JP2837912B2 - Color shift reduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to color shift reduction for reducing color shift when it is determined that an image signal input from a frame sequential imaging device has color shift. Related to the device.

[Prior Art] In recent years, an emission unit for illuminating light is provided on the distal end side of an elongated insertion portion,
An optical endoscope having a built-in image forming means for forming a subject image illuminated by the illuminating light emitting means has been put to practical use.

Recently, an electronic endoscope having a solid-state imaging device such as a CCD at the distal end of the insertion section has been put into practical use, and displays a subject image in color on a display or records a subject image on a recording device such as a VTR. , And can be easily reproduced.

In the above-mentioned electronic endoscope, a case where a plane sequential color imaging method is adopted in order to minimize an increase in the outer diameter of the distal end portion due to the solid-state imaging device accommodated in the distal end portion of the insertion section. There is.

This is a system in which a sequentially illuminated subject is sequentially illuminated with illumination light of different wavelength ranges, a sequentially illuminated subject is sequentially imaged by a monochrome image sensor, and these sequentially imaged image signals are combined to obtain one color image signal. It is.

In this method, a high-resolution color image can be obtained even with an image sensor having a small number of pixels than a color image sensor using an optical color separation filter, but a color image having a color shift when a subject moves. Will be played back.

For this reason, there is a conventional example in which a color shift detecting unit is provided and the color shift is corrected when the color shift is detected. in this case,
There is known a method of correcting an image in which a color shift has occurred by applying an average of the entire image.

[Problems to be Solved by the Invention] In the above conventional example, the average value of the color components of the entire image can be applied to the color shift occurrence portion regardless of the saturation around the color shift occurrence portion. If the saturation around the image is higher or lower than the average saturation of the entire image, there is a disadvantage that an unnatural image becomes very hard to see.

As a prior example related to the present invention, Japanese Patent Application Laid-Open No. 62-2810
No. 67 and JP-A-63-10886. JP-A-62-281067
In a color image processing apparatus that performs a predetermined color correction process on a color image signal, a human color is output by outputting the memory color for a hue in a color image signal that is close to a predetermined memory color hue, such as a skin color. Discloses a color image processing apparatus that performs color correction using a memory color that is preferable.

In Japanese Patent Application Laid-Open No. 63-10886, when performing color ghost processing caused by improper mounting of an image sensor in a plurality of image signals obtained by using a plurality of image sensors, pixel information is used for color designation during color separation. And an image processing apparatus that performs ghost correction by using the color code after color separation and color separation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described drawbacks of the conventional example, and has been made in view of the above-described embodiments. It is intended to provide a device.

[Means for Solving Problems and Operation] As shown in the conceptual diagram of FIG. 1, an input image signal from a frame-sequential imaging device is input to a color component extraction unit 2 included in a color misregistration reduction device 1. The color component of the input image signal is extracted by the color component extraction means 2 and input to the judgment color judgment means 3 and the color shift judgment means 4. The specific color discriminating means 3 discriminates specific color information and outputs a specific color discriminating signal to the color misregistration reducing means 5.
, And a color misregistration determination signal from the color misregistration determining means 4 is also input to the color misregistration reducing means 5. This color shift reducing means 5
Corrects a color misregistration portion of an input image signal with a specific color discrimination signal and a color misregistration discrimination signal, and outputs the corrected image as a color misregistration reduced image. In this case, since the color misregistration is not only determined by the color misregistration determining means 4 but also the specific color determination signal by the determination color determining means 3 is considered, the color misregistration reduced image is more natural. be able to.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to the drawings.

FIG. 2 shows a color misregistration reducing apparatus according to a first embodiment of the present invention.

As shown in FIG. 2, an input image signal from a frame-sequential imaging device (for example, see FIG. 7 described later) is input to a color component extraction unit 12 constituting a color misregistration reduction device 11 of the first embodiment.
The saturation r and the hue θ are extracted by the color component extraction unit 12. The saturation t is input to the saturation determination unit 13, the color shift determination unit 14, and the correction color unit 15, and the hue θ is input to the color shift determination unit 14 and the correction color unit 15.

The saturation determination unit 13 outputs a saturation determination signal indicating whether or not the input saturation r (signal) is equal to or higher than a specified arbitrary saturation. For example, it is possible to designate a colorless color (or a hue close to colorless) and output a chroma discrimination signal when the chroma is extremely low.

The output signal of the saturation determination unit 13 is input to the gate unit 16. Further, the color misregistration determining section 14 determines a color misregistration portion from the input saturation r and hue θ, and outputs the same to the gate section 16 as a color misregistration determination signal. The correction color section 15 generates a correction color (signal) for correction from the saturation r and the hue θ, and outputs it to one contact a of the switch 17. The correction color section 15 outputs, for example, an average color of one screen as a correction color.

The input image is applied to the other contact b of the switch 17. The switching of the switch 17 is controlled by a color misregistration determination signal output via a gate unit 16. For example, when the gate section 16 is closed, the switch 17
Is ON, and the input image is output as an output image via the switch 17. When the gate unit 16 is open and the color misregistration determination unit 14 outputs a color misregistration determination signal indicating that there is a color misregistration, the switch 17 is turned on as shown in FIG.
Then, a correction color signal of the correction color section 15 is output. Gate section 16
If the color misregistration determination unit 14 does not output a color misregistration determination signal indicating that there is a color misregistration even if is open, the switch 17 has the contact b turned ON.

In the gate section 16, the opening and closing of the gate where the color misregistration determination signal is output from the gate section 16 is controlled by the saturation determination signal. That is, when a color misregistration determination signal indicating that there is a color misregistration is output from the color misregistration determination unit 14 to the gate unit 16, the saturation determination unit 13 outputs a signal that normally opens the gate unit 16,
For example, if the color is colorless or colorless and the saturation is low, the gate of the gate unit 16 is controlled to be closed by the saturation determination signal, and the gate unit 16 is closed. The input image to be input, that is, the original image is output as it is.

When the input image is colorless or extremely low in saturation, by outputting the original image without switching to the correction color, it is possible to prohibit the colorless portion from being corrected with the average color, and to achieve a simple configuration. Thus, a natural image with reduced color misregistration can be obtained.

Note that the saturation determined by the saturation determination unit 13 is not limited to specifying colorless, and any saturation, such as when the saturation is extremely high, is possible. Further, the color shift reduction is switched by the switch 17, but another method may be used. For example, the mixture ratio between the correction color and the original image may be changed.

Although the saturation r and the hue θ are used, other color components,
For example, a color misregistration reducing apparatus can be configured by performing color misregistration determination using a color difference signal or the like.

FIG. 3 shows a color misregistration reducing device 21 according to a second embodiment of the present invention.

A color component extraction unit 12 extracts a saturation r and a hue θ from an input image signal from a frame sequential imaging device. The saturation r and the hue θ are determined by the color misregistration determination unit 14 and a plurality of correction color units,
For example, it is input to the first correction color section 22 and the second correction color section 23, and the saturation r is input to the saturation determination section 13 '.

The saturation determination unit 13 'outputs a saturation determination signal of, for example, a center value of saturation as a threshold value, a LOW level for a value less than this value, and a HIGH level for a value less than this value. The output is a first switch 24 as a correction color selection switch.
Is controlled.

The first correction color section 22 includes a light correction color corresponding to a light color,
That is, a first correction color signal is generated and output to the contact a of the first switch 24.

On the other hand, the second correction color section 23 generates a dark correction color corresponding to the dark color, that is, a second correction color signal, and outputs the signal to the contact b of the first switch 24.

The first switch 24 responds to the chroma discrimination signal, and when the chroma discrimination signal is at the LOW level, the first correction color becomes H level.
In the case of the IGH level, control is performed so that the second correction color is selected, and the output of the first switch 24 is output to the contact a of the second switch 25. An input image signal is supplied to the other contact b of the switch 25, and switching is controlled by an output signal of the color misregistration determination unit 14. That is, when there is no color shift, the contact b is selected. On the other hand, when there is a color shift determination signal indicating that there is a color shift, the contact a is switched on as shown in FIG. Therefore, when the color misregistration determination unit 14 determines that there is a color misregistration, the correction color is output as an output image for reducing the color misregistration via the second switch 25.
In this case, the first or second correction color section 22 or 23 is selected according to the saturation r of the original image, so that the image signal for which the color shift is reduced has a correction having a saturation corresponding to the saturation of the original image. Since a color signal is output, it is possible to obtain a color misregistration reduced image that is almost natural.

Although the second embodiment has been described as an example in which two types of correction colors are switched, it is necessary to determine the saturation by dividing the saturation into a greater number of stages, and to output by switching the various types of correction colors. Obviously, you can. In addition, a color misregistration reducing device can be configured using not only the saturation r and the hue θ but also other color components, for example, a color difference signal.

FIG. 4 shows a color misregistration reducing device 31 according to a third embodiment of the present invention.

The color component extraction unit 12 extracts the saturation r and the hue θ from the input image signal from the frame sequential imaging apparatus. Saturation r
And the hue θ are input to the color misregistration determination unit 14 and the correction color unit 15, and the saturation r is input to the saturation determination unit 13 ″.

The color misregistration determination unit 14 determines a color misregistration from the saturation r and the hue θ, controls switching of the switch 32, and outputs an input image as an output image when there is no color misregistration. On the other hand, if it is determined that there is color misregistration, switching is performed so that contact b is switched from contact b to contact a, and color misregistration is reduced so that a compensation color is output from the compensation color unit 15 through the saturation adjustment unit 33.

The saturation determining unit 13 ″ determines the saturation r, and determines the saturation r.
The saturation level control signal rc according to the
And controls the saturation of the correction color of the correction color unit 15 through the saturation adjustment unit 33. The saturation adjustment unit 33 controls the attenuation of the attenuator or the gain of the amplifier by the saturation level control signal rc with respect to the correction color generated by the correction color unit 15, for example, the color average of the screen, and the contact of the switch 32. output to a.

According to the third embodiment, by controlling the saturation of the correction color according to the saturation of the original image, a more natural image with reduced color shift can be obtained.

Note that the saturation determination unit 13 ″ may perform determination corresponding to one pixel, or may output a determination signal corresponding to the average of the peripheral portion of the target pixel.

In the case of digital, the saturation adjusting section 33 may generate correction color data corresponding to the saturation level control by using a ROM table.

Further, the color misregistration may be reduced by using other color components, such as a color difference signal, instead of the saturation r and the hue θ.

FIG. 5 shows a color misregistration reducing device 41 according to a fourth embodiment of the present invention.

The color component extraction unit 12 extracts the saturation r and the hue θ from the input image signal from the frame sequential imaging apparatus. Saturation r
And the hue θ, the color shift determination unit 14, the specific color determination unit 42,
It is input to the correction color section 15.

The color misregistration determination unit 14 determines a color misregistration from the saturation r and the hue θ, and outputs a color misregistration determination signal to the switch 17 via the gate unit 16. The specific color determination unit 42 determines whether or not the hue θ, hue θ, and saturation r of the input image correspond to the specified arbitrary color, and gates the specific color determination signal. Output to the unit 16. In the gate section 16, control is performed to gate the color misregistration determination signal output from the color misregistration determination section 14 in accordance with the specific color determination signal. That is,
When the color misregistration determining unit 14 outputs a color misregistration determination signal indicating that there is a color misregistration to the gate unit 16, when the specific color determining unit 42 determines that the color is a specific color, the gate is closed and it is determined that the color does not correspond to the specific color. In this case, the gate is opened, a color misregistration discrimination signal is supplied to the switching control terminal of the switch 17, and the switch 17 is switched so that the contact a is turned on, so that the corrected color is output instead of the original image.

Therefore, even if there is a color shift, if the specific color determination unit 42 determines that the color is the specific color, the correction with the correction color is prohibited, and the original image is output.

For example, the specific color determination unit 42 has a specific color set so that a demonstration image or the like in which a color bar or the like is displayed can be determined.
The correction color section 15 generates an average color of one screen, for example.

In this case, the color misregistration determination unit 14 determines that the color bar is a color misregistration portion when there is a color bar, and outputs a color misregistration determination signal to reduce the color misregistration of the portion with the correction color. Since the specific color is detected by the unit 42 and the gate of the gate unit 16 is closed, the inconvenience of correcting the color bar portion with the average color can be eliminated.

In this embodiment, an example has been described in which the correction is prohibited when the specific color is determined. However, it is also easy to detect the specific color and correct it together with the color misregistration determination signal. By detecting and correcting or prohibiting a specific color in this way, the effect of reducing color misregistration can be improved.

Note that the specific color may be not only one color but also multiple colors, and whether or not it changes over time may be included in the factor for determination.

Further, the present invention is not limited to the method of reducing the color misregistration using the saturation r and the hue θ, and may use another color component, for example, a color difference signal.

FIG. 6 shows a color misregistration reducing device 51 according to a fifth embodiment of the present invention.

The color component extraction unit 12 extracts the saturation r and the hue θ from the input image signal from the frame sequential imaging apparatus. Saturation r
And the hue θ, the color shift determination unit 14, the specific color determination unit 42,
It is input to the correction color section 15.

The color misregistration determination unit 14 determines a color misregistration from the saturation r and the hue θ, and outputs a color misregistration determination signal to the switch 17 via the gate unit 16. The specific color determination unit 42 determines whether or not the hue θ of the input image, the hue θ, and the saturation r correspond to the designated arbitrary color, and determines the area of the specific color determination signal. Output to the unit 52. The area discriminating section 52 counts the specific color discriminating signal, judges how much area the specific color discriminating signal occupies on one screen, or what proportion the one screen occupies. Output to 16. The gate unit 16 gates the color misregistration discrimination signal with this area discrimination signal, for example, if dark green occupies the entire screen, prohibits correction, and if dark red occupies the entire screen, enables correction. The gate opening / closing of the gate unit 16 is controlled.

Alternatively, the time occupying the entire screen may be counted and added to the judgment.

The correction color section 15 generates a correction color from the saturation r and the hue θ, and supplies the correction color to the contact a of the switch 17. The switch 17 outputs a color misregistration reduced image by switching between the correction color and the original image in accordance with the color misregistration determination signal gated by the gate unit 16.

By switching the switch 17 from the input image depending on whether or not correction is possible, a color misregistration reduced image can be obtained.

It should be noted that a color misregistration reducing device can be configured using not only the saturation r and the hue θ but also other color components, for example, a color difference signal.

FIG. 7 shows an electronic endoscope apparatus 71 provided with, for example, a first embodiment of the present invention.

As shown in FIG. 7, the endoscope imaging device 71 of the first embodiment
Is a frame sequential electronic scope 72 and this electronic scope 72
Processor with built-in field-sequential light source device 73 for supplying field-sequential illumination light and image processing (signal processing) circuit 74
75, and a display 76 for displaying a video signal output from the video processor 75 in color.

The electronic scope 72 has an elongated insertion section 77, and a wide operation section 78 is formed at the rear end of the insertion section 77.

A light guide for transmitting illumination light is provided in the insertion portion 77.
The light guide 79 is inserted through the universal cord 81 extended from the operation unit 78, and the connector 82 at the end of the universal cord 81 can be attached to the video processor 75.

By attaching the connector 82, the illumination light of the light source device 73 is supplied to the incident end face of the light guide 79.

That is, the white light of the lamp 83 passes through the rotating color filter 85 rotated by the motor 84, and is further applied to the incident end face of the light guide 79 through the condenser lens 86.

The rotating color filter 85 is provided with three fan-shaped openings in the circumferential direction, and the red, green, and blue color transmission filters are respectively provided.
87R, 87G, 87B are installed. Therefore, the light guide 79
, Light of each wavelength of red, green, and blue is sequentially supplied. Then, the light is transmitted by the light guide 79, and is further emitted from the emission end face attached to the distal end of the insertion section 77 to the subject 89 forward through the illumination lens 88. A subject 89 illuminated with illumination light via the illumination lens 88 is imaged on a CCD 92 disposed on the focal plane by an objective lens 91 attached to the tip. The CCD 92 performs photoelectric conversion and accumulates electric charges.

The drive signal output from the CCD drive circuit 94 of the video processor 75 is read out by applying the drive signal to the CCD 92 via the signal line 95, and is input to the video circuit 96 in the video processor 75 via the signal line 95. Then, signal processing is performed to generate standard video signals, for example, three primary color signals R, G, and B, and the three primary color signals R, G, and B are output from their output terminals.

The three primary color signals R, G, and B, that is, the signal obtained by synchronizing the frame-sequential color signals, are input to the color component extraction unit 12 of the color misregistration reducing device 11 of the first embodiment, and are also input to the switch 17. .

The saturation r and the hue θ are extracted by the color component extraction unit 12, and the saturation r is input to the saturation determination unit 13, and the saturation r and the hue θ are input to the color shift determination unit 14 and the correction color unit 15. . Saturation determination unit 13
Performs the saturation determination, and controls the gate opening and closing when the color misregistration determination signal 14 is supplied from the gate unit 16 to the switching control terminal of the switch 17.

The color correction color section 15 outputs, for example, an average of three primary color signals of one screen <
R>, <G>, and <B> are generated and output to the switch 17.

According to the device 71 having the first embodiment, for example, when it is determined that there is a color shift, the colorless or colorless and low-saturation portion is prohibited from being corrected with the average color. Mitigation can be performed.

It is also possible to directly take in the frame sequential signal of the CCD 92 to reduce the color shift.

[Effects of the Invention] As described above, according to the present invention, a color misregistration reducing unit that determines color misregistration from extracted color information and reduces color misregistration, and specifies saturation and the like from the extracted color information Since the color information detecting means is provided to control the color misregistration reducing operation of the color misregistration reducing means, the color misregistration part can be made a more natural color misregistration reduced image with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a principle diagram showing a conceptual configuration of the present invention, FIG. 2 is a configuration diagram of a first embodiment of the present invention, FIG. 3 is a configuration diagram of a second embodiment of the present invention, and FIG. FIG. 5 is a block diagram of a fourth embodiment of the present invention, FIG. 6 is a block diagram of a fifth embodiment of the present invention, and FIG. 7 is a block diagram of the first embodiment. FIG. 1 is a configuration diagram of an electronic endoscope apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Color misregistration reduction apparatus, 2 ... Color component extraction means 3, ... Specific color discrimination means 4, ... Color misregistration determination means 5, ... Color misregistration reduction means

Claims (1)

(57) [Claims] 1. A color component extracting means for extracting a color component from an input image from an image pickup apparatus of a frame sequential type, a color misregistration judging means for judging a color misregistration from the color component and outputting a color misregistration determination signal, A color misregistration reducing unit that outputs a color misregistration reduction signal for color misregistration reduction in accordance with the color misregistration determination signal, and determines specific color information from the color components to output a determination color determination signal;
A color misregistration reducing device that controls an operation of the color misregistration reducing means based on the color misregistration determination signal.