JP3132839B2 - Endoscope device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope device having a built-in solid-state image sensor.

[0002]

2. Description of the Related Art In recent years, with the development of semiconductor technology and high-density packaging technology, an endoscope device equipped with a video camera using a small solid-state imaging device and a small and lightweight solid-state imaging device have been utilized. An endoscope apparatus provided with this solid-state imaging device at the end of an endoscope insertion section is widely used.

In an endoscope apparatus provided with such a solid-state imaging device, a driving pulse is supplied from an external signal processing device to the solid-state imaging device provided at the end of the endoscope. When the element is driven, an imaging signal is obtained from the solid-state imaging element.

[0004] In this case, the driving pulse is supplied to the solid-state imaging device via a signal cable provided in the endoscope insertion portion. However, since this signal cable has reactance, the reactance varies depending on the length of the endoscope. The drive pulse is distorted by this effect, and the drive pulse is distorted by the influence of variations in the input capacitance and input impedance of the solid-state imaging device.

[0005] In order to prevent these problems, prior art endoscope apparatuses are disclosed in Japanese Patent Application Laid-Open Nos. 60-244161 and 61-241.
JP-A-92080, JP-A-62-135091, JP-A-62-121387, JP-A-63-2
No. 40828, Japanese Unexamined Patent Publication No. 63-283277, etc., a waveform correction circuit or the like is provided at a connector portion or a distal end portion of an endoscope device, and in addition to this, a waveform correction circuit is provided outside the endoscope device. A correction unit is provided for correcting variations among endoscopes connected to the signal processing device.

A conventional example of controlling a drive signal of a solid-state image sensor from such an image signal will be described with reference to the drawings.

FIGS. 14 and 15 relate to a conventional example, and FIG.
4 is a configuration diagram showing a configuration of a main part of an endoscope apparatus of a first conventional example, and FIG. 15 is a configuration of a main part of a second conventional endoscope apparatus which is a modified example of the first conventional example. FIG.

As shown in FIG. 14, the first conventional endoscope apparatus includes an endoscope 102 and a signal processing device 103.

In the signal processing device 103, a driving pulse for driving a solid-state image pickup device in the endoscope 102, for example, a CCD 107, for example, an anti-blooming pulse signal (hereinafter referred to as a ΦAB signal) is generated as follows. You.

That is, the synchronous signal generator (SSG) 10
4 from a reference clock signal generated in
An ON / OFF signal of the ΦAB signal is generated by a ΦAB waveform generator 104 including a PLD and a PLD. This O
The N / OFF signal is converted into a voltage having an amplitude necessary for driving the CCD by the driver circuit 100 at the next stage, and becomes a ΦAB signal.
5 to the endoscope 101.

On the other hand, a clamp diode D1 and a trimmer resistor VR1 are provided on the endoscope 101 side. The cathode side of the clamp diode D1 is the transmitted ΦA
The anode side is connected to the output terminal of the variable output three-terminal regulator 106 in the signal processing device 103 via the connection cable 109.

One end of the trimmer resistor VR1 is grounded, and the other end is connected to the variable output 3 via a connection cable 111.
It is connected to the voltage control terminal of the terminal regulator 106. A fixed resistor R1 is connected between the voltage control terminal and the input terminal of the variable output three-terminal regulator 106, and the output voltage of the variable output three-terminal regulator 106, that is, the clamp voltage of the ΦAB signal is fixed to the fixed resistor R1 and the trimmer. It is determined by the ratio with the resistance VR1.

The first conventional endoscope apparatus configured as described above can set an optimum offset voltage of the ΦAB signal for each endoscope 104 or each CCD 107, and can cause blooming, surface roughness, and the like. Can be suppressed.

Here, a variable output three-terminal regulator 106 for generating a clamp voltage of the ΦAB signal and a fixed resistor R1 are provided in the signal processing device 103.
01 can also be provided. In this case, the endoscope 101
Although the number of circuits on the side increases, the voltage level can be controlled with higher accuracy because the adjustment can be performed on the endoscope side including the variation of the variable output three-terminal regulator and the fixed resistance.

The endoscope apparatus of the second conventional example, which is a modified example of the first conventional example, differs from the first conventional example as shown in FIG. That is, there is no capacitor C1 and no clamp diode D1. That is, the ΦAB signal is transmitted by the DC of the endoscope 101,
The amplitude level and offset level of the B signal are determined by both the + and-power supply voltages of the driver circuit 100. The two power supply voltages, + and-, are connected to the trimmer resistors VR2, VR3 provided on the endoscope 101 side, the variable output three-terminal regulators 108, 110 on the signal processing device 103 side, and the fixed resistor R.
2, generated by R3.

[0016] Such a second conventional endoscope apparatus is as follows.
ΦA is determined by the trimmer resistors VR2 and VR3 on the endoscope 101 side.
Since the level of the upper end voltage and the lower end voltage of the waveform of the B signal can be changed, only the offset level can be adjusted.
The amplitude can be adjusted as compared with the conventional example, and a more optimal ΦAB signal can be obtained.

[0017]

However, in the first and second conventional endoscope devices, the adjustment of the amplitude level or the offset level of the ΦAB signal is manually performed by a trimmer resistor or the like. However, such adjustment requires a special adjustment device, and is performed at the time of factory shipment or maintenance, and is appropriately adjusted at the adjustment stage, but for an operator who operates these endoscopes, Since the amplitude level or offset level of the ΦAB signal is substantially fixed, it cannot be adjusted to the amplitude level or offset level of the ΦAB signal that matches the actual imaging signal when the endoscope apparatus is used.

Further, in the above-mentioned conventional endoscope apparatus, since the waveform correction circuit and the drive signal control circuit are provided at the distal end portion or the connector portion of the endoscope, the shape of the distal end portion or the connector portion becomes large. There is a problem that not only is it difficult to insert the insertion portion but also the patient suffers. Further, in the conventional example in which the correction unit for correcting the variation of each endoscope connected to the signal processing device is provided, the correction unit must be replaced every time the endoscope is replaced, which complicates the operation. In addition, since it is necessary to provide a correction unit suitable for each endoscope, the cost increases.

The present invention has been made in view of the above circumstances, and provides a drive signal control circuit capable of automatically adjusting the amplitude level and offset level of a drive signal of a solid-state image pickup device based on an image pickup signal. An object of the present invention is to provide an endoscope apparatus that can be downsized by being provided in a signal processing device of the apparatus.

[0020]

An endoscope apparatus according to the present invention comprises an endoscope provided with a solid-state image pickup device for picking up an image of a subject at an end of an insertion portion, and an image pickup output from the solid-state image pickup device. Screen dividing means for dividing a signal into a plurality of screen areas;
A luminance level detection unit that detects a luminance level of each of the plurality of screen regions divided by the screen division unit, and a luminance level of each of the plurality of screen regions detected by the luminance level detection unit and the solid-state imaging device. Comparing means for comparing conversion information preset according to a saturation level; control means for determining a value of an anti-blooming control signal for the plurality of screen regions based on a comparison result of the comparing means; Output means for outputting an anti-blooming control signal input to an anti-blooming control terminal of the solid-state imaging device in accordance with the value determined in (1), wherein the blooming is prevented.

The screen area is divided into a plurality of parts, and an anti-blooming control signal corresponding to each of the plurality of screen areas is generated to control blooming of the solid-state imaging device.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 4 relate to a first embodiment of the present invention, FIG. 1 is a block diagram showing a schematic configuration of an endoscope apparatus, FIG. 2 is an explanatory view for explaining the operation of the endoscope apparatus, FIG. 3 is an explanatory diagram illustrating the operation of a modified example of the start / stop control circuit, and FIG. 4 is a timing diagram illustrating the signal waveform of the modified example of the start / stop control circuit.

As shown in FIG. 1, the endoscope device 2 includes an endoscope 4 and a signal processing device 6 for processing an image signal from the endoscope.

The signal processing device 6 includes a preamplifier 14 disposed at the end of the endoscope 2, for example, a preamplifier 14 for amplifying an imaging signal from the CCD 8, and a signal amplified by the preamplifier 14. A signal processing circuit 16 for processing to generate an image signal, an A / D converter 20 for A / D converting the image signal generated by the signal processing circuit 16, and a characteristic signal level, for example, saturation, from the image signal And a characteristic image detection circuit 18 that generates a detection pulse when the rough level at the time of saturation is detected and the rough level at the time of saturation is detected.

Also, as a characteristic image processing means, an UP for counting detection pulses from the characteristic image detecting circuit 18 is provided.
A start / stop switch for controlling the transmission of the detection pulse to the counter 24 and the UP counter 24 by the switch SW1.
A stop control circuit 22, storage means 26 for storing the detected pulse count value of the UP counter 24 controlled by the start / stop control circuit 22, and a count value stored in the storage means 26
And a D / A converter 28 for performing A / A conversion.

The storage means 26 is composed of, for example, an SRAM (not shown) which is an IC memory.

The CCD driving circuit 1 is driven by a driving control signal from a control circuit 22 for controlling the driving of the CCD 8.
2 to the drive signal generated, for example, the ΦAB signal.
The multiplier 30 multiplies the count value subjected to the D / A conversion by the / A converter 28.

The output signal of the A / D converter 20 is
After being transmitted to an image signal processing unit (not shown) and subjected to signal processing, it can be displayed on a display monitor (not shown).

As shown in FIG. 2A, the endoscope apparatus 2 configured as described above has, for example, a saturated input signal a.
(See FIG. 2B-a) is compared with a reference voltage Vref1 set in advance by a power supply 36 by a comparator 34 which is a characteristic image detection circuit. If the reference voltage Vref1 is larger than Vref1, an H level is output (see FIG. B) -b),
The number of falling edges that change from H to L is counted by an integration counter 38, which is an UP counter at the next stage.

The count value is stored in the storage means 26 shown in FIG. 1, and after the stored count value is D / A converted, a drive signal generated by the CCD drive circuit 12, for example, a ΦAB signal is multiplied. I do. Then, the control circuit 22 controls Φ so that the count value becomes smaller.
The amplitude or offset level of the AB signal is varied, and the amplitude or offset level of the ΦAB signal is fixed at the smallest point.

Therefore, the endoscope apparatus 2 of the first embodiment
Can automatically adjust the amplitude level and offset level of the ΦAB signal of the CCD 8 based on the roughness level at the time of saturation of the imaging signal, and control the waveform correction and the drive signal by the signal processing device 6 of the endoscope device 2. Because we are going inside
The body of the endoscope 4 can be reduced in size.

As a modification of the start / stop control circuit 22, as shown in FIGS.
For example, a saturated input signal c (see FIG. 4C) is compared with a reference voltage Vref2 set in advance by a power supply 42 by a comparator 40, which is a characteristic image detection circuit, and outputs an H level when it is higher than Vref2. (See FIG. 4D), after being integrated by the integration circuit 44 (FIG.
-E), the sample-and-hold circuit 46 controls the timing of a clock from a synchronization signal generator (not shown) (FIG. 4).
(See -f.) The zara level at the time of saturation of one line is converted to a DC level. The power supply 50 is provided by the comparator 48 at the next stage.
Is compared with a preset reference voltage Vref3 (see FIG. 4G), and outputs an L signal at a level with a little saturation roughness (see FIG. 4H). Based on this, the operation of the UP counter 24 is controlled. Is what you do.

In the modified example of the start / stop control circuit configured as described above, the operation of the UP counter 24 can be automatically controlled without using a switch or the like.

FIGS. 5 and 6 relate to the second embodiment.
Is an explanatory diagram for explaining the operation of the endoscope apparatus, and FIG. 6 is a white band chart showing a white band chart for blooming detection.

The endoscope apparatus of the second embodiment differs from the first embodiment in that the characteristic image detecting circuit of the first embodiment is constituted by a circuit for detecting blooming, and the other configuration is the same as that of the first embodiment. I will explain only.

A white band chart 64 in which a white band 68 is drawn on a black portion 66 shown in FIG. 6A is picked up by an endoscope (not shown), and this picked-up image signal is converted to a saturated region detector 52 shown in FIG. By inputting, the area of the white belt 68 is detected and the switch 5
By turning on 8, the data is stored in the memory 54.

Next, a large amount of light is applied to the white band chart 64 to cause blooming 70 as shown in FIG. 6B in the image pickup signal. In this state, the switch 60 shown in FIG.
Is turned on, the difference processing circuit 56 compares it with the area of the white band 68 stored in the memory 54, and only the area of the blooming 70 is counted as the number of pulses by the integration counter 62 at the next stage. The amplitude or offset level of the ΦAB signal is varied so that the count value becomes smaller, and the amplitude or offset level of the ΦAB signal is fixed at the smallest value.

Other functions and effects are the same as those of the first embodiment.

FIG. 7 is an explanatory diagram for explaining the operation of the endoscope apparatus according to the third embodiment.

In the endoscope apparatus of the third embodiment, the characteristic image detecting circuit of the first embodiment is constituted by a circuit for detecting a rough level in darkness, and the other constitution is the same as that of the first embodiment. Only different parts will be described.

As shown in FIG. 7A, the input signal at the time of darkness is compared with a reference voltage Vref4 preset by the power supply 71 by the comparator 73 (see FIG. 7B-i).
If it is larger than ref4, an H level is output (FIG. 7).
(See (B) -j), the number of falling edges that change from H to L is counted by the integration counter 75. The amplitude or offset level of the ΦAB signal is varied so that the count value becomes smaller, and the amplitude or offset level of the ΦAB signal is fixed at the smallest value.

Other functions and effects are the same as those of the first embodiment.

FIGS. 8 to 11 relate to the fourth embodiment.
8 is a graph showing the relationship between the illuminance of the CCD plate surface and the CCD output level, FIG. 9 is a configuration diagram showing the configuration of a main part of the signal processing device, FIG.
FIG. 11 is a state diagram illustrating a saturated state of each divided image region.

Here, the Φ of the CCD used in the fourth embodiment is shown.
Table 1 shows the relationship between the amplitude of the AB signal and the characteristic image.

[0046]

[Table 1]

That is, as shown in FIG.
Depending on the amplitude of the AB signal, the CCD
The output level changes. That is, when the amplitude of the ΦAB signal of the CCD is large, the linear output level from the CCD becomes small, and the saturation level of each pixel varies, and
As a result, a roughness occurs at the time of saturation. Also, when the amplitude of the ΦAB signal is small, the linear output level from the CCD increases, that is, the dynamic range can be expanded, but blooming occurs.

Therefore, as shown in FIG. 9, the characteristic image processing means of the endoscope apparatus of the fourth embodiment comprises a screen dividing circuit 72 for dividing an input signal into a screen, and an area divided by the screen dividing circuit 72. A CPU 76 for comparing the luminance level for detecting each luminance level with conversion information set in advance in accordance with the saturation level of the solid-state imaging device, and controlling information for determining the amplitude of the ΦAB signal and the value of the offset voltage. .
The amplitude and offset voltage of the ΦAB signal generated by the CCD drive circuit 80 can be varied by a drive control signal from a control circuit 78 that controls the drive of a CCD (not shown in FIG. 9).

In the screen division, for example, as shown in FIG. 10, the image area 84 is divided into A, B, C, D, E, F, G,
It is divided into nine regions of H and I.

The other structure is the same as that of the first embodiment.

The operation of the thus configured endoscope apparatus will be described with reference to an image as shown in FIG.

In FIG. 11A showing an image of a living body forceps (not shown) at the time of insertion into a body cavity, blooming occurs from the coil sheath 86 of the body forceps when the driving condition of the ΦAB signal is not optimal. Here, when only the region D shown in FIG.
U76 is variably controlled so as to increase the amplitude of the ΦAB signal in order to prevent the occurrence of blooming.

As shown in FIG. 11B, in a cylindrical image, for example, the region E shown in FIG. 10 is considerably dark, and the region other than the region E is uniformly bright at a level that does not saturate. In this case, the dark noise in the area E is conspicuous, so that the CPU 76 variably controls the ΦAB signal to increase the amplitude in order to prevent the noise. When the region other than the region E has reached the saturation level, the CPU 76 variably controls the amplitude of the ΦAB signal to be small so that the saturation roughness is not conspicuous.

Further, in the image of the stomach wall as shown in FIG. 11C, for example, the regions A, B and D shown in FIG.
Is considerably dark, and the areas F, H, and I have a uniform brightness at a level where they are not affected, the CPU 76 increases the amplitude of the ΦAB signal in order to prevent the noise implied in the areas A, B, and D. Variable control. A, B, D
Is slightly bright and F, H, and I have reached the saturation level, the CPU 76 is controlled so that the saturation roughness is not conspicuous.
Is variably controlled so as to reduce the amplitude of the ΦAB signal.

As described above, in the endoscope apparatus of the fourth embodiment, since the amplitude of the ΦAB signal can be optimally changed according to the situation of the subject, the dynamic range of the CCD can be expanded.

Other functions and effects are the same as those of the first embodiment.

FIGS. 12 and 13 relate to the fifth embodiment.
FIG. 12 is a configuration diagram showing a configuration of a main part of the signal processing device.
3 is a perspective view showing the appearance of the signal processing device.

As shown in FIG. 5, the signal processing device of the endoscope apparatus according to the fifth embodiment has a saturated roughness detection circuit 92 for detecting a roughness level when an input signal from a CCD (not shown) is saturated.
And a blooming detection circuit 94 for detecting blooming
And a dark-state roughness detection circuit 96 for detecting a dark-level roughness level.
Using the levels output from the saturation detection circuit 92, blooming detection circuit 94, and dark detection circuit 96 as membership functions, a fuzzy operation is performed to vary at least one of the amplitude and the offset voltage of the ΦAB signal. And a fuzzy circuit 98. Other configurations are the same as those of the first embodiment.

The endoscope apparatus of the fifth embodiment thus configured performs a fuzzy operation on the characteristic signal of the input signal, so that the amplitude of the ΦAB signal can be optimally changed according to the situation of the subject. The dynamic range of the CCD can be expanded.

Other functions and effects are the same as those of the first embodiment.

As shown in FIG. 13, the signal processing device 6 receives power from an inlet 112 connected to a power connector 114 for supplying external power, passes through a transformer 116, and receives an internal circuit through a substrate power connector 124. 118 is driven. The inlet 112 grounds the signal processing device 6 via a screw 134. The signal is sent from the board connector 126 to the external connector 122. The internal circuit 118 is covered with a shield case 120 for suppressing noise of the circuit from being emitted to the outside. The board connector 126 is also substantially covered with a cover 115 having the same potential as the shield case 120 in order to minimize noise. Further, the external connector 122 is also made of a conductive material in order to suppress noise.
Screws 130, 131, 1 so as to be kept at the same potential as
32 and 133 are connected to a low impedance by a conductive plate 128.

Although the present embodiment has been described using the ΦAB signal as the CCD drive signal, the present embodiment is not limited to the ΦAB signal. For example, all CCD drive pulses such as a horizontal transfer pulse and a vertical transfer pulse are used. Can be similarly controlled.

[0063]

As described above, according to the present invention, the endoscope apparatus of the present invention includes an endoscope provided with a solid-state image pickup device for picking up a subject image at the distal end of an insertion section, and the endoscope. An endoscope apparatus comprising: a signal processing unit that performs signal processing on an imaging signal from the apparatus; wherein the signal processing device includes a driving signal generation unit that generates a driving signal that drives the solid-state imaging device; Detection means for detecting a characteristic phenomenon of the solid-state imaging device from the signal-processed image signal, and control means for controlling the driving signal based on the characteristic phenomenon of the solid-state imaging device detected by the detection means The control means for automatically adjusting and controlling the amplitude level and the offset level of the drive signal of the solid-state imaging device based on the characteristic phenomenon of the solid-state imaging device. By providing in the processing means, while implementing downsizing of the endoscope

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of an endoscope apparatus according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating an operation of the endoscope apparatus according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating an operation of a modification of the start / stop control circuit according to the first embodiment.

FIG. 4 is a timing chart illustrating signal waveforms of a modification of the start / stop control circuit according to the first embodiment.

FIG. 5 is an explanatory diagram illustrating an operation of the endoscope apparatus according to the second embodiment.

FIG. 6 is a white band chart diagram showing a white band chart for blooming detection according to the second embodiment.

FIG. 7 is an explanatory diagram illustrating an operation of the endoscope apparatus according to the third embodiment.

FIG. 8 is a graph showing the relationship between the illuminance of the CCD plate surface and the output level of the CCD according to the fourth embodiment.

FIG. 9 is a configuration diagram illustrating a configuration of a main part of a signal processing device according to a fourth embodiment.

FIG. 10 is a division state diagram illustrating an image division state according to a fourth embodiment.

FIG. 11 is a state diagram illustrating a saturated state of each divided image area according to the fourth embodiment.

FIG. 12 is a configuration diagram illustrating a configuration of a main part of a signal processing device according to a fifth embodiment;

FIG. 13 is a perspective view illustrating an appearance of a signal processing device according to a fifth embodiment.

FIG. 14 is a configuration diagram showing a configuration of a main part of a first conventional endoscope apparatus according to a conventional example.

FIG. 15 is a configuration diagram showing a configuration of a main part of an endoscope apparatus according to a second conventional example, which is a modification of the first conventional example according to the conventional example.

[Explanation of symbols]

 8 ... CCD 12 ... CCD drive circuit 16 ... Signal processing circuit 18 ... Characteristic image detection circuit 22 ... Start / stop control circuit 24 ... UP counter 34 ... Comparator 38 ... Integration counter

Continued on the front page (72) Inventor Masahiko Sasaki 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-Limpus Optical Industrial Co., Ltd. (72) Inventor Akinobu Uchikubo 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Within Optical Industry Co., Ltd. (72) Inventor Shinji Yamashita 2-43-2 Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. (72) Inventor Yuta Nakagawa 2-43-2, Hatagaya, Shibuya-ku, Tokyo O-limpus Optical Industry Co., Ltd. (56) References JP-A-59-69040 (JP, A) JP-A-63-232684 (JP, A)

Claims (1)

(57) [Claims] An endoscope provided with a solid-state imaging device for capturing an image of a subject at an end of an insertion portion; a screen dividing means for dividing an imaging signal output from the solid-state imaging device into a plurality of screen regions; Brightness level detecting means for detecting a brightness level of each of the plurality of screen areas divided by the screen dividing means; and a brightness level of each of the plurality of screen areas detected by the brightness level detecting means and saturation of the solid-state imaging device. On the level
Comparing means for comparing the conversion information set in advance in accordance, based on a comparison result of said comparing means, said plurality of screen areas
To determine the value of the anti-blooming control signal for
Control means, and the solid-state imaging device according to a value determined by the control means.
Anti-blooming control
An output means for outputting a rooming control signal , wherein blooming is prevented.