JPH0263428A - Electronic endoscope device - Google Patents

Abstract

PURPOSE:To reduce the number of parts, lower a cost, and miniaturize a control device by carrying out white balance adjustment with respect to a linear sequential signal. CONSTITUTION:The output of a color signal separating circuit 54 is made a linear sequential signal R/B and a white balance adjusting signal which is synchronized with this linear sequential signal R/B is generated by an adjusting signal generating circuit 57 to carry out white balance adjustment. By inputting the linear sequential signal R/B which is subjected to this white balance adjustment into one FM modulator 61, the number of modulators, insulating transformers, and demodulators can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a white balance adjustment circuit for an electronic endoscope having a solid-state image sensor at its tip.

[Prior Art and Problems to be Solved by the Invention] In recent years, there has been a rise in the number of cases in which internal organs, etc., can be diagnosed and examined by inserting a small-diameter insertion section into the body cavity.
f (scope or fiberscope) is widely used. Moreover, it is used not only for medical purposes but also for IQ purposes to observe and inspect objects inside pipes of boilers, machines, chemical plants, etc., or inside equipment.

Furthermore, electronic scopes using solid-state imaging devices such as charge-coupled devices (CODs) as layer imaging means are also used.

In the case of the electronic scope mentioned above, since it has an electric circuit at its tip, the secondary side circuit (AC input) is used to prevent electric shock.
A so-called patient circuit is constructed, which is completely isolated from the patient circuit, and the CCD, a driving circuit for the CCD, and a signal processing circuit for COD output are constructed as part of this patient circuit. Insulation between the secondary side circuit and the patient side circuit is generally achieved by a transformer or a photocoupler having a dielectric strength of 4 kV or more.

FIG. 8 shows a conventional example of insulating the secondary side circuit and the patient side circuit.

In FIG. 8, the electronic scope 1 is connected to a control device 4 composed of a patient side circuit 2 and a secondary side circuit 3. A driving clock or the like is applied from a COD driver 6 to a CCD 5 provided at the tip of the electronic scope 1, and a photoelectrically converted subject image is read out as an electrical signal.

This electrical signal is processed by a correlated double sampling circuit (hereinafter referred to as CD).
It is abbreviated as S circuit. )7. This CDS circuit 7
double sampling is performed to remove the 1/f and reset noise contained in the CCD output signal, and the noise component is removed to create a signal with a revised S/N ratio.This signal is branched, and one side is The luminance signal Y is separated and extracted through a low-pass filter (LPF) 8 and input to an FM modulator 9 and difference circuits 11 and 12 for generating color difference signals.The other signal is input to a color signal separation circuit 13. , a color signal R is generated from the color carrier wave generated by being superimposed on the photoelectric conversion output of the CCD 5.
, B are separated and extracted. These color signals R and B are supplied to gain control amplifiers 14 and 15, respectively, where white balance adjustment is performed.
The output level is controlled by the differential circuit 11.12
and color difference signals R-Y and B-Y are generated at the outputs of the difference circuits 11 and 12, respectively. This color difference signal R
-Y and B-Y are input to FM modulators 17 and 18 and modulated.

For each variable vA, the modulation output of 9, 17, and 18 is one isolation transformer.

20.21 becomes the patient side input, and the secondary side output is input to the FM demodulator 23, 24, and 25, respectively, and the luminance signal Y9 is input.
The color signals R-Y and B-Y are sent to the FM demodulator 23.24.25
19, the video signal processing circuit 26
It is entered into. The video signal processing circuit 26 receives the luminance signal Y2
The color signals R-Y and BY are processed and converted into a composite signal and three primary color signals R, G, and B, which are output to the monitor 27, and a subject image is displayed on the screen of the monitor 27.

As a conventional electronic endoscope as described above, the present applicant has proposed Japanese Patent Application No. 62-43578.

In FIG. 8, line sequential signals are synchronized by a synchronization circuit (not shown) connected to the next stage of the color separation circuit 13,
White balance adjustment is performed on the synchronized color signals R and B by gain adjustment amplifiers 14 and 15, respectively, and color difference signals R-Y and B-Y are generated from the color signals QR and B,
The color difference signals R-Y and B-Y are sent to an FM modulator 17.1.
8. This requires three FM modulators including one for the luminance signal, and three each of isolation transformers and FM demodulators, which is disadvantageous in terms of cost and increases the size of the control device. .

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide an electronic endoscope device with a white balance-like function that can reduce the number of parts, reduce costs, and downsize the control device. With the goal.

[Means for Solving the Problems] The electronic endoscope device of the present invention is an electronic endoscope that adjusts white balance by adjusting the gain of a video signal obtained from a solid-state imaging device. This device is equipped with a white balance adjustment means for controlling the gain in synchronization with the switching timing of the line sequential signal obtained by.

[Operations] In the present invention, a video signal as a line sequential signal is input to the white balance adjustment means. In the white balance adjustment means, gain control is performed in synchronization with the switching timing of the line sequential signal.

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

1 to 3 relate to the first fruit example of the present invention, and
The figure is a block diagram explaining the configuration of the electronic endoscope device.
The figure is an explanatory diagram of the white balance adjustment signal generation circuit.
The figure is an explanatory diagram of the operation of the white balance adjustment signal generation circuit.

As shown in FIG. 1, the electronic endoscope device 31 of the first embodiment includes an electronic scope 32 in which an image carrier is incorporated, and an electronic endoscope 32 that supplies illumination light to the electronic scope 32. It is composed of a control device 33 that processes signals. This control I device 33 is an insulating transformer 34.3.
Patient side circuit 37 and secondary side circuit 38 isolated by 5
It is composed of ℃.

The electronic scope 32 is formed with an elongated insertion portion 39 so as to be easily inserted into a body cavity, and an objective lens 41 is provided at the distal end side of the three insertion portions.

At the imaging position of this objective lens 41, a CCD 42 as a solid-state image carrier is provided. A color mosaic filter 45 is attached to the imaging surface of the CCD 42, which is a mosaic of color transmission filters that can transmit each color of light, for example, R (red), G (green), and B (blue).

Further, a light guide 43 for transmitting illumination light is inserted into the insertion section 39, and this light guide 43 transmits the illumination light supplied from the light source section 44 and emits it from the distal end surface. The illumination light illuminates a subject 49 through a light distribution lens 46.

The light source section 44 that supplies illumination light to the end surface on the proximal side of the light guide 43 includes a light source lamp 47 and a light source lamp 47.
A condensing lens 48 condenses and irradiates the illumination light 7 onto the end face of the light guide 43.

The object 49 & illuminated by the illumination light is color-separated by the color mosaic filter 45 and imaged by the objective lens 41 on the imaging surface of the CD 42. The image of the object 49 formed on the imaging surface of the CCD 42 is photoelectrically converted. C.O.
By applying a drive clock output from the D drive circuit 51, sequential transfer and reading are performed. The output signal of this CCD 42 is transmitted to the correlated double sampling circuit 5.
2 (hereinafter abbreviated as CDS circuit).

This CDS circuit 52 is connected to the 1/f included in the CCD output signal.
Then, double sampling is performed to remove reset noise, and a signal with the noise component removed and the S/N ratio changed is obtained. This signal is branched so that one side is input to a low-pass filter (hereinafter abbreviated as LPF) 53, and the other side is input to a color signal separation circuit 54. L
The PF 53 separates and extracts the luminance signal Y and inputs it to the EMa adjuster 56.

Further, the color signal separation circuit 54 inputs the input signal as shown in FIG. 3(a).
A color signal R and a color signal B as shown in the figure are outputted as a line sequential signal R/B that alternates every 11-1, and this line sequential signal R/B is inputted to five gain control amplifiers. The gain control amplifier 59 receives a line sequential signal R/R/ as shown in FIG. 3(b) generated by the white balance adjustment signal generation circuit 57.
A chopper-like adjustment signal synchronized with B is input. Third
The voltage ER in FIG. 5B coincides with the output timing of the color signal R, and the voltage Eb coincides with the output timing of the color signal. Line sequential signal R/B 4. t ffi pressure E
White balance adjustment is performed by controlling the respective signal levels of R and FB. The magnitude of the voltages ER and EB varies depending on the color temperature of the object 49, that is, the color temperature of the light source, and is adjusted appropriately.

Incidentally, FIG. 2 shows the white balance adjustment signal generation circuit 57.
A specific circuit is shown below. This white balance adjustment signal generation circuit 57 has a resistor R that can manually adjust the voltage ER, for example.
R, and a resistor R8 whose voltage EB can be adjusted manually, for example.
It is composed of a two-manufactured one-output switch 58 that switches the voltages Ell and EB in synchronization with the line sequential signal R/B, and outputs a white balance adjustment signal as shown in FIG. 3(b). It has become.

The line sequential signal R/B), which has undergone white balance adjustment by the gain control amplifier 59, is modulated by the tFM modulator 61.

The signal modulated by the FM modulator 56 is input to the FM demodulator 63 via the isolation transformer 34, demodulated, and input to the difference circuits 64, 65 and the video signal processing circuit 67. Further, the signal modulated by the FM modulator 61 is input to the synchronization circuit 69 via the insulating lance 35 and the FM demodulator 66. The isolation transformers 34 and 35 connect the patient side circuit 37 at the front stage and the secondary side circuit 38 at the rear stage.
It is designed to insulate the

The synchronization circuit 69 is composed of a 1H delay circuit and an analog switch, and receives the input line sequential signal R.
/B is synchronized and outputs color signals R and B. Color signal R
, 8 are the difference circuits 64 and 65, and the luminance signal Y produces color difference signals R-Y and B-Y, which are then output to the video signal processing circuit 67.
is input.

In the video signal processing circuit 67, the composite signal or
The signals are converted into primary color signals R, G, and B and output to the monitor 71 to display the image of the subject 49 on the screen.

In this embodiment, the output of the color signal separation circuit 54 is converted into a line sequential signal R.
/B, the adjustment signal generation circuit 57 generates a white balance adjustment signal synchronized with this line sequential signal R/B.
By inputting the line-sequential signal R/B, which has undergone white balance adjustment, to one FM modulator 61, the modulator, isolation transformer, and demodulator can be adjusted. It is possible to reduce the number and reduce the cost, and furthermore, the control device can be downsized.

4 and 5 relate to a second embodiment of the present invention, and FIG. 4 is a block diagram illustrating the configuration of an electronic intra'4JA chain device;
FIG. 5 is an explanatory diagram of the operation of the changeover switch.

In the first embodiment, white balance adjustment is manual, but
In this embodiment, this is automatically controlled. intransitive verb 6
11, the color difference signal R-Y, B-Y b< R-Y
= O, B - Y = O. However, in the configuration of the first embodiment, the color difference signals R-Y, B-Y
Since it is on the secondary side, it straddles an isolation circuit (insulation transformer), and the feedback circuit also requires an isolation circuit. Therefore, in this embodiment, the entire feedback circuit is provided within the patient-side circuit 37. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the explanation thereof will be omitted.

The output signal of the CDS circuit 52 is branched, and one side is connected to the LPF.
53 and becomes the at intensity signal Y, this luminance signal Y
is input to the FM modulator 56. The other signal is input to the color signal separation circuit 54 and becomes a line sequential signal R/B. This line sequential signal R/B is input to difference circuits 64 and 65.

The luminance signal Y output from the PF 53 is branched and input to the gain control amplifiers 76 and 77.

The gain control amplifier 76 focuses on the color signal B with respect to the line sequential signal R/B, and the color difference signal BY with the luminance signal Y is B-Y=
The gain is controlled by the white balance adjustment signal Va so that it becomes O. In this case, the signal f+R that appears alternately is also gain controlled, but this color signal R is an erroneous signal and is removed by the two-man power one-output switch 78 at the next stage. Similarly, the gain control amplifier 77 focuses on the color signal R and performs gain control using the white balance adjustment signal vb so that the color difference signal RY with the luminance signal Y becomes RY=O. In this case as well, the signal @B that appears alternately is gain controlled, but this color signal B is an erroneous signal and is removed by the two-man power one-output switch 78 at the next stage.

The luminance signals Y, Y whose gain has been controlled by the gain control amplifiers 76, 77 are input to the difference circuits 64, 65, which generate color difference signals R-Y, B-Y, and then the two-man power one-output switch 78 Enter. This two-manpower one-output switch 78 is switched by a child H/2 pulse, which is a pulse having the same timing as the switching timing of the line sequential signal R/B. Y,
By converting B-Y into line-sequential again, this line-sequential color difference signal R-,
-Y/8-Y is output to the FM tuner 61.

The line-sequential color difference signal R-Y/B-Y, which is the output signal of the two-manpower one-output switch 78, is branched and input to the one-manpower two-output switch 79. This one-manpower two-output switch 79 also has two manpower and one output.Similar to the switch 78, it is switched to the line-sequential color signal R/B by the fi1/2 pulse, which is the same timing pulse as the switching timing, and is switched to the line-sequential color difference signal R/B. Divide R-Y/B-Y. In Figure 5,
The input of the 1-manual 2-output switch 79 is the line-sequential color difference signal R-Y/8-Y as shown in (C) of the same figure, and the output is 1 as shown in (-8) and (b) of the same figure. The color difference signals R-Y and 8-Y are separated on a daily basis.

The color difference signals R-Y and B-Y are input to integrators 80 and 81, respectively, to obtain color difference average information for the entire screen (one field or one frame). The output of the integrator 80.81 is output to the comparator 82.83, and the reference potential yrer
compared to The value of this potential Vref is a target value for control, and is equal to the integral value when RY=O or BY=O. If the color difference output does not have a DC bias, the reference potential vref=OV may be used.

The outputs of the comparators 82.83 are sent to the up/down counters 85.83.
86. The count timing of the up/down counters 85 and 86 is normally performed at the speed of the vertical clock, and continues counting up or down until the color difference output reaches the target value.

The count value of this up/down counter 85.86 is D
The white balance adjustment signals QVa and Vb converted into analog signals by A/A converters 87 and 88 are inputted to the gain control amplifiers 76 and 77.

Here, unlike the conventional white balance circuit, 11-1
In order to integrate the signal every second, the value as an integral value decreases, but it is fed back in order to make the configuration of the single-power two-output switch 79, integrator 80.81, and comparator 82.83 function as a sample and hold circuit for the integral value. By simply increasing the loop gain slightly, it is possible to operate with the same precision as a conventional control circuit.

The signal modulated by the FM modulator 56 passes through the isolation transformer 34, is demodulated by the FM demodulator 63, and is input to the video signal processing circuit 67.

Further, the signal modulated by the FM modulator 61 is input to a synchronization circuit 69 via an isolation transformer 35 and an FM demodulator 66. The insulating transformers 34 and 35 are designed to insulate the patient side circuit 37 in the preceding stage from the secondary side circuit 38 in the succeeding stage.

The synchronization circuit 69 is composed of a 1H delay circuit and an analog switch, and receives the input line sequential signal R.
-Y/B -Y is the simultaneous color difference signal R-Y, B-Y
Output. Color difference signal R-Y.

B-Y is input to the video signal processing circuit 67.

In the video signal processing circuit 67, the composite signal or
The signals are converted into primary color signals R, G, and B and output to the monitor 71 to display the image of the subject 49 on the screen.

According to this embodiment, white balance adjustment can be automatically controlled by the patient-side circuit, and furthermore, the number of components of the isolation circuit can be reduced.

FIG. 6 is a block diagram showing the configuration of an electronic endoscope device according to a third embodiment of the present invention.

In this embodiment, in the second actual droplet example (color signal separation circuit 5
A difference circuit 91 is provided between the FM modulator 61 and the FM modulator 61 . This difference circuit 91 receives the line sequential signal R/B from the color signal separation circuit 51 and the luminance signal @Y from the LPF 53.
A brightness signal Y whose gain is adjusted by a gain control amplifier 92 is input. This difference circuit 91 generates a line sequential signal [-Y/B-Y, which is input to the FM modulator 61 and switch 79.

Moreover, the white balance adjustment signals Va, V of the second embodiment
b is input to the two-man power one-output switch 93. This switch 93 is switched by the H/2 pulse, and is configured to output Va at the output timing of the false color FR and output Vb at the timing of the color signal B. and,
The output of this switch 93 is input to the gain control amplifier 92 as a gain adjustment signal. Therefore, at the output timing of the false color QR, the gain control amplifier 92 adjusts the gain of the luminance signal Y using the white balance adjustment signal va so that the color difference signal RY=O, and
At the output timing of , the brightness signal Y is adjusted by the white balance adjustment signal vb so that the color difference signal B-Y=O.
Adjust the gain.

The other configurations are the same as in the second embodiment.

According to this embodiment, as in the second embodiment, the patient side circuit can automatically control white balance adjustment, and the second
The configuration is simpler than the embodiment.

In the first embodiment, the balance between the color difference signals R-Y and B-Y is achieved by adjusting the gain of the color signals R and B, and in the second embodiment, the balance is achieved by adjusting the gain of the luminance signal Y. Either can be applied as an embodiment. However, as shown in FIG. 6 1, this may be done by adjusting the gain of the luminance signal Y, or the gain control amplifier may be used as a chrominance signal separation circuit 54.
and the difference circuit 91, and the gain adjustment of the color signals R and B may be performed.

Other functions and effects are similar to those of the second embodiment.

Although FM modulation is performed in the first to third embodiments, the present invention is not limited to this, and AM modulation may also be used.

Further, although the above first to third embodiments have described a medical endoscope having an isolation circuit, the present invention is not limited to this, and as in the following fourth embodiment, a medical endoscope having an isolation circuit may be used. The present invention may be applied to industrial endoscopes or consumer video cameras.

FIG. 7 is a block diagram showing the configuration of an electronic endoscope device according to a fourth embodiment of the present invention.

Although this embodiment will be explained using an example of an industrial endoscope that does not have a light guide, a consumer video camera can also have a similar configuration.

In the endoscope of this embodiment, a camera head 95 is provided at the distal end of the insertion section. This camera head 95 has an objective lens 41 and a CCD 42, and a color mosaic filter 45 is pasted on the imaging surface of the CCD 42. As described above, this endoscope is not provided with an illumination optical system such as a light guide.

On the other hand, a control device 96 that performs signal processing for the camera head 95 is connected to a light source section 44, an ainlation transformer 34, 35, and an F.
The configuration is such that the M modulator 56.61 and the FM demodulator 63.66 are excluded.

The endoscope may be capable of attaching a lamp to its distal end if necessary, or may have an illumination optical system such as a light guide. In addition, the system (111 device 96 is
It may also have a light source section.

The other functions and effects of Structure 2 are the same as those of the second embodiment.

[Advantageous Effects of the Invention] As mentioned above, according to the present invention, white balance adjustment is performed for line-sequential signals, which reduces the number of parts, reduces costs, and downsizes the control device. Can be done.

[Brief explanation of the drawing]

Figures 1 to 3 relate to the first embodiment of the present invention.
The figure is a block diagram explaining the configuration of the electronic endoscope device.
The figure is an explanatory diagram of the white balance adjustment signal generation circuit.
The figure is a diagram explaining the operation of the white balance adjustment signal generation circuit.
4 and 5 relate to the second embodiment of the present invention, FIG. 4 is a block diagram explaining the configuration of the electronic endoscope device, FIG. 5 is an explanatory diagram of the operation of the changeover switch, and FIG. 6 is A block diagram showing the configuration of an electronic endoscope device according to a third embodiment of the present invention, FIG. 7 is a block diagram showing the configuration of an electronic endoscope device according to a fourth embodiment of the present invention, and FIG. FIG. 1 is a block diagram illustrating the configuration of a conventional example of a mirror device. 31...Electronic endoscope device 32...Electronic scope 33...Control device 57...White balance adjustment signal generation circuit 59...
・Gain control amplifier 71...monitor

Claims (1)

[Scope of Claims] An electronic endoscope that has a solid-state imaging device at the tip of an insertion section and adjusts white balance by adjusting the gain of a video signal obtained from the solid-state imaging device, comprising: What is claimed is: 1. An electronic endoscope apparatus comprising white balance adjustment means for controlling gain in synchronization with switching timing of a line-sequential signal obtained by the electronic endoscope apparatus.