JPH0368330A - Electronic endoscope device - Google Patents

Abstract

PURPOSE:To execute high-precise servo control by a method wherein a motor control circuit to control the number of revolutions of a rotary color filter at a specified speed divides a reference clock in two different division ratios to control a speed and a phase. CONSTITUTION:A title device comprises a surface sequential light source device 3 to output illumination light of different wavelength areas, an electronic endoscope 2 having a photographing means to photograph a field 17 illuminated with illumination light, a control means 4 to process a signal from the photographing device, and a color monitor 5 to display an output signal from the means 4. The number of revolutions of a rotary color filter 73' mounted in the device 3 is controlled to a specified speed by means of a monitor control circuit 27. The circuit 27 divides a reference clock in two different division ratios, a speed is controlled in a first division ratio by means of a means formed with a 1/6 division passage 44 and a speed control circuit 77, and a phase is controlled in a second division ratio by means of a means comprising a pulse generating circuit 43 and a phase comparing circuit 84. As a result, high-precise servo control can take place.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic endoscope device in which the rotation speed of a rotating color filter of a light source device can be changed.

[Prior Art] In recent years, electronic endoscopes using solid-state imaging devices as imaging means have become widely used.

In endoscopes, it is difficult to increase the resolution because the insertion section needs to be made small in diameter.

Therefore, the field sequential method, in which illumination light in different wavelength ranges is sequentially emitted through a rotating color filter and the image signals of each color captured under each illumination light are combined to create a color image, is similar to white illumination. This method has the advantage that a color image with r1 resolution can be obtained compared to a simultaneous type that performs color photography using an imaging means equipped with a color filter.

In the above-mentioned field sequential method, a servo system proposed in Japanese Patent Application No. 63-44705N, for example, may be used to rotate the rotating color filter at a constant speed.

FIG. 6 shows a conventional motor control circuit 70 that more specifically shows the above proposal.

The motor drive circuit 71 rotates the motor 72,
A rotary filter 73 (R, G B ) in which R, G, and B color transmission filters 73R, 73G, and 73B are provided in the circumferential direction rotates. Therefore, the white light from the lamp 74 passes through the rotating filter 73 and becomes R, G, and B light in sequence, and is condensed by the condensing lens 75 to form the light guide 7.
Leads to 6.

When the motor 72 rotates, the F provided in the motor 72
A G pulse is output from the G (frequency oscillator) 72A. This is due to the electromotive force generated by the rotation of the magnet inside the motor.
It shall be able to output 25 shots per rotation. If the rotational frequency of the motor 72 is f, then the frequency of the FG72A is 2.
It becomes 5fHz. The FG output is input to a speed 1-1 m circuit 77. speed! 11 control circuit 77 includes a 1/4 frequency divider 79 for the 4fsc frequency clock of the 4fSC oscillator 78.
f sc (subcarrier, NTS
In the case of C, the clock of 3.58Mth l) is input, and fsc says "Count the period of G pulse. Speed 1".
．． II open circuit 77 has a configuration as shown in FIG.

The counter 80 is preset at the falling edge of the FG pulse. The Bricht value is predetermined in ROM.
The value is 81. From now on, calculate the period fse until the falling edge of G72A.
It goes down. The D/A circuit 82 converts the output from the clock 1 to an absolute log voltage, which is latched by the latch circuit 83 at the falling edge of FG to become a speed error voltage. The speed error voltage is added to the phase error voltage output from the phase comparator circuit 84 by an adder 85 and then sent to the motor drive circuit 71.
is output to. For example, if the rotational frequency of the motor 72 is f=30H2 when the speed error voltage is VFG, then F
Set the preset value U so that the voltage level is VFG when the frequency of G72A reaches 25 x 30 = 750 ROZ.
It is determined. FG 72 A frequency is 750H
When it deviates from z, the speed error voltage deviates from VFG, and by inputting that voltage to the motor drive circuit 71, the rotation speed of the motor 72 is changed, and the frequency of FG 72A is controlled so as to return to 750H2. .

Next, the phase system will be explained. By rotating the rotary filter 73, an exposure period during which light passes and a shielding opening during which light is blocked are established. During the shielding period, a vP (video processor device) reads out the charges accumulated in the COD during the exposure period and generates a video signal. Therefore, it is necessary to time the video signal and the rotation of the rotary filter 73. A silk (shaped copper part) 86 is attached to the rotary filter 73, and by reading this with a reflector (such as a photoreflector) 87, a 5TART signal shown in FIG. 9(a) is generated. The rotation phase of the rotary filter 73 can be read from the 5TART signal. ST A RT signal and 'from VP'
The 1/D signal (!!!direct signal) and fsc are input to the phase comparator circuit 84. The phase comparator circuit 84 is constructed as shown in FIG. The "1vD signal shown in FIG. 9(b) is converted into a vertical voltage of 30 units by the mask circuit 91 as shown in FIG. 9(c).The falling edge of this signal VD' The counter 92 is britched at this point. This britching value is a predetermined value in the ROM 93. At the falling edge of the 5TART signal, counting starts using fsc as the clock, and counting continues until the next falling edge of the signal VD'. The counted output is converted to an analog voltage by the D/A circuit 94, and the latch circuit 9
5, it is latched at the falling edge of the signal VD' and becomes a phase error voltage. When the phase error voltage is VPG, 5TA
The falling edge of the RT signal is aμ more than the falling edge of VD'.
If it is before sec, the preset value is determined so that VPG is obtained when the phase relationship is a Llsec. [l!
The phase relationship is controlled so that the phase relationship returns to aμsec by changing the number of rotations.

[Problems to be Solved by the Invention] When rotating the rotary filter 73 with 30 ports, the method described in the conventional example shown in FIG. 6 may be used.

However, in the case of the frame sequential method, the exposure period cannot be increased because the light shielding period is determined as the time required to read out the CCD. Then, the exposure is not sufficient and S
There was a problem in that the resulting image had a low /N value.

Therefore, it is conceivable to reduce the rotation frequency and increase the exposure time. However, when trying to configure a servo system as in the prior art, this also causes various inconveniences because the contents of the ROM must be restored.

Furthermore, if an attempt was made to apply an analog servo (which does not require a ROM) instead of a digital servo, there was a problem in that the accuracy of the phase cycle would not be achieved.

The present invention has been made in view of the above points, and f'
It is an object of the present invention to provide an electronic endoscope device that can change the rotation frequency of a color filter without changing the contents of a ROM and can perform highly accurate control.

[Means and effects for solving the problem] In the present invention, in order to rotate the rotary color filter at 20 Z (rotations), the clock input to the speed control circuit is changed from fsc in the case of 301-IZ to 2/3 fsc. In addition, indicators representing the filter position are provided at equal intervals on the rotating color filter, and by reading them with a sensor, a 30 Hz signal is generated and synchronized with the vertical synchronization signal. , the same R as in the case of 30Hz
It is possible to use OM. Also 10H
When rotating in z, a servo system with g accuracy is realized using a similar method. Roughly by clock switching means.

Different rotation speeds can be achieved with the same circuit configuration.

[Example] Hereinafter, the present invention will be specifically described with reference to the drawings.

Figures 1 to 4 relate to the first embodiment of the present invention.
The figure shows the configuration of the morph 1tllt[1 circuit in the first embodiment, FIG. 2 shows an operation explanatory diagram of the motor υl111 circuit, FIG. The overall configuration of one embodiment is shown.

As shown in FIG. 3, the electronic endoscope device 1 of the first embodiment includes an electronic endoscope 2 equipped with an m-image means, and an electronic endoscope 2 equipped with an m-image means.
A light source device 3 that supplies illumination light to the camera, and a control system that performs signal processing for the imaging means @li! ? (video processor) 4, and a color monitor 5 for displaying the video signal output from this device t11 d4.

In the electronic above? Nm2 has an elongated insertion part 7, and a larger operating part 8 is formed at the rear end of this matchmaker part 7. A universal cord 9 extends from this operating part 8, and a Connect the attached connector 11 to light source drawing 3 and i.
, 11111 device 4.

The operating portion 8 is provided with an angle knob 12, and by rotating this knob 12, the +Jh portion 14 adjacent to the tip portion 13 can be curved.

By connecting the connector 11 above, a light source! ! Light guide 15 inserted through Niversal cord 9 from i direct 3 to co
Illumination light is supplied to the end face of the intermediary unit 7 and is emitted from the end face on the distal end portion 13 side of the intermediary portion 7 roughly through the illumination lens 16 to the subject 17 side.

As shown in FIG. 4, an optical image of the illuminated object No. 17 is focused on a CCD 19 disposed at its focal plane by a four-digit objective lens 18 attached to the tip 13. This CCD
19 is supplied with a CCD drive signal from the CCD driver 21 in the AI control stirrup 4, and a photoelectrically converted signal is output to the video signal +-3rj8 logic circuit 22. A standard video signal is generated by the video signal processing circuit 22, and the subject image is displayed in color on the color monitor 5 via the cable 23.

Of the above video signals, the vertical synchronization signal component is connected to the cable 24.
By connecting the connector 25 provided at one end, the light is transmitted to the light source device 3 connected to the connector 26 provided at the other end.

By connecting the connector 26, a vertical synchronizing signal is input to the motor control circuit 27.

In this embodiment, the light source device 3 uses a motor movement control circuit 32 to control an RGB filter unit 31 for outputting surface sequential light so that it can selectively output white light and RGB surface sequential light. It can be freely inserted and removed on the illumination optical path between the lamp 74 and the condensing lens 75. This motor movement tllt11 circuit 32 is controlled by the CPU 33. Also, this CPU 33 emits pulsed light i! Controls the III control circuit 34 and drives the lamp 74 through the lamp drive circuit 35.
emits pulse light.

By the way, the motor 72 of the RGB filter unit 31 is powered by i! 141 vertical plane 19 from tll device 4] signal V
By the motor control circuit 27 inputted to Difi,
The timing of reading the charge of CCD 19 and the R, G, B
The rotational speed and phase are restricted by the signal VD so that the timing is always synchronized with the emitted light.

The configuration of the motor IJ a11 circuit 27 is shown in FIG.

The RGB rotary rotary filter 73' attached to the rotating shaft of the motor 72 is provided with cycle-shaped irregular portions 41r, 410, 41b at three equal intervals on its concentric circle, and the opening period of each filter 73R, 73G, 73B is It is an indicator of

Further, the sensors 42a and 42b arranged opposite to each of the irregular portions 41r, 41g, and 41b are waveform-shaped by a pulse shaping circuit 43 and inputted to a phase comparison circuit 84.

The output signal of the 41" SC oscillator '78 is frequency-divided by 1/6 by the 1/6 frequency divider 44 and input to the "fA degree control circuit 77, and the output signal of the G72A corresponding to the rotation of the motor 72 is Outputs the speed error voltage with the G pulse.

In this case, the speed control circuit 77 receives the sixth signal as a single standard signal.
In the case of the figure, the output of the 174 frequency divider 79 (Yonaku, 1/6
Since the output of the frequency divider 44 is input, the motor 72 is
A speed error voltage is output when the rotation speed deviates from 4/6 (=2/3) of the rotation, that is, 20 rotations per second.

On the other hand, since the output signal of the 1/4 frequency divider 79 is input to the phase comparator circuit 84, the phase error voltage
It is similar to the figure.

The rest of the configuration is the same as that in FIG. 6, and the same components are designated by the same reference numerals.

The operation of this device will be explained first from the speed system.

When the number of rotations of the rotary filter 73 is 20 ports 2, FG
Frequency of 72A [yo, 25 x 20 = 500H
It becomes z. This FG pulse, together with the 2/3fsc clock frequency divided by the 1/6 frequency divider 44, has a speed of tI11.
111 circuit 77.

In this case, the counter 80 is preset at the falling edge of the FG pulse. This preset value is a predetermined R
This is the value of OM81. That is, this value is the same as that of the conventional example shown in FIG. However, since the frequency of the reference clock has become 2/3, when the frequency of the FG pulse deviates from 500 Hz, the speed error voltage becomes VFG. When the frequency of the FG pulse deviates from 500 t-1z, the voltage deviated from the speed error voltage VFG is input to the motor drive circuit 71, and the rotation speed of the motor 72 changes, causing the frequency of the FG pulse of FG 72A to change. frequency is 500
It will return to Hz. In this way, the rotation frequency of the rotary filter 73' is controlled to be maintained at 20 points Z.

Next, the phase system will be explained. Anti-copper parts 41r and 41q provided on concentric circles of the rotary filter 73'.

41b is read by the sensor 42a and 42br, as shown in FIG.
) is output.

This 5TART signal is passed through the rotary filter 73' to 201-1.
If it is rotating at 2, its frequency is 60! -＋Z
, and the duplex synchronous communication shown in Figure 2(C)''4 V D
It has the same frequency as .

This 5TART signal is input to the pulse shaping circuit 43, and as shown in FIG. 2(b), this pulse shaping circuit 43-
Outputs a signal @b which is the QST A RT signal decimated to 1/2. This signal is input to the phase comparator circuit 84, and the 1J60 Hz vertical plane transmitter vD shown in FIG. 2(C) is thinned out by the mask circuit 91 (see FIG. A phase error voltage is generated with the synchronization signal VD'. This effect was explained in the conventional example. In other words, the ROM 73 with the same contents can be used in this case as well.

In this first embodiment, ROM 81.93 of the control system for rotating the motor 72 at 30 Hz is used as is,
Speed ffi control and phase a control can be performed with precision even at 20 Hz.

FIG. 5 shows a motor control circuit 5 in a second embodiment of the present invention.
The configuration of 1 is shown.

In FIG. 1, this motor control circuit 51 includes a speed control circuit 77, a clock switching circuit 52, a 1/6 frequency divider 4. The clock passed through /l and the clock passed through the 1/4 frequency divider 79 can be selected and output. For example, when the contact point S1 is selected, the rotary filters 73 are all rotated 12.11 so that the same rotation speed is 20 l, as in the first embodiment.

On the other hand, when the contact S2 is selected, the rotational speed of 30 Hl is controlled. In this case, the reflecting section 4
1', 41o, and 4.1b are made into one reflecting part 86 as shown in FIG.

That is, since the f'sc clock frequency divided by the 1/4 frequency divider 79 is input to the speed control circuit 77, the speed of the rotary filter 73 is controlled by 301-1z as described in the conventional example. Ru. If the phase is to be controlled by roughly 30 tl z, the phase control can be achieved by using a reflecting section 86 as shown in 4.1 and FIG. 6. (In this case, the pulse shaping circuit 4
In step 3, only pulse shaping is performed. ) Therefore, by providing the clock switching circuit 52, speed control and phase 1 to 30Hz and 20H7 can be easily controlled with the same circuit without changing the ROM. It is difficult to understand.

In the second embodiment, when the contact S2 is selected for the clock switching circuit 52, a switching control means may be provided such that the output of the reflecting section 41 is inputted to the phase comparator circuit 84. As for this switching control circuit, for example, the sensor 142a detects the reflective parts 41r, 41a, 41b, while the sensor 42b detects, for example, only the color filter 73R, and the logic of these sensors 41a, 41b is The output from the AND circuit that obtains the product is sent to the phase comparator circuit 8.
It is sufficient to follow the configuration as input in 4.

In addition, the COD driver 21 and the video signal processing circuit 22 may also be switched in conjunction with the above switching.

In addition, when the rotary filter 73' is to be rotated by 10 ports Z, a 1/1 frequency divider 44 is used instead of the 1/6 frequency divider 44 in FIG.
It is sufficient to use a 2 frequency divider and input the 5TART signal as it is to the phase comparator circuit 84.

Similarly, it is also possible to control to other rotational speeds.

Note that the rotating filter is not limited to one that combines R, G, and eight-color filters, but may also be constructed using complementary color filters and other color filters.

Incidentally, the present invention can be similarly applied to a doublet type endoscope in which a frame sequential type television camera is attached to the eyepiece portion of the optical endoscope.

[Effect of explanation] As described above, according to the present invention, the input to the speed control system [instead of dividing the frequency of the cock into 1/4,
By using a frequency divider or the like, the rotation of the rotary filter can be controlled by 201-1z or the like. or,
By reading indicators such as the reflection part of the rotating filter and performing pulse shaping '8, the Shingetsu of 301-(z can be generated,
It can be phase synchronized with vertical synchronization Shingetsu. Furthermore, since a 1-nervo system can be configured digitally, high M degree control can be performed.

[Brief explanation of drawings]

FIGS. 1 to 4 relate to a first embodiment of the present invention.
2 is a block diagram showing the configuration of the motor control circuit, FIG. 2 is an explanatory diagram of the operation of the motor control circuit, FIG. 3 is an external view of the first embodiment, and FIG. 4 is an overall configuration diagram of the first embodiment. FIG. 5 is a block diagram of the motor control circuit in the second embodiment of the present invention, FIG. 6 is a block diagram of the motor control circuit in the conventional example, and FIG. 7 is a block diagram of the speed control circuit 1 in FIG. 8 is a block diagram of the phase comparison circuit of FIG. 6, and FIG. 9 is an explanatory diagram of the operation of FIG. 6. 1... Endoscope equipment purchase 2... Electronic endoscope 3...
・Light source equipment 1 4...1lIII control circuit 5...
・Color monitor 27...Motor control circuit 4.1
r, 41g, 41 b--Reflection portions 42a, 42b-
...Sensor 43...Pulse shaping circuit 44...1/6 frequency divider 7
1... Motor drive circuit 72... Motor 9 73'... Rotating filter 7
7...Speed control circuit 78...4fsc oscillator 7
9...1/4 frequency divider 84...Phase comparator circuit Figure (d) 42- Figure 6 Figure 8 Figure (C) Procedural official document (self-proposed) Figure 4 November 1999 Kimi? Day

Claims (1)

[Claims] A field-sequential light source device that outputs illumination light in different wavelength ranges,
an electronic endoscope equipped with an imaging means for imaging a subject illuminated under the illumination light; a control means for processing a signal from the imaging means; and a color monitor for displaying an output signal of the control means. An electronic endoscope device comprising: a motor control circuit for controlling the rotation speed of a rotating color filter provided in the light source device to a constant speed; Divide the frequency by the frequency ratio, and
An electronic endoscope apparatus comprising a control means for controlling the speed using a frequency division ratio and controlling the phase using a second frequency division ratio.