JP2690209B2 - Color shift prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to a plurality of different wavelength components.
The present invention relates to a still image color misregistration prevention apparatus in an apparatus that sequentially captures subject images in minutes .

[0002]

2. Description of the Related Art In recent years, a solid-state image pickup device such as a CCD is provided at the end of an endoscope, and the inside of a body cavity is sequentially illuminated with red, green, and blue light to take a color image of the inside of the body cavity. 2. Description of the Related Art An endoscope imaging apparatus that makes a diagnosis based on a displayed color image has been developed. In order to shoot one color image by this method, it is necessary to shoot three color component images. Therefore, it takes a long time, and the color shift of the image is likely to occur due to the movement of the subject or camera shake.

As means for preventing this color shift, Japanese Patent Application Laid-Open No. 61-71790 filed by the present applicant discloses a technique for correcting the color shift of an image based on the difference between images taken at different times by an image pickup means. There has been proposed a device that includes a detecting unit and controls the imaging speed of the imaging unit according to the output of the detecting unit. According to this method, the operation speed of the imaging unit changes according to the operation speed of the subject,
Even in the case of a fast-moving subject, color shift can be prevented from occurring.

[0004]

The color shift preventing means in the endoscope imaging device proposed in the above publication is designed to prevent color shift in a moving image, and observes a still image on a monitor device. In such a case, conventionally, when a still instruction is given to the endoscope imaging apparatus, the still operation of the imaging means is performed unconditionally based on the instruction to obtain a still image. Therefore, if a still instruction is given while the position of the subject and the endoscope tip is relatively moving, a color shift occurs in the still image. This color shift makes it difficult for the observer to overlook the lesion or the like because the original subject image is difficult to see.

[0005] In order to obtain a still image free from color misregistration, there is a problem that a complicated operation of repeating a still instruction and a still image cancellation until a still image free of color misregistration is obtained is required. . Further, when a color shift has occurred in a still image, a method of correcting the color shift in an image processing and removing the color shift has been proposed. However, not only is the apparatus large-scale, but it is not possible to correct the peripheral portion of the image. There were drawbacks.

The present invention has been made in order to solve the above problems in obtaining a still image in a conventional endoscope image pickup device and the like, and a still image having a simple structure and no color shift is provided. It is an object of the present invention to provide a color misregistration prevention device that can easily obtain the above.

[0007]

In order to solve the above problems, the present invention provides an image pickup means for sequentially picking up a subject image with a plurality of different wavelength components, and different wavelength components sequentially output from the image pickup means. Image memory means for respectively storing the image pickup signals, monitor means capable of displaying a moving image based on the output signal of the image memory means, and stillness indicating means for instructing the stillness of the moving image displayed on the monitor means. ,
A color shift detecting unit that detects a color shift amount of a captured subject image based on an image pickup signal that is output from the image pickup unit different for a predetermined period, and a color shift amount that is detected by the color shift detecting unit is used as a reference. Comparing means for discriminating that the amount is smaller than the color shift amount, and controlling the image memory means based on the output signal of the stillness indicating means and the output signal of the comparing means to make the moving image displayed on the monitor means stationary. A color misregistration prevention device is configured with the image stillness control means.

In the case of an endoscope, the subject is mainly a living body, and the subject is often moving due to the beating and breathing of the subject's heart, but there is a cycle of both beating and breathing, and the subject is stationary at a certain timing. Or you will have very little movement. Therefore, there is almost no color shift in the captured image at this point. In the present invention configured as described above,
Is an image pickup signal that is output from the image pickup means for a predetermined period differently.
Based on the
The amount of color shift of the captured subject image is detected, and the comparison means
The amount of color shift detected by the color shift detection means is used as a reference
It is determined that the amount is less than the color shift amount. And the moving image
Output signal of the stationary instruction means for issuing the stationary instruction of the
Based on the output signal of the stage
-The still image is obtained by stopping the moving image displayed on the means .

Thus, in order to obtain a still image with no color shift, a still image with little color shift can be obtained.
Then, the complicated operation of repeating the stationary instruction and the stationary cancellation is repeated.
Easily get color-shifted still images without the need
be able to.

[0010]

Embodiments will be described below. 1 and 2
2 is a block diagram showing an embodiment of a color misregistration prevention apparatus according to the present invention, FIG. 1 shows an electronic endoscope portion, and FIG.
Indicates the color misregistration prevention device portion. The terminals a and b in FIG. 1 are connected to the terminals a 'and b' in FIG. In FIG. 1 and FIG. 2, reference numeral 1 denotes an electronic endoscope, an objective lens 2 is arranged at a tip portion thereof, and an image pickup device 3 composed of a CCD or the like is provided at an image forming position thereof. 4
Is a light guide made of glass fiber or the like for introducing illumination light into a living body.

Reference numeral 5 denotes a color filter disk provided with transmission filters for red, green, and blue. The color filter disk 5 is rotatably arranged facing one end surface of the light guide 4, and is connected to a motor 6 to be driven. It has become so. Reference numeral 7 denotes an illumination lamp composed of a xenon lamp or the like, which is connected to a lamp driving circuit 8. Reference numeral 9 denotes a condensing lens which is disposed at a position where light emitted from the lamp 7 is condensed on one end surface of the light guide 4 via the color filter disk 5.

Reference numeral 10 denotes an image stationary switch, which is provided in the operation unit of the electronic endoscope 1 and is connected to an image stationary signal holding circuit 11 composed of a latch or the like. Reference numeral 12 denotes a driving circuit for the image pickup device 3 such as a CCD and a video circuit including a video amplifier and the like, to which the image pickup device 3 is connected. The output terminal of the video circuit 12 is connected to the A / D converter 13 and the A / D converter
An output terminal of the switch 13 is connected to a common terminal of a changeover switch 14 constituted by a semiconductor switch or the like. Each switching terminal of the changeover switch 14 is connected to an image memory (R1) 15, an image memory (G1) 16, and an image memory (B1) 17, each of which is composed of a semiconductor memory or the like. Image memory (R1) 15, Image memory (G1) 16, Image memory (B
1) Each output terminal of 17 further has an image memory (R2)
18, image memory (G2) 19, image memory (B2) 20, connected to image memory (R2) 18, image memory (G2) 1
9. The output of the image memory (B2) 20 is connected to be input to a D / A converter (R) 21, a D / A converter (G) 22, and a D / A converter (B) 23, respectively. ing.

The respective outputs of the D / A converter (R) 21, the D / A converter (G) 22, and the D / A converter (B) 23 are sent to the TV monitor 24 and a color shift detecting means is provided. It is supposed to be input to 25. The output end of the color misregistration detecting means 25 is connected to one input end of a comparator 26, and the other input end of the comparator 26 is connected to the output end of a threshold setting means 27 constituted by a variable resistor or the like. Have been. 28 is A
The output of the comparator 26 and the output of the image still signal holding circuit 11 are input to the ND circuit. The output of the AND circuit 28 is input to the image still control circuit 29. The output of the image still control circuit 29 is output to the image memory (R2) 18, image memory (G2) 19, and image memory (B2) 20. The signal is input to the stationary control terminal.

Next, the operation of the color misregistration prevention device in the endoscope image pickup device configured as described above will be described.
The white light emitted from the lamp 7 passes through a color filter disk 5 that is rotated and driven by a motor 6 to become R, G, and B color sequential light, and one of the light guides 4 of the electronic endoscope 1. Incident on the end face of. The color-sequential light incident on the end face of the light guide 4 is transmitted through the light guide 4, reaches the tip of the electronic endoscope 1, and the light guide 4
Is emitted from the other end surface of the. The emitted color sequential light illuminates a subject such as a stomach wall, and an image of the subject is formed on an image sensor 3 by an objective lens 2. The image sensor 3 is driven by the video circuit 12, and its output is converted into a video signal by the video circuit 12.

The output of the video circuit 12 is digitized by an A / D converter 13, and the digital image data is switched by a changeover switch 14 for each of R, G, and B component image data. 15, image memory (G1) 16 and image memory (B1) 17, respectively. The changeover switch 14 is adapted to be sequentially switched in synchronization with the rotation of the color filter disk 5 in accordance with the color of the color sequential light.

Next, the respective image data recorded in the image memory (R1) 15, the image memory (G1) 16 and the image memory (B1) 17 are converted into the image memory (R2) 18 and the image memory (G2).
19, transferred to the image memory (B2) 20 at high speed. This transfer operation is performed using the synchronization signal period of the television. Image memory (R2) 18, Image memory (G2) 19,
The image data transferred to the image memory (B2) 20 is read out in synchronism with the synchronizing signal of the television, and the D / A converter (R) 21, D / A converter (G) 22, D / A It is converted into an analog signal by the converter (B) 23 and displayed on the TV monitor 24. Normally, the above-mentioned transfer is performed for each frame, so that a moving image is observed on the TV monitor 24.

When observing an image while still, the operator presses the image still switch 10 to give a still instruction. When the image still switch 10 is pressed, an image still instruction signal is sent to the image still signal holding circuit 11. Even after the pressing operation of the image still switch 10 is released, the image still signal holding circuit 11 holds the still instruction signal.

On the other hand, the D / A converter (R) 21, D / A
Each output of the converter (G) 22 and the D / A converter (B) 23 is also input to the color misregistration detecting means 25,
In 25, the amount of color misregistration is detected by correlating images of each color for each frame. The color shift amount is compared with a value set in advance by the threshold setting means 27 by the comparator 26, and when the color shift amount becomes equal to or less than the set constant value, the comparator 26 is connected to one input terminal of the AND circuit 28. Output the true value. The output of the image still signal holding circuit 11 is input to the other input terminal of the AND circuit 28. The AND circuit 28 outputs an image only when both the outputs of the comparator 26 and the image still signal holding circuit 11 are true values. A control signal is sent to the stationary control circuit 29.

The image stillness control circuit 29 receives this control signal, and from the image memory (R1) 15, image memory (G1) 16, image memory (B1) 17, image memory (R2) 18, image memory at appropriate timing. (G2) 19, image memory (B
2) Stop the transfer of image data to 20. as a result,
Still images are stored in the image memory (R2) 18, the image memory (G2) 19, and the image memory (B2) 20.
On the V monitor 24, a still image is observed.

At this time, the still image to be observed is a still image in a state where the color shift is equal to or less than a certain value, and is an easy-to-view image with little color shift. To release the image stillness, the image still signal holding circuit 11 may be reset by a release switch (not shown), or the image still signal holding circuit 11 may be toggled by the image still switch 10.

The subject of the endoscope is mainly a living body, and as described above, the subject often moves due to the subject's heart, beating, or respiration, but both the beating and respiration have a certain period. At the timing, the subject is stationary or has very little movement. Therefore, as in the above embodiment, the color misregistration detecting means monitors the color misregistration amount, and detects a state in which the subject is stationary or the movement is extremely small and the color misregistration amount becomes a certain value or less. By making the image still, a still image from which the effect of color misregistration has been practically removed can be obtained.

FIG. 3 is a block diagram showing a specific configuration example of the color misregistration detecting means 25 in the embodiment shown in FIGS. FIG. 4 shows the relationship between the green (G) component and the blue (B) component of a normal endoscope image.
From this figure, the G component and B of each pixel constituting the endoscope image are shown.
It can be seen that the components vary in a limited range around the function of the straight line, and the correlation between B and G is high. The variation varies depending on the subject, but many pixels exist near the center straight line. Therefore, it can be considered that the ratio of the G component and the B component of many pixels of a normal endoscope image is almost constant.

Depending on the subject, as shown in FIG. 5, the G component and the B component may be distributed in a polygonal line shape. , G component and B component can be said to be almost constant.

In the configuration example shown in FIG. 3, color misregistration is accurately detected from the green and blue image signals based on the fact that the correlation between B and G specific to the endoscope image is high. Things. That is, the output of the D / A converter (G) 22 is input to one input terminal of the subtractor 30 and is also input to the integrator (1) 31, while the D / A converter (G) 22 B) The output of 23 is input to the other input terminal of the subtractor 30 via the variable gain amplifier 32 and to the integrator (2) 33. The outputs of the integrator (1) 31 and the integrator (2) 33 are input to a gain control circuit 34 for controlling the gain of the variable gain amplifier 32. The output terminal of the gain control circuit 34 Connected to control input.

The output terminal of the subtractor 30 is a window comparator
The window comparator 35 is connected to a window setting device 37 for setting a window. The output end of the window comparator 35 is an integrator (3)
The output of the integrator (3) 36 is input to the comparator 26 as the output of the color misregistration detecting means 25.

Next, the operation of the color misregistration detecting means configured as described above will be described. First, the output of the D / A converter (G) 22 is integrated by the integrator (1) 31 for one field or one frame period. On the other hand, the output of the D / A converter (B) 23 is amplified by the variable gain amplifier 32, and then the integrator (2)
At 33, integration is performed for one field or one frame period. The outputs of the integrator (1) 31 and the integrator (2) 33 are compared by a gain control circuit 34, and the output of the gain control circuit 34 is the output of each of the integrators (1) 31 and the integrator (2) 33. The gain of the variable gain amplifier 32 is controlled so that the outputs become equal.

As a result, in a normal endoscopic image, although the level of the G component is higher than that of the B component, the subtractor 30
The G component and the B component of the image signal input to are equal in integral value within a field or a frame period. Subtractor
Reference numeral 30 denotes an output of the D / A converter (G) 22 and a variable gain amplifier 32.
Is output, but if no color misregistration occurs, the pixel which makes the output of the subtractor 30 almost zero, that is, the value obtained by multiplying the G component and the B component by the gain of the variable gain amplifier 32 is equal. There are many pixels. Conversely, when color misregistration occurs, the number of pixels for which the output of the subtractor 30 is almost zero is smaller than that described above.

The window comparator 35 extracts only the pixel signal for which the output of the subtracter 30 is close to 0, and integrates the entire screen by the integrator (3) 36 to obtain the color shift amount of the entire screen. Therefore, the output of the integrator (3) 36 indicates the amount of color misregistration.
By inputting to 26, the control signal of the image stillness control circuit 29 can be obtained.

FIG. 6 is a block diagram showing another configuration example of the color misregistration detecting means. The output of the D / A converter (G) 22 is
The input is input to one input terminal of a divider 38. On the other hand, the output of the D / A converter (B) 23 outputs a value other than 0 when the input is 0. It is configured to be inputted to the other input terminal of the divider 38 via 39. The output end of the divider 38 is connected to a high-pass filter 40 that cuts off the DC component and passes only the AC component. The output of the high-pass filter 40 is input to an absolute value circuit 41 composed of a rectifier circuit or the like.
The output of 41 is input to an integrator 42 that performs an integration operation only for one field or one frame period. And this integrator 42
Is configured to be input to the comparator 26 as the output of the color misregistration detecting means 25.

Next, the operation of the color misregistration detecting means configured as described above will be described. The output of the D / A converter (B) 23 is replaced by the level replacement circuit 39 with a value near 1 only when its value is near 0. This is to prevent the denominator of the divider 38 from being near 0. The divider 38 calculates (G component) / (B component). As is clear from FIGS. 4 and 5 described above, the value of (G component) / (B component), that is, the slope of the function of the straight line in FIG.
As shown in FIG. 7, the value varies around a certain value, and the degree of the variation indicates a state of color misregistration.

FIG. 8 shows a temporal change in the output of the divider 38 within one field period. If there is no color shift, the variation is small.
Variation is increasing. The degree of this variation is extracted in the form of an AC component by the high-pass filter 40, and the amount is integrated by the absolute value circuit 41 and the integrator 42 over the entire screen. The output of the integrator 42 indicates the amount of color misregistration and is input to the comparator 26 to obtain an image still control signal.

FIGS. 9 and 10 are block configuration diagrams showing another embodiment of the present invention, and FIG. 9 shows an endoscope portion.
Reference numeral 10 indicates a color shift prevention device portion. The terminals c and d in FIG. 9 are connected to the terminals c'and d'in FIG. 10, respectively. In these figures, the same or equivalent components as those in the embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals. In FIGS. 9 and 10, reference numeral 30 is a general fiberscope, which is composed of an objective lens 2, a light guide 4, an image guide 31, an eyepiece lens 32, and the like. Reference numeral 33 denotes a color-sequential TV camera head detachably attached to the eyepiece of the fiberscope 30, which includes an imaging lens 34, an image pickup device 3, a dark box 35, and the like.
Is arranged at an image forming position on the end surface of the image guide 31 by the image forming lens 34. The image sensor 3 is a connection cord
It is connected to the video circuit 12 via 36.

As in the embodiment shown in FIGS. 1 and 2, the light from the lamp 7 driven by the lamp driving circuit 8 passes through the condenser lens 9 and the color filter disk 5 rotated by the motor 6. Light is condensed on one end face of the light guide 4 through the light guide 4. Reference numeral 10 denotes an image static switch composed of a foot switch, which is connected to the image static signal holding circuit 11 composed of a latch and the like and the timer 37.

The output of the video circuit 12 is supplied to an A / D converter 13
Are A / D converted by, and input to and recorded in the image memory (R1) 15, the image memory (G1) 16, and the image memory (B1) 17 through the changeover switch 14, respectively. The output terminals of the image memory (R1) 15, the image memory (G1) 16, and the image memory (B1) 17 are further connected to the image memory (R2) 18, the image memory (G2) 19, and the image memory (B2) 20, respectively. Connected and image memory (R2) 1
8, the output of the image memory (G2) 19 and the output of the image memory (B2) 20 are respectively a D / A converter (R) 21, a D / A converter (G) 22, and a D / A converter (B) 23. , And
The data is also input to the color misregistration detecting means 25 constituted by a digital correlator or the like.

The output of each of the D / A converters 21, 22, and 23 is a TV
The output of the color misregistration detecting means 25 is input to the monitor 24, and is input to one input terminal of the comparator 26, and the threshold setting means 27 is connected to the other input terminal of the comparator 26. The output of the comparator 26 and the output of the image still signal holding circuit 11 are input to the AND circuit 28, and the output of the AND circuit 28 and the output of the timer 37 are input to the OR circuit 38. The output of the OR circuit 38 is input to the image stillness control circuit 29, and the output terminal of the image stillness control circuit 29 has the image memory (R2) 18, the image memory (G2) 19, and the image memory (G2) 19, as in the above-described embodiment. It is connected to each image stillness control terminal of the image memory (B2) 20.

The operation of this embodiment is almost the same as that of the embodiment shown in FIGS. 1 and 2, but the different points are as follows. The subject image is formed on the image pickup device 3 via the objective lens 2, the image guide 31, the eyepiece lens 32, and the imaging lens 34, and the output signal is input to the video circuit 12. Since the image still switch 10 is constituted by a foot switch, an instruction of image still is issued by operating this switch with a foot. The color misregistration detection means 25 includes an image memory (R2) 18, an image memory (G2) 19, and an image memory (B
2) Since it is connected to 20, digital image data is directly input to this color shift detection means 25. Therefore, the color misregistration detecting means 25 digitally performs the same processing as that of the color misregistration detecting means shown in FIG. 3 or FIG.

The timer 37 is provided to cope with a case where the color shift of the captured image is not reduced and a signal is not output from the comparator 26 even if a fixed time has elapsed since the image stationary switch 10 was operated to give a still instruction. A signal is output after a predetermined time has passed from the timer 37, and the image still control circuit 29 is forcibly driven via the OR circuit 38 to freeze the image, so that a still image can be obtained. I have.

In the color misregistration detecting means shown in FIGS. 3 and 6, the integrator (1) 31, the integrator (2) 33, the integrator (3) 36, the integrator 42 and the like integrate the entire screen. However, in a normal electronic endoscope,
As indicated by oblique lines in FIG. 11, the endoscope image portion is a part. Therefore, when performing various integrations with each of the above integrators,
Pixels other than the endoscope image portion need to be excluded. For this purpose, a mask signal indicating the endoscope image section may be generated, and the function of the integrator may be controlled accordingly.

Further, the color misregistration detection may not be performed on the entire endoscope image, but may be performed only on the central portion of the image or only on a specific scanning line. In this case, an appropriate mask signal may be generated to detect a color shift only in a specific area.

In the color shift detecting means shown in FIGS. 3 and 6, the color shift is detected using the green (G) component and the blue (B) component, but the present invention is not limited to this. ,
The color misregistration may be detected using another color component image. Furthermore, once, the differentiation processing of the image is performed,
The color misregistration may be detected using two color component images in which the outline is emphasized or extracted. In short, the color shift of the color component image may be detected by some means.

In general, a video signal obtained from an electronic endoscope apparatus is gamma-corrected. However, in the present invention, it is processed through a circuit having an inverse gamma characteristic before being processed by a circuit having an inverse gamma characteristic before being processed. May be configured to perform. Further, the color misregistration prevention device according to the present invention may be incorporated in the electronic endoscope device, or may be configured separately from the electronic endoscope device and utilize a video signal obtained from the electronic endoscope device. Color misregistration may be detected and the image stationary operation of the electronic endoscope apparatus may be externally controlled.

[0042]

As described above with reference to the embodiments,
According to the present invention, the image output means outputs differently for a predetermined period.
Based on the captured image signal,
Detects the amount of color misregistration of the subject images that are captured more sequentially and compares them
Amount of color shift detected by the color shift detection means
Is less than the reference color shift amount,
The comparison with the output signal of the stillness indicating means for indicating the stillness of the image
Based on the output signal of the means,
The still image is obtained by stopping the moving image displayed on the display means.
Therefore, the still image with no color shift is
In order to obtain the image, a complicated operation of repeating the still instruction and releasing the still image is required until a still image with no color shift is obtained .
You can easily obtain a still image without color shift without
Wear.

The present invention also covers a plurality of different wavelength components.
Since it relates to a device that sequentially captures images , each wave is originally
It has a memory corresponding to the imaging signal of the long component image ,
Since it is possible to detect the <br/> color shift amount eject the image signal of each wavelength component from these memories do not require a separate extra memory. In addition, multiple different wavelength components
In an apparatus that sequentially captures images of objects , each wavelength component image
Image signals are combined into color, but the amount of color shift in the image signal of each wavelength component can be detected during the colorization period.
Since that is obtained advantages such as it is possible to detect the amount of color shift in near real-time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an electronic endoscope portion of an embodiment of a color shift prevention device according to the present invention.

2 is a block diagram showing a color shift prevention device portion of an embodiment of a color deviation preventing apparatus according to the present invention.

FIG. 3 is a block diagram showing one configuration example of a color misregistration detecting unit in FIG. 2;

FIG. 4 is a diagram showing a distribution state of a green component and a blue component of each pixel forming an endoscope image.

FIG. 5 is a diagram showing another distribution state of a green component and a blue component of each pixel forming an endoscope image.

FIG. 6 is a block diagram showing another configuration example of the color misregistration detecting means.

FIG. 7 shows the (green component) of each pixel constituting the endoscope image /
It is a conceptual diagram which shows the distribution state of the value of (blue component).

8 is a diagram showing a temporal change in the output of the divider in FIG. 6 within one field period.

FIG. 9 is a diagram showing a configuration of an endoscope portion according to another embodiment of the present invention.

FIG. 10 is a block diagram showing a color misregistration prevention device portion according to another embodiment of the present invention.

FIG. 11 is a diagram illustrating an endoscope image section in the electronic endoscope.

[Explanation of symbols]

 1 electronic endoscope 3 image sensor 4 light guide 30 fiberscope 31 image guide

Front Page Continuation (56) References JP 61-71790 (JP, A) JP 61-90635 (JP, A) JP 61-71791 (JP, A) JP 62-286011 (JP , A) JP-A-62-31266 (JP, A) JP-A-49-73921 (JP, A) JP-B 6-91880 (JP, B2)

Claims (1)

(57) [Claims] 1. An image pickup unit for sequentially picking up a subject image with a plurality of different wavelength components, an image memory unit for storing image pickup signals of different wavelength components sequentially output from the image pickup unit, and an output of the image memory unit. An image pickup is performed based on a monitor unit capable of displaying a moving image based on the signal, a stillness indicating unit instructing to stop the moving image displayed on the monitor unit, and an image pickup signal output from the image pickup unit for a predetermined period differently. Color shift detecting means for detecting the amount of color shift of the captured subject image, comparing means for determining that the color shift amount detected by the color shift detecting means is less than the reference color shift amount, and the stillness indicating means. Image stillness control means for controlling the image memory means on the basis of the output signal of the comparison means and the output signal of the comparison means to freeze the moving image displayed on the monitor means. A color misregistration prevention device.