JP3958761B2 - Dimming signal generator for endoscope - Google Patents

Description

  The present invention relates to a dimming signal generation device for dimming an illumination light amount in order to obtain an observation image having a brightness that is easy to diagnose by an endoscope.

In recent years, electronic endoscopes equipped with imaging means have been widely adopted in various endoscopic examinations and the like.
Recently, endoscope apparatuses that obtain narrow-band light observation images using narrow-band illumination light have been put into practical use.
FIG. 11 shows a schematic configuration of an endoscope apparatus 70 of a conventional example that adopts a frame sequential method and can obtain a normal light observation image and a narrow band light observation image.
The light source device 71 generates wide-band R, G, B plane-sequential illumination light during normal light observation, and generates narrow-band R, G, B plane-sequential illumination light during narrow-band light observation. Illuminate.

The illuminated subject is imaged in the frame order by the CCD 72. The CCD 72 is a CCD in which no color filter for color separation is provided on the imaging surface, that is, a monochrome CCD. The frame-sequential imaging signal photoelectrically converted by the CCD 72 is input to the CDS circuit 74 of the video processing circuit 73, and after the signal component is extracted, it is input to the A / D conversion circuit 75 and the brightness detection circuit. 76 is input.
The frame-sequential analog signal input to the A / D conversion circuit 75 is converted to a digital signal, and then input to the synchronization circuit 77 to be converted into a synchronized RGB signal. The RGB signal output from the synchronization circuit 77 is subjected to enlargement processing by the enlargement circuit 78, input to the enhancement circuit 79, subjected to edge enhancement, and then output from the output end to a monitor (not shown), in the normal light observation mode. Alternatively, the endoscopic image in the narrow-band light observation mode is displayed in color.

In addition, the luminance detection circuit 76 generates a dimming reference signal by, for example, integrating the input frame sequential R, G, and B signals, and uses the difference signal from the reference brightness value as the dimming signal. Output to the light source device 71. And the illumination light quantity by the light source device 71 is adjusted with this light control signal.
In the conventional example, the dimming reference signal generated during normal light observation was able to be adjusted appropriately.However, during narrow band light observation, the illumination light is reduced because it becomes narrow band illumination light. However, appropriate dimming cannot be performed with the same dimming reference signal generating means as in normal light observation.
Also, during normal light observation, the brightness of the image can be defined by the luminance level consisting of the entire color component signal, but in narrow band light observation, a specific color signal may be important image information. For this reason, there is a drawback that the dimming reference signal is generated in the same manner as in normal light observation, and thus dimming cannot be performed properly over a wide light amount range.

In other words, during normal light observation, dimming can be performed using the average value of each signal, but during narrow-band light observation, image information of a specific color component is important. There is a disadvantage that light cannot be performed.
In addition, as a conventional example of an endoscope apparatus that adopts a frame sequential method and can obtain a normal light observation image and a narrow-band light observation image, there is, for example, Japanese Patent Application Laid-Open No. 2002-95635. The dimming control parameters in the common dimming circuit are changed during observation and narrowband light observation.
According to the conventional example of this publication, although it can be improved as compared with the circuit configuration of FIG. 11, since a common dimming circuit is employed, even when the dimming control parameter is changed, narrowband light observation is possible. However, there is a drawback that it is difficult to adjust the light appropriately.

On the other hand, FIG. 12 shows a schematic configuration of a simultaneous conventional endoscope apparatus 80 that performs normal light observation and narrow-band light observation using an endoscope equipped with an imaging means including an optical filter.
The light source device 81 generates white illumination light during normal light observation, and generates R, G, B narrow band illumination light during narrow band light observation to illuminate the subject.
The illuminated subject is imaged by a CCD 83 provided with a color filter 82 on the imaging surface, and the imaging signal photoelectrically converted by this CCD 83 is input to the CDS circuit 85 of the video processing circuit 84 and the signal component is extracted. , The Y / C separation circuit 86 and the luminance detection circuit 87.
The imaging signal input to the Y / C separation circuit 86 is separated into a luminance signal Y and color difference signals Cr and Cb, and then input to the first matrix circuit 88 to be converted into RGB signals. This RGB signal is input to the second matrix circuit 89 and converted into a luminance signal Y and color difference signals RY and BY.

The luminance signal Y and the color difference signals RY and BY are enlarged by the enlargement circuit 90, input to the enhancement circuit 91, edge-enhanced, and then input to the third matrix circuit 92, where the RGB signal After being converted into (three primary color signals), it is output from the output end to a monitor (not shown), and the endoscopic image in the normal light observation mode or the narrow band light observation mode is displayed in color.
In addition, the luminance detection circuit 87 integrates the input CDS output signal, calculates an average value in the CDS output signal, generates a dimming reference signal, and a difference signal from the reference brightness value. Is output to the light source device 81 as a dimming signal. And the illumination light quantity by the light source device 81 is adjusted with this light control signal.
JP 2002-95635 A

  Also in the case of the simultaneous method shown in FIG. 12, a dimming reference signal is generated with a common circuit configuration for normal light observation and narrowband light observation, as described in the case of the frame sequential method. Therefore, there is a drawback that it is difficult to perform proper light control during narrowband light observation.

(Object of invention)
The present invention has been made in view of the above-described points, and provides an endoscopic dimming signal generation device capable of appropriately dimming both during normal light observation and during narrowband light observation. For the purpose.

The present invention uses a dimming reference signal generated based on a signal obtained by imaging an object illuminated by illumination light that spans a plurality of wavelength ranges by an imaging means provided in an endoscope, and uses the light control reference signal. In the dimming signal generating device for an endoscope for adjusting
The dimming reference signal was generated by changing the ratio of color signal components captured in at least multiple wavelength ranges during normal light observation with broadband illumination light and narrow band light observation with narrow band illumination light. It is characterized by.
In the above configuration, by changing the ratio of the color signal components imaged in a plurality of wavelength ranges and generating the dimming reference signal, the illumination light amount can be appropriately adjusted in each of the normal light observation and the narrow band light observation. It can be adjusted.

  According to the present invention, the dimming reference signal is generated by changing the ratio of the color signal components imaged in a plurality of wavelength ranges, so that it is appropriate for each of the normal light observation and the narrowband light observation. The amount of illumination light can be adjusted.

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

1 to 6 relate to a first embodiment of the present invention, FIG. 1 shows a configuration of an endoscope apparatus including the first embodiment of the present invention, and FIG. 2 shows a color separation filter provided in a solid-state image sensor. FIG. 3 shows the spectral characteristics of the narrow band filter, FIG. 4 shows the configuration of the dimming signal generation circuit, FIG. 5 shows a flowchart for explaining the operation of this embodiment, and FIG. Shows the configuration of the periphery of the dimming signal generation circuit in the modification.
As shown in FIG. 1, an endoscope apparatus 1 having Example 1 includes an electronic endoscope (hereinafter simply abbreviated as an endoscope) 2 that is inserted into a body cavity or the like and performs endoscopy, From the light source device 3 that supplies illumination light to the endoscope 2, the video processor 4 that drives the imaging means built in the endoscope 2 and performs signal processing on the output signal of the imaging means, and the video processor 4 A monitor 5 is provided that displays an endoscopic image captured by the imaging means when an output video signal is input.

The endoscope 2 includes an elongated insertion portion 7, an operation portion 8 provided at the rear end of the insertion portion 7, and a universal cable 9 extending from the operation portion 8. The light guide connector 11 at the end of this is detachably connected to the light source device 3, and the signal connector is detachably connected to the video processor 4.
A light guide 13 that transmits illumination light is inserted into the insertion portion 7, and the light guide connector 11 at the end on the hand side of the light guide 13 is connected to the light source device 3. Illumination light is supplied to the light guide 13.
In the normal light observation mode, the light source device 3 generates white light (visible region) illumination light as normal illumination light and supplies it to the light guide 13, and in the narrow band light observation mode, the narrow band illumination light is supplied. Generated and supplied to the light guide 13.

The switching instruction between the normal light observation mode and the narrow-band light observation mode can be performed by, for example, the mode change switch 14 such as a scope switch provided in the operation unit 8 of the endoscope 2. In addition to the scope switch provided in the endoscope 2, the mode change switch 14 may be constituted by a foot switch, or may be provided on the front panel of the video processor 4, or by a keyboard (not shown). You may comprise.
The mode switching signal from the mode switch 14 is input to the control circuit 15 in the video processor 4. When the mode switching signal is input, the control circuit 15 controls the filter insertion / removal mechanism 16 of the light source device 3. Thus, the normal illumination light and the narrow-band illumination light are selectively switched.

As will be described later, the control circuit 15 also performs control for switching the characteristics of the video signal processing system in the video processor 4 in conjunction with switching control of illumination light supplied from the light source device 3 to the light guide 13.
The light source device 3 includes a lamp 20 that generates illumination light. The lamp 20 generates illumination light that covers a visible light wavelength region (such as red, green, and blue). The illumination light is incident on the diaphragm 22 after the infrared light is cut by the infrared cut filter 21 to be substantially white illumination light. The aperture of the diaphragm 22 is controlled by a diaphragm driving circuit 23. And the illumination light quantity which passes this aperture_diaphragm | restriction 22 is controlled.
The illumination light that has passed through the diaphragm 22 passes through a narrow band filter 24 that is inserted into and removed from the illumination optical path by a filter insertion / removal mechanism 16 constituted by a plunger or the like, or without passing through the narrow band filter 24. 25, is collected by the condenser lens 25, and is incident on the end face on the hand side of the light guide 13, that is, the incident end face.

FIG. 3 shows an example of the spectral characteristics of the narrowband filter 24. The narrow band filter 24 exhibits a three-peak filter characteristic, and has, for example, narrow band transmission filter characteristic portions Ra, Ga, and Ba in red, green, and blue wavelength regions, respectively.
More specifically, the narrow-band transmission filter characteristic portions Ra, Ga, and Ba have bandpass characteristics having center wavelengths of 600 nm, 540 nm, and 420 nm, respectively, and a half width of 20 to 40 nm.
Accordingly, when the narrow band filter 24 is arranged in the illumination optical path, the three bands of narrow band illumination light transmitted through the narrow band transmission filter characteristic portions Ra, Ga, Ba are incident on the light guide 13.
On the other hand, when the narrow band filter 24 is not arranged in the illumination optical path, white light is supplied to the light guide 13.

Illumination light from the light guide 13 is transmitted to the distal end surface thereof by the light guide 13, and is emitted to the outside through an illumination lens 27 attached to an illumination window provided at the distal end portion 26 of the insertion portion 7. Illuminate the surface of living tissue.
The distal end portion 26 is provided with an observation window adjacent to the illumination window, and an objective lens 28 is attached to the observation window. The objective lens 28 forms an optical image by reflected light from the living tissue. A charge coupled device (abbreviated as CCD) 29 is disposed as a solid-state imaging device at the imaging position of the objective lens 28, and photoelectric conversion is performed by the CCD 29.
For example, a complementary color filter shown in FIG. 2 is attached to the image pickup surface of the CCD 29 for each pixel as a color separation filter 30 for optically color separation.

This complementary color filter has four color chips of magenta (Mg), green (G), cyan (Cy), and yellow (Ye) in front of each pixel, and Mg and G alternate in the horizontal direction. In the vertical direction, Mg, Cy, Mg, Ye and G, Ye, G, Cy are arranged in the order of arrangement.
In the case of the CCD 29 using this complementary color filter, two adjacent columns of pixels in the vertical direction are added and sequentially read out. At this time, the pixel columns are shifted and read in the odd and even fields. Then, the luminance signal and the color difference signal are generated as is well known by the color separation circuit on the subsequent stage side.
The CCD 29 is connected to one end of a signal line. By connecting a signal connector to which the other end of the signal line is connected to the video processor 4, the CCD driving circuit 31 and the CDS circuit 32 in the video processor 4 are connected. Connected to.

The CCD 29 receives the CCD drive signal from the CCD drive circuit 31 and inputs the photoelectrically converted image pickup signal to the CDS circuit 32. A signal component is extracted from the image pickup signal by the CDS circuit 32 and converted into a baseband signal, which is then input to a Y / C separation / synchronization circuit 33 that performs Y / C separation and synchronization. The light is input to a dimming circuit 37 through a selector 35 and an integrating circuit 36 that constitute a dimming signal generation circuit 34 that generates an optical signal.
The Y / C separation / synchronization circuit 33 generates a luminance signal Y and a line-sequential color difference signal, and then converts the luminance signal Y and a line-sequential color difference signal through a low-pass filter (not shown). Further, for line-sequential color difference signals, the first matrix circuit together with the luminance signal Y is converted into color difference signals Cr (= 2R-G) and Cb (= 2B-G) which are synchronized using a delay line (not shown). 38.

When the normal light observation mode is switched to the narrow-band light observation mode by operating the mode switch 14, the control circuit 15 passes the color difference signals Cr and Cb in the Y / C separation / simulation circuit 33. The passband is changed to a wide band to increase its resolution (resolution).
The first matrix circuit 38 converts the input luminance signal Y and the color difference signals Cr and Cb into color signals R, G, and B, and outputs the converted color signals R, G, and B to the second matrix circuit 39. To do.
The first matrix circuit 38 converts the input luminance signal Y and color difference signals Cr and Cb into color signals R, G, and B having no color mixture.
The second matrix circuit 39 converts the color signals R, G, and B into a luminance signal Y and color difference signals RY and BY.

In this case, in the normal light observation mode, the second matrix circuit 39 converts the color signals R, G, and B into the luminance signal Y and the color difference signals RY and BY by a known method. In the mode, the matrix coefficient is changed by the control circuit 15, and the G.G. Conversion is performed to increase the ratio of the B color signal, in particular, the ratio of the shortest wavelength B color signal.
That is, in the narrow-band light observation mode, the control circuit 15 generates the luminance signal Ynbi and the color difference signals RY and BY that are obtained by increasing the weighting of the B signal in particular from the color signals R, G, and B. .
The conversion formula in this case is as follows using the matrix A and K of 3 rows and 3 columns.

  Here, the matrix K is composed of, for example, three real number coefficients k1 to k3 (other coefficient components are 0), and the long-wavelength R color signal is converted as described above by the conversion formula (1). Conversely, the weighting of the G and B color signals on the short wavelength side is increased. In the normal light observation mode, conversion is performed without the matrix K in Equation (1).

A is a matrix for converting RGB signals into Y color difference signals, and the following known calculation coefficient (2) or the like is used.

  The luminance signal Y and the color difference signals RY and BY output from the second matrix circuit 39 are input to the enlargement circuit 40 and subjected to enlargement processing. The luminance signal Y is input to the selector 35.

The output signal of the enlarging circuit 40 is input to the emphasizing circuit 41, and structure emphasis processing is performed. The output signal of the enhancement circuit 41 is input to the third matrix circuit 42. Note that only the luminance signal Y component may be enhanced by the enhancement circuit 41.
The luminance signal Y and the color difference signals RY, BY inputted to the third matrix circuit 42 are converted into color signals R, G, B by the third matrix circuit 42 and outputted to the monitor 5 from the output end. The Then, an endoscopic image captured by the CCD 29 is displayed on the display surface of the monitor 5.
The control circuit 15 controls signal selection by the selector 35 in accordance with the mode switching signal.

Specifically, when the mode is switched to the narrow-band light observation mode, the control circuit 15 causes the luminance signal Y output from the second matrix circuit 39 to pass through the selector 35 to the integration circuit 36 and the dimming circuit 37. Switch to enter. The integrating circuit 36 that integrates the input signal and outputs an average value may be an averaging circuit that generates an average value.
On the other hand, in the normal light observation mode, the control circuit 15 switches so that the output signal of the CDS circuit 32 is input to the integrating circuit 36 and the dimming circuit 37 via the selector 35.
The configuration of the dimming signal generation circuit 34 will be described with reference to FIG. 4 below. The dimming signal generation circuit 34 in this embodiment averages the output signal of the CDS circuit 32 in the normal light observation mode, and the dimming reference signal <Yn> is generated, and in the narrow-band light observation mode, the luminance signal output through the second matrix circuit 39 is averaged to generate the dimming reference signal <Ynbi>.

In the narrow band light observation mode, the second matrix circuit 39 performs conversion or the like to increase the ratio of the color signal on the short wavelength side, whereby the ratio of each color signal in the dimming reference signal <Ynbi> is adjusted to the dimming reference signal <Yn. It is different from the case of>.
FIG. 4 shows a configuration example of the dimming signal generation circuit 34.
As described above, the signal selected by the selector 35 is input to the integrating circuit 36, and the dimming reference signal <Yn> or <Ynbi> integrated and averaged at a predetermined period (<Yn in the present specification and drawings). > / <Ynbi>) and input to the subtracting circuit 45 constituting the light control circuit 37. The integration circuit 36 has a built-in S / H circuit for sampling / holding (S / H), and outputs to the subtraction circuit 45 an integration value integrated at a predetermined period by the S / H control signal Ssh from the control circuit 15. .

This subtracting circuit 45 generates a reference value (a dimming target value) corresponding to the appropriate brightness generated by the reference value generating circuit (target value generating circuit) 46 from the dimming reference signal <Yn> / <Ynbi>. A value obtained by subtracting En / Enbi is output to the aperture driving circuit 23 of the light source device 3 as a dimming signal. Note that En is a reference value in the normal light observation mode, and Enbi is a reference value in the narrow-band light observation mode. In this way, by setting the target value serving as the dimming reference in each of the normal light observation mode and the narrow-band light observation mode, dimming can be performed to an appropriate target value in each mode.
In this case, the control circuit 15 switches the selector 35 and the reference value En / Enbi with the switching control signal Sc in conjunction with the mode switching signal. Further, a control signal Ssh is applied to the integrating circuit 36 to sample / hold the dimming reference signal <Yn> / <Ynbi> integrated at a predetermined period and output it to the subtracting circuit 45.
The dimming signal output from the dimming circuit 37 is output to the aperture driving circuit 23.

The aperture drive circuit 23 adjusts the amount of illumination light by decreasing the aperture amount of the aperture 22 when the dimming signal is a positive value, for example, and conversely increasing the aperture amount of the aperture 22 when the light control signal is a negative value. The dimming reference signal <Yn> / <Ynbi> is automatically dimmed so that the reference value En / Enbi of the appropriate brightness is obtained.
With this automatic light control, the endoscopic image captured by the CCD 29 and displayed on the monitor 5 is always kept at an appropriate brightness.
Note that the three primary color signals R, G, and B that are actually input from the video signal output terminal to the R, G, and B channels of the monitor 5 are in the narrow-band light observation mode, when the formula (1) is adopted, G, B, and B signals (weighting varies depending on the coefficient), especially the ratio due to the B signal is the largest, and it is easy to identify an endoscopic image corresponding to a structure such as a capillary vessel near the living body surface by the B signal. It can be displayed in the state.

That is, the signals input to the R, G, and B channels of the monitor 5 in the narrow-band light observation mode are actually G, B, and B signals, and visibility is improved.
The effect | action by a present Example is demonstrated below with reference to FIG.
The operator connects the endoscope 2 to the light source device 3 and the video processor 4 as shown in FIG. 1 and turns on the power, whereby the control circuit 15 of the video processor 4 starts the initial setting process. As shown in step S1, as the operation mode of the light source device 3 and the video processor 4, for example, the normal light observation mode is set.
In this state, the light source device 3 is set in a state in which the narrowband filter 24 is separated from the illumination optical path as shown in FIG. 1 and performs imaging with the endoscope 2 under white illumination light. It becomes a state. In addition, each unit on the video processor 4 side is also set to perform signal processing in the normal light observation mode.

In this case, the control circuit 15 controls the signal switching of the selector 35 so that the output signal from the CDS circuit 32 is input to the integrating circuit 36 side. Then, a dimming reference signal <Yn> is generated from the output signal of the CDS circuit 32, and the dimming signal obtained by subtracting the brightness reference value En by the dimming circuit 37 is sent to the aperture driving circuit 23 of the light source device 3. The diaphragm 22 is controlled so as to have an appropriate illumination light amount.
The surgeon can perform endoscopy in an illumination state in which an image with appropriate brightness is obtained by inserting the insertion portion 7 of the endoscope 2 into the body cavity of the patient. When the operator wants to observe in more detail the running state of the blood vessels on the surface of the tissue to be examined such as the affected part in the body cavity, the operator operates the mode switch 14.
As shown in step S2, the control circuit 15 monitors whether or not the mode change switch 14 has been operated. If the mode change switch 14 has not been operated, the control circuit 15 maintains that state, and the mode change switch 14 has been operated. If so, the process proceeds to the next step S3.

In step S3, the control circuit 15 changes the operation mode of the light source device 3 and the video processor 4 to the setting state of the narrowband light observation mode.
Specifically, the control circuit 15 controls the light source device 3 so that the narrowband filter 24 is disposed in the illumination optical path as indicated by a two-dot chain line in FIG. As shown in FIG. 3, the narrow band filter 24 is arranged in the illumination optical path so that illumination is performed by the narrow band illumination light by the narrow band transmission filter characteristic portions Ra, Ga, Ba.
Further, the control circuit 15 changes the setting of each unit in the video processor 4. Specifically, the control circuit 15 sets the matrix coefficient of the second matrix circuit 39, particularly in the luminance signal Ynbi (the narrowband transmission filter characteristic unit). Change so that the ratio of the signal component by the color signal B (by Ba) increases.

In addition, the selector 35 is switched, and the luminance signal Ynbi from the second matrix circuit 39 is input to the integrating circuit 36 via the selector 35 to become a dimming reference signal <Ynbi>, and the dimming circuit 37 sets the brightness reference value Enbi. A dimming signal is generated by subtraction. The amount of illumination light is adjusted by this dimming signal. And it sets to the appropriate illumination light quantity which is easy to diagnose in this narrow band light observation mode.
In addition, by performing the change setting of the signal processing system, for example, in the narrowband light observation mode, for example, the matrix coefficient of the second matrix circuit 39 is changed so that the ratio of the signal component due to the color signal B is particularly large. In addition, it is possible to observe in a state where it is easy to identify the running state of the capillary blood vessels in the vicinity of the surface layer of the biological tissue imaged under the illumination light of B by the narrow band transmission filter characteristic unit Ba.

Further, since the band characteristics when the color difference signals Cr and Cb are generated in the Y / C separation / synchronization circuit 33 are widened, the traveling state of the capillaries and the G illumination light by the narrow band transmission filter characteristic unit Ga Therefore, it is possible to improve the resolution of the blood vessel running state or the like deeper than the surface layer imaged under.
In the next step S4, the control circuit 15 monitors whether or not the mode change switch 14 has been operated. If the mode change switch 14 has not been operated, the control circuit 15 maintains that state, and the mode change switch 14 has been operated. If so, the process returns to the next step S1.

As described above, according to the present embodiment, a dimming signal suitable for dimming is generated from each luminance signal in both the normal light observation mode and the narrow-band light observation mode. A bright endoscopic image is obtained.
In addition, the normal simultaneous color imaging function is maintained, and even in the narrow-band light observation mode, the setting of the coefficient of each part in the video processor 4 is changed, so that the observation function in the narrow-band light observation mode is sufficiently obtained. Can be secured.
Next, a specific example will be described in which the contribution ratio of each color signal for generating the light control reference signal is appropriately set in each of the normal light observation mode and the narrow band light observation mode.

FIG. 6 shows a configuration of a peripheral portion of the dimming signal generation circuit 34B in the modification. In the dimming signal generation circuit 34B, the color signals R, G, and B of the first matrix circuit 38 are input to multipliers 47a, 47b, and 47c, respectively, and coefficients output from the ROM 48 that stores the multiplication coefficients. After multiplication, the addition circuit 49 adds the values.
The ROM 48 stores the coefficient in the normal light observation mode and the coefficient in the narrow-band light observation mode, and the control circuit 15 reads the corresponding coefficient in conjunction with the mode switching signal to read the multiplier 47a, 47b and 47c.
Specifically, in the normal light observation mode, the coefficient of the ratio of 5: 9: 3 (when averaged, 5/17: 9/17: 3/17) from the ROM 48 is multiplied by multipliers 47a, 47b, After being input to 47c and multiplied by the R, G, B color signals, they are added by the adder circuit 49.

  Therefore, the dimming reference signal Yn output from the adder circuit 49 in the normal light observation mode before being averaged is Yn = 5R / 17 + 9G / 17 + 3B / 17.

In the narrow band light observation mode, the coefficient of the ratio of 0: 5: 12 (0/17: 5/17: 12/17 when averaged) is read from the ROM 48 to the multipliers 47a, 47b, 47c. After being input and multiplied by the R, G, and B color signals, they are added by the adder circuit 49.
Therefore, the dimming reference signal Ynbi output from the adder circuit 49 in the narrow-band light observation mode before being averaged is Ynbi = 0 × R / 17 + 5G / 17 + 12B / 17. In this way, the output signal Yn or Ynbi (that is, Yn / Ynbi) of the adder circuit 49 is input to the integrating circuit 36 and integrated to become the dimming reference signals <Yn> / <Ynbi>, respectively, and the dimming circuit 37 Is input.
Other configurations are the same as those of the first embodiment.

According to this modification, as in the case of the first embodiment, the dimming reference signal is generated by appropriately setting the ratio of the color signal in each of the normal light observation mode and the narrow-band light observation mode. Therefore, it is possible to obtain an image having a brightness that is easy to diagnose in each mode.
As described above, in the narrow-band light observation mode, the signal processing in which the R color signal is suppressed by the narrow-band transmission filter unit Ra is performed, so that the narrow-band filter 24 shown in FIG. You may employ | adopt the filter for narrow bands which does not have the transmission characteristic of this narrow band transmission filter part Ra. In this case, the narrowband filter becomes a bimodal filter having the narrowband transmission filter portions Ga and Ba, and the cost can be further reduced.

Next, Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 7 shows a configuration of an endoscope apparatus 1B including the second embodiment of the present invention. In the first embodiment, the simultaneous endoscope apparatus 1 that performs color imaging using the simultaneous endoscope 2 including a color filter (color separation optical filter) is used. However, in the present embodiment, the color filter is used. This is a field-sequential endoscope apparatus 1B that performs color imaging in a field-sequential manner using a field-sequential-type endoscope 2B that does not have a lens.
As shown in FIG. 7, the endoscope apparatus 1B drives an endoscope 2B, a light source device 3B that supplies illumination light to the endoscope 2B, and an imaging means built in the endoscope 2B. A video processor 4B that performs signal processing on an output signal of the imaging means, and a monitor 5 that displays an endoscopic image captured by the imaging means when a video signal output from the video processor 4B is input. ing.

The endoscope 2B employs a CCD 29 having no color separation filter 30, that is, a monochrome CCD, instead of the CCD 29 provided with the color separation filter 30 in the endoscope 2 of FIG.
In the light source device 3B, in the light source device 3 of FIG. 1, for example, a rotary filter 51 is disposed in the optical path between the diaphragm 22 and the filter 24. The rotary filter 51 is rotated at a constant speed by a motor 52. .
As shown in FIG. 8A, R, G, B filters 53R, 53B, and 53B that transmit light in the R, G, and B bands are attached to the rotary filter 51 in the circumferential direction. As shown in FIG. 8B, the transmission characteristics of these R, G, B filters 53R, 53B, 53B include transmission portions Rb, Gb, Bb that transmit the R, G, B wavelength bands over a wide band, respectively. ing.

In the normal light observation mode, a broadband R.G. signal transmitted through the R, G, B filters 53R, 53B, 53B of the rotary filter 51 is transmitted. The G and B illumination lights are supplied to the light guide 13 in the surface order.
On the other hand, in the narrowband light observation mode, a narrowband filter 24 is further arranged in the optical path, and broadband R, G, B illumination light transmitted through the R, G, B filters 53R, 53B, 53B of the rotary filter 51 is received. Further, the narrow band filter 24 converts the narrow band R, G, B illumination light to the light guide 13 in the surface order.
Further, in the video processor 4B in this embodiment, the CCD drive circuit 31 drives the CCD 29, and the image signal picked up by the CCD 29 is input to the CDS circuit 32 and subjected to CDS processing.

The output signal of the CDS circuit 32 is input to the A / D conversion circuit 54, converted into a digital signal, and input to the dimming circuit 57 through the detection circuit 56 constituting the dimming signal generation circuit 55.
The digital signal generated by the A / D conversion circuit 54 is input to the synchronization circuit 58, and R, G, and B color component images captured in frame sequential order are temporarily stored in the memory constituting the synchronization circuit 58. After that, the R, G, and B signals that are simultaneously read and synchronized are output to the matrix circuit 59.
The matrix coefficient of the matrix circuit 59 is changed by the control circuit 15 between the normal light observation mode and the narrow band light observation mode. Specifically, in the normal light observation mode, the matrix is a unit matrix, but in the narrow band light observation mode, the matrix coefficient is changed so as to have a function similar to that of the second matrix circuit 39 of the first embodiment.

The output signal of the matrix circuit 59 is subjected to enlargement processing and enhancement processing by the enlargement circuit 40 and the enhancement circuit 41, respectively, as in the first embodiment, and is then output from the output end to the monitor 5.
FIG. 9 shows a circuit example of the dimming signal generation circuit 55. The frame sequential R, G, B signals are input to, for example, a gay control amplifier (abbreviated as GCA) 61 constituting the detection circuit 56, and the gain control terminal SGC of the GCA 61 receives the gain control signal Sgc from the control circuit 15. Applied. The gain (amplification factor) of the GCA 61 when the input signal is amplified and output is variably controlled according to the signal level of the gain control signal Sgc.
The gain control signal Sgc changes for each signal period of the frame-sequential input signal. In the normal light observation mode, for example, the gain of the GCA 61 is, for example, a ratio of 5: 9: 3 with respect to the input signals of R, G, and B. Set to The ratio setting when averaging (standardization) is 5/17: 9/17: 3/17.

On the other hand, in the narrowband light observation mode, for example, the gain of the GCA 61 is set to a ratio of, for example, 0: 5: 12 with respect to the R, G, B input signals. In the ratio setting when averaged, the ratio is 0/17: 5/17: 12/17.
The output signal of the GCA 61 is input to the integration circuit 36 and integrated to generate a dimming reference signal <Yn> / <Ynbi>.
The dimming reference signal <Yn> in the normal light observation mode is <Yn> = 5 <R> / 17 + 9 <G> / 17 + 3 <B> / 17.
The dimming reference signal <Ynbi> in the narrow-band light observation mode is <Ynbi> = 0 × <R> / 17 + 5 <G> / 17 + 12 <B> / 17.

The dimming reference signal <Yn> / <Ynbi> output from the integrating circuit 36 is input to the subtracting circuit 45 constituting the dimming circuit 57, and subtracted from the reference value En / Enbi of the reference value generating circuit 46. The signal is output to the aperture driving circuit 23 as a dimming signal.
Further, the reference value E is also variably set by the switching control signal Sc from the control circuit 15 according to the normal light observation mode and the narrow band light observation mode.
Note that the detection circuit 56 may be configured by a multiplier and a coefficient unit.
According to the present embodiment having such a configuration and operation, the amount of illumination light is automatically adjusted appropriately in each of the normal light observation mode and the narrow-band light observation mode as in the modification of the first embodiment. Can do.

FIG. 10 shows a configuration of a video processor 4C according to a modification. The video processor 4C applies the dimming signal generation circuit 34 in the first embodiment, which is a simultaneous type, and includes a frame sequential dimming signal generation circuit 34C similar to the dimming signal generation circuit 34.
Therefore, the video processor 4C employs the second matrix circuit 39 of the first embodiment instead of the matrix circuit 59 in the video processor 4B of FIG. The second matrix circuit 39 converts the R, G, and B signals output from the synchronization circuit 58 into a luminance signal Y and color difference signals RY and BY.
In this case, the matrix coefficients of the second matrix circuit 39 are switched by the control circuit 15 in conjunction with the mode switching as in the first embodiment.

That is, in the normal light observation mode, the second matrix circuit 39 converts the RGB signal into the luminance signal Y and the color difference signals RY and BY, but in the narrowband light observation mode, the expression described in the first embodiment. Convert as in (1).
The luminance signal Ynbi in the narrow-band light observation mode is integrated by the integrating circuit 36 via the selector 35 constituting the dimming signal generation circuit 34C to be a dimming reference signal <Ynbi>, and is input to the dimming circuit 37. To become a dimming signal.
Further, in the normal light observation mode, the output signal of the CDS circuit 32 is integrated by the integrating circuit 36 via the selector 35 constituting the dimming signal generation circuit 34C to become the dimming reference signal <Yn>. It is input and becomes a dimming signal.

The output signal of the enhancement circuit 41 is input to the third matrix circuit 42, converted into the color signal RGB, and then output from the output end to the monitor 5.
According to the modified example having such a configuration, although it is a case of the frame sequential type, the same operation effect as the first embodiment can be obtained.
It should be noted that embodiments configured by partially combining the above-described embodiments also belong to the present invention. For example, in the second embodiment, the narrowband filter 24 does not have the transmission characteristics of the narrowband transmission filter portion Ra as described in the first embodiment, but has the narrowband transmission filter portions Ga and Ba. A filter may be used.

[Appendix]
1. 5. The light control reference signal according to claim 1, wherein the dimming reference signal is generated using color signals of G and B corresponding to the wavelength ranges of green (G) and blue (B) during narrowband light observation.
2. In Claim 1, 2, 3, and 4, the said light control reference signal is produced | generated using a gain control amplifier.
3. 5. The dimming reference signal according to claim 1, wherein the dimming reference signal is generated using a plurality of multipliers.

4). A light source device that generates illumination light spanning a plurality of wavelength ranges in order to capture an image by an imaging unit provided in the endoscope;
A signal processing device that performs signal processing on a signal imaged by the imaging unit, and an object illuminated by transmitting illumination light from the light source device;
In an endoscope apparatus provided with the dimming reference signal generation circuit provided in the signal processing device and generating a dimming reference signal to adjust the light amount of the illumination light,
The light source device can generate a wide-band illumination light and a narrow-band illumination light by switching, and the dimming reference signal generation circuit can be used for normal light observation with the wide-band illumination light and with the narrow-band illumination light. An endoscope apparatus that generates a dimming reference signal by changing a ratio of color signal components picked up in at least a plurality of wavelength ranges during narrow-band light observation.

  Normal light observation when generating a dimming reference signal that adjusts the amount of illumination light based on a signal obtained by imaging an object in a body cavity illuminated by illumination light that spans multiple wavelength ranges with an imaging means built in the endoscope By generating a dimming reference signal by changing the ratio of color signal components imaged in multiple wavelength ranges at each time and narrowband light observation, it is possible to set the appropriate illumination light quantity at each observation An easy-to-use image is obtained.

1 is a block diagram showing a configuration of an endoscope apparatus including Example 1 of the present invention. The figure which shows the structure of the filter arrangement | sequence of the color separation filter provided in the solid-state image sensor. The characteristic view which shows the spectral characteristic of the filter for narrow bands. The figure which shows the structural example of a light control signal generation circuit. The flowchart for operation | movement description of a present Example. The figure which shows the structure of the light control signal generation circuit periphery part in a modification. The block diagram which shows the structure of the endoscope apparatus provided with Example 2 of this invention. The figure which shows the structure and transmission characteristic of a rotation filter. The circuit diagram which shows the structure of a light control signal generation circuit. The block diagram which shows the structure of the video processor of a modification. FIG. 6 is a schematic configuration diagram of a conventional frame sequential endoscope apparatus. FIG. 6 is a schematic configuration diagram of a conventional simultaneous endoscope apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Endoscope apparatus 2 ... (Electronic) endoscope 3 ... Light source apparatus 4 ... Video processor 5 ... Monitor 7 ... Insertion part 8 ... Operation part 11 ... Light guide connector 13 ... Light guide 14 ... Mode switch 15 ... Control Circuit 16 ... Filter insertion / removal mechanism 20 ... Lamp 22 ... Aperture 23 ... Aperture drive circuit 24 ... Narrow band filter 28 ... Objective lens 29 ... CCD
DESCRIPTION OF SYMBOLS 30 ... Color separation filter 31 ... CCD drive circuit 32 ... CDS circuit 33 ... Y / C separation and synchronization circuit 34 ... Dimming signal generation circuit 35 ... Selector 36 ... Integration circuit 37 ... Dimming circuit 38, 39, 42 ... Matrix Circuit 45 ... Subtraction circuit Agent Patent attorney Susumu Ito

Claims (4)

Adjusting the amount of illumination light using a dimming reference signal generated based on a signal obtained by imaging an object illuminated by illumination light extending over a plurality of wavelength ranges by an imaging means provided in an endoscope In the dimming signal generation device for endoscope,
The dimming reference signal was generated by changing the ratio of color signal components captured in at least multiple wavelength ranges during normal light observation with broadband illumination light and narrow band light observation with narrow band illumination light. A dimming signal generating device for an endoscope characterized by the above.   The broadband illumination light and the narrow-band illumination light are simultaneous illumination lights that simultaneously illuminate illumination lights in a plurality of wavelength ranges, respectively, and the dimming reference signal is imaged on the short wavelength side during narrow-band light observation. The dimming signal generation device for an endoscope according to claim 1, wherein the dimming signal generation device for an endoscope is generated by making the ratio of the color signal larger than the color signal picked up on the long wavelength side.   The broadband illumination light and the narrow-band illumination light are respectively surface-sequential illumination lights that sequentially illuminate illumination lights in a plurality of wavelength ranges, and the dimming reference signal is imaged on the short wavelength side during narrow-band light observation. The dimming signal generation device for an endoscope according to claim 1, wherein the ratio is generated by making the ratio of the color signal larger than the color signal imaged on the long wavelength side.   The endoscope according to claim 1, wherein a target value when adjusting the amount of illumination light by the dimming reference signal is switched between the normal light observation and the narrow-band light observation. Dimming signal generator.

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