JP2969522B2 - Electronic endoscope device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic endoscope apparatus having a dimming control circuit.

[Problems to be Solved by Related Art and Invention] In recent years, various endoscopes using a solid-state imaging device such as a charge-coupled device (CCD) have been proposed. In such an endoscope, a method of providing a color filter integrally with or separately from a CCD and a method of sequentially switching light of three primary colors and irradiating the CCD are known. For details of these structures, see, for example,
-65962 and JP-A-55-54933.

The details of the prior art relating to the dimmer of these devices are described in, for example, Japanese Patent Application Laid-Open No. 61-58888 by the present applicant.

FIG. 7 and FIG. 8 show the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 61-58888. The light control device will be described with reference to FIG.

In the figure, a signal from a solid-state imaging device (hereinafter abbreviated as CCD) 4 provided on the distal end side of the endoscope insertion section 2 is illuminated through a series connection of a preamplifier 23 and a video amplifier 24. The signal is guided to an automatic light control first signal detection terminal 25 and supplied to a gain control means 22 connected to a stage subsequent to the first light detection terminal 25.

The illumination means 21 is divided into a circuit section 21a and an optical section 21b.
Reference numeral 21a designates a dimming control signal S1 formed based on a signal from the first detection end 25 as a drive signal for the galvanic motor 26 of the optical unit 21b. The output shaft of the galvano motor 26 drives an aperture member 27 that dims the illumination light from the light source unit 12. The illumination light whose light amount has been adjusted by the aperture member 27 is incident on a condenser lens system 28. The light passing through the condenser lens system 28 is focused at the position of the slit 29, enters the incident transmission lens system 30 arranged near the rear of the slit 29, and becomes illumination light having a predetermined width. This illuminating light is incident on the exit end transmission lens system 33 via the three primary color rotating filters 32 shown in FIG. 8 which are driven to rotate by the synchronous motor 31, and the output light is introduced into the entrance end of the light guide fiber 9. Is done. In addition,
The synchronous motor 31 has a servo circuit 34, and rotates the rotary filter 32 in a predetermined direction at a predetermined constant speed. The rotation filter 32 detects the start pulse indicating the rotation start position and the R, G, and B light-shielding portions for reading by the rotation detector 35 so that the read pulse indicating the reading start position from the CCD 4 is detected. It has become. This detector 35
The signal detected by is supplied to the timing generator 36 and controls the same.

On the other hand, the circuit section 21a of the illumination means 21 introduces a signal derived from the detection end 25 to one end of three series resistors R1, R2, R3. The other ends of the series resistors R1, R2, and R3 are connected to a ground point, and the one end PG and each intersection PR,
PB is supplied to a three-input analog switch 37. The signal levels of each of PR, PG, and PB supplied to the analog switch 37 are sequentially set to levels that match the relative luminous efficiency characteristics of green light, red light, and blue light. Is available. That is, the timing generator 36 receiving the pulse detected by the rotation detector 35
Is R, by the start pulse and the read pulse.
A switching pulse S2 is generated for each of G and B,
The position of the analog switch 37 is switched and set by the switching pulse S2. Thus, the output of the analog switch 37 switched every three primary color signal periods is supplied to the first input terminal of the first comparison amplifier 39 via the low-pass filter 38. The second input terminal of the first comparison amplifier 39 has CC
A reference voltage source that supplies a voltage Vr1 corresponding to the lowest average value that can tolerate the dynamic range of the D output signal is connected, and the average value (luminance signal) of the signal from the analog switch 37 during each of the three primary color signal periods. Is lower than Vr1, the first comparison amplifier 39 can apply the dimming control signal S1 to the galvanic monomotor 26.

Next, the gain control means 22 receives the signal of the first detection terminal 25 in the multiplier 40, and guides the output of the multiplier 40 to the second detection terminal 41. The signal of the second detection terminal 41 is supplied to the color TV monitor 8 via the TV signal conversion unit 7 and is displayed thereon, and is introduced into one end of a series circuit including resistors R4, R5, and R6. The other end of the series circuit is connected to the ground point, and the signal at one end QG and the intersections QR and QB are introduced to the analog switch 42, respectively. The same switching pulse S2 as that of the analog switch 37 on the illuminating means 21 side is applied to the analog switch 42 to perform the switching control. The signal selected by the analog switch 42 is passed through the low-pass filter 43 to the second switch 42. The signal is supplied to a first input terminal of the comparison amplifier 44. A reference voltage source for supplying a voltage Vr2 is connected to a second input terminal of the second comparison amplifier 44. This signal Vr2 is set to a voltage corresponding to the minimum luminance signal level that allows the dynamic range of the signal passed through the multiplier 40, that is, the signal subjected to dimming control, and the level of the signal from the low-pass filter 43 is set. When the voltage falls below Vr1, the gain of the multiplier 40 can be controlled.

FIG. 8 shows the aforementioned rotary filter 32, 32B, 32G,
32R is blue light, green light,
This is a filter part that transmits red light. A light-shielding portion 32CB, 32CG, 32CR is provided between each filter portion. For example, a period in which the subject is irradiated with predetermined primary color light by being rotated once during each successive field period, and an intermediate period between these periods. A light-shielding period can be created. Reference numeral 45 denotes a through hole for detecting a start pulse of the rotary filter 32. Reference numerals 46R, 46G, and 46B are through holes for detecting read pulses for reading R, G, and B video signals. This start pulse is generated at the start of each field period.

In the endoscope device configured as described above, the rotation filter
The illumination light for which the light-shielding period and each of the three primary color light periods are set by 32 transmits the emission side transmission lens system 33, the light guide fiber 9, and the light distribution lens system 14 to illuminate the subject. The image light energy corresponding to the repetition of the period is irradiated. As a result, the video signal read from the CCD 4 is guided to the second detection terminal 25 via the preamplifier 23 and the video amplifier 24, and a part is connected to the multiplier 40 and a part is connected to the series resistance of the illumination means 21 side.
Introduced into R1, R2, R3. Thus, for example, during the red signal period, the analog switch 37 outputs the red signal of the voltage division level set at the intersection PR of the resistors R1 and R2 to the low-pass filter of the next stage.
The low-pass filter 38 supplies the average value of this signal to a first input terminal of a first comparison amplifier 39. At this time,
When the average value is smaller than the reference voltage Vr1, the first comparison amplifier 39 generates the dimming control signal S1 and
Thus, the aperture of the aperture member 27 is widened, so that the amount of illumination light from the light source unit 12 increases.

As described above, the dimming circuit and the gain control circuit shown in the prior art operate so that the CCD output level becomes constant.

On the other hand, a function of a parent-child screen for displaying a plurality of screens in a TV receiver or the like is disclosed in, for example, Japanese Patent Publication No. 54-22050. This technique is a diagnostically useful technique for an electronic endoscope. In this technique, an image is reduced on a small screen. In recent years, an electronic endoscope apparatus has been proposed which has a function of displaying an enlarged image. This is becoming an increasingly important feature in the development of small, high pixel CCDs.

In general, when performing enlargement or reduction of an image, an enlargement / reduction circuit is provided after the automatic light control circuit and the automatic gain control (AGC) circuit shown in FIG. Irrespective of the light control. That is, for example, even if a bright portion and a dark portion are images and the amount of light is appropriate for the entire image, when a bright portion of the image is enlarged, only the enlarged portion is not dimmed. The entire screen of the monitor may become bright, resulting in an image that is very difficult to see.

The present invention has been made in view of the above circumstances, and ensures that an image is always displayed with appropriate brightness even when an image on the screen of an observation monitor is enlarged or reduced, so that a high It is an object of the present invention to provide an electronic endoscope apparatus which can ensure a constant brightness with respect to the size of a light or the like and can always display an accurate and easy-to-view image with high diagnostic performance on an observation monitor.

[Means and Actions for Solving the Problems] An electronic endoscope apparatus according to the present invention includes: an illumination unit configured to generate illumination light for irradiating a subject; an imaging unit configured to image the subject and output an imaging signal; Display means for displaying an image of the subject based on the image pickup signal from the image pickup means, and an image signal corresponding to a first image pickup area on the image pickup means among the object images picked up by the image pickup means Switching means capable of instructing a first display and a second display based on an imaging signal corresponding to a second imaging area different from the first imaging area, and the imaging based on an instruction signal from the switching means Signal processing means for processing the imaging signal output by the means and outputting a signal including a video signal component corresponding to an imaging area corresponding to the display instructed by the switching means;
A video signal generating unit that generates a video signal for displaying the subject image on the display unit based on an output signal from the signal processing unit; and the lighting unit generates the video signal based on an output signal from the signal processing unit. Light control means for controlling the amount of illumination light.

[Example] Hereinafter, a specific description will be given with reference to the drawings of the present invention.

1 to 3 relate to a first embodiment of the present invention. FIG. 1 is a block diagram of an electronic endoscope apparatus, and FIG. 2 is a case where an automatic dimming circuit is provided in front of an enlargement / reduction circuit. FIG. 3 is an explanatory diagram of a display image when an automatic dimming circuit is provided at a subsequent stage of the enlargement / reduction circuit.

The sixth embodiment is different from the sixth embodiment except that the configuration of the TV signal converter 7 is different, the signal from the TV signal converter 7 is input to the circuit section 21a of the illumination means 21, and the gain control means 22 is not provided.
It has the same configuration as the prior art shown in FIG. 7 and FIG. 6 and 7 are denoted by the same reference numerals, and description thereof will be omitted.

Solid-state imaging device 4 provided on the distal end side of endoscope insertion section 2
R, G, B sequential signals from the
And is supplied to the TV signal conversion unit 7.

The TV signal converter 7 includes a pre-processing circuit 47, and a signal from the video amplifier 24 is input to the pre-processing circuit 47. The pre-processing circuit 47 extracts the video signal, γ
Correction and the like are performed and output to the A / D converter 48. After the signal digitized by the A / D converter 48 is interpolated or thinned out by the enlargement / reduction circuit 49, the R signal is stored in the memory 50R.
The G signal is written to the memory 50G, the B signal is written to the memory 50B and read simultaneously, and the output of the memory 50R is D / A
In the converter 51R, the output of the memory 50G is converted into an analog signal by the D / A converter 51G, and the output of the memory 50B is converted into an analog signal by the D / A converter 51B.
The synchronized R, G, and B signals are branched, one of which is provided to a post-processing circuit 52, and the other is provided to a lighting means 21 as a light control means.
Supplied to In the post-processing circuit 52, R, G, B
The signal is converted into, for example, an NTSC video signal and output to the observation monitor 8 to display a subject image on the monitor 8.

On the other hand, in the illumination means 21, R, G, and B signals are input to each input terminal of the analog switch 37.

 Hereinafter, the configuration is the same as in FIGS. 6 and 7.

When observing a subject without enlarging or reducing it with the endoscope apparatus configured as described above, the signal from the solid-state imaging device 4 passes through the amplifier 23 and the video amplifier 24 and is converted into a video signal by the pre-processing circuit 47. The data is extracted and digitized by an A / D converter 48, passes through an enlargement / reduction circuit 49, and stores the memories 50R, 5R.
After being written to 0G and 50B, they are simultaneously read and converted into analog signals by the D / A converters 51R, 51G and 51B. The analog signal is output to the observation monitor 8 via the post-processing circuit 52 and is also input to the circuit section 21a of the illumination means 21 to perform dimming.

Here, when the current observation is a far-point observation, a large amount of light is required, so that the aperture of the diaphragm member 27 widens and a large amount of illumination light is emitted from the light guide fiber 9 to the subject. As a result, as shown in FIG. 3A, the highlighted portion of the display image on the observation monitor 8 becomes white. When the near end observation is performed by bringing the distal end of the endoscope insertion portion 2 close to the subject, on the contrary, the amount of illumination light is too large and the aperture member 27 is stopped down, and the display on the observation monitor 8 is displayed as shown in FIG. The highlight part of the image is gray.

Next, when the image shown in FIG. 7A is enlarged by the enlargement / reduction circuit 49 and becomes the same image as the image shown in FIG. The dimming control is performed on the basis of the image enlarged to be supplied to the camera. For this reason, when the highlighted portion in white in FIG. 9A is enlarged, it becomes gray as shown in FIG. 9C and becomes the same as the display image in FIG.

On the other hand, a signal input to the circuit section 21a is enlarged / reduced by a circuit 49.
2 is displayed as shown in FIG.

FIG. 2A shows a display image on the observation monitor 8 when a far-point observation is performed. In this case, the highlight portion is white as in FIG. FIG. 2B shows a display image when the same subject is observed at a near point. 2 (a) and 2 (b) are displayed in the same manner as FIGS. 3 (a) and 3 (b). However, when FIG. 2 (a) is enlarged, the enlarged video signal is not input to the circuit unit 21a, and the unenlarged video signal is input to the circuit unit 21a. 2 The highlighted portion of the enlarged image shown in FIG. 2 (c) becomes white, making the image difficult to see.

As described above, in this embodiment, the circuit unit 21a is connected to the subsequent stage of the enlargement / reduction circuit 49, and the image on the observation monitor 8 enlarged or reduced to perform dimming based on the signal subjected to the enlargement / reduction processing. It can be suitable.

4 and 5 relate to a second embodiment of the present invention. FIG. 4 is a block diagram of a TV signal converter, and FIG. 5 is a timing chart for explaining the operation.

In the TV signal converter 7 of this embodiment, the output of the pre-processing circuit 47 is branched, one of which is output to the A / D converter 48 and the other is output to the second converter.
Each is connected to an iris detection circuit 56. A / D converter 4
The output of 8 is connected to an enlargement / reduction circuit 49, and the output of the enlargement / reduction circuit 49 is connected to memories 50R, 50G, and 50B (shown as one block in the figure). Each memory 50
R, 50G, and 50B are connected to D / A converters 51R, 51G, and 51B (shown as one block in the figure), and D / A converters 51 are provided.
The outputs of R, 51G, and 51B are branched, and one is connected to the post-processing circuit 52 and the other is connected to the first iris detection circuit 53.

The first and second iris detection circuits 53 and 56 have the same configuration as the circuit section 21a described in the first embodiment.

The output of the second iris detection circuit 56 is connected to one input terminal of an analog switch 55, and the output of the first iris detection circuit 53 is connected to the other input terminal of the analog switch 55.

An output terminal of a timer 54 is connected to a control terminal of the analog switch 55 to which a switching control signal is input, and the timer circuit 54 receives a freeze control signal by a front panel or a scope switch together with the memories 50R, 50G, and 50B. It is supposed to be. Memory 50
R, 50G, and 50B inhibit the writing of a new video signal when a freeze control signal is input, repeatedly output the already written image signal, and release the write inhibition after a preset time has elapsed. Has become. A shorter time is set in the timer circuit 54 than the time set in the memories 50R, 50G, and 50B.The timer circuit 54 starts counting at the same time that the freeze control signal is input. The control signal of the switch 55 is turned off to select the second iris detection circuit 56 side, and after turning off for a certain time, turned on again to select the first iris detection circuit 53 side.

The operation of the endoscope apparatus configured as described above will be described with reference to FIG.

First, in the case of a normal image that has not been enlarged or reduced, if the image is not frozen, the output signal from the timer circuit 54 is on, whereby the analog switch 55 switches the first iris detection circuit 53 side. You have selected. Therefore, the optical unit 21b (not shown) performs dimming based on the video signal downstream of the enlargement / reduction circuit 49.

Next, in a normal image, when a freeze control signal is input, the memories 50R, 50G, and 50B inhibit writing of a new video signal, repeatedly output the already written video signal to the observation monitor 8, and freeze the displayed image. I do. Further, the timer circuit 54 starts counting at the same time when the freeze control signal is input, and turns off the output signal after the time t1 has elapsed. This allows analog switches
55 selects the second iris detection circuit 56 side, outputs the output of the second iris detection circuit 56 to the optical unit 21b, and the optical unit 21b performs dimming based on this output.

When the time t2 elapses after the timer circuit 54 is turned off, the memories 50R, 50G, and 50B release the write inhibition and start writing and reading, and the observation monitor 8 displays a moving image. In this case, since the time t2 has elapsed since the automatic light control by the second iris detection circuit 56 was started, the optical unit
The operation of 21b is already stable. Therefore, the display image on the observation monitor 8 displays an image with proper dimming from the time when the freeze image is switched to the moving image.

The timer circuit 54 turns on the output when the time t3 elapses after turning off the output signal, and the analog switch 55 again selects the first iris detection circuit 53 side.

Also, when the enlargement / reduction is performed by the enlargement / reduction circuit 49, the operation is performed in the same manner as described above.

That is, when the freeze is not performed, since the analog switch 55 selects the first iris detection circuit 53 side, the optical unit 21b performs dimming based on the video signal subjected to the enlargement or reduction processing. . When the freeze is performed, the enlarged or reduced image is displayed on the observation monitor 8. Before the freeze is released, the second iris detection circuit 56 operates, and the optical unit 21b performs the enlargement or reduction processing. The light control is started based on the video signal that has not been performed. After the time t2 has elapsed and the operation of the optical unit 21b has stabilized,
The freeze is released. At the same time when the freeze is released, the enlargement / reduction circuit 49 stops the enlargement / reduction processing, and the video signal which has not been subjected to the enlargement / reduction processing is stored in the memory 50.
Output to R, 50G, 50B.

Generally, when the memory has a freeze function, the detection of the iris is always constant when the image is frozen, and the iris is required to operate promptly when the freeze is released. It takes a certain period of time to perform the operation, during which time the brightness of the observed image becomes unstable.

In this embodiment, the enlarged or reduced image is frozen, the second iris detection circuit 56 is operated before the freeze is released, and the operation of the automatic dimming circuit is stabilized when the freeze is released. Because it is possible, the image on the observation monitor 8 at the time of switching from the freeze image to the moving image is displayed by appropriate dimming, and is not difficult to see.

Other configurations, operations and effects are the same as those of the first embodiment.

FIG. 6 is a block diagram of a TV signal converter according to a third embodiment of the present invention.

In the present embodiment, the dimming signal is extracted from the subsequent stage of the enlargement / reduction circuit 49 in the first embodiment.
The output of the pre-processing circuit 47 provided in the preceding stage of 49 is guided to the dimming circuit, the magnification or reduction magnification is detected, and the time constant and the gain of the dimming circuit are switched according to the magnification. It is.

The output signal of the pre-processing circuit 47 constituting the TV signal conversion unit 7 is branched and one is guided to the A / D converter 48 and the other is guided to the iris detection circuit 59. The iris detection circuit 59 is connected to the time constant / gain switching circuit 58 so that the time constant and the gain can be switched. Iris circuit 59
Is output to the optical unit 21b described in the first embodiment.

The enlargement / reduction circuit 49 and the time constant / gain switching circuit 58 are connected to a magnification control circuit 57, and receive a control signal corresponding to the enlargement or reduction magnification from the magnification control circuit 57. The magnification control circuit 57 receives a scope detection or switching signal indicating an enlargement or reduction magnification, and outputs a control signal corresponding to the enlargement or reduction magnification when this signal is input. ing. The scope detection signal is output from a scope detection circuit (not shown) that detects the type of the solid-state imaging device of the endoscope to be used, and the switching signal is input from, for example, a changeover switch provided on the front panel. It is supposed to be.

In the electronic endoscope apparatus configured as described above, when an image on the observation monitor 8 is enlarged or reduced, a scope detection signal or a switching signal indicating an enlargement or reduction magnification is input to the magnification control circuit 57. The magnification control circuit 57 outputs a control signal to the enlargement / reduction circuit 49 and the time constant / gain switching circuit 58 based on the input scope detection signal or switching signal. The enlargement / reduction circuit 49 performs enlargement / reduction processing on the video signal from the pre-processing circuit 47 according to the enlargement / reduction magnification of the control signal.
The gain switching circuit 58 outputs a control signal for adjusting the time constant and gain of the iris detection circuit 59 so that the size of the highlight on the observation monitor 8 matches the detection characteristics of the iris detection circuit 59.

In this embodiment, an iris detection circuit 59 is connected in front of the enlargement / reduction circuit 49 as in the prior art. However, the iris detection circuit 59 uses a time constant / gain switching circuit 58 for inputting an enlargement or reduction magnification to monitor an observation. In order to adjust the time constant or the gain so that the size of the highlight on the display 8 matches the detection characteristic of the iris detection circuit 59, the light amount can be adjusted according to the display image on the observation monitor 8.

Other configurations, operations and effects are the same as those of the first embodiment.

In each of the above embodiments, R, G, and B are described in a so-called plane-sequential system using sequential illumination light. However, the present invention is not limited to the plane-sequential system, and can be implemented even in a simultaneous system. It is. Further, the present invention may be applied to an endoscope apparatus of an external camera type used by being attached to an eyepiece of a conventional fiberscope.

[Effects of the Invention] As described above, according to the present invention, even when an image on the screen of the observation monitor is enlarged or reduced, the image is always displayed with appropriate brightness, so that the image is displayed on the observation monitor. A certain brightness can be ensured for the size of highlights and the like, and an accurate and easy-to-view image with high diagnostic performance can always be displayed on the observation monitor.

[Brief description of the drawings]

1 to 3 relate to a first embodiment of the present invention.
FIG. 2 is a block diagram of the electronic endoscope apparatus, FIG. 2 is an explanatory view of a display image when an automatic dimming circuit is provided in front of the enlargement / reduction circuit, and FIG. 4 and 5 relate to a second embodiment of the present invention. FIG. 4 is a block diagram of a TV signal conversion unit, and FIG. 5 describes the operation. FIG. 6 is a block diagram of a TV signal converter according to a third embodiment of the present invention, and FIGS. 7 and 8 are related to the prior art.
FIG. 7 is a block diagram of an electronic endoscope apparatus, and FIG. 8 is an explanatory diagram of a rotary filter. DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope apparatus, 2 ... Insertion part 7 ... TV signal conversion part, 21a ... Circuit part 21b ... Optical part, 49 ... Enlargement / reduction circuit

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Jun Hasegawa 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside O-Limpus Optical Industry Co., Ltd. (72) Inventor Yudai Nakagawa 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Katsuyuki Saito, Inventor 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Katsuyoshi Sasakawa 2-43-2, Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Inventor Shinji Yamashita 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Co., Ltd. (72) Akihiko Yajima 2-43-2, Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (56) References JP-A-63-155117 (JP, A) JP-A-63-186619 (JP, ) Patent Akira 62-59473 (JP, A) (58 ) investigated the field (Int.Cl. ^6, DB name) G02B 23/24 A61B 1/04 370

Claims (1)

(57) [Claims] An illumination unit configured to generate illumination light for illuminating the subject; an imaging unit configured to capture an image of the subject and output an imaging signal; and displaying an image of the subject based on the imaging signal from the imaging unit. And a first display based on an imaging signal corresponding to a first imaging region on the imaging unit among the subject images imaged by the imaging unit, and the first imaging region A switching unit capable of instructing a second display based on an imaging signal corresponding to a different second imaging region; and processing the imaging signal output by the imaging unit based on an instruction signal from the switching unit; A signal processing unit that outputs a signal including a video signal component corresponding to an imaging region corresponding to the display instructed by the switching unit; and displaying the subject image on the display unit based on an output signal from the signal processing unit. You Video signal generating means for generating a video signal for controlling the light amount of the illumination light generated by the illumination means based on an output signal from the signal processing means. Electronic endoscope device.