JPS62156615A - Method for supplying illuminating light in electronic endoscope device - Google Patents

Abstract

PURPOSE:To obtain a vivid image in accordance with the use state and the observation position of an endoscope by changing phases of notched windows of two choppers provided between a light source and an optical system to control the supply time of an illuminating light pulse. CONSTITUTION:Halves of peripheral parts of choppers 27 and 28 driven by motors 25 and 26 are cut off to form windows 27a and 28a. The signal of a solid-state image pickup element 16 inputted from an endoscope 10 is projected on a monitor television; and choppers 27 and 28 are rotated once in every one frame scanning time, and phases of two windows of choppers are controlled and shifted from each other to control continuously the illuminating pulse supply time in accordance with the use mode and the observation position of the endo scope, thus projecting a vivid image with proper illumination.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for supplying illumination light in an electronic endoscope apparatus in which an endoscope and a monitor television are connected.

(Prior Art) To explain in detail about a known electronic endoscope device, an insertion section of an endoscope is inserted into a body cavity of a subject, and illumination light is emitted from an illumination window provided at the tip of the insertion section. COD, etc. in which the illumination light is reflected on the inner wall of the body cavity, and the reflected light enters through the observation window provided at the tip of the insertion section, and this light is placed inside the observation window. The charge is received by the light receiving part of the solid-state image sensor and charged and converted, and the resulting charge as an image signal of each pixel is transferred to the memory part of the solid-state image sensor at once (the transfer time is very short and it takes 0 to 1 (about m5ec)
. The image signals of each pixel stored in the storage section of the solid-state image sensor are sequentially sent to the video circuit. The video circuit converts this image signal into a TV video signal and sends it to the monitor TV.
This monitor TV displays images inside the body cavity.

For the above-mentioned monitor television, interlace scanning is performed in the same manner as in the general television signal transmission/reception system. That is,
In two field scans, odd and even, 1
Performing frame scanning. First, rough horizontal scanning is performed in odd-numbered field scans, and horizontal scanning is performed between the horizontal scanning lines in even-numbered field scans. Such interlaced scanning is effective as a means for handling fast-moving subjects. It is also effective as a means to prevent flickering caused by the short afterglow time of the phosphor in a cathode ray tube.

In the above-mentioned interlaced scanning, the image signal to be provided for each field scan is sent from the solid-state image sensor to the video circuit,
The video circuit sequentially outputs television video signals for odd-even field scanning based on the image signal.

By the way, when it is necessary to make a precise diagnosis, a frame memory can be used to store the television image (image signal) for one frame scan, and based on this television image signal, a still image can be displayed on a monitor TV for observation, or an optical disk can be used to record the image. recorded or photographed with a camera.

(Problems to be Solved by the Invention) However, the still image may not be clear and precise diagnosis may be difficult. The reasons for this are as follows.

Illumination light is continuously irradiated into the body cavity from the illumination window. Each pixel of the light-receiving section of the solid-state image sensor continuously receives reflected light over one field scanning time (1/60 second), and charges corresponding to the integral value of the amount of received light are stored. Therefore, when the object to be observed moves quickly, the amount of movement of the object during one field scanning time is stored as a blurred image, and the sharpness of the image itself in one field scanning is not sufficient. This principle is similar to the relationship between the opening time of a camera shank and the sharpness of a photographed image. That is, in a camera, image information is continuously stored on the film while the shunter is open, so if the above-mentioned time is long, the image of a fast-moving object becomes unclear.

Moreover, the still image displayed on the monitor TV is 2
Since the images of multiple field scans are superimposed, the amount of movement of the observation target in one frame scan time (1/30 second) ends up appearing as blur.

Therefore, the present inventor developed the following technology. That is,
A chopper is placed between the end of the illumination light transmission optical system of the endoscope and the light source, and this chopper is rotated by a motor, so that the window shaped like #i in the chopper crosses the luminous flux of the illumination light, thereby intermittent illumination light pulses are supplied to the illumination light transmission optical system. In addition, the time for storing image information in the solid-state image sensor (illumination time) is shortened to make the image clearer.

However, in the above-mentioned electronic endoscope apparatus, the supply time of the illumination light pulse is constant, which may be inconvenient. For example, when observing the upper gastrointestinal tract, the esophageal tube, which is affected by the beating of the heart, moves rapidly and the image is likely to blur, so it is better to supply the illumination light pulse for a shorter time. The inner wall of the esophageal tube is lighter in color than the pond area, and since it is observed closely, the illumination efficiency is high. A solid-state image sensor can store enough charge so that the image on a monitor TV does not become dark. On the other hand, the stomach has a large volume and tends to be observed from a distance, has poor illumination efficiency, and requires a large amount of illumination light, so the longer the supply time of the illumination light pulse, the better. Note that since the stomach moves slowly, image blur is relatively small even if the supply time of the illumination light pulse is lengthened.

As described above, it has been desired to adjust the supply time of illumination light pulses depending on the usage mode.

(Means for Solving the Problems) This invention was made to solve the above problems, and its gist is to convert the image signals obtained by the solid-state image pickup device of the endoscope into a video circuit. In an electronic endoscope device that converts the signal into a TV video signal and displays the video on a monitor TV based on the TV video signal, there is a connection between the end of the endoscope illumination light transmission optical system and the light source. Two choppers are arranged at The present invention provides a method for supplying illumination light in an electronic endoscope apparatus, characterized in that the supply time of the illumination light is adjusted.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4. 10 in Figure 1 is an endoscope l), this endoscope 1
0 does not have an eyepiece (- has a rig main body 11 and an insertion section 12 extending from the front end of this traction main body 11. The insertion section 12 is long and flexible. It has a curved portion 12a on its distal end side, and a hard distal end component 12b on its distal end side.An observation window 14 and an illumination window 15 are provided on the end surface of the distal end component 12b. A solid-state image sensor 16 consisting of a CCD is located inside the tip component 12I.
is arranged I), and the light receiving section 1 of this solid-state image sensor 16
6a and the observation window 14 are optically connected via a convex lens 17. A signal line 13 is connected to the solid-state image sensor 16 . The illumination window 15 is optically connected to one end 18a of an optical fiber bundle 18 (illumination light transmission optical system).

One end of a cable 19 is connected to the bottom surface of the operation main body 11, and the end of the cable 19 is connected to a processing box (
(not shown). The optical fiber bundle 18 and the signal line 13 are connected to the insertion section 12, the operating tree 11, and the cable 1.
9 and into the processing box.

An illumination light supply device 20 is built into the processing box. The illumination light supply device 20 has a light bulb 21 serving as a light source. The light bulb 21 is attached to the center of a shade 22 made of a concave mirror, and the light from the bulb 21 is reflected by the shade 22, condensed, and supplied to the end 18b of the optical fiber bundle 18.

The illumination light supply device 20 also includes two servo motors 25.
．． 26 and two disk-shaped first and second choppers 27 and 28 of the same diameter. Servo motor 25.26
The output shafts 25a and 26a are provided with choppers 27 and 26a, respectively.
The central part of 28 is fixed. Each chopper 27.28
By cutting out the periphery of each window 27 by 180°,
a, 28a are formed, and the peripheral portions of the pond having the same diameter as these windows 27a, 28a serve as shielding portions 27b, 28b.

I
Magnets 33 and 34 are attached to positions opposite 80'. In addition, position sensors 35, 36 consisting of proximity switches are arranged near the choppers 27, 28, and magnets 33, 34 on the choppers 27, 28
The position of each is detected.

Inside the processing box, as shown in Figure 2, there are video circuits,
It has built-in electrical circuits for <0 and its pond.

The video circuit 40 connects the solid-state image sensor 1 via the signal line 13.
6. A frame memory 42 is connected to this video circuit 40 via a processing circuit 41, and a monitor television 43 is also connected.
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L (), CalTll1il! ? a ,i I
.

Frame memory 42. Since the monitor television 43 is well known, detailed description thereof will be omitted.

The video circuit 40 also includes an odd field integration circuit 47 and an even field integration circuit 4 via a selector 45.
8 are connected. The odd field integration circuit 47 includes a humpator 49 . A chopper control circuit 53 is connected via a selector 51. The even field integration circuit 48 also includes a humpator 50. A chopper control circuit 54 is connected via a selector 52. Each chopper control circuit 53, 54 controls the driving of the motors 25, 26 to control the rotation of the choppers 27, 28.

Further, a synchronization circuit 60 is connected to the video circuit 40. The synchronization circuit 60 includes a horizontal synchronization signal separation circuit 61, a vertical synchronization signal 1 separation circuit 62, and a frame synchronization signal generation circuit 63.

A coincidence switching circuit 64 is connected to the synchronization circuit 60, and is configured to switch the selector 45.

The synchronization circuit 60 includes two position error signal generation circuits 55.
56 are connected. These position error signal generation circuits 5
5.56 are connected to the aforementioned selectors 51.52, respectively. In addition, 57.58 in the figure is the selector 51
．． This is a comparator for switching and operating 52.

The operation of the electronic endoscope device having the above configuration will be explained. The operator inserts the insertion section 12 into the main cavity of the subject while holding the retractable wood 11 of the endoscope 10 with his/her hand. For example, it is inserted through the mouth into the esophagus or stomach. The light from the light bulb 21 passes through the optical fiber bundle 18 and is irradiated into the body cavity from the illumination window 15. The reflected light from the inner wall of the body cavity passes through the observation window 14 and the convex lens 17 and reaches the solid-state image sensor 16 . As a result, an image of the inner wall of the body cavity is formed on the light receiving section 16a of the solid-state image sensor 16.

The light receiving section 16a of the solid-state image sensor 16 charges and converts the projected image and stores the image signal as a charge.

In the solid-state image sensor 16, charges for one field scan are transferred from the light receiving section 16a to the storage section 16b in a short time based on the transfer timing signal from the video circuit 40. The video circuit (0 receives the image signal Sg from the storage section 16a of the solid-state image sensor 16, converts it into an NTSC television video signal SL, and sends it to the monitor television 43. As a result, the monitor television 43 uses the interlaced scanning method. An image of the inner wall of the body cavity is displayed.

The operator operates the endoscope 10 while watching the monitor television 13 to observe the inside of the body cavity. When detailed inspection is required,
One frame scanning portion of the television video signal St is stored in a frame memory 42 according to a command from a processing circuit 41, and is repeatedly read out by the processing circuit 41 and sent to a monitor television 43, thereby displaying a still image on the monitor television 43.

Next, the supply of illumination light will be explained in detail. Motor 25.2
6 rotates the choppers 27 and 23, respectively. The choppers 27 and 28 rotate once per frame scanning time. When either the shielding part 27b of the first chopper 27 or the shielding part 28b of the second chopper 28 is slow in transmitting the luminous flux A of the illumination light, the illumination light is not supplied into the body cavity from the illumination window 15, and both choppers 27 .28 window 27a
, 28a are at the position of the light beam A, the illumination light is supplied. As a result, illumination light pulses are supplied intermittently.

The supply time of the illumination light pulses can be adjusted by controlling the rotation of the chopper 27°28. Chopper 27.
The method of controlling the rotation of the motor 25 is different between the transition period immediately after the motor 25 and 26 start driving and the subsequent stable period.

(over) irregular control is synchronous control described below.

To be more specific, in the synchronization circuit 60, the television video signal St from the video circuit 40h, etc. is transmitted to the horizontal synchronization signal separation circuit 61,
The signal is sent to the vertical synchronization signal separation circuit 62.

In the horizontal synchronization signal separation circuit 61, the television video signal S
Separate horizontal synchronization signal SI+ and equalization signal sp from L,
These signals sh and sρ are sent to a frame synchronization signal generation circuit 63.
Output to. Further, the vertical synchronization signal separation circuit 62 separates the vertical synchronization signal Sv from the television video signal St and outputs it to the frame synchronization signal generation circuit 63. In this frame synchronization signal generation circuit 63, the horizontal synchronization signal separation circuit 61
Based on the time difference between the last horizontal synchronizing signal sh and the first geometric ratio signal sp received from When one of the two vertical synchronization signals Sv is received, for example, the vertical synchronization signal Sv for an odd-numbered field scan (that is, once for each frame scan), frame synchronization is performed. The signal Sf is sent to phase difference deviation signal generation circuits 55 and 56.

On the other hand, the position sensors 35 and 36 detect the magnet 33.
34 and sends the detected position signal 5t)O to the phase difference deviation signal generation circuit 5'5.56.

The phase difference deviation signal generation circuits 55 and 56 compare the frame synchronization signal SF from the frame synchronization signal generation circuit 63 and the detected position signal Spo from the position sensor 35 and 36 to detect the phase difference between them. Compared to the set phase difference,
A phase difference deviation signal Sre is output. This phase difference deviation signal Sre is sent to chopper control circuits 53 and 54 via selectors 51 and 52.

In the chopper control circuit 53.54, the position sensor 35.3
From the frequency of the detected position signal Spo from 6, the chopper 27
．． The rotational speed of the chopper 28 is detected, and the power supplied to the motors 25.degree. 26 is increased or decreased based on the detected rotational speed and the phase difference, thereby controlling the rotation of the choppers 27.degree. With this control, the point in time at which the central portions of the windows 27α and 23a pass the light beam A is moved one inch closer to the point in time at which the image signal used for odd field scanning is transferred.

When the level of the phase difference deviation signal Sre becomes lower than the set phase difference deviation level Lre of the comparators 57 and 58, in other words, the window 27a
The selectors 51 and 52 are switched when the time point at which the light flux of +28a passes and the time point at which the image signal is transferred are almost equal.

By switching the selectors 51 and 52, the control shifts to stable period control, that is, control based on brightness.

To be more specific, the odd-even switching circuit 64 receives only the vertical synchronizing signal Sv from the vertical synchronizing signal separation circuit 62;
This vertical synchronization signal Sν and the frame synchronization signal generation circuit 63
The selector 15 is switched by determining whether or not the frame synchronization signal Sf. Every time this selector 45 switches, the odd field integrator 1
7 integrates the odd field scanning television video signal SL to detect its brightness, and an even field integrating circuit 48 integrates the even field scanning television video signal Sj to detect its brightness. Detection brightness signal S from odd field integration circuit 471. is sent to the comparator 9↓9, which compares it with the set brightness level Lb+ and outputs a brightness difference signal 5ane. The chopper control circuit 53 controls the rotation of the first chopper 27 based on the brightness difference signal 5ane and the detected rotational speed, and adjusts the phase of the window 27a of the first chopper 27. That is, by adjusting the time from the time when the window 27a reaches the luminous flux A to the time when the image signal of the odd field is transferred (FIG. 4), the brightness signal S of the image of the odd field is adjusted.
+n, is made to match the brightness level Ln+.

The above time or the illumination light pulse supply time (the first half of the total illumination light pulse supply time from the image signal transfer time point) when storing the image signal for odd field scanning in the solid-state image sensor 16 Equivalent to.

On the other hand, the comparator 50 receives random brightness signals S m l l S Ifl 2 from the integrating circuits 47 and 48, respectively.
is sent to the comparator 50, and the brightness difference signal Sme' is sent to the chopper control circuit 54 via the selector 52.
send to In the control circuit 54, this brightness difference signal S++l
e' and the detected rotational speed, the second chopper 28
and adjusts the phase of the window 28a of the second chopper 28. That is, from the time of image signal transfer, the window 28
Adjusting the time X' until the point when a deviates from the luminous flux A,
The levels of the brightness signal S Ill 1 of the video of the odd field and the brightness signal S+02 of the video of the even field are made to match. As a result, the above-mentioned time period and time X' become equal. The aforementioned time ).

As mentioned above, the brightness difference signal Sm from the comparator 49
The phase control of the first chopper 27 based on e is performed to adjust the supply time of the illumination light pulse so that the brightness is constant. Further, the phase control of the second chopper 28 based on the brightness difference signal Sme' from the comparator 50
Following the phase control of the chopper 27, this is performed in order to accurately distribute the supply time of the illumination light pulses in half with respect to the image signal transfer time point.

As described above, the supply time of the illumination light pulse is divided in half at the time of image signal transfer.

If illumination light pulses are supplied at such timing,
In the light-receiving section 16a of the solid-state image sensor 16, when no illumination light pulse is supplied during each field scanning period, the field becomes a dark field. This means that a charge corresponding to the amount of light received during that period is stored. Furthermore, since the accumulation period of the image signal to be subjected to odd field scanning and the accumulation period of the solid image signal to be subjected to the subsequent even field scanning are continuous, one frame scanning displayed on the monitor television 43 The minute still image is constructed by superimposing two images (field scan images) accumulated during each half of the illumination light pulse supply time.

Therefore, the above-mentioned still image is based on the image information accumulated during the supply time of the illumination light pulse, and is less blurred than the conventional image based on the image information accumulated during one frame scanning period. can be made clearer.

In addition, since the choppers 27 and 28 are controlled so that the brightness of the scanned image is equal to the odd-even field, there are manufacturing errors in each component, dimensional errors due to temperature changes, and changes in characteristics. However, the illumination light pulse can always be divided into halves exactly at the above-mentioned transfer point, and the image displayed on the monitor television 43 has no flicker, has good image quality, and can accurately reproduce colors.

The phase control of the choppers 27 and 28 described above is performed on the actual endoscope 1.
This will be explained in the usage mode of 0.

For example, when observing the esophagus using the endoscope 10, the wall surface of the esophagus is brightly colored, and the illumination efficiency is high because the esophagus is observed from a close distance. That is, the proportion of the amount of light reflected from the illumination light emitted from the illumination window 15 and entering through the observation window 14 is high. In this case, in response to high illumination efficiency, the brightness of the image is adjusted to a constant value by shortening the supply time of illumination light pulses and reducing the amount of illumination light provided for one field scan). Since the esophagus moves rapidly under the influence of the heartbeat, it is preferable to shorten the supply time of the illumination light pulse, and the above adjustment satisfies this requirement.

Furthermore, for example, when the endoscope 10 observes the stomach, the stomach has a large volume and tends to be observed from a distance, resulting in poor illumination efficiency. Therefore, the proportion of the amount of light entering through the observation window 14 is low. In this case, in response to low illumination efficiency, the brightness of the image is adjusted to a constant level by lengthening the supply time of illumination light pulses and increasing the amount of illumination light to be provided for one field scan. In the stomach, the movement is relatively slow, so there is no problem even if the supply time of the illumination light pulse is slightly longer.As mentioned above, the supply time of the illumination light pulse can be adjusted depending on each usage mode. It is possible to reliably prevent image blurring and to maintain appropriate brightness of the image. Moreover, since the supply time of illumination light pulses can be adjusted steplessly,
Adjustments can be made reliably to suit the mode of use.

In addition, at the initial stage of driving the motors 25 and 26, the time for the chopper 27 and 28 power bows to rotate is significantly different from the time for scanning one frame, and the motors 25 and 2 are driven based on the brightness.
6 is difficult to control.

For this reason, first, the rough chopper 27 is
．． 28 are controlled.

The present invention is not limited to the above embodiments, and various embodiments are possible. For example, as shown in FIG. 5, two choppers 27.degree. 28 may be rotated by driving one motor 25. In this example, the center portion of the first chopper 27 is fixed to the output shaft 25a of the motor 25. A shaft 70 is fixed to the center of the first chopper 27 on the opposite side of the output shaft 25a, and a pin 71 is protruded from the shaft 70. A cam groove 72 is provided in the center of the second chopper 28.
The shaft 70 is inserted into the sleeve 73, and the cam groove 7 is inserted into the sleeve 73.
A pin 71 is inserted into 2.

A compressed fill spring 74 is housed between the second chopper 28 and the end surface of the shaft 70. A bearing 75 is provided on the side surface of the central portion of the second chopper 28, and one end of a shaft 76 is rotatably inserted into the bearing 75. A rack 77 consisting of a plurality of rows of annular projections is formed on the outer periphery of the end of the shaft 76, and a pinion 78 is engaged with the rack 77. This pinion 78 is a motor for adjusting the pond phase (
(not shown).

In the above configuration, when the motor 25 rotates, the first chopper 27 rotates, and due to the engagement between the pin 71 and the cam groove 72 (1), the second chopper 28 rotates at the same speed about the shaft 76.

Then, when the pinion 78 is rotated by a motor (not shown) in response to the brightness signal of the image, the shaft 76 moves in the axial direction due to the meshing action between the pinion 73 and the rack 77, and the second chopper 28 becomes the first chopper. Approach or move away from 27. At this time, due to the cam action of the pin 71 and the cam groove 72, the second chopper 28 or the first chopper 27 rotates relative to each other, and as a result, the phases of the windows of both choppers 27 and 28 change. However, the overlapping portion of the side windows, that is, the actual opening angle of the windows changes. This adjusts the supply time of the illumination light pulse.

Furthermore, in the present invention, in addition to the effects of the above embodiments, two
By moving the two choppers in a direction intersecting the light beam, the rotation locus of the chopper may be removed from the light beam by 1), so that illumination light can be continuously supplied.

Further, the position sensor is not limited to a proximity switch, but may be a photoelectric switch or the like.

In the above two embodiments, the brightness of the video is detected and the chopper is automatically moved based on this brightness signal, but the chopper may be stopped by manually operating a switch.

The two choppers do not have to have the same diameter. Also, the angle range of each chopper may be wider than 130'.

The chopper windows may have a plurality of windows arranged at equal angular intervals in parts of the same diameter. In this case, when the chopper rotates once, a certain number of frames are scanned.

The chopper may be linearly reciprocated by a plate cam or the like rotated by a motor to cross the light beam.

The light incident from the observation window may be received by one end face of the optical viR bundle, the optical fiber bundle may be guided outside the operation main body in the same way as the optical fiber bundle for illumination, and the solid-state image sensor may be disposed on the end face of the optical fiber bundle. .

Still images from a monitor TV may be recorded on an optical disc or photographed using a hooded camera.

Furthermore, without using a frame memory, 17 frame scans of the moving image displayed on the monitor television may be photographed using an external camera with a hood.

The present invention can also be applied when using an electronic endoscope device for industrial inspection.

(Effects of the Invention) As explained above, in this invention, by moving the chopper with a motor to cross the beam of illumination light, it is possible to supply illumination light pulses for each frame scan, and to Even if the object is to be photographed intensely, the image for one frame scan can be made clear. In addition, by changing the phase of the two choppers (1), the supply time of illumination light can be adjusted steplessly, and appropriate illumination can be performed depending on the mode of use.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention,
Figure 1 is a perspective view showing an endoscope and illumination light supply device in an electronic endoscope system, Figure 2 is an electric circuit diagram of the electronic endoscope system, and Figure 3 is the positional relationship between the chopper and the luminous flux of illumination light. FIG. 1 is a front view showing a time chart. Also, the fifth
The figure is a side view of an illumination light supply device showing an embodiment of the pond according to the present invention. DESCRIPTION OF SYMBOLS 10... Endoscope, 11... Working body, 12... Insertion part, 16... Solid-state image sensor, 16a... Light receiving part,
16b... Storage unit, 18... Optical fiber bundle (illumination light transmission optical system), 20... Illumination light supply device, 21... Light bulb (light source), 25° 26... Motor, 26. 27...
・Chopper, 27a, 28a...window, 27b, 23b
...shielding part, 40... video circuit, 43... monitor television,

Claims (2)

[Claims] (1) An electronic endoscope device that converts the image signal obtained by the endoscope's solid-state image sensor into a TV video signal using a video circuit, and displays the video on a monitor TV based on this TV video signal. In this method, two choppers are arranged between the end of the illumination light transmission optical system of the endoscope and the light source, and the choppers are moved by a motor to cross the illumination light beam, thereby intermittently transmitting the illumination light. A method for supplying illumination light in an electronic endoscope apparatus, characterized in that the supply time of illumination light pulses is adjusted by supplying pulses and changing the phases of two choppers. (2) The chopper is disc-shaped and has a window, and by rotating this chopper with a motor so that the window crosses the luminous flux of the illumination light, pulses of illumination light are intermittently supplied, By changing the phase of the chopper windows,
2. A method for supplying illumination light in an electronic endoscope apparatus according to claim 1, wherein the supply time of the illumination light pulse is adjusted.