted as a decoded color image signal to a television receiver in each home via a television transmitter.

In such a television system, an image signal of a subject having a high spatial frequency in the horizontal direction, for example, clothing having fine vertical stripes is transmitted by a television camera device via a television transmitter.
When an image received by a television receiver is viewed, the originally striped portion of the clothes may appear to have a color that was originally absent. This is because when a television receiver separates a luminance signal and a chromaticity signal from an image signal, the high frequency component of the luminance signal, that is, the same frequency component as the chromaticity signal in the luminance signal is used as the chromaticity signal. This is because a part of the luminance signal is processed as a chromaticity signal, or the chromaticity signal may be mixed into the luminance signal. This is called color or cross color interference. In order to prevent the occurrence of the cross color, a cross color reduction processing means for removing in advance the frequency component of the chromaticity signal from the luminance signal is used in the television camera device.

FIG. 2 shows a specific example of a circuit configuration of a cross color reduction processing section of a television camera device according to the prior art. Each of the R, G, and B image signals is required. FIGS. 3 and 4 are diagrams illustrating each image signal delayed by each delay element of the cross-color reduction processing unit and the mutual relationship of each image signal on the screen. . In FIG. 2, predetermined R, G, and B image signals output from the signal processing circuit (not shown) of the television camera apparatus as described above (the digital processing television camera apparatus). Is input to the line delay element 22 and the subtraction circuit 26 via the input terminal 21. The line delay element 22 delays the image signal (see the waveform 301 in FIG. 3) input through the input terminal 21 by one line (one horizontal period) and delays it by one line (one line before). 3) The image signal (see the waveform 302 in FIG. 3) is output to the line delay element 23, the filter delay time compensation delay element 24, the subtraction circuit 26, and the subtraction circuit 27. The line delay element 23 further delays the image signal input from the line delay element 22 by one line, and further delays the image signal by two lines (two lines before) (FIG. 3). Is output to the subtraction circuit 27.

The subtraction circuit 26 inputs the image signal delayed by one line (one line before) (see S1 of the waveform 302 in FIG. 3) input from the line delay element 22 to the input terminal 21 one line later. The next image signal (see S2 of the waveform 301 in FIG. 3) is subtracted, and a difference signal S1-S2 (the upper and lower two lines forming the image, the difference between the lines S1 and S2 forming the screen 401 in FIG. 4, ie, The change is output to the shift operation circuit 28. The subtraction circuit 27 includes the line delay element 2
From the image signal delayed by one line (one line before) input from line 2 (refer to S1 of the waveform 302 in FIG. 3), the image signal is delayed by two lines input from the line delay element 23 (two lines before). ) Image signal (S0 of waveform 303 in FIG. 3)
), And subtracts the difference signal S1-S0 (screen 401 in FIG. 4).
, The difference between the lines S1 and S0, that is, the change) is output to the shift operation circuit 29.

[0007] The shift operation circuit 28 reduces the signal level of the difference signal input from the subtraction circuit 26 to １ ／, and outputs the difference signal having the 信号 signal level to the addition circuit 30.
The shift operation circuit 29 reduces the signal level of the difference signal input from the subtraction circuit 27 to １ ／, and outputs the difference signal having the 信号 signal level to the addition circuit 30. Adder circuit 30
Are the difference signal of the 信号 signal level input from the shift operation circuit 28 and the 1 /
The difference signal of the two signal levels is added, and the added signal is output to the shift operation circuit 31. The shift operation circuit 31 sets the signal level of the added difference signal input from the addition circuit 30 to 、, and outputs the added difference signal having the 信号 signal level to the bandpass filter (BPF) 32. .

The band-pass filter 32 passes only a signal in a predetermined frequency range centered on the color subcarrier frequency in the added difference signal input from the shift operation circuit 31 and outputs the signal to the subtraction circuit 25. The filter delay time compensating delay element 24 receives 1
An image signal delayed by a line and a bandpass filter 32
A delay element for matching the phase with a signal in a predetermined frequency range output from the
Comb filter operation is further performed on the image signal delayed by the line,
The image signal is delayed by a delay time (for example, a delay of several pixels) by a band-pass filter operation or the like, and an image signal input from the input terminal 21 and delayed by one pixel and a delay of several pixels by the comb filter operation is delayed. Subtraction circuit 25
Output to The subtraction circuit 25 converts the image signal delayed by one line and several pixels input from the filter delay time compensating delay element 24 into a predetermined frequency range centered on the color subcarrier frequency input from the bandpass filter 32. An image signal obtained by subtracting a signal and a signal in a predetermined frequency range, that is, a digital signal obtained by reducing a color subcarrier frequency component from each of the digitized R, G, and B image signals input to the input terminal 21. The output R, G, and B image signals are output from an output terminal 33 to another circuit, for example, an encoder.

As described above, the cross-color reduction processing section of the television camera device performs two line delay elements 22 and 23 and two subtraction on the R, G, and B image signals input from the input terminal 21. Circuits 26 and 27,
A comb filter (comb filter) that performs an operation of subtracting the image signals of the lines before and after the image signal of one line is configured. FIG. 6 shows frequency characteristics of the cross color reduction processing section shown in FIG. 2 as a comb filter.
The frequency characteristics of the comb filter are for each horizontal scanning frequency fh, that is, fh, 2fh, 3fh.
In each case, the amplitude rapidly attenuates.

On the other hand, as shown in FIG. 5, a television signal has a structure in which the energy spectra of a luminance signal and a chromaticity signal are alternately arranged for each horizontal scanning frequency. Are fh, 2fh, 3f
The energy of the peak decreases as the horizontal scanning frequency becomes higher and h..., and the chromaticity signal indicated by the dashed line has a higher peak around the chrominance subcarrier frequency fsc. It is known that the energy decreases as one shifts to lower-order chromaticity frequency components. Therefore, when a television signal having the characteristics shown in FIG. 5 is input to the comb filter having the characteristics shown in FIG. 6, only the chromaticity frequency components are passed and output. Also, as can be understood from FIG. 5, the energy spectrum of the chromaticity signal exists so as to be concentrated around the color subcarrier frequency fsc. By providing a frequency characteristic centered on the subcarrier frequency fsc, a horizontal chromaticity signal frequency component that allows only the frequency component of the chromaticity signal to pass therethrough is extracted. The chromaticity signal frequency component can be subtracted from the image signal.

[0011]

In a cross color reduction processing circuit and a television camera device using the same according to the prior art, in a cross color reduction processing section, a comb filter operation is performed on a portion where the vertical property of an image changes abruptly. Is performed, the comb filter operation is performed between lines having low correlation, and the output signal from the comb filter includes a large amount of the luminance signal component and is output. From this, only the frequency components of the chromaticity signal that should be removed are removed to the necessary frequency components as the luminance signal, which changes the luminance signal and outputs an image signal in which a false signal appears as shown in FIG. There is a problem.

The present invention solves the above-mentioned problems, and occurs when the frequency component of the chromaticity signal is separated and removed from the luminance signal without deteriorating the performance of the cross color reduction processing unit for reducing the cross color. An object of the present invention is to provide a cross-color reduction processing circuit which suppresses a false signal in a vertical contour portion, and a television camera device using the same.

[0013]

In order to achieve the above object, a cross color reduction processing circuit according to the present invention is a cross color reduction processing circuit for reducing cross color interference contained in an image signal. An image signal in a horizontal scanning line period (hereinafter, referred to as a horizontal image signal) and a second horizontal image signal one horizontal scanning line period before the first horizontal image signal are arithmetically processed. First arithmetic processing means for outputting the first arithmetic processing signal, the first horizontal image signal, and a third horizontal image after one horizontal scanning line period with respect to the first horizontal image signal. A second arithmetic processing means for arithmetically processing the signal and outputting a second arithmetically processed signal obtained by the arithmetic processing, the first horizontal image signal, the second horizontal image signal, and the third horizontal image signal. Arithmetic processing on the image signal and the arithmetic processing Third arithmetic processing means for outputting the obtained third arithmetic processing signal; a first correlation between the first horizontal image signal and the second horizontal image signal; Comparing means for comparing a second correlation with the third horizontal image signal, and the first arithmetic processing signal, the second arithmetic processing signal, and the second arithmetic processing signal according to a comparison result from the comparing means. Selecting means for selecting and outputting any one of the three processing signals; and performing a processing operation on the processing signal selectively output from the selecting means and the first horizontal image signal, and And a fourth arithmetic processing means for outputting the processed video signal.

More specifically, in the cross color reduction processing circuit according to the present invention, the comparing means may be arranged so that the comparing means has a first correlation higher than the second correlation and a difference between the first correlation and the second correlation. Is larger than a predetermined value, the selecting means selects and outputs a first operation processing signal, the second correlation is higher than the first correlation, and the first correlation and the second correlation are When the difference between the first correlation and the second correlation is larger than the predetermined value, the selection means selects and outputs the second arithmetic processing signal, and the difference between the first correlation and the second correlation is equal to the predetermined value. If it is smaller than the predetermined value, the selecting means selectively outputs the third arithmetic processing signal.

The television camera device of the present invention has a red
For each of the green and blue image signals, for each image signal in each horizontal period, a comb filter operation is performed on the image signal delayed by one line and the image signal in the horizontal period immediately before the image signal, and a first operation result is obtained. And a comb filter operation means for performing a comb filter operation on the image signal delayed by the one line and the image signal in a horizontal period immediately after the image signal, and outputting a second operation result And the first
Adding means for adding the result of the operation and the result of the second operation to output a result of the third operation; comparing the absolute values of the result of the first operation and the result of the second operation to obtain a correlation between image signal levels; Comparing means for judging the magnitude of the above, and outputting a control signal based on the judgment; selecting means for selecting the first, second, and third operation results based on the control signal and outputting one operation result; Band-pass means for passing and outputting a signal of a required frequency band in one calculation result to be output;
Filter delay time compensating means for outputting an image signal in which the phase of the image signal delayed by the line is matched with the phase of the signal in the required frequency band output from the band-pass means; and Subtracting means for removing a signal of a required frequency band and outputting an image signal from which the signal of the required frequency band has been removed, and reducing cross color without generating a false signal from each of the red, green and blue image signals It is intended to be.

In the television camera apparatus according to the present invention, for each of the red, green, and blue image signals, a plurality of line delays for performing a comb filter operation with the image signals of the preceding and following horizontal periods for each image signal of one horizontal period. A comb filter comprising an element and a plurality of subtraction circuits, a band-pass filter for passing a frequency band centered on the color subcarrier frequency, and a filter delay time compensating delay element for compensating a signal delay accompanying signal processing. In a television camera device having a cross color reduction processing unit provided to reduce the cross color, the cross color reduction processing unit includes:
A selector that selects an operation result from the comb filter; and a comparison circuit that compares the absolute value of the operation result from the comb filter to determine the magnitude of the correlation. The selector selects the selector based on the determination result of the comparison circuit. By selecting and removing a required operation result from the image signal, the cross color is reduced without generating a false signal.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing embodiments of the present invention,
An embodiment of the present invention will be described for a cross color reduction processing circuit according to the present invention and a cross color reduction processing section of a television camera device using the same. In order to prevent the comb filter operation from being performed in a portion where the vertical image quality of the image captured by the television camera device changes abruptly, that is, between lines having low vertical correlation,
A comb filter operation circuit for performing a comb filter operation on a line delayed by two lines above a line delayed by one line for reducing cross color, and a comb filter operation between a line without delay on the lower side thereof And two comb elements are used as comb filters. Then, the difference between the cross color reduction line and the line above it and the difference between the cross color reduction line and the line below it are compared one by one. It is determined that the correlation between the line for which the color is to be reduced and the line above or below the line is low, and the comb filter operation result of the line with a high correlation is used. If the magnitudes of the correlations are approximately the same, the result of the comb filter operation with the upper line and the result of the comb filter operation with the lower line are averaged, that is, the result of the comb filter operation using three lines. Use

The above comb filter operation is expressed by the following equation. Now, assume that an image signal of a line for which a certain cross color is to be reduced is S1, an image signal of an upper line (an immediately preceding image signal) is S0, and an image signal of a lower line (an immediately succeeding image). Signal) is S2,
The correlation between image signal levels in the vertical direction is divided into, for example, the following three patterns. | S1-S0 |-| S1-S2 |> TH ... | S1-S0 |-| S1-S2 | <TH ... || S1-S0 |-| S1-S2 || ≤ TH ... TH: In the case of a pattern of a threshold value (positive value) when comparing the magnitude of correlation, S is smaller than the difference amount of S1-S0.
Since the difference between 1-S2 is small, that is, the correlation between the line for reducing the cross color and the lower line is high, the comb filter operation with the lower line, that is,
(S1-S2) is used. Similarly, in the case of the pattern, the comb filter operation with the upper line, that is,
(S1-S0) is used. Also, as in the case of the above pattern, when the correlation between the line for reducing the cross color and the upper line is substantially the same as the correlation between the lower line, the The average value of the comb filter calculation result between the filter calculation result and the lower line, that is, S1− (S0 + S2) is used. As described above, in the television camera device of the present invention, the cross-color reduction processing unit performs the comb filter operation between lines having high correlation at the edge where the image quality in the vertical direction of the captured image changes rapidly. Since no calculation is performed between lines having low correlation, no false signal is generated. Also, in a so-called solid image in which the image quality in the vertical direction is uniform, or in a portion where the image quality of the image changes greatly for each line and the outline of the image cannot be recognized, a comb filter operation of the upper and lower sides and three lines is performed. , A high filter effect can be obtained.

An embodiment of a cross color reduction processing circuit according to the present invention and a television camera device using the same will be described below. FIG. 1 is a block diagram of a cross color reduction processing unit of a television camera device according to the present invention (a block diagram for one image signal, which is necessary for each of R, G, and B image signals, is shown). Will be described, and the embodiment will be described. In FIG. 1, 1 is
An input terminal 2 to which predetermined R, G, and B image signals digitized from a signal processing circuit (not shown) of the television camera device are input. A line delay element for delaying the time by one line (one horizontal period), 3 is a line delay element for further delaying the image signal delayed by one line by the line delay element 2 for one line, and 6 is a line delay element 2 The subtraction circuit 7 subtracts the undelayed image signal from the image signal delayed in step 1 and outputs a difference signal.
A subtraction circuit 8 for subtracting an image signal delayed by a line and outputting a difference signal; 8 a shift operation circuit (bit shifter) for reducing the level of the difference signal input from the subtraction circuit １ ／ to 9;
Reduces the level of the difference signal input from the subtraction circuit 7 by half.
Is an addition circuit for adding the 差 difference signals input from the two shift operation circuits 8 and 9, and 11 is the level of the added difference signal input from the addition circuit 10. The shift operation circuit for setting to 1/2, 14
The comparison circuit 15 compares the difference signals input from the shift operation circuit 8 and the shift operation circuit 9.
And a selector 12 for selecting one of the difference signals input from the shift operation circuit 9 and the shift operation circuit 11 by controlling the comparison output from the comparison circuit 14. A selector 12 selects a color in the difference signal selected by the selector 15. A band-pass filter for passing a signal in a frequency band centered on the subcarrier frequency,
Is a filter delay time compensating delay element for delaying an image signal input from the line delay element 2 by a signal delay by a comb filter or the like, and 5 is based on the image signal input from the filter delay time compensating delay element 4. A subtraction circuit for subtracting a signal in a frequency band centered on the color subcarrier frequency input from the bandpass filter 12; and an output 13 for outputting an image signal obtained by subtracting a signal in a frequency band centered on the color subcarrier frequency Indicates terminals.

Hereinafter, this operation will be described. A predetermined digitized R, G, B image signal output from a signal processing circuit (not shown) of the television camera device (an example of a digitally processed television camera device) is input to an input terminal 1. Is input to the line delay element 2 and the subtraction circuit 6 via The line delay element 2 has an input terminal 1
The image signal input through the line is time-delayed by one line, and the image signal delayed by one line (one line before) is delayed by the line delay element 3 and the filter delay time compensating delay element 4.
And to the subtraction circuit 6 and the subtraction circuit 7. The line delay element 3 further delays the image signal input by one line delayed from the line delay element 2 by one line, and further delays the image signal by one line.
The image signal delayed by two lines (two lines before) is output to the subtraction circuit 7.

The subtraction circuit 6 converts the image signal of the next one line input to the input terminal 1 one line later from the image signal delayed by one line (one line before) input from the line delay element 2. Subtract the difference signal (upper and lower 2
The difference between the image signals of the lines, that is, the change) is output to the shift operation circuit 8. The subtraction circuit 7 converts the image signal delayed by one line (one line before) input from the line delay element 2 to the image signal delayed by two lines (two lines before) input from the line delay element 3. , And outputs a difference signal (a difference between image signals of the upper and lower two lines constituting the image, that is, a change) to the shift operation circuit 9.

The shift operation circuit 8 sets the signal level of the difference signal input from the subtraction circuit 6 to 、, and outputs the difference signal having the 信号 signal level to the addition circuit 10, the comparison circuit 14 and the selector 15. Output to contact c. Shift operation circuit 9
Sets the signal level of the difference signal input from the subtraction circuit 7 to 1
/ 2, and the difference signal having the signal level of 1/2 is output to the adding circuit 10, the comparing circuit 14, and the contact point a of the selector 15. The adder circuit 10 adds the difference signal of the half signal level input from the shift operation circuit 8 and the difference signal of the half signal level input from the shift operation circuit 9, and shifts the added difference signal. Output to the arithmetic circuit 11. The shift operation circuit 11 sets the signal level of the added difference signal input from the addition circuit 10 to １ ／, and outputs the difference signal having the 信号 signal level to the contact b of the selector 15.

The comparison circuit 14 compares the absolute value of the difference signal of the half signal level input from the shift operation circuit 8 with the absolute value of the difference signal of the half signal level input from the shift operation circuit 9. The result of the comparison and the comparison of the magnitudes of the absolute values are output to the selector 15, and the selection of the contacts a, b, and c is controlled according to the comparison result. The selector 15 is controlled by the result of comparing the magnitudes of the absolute values input from the comparison circuit 14,
One of the contacts a, b, and c is selected, and the signal of the selected contact is output to the bandpass filter 12 via the contact d.
The bandpass filter 12 has a characteristic of passing a signal of a predetermined frequency band centered on the color subcarrier frequency, and only a signal of a predetermined frequency band centered on the color subcarrier frequency of the signal input from the selector 15 is provided. Through
Output to the subtraction circuit 5.

On the other hand, the filter delay time compensating delay element 4
Is a delay element for matching the phase of an image signal delayed by one line input from the line delay element 2 with a signal of a predetermined frequency band centered on the color subcarrier frequency output from the bandpass filter 12. Thus, the image signal delayed by one line input from the line delay element 2 is further delayed by several pixels delayed by a comb filter operation, a band pass operation, etc., and a delay time input from the input terminal 1 and caused by a comb filter operation, etc. An image signal delayed by about one line and several pixels is output to the subtraction circuit 5. The subtraction circuit 5 converts a signal of a predetermined frequency band centered on the color subcarrier inputted from the band-pass filter 12 from the image signal delayed by about two lines inputted from the filter delay time compensating delay element 4. Subtract. At this time, two signals that are input to the subtraction circuit 5 and subjected to the subtraction processing are:
The phases are the same. An image signal obtained by subtracting a signal of a predetermined frequency band centered on the color subcarrier frequency obtained by the subtraction process, that is, from each of the digitized R, G, and B image signals input to the input terminal 1 The digitized R, G, and B image signals with reduced color subcarrier frequency components are output from an output terminal 13 to another circuit, for example, an encoder (not shown).

To further explain the television camera apparatus of the present invention, it has a cross-color reduction processing section having the configuration shown in FIG. 1 which operates as described above, and receives an input from a signal processing circuit through an input terminal 1. Digital R,
For each of the G and B image signals, two line delay elements 2, 3
And two subtraction circuits 6 and 7 provided with a comb filter for performing a comb filter operation by subtracting the image signals of the lines before and after the image signal of one line. In the configuration shown in FIG. 1, an image signal for one line of an image signal input via an input terminal 1 is S2, and the image signal S2 is delayed by one line by a line delay element 2.
The image signal for one line is S1 and the image signal S1 delayed by one line is further delayed by one line by the line delay element 3, and the image signal for one line is S2 (see FIG. 3). When these three one-line image signals S0, S1, and S2 are viewed as, for example, three one-line image signals on the screen of the television receiver (see FIG. 4), the one-line image signal S1 is the center line and the image signal S for one line
0 is the upper line, and the image signal S2 for one line is displayed as the lower line.

Here, the image signal output from the subtraction circuit 6 is S1-S2, and the image signal output from the subtraction circuit 7 is S1-S0, and the comb operation circuit 8 and the shift operation circuit 9 perform the comb filter operation ( (S1-S2) / 2, (S1-
S0) / 2 is performed. Next, the absolute values | S1−S2 | and | S1−S0 |
In, it is determined whether the center line S1 has a high correlation with the upper line S0 or the lower line S2. When the correlation with the upper line S0 is high, that is, when the above expression holds, (S1-S0) / 2 is set to (selector 15).
(A), when the correlation with the lower line S2 is high, that is, when the above equation holds, (S1-S2) / 2
(The contact c of the selector 15), and when the difference between the correlation with the upper line S0 and the correlation with the lower line S2 is less than the threshold value, that is, when the above equation is satisfied, the addition circuit 1
0 and averaged by the shift operation circuit 11 [S1- (S0
+ S2) / 2] / 2 (contact b of the selector 15) and input to the next bandpass filter 12 by the selection of the selector 15. The bandpass filter 12 extracts a frequency component of the chromaticity signal from the signal selected and input by the selector 15 and outputs the same to the subtraction circuit 5. The subtraction circuit 5 subtracts the frequency component of the chromaticity signal input from the bandpass filter 12 from the image signal input from the filter delay compensation delay element 4. After performing the above-described cross color reduction processing on each of the digital R, G, and B image signals, a matrix circuit (not shown) uses, for example, a conversion equation Y = 0.299 × R + 0.587 × G + 0. 114
When the luminance signal Y is synthesized from the R, G, and B image signals by × B, a luminance signal from which the frequency component of the chromaticity signal has been removed can be obtained.

The threshold value used when the comparison circuit 14 determines the magnitude of the correlation is determined based on the required reduction amount of the false signal and the reduction amount of the cross color. As a criterion, a level at which a false signal is not noticeable when a standard test chart is imaged is set. In implementing the television camera device of the present invention, as an example, the threshold was set to 25% of the maximum value of the correlation difference amount, and an image was taken. However, a good image could be obtained. The threshold value to be set may be a fixed value. However, by setting the threshold value to a variable value according to the subject to be imaged, the threshold value is increased for a subject in which a cross color including a large amount of high-frequency components is likely to occur in the vertical direction. On the other hand, in the case of a subject having a small amount of high frequency components in the vertical direction and conspicuous outlines of the image, it is possible to use a method in which the threshold is lowered to increase the use ratio of the two-line comb. . As described above, the television camera device of the present invention has the cross-color reduction processing unit that does not degrade the performance of the comb filter used for reducing the cross-color, and provides a false image in the contour portion of the image in the vertical direction. Signal generation can be prevented.

[0028]

According to the present invention, without deteriorating the performance of the cross color reduction processing section for reducing the cross color, the vertical direction generated when the frequency component of the chromaticity signal is separated and removed from the luminance signal. It is possible to provide a cross-color reduction processing circuit that suppresses a false signal in a contour portion and a television camera device using the same.

[Brief description of the drawings]

FIG. 1 is a block diagram of a cross color reduction processing unit of a television camera device according to the present invention.

FIG. 2 is a block diagram of a cross color reduction processing unit of a television camera device according to the related art.

FIG. 3 is a diagram illustrating a delay of an image signal by a line delay element.

FIG. 4 is a diagram illustrating the position on the screen of an image signal delayed by a line delay element.

FIG. 5 is a schematic diagram of an energy spectrum of a television signal.

FIG. 6 is a diagram illustrating frequency characteristics of a comb filter.

FIG. 7 is a diagram illustrating frequency characteristics of a band-pass filter.

FIG. 8 is a diagram illustrating a normal image and an image in which a false signal has occurred.

[Explanation of symbols]

 1, 21 input terminal, 2, 3, 22, 23 line delay element, 4, 24 filter delay time compensation delay element, 5, 6, 7, 25, 26, 27 subtraction circuit, 8, 9, 11, 28, 29, 31 shift operation circuit, 10, 30 addition circuit, 12, 32 bandpass filter, 13, 33 output terminal, 14 comparison circuit, 15 selector.

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Claims (4)

[Claims] 1. A cross color reduction processing circuit for reducing cross color interference included in an image signal, comprising: an image signal (hereinafter, referred to as a horizontal image signal) for a first horizontal scanning line period; First arithmetic processing means for performing arithmetic processing on a signal and a second horizontal image signal one horizontal scanning line period before, and outputting a first arithmetic processing signal subjected to the arithmetic processing; A second image processing unit that performs an arithmetic operation on the horizontal image signal and a third horizontal image signal one horizontal scanning line period after the first horizontal image signal, and outputs a second arithmetic processing signal obtained by the arithmetic processing; 2 arithmetic processing means, arithmetically processes the first horizontal image signal, the second horizontal image signal, and the third horizontal image signal, and outputs the arithmetically processed third arithmetic processing signal Third arithmetic processing means, and the first horizontal image Comparing means for comparing a first correlation between the first horizontal image signal and the second horizontal image signal, and a second correlation between the first horizontal image signal and the third horizontal image signal; and Selecting means for selecting and outputting one of the first processing signal, the second processing signal, and the third processing signal in accordance with the comparison result of The arithmetic processing signal selectively output from the means and the first
And a fourth arithmetic processing means for arithmetically processing the horizontal image signal and outputting the arithmetically processed video signal. 2. The cross-color reduction processing circuit according to claim 1, wherein the comparing means has a first correlation higher than the second correlation and a difference between the first correlation and the second correlation. Is larger than a predetermined value, the selection means selects and outputs a first operation processing signal, the second correlation is higher than the first correlation, and the first correlation and the second correlation are If the difference between the first correlation and the second correlation is greater than the predetermined value, the selection means selects and outputs the second arithmetic processing signal. The difference between the first correlation and the second correlation is equal to or smaller than the predetermined value. A cross-color reduction processing circuit, wherein when the value is smaller than a predetermined value, the selection means selects and outputs a third operation processing signal. 3. For each of the red, green, and blue image signals, for each image signal in each horizontal period, a comb filter operation is performed on the image signal delayed by one line and the image signal in the horizontal period immediately before the image signal. And a comb filter operation means for outputting a first operation result, and performing a comb filter operation on the image signal delayed by one line and an image signal in a horizontal period immediately after the image signal, and a second operation result Comb filter operation means for outputting the first operation result and the second operation result; and addition means for adding the first operation result and the second operation result to output a third operation result. Comparing means for comparing the absolute values of the results to determine the magnitude of the correlation between the image signal levels and outputting a control signal based on the determination; selecting the first, second, and third calculation results based on the control signal and Selection means for outputting two operation results A band-pass unit that passes and outputs a signal of a required frequency band in the selected one calculation result; and a phase of the image signal delayed by one line is a required frequency band output from the band-pass unit. Filter delay time compensating means for outputting an image signal matched with the phase of the signal, removing the signal of the required frequency band from the image signal matched with the phase, and removing the signal of the required frequency band from the image signal. A television camera device, comprising: subtraction means for outputting; reducing cross color without generating a false signal from each of the red, green, and blue image signals. 4. Each of the red, green, and blue image signals includes, for each image signal in one horizontal period, a plurality of line delay elements for performing a comb filter operation with the image signals in the preceding and following horizontal periods, and a plurality of subtraction circuits. A cross-color reduction processing unit including a comb filter, a band-pass filter that passes a frequency band centered on the color subcarrier frequency, and a filter delay time compensation delay element that compensates for a signal delay caused by signal processing. In the television camera device configured to reduce the cross color, the cross color reduction processing unit compares an absolute value of a calculation result from the comb filter with a selector that selects a calculation result from the comb filter. A comparison circuit for judging the magnitude of the correlation, wherein the selector is selected based on the judgment result of the comparison circuit and a required operation result is displayed. By removing from the signal,
A television camera device wherein a cross color is reduced without generating a false signal.