JPH09253037A - Electronic endoscope device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use signal processing means in common as much as possible and to prevent the problem of clamping for fixing a black level from being generated in an electronic endoscope device capable of using the endoscope of the image pickup system of either surface sequential system and color single plate system. SOLUTION: A clamping circuit 56 for fixing the black level in respective video signals obtained from the respective image pickup means of the surface sequential system and the color single plate system to a prescribed DC voltage is provided in the common part of the signal processing means 51, 57, 58, 60 and 61 and clamping pulses corresponding to the image pickup system of the endoscope to be used are inputted to the clamping circuit 56.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscope apparatus capable of using both a frame-sequential image pickup device and a color single plate image pickup device.

[0002]

2. Description of the Related Art As a so-called electronic endoscope having a solid-state image pickup device at the tip of an insertion portion, a frame-sequential type using a monochrome image pickup device by sequentially illuminating an object with illumination light of different colors of three primary colors, A single color plate type using an image pickup device in which three color filters are arranged in a mosaic pattern on the incident surface is used.

Since there are merits and demerits between the frame sequential type and the color single plate type, both types can be used properly depending on the purpose of use of the endoscope, etc. However, if a signal processing circuit is prepared for each type, the device cost will be increased. It is costly and extremely economical.

However, both types are the same in that a video signal obtained as an analog signal is once converted into a digital signal and stored in a memory, and then converted again into an analog signal and output to a television monitor. Therefore, there is a device in which both of the signal processing circuits of both systems are made common to reduce the device cost (Japanese Patent Publication No. 7-38844).

[0005]

The video signal obtained by the image pickup device has a signal period called an optical black level (hereinafter, simply referred to as "black level") which is a reference of the black level, and the video signal is digitized. In this case, it is necessary to fix the black level to a predetermined DC voltage. Therefore, a clamp circuit is required.

However, in the frame sequential type and the color single plate type,
The cycle and phase of the black level included in the obtained video signal, the timing at which the black level starts, the period of the black level, etc. are all different, and it is not possible to clamp with the same clamp pulse.

Therefore, conventionally, only a small part of the signal processing circuit portion can be shared between the frame-sequential type and the color single plate type, resulting in an increase in the device cost and an increase in the circuit scale.

In view of the above, the present invention makes it possible to make the signal processing means as common as possible in an electronic endoscope apparatus which can be used for both image-capturing type endoscopes of the frame-sequential type and the color single plate type, and further, the black level. It is an object of the present invention to provide an electronic endoscope apparatus which does not cause a problem of a clamp for fixing a lens.

[0009]

In order to achieve the above object, the electronic endoscope apparatus of the present invention includes a signal processing means for performing signal processing for an endoscope having a color image pickup means of a frame sequential type. And an electronic endoscope apparatus having signal processing means for performing signal processing for an endoscope having a color single-plate color image pickup means and having a part of a circuit of both signal processing means in common. A clamp circuit for fixing the black level in each video signal obtained from each of the image pickup means to a predetermined DC voltage is provided in the common portion of the signal processing means, and corresponds to the image pickup method of the endoscope used. It is characterized in that a clamp pulse is input to the clamp circuit.

The clamp pulse is input to the clamp circuit at the same cycle as the cycle of the black level in the video signal obtained from the image pickup means of the endoscope used and at the same timing as the black level. The clamp pulse may have substantially the same pulse width as the black level period.

Further, an endoscope type detecting means for detecting which of the above-mentioned image pickup systems is used, and a response to a detection result by the endoscope type detecting means. Clamp pulse selecting means for selecting a clamp pulse to be input to the clamp circuit may be provided.

The clamp circuit is commonly used by the frame-sequential signal processing means and the color single-plate signal processing means, and the clamp circuit corresponds to the imaging method of the endoscope used. The clamp pulse supplied to the circuit may be selected.

Alternatively, the clamp circuit is separately used for the frame sequential signal processing means and the color single plate type signal processing means, and the clamp circuit is used according to the imaging method of the endoscope used. The circuit may be selected.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 schematically shows the overall configuration of the electronic endoscope apparatus. In order to connect the frame sequential electronic endoscope 10 and the color single-panel electronic endoscope 20 to the light source device / video processor 30. Two connector receivers 31 and 32 are provided.

At the tip of the insertion portion 11 of the frame-sequential type electronic endoscope 10, at the imaging position of the object by the objective optical system 12,
A solid-state image sensor 13 including a monochrome type CCD (charge coupled device) is arranged.
The endoscope observation image is captured by.

On the other hand, at the tip of the insertion portion 21 of the color single-plate type electronic endoscope 20, a solid-state image pickup device 23 composed of a color single-plate CCD is arranged at the image forming position of the object by the objective optical system 22. The solid-state image sensor 23 captures an endoscopic observation image.

Both electronic endoscopes 10 and 20 are provided with connector portions 14 and 24 which are detachably connected to the connector receivers 31 and 32 of the light source device / video processor 30, respectively.

The connector portion 14 of the frame sequential electronic endoscope 10 can be connected only to the frame sequential connector receiver 31, and the connector portion 2 of the color single plate type electronic endoscope 20 is connected.
4 can be connected only to the color single plate type connector receiver 32.

A drive signal sent from the light source device / video processor 30 to the solid-state image pickup devices 13 and 23 of the electronic endoscopes 10 and 20, and a light source device from the solid-state image pickup devices 13 and 23 of the electronic endoscopes 10 and 20. An image pickup signal or the like sent to the video processor 30 is also inserted into the insertion portions 11 and 21 and the end portions thereof are connected to the connectors 14 and 24.
5 and 25.

From the light source device / video processor 30,
Illumination light is supplied to the illumination light guide fiber bundles 16 and 26 of the electronic endoscopes 10 and 20, and the illumination light is emitted from the exit end of the light guide fiber bundles 16 and 26 toward the subject.

The image pickup signal transmitted to the light source device / video processor 30 by the signal cables 15 and 25 is processed by the processing circuit in the light source device / video processor 30, and the video signal is transmitted from the light source device / video processor 30 to the television monitor 70. Is output to the television monitor 70 and the endoscopic observation image is displayed.

FIG. 3 shows a state in which the connector portion 14 of the frame-sequential type electronic endoscope 10 is connected to the light source device / video processor 30, and the incident end portion of the light guide fiber bundle 16 also serves as the light source device. It is inserted deep into the video processor 30, the signal cable 15 is connected to the light source device / video processor 30 side, and the image pickup signal a is sent to the processing circuit in the light source device / video processor 30.

Further, the connection detection sensor 33 detects whether or not the connector portion 14 is connected to the connector receiver 31, and the detection signal g is sent to the processing circuit in the light source device / video processor 30.

As the connection detecting sensor 33, a reflection type photo interrupter 1 is used here, and the connector unit 1 is used.
The projection 19 attached to the fourth side pushes the reflection member 2 in front of the sensor 33, so that the connection of the connector portion 14 is detected. However, any detecting means may be used in the present invention.

The connection portion of the connector portion 24 of the color single plate type electronic endoscope 20 is also constructed in the same manner as above, and the image pickup signals b, c, d and the connection detection signal h are output, but the projection 29 and The connection detection sensor 33 is attached at a position displaced from that of FIG. 3 (not shown).

FIG. 1 shows a light source device and a video processor 30.
2 shows the internal configuration of the device. Reference numerals 36 and 37 denote first and second light source lamps, and the illumination light emitted from each of the light source lamps 36 and 37 has a converging lens 38 disposed in front of each of them.
Light guide fiber bundles 16, 26 by 39
Converges near the incident end face of. Xenon lamps are used as the light source lamps 36 and 37, but it is also possible to use halogen lamps for one or both of them.

Light guide fiber bundles 16, 26
The amount of light flux incident on the movable diaphragms 40, 41 disposed between the light source lamps 36, 37 and the converging lenses 38, 39 is
Will be adjusted by 42 and 43 are light source lamps 36 and 3
It is a power supply for 7.

There are three colors of red (R), green (G), and blue (B) between the incident end surface of the light guide fiber bundle 16 of the frame-sequential type electronic endoscope 10 and the converging lens 38. A three-color rotary filter 44, in which the filters are arranged on the same circumference, is arranged and rotationally driven by a motor 45 at a constant speed. Therefore, the color of the illumination light emitted from the light guide fiber bundle 16 to the subject sequentially changes to three colors of red (R), green (G), and blue (B).

Reference numeral 46 denotes a filter rotation detector that detects the rotation speed of the three-color rotation filter 44 and outputs it as a pulse signal, and the driver 4 that supplies a drive current f to the motor 45.
The detection signal e is output to 7.

A synchronization signal is sent from the timing generator 50 to the driver 47, and the three-color rotation filter 44 rotates in synchronization with the charge accumulation / transfer timing of the solid-state image pickup device 13.

A circuit board 28 is built in the connector portion 24 of the color single plate type electronic endoscope 20. The circuit board 28 has a circuit for driving the solid-state image pickup device 23.
The signal sent from the solid-state image sensor 23 by a single line is R,
A circuit for dividing into G and B, an amplifier, a ROM in which setting data for each endoscope is written, and the like are mounted. From there, R and G are provided to the light source device / video processor 30 side. , B image pickup signals b, c, d are simultaneously output.

Although not shown, a circuit for driving the solid-state image pickup device 13, a driver circuit for a cable driver, and setting data for each endoscope are written in the frame sequential electronic endoscope 10. Built-in ROM etc.

Three image pickup signals R, G and B are input in parallel to an image pickup signal processing unit 51 which extracts a video signal from the image pickup signal and also performs gamma correction and the like, and two signals c and d of them are inputted. It is from the color single plate type electronic endoscope 20, and the other one is from the color single plate type electronic endoscope 20 and the frame sequential type electronic endoscope 10 by the changeover switch 53. Switched to.

The switching control is performed by the central processing unit (CP
U) is carried out by a control signal output from the control unit 54 incorporating the same. The control unit 54 includes a connection detection sensor 33,
The detection signals g and h from 34 are input.

The three analog video signals output from the image pickup signal processing unit 51 are sent to the analog-digital conversion circuit 57, respectively.
Depending on the element, the input range of analog voltage is, for example, 3V to 5
It is fixed like V and it is necessary to adapt the input signal to it.

Therefore, first, the DC voltage is reproduced in the clamp circuits 56 provided separately for the three systems, and the black level is fixed to a voltage suitable for input to the analog-digital conversion circuit 57.

FIG. 4 exemplifies the configuration of the clamp circuit 56, and first and second buffers 56 arranged at the signal input end and the signal output end in order to lower the output impedance.
A direct current power supply 56c for outputting a voltage for fixing the optical black level is connected between a and 56b via a switch 56d which is opened and closed by a clamp pulse given from a clamp pulse generator 63 described later. There is. The intermediate connection point A and the first buffer 56
A coupling capacitor 56e is provided between the output terminal of a and
Are connected by insertion.

When the video signal input to the clamp circuit 56 is viewed as a DC voltage, the optical black level constantly fluctuates depending on the amplitude of the video signal. Therefore, the switch 56d is closed by the optical black period, that is, the clamp pulse to forcibly set the potential at the intermediate connection point A to the predetermined voltage.

Returning to FIG. 1, after passing through the clamp circuit 56, the three systems of video signals converted into digital signals by the analog-digital conversion circuit 57 are passed through the signal path changeover switch 59 before being sent to the next memory 58. Go through.

The signal path changeover switch 59 is provided independently of each other in three systems, and in one state of the switching, the analog-digital conversion circuit 57 is provided in the memory 5 for each system.
Connect to 8.

Then, in the other state of switching as shown in FIG. 1, three analog-digital conversion circuits 57 are provided.
In order to distribute the frame-sequential video signal (quantized 8-bit parallel data) output from the conversion circuit through which the frame-sequential imaging signal passes among the three memories 58, i, j, and k in FIG. The on / off switching control as shown is performed by the timing generator 50.

Next, the video signal stored in the memory 58 for each of the three color signals of R, G, B is read by the three digital-analog conversion circuits 60 at the same timing. The operation of each memory 58 is controlled by the timing generator 50.

The video signal converted into an analog signal by the digital-analog conversion circuit 60 is sent to the video signal processing section 61, converted into, for example, a composite signal suitable for the television monitor 70 and output to the television monitor 70.

The switch 62 provided on the front panel of the light source device / video processor 30 is for image freeze (freezing). When the ON signal of the switch 62 is sent to the control unit 54, the control unit 54 The control of stopping the acquisition of new video data to the memory 58 and controlling so that only the data stored in the memory 58 at that time can be continuously output. As a result, a still image is displayed on the television monitor 70.

Reference numerals 63 (63a, 63b, 63c) are three clamp pulse generators for outputting clamp pulses having different cycles, respectively, and are timing generators 50.
Under control from.

As shown in FIG. 6, the first clamp pulse generator 63a includes a frame sequential electronic endoscope 10.
The clamp pulse having the same cycle as the black level cycle in the video signal (field sequential signal) is generated at the same timing as the black level.

The second clamp pulse generator 63a sets the clamp pulse having the same cycle as the black level cycle in the video signal (color single board signal) of the color single plate type electronic endoscope 20 to the black level. It occurs at the same timing.

The clamp pulse generated by the first clamp pulse generator 63a has a pulse width that is slightly shorter (nearly the same) than the black level period (length) in the frame sequential signal. The clamp pulse generated by the clamp pulse generator 63b has a pulse width slightly shorter than the period (length) of the black level in the color single plate signal.

Reference numeral 64 is a use pulse changeover switch which is switched under the control of the control unit 54, and which clamp pulse generator among the plurality of clamp pulse generators 63a, 63b and 63c is set as the pulse input terminal of the clamp circuit 56. It is for switching whether to connect.

Since the used pulse changeover switch 64 and the pulse input terminals of the three clamp circuits 56 are always connected in parallel, the clamp pulses of the three clamp circuits 56 always have the same cycle, pulse width and pulse height. Are input at the same timing.

The third clamp pulse generator 63c
Is the first and second clamp pulse generators 63a, 63
This is applicable to the case where a clamp pulse different from that of b is generated and a different type of electronic endoscope is used.

FIG. 7 is a flow chart showing the contents of a program executed in the control unit 54 to automatically switch the used pulse changeover switch 64 and the signal path changeover switch 59 in conjunction with each other, and S is a processing step. Indicates.

Here, first, the connection detection sensors 33, 34
Determines whether or not the connection of the endoscope is detected, and if the connection of the endoscope is not detected, the determination is repeated (S1).

When the endoscope connection is detected, it is determined whether or not it is the frame sequential electronic endoscope 10 (S2). When the connection of the frame-sequential type electronic endoscope 10 is detected, the color single plate type electronic endoscope 2 is further added.
It is determined whether or not the connection of 0 is detected, and if it is also detected that the color single-panel electronic endoscope 20 is connected, the process is restarted from the determination of S1 (S3).

When the connection of the color single plate type electronic endoscope 20 is not detected in S3, the pulse changeover switch used on the side of the first clamp pulse generator 63a for generating the clamp pulse suitable for the frame sequential video signal. 64 is switched, the clamp pulse is given to all the clamp circuits 56 (S4), and the signal path selector switch 59 is switched to a state suitable for the frame sequential video signal processing as shown in FIG. (S5).

When the connection of the frame-sequential type electronic endoscope 10 is not detected in S2, it is judged whether or not the connection of the color single plate type electronic endoscope 20 is detected, and the color single plate type electronic endoscope is detected. If it is not detected that the mirror 20 is connected, the process is restarted from the determination of S1 (S6).

When the connection of the color single plate type electronic endoscope 20 is detected in S6, the pulse to be used is switched to the second clamp pulse generator 63b side for generating the clamp pulse suitable for the color single plate type video signal. The switch 64 is switched to apply the clamp pulse to all the clamp circuits 56 (S7), and the signal path changeover switch 59 is switched to the parallel connection state suitable for the color single plate type video signal processing to finish (S8).

By doing so, a clamp pulse suitable for the image pickup system of the endoscope connected to the light source device / video processor 30 is applied to the clamp circuit 56, and an appropriate black level is fixed, and at the same time. The signal path changeover switch 59 is the light source device / video processor 30.
The state is switched to a state compatible with the imaging method of the endoscope connected to.

FIG. 8 shows the peripheral portion of the clamp circuit 56 according to the second embodiment of the present invention.
As shown in FIG. 6, one frame-sequential type first clamp circuit 56a and three color single-plate type second clamp circuits 56b are arranged in parallel.

A clamp pulse m adapted to a frame sequential video signal is input from the timing generator 50 to the first clamp circuit 56a, and a color single plate video signal is input to the three second clamp circuits 56b. A matching clamp pulse n is input from the timing generator 50.

Then, the output pulse from the timing generator 50 to the clamp circuit 56 is switched according to the control signal from the control section 54 in accordance with the image pickup method of the connected endoscope, and the image pickup method is adapted. The signal path is switched by the changeover switch 66 so that the clamp circuit 56 for switching is connected to the analog-digital conversion circuit 57.

[0062]

According to the present invention, it is used in a clamp circuit for fixing the black level in each video signal obtained from each of the frame sequential type and color single plate type image pickup means to a predetermined DC voltage. Since the clamp pulse corresponding to the imaging method of the endoscope is input, there is no problem of the clamp for fixing the black level, and the signal processing means compatible with both the frame sequential type and the color single plate type can be used. The device can be shared, and the device can be downsized at a lower cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a light source device and a video processor according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of the electronic endoscope apparatus according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a configuration of a connector section according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram showing an example of a clamp circuit according to the first embodiment of the present invention.

FIG. 5 is a time chart showing the switch opening / closing control according to the first embodiment of this invention.

FIG. 6 is a time chart diagram showing two clamp pulses according to the first embodiment of the present invention.

FIG. 7 is a control processing flowchart according to the first embodiment of this invention.

FIG. 8 is a block diagram showing a part of a signal processing unit according to a second embodiment of the present invention.

[Explanation of symbols]

 10 Frame Sequential Endoscope 13 Solid State Imaging Device 20 Color Single Plate Endoscope 23 Solid State Imaging Device 30 Light Source Device / Video Processor 56 Clamp Circuit 57 A / D Conversion Circuit 58 Memory 59 Signal Path Changeover Switch 60 D / A Conversion Circuit 61 Video signal processor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tsutomu Takizawa 2-36-9 Maeno-cho, Itabashi-ku, Tokyo Inside Asahi Kou Gakuin Co., Ltd. (72) Takayuki Enomoto 2-36-9 Maeno-cho, Itabashi-ku, Tokyo No. Asahi Kogaku Co., Ltd. (72) Inventor Hideo Sugimoto 2-36 Maenocho, Itabashi-ku, Tokyo No. 36-9 Asahi Kogaku Co., Ltd.

Claims (6)

[Claims] 1. A signal processing unit for performing signal processing for an endoscope having a frame-sequential color imaging unit, and a signal processing unit for performing an signal processing for an endoscope having a color single-plate color imaging unit. In an electronic endoscope apparatus that includes a signal processing unit and shares a part of the circuits of the both signal processing units, a black level in each video signal obtained from each of the image pickup units is fixed to a predetermined DC voltage. An electronic endoscope apparatus characterized in that a clamp circuit for performing the operation is provided in a common portion of the signal processing means, and a clamp pulse corresponding to an endoscope imaging method used is input to the clamp circuit. . 2. The clamp pulse is input to the clamp circuit at the same cycle as the cycle of the black level in the video signal obtained from the image pickup means of the endoscope used and at the same timing as the black level. The electronic endoscope apparatus according to claim 1. 3. The electronic endoscope apparatus according to claim 2, wherein the clamp pulse has a pulse width substantially the same as that of the black level period. 4. An endoscope type detecting means for detecting which one of the above-mentioned image pickup methods is used, and a response to a detection result by the endoscope type detecting means. 4. The electronic endoscope apparatus according to claim 1, 2 or 3, further comprising a clamp pulse selection unit that selects a clamp pulse to be input to the clamp circuit. 5. The clamp circuit is commonly used by the frame-sequential signal processing means and the color single-plate signal processing means, and the clamp circuit is used in accordance with the imaging system of the endoscope used. The electronic endoscope apparatus according to claim 1, 2, 3, or 4, wherein a clamp pulse supplied to the circuit is selected. 6. The clamp circuit is separately used for the frame-sequential signal processing means and the color single-plate signal processing means, and the clamp circuit is used in accordance with an imaging method of an endoscope used. A circuit is selected, claim 1, 2, 3 or 4.
The described electronic endoscope apparatus.