JPH11346359A - Electronic endoscope device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic endoscope device that is applicable to multi- channel application by decreasing number of isolation devices even in the case of processing output signals from a solid-state image pickup element having pluralities of read channels. SOLUTION: Outputs of even numbered and odd numbered pixels from a CCD are given to by a multiplexer 34 via preamplifiers 29a, 29b or the like, where the signals are multiplexed into a one system signal, an output of the multiplexer 34 is fed to a secondary circuit 12 via a photocoupler 39 acting as an isolation device of a patient circuit 11. Then a sample-and-hold circuit 40 separates an output of the photocoupler 39 and the signal is processed for OB clamp processing or the like to correct dispersion or the like among channels and the signal is synthesized again by line memories 49a, 49b and the result is outputted. Thus, the number of isolation devices is reduced.

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 having an image pickup means and displaying an endoscope image on a monitor.

[0002]

2. Description of the Related Art In recent years, an insertion section is inserted into an observation site such as a body cavity, and illumination light is transmitted by illumination light transmission means such as a light guide fiber bundle and the like, and the observation site is irradiated from the tip of the insertion section. Endoscope devices for observing and treating a site are widely used.

One of the endoscope devices is an electronic endoscope device in which a charge-coupled device (abbreviated as CCD) is provided at the tip of an insertion portion, converts an image of an observation site into an electric signal, and displays the electric signal on a monitor. There is. With the recent increase in the number of pixels in CCDs, there is a technique for reading out video signals from the CCDs in a plurality of horizontal transfer paths in order to read out signals of all pixels at a standard TV signal rate.

[0004] The gain difference of the output amplifier of the CCD and the attenuation level of the signal due to the cable have individual differences among the endoscopes. Unless this level difference correction is performed, the output difference deteriorates the image quality on the monitor. appear.

Conventionally, filter processing has been performed to make this level difference difficult to see. However, the characteristics are deteriorated in a wide area of the frequency characteristics, and the resolution of the output image is reduced.

Accordingly, the present applicant has filed Japanese Patent Application No. 9/091056.
In this issue, we proposed an electronic endoscope system that corrects the output level difference between a plurality of horizontal transfer paths. This electronic endoscope device converts each output signal of a CCD having two horizontal transfer paths into a digital signal and independently controls the level of the digital signal based on the value of the digital signal, thereby providing a high-quality image. To be able to obtain.

[0007]

However, in the electronic endoscope device described in Japanese Patent Application No. 9-009156, when the number of CCD pixels further increases and the number of readout channels increases, the analog circuit in the patient circuit is increased. , Isolation transformers, analog circuits in the secondary circuit, A / D converters, etc. must be increased.

In particular, an increase in the number of isolation devices for transmitting signals between the patient circuit and the secondary circuit results in an increase in the board area. Further, an increase in the number of parts causes an increase in cost.

(Object of the Invention) The present invention has been made in view of the above points, and can reduce the number of isolation devices even when processing an output signal from a solid-state imaging device having a plurality of readout channels. It is an object of the present invention to provide an electronic endoscope apparatus which can be applied to multi-channel and the like.

[0010]

An electronic endoscope apparatus according to the present invention is provided with an endoscope provided with a solid-state image pickup device of a multi-channel readout type, and the endoscope is detachably connected to the endoscope. In an electronic endoscope apparatus having a signal processing circuit that performs signal processing of the video signal obtained in the above, a synthesizing unit that synthesizes a plurality of video signals read out from the solid-state imaging device in a patient circuit, and An isolation device that transmits the output of the combining device to the secondary circuit, a separating device that separates the output of the isolation device into signals for each of the plurality of channels, and performs signal processing on each of the outputs of the separating device to perform re-synthesis. By providing the video signal processing means, the number of isolation devices and circuit components can be reduced, and the invention can be applied to multi-channel and the like.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 to 8 relate to a first embodiment of the present invention, FIG. 1 shows a configuration of an electronic endoscope apparatus of the first embodiment, and FIG. FIG. 3 shows a configuration of a processing circuit, and FIG.
Shows the configuration of a sample-and-hold circuit, FIG. 5 shows how the photocoupler output is re-separated into two signals, FIG. 6 shows the configuration of an OB clamp circuit, and FIG. FIG. 8 shows an image part of the CCD which is sub-sampled by the image level averaging circuit.

As shown in FIG. 1, the electronic endoscope apparatus 1
An electronic endoscope 2 having a solid-state imaging device at its tip for observing the inside of a body cavity and the like, and a camera control unit (to be detachably connected to the electronic endoscope 2) for electrically processing an output signal from the solid-state imaging device ( The light source device 4 supplies R, G, and B plane-sequential illumination light for illuminating an observation site to a light guide 7 provided in the electronic endoscope 2, and a standard from the CCU 3. And a color monitor 5 for displaying a television signal of a format.

The electronic endoscope 2 has an elongated insertion portion 6 inserted into a body cavity or the like, and is detachably connected to the CCU 3 and the light source device 4. R supplied from the light source device 4,
The G and B plane-sequential illumination light is transmitted by a light guide 7 and illuminates a subject such as a diseased part from an illumination window at the distal end of the insertion section 6, and the subject image is reflected by the objective lens 8 attached to the observation window by the reflected light. It is connected to a charge-coupled device (abbreviated as CCD) 9 as a solid-state imaging device arranged at the image forming position. The subject image is converted into an electric signal by the CCD 9 so that signals of R, G, and B color components can be obtained.

On the patient circuit 11 side as a common circuit system with the CCD 9 inserted into a body cavity or the like in the CCU 3,
Synchronous signal generation circuit (hereinafter, SSG) for generating a synchronous signal
13. A crystal oscillator that generates a reference clock (hereinafter referred to as C
XO) 14, CCD drive circuit (hereinafter, DRV circuit)
The DRV circuit 15 outputs a CCD drive signal to the CCD 9 based on the output of the SSG 13.

The secondary circuit 12 as a circuit system insulated from the patient circuit 11 in the CCU 3 has an SSG 16,
A variable crystal oscillator (hereinafter, VCXO) 17 and a phase locked loop (hereinafter, PLL) 18 are provided, and the phase locked loop of the patient circuit 11 and the secondary circuit 12 is controlled by the PLL 18 for signal processing from the SSG 16. Various timing signals are generated.

A CCD 9 arranged at the tip of the electronic endoscope 2
Is a two-channel readout type having two horizontal transfer registers 9a and 9b, converts a subject image into an electric signal based on a CCD drive signal, and converts an odd-numbered pixel in the horizontal direction into one horizontal transfer register 9a. , And outputs the even-numbered pixel from the other horizontal transfer register 9b.

The CCD output signals of the two systems are subjected to electrical processing by the signal processing circuit 20 in the CCU 3, and then the output of the odd-numbered pixel horizontal transfer register and the even-numbered pixel horizontal transfer register are restored to the original order. Is output as a digital video signal in a state of being rearranged.

At the subsequent stage of the signal processing circuit 20, a gamma correction (γ correction) circuit 21, an outline emphasis circuit 22, an enlargement processing circuit 23, a synchronization memory 24, a moving image memory 25, a still image memory 26, a D / A converter 27 , 75Ω drive circuit 28 is output to the color monitor 5 as a standard format television signal.

The digital video signal output from the signal processing circuit 20 is subjected to gamma correction by a gamma correction circuit 21 and then subjected to enhancement of an outline component by an outline emphasis circuit 22 and displayed on a color monitor 5 by an enlargement processing circuit 23. The electronic enlargement process is performed at an enlargement ratio according to the size of the endoscope image.

The synchronization memory 24 includes an enlargement processing circuit 23
Are sequentially written in a time-series manner, and read out as R, G, B synchronized signals.

The output of the synchronization memory 24 is the moving image memory 2
5. The signal is sent to the D / A converter 27 through the still image memory 26 and is converted into an analog signal. The video signal converted to analog R, G, B signals by the D / A converter 27
After impedance matching is performed through the 5Ω driver circuit 28, the signal is sent to the color monitor 5.

Next, the configuration and operation of the signal processing circuit 20 in the electronic endoscope apparatus 1 according to the present embodiment will be described with reference to FIG.

Output video signals of two channels read from the CCD 9 (ie, even pixel output and odd pixel output)
Is amplified by the preamplifiers 29a and 29b on the patient circuit 11 side, converted into baseband signals by the CDS circuits 30a and 30b, and then returned by the low-pass filters 31a and 31b to return noise equal to or higher than the Nyquist frequency of A / D conversion. Is removed.

The outputs of the low-pass filters 31a and 31b are analog-clamped by the clamp circuits 32a and 32b, converted into digital signals by the A / D converters 33a and 33b, and are once synthesized by the multiplexer 34.

As shown in FIG. 3, the digital video signal of the odd pixel system (FIG. 3A) and the digital video signal of the even pixel system (FIG. 3B) are combined by the switching signal sent from the SSG 35 (FIG. 3). (FIG. 3 (C)).

The clock sent to the SSG 35 is an optical black period (O) of the odd pixel system CCD output signal.
The signal in the period B) and the output of the divide-by-2 circuit 38 of the VCXO 37 that has been phase-locked by the PLL circuit 36 are provided.

The signal output synthesized by the multiplexer 34 is output to a photocoupler 39 as an isolation device.
Thus, the signal is sent to the secondary circuit 12 insulated from the patient circuit 11 and sent to the sample-and-hold circuit 40 in the secondary circuit 12. Similarly, the output of the VCXO 37 of the patient circuit 11 is sent to the secondary circuit 12 by the photocoupler 41 and
VCXO 17 provided in secondary circuit 12 by L circuit 18
And phase synchronization is performed.

The output of the VCXO 17 is sent to the SSG 16 as a clock, and generates various timing signals in the secondary circuit 12. The sample and hold circuit 40 includes, for example, two flip-flops 40A and 40B as shown in FIG.
As shown in FIG. 5, the control signals CE1 and CE2 in the timing signal sent from the SSG 16 separate the video signal into an odd pixel series video signal and the even pixel series video signal.

The two separated digital signals are input to OB clamp circuits 42a and 42b. The OB clamp circuits 42a and 42b include an OB level averaging circuit 43, a data latch circuit 44, a subtractor 45, and a video level averaging circuit 46 as shown in FIG.

In the OB clamp circuits 42a and 42b, O
As shown in FIG. 7, the B level averaging circuit 43 uses 10 pixels (H) × 100 pixels (V) in the OB period of the digital signal.
Are sub-sampled to 4 pixels (H) × 64 pixels (V), and the level average value of the OB period for one screen is calculated.

Then, the data latch circuit 44 holds the calculated average OB level for each color based on the latch timing signal until the next frame-sequential signal of the same color component is input to the OB clamp circuit. 45, the OB level average value is subtracted from the video signal. In this way, by separating the digital video signal again and separately performing the OB clamp, it is possible to absorb variations in the analog clamp circuits 32a and 32b of the patient circuit 11.

The output of the subtractor 45 is output to the video level averaging circuit 4
8, as shown in FIG. 8, 100 pixels (H) × 100
Sub-sampling is performed on 64 pixels (H) × 64 pixels (V) of the pixels (V), and an average value for each screen is calculated for each color.

The average value of the video signal is sent to the CPU 48 of FIG. 1 in time series for each of R, G, and B colors. A white balance correction command is issued by a switch (not shown).
When the processing is performed on the PU 48, the CPU 48 averages the average values of the video signals of the two systems R, G, and B transmitted in time series, for example, every eight periods, and determines the ratio of these average values. Then, the white balance correction coefficient is calculated for each system. Further, the ratio of the G component of the average value of the video signals of the two systems is obtained, and a level difference correction coefficient for correcting the level difference between the channels is determined.

The outputs of the OB clamp circuits 42a and 42b are input to digital multipliers 47a and 47b, respectively.
From 48, a white balance correction coefficient and a multiplication coefficient based on the level difference correction coefficient are given. in this way,
The digital multipliers 47a and 47b perform the processing using the respective multiplication coefficients, thereby performing the level correction together with the white balance correction and absorbing the variation between the channels.

The outputs of the digital multipliers 47a and 47b are written to line memories 49a and 49b, respectively, and are read out alternately so that the odd-numbered horizontal transfer register outputs and the even-numbered horizontal transfer register outputs of the two systems of digital video signals are obtained. Are recombined.

As described above, the output signals of the two-channel readout type CCD 9 are combined, isolated, transmitted to the secondary circuit 12, separated, subjected to signal processing for each channel, and then re-combined. By performing the above, the number of isolation devices can be reduced, and required circuit components can be reduced due to the reduced number of systems compared to the case of a plurality of systems. Therefore, cost reduction is also possible.

After transmission to the secondary circuit 12, the signals are separated and subjected to signal processing for each channel, and adjustments are made so as to reduce variations in signals between channels. You can also get.

In this embodiment, the CCD 9 for two-channel reading is used. However, the present invention can be applied to a CCD having three or more reading channels. Therefore, it is suitable for multi-channel or high image quality.

(Second Embodiment) Next, a second embodiment of the present invention will be described. This embodiment is different from the first embodiment in that the configuration of the signal processing circuit 20 in FIG. 2 is changed as shown in FIG. 9, and the description of the operation of the common circuit is omitted.

As shown in FIG. 9, the two-channel output video signal read from the CCD 9 is amplified by the preamplifiers 29a and 29b on the patient circuit 11 side, and
After the signals are converted into baseband signals by Oa and 30b, they are combined by the analog switch 50.

The output of the analog switch 50 is filtered by a low-pass filter 31 to remove a frequency component equal to or higher than the Nyquist frequency of the A / D conversion. The signal is input to a photocoupler 39 as an isolation device.

As shown in FIG. 10, the odd pixel coefficient CD
S output signal and CDS output signal of even pixel system are SSG3
5 are combined by the switching signal sent by The processing after the photocoupler 39 is the same as in the first embodiment. As described above, this embodiment has almost the same effects as the first embodiment except that the number of parts can be reduced as compared with the first embodiment.

In the first and second embodiments, the signals of each channel are combined by combining means (specifically, the multiplexer 34) provided in the patient circuit 11 and transmitted by the isolation device. After the signals are separated into signals of each channel by the separation means on the secondary circuit side and the dispersion between channels and white balance adjustment are performed, re-synthesis is performed in the line memories 49a and 49b. Before combining by the combining means provided in the circuit 11, variations between channels and white balance adjustment are performed, and then combining is performed by the combining means and transmitted to the secondary circuit 12 side by an isolation device. Good (in this case, there is no need to further separate the signals into each channel on the secondary circuit 12 side).

For example, the OB clamp circuits 42a and 42 shown in FIG.
2b, the multiplying circuits 47a, 47b are connected to the A / D converters 33a,
Alternatively, the CPU 48 may be provided between the patient circuit 11 and the circuit 33b. In this way, the sample and hold circuit 40 for separating the output of the photocoupler 39 and the line memories 49a and 49b for synthesizing the separated signals can be directly input to the gamma correction circuit 21. This is 3
The present invention may be applied to a case of multi-channels equal to or more than channels.

(Third Embodiment) Next, when the CCD output is transmitted by an isolation transformer, the output in a period including a low-frequency signal component which may cause a DC level fluctuation is replaced by another signal. An electronic endoscope apparatus capable of obtaining a good image free from shading will be described.

As shown in FIG. 11, the electronic endoscope 51
Includes an endoscope 52 provided with a solid-state imaging device at the tip for observing the inside of a body cavity and the like, and a camera control unit 53 (hereinafter referred to as CCU) for electrically processing an output signal from the endoscope 52.
), A light source device (not shown) for supplying R, G, B plane-sequential illumination light for illuminating the observation site to a light guide (not shown) provided in the endoscope, and a standard format television from the CCU 53. And a color monitor (not shown) for displaying a version signal.

The endoscope 52 is detachably connected to the CCU 53, and converts an object image corresponding to the R, G, and B plane-sequential illuminating light emitted from the light source device to the observation site through the light guide into an electric signal. The conversion is performed to obtain signals of R, G, and B color components. Patient circuit 54 of CCU 53
A synchronizing signal generation circuit (hereinafter, referred to as SSG) 56, a crystal oscillator (hereinafter, referred to as CXO) 57, and a CCD drive circuit (hereinafter, referred to as DRV circuit) 58 are provided on the side. Output drive signal.

The secondary circuit 55 has an SSG 59, a variable crystal oscillator (hereinafter, VCXO) 60, and a phase locked loop (hereinafter, referred to as VCXO).
PLL 61 is provided, and the PLL 61 has a secondary circuit 55
The transmitted CCD output signal is input to the SSG 59, and various timing signals for signal processing are output from the SSG 59 in a state where the phase of the patient circuit 54 and the phase of the secondary circuit 55 are synchronized.

The CCD 62 disposed at the end of the endoscope 52
Converts the subject image into an electric signal based on the CCD drive signal and outputs the electric signal. This CCD output signal is amplified by an amplifier 63 in a patient circuit 54 in the CCU 53,
3 output from the analog switches 64a and 6
4b to the isolation transformer 65.

The CCD output signal is transmitted from the patient circuit 54 side to the secondary circuit 55 side by the isolation transformer 65, and the CDS circuit 67 located after the amplifier 66.
After being converted to the baseband by the A / D converter 6
At 8, it is converted into a digital video signal.

In the subsequent stage of the A / D converter 68, an outline emphasis circuit 69, an enlargement processing circuit 70, a synchronization memory 71, a gamma correction circuit 72, a moving image memory 73, a still image memory 74,
A D / A converter 75 and a 75Ω drive circuit 76 are provided, and the subject image is output to a color monitor as a standard format television signal.

The output of the amplifier 63 in the patient circuit 54 is connected to a PLL circuit 77 in the patient circuit 54, and a clock having the same frequency as the CCD drive frequency output from the VCXO 78 in the patient circuit 54, a CCD output signal and a phase synchronization signal. Is taken.

The clock from the VCXO 78 (FIG. 12)
(A) is input to the analog switches 64a and 64b after the amplitude is adjusted by the attenuator 79. FIG. 12B shows a clock signal input to the input terminal of the analog switch 64a. Analog switch 64a
The other input terminal receives the non-inverted output of the amplifier 63 as described above. This input waveform is shown in FIG.

The control terminals of the analog switches 64a and 64b are connected to the output terminal of the SSG 56 so that the period corresponding to the vertical transfer period of the CCD output signal can be replaced by the clock signal.
a and 64b are controlled.

The input and output terminal waveforms of the control terminal of the analog switch 64a are shown in FIG.
(E).

According to the above configuration, since the signal in the vertical transfer period of the CCD output signal is replaced by the clock signal equal to the CCD drive frequency, the vertical transfer period as shown in FIG. Can be eliminated.

Since a means for replacing the CCD output signal with the clock signal is provided in the CCU 53, the endoscope 52 is provided.
It is not necessary to add a circuit inside, and the endoscope 52 can be reduced in size and weight and a good endoscope image can be obtained.

(Modification of Third Embodiment) Next, a modification of the third embodiment will be described. This modification is an electronic endoscope apparatus having means for replacing a vertical transfer period of a CCD output signal inside an endoscope. With the third embodiment,
The configuration after the secondary circuit 55 is the same, and the description of the common parts is omitted.

In the modification shown in FIG. 13, the endoscope 52 and C
The patient circuit 54 of the CU 53 is shown, and will be described below with reference to FIG. On the patient circuit 54 side of the CCU 53,
Synchronization signal generation circuit (hereinafter, SSG) 56, crystal oscillator (hereinafter, CXO) 57, CCD drive circuit (hereinafter, D)
An RV circuit 58 is provided, and a CCD drive signal is output from the DRV circuit 58 based on the output of the SSG 56.

The CCD 62 disposed at the tip of the endoscope 52
Converts the subject image into an electric signal based on the CCD drive signal and outputs the electric signal. The CCD output signal is output from the C
The signal is input to an input terminal of an analog switch 64 provided near the CD. Further, the clock output from the CXO 57 in the CCU 53 and having the same frequency as the CCD drive frequency is input to the other input terminal of the analog switch 64 via the signal line in the endoscope 52 after the amplitude is adjusted by the attenuator 79. .

Similarly, a control signal indicating the vertical transfer period of the CCD output signal generated by the SSG 56 in the CCU 53 is also input to the control terminal of the analog switch 64 via a signal line in the endoscope 52. The signal line in the endoscope 52 usually has a length of about 2 to 3 m,
There is a time difference until the D drive signal is output from the DRV circuit 58 and the CCD output signal returns to the CCU 53.

That is, there is a phase difference between the clock output from the CXO 57 in the CCU 53 and the output from the amplifier 63. However, by arranging the analog switch 64 near the CCD 62 and replacing the signal at the tip, the clock and control signal are also delayed by the same amount as the transmission delay of the drive signal. No CCD output signal is output from the analog switch 64.

The CCD output signal whose vertical transfer period has been replaced by a clock signal is sent to the CCU 53, amplified by the amplifier 63, and then isolated.
To the amplifier 66 in the secondary circuit 55. The signal processing after the amplifier 66 is the same as that of the third embodiment in FIG. According to the above configuration, a good endoscope image can be obtained with a relatively simple configuration.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 14 shows the overall configuration of an electronic endoscope device 81 according to the fourth embodiment of the present invention. An objective lens 84 is disposed at the distal end of the insertion section 83 of the electronic endoscope 82, and a charge-coupled device (CCD) 85 as a solid-state imaging device is disposed at the subject image forming position. In addition, an illumination light guide 86 for irradiating the subject with illumination light is inserted into the insertion portion 83.

The illumination light guide 86 has a light source 87
A rotary RGB filter 90 that is driven to rotate at a constant speed by a motor 89 from a light source lamp 88 disposed therein.
R, G, and B plane-sequential illumination light that passes therethrough is emitted.

The video signal processing unit 91 is for performing image pickup in a frame sequential system, and is provided with a pre-processing circuit 92 and a CC.
The D drive circuit 93 is connected to the CCD 85 via a connector 94.
Is electrically connected to The control signal generation circuit 95 controls each circuit by applying the generated timing signal to each circuit unit. The CCD drive circuit 93 generates a drive signal for driving the CCD 85 based on a signal from the control signal generation circuit 95.

C driven by the CCD drive circuit 93
The video signal output from the CD 85 is input to a pre-processing circuit 92 and subjected to processing such as amplification and waveform shaping, and then converted into digital data by an A / D converter 96.

The video signal converted into digital data is subjected to video data enlargement / reduction processing by an enlargement / reduction circuit 97, and then, a synchronizing circuit 98 synchronizes frame-sequential RGB signals.

The synchronized video data is stored in the memory circuit 9
9, display control such as switching of a moving image / still image is performed, and then converted into an analog signal by the D / A converter 100 and
The video of the subject is reproduced on the color monitor 102 via the.

FIG. 15 shows a configuration of a memory circuit 99 according to the fourth embodiment. The RGB signals output from the synchronization circuit 98 are input to a moving image / still image switch 111 for switching between a moving image and a still image, and are also input to a color shift detecting circuit 112 for detecting a color shift.

The output of the color misregistration detection circuit 112 is input to a minimum value detection circuit 113 for judging the minimum color misregistration among the results of the color misregistration detection, and the minimum color misregistration detected by the minimum value detection circuit 113 is detected. Is a still image memory 115R, 1
15G and 115B.

The RG output from the synchronization circuit 98
The B signal is a frame delay memory 114R, 114 for compensating the processing time for the color shift detection by the color shift detection circuit 112 and the minimum color shift detection by the minimum value detection circuit 113.
G, 114B, and still image memories 115R, 115G,
115B.

The R signal output from the synchronizing circuit 98 becomes an R ′ signal delayed by a frame delay memory 116 for delaying one frame. The data is input to the still image memory 118 via the frame delay memory 117 for compensating the processing time of the minimum color shift detection.

The output signals of the still picture memories 118 and 115R are input to the moving picture / still picture changeover switch 111 via the changeover switch 119. The changeover switch 119 switches between the contacts a and b by an external instruction signal, for example, a color shift switching instruction signal.
5R and R still images with little color shift can be selected and displayed. Still image 115G,
The output signal of 115B is a moving image / still image switch 111
Is input to

Next, the operation of the present embodiment will be described. Usually, a moving image is displayed by the switch 111. When a freeze instruction signal is input from outside, the RGB video signal is separated into an R video signal R 'delayed by one frame for R and a normal R video signal. Of these, color shift detection is performed for the RGB signals.

As a method for detecting color misregistration, see Japanese Unexamined Patent Application Publication No.
19389 and JP-A-2-55485. The still image memory 11 stores the RGB still image data determined to be the minimum in the color misregistration detection.
5R, 115G, and 115B.

At this time, the R 'video signal for which no color shift is detected is also stored in the still picture memory 118. When it is determined that the R'GB video signal has the smallest color shift, the R'GB and RGB still images are operated externally to switch 11.
The smaller of the color misregistrations switched at step 9 is visually determined and displayed.

A method of synchronizing RGB video signals input to the display memory will be described. At the time of a normal moving image, as shown in FIG. 16, the input image data is composed of R, G, and B single-color frames (image data) for each period of a first vertical synchronization signal (hereinafter, referred to as VD1). Yes, the odd and even fields are time-divided.

This frame frequency is the same as NTSC, 60
Hz. The write chip select controller (not shown) selects the image data of Rn, Gn, and Bn in ascending order of the suffix n for each VD1 and cyclically repeats the image data to obtain the R, G, and B monochromatic plane-sequential. The image data is distributed to the R, G, and B memory banks, respectively, and is written to the frame memory.

Reading from the frame memory is performed by using a second vertical synchronizing signal (hereinafter referred to as VD2) immediately after writing is performed.
It is written. ) Is controlled by a read chip select controller (not shown) so as to read out the field data in synchronization with. This display field frequency is 50H
z.

At this time, a field that matches the field information of the video synchronization signal is read out for interlaced display. For example, in FIG. 16, after writing data of R2, even data of R2 is written in the next field, and R2 data is written in the next field.
Odd data is further added to the next field by the Ev of R2.
en data will be read.

The same operation is performed for the G and B data one field at a time. However, after writing R1 data, R1 reads R1 Even data in the next field and R1 Odd data in the next field. In the next field, R1 reads R2 Odd data instead of R1 Odd data. Data can be read. For this reason, in the example shown in the drawing, reading of fields from the memory is performed alternately in the order of 3 fields → 2 fields → 3 fields.

The effect of the present embodiment will be described.

There are various standards for color monitor display, such as NTSC, PAL, SECAM, etc., and the displayed field frequency is also different. However, if the video signal processing is also adjusted to the display frequency, it will be designed for each display standard, and the number of development steps will be enormous.

For this reason, the signal processing is performed at the same frame frequency, and is adjusted to the display frequency in a block capable of frequency conversion, such as after synchronization. If the frequency of the signal processing is the same as the frequency of the video display, there is no need to perform frequency conversion by synchronization, and each of the RGB data is updated every three fields.

However, in the example of FIG. 16, the signal processing frequency of VD1 is 60 Hz, and the video display frequency of VD2 is 50 Hz.
Therefore, the conversion is not sequentially performed well in time series. For example, the next combination of (R1, G1, B0) is (R
(1, G1, B1) is omitted, and (R2, G1, B1) is displayed.

If the combination (R1, G1, B1) is determined to have the smallest color shift by selectively displaying the data stored in the still image memory 118, the optimum color shift reduction is achieved. Images can be obtained as still images.

(Fifth Embodiment) Next, FIGS.
A fifth embodiment will be described with reference to FIG. This embodiment has the same configuration as the fourth embodiment shown in FIG.
However, the configuration of the memory circuit 99 is as shown in FIG.

The memory circuit 99 shown in FIG. 17 is different from the memory circuit 99 shown in FIG. 16 in that a color shift detecting circuit 121 for detecting a color shift from the R'GB signal is further provided. The output of the circuit 112 is input to the minimum value detection circuit 113.

In FIG. 16, the changeover switch 119 is switched by an external color shift switching instruction signal.
7 is switched by the output signal of the minimum value detection circuit 113. Other configurations are the same as those in FIG. 16, and the same components are denoted by the same reference numerals and description thereof will be omitted.

Next, the operation of the present embodiment will be described. Usually, a moving image is displayed by the switch 111. When a freeze instruction signal is input from outside, the RGB video signal is separated into an R 'video signal delayed by one frame for R and a normal R video signal. Detection of color misregistration is performed for each of the R'GB signal and the RGB signal.

Still image memories 118 and 115 which are determined to be the minimum among the two color misregistrations are detected.
G, 115B and 115R, 115G, 115B. Further, R′GB
And the still image of RGB is automatically selected by the switch 119 and displayed.

The effect of the present embodiment will be described.

In this embodiment, the minimum value detection circuit 11
3 automatically selects the still image memory storing the smaller of the color misregistration of the R'GB and RGB still images and displays it on the color monitor. This eliminates the need for an external operation for displaying the minimum value of the color misregistration. It should be noted that embodiments and the like configured by partially combining the above-described embodiments and the like also belong to the present invention.

[Supplementary Notes] An electronic endoscope apparatus having a signal processing circuit for detachably connecting an endoscope having a solid-state imaging device of a multi-channel readout type and performing signal processing of a video signal obtained by the solid-state imaging device. Synthesizing means arranged on a patient circuit for synthesizing video signals of a plurality of systems read from an image sensor, an isolation device for transmitting the output of the synthesizing means to a secondary circuit, and a plurality of outputs of the isolation device An electronic endoscope apparatus comprising: a separating unit that separates a video signal for each channel; and a video signal processing unit that re-combines the output of the separating unit after performing signal processing.

2. 2. The electronic endoscope apparatus according to claim 1, wherein the synthesizing unit synthesizes a plurality of video signals into a single video signal. 3. 2. The electronic endoscope apparatus according to claim 1, wherein the video signal processing unit has an adjustment unit that adjusts a variation between the video signals of a plurality of channels separated by the separation unit. 4. 4. The electronic endoscope apparatus according to claim 3, wherein the adjustment unit is a level adjustment unit that adjusts a variation in a video signal level among a plurality of video signals. 5. The electronic endoscope apparatus according to claim 4, wherein the level adjusting means is a white balance correction circuit.

6. An electronic endoscope having an endoscope provided with a multi-channel readout type solid-state imaging device, and a signal processing circuit to which the endoscope is detachably connected and which performs signal processing of a video signal obtained by the solid-state imaging device. In an endoscope device,
For each of the video signals of a plurality of channels read from the solid-state imaging device, an adjustment circuit provided in the patient circuit to reduce variations among the plurality of channels, and an adjustment circuit provided in the patient circuit and passing through the adjustment circuit An electronic endoscope apparatus comprising: a combining circuit that combines video signals of a plurality of channels; and an isolation device that transmits an output of the combining circuit to a secondary circuit.

(Background of Supplementary Note 6) (Prior Art, Problems to be Solved by Supplementary Note 6) Same as the column of the conventional technology and the problem to be solved by the invention in the specification. (Purpose of Supplementary Note 6) To provide an electronic endoscope apparatus capable of reducing the number of isolation devices and obtaining a high-quality image even when performing signal processing on an output signal from a solid-state imaging device having a plurality of readout channels. Appendix 6 for the purpose of
Was configured. (Effects of Supplementary Note 6) Even in the case of a solid-state imaging device having a plurality of readout channels, the number of isolation devices and circuit components of each channel system can be reduced, and the adjustment circuit can reduce variations among the plurality of channels. And high-quality images can be obtained.

7. In an electronic endoscope apparatus having an isolation transformer as a transmission unit for transmitting a video signal read from a solid-state imaging device from a patient circuit to a secondary circuit, a signal portion other than a video period of the video signal is replaced with another signal. An electronic endoscope apparatus comprising means for replacing a signal in a patient circuit.

(Background of Appendix 7) (Prior Art) In recent years, an insertion portion is inserted into an observation site such as a body cavity, and illumination light is transmitted by illumination light transmission means such as a light guide fiber bundle or the like, and the light is transmitted from the distal end of the insertion portion. 2. Description of the Related Art An endoscope apparatus that performs observation and treatment of an observation site by irradiating the observation site is widely used. One of the endoscope devices is disclosed in Japanese Patent Application No.
There is an electronic endoscope apparatus that has a CCD disposed at the distal end of an insertion section, converts an image of an observation site into an electric signal, and displays the electric signal on a color monitor, as proposed in Japanese Patent No. 091056. In this electronic endoscope apparatus, a patient circuit to which the endoscope is connected and a secondary circuit to which a color monitor and the like are connected are electrically separated by an isolation device to ensure electrical safety for the patient. doing.

A conventional electronic endoscope will be described with reference to FIG. An electronic endoscope device 51 'includes an endoscope 52' having a solid-state image sensor at its tip for observing the inside of a body cavity and the like, and a camera control unit (hereinafter, referred to as an electronic control unit) for electrically processing an output signal from the endoscope 52 '. A CCU 53 '), a light source device (not shown) for supplying R, G, B field-sequential illumination light for illuminating an observation site to a light guide (not shown) provided in the endoscope; And a color monitor (not shown) for displaying a standard format television signal.

The endoscope 52 ′ is detachably connected to the CCU 53 ′, and electrically converts a subject image corresponding to the R, G, B plane sequential illumination light emitted from the light source device to the observation site through the light guide. The signals are converted into signals to obtain signals of R, G, and B color components. A CCD drive circuit (hereinafter, DRV circuit) is provided on the patient circuit 54 side of the CCU 53 '.
58 are provided to output a CCD drive signal.

The CCD 6 arranged at the tip of the endoscope 52 '
Reference numeral 2 converts a subject image into an electric signal based on the CCD drive signal and outputs the electric signal. This CCD output signal is transmitted from the patient circuit 54 side to the secondary circuit 55 side by an isolation transformer 65 which is an isolation device.

On the secondary circuit 55 side, the CCD output signal is converted into a digital signal by the A / D converter 68 after the signal is converted into a baseband band by the CDS circuit 67 via the amplifier 66. At the subsequent stage of the A / D converter 68, an outline emphasis circuit 69, an enlargement processing circuit 70, a synchronization memory 71,
Gamma correction circuit 72, moving image memory 73, still image memory 7
4. A D / A converter 75 and a 75Ω drive circuit 76 are provided and output to a color monitor as a standard format television signal.

(Problem to be solved by Appendix 7) However, the frequency characteristics of the isolation transformer 65 used as the isolation device are such that the gain in the low frequency region and the high frequency region near DC is reduced.
When the CCD output signal as shown in FIG. 19A is transmitted by the isolation transformer 65, the DC level in the vertical transfer period including a low frequency component fluctuates as shown in FIG. 19B.

The subsequent video signal period (indicated by cross hatching) is similarly affected. The feedthrough period and the video signal period of the CCD output signal in which the DC level fluctuates due to the disturbance of the signal are different from the original waveforms, and the CDS circuit 67 samples and holds these periods.
The output has different signal levels at the left end and the right end in one horizontal period, which causes shading.

[0107] Appendix 7 is made in view of the above-described problem, and has as its object the purpose of transmitting an output during a period including a low-frequency signal component which may cause a DC level fluctuation when transmitting a CCD output through an isolation transformer. To provide an electronic endoscope device (a signal processing circuit thereof) capable of obtaining a good image free from shading by replacing the signal with another signal.

(Means and Actions for Solving the Problems)
In order to achieve the above objective, Appendix 7 states that 2
In an electronic endoscope apparatus having an isolation transformer as transmission means for transmitting a video signal read from a solid-state imaging device to a next circuit, means for replacing a signal portion other than a video period of the video signal with another signal In the patient circuit.

According to the above configuration, the signal output from the CCD is obtained by converting the signal in the vertical transfer period into another signal in the patient circuit.
For example, the clock is replaced with a clock having the same frequency as the CCD reading frequency. In this signal, a signal containing a relatively low frequency component in the vertical transfer period is replaced by a signal having almost the same frequency component as the video signal period. No deterioration occurs. This signal is transmitted to a secondary circuit via an isolation transformer, then subjected to signal processing, and output as a color monitor image.

8. Imaging means for imaging a subject sequentially illuminated with illumination light of a different wavelength range; motion detecting means for detecting the motion of the captured subject; and detecting a minimum amount of motion of the subject by an output of the motion detecting means. A color misregistration reducing apparatus comprising: a minimum value detection circuit for performing the operation; an output of the minimum value detection circuit; a still image storage unit for storing an image with a minimum amount of motion; and an image freeze instruction unit for outputting an image freeze instruction signal. A first image data obtained by a delay unit having a specific frame delay in at least one or more different wavelength ranges without passing through the delay unit, and a second image obtained by the delay unit through the delay unit First and second still image storage means for storing a still image based on the output of the minimum value detection circuit from the data, respectively, Color shift reducing apparatus, characterized by selectively displaying the smallest of the still image data of the motion amount of the still image storage unit above. 9. A delay unit having a specific frame delay, an output of the first motion detection unit based on image data obtained through the delay unit, and image data obtained without passing through the delay unit. Automatically detects the minimum value of the amount of motion from the output of the second motion detecting means, and stores the first or second image storing the still image with the smallest amount of motion.
4. The color misregistration reducing apparatus according to claim 3, wherein the still image data is displayed from the storage unit.

(Background of Supplementary Notes 8 and 9) (Technical field to which Supplementary Notes 7 and 8 belong) The present invention relates to a color misregistration reducing apparatus that performs a process of reducing color misregistration accompanying a frame sequential imaging method. (Conventional techniques for Supplementary Notes 8 and 9) In recent years, as a means for observing an affected part or the like in a living body, an electronic endoscope using a solid-state imaging device such as a CCD as a differential image means has been widely used. In addition, the electronic endoscope sequentially illuminates the subject with illumination light having different wavelengths such as red, green, and blue, and synthesizes a screen captured under illumination of each wavelength, that is, a component image. There is a plane-sequential electronic endoscope for obtaining a color image.

In such a frame sequential imaging apparatus, compared to a simultaneous imaging apparatus in which a mosaic color filter is arranged in front of the imaging surface of a solid-state imaging device using white light as illumination light, the solid-state imaging device for one wavelength region is used. There is an advantage that the number of imaging cells of the imaging element is large, and thus the resolution of the imaging screen is good. However, in the frame sequential method, in order to obtain an image of one color image, color images of components having different imaging times are combined. For this reason, if there is a relative movement between the moving subject or the imaging unit and the subject, the combined color image differs from the original color of the subject.

Hereinafter, such a defect, that is, a defect in color reproducibility caused by a difference in sampling time of each color information is referred to as a color shift. The color shift may be caused not only by the above-described movement but also by, for example, zooming. To solve the above problems,
The present applicant discloses in Japanese Patent Application Laid-Open No. Hei 4-212591 that a still image is not displayed on a color monitor at the same time that a freeze function is activated, but an image signal input within a specific time before and after a timing at which a freeze instruction is issued. For
We proposed a device that detects image blurring (color shift, etc.) and displays a signal with the least amount of detection as a still image on a color monitor or the like.

In this proposal, the frame frequency of the frame sequence and the frame frequency to be displayed on the color monitor (the field frequency in the case of interlace) are made to match each other.
There are several standards in the world such as AL. In the case where frame standard frame signal processing of the same frequency corresponds to these standards, the frame image is adjusted to the display frequency of the color monitor in a block that can change the frequency of the frame, such as a block for synchronizing the frame sequential signal.

At this time, in order to avoid unnatural movement of the image, the display frequency of the color monitor is set lower than the frequency of the signal processing. As a result, in the above case, the synthesis of the color images of the RGB components having different imaging times is partially omitted and displayed. When the freeze instruction is given, if the still image with the least amount of color misregistration detection is the partially omitted frame image, the best still image cannot be obtained.
Attentions 8 and 9 pay attention to this point, and in a video signal processing apparatus characterized by a display frequency such as a color monitor different from the frame sequential frame signal processing frequency, a signal with the least amount of detected color shift is regarded as a still image as a color monitor or the like. The present invention is characterized in that a device to be displayed is proposed.

(Means for Solving the Problems in Supplementary Notes 8 and 9 and Effects) a. Imaging means for imaging a subject sequentially illuminated with illumination light of a different wavelength range; motion detecting means for detecting the motion of the imaged subject; and detecting a minimum value of a motion amount of the subject based on an output of the motion detecting means. A color misregistration reducing apparatus comprising: a minimum value detection circuit for performing the operation; an output of the minimum value detection circuit; a still image storage unit for storing an image having a minimum amount of motion; A first image data obtained by a delay unit having a specific frame delay in at least one or more different wavelength ranges without passing through the delay unit, and a second image obtained by the delay unit through the delay unit First and second still image storage means for storing a still image based on the output of the minimum value detection circuit from the data, respectively, Color shift reducing apparatus, characterized by selectively displaying the smallest of the still image data of the motion amount of the still image storage unit above. (Operation of a) When a freeze instruction is given in the RGB signals synchronized by the synchronization means, a still image is displayed from the first storage means as an image having a minimum amount of motion by the motion detection means and the minimum value detection means. You. At this time, at the same time, a still image using image data of only the R of the RGB synchronization signal delayed by one frame is stored in the second storage means, and the amount of motion is stored in the first and second storage means by an external instruction. And selectively display still images with few images.

(Effect of a) RGB plane sequential video data that is not displayed as a moving image due to a difference in display frequency between a video signal processing frequency before synchronization and a color monitor after synchronization is minimized by an external operation. If it is determined that the value is a value, it can be selectively displayed as a still image from the second storage means. b. A delay unit having a specific frame delay, an output of the first motion detection unit based on image data obtained through the delay unit, and image data obtained without passing through the delay unit. Automatically detects the minimum value of the amount of motion from the output of the second motion detecting means, and stores the first or second image storing the still image with the smallest amount of motion.
A color misregistration reducing device for displaying still image data from the storage means.

(Operation of b) In the case where a freeze instruction is given from the outside in the RGB signals synchronized by the synchronization means, the first motion detection means and the first minimum value detection means make it possible to form an image having the minimum motion amount. Detected as a still image,
Is stored from the storage means. At this time, the image having the smallest amount of motion is detected as a still image by the second motion detecting means and the second minimum value detecting means using image data of only the R of the RGB synchronization signal delayed by one frame. 2
Is stored in the storage means. Then, the first minimum value detection means and the second minimum value detection means are compared, and a still image having a smaller amount of motion is selectively displayed from the first storage means or the second storage means. (Effect of b) The RGB plane sequential video data which is not displayed as a moving image due to the difference between the video signal processing frequency before the synchronization and the display frequency of the color monitor after the synchronization is different from the second.
If the motion amount detection circuit and the second minimum value detection circuit determine that the motion amount is smaller than the output of the first minimum value detection circuit, the motion amount is automatically displayed as a still image from the second storage means. .

[0119]

As described above, according to the present invention, an endoscope provided with a solid-state imaging device of a multi-channel readout type, and the endoscope is detachably connected to the endoscope. An electronic endoscope apparatus having a signal processing circuit for performing signal processing of a video signal obtained by combining a plurality of video signals read out from the solid-state imaging device in a patient circuit; Device for transmitting the signal to the secondary circuit, separation means for separating the output of the isolation device into signals for each of the plurality of channels, and video signal processing for performing signal processing on each of the outputs of the separation means and then re-synthesizing. Means, the number of isolation devices and circuit components can be reduced, the cost can be reduced, and the invention can be applied to increase the number of channels.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electronic endoscope apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a signal processing circuit.

FIG. 3 is an operation explanatory view showing a state in which signals of two systems are combined.

FIG. 4 is a circuit diagram illustrating a configuration of a sample and hold circuit.

FIG. 5 is an operation explanatory view showing a state where an output of a photocoupler is re-separated into two signals.

FIG. 6 is a block diagram illustrating a configuration of an OB clamp circuit.

FIG. 7 is a diagram showing an OB section of a CCD which is sub-sampled by an OB level averaging circuit.

FIG. 8 is a diagram showing an image portion of a CCD which is sub-sampled by an image level averaging circuit.

FIG. 9 is a block diagram illustrating a configuration of a signal processing circuit according to a second embodiment of the present invention.

FIG. 10 is an operation explanatory view showing a state where signals of two systems are combined.

FIG. 11 is a configuration diagram of an electronic endoscope apparatus according to a third embodiment of the present invention.

FIG. 12 is an operation explanatory view of the third embodiment.

FIG. 13 is a block diagram showing a configuration of a main part in a modification of the third embodiment.

FIG. 14 is a configuration diagram of an electronic endoscope apparatus according to a fourth embodiment of the present invention.

FIG. 15 is a block diagram illustrating a configuration of a memory circuit in FIG. 14;

FIG. 16 is an operation explanatory view of the fourth embodiment.

FIG. 17 is a block diagram showing a configuration of a memory circuit according to a fifth embodiment of the present invention.

FIG. 18 is a configuration diagram of a conventional electronic endoscope device.

FIG. 19 is an operation explanatory view of FIG. 18;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope device 2 ... Electronic endoscope 3 ... CCU 4 ... Light source device 5 ... Color monitor 6 ... Insertion part 7 ... Light guide 8 ... Objective lens 9 ... CCD 9a, 9b ... Horizontal transfer register 11 ... Patient circuit 12 Secondary circuit 13, 16 SSG 14 CXO 15 DRV circuit 17 VCXO 18 PLL 21 Gamma correction circuit 24 Synchronization memory 29a, 29b Preamplifier 30a, 30b CDS circuit 32a, 32b Clamp circuit 33a, 33b A / D converter 34 Multiplexer 39 Photocoupler 40 Sample hold circuit 42a, 42b OB clamp circuit 49a, 49b Line memory

Claims (1)

[Claims] 1. An endoscope having a solid-state imaging device of a multi-channel readout type, wherein the endoscope is detachably connected,
A signal processing circuit that performs signal processing of a video signal obtained by the solid-state imaging device, wherein the signal processing circuit is arranged on a patient circuit that combines a plurality of video signals read from the solid-state imaging device. A separating device that transmits an output of the combining device to a secondary circuit, a separating device that separates an output of the isolation device into video signals for a plurality of channels, and an output of the separating device. An electronic endoscope apparatus, comprising: video signal processing means for performing re-synthesis after performing signal processing.