JPH0284929A - Electronic endoscope device - Google Patents

Abstract

PURPOSE:To execute chrominance demodulation without fail and to improve picture quality by defining the output signal of an image pickup means as a chrominance signal to be sequenced by a chrominance signal generating means, executing isolation processing for this chrominance signal and after that, transmitting the chrominance signal to a video signal processing means. CONSTITUTION:Sequential color difference signals R-Y and B-Y to be outputted from a high luminance coloring prevention circuit 39 are inputted to an isolation circuit 11a and transmitted from a patient circuit to a secondary circuit. Then, the signals are inputted to a post-process circuit 12. A luminance signal Y to be separated by an LPF34 is inputted to an isolation circuit 11b and after that, inputted to the post- process circuit 12. Then, prescribed signal processing is executed for the luminance signal together with the sequential color difference signal. On the other hand, when a timing pulse is generated from a pulse generator 31 in the patient circuit side, the timing pulse is sent to the secondary circuit side by a pulse isolation circuit 42 and inputted to a pulse generator 43. The sequential color difference signal to be inputted to the post-process circuit 12 is made coincident by the timing pulse from the pulse generator 43 and various signal processing is executed together with the luminance signal Y. Then, the sequential color difference signal is converted to the video signal and outputted to a color monitor 13 and the picture of a subject 5 is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic endoscope apparatus having an isolation means.

[Prior art and problems to be solved by the invention] In recent years, it has become possible to observe internal organs in a body cavity by inserting an elongated insertion section into a body cavity, and to insert a treatment instrument inserted into a treatment instrument channel as necessary. Endoscopes, which can be used to perform various therapeutic procedures, are widely used.

In addition, various electronic endoscopes have been proposed in which a solid-state imaging device (hereinafter abbreviated as CCD) such as a charge-coupled device is installed as an imaging means at the distal end of the insertion section, and image information is extracted as a photoelectrically converted electrical signal. has been done.

The above-mentioned electronic endoscope has an electric circuit at its tip, so as a measure to prevent electric shock, it forms a so-called patient circuit that is completely isolated from the secondary circuit (AC input). As part of the CCD, C
It constitutes a CD drive circuit and a COD output preprocessing circuit. Insulation between the patient circuit and the secondary circuit is generally achieved by a transformer or photocoupler having a dielectric strength of 4 kV or more. An endoscope apparatus having this isolation circuit has been proposed in Japanese Patent Application No. 62-43578 by the present applicant.

The configuration of an electric preparatory microscope device having the above-mentioned isolation circuit is shown in FIGS. 10 and 11.

In FIG. 10, illumination light output from a light source device (not shown) is transmitted through a light guide 2 inserted through an electronic scope 1.
The light is guided to the distal end 3 and irradiated onto the subject 5 via the light distribution lens system 4. An image of the object 5 created by this illumination light is formed on the CCD 7 by the imaging optical system 6. The signal photoelectrically converted by this CCD 7 is sent through a signal transmission cable 8 to a preprocessing circuit 10 that constitutes a video signal processing circuit 9, is preprocessed by this preprocessing circuit 10, and is connected to a patient circuit by an isolation circuit 11. It is insulated from the next circuit, undergoes predetermined processing by the post-processing circuit 12, and is output as a video signal, such as an NTSC or RGB three primary color signal, to the color monitor 1.
It is displayed as an image by 3rd grade.

Here, the configuration of the preprocess circuit 10 is shown in FIG.

The output of the CCD 7 is amplified by an amplifier 14 to compensate for the attenuation valve for attenuation and matching in cable transmission, and the noise contained in the output of the CCD 7 is reduced by a noise reduction circuit 15 such as correlated double sampling, and luminance color reproduction is performed. The circuit 16 outputs a luminance signal Y and a color difference signal RY,
B-Y is generated. These luminance signal Y and color difference signals RY and B-Y are input to the isolation circuit 11 and sent from the patient circuit to the secondary circuit.

By the way, in the above conventional example, three transmission lines are required to pass the brightness signal Y and the color difference signals R-Y, B-Y through the isolation circuit, but the isolation circuit 11 stabilizes the high frequency signal. Since it is expensive, providing each of the three systems will increase the cost. Therefore, in order to reduce costs, it is necessary to reduce the number of transmission lines.

It is also possible to perform isolation before the luminance and color reproduction circuit 16, but if isolation is performed here, high-frequency CCD 7 drive pulses, color demodulation pulses, and correlation between the patient circuit and the secondary circuit can be considered. The pulses for double sampling must be transmitted through an isolation circuit. However, a transformer used as an isolation circuit attenuates high frequency components, making it impossible to perform reliable sampling. Here, if the phase of the color demodulation pulse shifts, the color signal level decreases, and if the phase of the correlated double sampling pulse shifts, the S/N of the video signal deteriorates.

Therefore, when high-frequency pulses are passed through an isolation circuit for the above-mentioned reasons, image quality may deteriorate due to variations in delay characteristics and temperature changes.

Note that Japanese Patent Application No. 144515/1988 proposed by the present applicant discloses a color difference signal output means for alternately extracting first and second color difference signals.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an electronic endoscope device that can reduce the number of signal lines and parts, is low cost, and does not deteriorate image quality.

[Means for Solving the Problems] The electronic endoscope device of the present invention has two components: a color signal generation means for generating sequential color signals from electrical signals in a patient circuit including an imaging means, and a video signal processing means. and isolation means for subjecting the color signal to isolation processing and transmitting it to the next circuit system.

[Operation] In the present invention, the output signal of the imaging means is a color signal that is sequentially frozen by the color signal generation means. This color signal is subjected to isolation processing by the isolation means and then transmitted to the video signal processing means.

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

1 to 3 show the first embodiment of the present invention, and the first embodiment
The figure is a block diagram explaining the configuration of the electronic endoscope device.
The figure is an explanatory diagram of the configuration of the color filter array, and FIG. 3 is a diagram of the entire configuration of the electronic endoscope device.

It should be noted that the reference numerals in this embodiment are the same as those in the conventional example for the same functions.

As shown in FIG. 1, the electronic endoscope device 21 of this embodiment includes an electronic scope 1 and a camera control unit (hereinafter referred to as CCU) to which the electronic scope 1 is connected and which performs signal processing.
It is abbreviated as. ) 22, a light source device @23 that supplies illumination light to the electronic scope 1, and a color monitor 13 that displays video signals output from the CCU 22.

The electronic scope 1 includes an elongated insertion section 24, a large-diameter operation section 17 connected to the rear end of the insertion section 24, and a light guide and signal section extending from the side of the operation section 17. A cable 18 is provided.

A hard tip portion 3 is provided on the tip side of the insertion portion 24, and a bending portion 1 adjacent to the tip portion 3 is capable of bending toward the rear side.
9 is provided. Furthermore, a flexible soft part 2 (l) is connected to the rear of this curved part 19.
9 can be bent vertically/horizontally by operating a bending operation knob 25 provided on the operating section 17.

A light guide and signal connector 46 is provided at the rear end of the light guide and signal cable 18, and is connected to the light source device 23 and CCLJ 22 at the same time.
It is now possible to This light source device 23 and CCU 22
is a signal cable 48 with connectors 47 on both ends.
connected by. Furthermore, CC[J22 is connected to the color monitor 13 by a signal cable 49.

The electronic scope 1 is formed with an elongated insertion section 24 so as to be easily inserted into a body cavity, and an imaging optical system 6 is provided on the distal end side of the insertion section 24. At the imaging position of this imaging optical system 6, a CCD 7 is provided as a Jti imaging means. The imaging surface of this CCD 7 is yellow (Ye; transmits R and G), magenta (Ma: R
and B are transmitted. ), cyan (Cy: transmits B and G) color filter array 26 is attached.

Furthermore, a light guide 2 formed of a fiber bundle for transmitting illumination light is inserted into the insertion portion 24, and this light guide 2 transmits the illumination light supplied from the light source device 23, and has an output end face. The light is emitted from the light distribution lens system 4 and illuminates the subject 5.

The light source device 23 that supplies illumination light to the proximal end surface of the light guide 2 is composed of a light source lamp 27 and a condensing lens 28 that condenses and irradiates the illumination light from the light source lamp 27 onto the end surface of the light guide 2. ing.

The image of the object 5 illuminated by the illumination light is color-separated by the color filter array 26 and is imaged on the imaging surface of the CCD 7 by the imaging optical system 6. The object 5 image formed on the imaging surface of the CCD 7 is photoelectrically converted and sent to the drive pulse generator 2.
By applying a driving pulse from 9, it is read out as an electrical signal. Note that the drive pulse generator 29 receives a pulse signal from the pulse generator 31 and generates a drive pulse. The electric signal containing the read video information is input to a noise reduction circuit 15 such as a correlated double sampling circuit in the CCLJ 22 via a signal transmission cable 8 inserted through the insertion section 24.

The noise reduction circuit 15 performs double sampling using the sampling pulse output from the pulse generator 31 to produce a signal with improved S/N. This signal is branched and
One of the signals is set to an optimum γ value by the γ correction circuit 32 and inputted to the luminance color separation circuit 33 as a color signal reproducing means. This input signal has a color filter 26.
In the case of the output of CD7, the signal form is a luminance signal Y and a color signal multiplexed. In the luminance color separation circuit 33, the luminance signal Y is separated by a low pass filter (hereinafter abbreviated as LPF) 34 and output. Further, the color components of the signal input to the luminance color separation circuit 33 are simultaneously separated by a band pass filter (hereinafter abbreviated as BPF) 36 and input to a detector 37, and the color demodulated signal is output from the pulse generator 31. III by pulse.

When the color filter array 26 is arranged as shown in FIG. 2, the color signals output from the detector 37 are R-Y,
This becomes a signal equivalent to a signal in which a color difference signal such as B-Y is serialized every horizontal line period.

That is, in FIG. 2, two lines are read out simultaneously for one line, and in odd fields, the n and n+1 rows in FIG. 2 are read out simultaneously, and the upper and lower pixel information is mixed and output, Now, n+1 in Figure 2
and (n+2) rows are simultaneously read out, and the upper and lower pixels are mixed and output. If we explain in odd field, n and n+
In a mixed line, the signal obtained by adding each pixel, that is, Mg + Cy + Ye = R + 8 - 1 - B + G + G + R + G - 2 R + 3 G + 2 B, is equivalently the luminance signal Y, and the signal obtained by subtracting the adjacent pixels, that is, ( MO+CV)-(G+Ye)-(R+B+B+G)-(G+R+G)28-G equivalently becomes the color difference signal B-Y.

Furthermore, in the line where n+2 and n+3 rows are mixed, the signal obtained by adding each pixel is Mg+CV+G+Ye -R+ B + B + G + G + R+ G=
2R+3G+2B, which equivalently becomes the luminance signal Y in the same way as the lines mixed with the n and n+i lines above, and the signal obtained by subtracting the adjacent pixels, that is, (Ma+Ye)-(G+Cy) = (R+B+R+G)-(G+B+G )=2R-G equivalently becomes the color difference signal R-Y.

Note that the luminance/color separation circuit 33 may use a sampling circuit.

The color difference signals R-Y, [
3-Y are sequentially arranged in a white balance circuit 38, and white balance adjustment is performed on each of them. Color difference signals R-Y and B- output from this white balance circuit 38
Y is sent to the high brightness coloring prevention circuit 39. This high-brightness coloring prevention circuit 39 has a color filter array 26 attached to the CCD 7, and γ correction is performed to prevent the white balance from being disrupted and coloring to occur because the brightness levels at which pixels are saturated for each color are different. The color signal component is removed by the LPF 41 from the output signal of the noise reduction circuit 15 that has not been used, and the color difference signal level of the portion where the level has become too large and the white balance of the color difference signal has collapsed is determined by the signal from which the color signal component has been removed. Attenuate. Sequential color difference signal RY/B output from this high brightness coloring prevention circuit 39
-Y is an isolation circuit 11 such as a transformer.
a, is transmitted from the patient circuit to the secondary circuit, and is input to the post-processing circuit 12 as a video signal processing means. In addition, the luminance signal Y separated by the LPF 34 is input to the isolation path 11b and then input to the post-processing circuit 12, where it is sequentially input to the colorimetric difference signals @R-Y, 8-Y.
At the same time, predetermined signal processing is performed. Isolation circuit 11a.

11b is designed to insulate the patient circuit at the front stage from the secondary circuit side at the rear stage.

On the other hand, a timing pulse for the secondary circuit is generated from the pulse generator 31 on the patient circuit side, which is also sent to the secondary circuit side by the pulse isolator circuit 42, and is inputted to the secondary circuit side pulse generator 43. Synchronizes various timing pulses on the patient circuit side and the secondary circuit side.

The sequential color difference signals R-Y/B-Y inputted to the post-processing circuit 12 are synchronized by a synchronization circuit (not shown) using timing pulses from a pulse generator 43.
Various signal processing is performed together with Tli degree signal @Y, for example, N
The signal is converted into a video signal such as a TSG or RGB three primary color signal and output to the color monitor 13, which displays five images of the subject.

In the above embodiment, since the color difference signals R-Y and B-Y are sequentially inputted to the Eitsley 912 circuit 11a, the isolation is lower than when the color difference signals R-Y and B-Y are inputted separately. The number of circuits can be reduced by one, and the number of signal lines can also be reduced.

4 to 6 relate to the second embodiment of the present invention, and FIG.
The figure is a block diagram explaining the configuration of the electronic endoscope device.
The figure is a timing chart for explaining the operation, and FIG. 6 is an explanatory diagram of the display image on the monitor.

In this embodiment, the color difference signal and the luminance signal are sequentialized by a sequential means, and only one isolation circuit 11 is provided.

In this embodiment, the structure from the high-brightness coloring prevention circuit 39 to the preceding stage is the same as that of the first embodiment, and therefore the explanation thereof will be omitted.

At J3 in FIG. 4, the sequential color difference signals R-Y/B-Y output from the three high-brightness coloring prevention circuits are input to the sequential means 53.

Here, the solid-state image sensor in the electronic endoscope is small, and in order to display various data on one screen, the display image 54 that displays the endoscopic image is mounted on the color monitor 13 as shown in FIG. It is part of the display screen 56 of. For example, the luminance signal Y output from the luminance color separation circuit 33 and the sequential color difference signal RY/B output from the high luminance coloring prevention circuit 39
-Y is expressed as an H rate as shown in FIGS. 5(a) and 5(b), for example. This image output period is usually about 60% of the period excluding the blanking period from the 1H period.

Returning to FIG. 4, the sequential color difference signal R-Y/B-Y output from the high brightness coloring prevention circuit 39 is converted into a digital signal by the A/D converter 57. The color difference signal RY/BY converted into a digital signal is input to a FIFO (first-in-first-out) memory 58 from which the input data can be read out at any timing.

The input/output timing of this FIFO memory 58 is shown in FIG.
Shown in C), (d), and (e). The figure (c) shows the timing of the write pulse of the FIFO memory 58, and the figure (d) shows the timing of the read pulse of the FIFO memory 58.
FIG. 5(e) shows the color difference signal output from the FIFO memory 58. The digitized color difference signals R-Y/8-Y are temporally sequentially input to the FIFO memory 58 by write pulses. Then, at the end of the image output period, reading is performed at twice the writing speed using a read pulse. The read output signal from the FIFO memory 58 becomes a digital signal with a waveform similar to that shown in FIG. 3(e).

When this signal is returned to an analog signal by the D/A converter 59 and added to the luminance signal Y by the adder 61, a color difference is obtained in the no-signal period other than the image output period of the luminance signal, as shown in FIG. The waveform has signals R-Y/B-Y inserted therein.

Note that the serialization means 53 includes an A/D converter 57 and an FIF.
It is composed of an O memory 58, a D/A converter 59, and an adder 61.

The added luminance/color difference synchronized signal is input to an isolation circuit 11 such as a transformer, and is designed to insulate the thinking circuit at the stage before this isolation circuit 11 from the secondary circuit at the stage after it. It has become.

Here, since the color difference signal R-Y/B-Y is read out at twice the writing speed, the band is twice the band of the color difference signal before A/D conversion.

However, the band of color difference signal R-Y/B-Y is 0°5H.
Since IIz to 1HIIZ is about 1/4 of the luminance signal band, the output of the adder 61 is below the r4 degree signal band, and the isolation circuit 11 can transmit the signal to the secondary circuit side.

On the secondary circuit side, the luminance/color difference sequential signals are branched, one is delayed for one day by a delay line 63, and the other is digitized again by an A/D converter 64.The digitized signal is The signal is input to the FIFO memory 66, and only the color difference signal is written in this FIFO memory 66 at the timing shown in FIG. It is read out at half the speed as shown in the figure (+).

The output signal of this FIFO memory 66 is sent to the D/A converter 67.
The signal is converted into an analog signal and input to the masking circuit 68 together with the output signal of the 1H delay line 63. The masking circuit 68 removes color difference components contained in the signal from the 1H delay line 63 and masks areas other than the effective image portion. The signal from the masking circuit 68 is sent to the post-processing circuit 1.
2, this signal is a signal equivalent to the luminance signal Y, which is the output of the luminance color separation circuit 33, and the color difference signal R-Y/8-Y, which is the output of the high-luminance coloration prevention circuit 39 in the patient circuit. Become.

On the other hand, a timing pulse for the secondary circuit is generated from the pulse generator 31 on the patient circuit side, which is also sent to the secondary circuit side by the pulse isolation circuit 42, inputted to the pulse generator 43 on the secondary circuit side, and then The timing pulses synchronized with the side are input to the A/D converter 64, the FIFO memory 66, the D/A converter 67, the masking circuit 68, and the post-processing circuit 12.

The signal inputted to the post-processing circuit 12 is synchronized by a synchronization circuit (not shown) using a timing pulse from a pulse generator 43, and various signal processing is performed together with the luminance signal Y, such as NTSC or RGB 3.
It is converted into a video signal such as a primary color signal and sent to the color monitor 1.
3, and the color monitor 13 displays the image of the subject 5.

In the above embodiment, since the color difference signals R-Y and B-Y are inserted into the no-signal period other than the image output period of the luminance signal Y,
The number of transmission lines for transmitting signals can be reduced to one, and further,
By using only one signal isolation circuit, it is possible to provide one signal isolation circuit for the luminance signal and the three color difference signals.

FIG. 7 is a block diagram showing a modification of the second embodiment.

In this modification, an image memory for recording video signals is provided on the secondary circuit side.

In the figure, the stage before the isolation circuit 11 is the second
This is similar to the example. The luminance/color difference synchronized signal transmitted by the isolation circuit 11 is sent to the A/D converter 73.
is converted into a digital signal by This digital signal is input to image memory 74 and stored. in this case,
The image signal is 1 HwAl! as shown in FIG. 5(f). f
Since the luminance signal and the color difference signal are present in the memory, the luminance signal and the color difference signal can be stored by performing the same operation as one frame memory or field memory that normally stores the luminance signal or the color difference signal. Therefore, the memory system that normally requires two systems, one for luminance system and one for color difference system, can be reduced to one system, and since only one system is required for driving the memory, the circuit is simplified. The signal read out from the M@memory 74 is digitally time-aligned with a luminance signal and a color difference signal in the same way as in the second embodiment by a time alignment circuit 76, and then processed by a D/A converter 77, 78. The signal is converted into an analog signal, input to the post-processing circuit 12, subjected to predetermined processing, and output. In this case, Figure 5(j)
Depending on the dynamic range of the image memory 74, a setup may be added to the color difference signal, for example, in the adder 61, and this may be stored.

8 and 9 relate to a third embodiment of the present invention, FIG. 8 is a block diagram of the endoscope apparatus, and FIG. 9 is a timing chart explaining the operation.

In this embodiment, the output image signal period of C0D7 is 50% or less of the one-day period excluding the blanking period.

In this embodiment, the structure of the stage preceding the high-brightness coloring prevention circuit 39 is the same as that of the second embodiment, and the same reference numerals are used to denote the same parts and the explanation thereof will be omitted.

The color difference signal R-Y/B-Y output from the high brightness coloring prevention circuit 39 shown in FIG. Delayed. This delayed color difference signal R-Y/B-Y is sent to the filter 6
1 output from the luminance color separation circuit 33 (a
) is added to the luminance signal Y to form a luminance/color difference sequential signal shown in FIG.

In this embodiment, the serializing means 53 is composed of a 1/2H delay line 81 and an adder 61.

On the secondary circuit side, a luminance/color difference sequential signal as shown in FIG. 9(d) is input to a 1-day delay line 82 and a 1/2H delay line 83. For the output of the 1-day delay line 82, the luminance signal has the normal timing, and for the output of the 1/2H delay line 83, the color difference signal has the normal timing. Unnecessary portions of these signals are masked by the masking circuit 68, and the signals are input to the post-processing circuit 12, subjected to predetermined processing, and output.

By configuring as described above, the luminance signal and the color difference signal can be easily sequentialized, and the isolation circuit and the storage circuit can be simplified.

In this embodiment, since the output image signal period of the CCD 7 is less than 50% of the period excluding the blanking period from the 1H period, there is no need to compress the color difference signal as in the second embodiment, and an inexpensive 1/2H A delay line 81 can be used. Therefore, costs can be further reduced.

d3. Although each of the above embodiments has been explained simply as an isolation circuit and an internal recording circuit, it can be easily applied to other transmission, storage, and storage systems.

In addition, in this embodiment, the case of a COD having a color filter array with a filter arrangement as shown in FIG. It's okay. In that case, since each pixel output is independently obtained in the baseband, the luminance/color separation circuit becomes a matrix circuit that performs time adjustment for each color and then performs the decoding of each color. In this case as well, the output of the luminance color separation circuit becomes a bright melon signal and a color difference signal sequentially, and the subsequent processing method is similar to that of this embodiment.

Further, the filter arrangement of the color filter array is not limited to that shown in FIG. 2, and the color filter array may have any filter arrangement as long as color signals are output as sequential signals.

[Effects of the Invention] As explained above, according to the present invention, the color difference signals are sequentially inputted to the isolation circuit in the patient circuit, thereby simplifying the circuit and reducing the number of signal lines and parts. Since color demodulation can also be reliably performed, image quality can be improved at low cost.

[Brief explanation of the drawing]

1 to 3 show the first embodiment of the present invention, and the first embodiment
The figure is a block diagram explaining the configuration of the electronic endoscopic 8Jt device,
Figure 2 is an explanatory diagram of the configuration of the color filter array, and Figure 3 is an electronic endoscope 1! Overall configuration diagram of the device, Figures 4 to 6
The figures 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 a timing chart explaining the operation, and FIG. 6 is a diagram of the display image of the monitor. An explanatory diagram, FIG. 7 is a block diagram showing a modification of the second embodiment, and FIGS. 8 and 9 relate to the third embodiment of the present invention.
The figure is a block diagram of the endoscope device, FIG. 9 is a timing chart diagram explaining the operation, FIGS. 10 and 11 are related to conventional examples of the electronic endoscope device, and FIG. 10 is the electronic endoscope device. FIG. 11 is a block diagram illustrating the configuration of the preprocessing circuit. 1...Electronic scope 7...Solid carrier image elements 11a, 11b...Isolation circuit 12...
Post-processing circuit 21...Electronic endoscope device 22...Camera control unit 23...Light source device 33...Brightness color separation circuit Fig. 2, Fig. 3, Fig. 5, Fig. 6, Fig. 7, Fig. 119

Claims (1)

[Claims] In an electronic endoscope apparatus having an imaging means for converting optical information into an electrical signal, and a video signal processing means for processing the electrical signal of the imaging means into a video signal, a patient circuit including the imaging means sequentially processes the electrical signal from the electrical signal. and an isolation means for subjecting the color signal to isolation processing and transmitting it to a secondary circuit system including the video signal processing means. Electronic endoscope device.