JP2000350231A - Video signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video signal processor which can make color correction according to the difference in the color temperature of illumination light without altering the constitution of a light source unit. SOLUTION: The video signal obtained by picking up an image of an object lit with the illumination light by an image pickup device 16 is corrected by a white balance correcting circuit 35, etc., and projected on a monitor device 35. At this time, a color correcting circuit 37 detects the difference in hue due to the difference in the color temperature of the illumination light on the basis of the correction quantity obtained by the white balance correcting circuit 35 and makes color corrections according to the difference in the hue. Consequently, the color corrections corresponding to the difference in the color temperature of the illumination light can be made without altering the constitution of the light source device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus for performing video signal processing on an image signal obtained by an imaging apparatus provided in an endoscope, and particularly to a means for improving color reproducibility. The present invention relates to a video signal processing device.

[0002]

2. Description of the Related Art In recent years, an elongated insertion portion has been inserted into a body cavity to observe a gastrointestinal tract such as an esophagus, a stomach, a small intestine, or a large intestine, or a trachea such as a lung, and inserted into a treatment instrument channel as necessary. 2. Description of the Related Art Medical endoscopes capable of performing various treatments using a treatment tool are widely used. Also, in the industrial field, industrial endoscopes capable of observing and inspecting internal scratches and corrosion of boilers, turbines, engines, chemical plants, and the like are widely used. In general, an endoscope is provided with an illumination device that irradiates illumination light supplied from a light source device to a subject, and is built in the distal end of an insertion portion or attached to an eyepiece to capture an image of the subject, that is, perform photoelectric conversion to obtain an imaging signal An imaging device is provided. In an endoscope provided with such an imaging device, a subject image can be handled as an electric signal, so that correction processing is performed on an observed image to improve image quality,
There is an advantage that the observation image can be electronically recorded and edited.

A light source device emits white light, and R (red), G (green), and B light sources correspond to the difference in the configuration of the imaging device.
There are those which sequentially emit the three primary colors (blue) in a time-division manner. Further, even in a light source device that emits white light, the color temperature of the illumination light differs depending on the light source used in the light source device.
For example, of a xenon lamp and a halogen lamp generally mounted on a light source device of an endoscope apparatus, the xenon lamp has a higher color temperature than the halogen lamp. As described above, the color temperature of the illuminating light emitted from the light source device differs depending on the type. In the sequential light source device, a color filter that separates the illumination light from the light source lamp into three primary colors in a time-division manner is provided, and the difference in the color filters causes a difference in spectral characteristics.

[0004] The image pickup device is provided with, for example, a CCD (Charge Coupled Device). An image pickup apparatus is a so-called simultaneous type in which each color component of a subject image obtained by irradiating a subject with white light is spatially divided and simultaneously imaged, and a subject is sequentially irradiated with, for example, three primary colors of RGB in a time-division manner. Of the subject image to be imaged in a time-division manner. In addition, a simultaneous imaging apparatus is called a single-panel type in which each color component is imaged by one CCD,
Each component is classified into, for example, a so-called three-plate type in which images are captured by a plurality of, for example, three CCDs. In a simultaneous imaging device,
A color separation optical system for optically spatially dividing each color component of the subject image is provided on the optical path of the subject image, and the sequential type imaging apparatus does not have this color separation optical system. There is a difference. In the case of a single plate type, this color separation optical system is provided, for example, on the front surface of the light receiving surface of a CCD.
Each pixel of D is constituted by a color chip filter that transmits a different color component to each pixel. In the case of a three-plate type, for example, it is constituted by an optical member that separates each color component in the direction of each CCD. A color chip filter used in the single-chip simultaneous imaging apparatus includes a primary color filter that spatially divides a subject image for each of the three primary color components, a complementary color such as Mg (magenta),
There is a complementary color filter that spatially divides a subject image for each color component of Cy (cyan), Ye (yellow), and G (green).

[0005] An image pickup signal obtained by picking up a subject image by the image pickup device is converted into a video signal that can be displayed on a monitor by a video signal processing device, and this video signal is displayed on the monitor device.

However, the color balance of a video signal obtained from an image pickup signal obtained by an image pickup apparatus depends on a difference in color temperature and spectral characteristics of illumination light by a light source device used, a color chip filter provided in the image pickup apparatus, and the like. Large variations occurred due to differences in spectral characteristics of the color separation optical system. For example, in an imaging signal obtained by a plurality of endoscopes of different types according to a difference in an observation part, a difference in spectral characteristics of a color separation optical system such as a color chip filter included in an imaging device of each endoscope is obtained. Causes a difference in color reproducibility. Even if the observation target site is the same, a color separation optical system having various spectral characteristics is used depending on the type of the imaging device. Further, the color temperature of the illumination light supplied from the light source device to the endoscope also varies. In endoscopic observation, color reproducibility near red is particularly important.

Therefore, for example, Japanese Patent Application Laid-Open No. Sho 64-17621
In Japanese Patent Application Laid-Open No. Hei 6-335449, a storage means is provided in the endoscope for storing information of a correction value for a deviation of the sensitivity or optical characteristic of the imaging device provided in the endoscope, and this information is transmitted from the endoscope. A configuration in which color correction such as white balance correction or the like suitable for a connected endoscope is performed by the video signal processing device by being provided to the video signal processing device is shown. In Japanese Patent Application Laid-Open No. 64-86934, information indicating spectral characteristics of color filters provided in a sequential light source device is supplied from the light source device to a video signal processing device, so that white balance correction suitable for the light source device is performed. And the like are shown.

In Japanese Patent Application Laid-Open Nos. 6-105803 and 6-105804, a color signal is obtained from an image pickup signal obtained by an image pickup apparatus, and a predetermined hue region to be corrected is detected based on the color signal. 1 shows a configuration for performing color correction on a predetermined hue. According to this configuration, the color near red and magenta hues, which occupy most of the color components of the subject in the body, is corrected to improve the color reproducibility. It is possible to determine blood and the like.

[0009]

However, the prior art disclosed in JP-A-64-17621, JP-A-6-335449 and JP-A-64-86934 discloses an image pickup device for an endoscope and a light source device. When the endoscope or the light source device is not provided with means for storing characteristic information indicating characteristics and transmitting the information to the video signal device device, color correction according to the characteristics of the imaging device or the light source device is performed on the video signal. The means to be performed in the processing unit was not shown. Further, when an endoscope or a light source device having a different procedure for transmitting characteristic information to the video signal processing device is connected to the video signal processing device, color correction according to the characteristics of the imaging device or the light source device is performed. No means to do so was indicated. Also, Japanese Patent Application Laid-Open No. 64-17621
JP-A-6-335449 and JP-A-64-869.
No. 34 discloses no means for performing color correction on a desired hue region. Also, Japanese Patent Application Laid-Open No. 6-105803
And JP-A-6-105804 do not disclose means for performing color correction in accordance with the characteristics of the imaging device and the light source device. The present invention has been made in view of the above circumstances, and even when an imaging device and a light source device having different color characteristics are used, the imaging device and the light source are not changed without changing the configurations of the endoscope and the light source device. It is an object of the present invention to provide a video signal processing device that performs color correction according to a difference in color characteristics of a device and performs color correction in a desired hue region to improve color reproducibility of an obtained video signal. I do.

[0010]

In order to achieve the above object, a video signal processing apparatus according to the present invention comprises: a first video signal for obtaining a first video signal from an image signal obtained by capturing a subject image by an imaging device; Signal processing means, second video signal processing means for performing at least white balance correction processing on the first video signal to obtain a second video signal, and processing the first video signal or the second video signal. Hue detection means for detecting whether or not the hue is within a predetermined hue range; color correction amount calculation means for calculating a color correction amount for the second video signal according to an output of the hue detection means; A third video signal processing unit for performing a color correction process on the second video signal in accordance with the correction amount.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 9 relate to a first embodiment of the present invention. FIG. 1 is an explanatory view showing a configuration of an endoscope apparatus, and FIG. 2 is an explanatory view showing a configuration of an imaging apparatus. FIG. 3 is a block diagram showing a configuration of a video signal processing device, FIG. 4 is a block diagram showing a configuration of a color difference signal synchronizing circuit, FIG. 5 is a block diagram showing a configuration of a white balance correction circuit, and FIG. FIG. 7 is a block diagram showing the configuration of the circuit, FIG. 7 is a time chart showing the time series of pixel signal components included in the image pickup signal, FIG. 8 is a time chart showing the operation of the color difference signal synchronizing circuit, and FIG. It is a time chart which shows an effect.

As shown in FIG. 1, an endoscope apparatus 1 according to the present embodiment includes, for example, an endoscope 2 which is inserted into a body cavity to capture a subject image and obtain an image signal, A light source device 3 for supplying, for example, white illumination light, a video signal processing device 4 for obtaining a video signal that can be displayed on a monitor from an imaging signal obtained by the endoscope 2, and a video signal obtained by the video signal processing 4. And a monitor device 5 for projecting the image.

The endoscope 2 includes, for example, an insertion portion 11 to be inserted into a body cavity, an operation portion 12 provided at a base end side of the insertion portion 11 for gripping and operating the endoscope 2, A light guide 13 that is inserted through the endoscope 2 and extends, for example, from the operation unit 12 and guides illumination light supplied from the light source device 3 to the tip of the insertion unit 11; and a light guide 13 provided at the tip of the insertion unit 11. A light distribution optical system 14 for distributing illumination light guided by the light guide 13 toward a subject, an imaging optical system 15 provided at a tip of the insertion unit 11 for forming a subject image, The imaging apparatus 16 includes an imaging device 16 that captures a subject image formed by the imaging optical system 15 and obtains an imaging signal.

As shown in FIG. 2, the single-panel simultaneous imaging device 16 is provided, for example, with a CCD 16a for capturing an image of a subject and obtaining an imaging signal, and on the optical path of the subject image in front of the CCD 16a. And a color chip filter 16b for limiting the transmission color of each pixel. Color chip filter 16 according to the present embodiment
b is M for each pixel of the CCD 16a.
This is a complementary color filter that transmits any of the colors g, Cy, Ye, and G. Further, the CCD 16a according to the present embodiment
Is configured to output an image signal that combines two lines of the CCD 16a into one line.

As shown in FIG. 3, the video signal processing device 4 includes a drive signal generation circuit 21 for generating a drive signal for driving the image pickup device 16 and a timing control for timing control of each part of the video signal processing device 4. A circuit 22, a preamplifier 23 for amplifying an image signal obtained from the imaging device 16, and an image signal amplified by the preamplifier 23.
A CDS circuit 24 that performs a DS (correlated double sampling) process to remove a reset noise component from an image signal and extract a video signal component, and converts a video signal obtained by the CDS circuit 24 from an analog signal to a digital signal. A /
A D / D conversion circuit 25, a luminance / color separation circuit 26 for separating a video signal output from the A / D conversion circuit 25 into a luminance signal YH and a color difference signal CR / CB, and a luminance / color separation circuit 26 Luminance signal YH and color difference signal CR / CB
And a black balance correction circuit 27 that removes noise included in an OB (optical black) period and outputs a luminance signal YH and a color difference signal CR / CB, and a luminance output from the black balance correction circuit 27. Signal YH
A delay circuit 28 that outputs a luminance signal YH in synchronization with the delay of another signal path, and a γ correction circuit 29 that performs γ correction processing on the luminance signal YH output from the delay circuit 28 An LPF 31 (low-pass filter) that removes a high-frequency component of the luminance signal YH output from the black balance correction circuit 27 and outputs a low-band luminance signal YL; and a color difference output from the black balance correction circuit 27 LPF 32 that removes high frequency components of signal CR / CB and outputs low-band color difference signal CR / CB
And the color difference signal CR / CB output from the LPF 32
A color difference signal synchronizing circuit 33 for synchronizing and spatially dividing two color difference signals CR and CB superimposed by time division on the luminance signal YL output from the LPF 31 and output from the color difference signal synchronizing circuit 33. Color difference signals CR, CB
Is input, and the R (red component) signal, the G (green component) signal and B
A color signal conversion circuit 34 for converting an image into a RGB format video signal comprising three color signals (blue components); and a white balance for performing a white balance correction process on the video signal obtained by the color signal conversion circuit 34. A correction circuit 35;
A gamma correction circuit 36 that performs gamma correction processing on the video signal obtained by the white balance correction circuit 35, a color correction circuit 37 that performs color correction processing on the video signal obtained by the gamma correction circuit 36, An RGB format video signal output from the color correction circuit 37 is input, and color difference signals RY,
A color signal conversion circuit 38 for converting the color difference into RB, and a chroma suppression circuit 39 for performing a chroma suppression process on the color difference signals RY and RB obtained by the color signal conversion circuit 38.
And the color difference signals RY and RB output from the chroma suppress circuit 39 are superposed in a dot-sequential manner, that is, in a time-division manner.
A dot-sequencing circuit 40 for converting to a video signal in the form of "Y: U: V = 4: 2: 2"; a luminance signal YH output from the gamma correction circuit 29; It has a digital encoder 41 for inputting a signal and converting it into a video signal that can be displayed on a monitor.

As shown in FIG. 4, the color difference signal synchronizing circuit 33 stores the input color difference signals CR / CB temporarily and delays them by 1H period (horizontal scanning period).
1 and the color difference signal CR /
A line memory 52 for further delaying CB by 1H, a color difference signal CR / CB as an input signal and the line memory 5
2, an averaging circuit 53 for calculating an average value of the color difference signals CR / CB output from each pixel, and the timing control circuit 22 controls the timing of the color difference signals CR / CB output from the averaging circuit 53. A selection circuit 54 for alternately obtaining a color difference signal CR every 1H from the CB and the color difference signal CR / CB output from the line memory 51, and a timing control circuit 22 controls the timing and outputs the output from the averaging circuit 53. From the color difference signal CR / CB and the color difference signal CR / CB output from the line memory 51.
A selection circuit 55 for alternately obtaining a color difference signal CB for each H is provided. The color difference signal synchronizing circuit 33 synchronizes the color difference signals CR and CB superimposed on the line-sequential color difference signals CR / CB in a time-division manner and spatially divides them. The averaging circuit 53 outputs a color difference signal C as an input signal.
R / CB and color difference signal C output from line memory 52
An adder 53a for adding R / CB;
and a divider 53b for halving the signal obtained at a.

As shown in FIG. 5, the white balance correction circuit 35 includes average values RAVE, GA of the R, G, and B signals constituting the input video signal.
Average value calculation circuit 61 for calculating VE and BAVE, and average values RAVE and GAV obtained by the average value calculation circuit 61
A correction value calculation circuit 62 that calculates white balance correction values RWB and BWB for each of the R and B signals based on E and BAVE, and a white balance correction value RWB and BWB for the input R and B signals, respectively. The circuit includes multipliers 63 and 64 for multiplying and performing white balance correction, and a latch circuit 65 for holding white balance correction values RWB and BWB.

As shown in FIG. 6, the color correction circuit 37
Is a hue characteristic determination circuit that obtains hue characteristic information indicating hue characteristics resulting from the characteristics of the imaging device 16 and the light source device 3 based on the white balance correction values RWB and BWB obtained by the white balance correction circuit 35. A correction amount calculating circuit 72 for calculating a color correction amount based on the input video signal and the hue characteristic information; and performing an output by performing color correction on the input video signal according to the hue characteristic information and the color correction amount. It is configured to have a correction operation circuit 73 that performs the operation.

The hue characteristic determination circuit 71 includes a comparison circuit 71a for comparing the white balance correction amount RWB and the white balance correction amount BWB, and outputs the comparison result as hue characteristic information. Has become.

The correction amount calculating circuit 72 calculates a basic correction amount from an input video signal.
And a selector circuit for selecting again either the basic correction amount obtained by the basic correction amount calculation circuit 72a or the zero value as the basic correction amount according to the sign of the basic correction amount obtained by the correction amount calculation circuit 72a. 72b, a coefficient calculation circuit 72c for calculating a correction coefficient for the basic correction amount output from the selection circuit 72b according to the hue characteristic information, and a coefficient calculation for the basic correction amount obtained by the selection circuit 72b. It has a multiplier 72d that obtains a color correction amount by multiplying the correction coefficient obtained by the circuit 72c. The coefficient calculation circuit 72c includes, for example, an LUT 72ca (lookup table) that is a storage unit that outputs the correction coefficient as data by inputting the hue characteristic information as an address.

The correction operation circuit 73 includes a selection circuit 73a for selecting which of the G signal and the B signal constituting the input video signal is to be corrected in accordance with the hue characteristic information; An adder 73b for performing correction by adding the color correction amount obtained by the correction amount calculation circuit 72 to the color signal selected by the selection circuit 73a; and an adder 73b according to the hue characteristic information. A selection circuit 73c that selects any one of the output signal and the G signal input to the color correction circuit 37 and outputs the selected signal as a G signal.
And a selection circuit 73d for selecting any one of the signal output from the adder 73b according to the hue characteristic information and the B signal input to the color correction circuit 37 and outputting the selected signal as a B signal. It is configured to have.

Next, the operation of the present embodiment will be described. Illumination light emitted from the light source device 3 is applied to a subject via the light guide 13 and the light distribution optical system 14 of the endoscope 2. Then, a subject image from the subject irradiated with the illumination light is formed on the light receiving surface of the CCD 16a via the imaging optical system 15 and the color chip filter 16b of the imaging device 16. At this time, the color chip filter 16b is
For each pixel on the light receiving surface 16a, as shown in FIG.
Transmits any one of g, Cy, Ye, and G color components.

CCD 16a on which a subject image is formed on a light receiving surface
Is driven by a drive signal from the drive signal generation circuit 21, photoelectrically converts a subject image, and outputs an imaging signal. At this time, the CCD 16a simultaneously reads out and adds the charges of two vertically adjacent pixels on the light receiving surface, and outputs the added signal corresponding to one pixel of the imaging signal as shown in FIG. . That is, the CCD 16a is
Two lines on the light receiving surface are simultaneously read and two-line simultaneous reading corresponding to one line of the imaging signal is performed. And C
The imaging signal output from the CD 16a is provided to the video signal processing device 4.

The image pickup signal supplied to the video signal processing device 4 is subjected to predetermined gain adjustment by the preamplifier 23,
This is supplied to the DS circuit 24. The CDS circuit 24 performs a correlated double sampling process on the given image signal to remove reset noise included in the image signal and extract a video signal component. And this video signal is A /
The signal is converted into a digital signal by the D conversion circuit 25 and supplied to the luminance / color separation circuit 26.

Then, the luminance / color separation circuit 26 separates the applied video signal into a luminance signal YH and a color difference signal CR / CB. At this time, the luminance signal YH corresponding to the n-th line of the imaging signal is obtained by adding the signal values of horizontally adjacent pixels included in the imaging signal. For example, FIG.
The luminance signal of the n-th line of the imaging signal shown in FIG.
1) The luminance signal of the line is obtained by (Equation 1) and (Equation 2), respectively. R, G, and B represent signal levels of a red component, a green component, and a blue component, respectively, included in the video signal.

YH = (Mg + Ye) + (G + Cy) (Equation 1) = 2R + 3G + 2B YH = (Mg + Cy) + (G + Ye) (Equation 2) = 2R + 3G + 2B Further, the color difference signal CR / CB is included in the imaging signal. It is obtained by subtracting the signal value of the matching pixel. For example,
The color difference signal C corresponding to the n-th line of the imaging signal shown in FIG.
R / CB and color difference signal C corresponding to the (n + 1) th line
R / CB is obtained by (Equation 3) and (Equation 4), respectively. The color difference signal CR / CB is obtained by dividing the color difference signal CR obtained by (Equation 3) and the color difference signal CB obtained by (Equation 4) from:
These are line-sequential color difference signals superimposed alternately in a time-division manner for each line.

CR / CB = (Mg + Ye) − (G + Cy) (Equation 3) = 2R−G = CR CR / CB = (Mg + Cy) − (G + Ye) (Equation 4) = 2B−G = CB Luminance / Color The luminance signal YH and the color difference signal CR / CB obtained by the separation circuit 26 are
Black balance correction processing is performed so that the signal level in the B (optical black) period becomes 0. Then, the luminance signal YH subjected to the black balance correction processing is supplied to the delay circuit 28 and the LPF 31, and the color difference signal CR / CB subjected to the black balance processing is supplied to the LPF 32.

Luminance signal YH applied to delay circuit 28
Is delayed to match the timing with other signals,
The γ correction circuit 29 performs γ correction processing corresponding to the non-linear characteristic of the picture tube of the monitor device 5 and supplies the result to the digital encoder 41. On the other hand, the luminance signal YH supplied to the LPF 31 is subjected to a predetermined band limitation, output as a low-band luminance signal YL, and supplied to the color signal conversion circuit 34.

The color difference signal C supplied to the LPF 32
The R / CB is subjected to a predetermined band limitation and supplied to the color difference signal synchronizing circuit 33 as a low band color difference signal CR / CB. As shown in FIGS. 4 and 8, the color difference signal synchronizing circuit 33 obtains a signal obtained by delaying the color difference signal CR / CB by 1H period (horizontal scanning period) and 2H period by the line memories 51 and 52. Then, the input color difference signal CR
An average value is obtained by the averaging circuit 53 from the color difference signal CR / CB delayed by 2H period with respect to / CB, thereby performing vertical filtering. And the averaging circuit 5
3 and the output signal from the line memory 51 are supplied to the selection circuit 54 at the timing shown in FIG.
Are alternately selected every 1H, and the color difference signal CR is extracted. Similarly, the selection circuit 55 extracts the color difference signal CB. The color difference signal C thus synchronized
R and CB are provided to the color signal conversion circuit 34.

The luminance signal YL and the color difference signals CR and CB applied to the color signal conversion circuit 34 are subjected to an array operation shown in (Equation 5), and a low-band R (red component) signal and a G (green component)
A video signal composed of three color signals of a signal and a B (blue component) signal is obtained. Note that K11 to K33 in (Equation 5) are
The coefficient is set according to the spectral sensitivity characteristic of the CCD 16a and the color temperature characteristic of the illumination light.

[0031] At this time, the luminance signal Y given to the color signal conversion circuit 34
Since the signal value of L takes a positive value and the signal values of the color difference signals CR and CB take positive and negative values, the signal values of the signals R, G and B obtained by (Equation 5) are positive and negative values. Take. Therefore, for example, according to the setting by the operator, either the case where the negative component of the video signal obtained by (Equation 5) is clipped or the case where the clipping is not performed is selected. Here, if the clipping process is not performed on the negative component of the video signal, when a high-saturation, for example, strong red subject image is captured, the expression range of the G component and the B component other than the R component is widened and the color resolution is increased. Further, when the clipping process is performed on the negative component, the noise component included in the negative component of the video signal is removed in the dark part where the color signal level is low, and the dark part noise is improved. The RGB format video signal obtained by the color signal conversion circuit 34 is supplied to a white balance correction circuit 35.

Then, in the white balance correction circuit 35, the R signal and the G signal given by the average value calculation circuit 61 are given.
Average values RAVE, G of the respective signal values of the signal B and the signal B
AVE and BAVE are calculated. The calculation of the average value is performed for a predetermined range of the image by the control signal from the timing control circuit 22 at the time of white imaging.
The range in which the average value is calculated is preferably
The vicinity of the center of the screen where the light distribution unevenness of the illumination is small is set. Then, the correction value calculating circuit 62 calculates the obtained average value R
The white balance correction value RWB for the R signal and the white balance correction value BWB for the B signal are obtained by performing the operations shown in (Equation 6) and (Equation 7) on AVE and GAVE.

RWB = (GAVE) / (RAVE) (Equation 6) BWB = (GAVE) / (BAVE) (Equation 7) The obtained white balance correction values RWB and BWB are calculated by multipliers 63 and 64, respectively. , R signal and B signal, and the corrected R ′ signal and B ′ signal are obtained as shown in (Equation 8) and (Equation 9). The R ′ signal and B ′ signal obtained here are output from the white balance correction circuit 35 as an R signal and a B signal, respectively.
The input G signal is output from the white balance correction circuit 35 without correction.

R ′ = R × RWB = R × (GAVE) / (RAVE) = G (Equation 8) B ′ = B × BWB = B × (GAVE) / (BAVE) = G (Equation 9) When the operations shown in Expressions 8) and 9 are performed on the R signal and the B signal, the ratio of the R signal, the G signal, and the B signal at the time of white imaging becomes 1: 1: 1, and the white balance Correction processing is performed. Further, the obtained white balance correction value R
WB and BWB are output from the white balance correction circuit 35 while being held by a latch circuit 65 controlled by, for example, a vertical synchronization signal.

The video signal that has been subjected to the white balance correction processing is subjected to γ correction by the γ correction circuit 36 and is supplied to the color correction circuit 37.

In the color correction circuit 37, the hue characteristic determination circuit 7
By using 1, the hue characteristic information is obtained based on the white balance correction amounts RWB and BWB given from the white balance correction circuit 35. In the present embodiment, the hue characteristic information DETa is obtained by the comparison circuit 71a.
When WB <BWB, DETa = 0, and RWB>
In the case of BWB, DETa = 1. Here, the hue characteristic information DETa includes the white balance correction amounts RWB, B
This is information indicating the magnitude relationship of WB, that is, information indicating the magnitude of the correction amount for the R signal and the B signal in the white balance correction circuit 35, that is, the magnitude relationship of the gain.

When the value of the hue characteristic information DETa is 0, that is, when RWB <BWB, the gain for the R signal is large, and the B signal output from the color signal conversion circuit 34 and the R signal are output.
In a state where the relationship with the signal is B <R, the color characteristics such that the R component becomes strong are determined by the imaging device 16 and the light source device 3.
Is presumed to have a tendency. For example, between a xenon lamp and a halogen lamp generally used as the light source lamp of the light source device 3, the halogen lamp has a lower color temperature and a stronger red component. The value of the characteristic information DETa is 0
It tends to be.

When the value of the hue characteristic information DETa is 1, that is, when RWB> BWB, the relationship between the B signal and the R signal output from the color signal conversion circuit 34 is R <B. It is estimated that the imaging device 16 and the light source device 3 tend to have color characteristics that increase the color temperature. For example, when a xenon lamp is used as the light source lamp of the light source device 3, the value of the hue characteristic information DETa tends to be 1.

The hue characteristic information DETa obtained by the hue characteristic determination circuit 71 is given to a correction amount calculation circuit 72 and a correction operation circuit 73.

On the other hand, the correction amount calculation circuit 7 of the color correction circuit 37
In 2, the basic correction amount calculation circuit 72a performs the operation shown in (Equation 10) based on the supplied R signal, G signal, and B signal to obtain the basic correction amount C, which is provided to the selection circuit 72b. . In Equation (10), p and q are coefficients for adjusting the basic correction amount C according to the hue range. In the present embodiment, for example, p = q = 1 I have.

C = R− (p × G + q × B) (Equation 10) Then, the selection circuit 72 b determines whether the basic correction amount C or the 0 value is the basic correction amount by the condition judgment shown in (Equation 11). C is given to the multiplier 72d.

(Output of the selection circuit 72b) = 0 (when C <0) = C (when C> 0) (Expression 11) In Expression 10, when p = q = 1, the selection circuit The basic correction amount C obtained in 72b has the following characteristics. That is, first, when the subject image is the primary red color, G = B =
Since it is 0, C = R. When the subject image is yellow, R = G, B = 0, and C = 0. Also,
When the subject image is magenta, R = B and G = 0.
That is, when the color of the subject image is close to the red primary color, C becomes the maximum value R, and the value of C decreases as approaching yellow or magenta. Therefore, the value of C decreases as the levels of G and B increase, and conversely, the value of C increases as the values of G and B decrease and approach the red primary color.

The basic correction amount C obtained in this manner is multiplied by a correction coefficient r obtained by a coefficient calculation circuit 72c by a multiplier 72d, and the corrected color correction is obtained as shown in (Equation 11a). The quantity C 'is obtained. At this time, the LUT 72ca of the coefficient calculation circuit 72c outputs the correction coefficient r in accordance with the value of the hue characteristic information DETa obtained by the hue characteristic determination circuit 71, so that the LUT 72ca according to the color characteristics of the imaging device 16 and the light source device 3. The obtained color correction amount C ′ is obtained.

C ′ = r × C (Equation 11a) On the other hand, the correction operation circuit 73
Which color signal of the G signal or the B signal is to be subjected to color correction is selected by a, 73c, and 73d, and the color signal not subjected to color correction is output as it is without any processing. You. At this time, the selection circuits 73a, 73c, 73
d is the hue characteristic information DET from the hue characteristic determination circuit 71.
When it is determined that the hue in the vicinity of red is to be corrected in the yellow direction based on a, the G signal is selected as a color correction target in order to increase the G signal, and conversely, it is determined that the hue in the magenta direction should be corrected. At times, the B signal is selected as a target of color correction in order to increase the B signal. Selection circuit 73
The color signals selected as the color correction targets in a, 73c, and 73d are subjected to color correction by adding the color correction amount C ′ by the adder 73b, and output from the color correction circuit 37.

In the color correction circuit 37 operating as described above, for example, when a desired hue near red is detected,
Fine adjustment of the hue in the desired hue region is performed.

The RG subjected to color correction by the color correction circuit 37
The video signal in the B format is subjected to the array operation shown in (Equation 12) by the color signal conversion circuit 38, and the color difference signals RY, B-
The signal is converted to Y and supplied to the chroma suppress circuit 39.

[0047] Note that the luminance signal Y obtained by (Equation 12) may be generally used in chroma suppression processing, but as in the present embodiment, a low-bandwidth signal generated in a stage preceding the color signal conversion circuit 38 is used. In the configuration in which the luminance signal YL is given to the chroma suppress circuit 39, the luminance signal Y shown in (Equation 12) is not required, and therefore the luminance signal Y of (Equation 12) is generated in the color signal conversion circuit 38 of the present embodiment. do not do.

Generally, in the array operation shown in (Equation 12), the following coefficients are used.

L11 = 0.299, L11 = 0.587, L11 = 0.114, L21 = 0.701, L22 = −0.587, L23 = −0.114, L31 = −0.299, L32 = −0.587, L33 = 0.886 In addition, ITU-R6, a studio standard recently established,
According to 01, the following coefficients are recommended to provide a margin for the signal level.

L11 = 0.299, L11 = 0.587, L11 = 0.114, L21 = 0.500, L22 = −0.419, L23 = −0.081, L31 = −0.169, L32 = -0.331, L33 = 0.500 In the chroma suppress circuit 39, chroma suppress processing or the like for preventing coloring at high luminance by referring to the luminance signal YL of the low band is performed by the color difference signals RY and BY. Is applied to

The color difference signals RY and BY output from the chroma suppress circuit 39 are converted by the dot sequential circuit 40 into color difference signals as shown in FIG. 9 in order to conform to the ITU-R601 standard which is a studio standard. The signals RY and BY are superimposed in a time-division manner to be dot-sequential, and "Y: U: V = 4: 2:
2 ”format video signal and the digital encoder 4
Given to 1.

The video signal supplied from the gamma correction circuit 29 and the dot sequential circuit 40 to the digital encoder 41 is converted into a general format video signal that can be output to the monitor device 5, for example, a composite video signal or a component signal. Is output to the monitor device 5.

As described above, according to the present embodiment, the color correction is performed by judging the hue characteristics caused by the color characteristics of the image pickup device and the light source device using the white balance correction amount. Color correction corresponding to an imaging device and a light source device having color characteristics can be performed. Further, since the difference in color characteristics between the imaging device and the light source device is determined based on the white balance correction amount obtained in the video signal processing device, the configuration of the endoscope and the light source device does not change. Further, color correction can be performed in a desired hue region, for example, in the vicinity of red. Therefore, according to the present embodiment, even when an imaging device and a light source device having different color characteristics are used, the color characteristics of the imaging device and the light source device can be changed without changing the configurations of the endoscope and the light source device. By performing color correction according to the difference and performing color correction in a desired hue region, the effect of improving the color reproducibility of the obtained video signal can be obtained.

(Second Embodiment) FIGS. 10 and 11 relate to a second embodiment of the present invention. FIG. 10 is a block diagram showing a configuration of a color correction circuit, and FIG. FIG. In the second embodiment, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted. In addition, the same points as those in the first embodiment will be described. The description of is omitted.

As shown in FIG. 10, in the present embodiment,
In place of the color correction circuit 37 (see FIG. 3) of the first embodiment, the color difference signals RY and BY output from the color signal conversion circuit 38 are subjected to color correction processing to perform a chroma suppression circuit 39. A color correction circuit 101 is provided. In the present embodiment, the video signal output from the gamma correction circuit 36 (see FIG. 3) is provided to the color signal conversion circuit 38 (see FIG. 3). Other configurations are the same as those in the first embodiment.

The color correction circuit 101 according to the present embodiment
According to the white balance correction amounts RWB and BWB obtained by the white balance correction circuit 35, the color difference signals RY,
A correction amount calculating circuit 102 for obtaining correction coefficients Kr and Kb for BY, and determining whether or not the hue area of the video signal is a desired hue area based on the color difference signals RY and BY An area discriminating circuit 103 for outputting characteristic information DETb, and correction coefficients Kr and Kb obtained by the correction amount calculating circuit 102
And the hue characteristic information D obtained by the area determination circuit 103
A correction operation circuit 104 for correcting the color difference signals RY and BY according to ETb is provided.

The correction amount calculation circuit 102 inputs the white balance correction amount RWB as an address,
Look-up table 102a for obtaining correction coefficient Kr for color difference signal RY, and white balance correction amount BWB
Is input as an address to obtain a correction coefficient Kb for the color difference signal BY.
Is configured.

The correction operation circuit 104 outputs the color difference signal R-
A multiplier 111 that obtains a color correction amount for the color difference signal RY by multiplying Y by the correction coefficient Kr, and a multiplier 112 that obtains a color correction amount for the color difference signal BY by multiplying the color difference signal BY by the correction coefficient Kb. A selection circuit 113 for selecting one of the color correction amount obtained by the multiplier 111 and the zero value in accordance with the hue characteristic information DETb; and a color correction amount obtained by the multiplier 112. A selection circuit 114 for selecting any one of the 0 values according to the hue characteristic information DETb, and the color correction amounts obtained by the selection circuits 113 and 114 are respectively applied to the color difference signals RY and BY. It has adders 115 and 116 for performing color correction by adding.

Next, the operation of the present embodiment will be described. In this embodiment, the description of the operation common to the first embodiment will be omitted. LU of the correction amount calculation circuit 102
T102a and 102b are color difference signals RY and BY corresponding to the white balance correction amounts RWB and BWB, respectively.
Output the correction coefficients Kr and Kb with respect to. The correction coefficients Kr and Kb are multiplied by the color difference signals RY and BY by the multipliers 111 and 112, respectively, to obtain a color correction amount. On the other hand, the area determination circuit 103 outputs the color difference signal R-
By inputting Y and BY, it is determined whether or not the hue region is within a desired range by using a conditional expression shown in (Expression 13). In addition,
α and β are set values indicating boundaries of a desired range.

R−Y> α, BY−β (Equation 13) In this embodiment, α = β = 0 is set.
The hue range that satisfies this condition is indicated by the hatched portion in FIG. When the conditional expression shown in (Equation 13) is satisfied, that is, when the hue is in the range indicated by the hatched portion in FIG. 11, the area determination circuit 103 sets the value of the hue characteristic information DETb to DETb = 1, for example. Is output, and if not satisfied, DET
b = 0 is output.

When the hue characteristic information is DETb = 1, the selection circuits 113 and 114 respectively operate the multiplier 1
The color correction amounts obtained in steps 11 and 112 are selected, and when the hue characteristic information is DETb = 0, a value of 0 is selected. The adders 115 and 116 perform color correction by adding the color correction amounts obtained by the selection circuits 113 and 114 to the color difference signals RY and BY respectively. Therefore, in the color correction circuit 101, when the hue is in the range of the hatched portion in FIG. 11, the color difference signals (RY) ′ and (BY) ′ are calculated by the equations (14) and (15). And are output as color difference signals RY and BY, respectively.

(R−Y) ′ = (R−Y) + Kr × (B−Y) (Equation 14) (B−Y) ′ = (B−Y) + Kb × (R−Y) (Equation 15) According to the above-described processing, for example, a color correction in accordance with a color variation tendency is performed on a color tone near red.

As described above, according to the present embodiment, similarly to the first embodiment, even when an imaging device and a light source device having different color characteristics are used, the endoscope and the light source can be used. The color reproduction is performed according to the difference in the color characteristics of the imaging device and the light source device without changing the configuration of the light source device, and the color correction is performed in a desired hue region, so that the color reproduction of the obtained video signal is performed. The effect that the property is improved is obtained.

(Third Embodiment) FIGS. 12 and 13 relate to a third embodiment of the present invention, and FIG. 12 is an explanatory view showing the appearance of a video signal processing apparatus. FIG. 12B is a rear view of the video signal processing device, and FIG. 13 is a block diagram illustrating a configuration of a correction amount calculation circuit. Note that, in the present embodiment, the same reference numerals are given to portions configured substantially the same as in the first embodiment, description thereof will be omitted, and the present embodiment will be described in common with the first embodiment. The description of the points is omitted.

As shown in FIG. 12, the video signal processing device 4 according to the present embodiment has a switch 201 on the back for selecting the type of light source used in the light source device 3 (see FIG. 1). are doing. For example, the switch 201 can switch between a xenon lamp and a halogen lamp as the type of light source. The switch 20
1 may be used to switch the type of the imaging device 16 (see FIG. 1).

As shown in FIG. 13, in the present embodiment,
Coefficient calculation circuit 72 of color correction circuit 37 of the first embodiment
A correction amount calculation circuit 202 is provided in place of c (see FIG. 6). The correction amount calculation circuit 202 includes an LUT 202a that outputs a correction coefficient r to be applied to a multiplier 72d (see FIG. 6) as an 8-bit value, for example, in accordance with a signal from the switch 201.

Next, the operation of the present embodiment will be described. In this embodiment, the description of the operation common to the first embodiment will be omitted. The operator switches the switch 201 depending on the type of the light source lamp used for the light source device 3. Then, according to the type of light source lamp,
In accordance with the color characteristics of the light source device 3, the correction coefficient r is provided from the correction amount calculation circuit 202 to the multiplier 72d, and the color correction is performed by the color correction circuit 37 as in the first embodiment.

According to the present embodiment described above, similarly to the first embodiment, even when an imaging device and a light source device having different color characteristics are used, the endoscope and the light source device can be used. The color correction is performed according to the difference in the color characteristics of the imaging device and the light source device without changing the configuration, and the color correction in the desired hue region is performed, so that the color reproducibility of the obtained video signal is improved. The effect is obtained.

It should be noted that the correction amount calculation circuit 202
The correction amount calculation circuit 1 according to the second embodiment is provided in place of the coefficient calculation circuit 72c according to the second embodiment.
02 (FIG. 10) to output the correction coefficients Kr and Kb.

(Fourth Embodiment) FIG. 14 is a block diagram showing a configuration of a correction amount calculating circuit according to a fourth embodiment of the present invention. In this embodiment, the same reference numerals are given to the same components as those in the third embodiment, and the description thereof will be omitted. In addition, the points common to the third embodiment will be described. Is omitted.

As shown in FIG. 14, in the present embodiment,
Switch 201 of the third embodiment (see FIG. 12)
Is removed, and the correction amount calculating circuit 21 (see FIG. 13) of the third embodiment is replaced with the correction amount calculating circuit 21.
1 is provided. The correction amount calculation circuit 211 includes an LUT 211a that inputs, for example, an 8-bit correction condition signal provided from input means such as a keyboard (not shown) as an address and outputs a correction coefficient r. The correction condition signal is a signal that can identify the type of the light source device 3 (see FIG. 1) and the type of the imaging device 16 (see FIG. 1).
The greater the number of bits, the finer the gradation of color correction can be made.

Next, the operation of the present embodiment will be described. The operator gives the type of the light source device 3 and the type of the imaging device 16 using, for example, a keyboard (not shown). Then, for example, a correction coefficient r is output from the correction amount calculation circuit 211 in accordance with a correction condition signal corresponding to the type of the light source device 3 and the type of the imaging device 16, and the color correction circuit 37 is provided as in the third embodiment. Performs color correction.

According to the present embodiment described above, the same effects as in the third embodiment can be obtained. Further, compared with the third embodiment, the gradation of the correction coefficient when performing the color correction can be made finer.

The correction condition signal is not limited to being input from a keyboard (not shown), but may be input from other input means. The information for determining the type of the imaging device 16 includes information indicating the number of pixels of the CCD 16a (see FIG. 2) and information indicating the material of the color chip filter 16b. The information may include various information that can be used to correct the variation in color reproducibility that occurs. Further, a configuration may be adopted in which a correction condition signal is provided from the endoscope 2 to the video signal processing device 4 as necessary. At this time, a configuration may be adopted in which the correction condition signal is superimposed on the imaging signal. Further, the correction amount calculating circuit 211 may be used not only to provide the correction coefficient r of the first embodiment, but also to provide the correction coefficients Kr and Kb of the second embodiment. Then, the coefficients p and q in (Equation 10) of the first embodiment are used.
May be used to give the values of α and β in (Equation 13) of the second embodiment.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the invention. For example, in the above-described embodiment, a simultaneous imaging device and a light source device are used, but the present invention is not limited to this, and a sequential imaging device and a light source device may be used. Further, the CCD constituting the imaging device is not limited to a single-plate type. Further, the color chip filter is not limited to the complementary color filter, and may be a primary color filter. The circuit constituting the video signal processing device is not only implemented by a hardware circuit, but also by implementing a microprocessor that operates according to a control program stored in a storage unit such as a storage element, and achieves similar functions. You may. In addition, in a configuration in which the execution timing of the white balance correction process is manually given, the operator generally needs to give the execution timing of the white balance correction process every time the endoscope is replaced. Means may be provided to prevent the operator from forgetting the instruction to execute the white balance correction process by, for example, displaying a guidance display for invoking the execution to the operator on a monitor device, for example.

By the way, in general, there are various lighting environments such as brightness and color temperature of an examination room or the like in which an endoscope apparatus is used. If the illumination environment in which the endoscope device is used is various as described above, the image quality of a video signal obtained by the endoscope device varies due to the difference in the illumination environment. Accordingly, it is necessary for the operator to set the video signal processing device and the monitor device, and the operability is poor. Therefore, a video signal processing device that can improve operability when used in various lighting environments will be briefly described. That is, this video signal processing device includes a CdS for measuring an illumination environment such as ambient brightness and color temperature.
A photodetector configured with elements and the like is connected. Then, when using the endoscope device, by imaging the room with an imaging device provided in the endoscope, and operating a switch provided in the video signal processing device or the light detection device, by the light detection device, Ambient brightness, color temperature, and the like are measured, and information indicating the lighting environment is provided to the video signal processing device. Then, the video signal processing device:
Various setting values are set for performing correction processing such as color tone adjustment, contrast adjustment, and γ correction on the video signal according to the given illumination environment information. According to such a video signal processing device, the setting of the video signal processing device according to the lighting environment is performed by a simple operation, so that the operability when used in various lighting environments is improved.

[Supplementary Note] (Supplementary note 1-1) First video signal processing means for obtaining a first video signal from an imaging signal obtained by capturing an image of a subject with an imaging device; Second video signal processing means for performing at least white balance correction processing to obtain a second video signal, and the first video signal or the second video signal
Hue detection means for detecting whether the hue of the video signal is within a predetermined hue range, and color correction amount calculation means for calculating a color correction amount for the second video signal according to an output of the hue detection means And a third video signal processing means for performing a color correction process on the second video signal in accordance with the color correction amount.

(Additional Item 1-2) The video signal processing device according to additional item 1-1, wherein the imaging device is provided in an endoscope.

(Additional Item 1-3) In the video signal processing device according to additional item 1-1, the hue detecting means is configured to determine the first hue based on a white balance correction amount used in the white balance correction process. Is detected within the predetermined hue range.

(Additional Item 1-4) The video signal processing apparatus according to additional item 1-1, further comprising an input unit for inputting information indicating the predetermined hue range.

(Additional Item 1-5) Input means for inputting information to be referred to when the color correction amount calculating means calculates the color correction amount is provided.

(Additional Item 1-6) First image signal for obtaining a first video signal from an image signal obtained by imaging an object image by an image capturing apparatus
Video signal processing means, second video signal processing means for performing at least white balance correction processing on the first video signal to obtain a second video signal, and the first video signal or the second video signal Input means for inputting whether or not the hue of the signal is within a predetermined hue range; color correction amount calculating means for calculating a color correction amount for the second video signal according to information from the input means; According to the color correction amount, the second
And a third video signal processing means for performing a color correction process on the video signal.

(Additional Item 1-7) A first video signal for obtaining a first video signal from an imaging signal obtained by imaging an object image by an imaging device.
Video signal processing means, second video signal processing means for performing at least white balance correction processing on the first video signal to obtain a second video signal, and the first video signal or the second video signal Storage means for storing whether or not the hue of the signal is within a predetermined hue range; color correction amount calculation means for calculating a color correction amount for the second video signal according to information from the storage means; According to the color correction amount, the second
And a third video signal processing means for performing a color correction process on the video signal.

(Additional Item 1-8) A first video signal for obtaining a first video signal from an image pickup signal obtained by picking up an object image by an image pickup device.
Video signal processing means, second video signal processing means for performing at least white balance correction processing on the first video signal to obtain a second video signal, and information capable of identifying the color characteristics of the imaging device. Color correction amount calculation means for calculating a color correction amount for the second video signal based on the color correction amount, and third video signal processing means for performing color correction processing on the second video signal in accordance with the color correction amount A video signal processing device comprising:

(Additional Item 1-9) A first method for obtaining a first video signal from an image pickup signal obtained by picking up an object image by an image pickup device.
Video signal processing means, a second video signal processing means for performing at least white balance correction processing on the first video signal to obtain a second video signal, and identifying a color characteristic of illumination light supplied to the subject. Color correction amount calculating means for calculating a color correction amount for the second video signal based on possible information; and third color correction processing for performing a color correction process on the second video signal in accordance with the color correction amount. A video signal processing device comprising: video signal processing means.

[0086]

As described above, according to the present invention,
Even when an imaging device and a light source device with different color characteristics are used, color correction is performed according to the difference in the color characteristics of the imaging device and the light source device without changing the configuration of the endoscope and the light source device, In addition, by performing color correction in a desired hue region, an effect of improving color reproducibility of an obtained video signal can be obtained.

[Brief description of the drawings]

FIG. 1 to FIG. 9 relate to a first embodiment of the present invention, and FIG. 1 is an explanatory diagram showing a configuration of an endoscope apparatus.

FIG. 2 is an explanatory diagram illustrating a configuration of an imaging device.

FIG. 3 is a block diagram illustrating a configuration of a video signal processing device.

FIG. 4 is a block diagram illustrating a configuration of a color difference signal synchronization circuit.

FIG. 5 is a block diagram illustrating a configuration of a white balance correction circuit.

FIG. 6 is a block diagram illustrating a configuration of a color correction circuit.

FIG. 7 is a time chart illustrating a time series of a pixel signal component included in an image pickup signal.

FIG. 8 is a time chart showing the operation of the color difference signal synchronizing circuit.

FIG. 9 is a time chart showing the operation of the dot sequential circuit.

FIG. 10 and FIG. 11 relate to a second embodiment of the present invention, and FIG. 10 is a block diagram showing a configuration of a color correction circuit.

FIG. 11 is an explanatory diagram showing the operation of an area determination circuit.

12 and 13 relate to a third embodiment of the present invention, and FIG. 12 is an explanatory view showing the appearance of a video signal processing device, and FIG. 12 (A) is a front view of the video signal processing device. , FIG.
2B is a rear view of the video signal processing device.

FIG. 13 is a block diagram illustrating a configuration of a correction amount calculation circuit.

FIG. 14 is a block diagram illustrating a configuration of a correction amount calculation circuit according to a fourth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 endoscope device 3 light source device 4 video signal processing device 16 imaging device 35 white balance correction circuit 37 color correction circuit 101 color correction circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H040 BA00 CA04 GA02 GA05 GA06 4C061 AA01 AA02 AA04 AA29 BB02 CC06 DD03 LL02 MM05 NN01 NN05 QQ02 SS22 SS23 TT03 TT13 5C054 AA01 AA05 CA04 CC03 EE06 A01 EA01 EA01 EA01 AA03 BA01 CA05 DB02 EA14 EA16 EC05 EE03 EE04 GA00 GA01 GA02 GA05 HA01 KE05 KF05 KM02 KM06 KM11

Claims (1)

[Claims] A first video signal processing means for obtaining a first video signal from an imaging signal obtained by capturing an object image by an imaging device; and performing at least white balance correction processing on the first video signal. Second video signal processing means for obtaining a second video signal; hue detection means for detecting whether the hue of the first video signal or the second video signal is within a predetermined hue range; A color correction amount calculating unit that calculates a color correction amount for the second video signal according to an output of the hue detecting unit; and a color correction process that performs a color correction process on the second video signal according to the color correction amount. 3. A video signal processing device comprising: