JP2001154085A - Endoscopic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscopic device capable of presenting a natural easy-to-view image to an observer by eliminating an unnecessary focusing operation as much as possible. SOLUTION: A change of light quantity is detected by a light quantity change detection circuit 38, and when the change exceeds a prescribed value, an automatic focus detecting operation is started by a lens control circuit 39 of a processor 30. Then it is judged whether an object comes nearer or goes far away, based on the opening/closing direction of the aperture 13 of a light source device 10, and a liquid crystal lens 23 is moved according to the opening/closing direction, and when the maximum focusing evaluation value is obtained, the automatic focus detecting operation is finished. Also after the automatic focus detecting operation is finished, the device is set in a standby state until the light quantity changes again. The liquid crystal lens 23 is driven, in such a way according to the quantitative change of the light for illuminating the object and the focused state of the object, then, the automatic focusing operation is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an endoscope apparatus having a so-called autofocus function.

[0002]

2. Description of the Related Art In recent years, endoscopes capable of observing diseased parts or the like by inserting an elongated insertion part into a body cavity and performing treatment on these diseased parts as necessary have been widely used. Generally, an endoscope apparatus includes an endoscope described above, a light source apparatus that supplies illumination light to the endoscope, and an image pickup device such as a charge-coupled device (CCD) provided at the end of the endoscope. And a monitor for displaying the video signal of the video processor.

[0003] Among such endoscope devices, there is a so-called autofocus endoscope having a focal length variable mechanism capable of varying a focal length according to a distance from a subject. This autofocus endoscope has a drive unit for driving a movable part of a focal length variable mechanism, and drives and controls the drive unit using a drive control signal obtained from any focus control unit, so that the focus on the subject can be improved. Automatically adjust the distance. Regarding the control of the variable focal length mechanism, for example, Japanese Unexamined Patent Publication No. 4-13112 discloses a method of detecting a light amount from a signal from a focus detection unit and an opening state of an aperture of a light source device that supplies illumination light to an endoscope. There has been proposed a technique for controlling a variable focal length mechanism based on a signal from a light amount detection unit. Specifically, when a focus shift is detected based on a signal from the focus detection unit, it is determined whether the aperture is stopped down based on a signal from the light amount detection unit, and the focal length variable mechanism is controlled based on the result.

[0004]

By the way, as in the above prior art, if the autofocus is executed while observing the light amount and the focus shift, the endoscope image has a movement.
Focusing will start even for a relatively small movement between the endoscope and the subject, and the image to be processed may be rather unnatural and difficult to see.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an endoscope apparatus of an image which is natural and easy to see for an observer by eliminating unnecessary focusing as much as possible. I have.

[0006]

In order to achieve the above object, an endoscope apparatus according to the first aspect of the present invention provides an endoscope with an adjustable focus for imaging a subject and illumination light to the endoscope. Light source means, image signal processing means for processing an image signal from the endoscope into a video signal, aperture control means for controlling the amount of illumination light from the light source means, and light amount change by the aperture control means. A light amount change detecting means for detecting, a focus evaluation value calculating means for obtaining a focus evaluation value from a signal of the video signal processing means, and a light amount change from the light amount change detecting means based on the focus evaluation value when a light amount change exceeds a set range. And a focus adjustment control means for controlling the focus adjustment of the endoscope.

The endoscope apparatus according to the first aspect of the present invention supplies illumination light from the light source means to the endoscope to capture an image of a subject, and the image signal from the endoscope is converted into a video signal by the video signal processing means. Is processed. When observing the subject in this way, the aperture control unit controls the light amount of the illumination light from the light source unit, the light amount change detection unit detects the light amount change by the stop control unit, and the focus evaluation value calculation unit A focus evaluation value is obtained from a signal of the video signal processing means. Then, the focus adjustment control means controls the focus adjustment of the endoscope based on the focus evaluation value when the light amount change from the light amount change detection means exceeds the set range.

According to a second aspect of the present invention, in the endoscope apparatus according to the first aspect, motion detection is performed to detect a motion of the endoscope and the subject that is greater than a relative setting. Having a means, when detecting a movement of the relative setting or more, characterized in that the control of the focus adjustment control means is held in a state before the movement of the relative setting or more, When a motion exceeding a relative setting is detected by the motion detecting means, unnecessary focusing is eliminated as much as possible.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention.
FIG. 1 is a block diagram of an endoscope apparatus, FIG. 2 is an explanatory diagram of a configuration of a focus evaluation value calculation circuit, and FIG. 3 is a flowchart of focus adjustment control.

In FIG. 1, reference numeral 1 denotes an endoscope device. The endoscope device 1 includes a light source device 10 as a light source unit for supplying illumination light, and a subject (not shown) inserted into a body cavity. An endoscope 20 that captures images, a processor 30 as a video signal processing unit that performs signal processing of image signals from the endoscope 20, and the like, and a monitor 50 that displays images are mainly configured. .

The light source device 10 includes a lamp 11 for emitting illumination light, a rotary filter plate 12 provided on the illumination optical path of the lamp 11 to limit a transmission wavelength, and a diaphragm for varying the amount of illumination light of the lamp 11. 13 and an aperture control circuit 14 therein.

The endoscope 20 includes the light source device 1.
A light guide 21 for guiding illumination light from 0 to irradiate a subject, a CCD 22 for capturing light from the subject, and a liquid crystal lens 23 whose focal position can be changed by an applied voltage.
And

Further, the processor 30 has a CC inside.
D drive circuit 31, pre-processing circuit 32, A / D conversion circuit 33, signal processing circuit 34, D / A conversion circuit 35, photometry circuit 36, focus evaluation value calculation circuit 37, light quantity change detection circuit 38, lens control circuit 39 And liquid crystal lens drive circuit 40
Is configured.

The light radiated from the lamp 11 of the light source device 10 passes through the rotary filter plate 12 and the stop 13 and enters the light guide 21 of the endoscope 20.
At this time, the rotary filter plate 12 is driven to rotate at a predetermined speed by a motor (not shown), and an R filter, a G filter, and a B filter (each not shown) are sequentially put on the optical path, and the red, green, and blue filters are turned on. Light is sequentially transmitted. Further, in accordance with the output of the photometric circuit 36 of the processor 30, the aperture control circuit 14 of the light source device 10 controls the opening and closing of the aperture 13 so that the brightness of the image on the monitor screen is constant. Is automatically adjusted so that

Thus, the light guide 21 of the endoscope 20
Incident on the subject is irradiated from the distal end of the endoscope to a subject such as a digestive tract in a body cavity. Then, the light scattered and reflected by the subject passes through the liquid crystal lens 23 at the end of the endoscope and passes through the CCD 2.
2 is imaged.

The CCD 22 is driven by a CCD drive circuit 31 of the processor 30 and is illuminated with light transmitted through the respective filters of the rotary filter plate 12 of the light source device 10, such as an R filter, a G filter, and a B filter. The imaging signals of the CCD 22 at the time of the occurrence are sequentially output to the processor 30.

The CC input to the processor 30
The imaging signal of D22 is first input to a pre-processing circuit 32, and an image signal is extracted by a process such as CDS (correlated double sampling), and is converted from an analog signal to a digital signal by an A / D conversion circuit 33. You.

The digital signal converted by the A / D conversion circuit 33 is subjected to a white balance,
After signal processing such as RGB synchronization and gamma correction is performed, the signal is converted into an analog video signal by a D / A converter 35,
The image is output to the monitor 50 and an endoscope image is projected.

The output from the A / D conversion circuit 33 is input to a photometric circuit 36, which outputs a signal corresponding to the brightness of the subject image, and controls the aperture of the light source device 10. It is sent to the circuit 14. The aperture control circuit 14 controls the aperture of the aperture according to the signal sent from the photometric circuit 36, and controls the amount of emitted light so that the brightness of the screen is constant.

Further, the G (green) image of the digital video signal output from the A / D conversion circuit 33 is also input to a focus evaluation value calculation circuit 37. The focus evaluation value calculation circuit 37 serves as focus evaluation value calculation means, and mainly includes an HPF 37a, an absolute value circuit 37b, a mask circuit 37c, an addition circuit 37d, a memory 37e, and a comparison circuit 37f, as shown in FIG. It is configured.

The signal input to the focus evaluation value calculation circuit 37 is such that the high frequency component contained in the signal is
The video signal is extracted by 7a, further converted to a positive number by an absolute value circuit 37b, and subjected to a masking process of a central portion of the video signal by a mask circuit 37c. The masked video signal is sent to an addition circuit 37d, where the high-frequency components for one field of the masked portion are added, and the addition result is stored in a memory 37e and simultaneously sent to a comparison circuit 37f. Sent. The comparison circuit 27 compares the obtained focus evaluation value with that obtained one field before, and outputs the comparison result to the lens control circuit 39.

On the other hand, when the endoscope 20 approaches the subject, the aperture 13 of the light source device 10 moves in a closing direction,
When the endoscope 20 moves away, the diaphragm 13 moves in the opening direction.

The aperture control circuit 14 of the light source device 10 sends a signal indicating the position of the aperture 13 to the light amount change detection circuit 38 of the processor 30 and the light amount change detection circuit 3
In step 8, the output of the aperture control circuit 14 is compared in synchronization with the vertical synchronizing signal. That is,
The light quantity change detection circuit 38 is provided as light quantity change detection means.

The lens control circuit 39 serves as focus adjustment control means, and includes the focus evaluation value calculation circuit 37,
From the output of the light amount change detection circuit 38, focus adjustment control processing is performed according to the flowchart of FIG. The adjustment of the focal position by the endoscope apparatus 1 according to the first embodiment is performed as follows.
The adjustment is made in five steps from near point to far point.

When the focus adjustment control program shown in FIG. 3 starts, first, step (hereinafter abbreviated as “S”) 1
At 01, a focus evaluation value is calculated for each step from the near point to the far point.

Then, the process proceeds to S102, in which the liquid crystal lens driving circuit 40 is driven to move the liquid crystal lens 23 so as to be at the position of the focus evaluation value which is the largest among the focus evaluation values calculated in S101. .

Then, the process proceeds to S103, where it is determined from the comparison result from the light amount change detection circuit 38 whether the diaphragm 13 has moved by a predetermined value or more. If it has moved, the process proceeds to S104, and if it has not moved by more than the preset value, S10
3 is repeated. In other words, it waits for a change in the amount of light.

If it is determined in step S103 that the aperture 13 has moved by a predetermined value or more and the process proceeds to step S104, it is determined whether or not the aperture 13 has moved in the closing direction, and the aperture 13 has moved in the closing direction. In the case where
When the process of S108 is performed and the aperture 13 moves in the opening direction, the processes of S109 to S112 described later are performed.

If it is determined in step S104 that the diaphragm 13 has moved in the closing direction and the process proceeds to step S105, it is determined whether the position (stage) of the liquid crystal lens 23 is the nearest point. Returning to S103 with the position,
If it is not the nearest point, the process proceeds to S106.

In step S106, the position (step) of the liquid crystal lens 23 is moved one step toward the near point, and thereafter, in step S107.
Then, it is determined whether or not the focus evaluation value has increased.

If the result of the determination in S107 is that the focus evaluation value has increased, the flow returns to S105, and if the focus evaluation value has decreased, the flow proceeds to S108 to proceed to step S108.
Is moved to the far point by one step, and the above S
The processing from step 103 is repeated. That is, the position of the liquid crystal lens 23 is moved to a position where the focus evaluation value becomes the highest.

On the other hand, as a result of the determination in S104, the diaphragm 1
If it is determined that the liquid crystal lens 3 has moved in the opening direction and the process proceeds to S109, it is determined whether or not the position (step) of the liquid crystal lens 23 is the farthest point. Returning to S103, if it is not the farthest point, the process proceeds to S110.

In step S110, the position (step) of the liquid crystal lens 23 is moved one step toward the far point, and thereafter, in step S111.
Then, it is determined whether or not the focus evaluation value has increased.

If the result of the determination in S111 is that the focus evaluation value has increased, the flow returns to S109, and if the focus evaluation value has decreased, the flow proceeds to S112 to proceed to step S112.
Is moved to the near point side by one step, and the above S
The processing from step 103 is repeated. Thus, the above S105
The position of the liquid crystal lens 23 is moved to the position where the focus evaluation value becomes highest in the same manner as in S108.

As described above, according to the first embodiment,
The lens control circuit 39 of the processor 30 detects a change in light amount by the light amount change detection circuit 38, and starts an automatic focus detection operation when the change amount exceeds a preset value. Then, it is determined whether the subject has approached or moved away from the opening / closing direction of the aperture 13 of the light source device 10, the liquid crystal lens 23 is moved according to the direction, and the automatic focus detection operation is ended when the focus evaluation value becomes maximum. . Also,
After the end of the automatic focus detection operation, the process waits for a change in light amount again. In this way, the liquid crystal lens 23 can be driven in accordance with the change in the amount of illumination light to the subject and the in-focus state of the subject, and the automatic focusing operation can be performed.

As a result, unnecessary focusing on fine small movements is eliminated as much as possible, and a natural and easy-to-view image is provided to the observer.

In the first embodiment, the focus evaluation value is calculated by adding one field period. However, the present invention is not limited to this. The focus evaluation value may be calculated for a plurality of field periods. Further, the focus evaluation value is calculated only for the G (green) image, but the focus evaluation value is not limited to the G image,
(Luminance) images, R (red), B (blue) images, and the like. Further, in the first embodiment, the description has been made with reference to the application to an optical zooming device. However, it is needless to say that the present invention can be applied to an electronic zooming device.

FIGS. 4 to 6 show a second embodiment of the present invention. FIG. 4 is a block diagram of an endoscope apparatus, FIG. 5 is an explanatory diagram of a configuration of a control selection circuit, and FIG. 7 is a flowchart of focus adjustment control according to the circuit. In the second embodiment, when there is a color shift, control is performed so that the lens is not forcibly driven with respect to the subject, and is configured in the same manner as the first embodiment. The same reference numerals are given to the parts and the description is omitted.

Therefore, as shown in FIG. 4, the processor 61 of the endoscope apparatus 60 according to the second embodiment includes a color shift detection circuit 62 in addition to the processor of the endoscope apparatus according to the first embodiment. And a control selection circuit 63.

As shown in FIG. 5, the control selection circuit 63 stores a lens position before a color shift occurs when a signal indicating that there is a color shift is output from the color shift detection circuit 62. The circuit 63a is provided with a selector 63b for switching lens driving in accordance with a signal output from the color misregistration detection circuit 62.

The control selection circuit 63 receives signals from the lens control circuit 39 and the color shift detection circuit 62, and controls the liquid crystal lens drive circuit 40. FIG. 6 shows the auto focus control related to the control selection circuit 63.
This will be described with reference to FIG.

The plane-sequential electronic endoscope picks up R, G, and B primary color signals one by one every 1/60 second. Therefore, when an image of a moving object is captured, R, R
Since the G and B primary color signals cannot be captured, the colors of the object are separated. The state in which the colors are separated is called color shift.

The color shift detecting circuit 62 detects the color shift, has a delay memory (not shown), and compares the delayed color component with the non-delayed color component to detect the degree of the color shift. It is.

Upon receiving the signal from the color misregistration detection circuit 62, the control selection circuit 63 performs the processing shown in FIG. When no color shift is detected, the control selection circuit 63
Selector 63b is on the SEL = 0 side, and the same lens control as in the first embodiment is performed.

When the flowchart shown in FIG. 6 is started, when the power is turned on, flagA = 0 is set in S201, and a signal from the color misregistration detection circuit 62 is waited.

Next, in S202, it is determined whether or not a color shift is detected by the color shift detection circuit 62. If there is a color shift, the process proceeds to S203 to S206 described below, and there is no color shift. In this case, the process proceeds to S207 to S209 described below.

If it is determined in step S202 that there is color misregistration, and the flow advances to step S203, it is determined whether or not flagA = 0. If flagA = 0, the flow advances to step S204, and the lens position storage circuit 63a stores 1 in flagA. Is performed, and then the process proceeds to S205, in which the process proceeds to a process of reading the lens position before color shift.

If flagA ≠ 0 in step S203, the process directly jumps to step S205.
Move on to the process of reading the lens position.

After performing the lens position reading process in S205, the process proceeds to S206, where 1 is substituted into the signal SEL of the selector 63b of the control selection circuit 63, and the selector 63b
Is switched to the lens position storage circuit 63a,
After outputting the lens position before the color shift, the processing from S202 is repeated.

On the other hand, if it is determined in S202 that there is no color shift and the process proceeds to S207, it is determined whether or not flagA = 1. If flagA = 1, the process proceeds to S208 and returns to the start. Then, the process proceeds to S209, where the signal SEL of the selector 63b of the control selection circuit 63 is set to 0.
Is input and the lens position at which the focus evaluation value becomes the maximum value is output, and then the processing from S201 is repeated. Also,
In the above S207, when flagA ≠ 1, if the above S
The process jumps to step S209, and after step S209, the process from step S201 is repeated. Thus, the liquid crystal lens 23 is controlled by the liquid crystal lens drive circuit 40 by the signal of the control selection circuit 63.

As described above, according to the second embodiment of the present invention, not only a focus can be obtained when there is no color shift, but also
When there is a color shift, the color shift detecting circuit 62 prevents the liquid crystal lens 23 from being forcibly driven with respect to a rapidly moving subject. For this reason, there is obtained an effect that it is easier to observe a subject that moves rapidly, such as when the endoscope is inserted or the lower part is inserted, than the conventional endoscope apparatus.

[Supplementary Notes] (1) A focus-adjustable endoscope for imaging a subject, light source means for supplying illumination light to the endoscope, and image signals from the endoscope are processed into video signals. Video signal processing means, aperture control means for controlling the amount of illumination light from the light source means, light quantity change detection means for detecting a light quantity change by the aperture control means, and a focus evaluation value from a signal of the video signal processing means A focus evaluation value calculating means for determining the endoscope, and a focus adjustment control means for controlling the focus adjustment of the endoscope based on the focus evaluation value when the light amount change from the light amount change detecting means exceeds a set range. An endoscope device characterized by the above-mentioned.

(2) There is provided a motion detecting means for detecting a motion exceeding the relative setting between the endoscope and the subject, and when the motion exceeding the relative setting is detected, the focus adjustment is performed. 2. The endoscope apparatus according to claim 1, wherein control of the control means is maintained in a state before the movement equal to or more than the relative setting.

(3) The endoscope apparatus according to additional item 1 or 2, wherein the motion detecting means detects a state in which the color of the image pickup signal is separated as a degree of motion.

[0055]

As described above, according to the first aspect of the present invention, when the light amount change exceeds the set range, the focus adjustment of the endoscope is controlled based on the focus evaluation value.
An excellent effect is obtained in that unnecessary focusing can be eliminated as much as possible and a natural and easy-to-view image can be provided to the observer. At this time, as shown in the invention of claim 2,
When a movement exceeding the relative setting between the endoscope and the subject is detected, the control of the focus adjustment control means is maintained in a state before the movement equal to or more than the relative setting, so that the relative setting can be obtained. Unnecessary focusing on the above movement can be eliminated, and a natural and easy-to-view image can be provided to the observer.

[Brief description of the drawings]

FIG. 1 is a block diagram of an endoscope apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the configuration of a focus evaluation value calculation circuit according to the first embodiment;

FIG. 3 is a flowchart of focus adjustment control according to the first embodiment;

FIG. 4 is a block diagram of an endoscope apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a control selection circuit according to the first embodiment;

FIG. 6 is a flowchart of focus adjustment control according to the control selection circuit;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Endoscope apparatus 10 Light source device (light source means) 11 Lamp 12 Rotating filter plate 13 Aperture 14 Aperture control circuit (Aperture control means) 20 Endoscope 21 Light guide 22 CCD 23 Liquid crystal lens 30 Processor (Video signal processing means) 31 CCD drive circuit 32 pre-processing circuit 34 signal processing circuit 36 photometric circuit 37 focus evaluation value calculation circuit (focus evaluation value calculation means) 38 light quantity change detection circuit (light quantity change detection means) 39 lens control circuit (focus adjustment control means) 40 liquid crystal Lens drive circuit 50 monitor

Continued on the front page F term (reference) 2H040 BA06 CA07 CA10 CA11 CA13 2H051 AA00 BA47 BA70 CE14 DA21 DA22 EA05 EA11 EA20 EB01 EB04 FA47 FA48 4C061 AA00 BB01 CC06 DD00 FF40 HH28 LL01 MM02 NN01 PP13 QQ09 RR02

Claims (2)

[Claims] 1. An endoscope having an adjustable focus for imaging a subject, light source means for supplying illumination light to the endoscope, and video signal processing means for processing an image signal from the endoscope into a video signal. Aperture control means for controlling the amount of illumination light from the light source means; light quantity change detection means for detecting a light quantity change by the aperture control means; and focus evaluation for obtaining a focus evaluation value from a signal of the video signal processing means. Value calculation means, and focus adjustment control means for controlling focus adjustment of the endoscope based on the focus evaluation value when a change in light amount from the light amount change detection means exceeds a set range. Endoscope device. 2. The apparatus according to claim 1, further comprising a motion detecting unit configured to detect a motion of the endoscope and the subject that is greater than a relative setting. 2. The endoscope apparatus according to claim 1, wherein the control of the means is maintained in a state before the movement of the relative setting or more.