JPH06245106A - Image pickup device - Google Patents

Abstract

PURPOSE:To prevent lines in pairs from being emphasized due to vertical aperture correction when a dynamic range is extended by extending an operating region of an image pickup device up to a nonlinear region. CONSTITUTION:From an output signal from an image pickup element 1 provided with plural kinds of color separation filters whose spectral characteristics differ, 1H delay circuits 3, 4 generate a 1H delay signal and a 2H delay signal, and an output signal from the image pickup element 1 and the 2H delay signal are summed by an adder 5. The signals are fed to a luminance signal generating section 7, from which a luminance signal is generated. Furthermore, an output signal from the adder 5 and the 1H delay signal are fed to limiter circuits 10a, 10b via LPFs 8a, 8b, by which the level of the signal of the image pickup element 1 is eliminated when the operating region of the element 1 enters even a nonlinear region requiring much light receiving quantity. Output signals from the limiter circuits 10a, 10b are fed to a BPF 11, in which a vertical aperture correction signal is generated and fed to an adder 13, which is used to correct vertical aperture of a luminance signal from the luminance signal generating section 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus having an image pickup element provided with a plurality of color separation filters having different color spectral characteristics for each line.

[0002]

2. Description of the Related Art A single-plate type solid-state image pickup device used in an image pickup device is provided with a color separation filter having different color spectral characteristics for each photoelectric conversion device arranged in a matrix in a photoelectric conversion portion of a light receiving surface. The photoelectric conversion element accumulates an amount of electric charge corresponding to the amount of color light separated by the corresponding color separation filter. The charges accumulated in these photoelectric conversion elements are read out in a predetermined order and output from the image pickup element as an electric signal. The output signal of this image pickup device is subjected to signal processing to generate a luminance signal and a color signal.

FIG. 2 shows an example of an array of color separation filters in such an image pickup device, where Cy is cyan and Ye.
Represents a color separation filter of yellow, G represents green, and Mg represents magenta. The horizontal direction is the horizontal scanning direction, and the vertical direction is the vertical scanning direction.

In the figure, the array of color separation filters is
With two horizontal arrangements and four vertical arrangements as one set, the arrangements of this set are sequentially repeated in the vertical and horizontal directions. Then, in each horizontal scan, one pixel is read out. That is, the first array Cy, Ye, ...
, And the second array G, Mg, ... Are read in the next horizontal scanning, the third array Ye, Cy ,. If reading is performed in a certain field in this way, in the next field, the second array G, Mg, ... And the third array Ye, Cy ,. Is read.

According to such readout, one pixel is the sum of charges from two photoelectric conversion elements arranged vertically and read out in the same manner. That is, in FIG. 2, the sum of the charges read from the photoelectric conversion elements of the color separation filters Cy and G is the charge of one pixel. In this way, the charges from the two photoelectric conversion elements arranged at different positions in the vertical direction are added to obtain the charge of one pixel.

The aperture correction circuit is for correcting the deterioration of the frequency characteristic due to the aperture of the image pickup device, and is disclosed in, for example, Japanese Patent Laid-Open No. 58-38074 and Japanese Patent Laid-Open No. 2-280.
As disclosed in Japanese Patent No. 496, the 1H delay signal and the 2H delay signal are obtained from the output signal of the image pickup device by using two 1H delay circuits (where 1H is one horizontal scanning period), and the output signal of the image pickup device is obtained. 1H delay signal is subtracted from the sum signal of the 2H delay signal and the 2H delay signal, and the vertical pre-shut and over-shu
The vertical aperture correction signal is generated, and the vertical aperture correction signal is added to the sum signal as the luminance signal or the sum of the sum signal and the 1H delay signal to emphasize the vertical contour portion.

[0007]

In the image pickup device as described above, the arrangement of the color separation filters read for each line (horizontal scanning line) is different, as described with reference to FIG. That is, in a certain line, (Cy +
G), (Ye + Mg), (Cy + G), (Ye + M)
g), ... Suppose that the pixel charges are read sequentially,
In the next line, (Ye + G), (Cy + Mg), (Y
e + G), (Cy + Mg), ... Sequential pixel charges are read out, and a combination of color separation filters forming pixels is different between the two lines.

An electric signal composed of such a column of pixel charges is
By passing through a low pass filter (LPF),
The luminance component is obtained by removing the sampling component of the pixel period, but as described above, between two lines,
When the combination of the color separation filters forming the pixels is different, the spectral sensitivity of each color separation filter is different, so that the level change of the luminance signal occurs between adjacent lines, and fine lines in the horizontal direction appear on the entire screen. This is called a line pair, but in the case of imaging in a normal region (linear region) where the amount of light received by the image sensor and the amount of charge are in a proportional relationship, this line pair is not particularly noticeable on the screen. However, when imaging is performed in a region (non-linear region) in which the received light amount is large and the received light amount and the charge amount are not in a proportional relationship, a line pair is generated even if uniform light is incident on the imaging surface. In particular, when the aperture correction is performed as described above, the line pair becomes noticeable. Therefore, conventionally, the image pickup range of the image pickup device has not been expanded to the non-linear region.

However, as another element that determines the image quality of the image pickup apparatus, the dynamic range of the image pickup element (hereinafter,
There is a D range) and its expansion is desired. As the method, conventionally, there are a method of increasing the gain of the signal processing circuit to lower the operating point of the image sensor, a method of increasing the coefficient of gamma correction, a method of performing the knee processing, etc. It is possible to shoot even a subject having a brightness enough to cause overexposure. However, on the other hand, noise is also increased and S / N is deteriorated, which is not a good idea.

Further, in order to expand the D range without causing S / N deterioration, it is conceivable to expand the image pickup area of the image pickup element to the non-linear area. However, as described above, this line pair appears remarkably. , The image quality is significantly degraded.

An object of the present invention is to solve such a problem and suppress the occurrence of line pairs even if an image pickup element having a different arrangement of color separation filters having different spectral sensitivities for each line images up to a non-linear region. An object of the present invention is to provide an imaging device that can be used.

[0012]

In order to achieve the above object, the present invention relates to a generation means for generating a vertical aperture correction signal from a luminance signal, and a correction for correcting the vertical aperture correction of the luminance signal by the vertical aperture correction signal. And means for suppressing the vertical aperture correction signal when the operating region of the image sensor enters the nonlinear region.

Further, according to the present invention, the luminance signal generating section generates a luminance signal from which a signal variation between adjacent lines is removed.

[0014]

When the amount of incident light is normal and the operating region of the image pickup device is within the linear region, vertical aperture correction similar to the conventional one is performed. When the amount of incident light increases and the operation region of the image sensor enters the nonlinear region, the vertical aperture correction signal is suppressed, and the aperture correction amount for the luminance signal at this time becomes small. Therefore, the line pair is not emphasized.

Further, by removing the level difference between the two lines of the luminance signal, it is possible to completely suppress the generation of the line pair even when the operation area of the image pickup device reaches the nonlinear area.

As described above, it becomes possible to image the image pickup device up to the non-linear region, and the D range can be expanded,
Moreover, generation of line pairs and S / N deterioration can be suppressed.

[0017]

1 is a block diagram showing an embodiment of an image pickup apparatus according to the present invention, in which 1 is an image pickup element, 2 is a preprocessing circuit, 3 and 4 are 1H delay circuits, 5 is an adder, and 6 is Luminance signal processing unit, 7 is a luminance signal generation unit, 8a and 8b are LPFs (low pass filters), 9 is a vertical aperture correction signal generation unit, 10a and 10b are limiters, 11 is a BPF (band pass filter), Reference numeral 12 is a horizontal aperture correction signal generator, 13 is an adder, and 14 is a gamma correction circuit.

In the figure, the image pickup device 1 is arranged with color separation filters as shown in FIG. 2, for example, and is capable of signal output operation even in a non-linear region where the amount of received light is very large. In the following, it is assumed that the image sensor 1 outputs a signal in such a non-linear region because the amount of received light becomes very large.
It is said that the operation area of the image sensor 1 has entered the non-linear area.

The output signal of the image pickup device 1 is first subjected to CDS processing for reducing noise and AGC processing for making the signal amount constant in the preprocessing circuit 2. The output signal of the preprocessing circuit 2 is delayed by the 1H delay circuit 3 to generate a 1H delay signal, and the 1H delay signal is delayed by the 1H delay circuit 4 to generate a 2H delay signal. The signal and this 2H delayed signal are added by the adder 4.
The output signal of the adder 5 and the 1H delay signal from the 1H delay circuit 3 are supplied to the luminance signal processing section 6.

Here, the output signal of the preprocessing circuit 2 and this 2
The H delay signal is added by the adder 5 so that the center of gravity of each line of the output signal of the adder 5 coincides with the line of the 1H delay signal at the same timing.

In the luminance signal processing unit 6, the output signal of the adder 5 and the 1H delay signal are supplied to the LPFs 8a and 8b to remove the sampling frequency component of the pixel, and the luminance signal is obtained from each of them. Here, the luminance signal output from the LPF 8b is particularly referred to as a 1H delayed luminance signal. The luminance signal and the 1H-delayed luminance signal obtained from each of the LPFs 8a and 8b are limited to the limiter circuits 10a and 1a.
It is supplied to the BPF 11 via 0b.

In these limiter circuits 10a and 10b, the limit levels are set which are substantially equal to the levels of the luminance signal and the 1H delayed luminance signal when the image pickup device 1 operates at the boundary between the linear region and the non-linear region. It has the input / output characteristics shown in the figure, and when the operating region of the image sensor 1 enters the non-linear region and the levels of the luminance signal and the 1H delayed luminance signal exceed the limit level, a signal component exceeding the limit level is output. remove. Further, the BPF 11 is, for example, the above-mentioned JP-A-58-38074 and JP-A-2-28049.
It consists of a subtracter such as the aperture correction circuit described in Japanese Patent Publication No. 6 and, by the luminance signal from the limiter circuits 10a and 10b and the 1H delayed luminance signal, represents a vertical pre-shoot or over-shoot. Form a vertical aperture correction signal. Due to the action of the limiter circuits 10a and 10b, when the operation region of the image pickup device 1 enters the non-linear region, the limiter circuits 10a and 10b output the signal of the above-mentioned limit level, so that the vertical aperture correction signal is suppressed. I can't get it. The vertical aperture correction signal thus obtained is output from the vertical aperture correction signal generator 9 and supplied to the adder 13.

The output signal of the adder 5 and the 1H delayed signal are
Further, the brightness signal is also supplied to the brightness signal generation unit 7, and the brightness signal is generated. This luminance signal is supplied to the adder 13 and the horizontal aperture correction signal generation unit 12 to generate a horizontal aperture correction signal.

In the adder 13, the vertical aperture correction signal from the vertical aperture correction signal generation unit 9 and the horizontal aperture correction signal from the horizontal aperture correction signal generation unit 12 are added to the luminance signal from the luminance signal generation unit 7. The vertical and horizontal aperture correction processing of the luminance signal is performed. The luminance signal output from the adder 13 is a gamma correction circuit 14
Is gamma-corrected.

As described above, in this embodiment, when the amount of incident light increases and the operating region of the image pickup device 1 reaches the non-linear region, the limiter circuits 10a and 10b of the vertical aperture correction signal generating unit 9 are set to the luminance. Since the image sensor 1 operates so as to limit the signal level and suppresses the vertical aperture correction signal, the image sensor 1 having a different color separation filter array configuration is used for each line, and the operating area of the image sensor 1 is extended to a non-linear area. Even if it is widened, the line pair is not emphasized. Therefore, the D range of the image pickup device 1 can be extended, and the high S
/ N is obtained, and the line pair is inconspicuous, so that an image of good quality can be reproduced.

FIG. 2 is a block diagram showing another embodiment of the image pickup apparatus according to the present invention. Reference numeral 15 is a multiplier, 16 is a gain control circuit, and 17 is an LPF. Are denoted by the same reference numerals and redundant description will be omitted.

In FIG. 2, the vertical aperture correction signal generator 9 includes a BPF 11, a multiplier 15 and a gain controller.
The circuit 16 and the LPF 17 are provided. The other parts are similar to those of the embodiment shown in FIG.

In the vertical aperture correction signal generator 9, the luminance signals 1 and 1 output from the LPFs 8a and 8b, respectively.
The H luminance signal is supplied, and the vertical aperture correction signal is generated by the BPF 5 and supplied to the multiplier 15. This vertical aperture correction signal can be obtained even when the operating area of the image sensor 1 enters the nonlinear area.

On the other hand, the luminance signal output from the luminance signal generation section 7 is supplied to the adder 13 and the horizontal aperture correction signal generation circuit 12 as in the embodiment shown in FIG. 1, and the vertical aperture correction signal generation is performed. It is also supplied to the circuit 9. In the vertical aperture correction signal generation circuit 9, this luminance signal is supplied to the LPF 17 to remove the component of the sampling frequency of the pixel, and the gain control circuit 16
Is supplied to. The gain control circuit 16 detects the level of the supplied luminance signal, and controls the gain of the multiplier 15 according to the detected level, as shown in FIG. That is, when the level of the luminance signal is the signal level when the operation region of the image sensor 1 is in the linear region, the gain of the multiplier 15 is kept constant and the image sensor 1
When the operating region of the signal is the signal level when it enters the nonlinear region, the gain of the multiplier 15 is gradually decreased as the level of the luminance signal is increased. As a result, the multiplier 15 obtains a vertical aperture correction signal in which the operating region of the image sensor 1 is in the non-linear region and the level is sequentially suppressed as the signal level increases.

The vertical aperture correction signal output from the multiplier 15 is the output signal of the vertical aperture correction signal generating section 10, and is supplied to the adder 13 and output from the brightness signal generating section 7. Vertical aperture correction processing is performed.

As described above, in this embodiment, when the incident light amount becomes large and the operation area of the image pickup device enters the non-linear area, the addition amount of the vertical aperture correction signal to the luminance signal is limited. Then, the same effect as the embodiment shown in FIG. 1 can be obtained.

FIG. 5 is a block diagram showing still another embodiment of the image pickup apparatus according to the present invention, in which 18 is a core circuit and 1 is a core circuit.
Reference numeral 9 is a core level control circuit, and parts corresponding to those in FIG.

In this embodiment, instead of the multiplier 15 and the gain control circuit 16 in the embodiment shown in FIG. 2, FIG.
As shown in FIG. 5, a core circuit 18 and a core level control circuit 19 are provided. The core circuit has a core region that cuts from 0 level to a predetermined level, and outputs a signal of a level higher than the predetermined level so that a signal component of a level lower than the predetermined level does not require noise or the like. It is to be removed as a signal. The core circuit 18 further makes the width of the core region variable.

The vertical aperture correction signal generated by the BPF 5 is supplied to the core circuit 18. The core circuit 18 is controlled by the core level control circuit 19 so that the LP
As shown in FIG. 7, the core level changes according to the level of the luminance signal from F17, and when the operating region of the image sensor 1 is in the linear region, the core width is constant, but When the operating region enters the non-linear region, the width of the core region of the core circuit 18 is widened, which causes the BPF 1
The vertical aperture correction signal supplied from No. 1 is sequentially suppressed as the level of the luminance signal increases.

As described above, in this embodiment, when the amount of incident light becomes large and the operation region of the image pickup device 1 enters the non-linear region, the coring process of the vertical aperture correction signal output from the BPF 11 is performed. As the core level increases, the vertical aperture correction signal is gradually suppressed, and the line pairs generated by the operation of the image sensor 1 in the non-linear region are removed, as in the embodiment shown in FIG.

FIG. 6 is a block diagram showing still another embodiment of the image pickup apparatus according to the present invention, in which 11a and 11b are B.
PFs, 18a and 18b are core circuits, and 20a and 20b are separation circuits. The parts corresponding to those in FIG.

In this embodiment, like the embodiment shown in FIG. 5, the line level is removed by controlling the core level of the core circuit. Especially, when the luminance signal is at a high level, The core level of the core circuit is controlled.

In FIG. 6, the luminance signals obtained from the LPFs 8a and 8b are separated into the low level component L and the high level component H by the separation circuits 20a and 20b, respectively. These separation circuits 20a and 20b have the separation characteristics shown in FIG. That is, these separation circuits 20a and 20b include
A separation level LV equal to the level of the luminance signal output from the LPFs 8a and 8b when the operating region of the image sensor 1 is at the boundary between the linear region and the non-linear region is set, and the operating region of the image sensor 1 is the linear region. When it is within the range, the low-level component L having a level corresponding to the level of the input luminance signal is output, but when the operating region of the image sensor 1 enters the non-linear region, the low-level component L having a level equal to the separation level LV. And a high-level component H having a level corresponding to a level equal to or higher than the separation level LV of the input luminance signal is output.

The low-level component L thus obtained from the separation circuits 20a and 20b is supplied to the BPF 11a, and the high-level component H is also supplied to the BPF 11b, so that a vertical aperture correction signal is generated by each. . Here, when the operation region of the image sensor 1 is in the linear region, the vertical aperture correction signal is obtained only from the BPF 11a. Further, when the operation utilization region of the image sensor 1 reaches the nonlinear region, the vertical aperture correction signal is obtained from the BPF 11b, but the separation circuits 20a, 20
The low-level component L obtained from b is the separation level LV.
Therefore, the vertical aperture correction signal is not output from the BPF 11a. That is, when the operating region of the image sensor 1 is in the linear region, B is entered when the operating region of the image sensor 1 enters the non-linear region from the BPF 11a.
A vertical aperture correction signal is obtained from each PF 11b.

The vertical aperture correction signal obtained from the BPF 11a is supplied to the adder 13 after the unnecessary component is removed by the core circuit 18a. Further, the vertical aperture correction signal obtained from the BPF 11b is supplied to the core circuit 18b. In the core circuit 18b, the core level control circuit 19 widens the width of the core region as the level of the luminance signal from the LPF 17 is higher, so that when the operating region of the image sensor 1 enters the nonlinear region,
As the amount of light received increases and the amount of output signal increases, B
The vertical aperture correction signal from the PF 11b will be suppressed. The vertical aperture correction signal from the core circuit 18b is supplied to the adder 13.

As described above, in this embodiment, the vertical aperture correction signal when the operation area of the image pickup device 1 is in the linear area and the vertical aperture correction signal when the operation area of the image pickup element 1 reaches the nonlinear area are separately generated. However, since the core circuit 18b suppresses only the aperture correction signal generated when the operation region of the image pickup device 1 reaches the nonlinear region, the core level of the core circuit 18b should be set to a large value. It is possible to suppress the occurrence of line pairs without impairing the sense of resolution.

FIG. 9 is a block diagram showing a specific example of the luminance signal generator 7 in each of the embodiments described above. 7a is a V.LPF (vertical LPF), and 7b is an H.LPF.
(LPF in the horizontal direction).

In the figure, the V · LPF 7a is composed of, for example, an adder, and the H · LPF 7b is an ordinary filter. Output signal of adder 4 (FIG. 1) and 1H delay circuit 3
The 1H delayed signal from is added by the V · LPF 7a to limit the vertical band. As a result, the change in the signal component for each line that causes the line pair is removed. V
The horizontal band of the output signal of the LPF 7a is limited by the H / LPF 7b, and the output signal of the LPF 7a becomes a luminance signal as an output signal of the luminance signal generation unit 7.

When the H · LPF 7b limits the band so as to remove the sampling frequency component of the pixel signal in the luminance signal, the LPF in FIGS. 2, 5 and 6 is used.
17 can be omitted.

As described above, according to this specific example, the luminance signal obtained from the luminance signal generation unit 7 has the signal component that changes for each line removed, and the component of the line pair included in the luminance signal is suppressed. Therefore, not only the enhancement of the line pair due to the vertical aperture correction can be prevented but also the line pair can be sufficiently suppressed.

The correction amount of the vertical aperture correction in the above-described embodiment may be controlled by the microcomputer.

Further, in each of the embodiments described above, it is not always necessary to use the specific example shown in FIG. 9 as the luminance signal generator 7, and the output signal of the adder 4 or the 1H delay signal from the 1H delay circuit 3 is used. May be passed through an LPF to obtain a luminance signal.

[0048]

As described above, according to the present invention,
Array configuration of multiple color separation filters with different spectral characteristics is 1
Even if the operating area of the image sensor different for each line is expanded to the non-linear area, the line pair can be suppressed, so that the dynamic range of the imaging device can be expanded and a high S / N video signal can be obtained. It is possible to reproduce various images.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image pickup apparatus according to the present invention.

FIG. 2 is a block diagram showing another embodiment of the image pickup apparatus according to the present invention.

FIG. 3 is a characteristic diagram showing input / output characteristics of the limiter circuit in FIG.

4 is a characteristic diagram showing input / output characteristics of the gain control circuit in FIG.

FIG. 5 is a block diagram showing still another embodiment of the image pickup apparatus according to the present invention.

FIG. 6 is a block diagram showing still another embodiment of the image pickup apparatus according to the present invention.

7 is a characteristic diagram showing input / output characteristics of the core level control circuit in FIG.

8 is a characteristic diagram showing input / output characteristics of the separation circuit in FIG.

9 is a block diagram showing a specific example of the luminance signal generation unit in FIGS. 1, 2, 5, and 6. FIG.

FIG. 10 is a diagram showing an example of an array configuration of color separation filters in a solid-state image sensor.

[Explanation of symbols]

 1 Image sensor 2 Pre-processing circuit 3,4 1H delay circuit 5 Adder 6 Luminance signal processing unit 7 Luminance signal generation unit 7a Vertical low-pass filter 7b Horizontal low-pass filter 8a, 8b Low-pass filter 9 Vertical aperture correction signal Generation unit 10a, 10b Limiter circuit 11 Bandpass filter 12 Horizontal aperture correction signal generation unit 13 Adder 14 Gamma correction circuit 15 Multiplier 16 Gain control circuit 17 Low-pass filter 18, 18a, 18b Core circuit 19 Core level control -Le circuit 20a, 20b separation circuit

Claims (6)

[Claims] 1. An image pickup device having a plurality of types of color separation filters having different spectral sensitivities different for each line and having an operation region expanded to a non-linear region, and an output signal of the image pickup device. Generating means for generating a vertical aperture correction signal from the brightness signal, correction means for correcting the vertical aperture of the brightness signal by the vertical aperture correction signal, and the vertical aperture when the operation area of the image sensor enters a nonlinear area. An image pickup apparatus comprising: a suppression unit that suppresses a correction signal. 2. An image pickup device having a plurality of types of color separation filters having different spectral sensitivities for each line and having an expanded operation region to a non-linear region, and an output signal of the image pickup device and two horizontal scans thereof. A signal generation means for generating a sum signal with a signal delayed for a period and a delay signal for delaying an output signal of the image sensor by one horizontal scanning period, and a luminance signal for generating a luminance signal from the sum signal and the delayed signal A generator, first and second limiter circuits for outputting a signal of the predetermined level when the sum signal and the delay signal are above a predetermined level set in advance, and the first and second limiter circuits And a bandpass filter for generating a vertical aperture correction signal from the output signal of (1), and the vertical aperture correction signal is added to the luminance signal output from the luminance signal generation unit to perform vertical aperture correction of the luminance signal. Addition Imaging apparatus characterized by comprising a vessel. 3. An image sensor having a plurality of types of color separation filters having different spectral sensitivities for each line and having an operation region expanded to a non-linear region, an output signal of the image sensor, and two horizontal scans of the output signal. A signal generation means for generating a sum signal with a signal delayed for a period and a delay signal for delaying an output signal of the image sensor by one horizontal scanning period, and a luminance signal for generating a luminance signal from the sum signal and the delayed signal A generation unit, a bandpass filter that generates a vertical aperture correction signal from the sum signal and the delay signal, an adder that adds the vertical aperture correction signal to the luminance signal from the luminance signal generation unit, and the luminance signal An image pickup apparatus comprising: a variable unit that changes an addition amount of the vertical aperture correction signal in the adder according to a level of a luminance signal from a generation unit. 4. The bandpass filter according to claim 3, wherein the bandpass filter includes a first vertical aperture correction signal based on the sum signal below a preset predetermined level and the delay signal, and the sum signal exceeding the predetermined level. A second vertical aperture correction signal is generated from the delay signal and the delay signal, and the variable means corrects the second vertical aperture correction signal in the adder according to the level of the luminance signal from the luminance signal generation unit. An image pickup apparatus characterized by changing an addition amount of signals. 5. The level according to claim 2, wherein the predetermined level is substantially equal to the levels of the sum signal and the delay signal when the operation region of the image sensor is at the boundary between the linear region and the nonlinear region. An imaging device characterized by. 6. The image pickup apparatus according to claim 2, 3, 4, or 5, wherein the luminance signal generation unit generates the luminance signal in which a signal of a frequency component that changes for each line is suppressed.