JP2648494B2 - Endoscope device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an endoscope apparatus capable of observing a change in oxygen saturation of hemoglobin in blood.

[Prior art] In recent years, by inserting an elongated insertion portion into a body cavity,
2. Description of the Related Art Endoscopes capable of observing organs in a body cavity and the like and performing various treatments using a treatment tool inserted into a treatment tool channel as necessary are widely used.

Also, various electronic endoscopes using a solid-state imaging device such as a charge-coupled device (CCD) as an imaging unit have been proposed.

In recent years, there has been proposed an endoscope apparatus for observing lesions and changes in mucous membranes, which are difficult to observe with a conventional fiberscope, using the electronic endoscope.

By the way, it is known that knowing the distribution of the oxygen saturation of hemoglobin in blood (the ratio of hemoglobin bound to oxygen in hemoglobin in blood) is useful for early detection of a lesion and the like. As a method for measuring the oxygen saturation of hemoglobin in blood, a wavelength at which the absorbance does not change due to a change in the oxygen saturation, for example, absorbance at 569 nm and 586 nm,
The wavelength at which the absorbance changes greatly due to the change in oxygen saturation,
For example, there is a method of measuring a change in oxygen saturation in the mucous membrane based on a difference from the absorbance at 577 nm.

Further, for example, in a fundus camera disclosed in Japanese Utility Model Laid-Open No. 151704/1986, an oxygen saturation image is obtained from a difference between two wavelengths.

[Problems to be Solved by the Invention] However, with a conventional oxygen saturation measuring instrument, it is possible to measure each part, but it is difficult to obtain an oxygen saturation image.

Further, as in the camera shown in the conventional example, when trying to obtain an oxygen saturation image by a wavelength at which the absorbance does not change due to a change in the oxygen saturation and a wavelength at which the absorbance greatly changes due to the change in the oxygen saturation, Since the wavelength at which the absorbance does not change due to the change in oxygen saturation is a single wavelength, a sufficient amount of light cannot be obtained, and imaging is difficult.

Further, if the wavelength region is fixed as in the camera shown in the conventional example, an image in a general visible region cannot be obtained, and a lesion cannot be detected from a subtle color tone of a mucous membrane.

[Object of the Invention] The present invention has been made in view of the above circumstances, and is intended to enable observation of an image in a general visible region and an image showing a change in oxygen saturation of hemoglobin in mucous membranes or the like. It is an object to provide an endoscope apparatus.

[Means for Solving the Problems] An endoscope apparatus according to the present invention includes an imaging unit that captures an image formed on an imaging surface, and three different wavelength regions for forming a normal visible color image. A visible color subject image forming means capable of forming a subject image on the imaging surface, and a subject image consisting of a wavelength region whose intensity changes in accordance with a change in oxygen saturation of hemoglobin in blood can be formed on the imaging surface. Image switching means for selectively forming the subject image formed by the visible color subject image forming means or the subject image formed by the oxygen saturation information image forming means on the imaging surface. Means, a color information signal generating means for generating a plurality of different color information signals based on output signals of the imaging means, and a color information signal output from the color information signal generating means. A color image signal generating means for generating a color image signal of an image formed on the imaging surface; and a difference between specific color information signals among the plurality of color information signals generated by the color information signal generating means. It is characterized by comprising a calculation means capable of calculating information, and a calculation result output means for outputting a calculation result of the calculation means.

[Operation] In the present invention, a visible color subject image forming unit and an oxygen saturation information image forming unit are provided, and a subject image composed of three different wavelength regions for forming a normal visible color image is formed on an imaging surface of the imaging unit. And it is possible to form a subject image consisting of a wavelength region in which the intensity changes in accordance with the change in oxygen saturation of hemoglobin in blood, and to select the image to be formed by the picked-up image switching means. Therefore, the output of the imaging unit that has captured the subject image selected by the captured image switching unit is input to the color information signal generation unit, and a plurality of color information signals are generated. Is generated into a color image signal by the color image signal generation means so that the color image signal can be displayed. By displaying this color image signal on a monitor, a normal visible color image or an oxygen saturation information image can be observed.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 8 relate to a first embodiment of the present invention, FIG. 1 is a block diagram showing a configuration of an endoscope apparatus, FIG. 2 is an explanatory view showing a rotary filter, and FIG. 3 is a rotary filter. 4 is an explanatory diagram showing the transmission wavelength region of each filter, FIG. 4 is an explanatory diagram showing the transmission wavelength region of each band-limiting filter, FIG. 5 is a side view showing the entire endoscope apparatus, and FIG. 6 is oxyhemoglobin. And FIG. 7 is an explanatory diagram showing an absorption spectrum of deoxyhemoglobin, FIG. 7 is an explanatory diagram showing a change in absorbance of hemoglobin due to a change in oxygen concentration, and FIG. 8 is a wavelength at which the amount of light incident on the light receiving unit does not change due to a change in oxygen saturation. FIG. 4 is an explanatory diagram showing a band.

The endoscope light device of the present embodiment includes an electronic endoscope 1 as shown in FIG. The electronic endoscope 1 has a slender, for example, flexible insertion section 2, and a large-diameter operation section 3 is connected to the rear end of the insertion section 2. A flexible universal cord 4 extends laterally from the rear end of the operation unit 3, and a connector 5 is provided at the tip of the universal cord 4. The electronic endoscope 1 includes the connector 5
, A light source device and a signal processing circuit are connected to a video processor 6 having a built-in device. Further, a monitor 7 is connected to the video processor 6.

On the distal end side of the insertion portion 2, a rigid distal end portion 9 and a bending portion 10 which can be bent rearward adjacent to the distal end portion 9 are sequentially provided. By rotating a bending operation knob 11 provided on the operation section 3, the bending section 10 is rotated.
Can be bent in the horizontal direction or the vertical direction. The operation section 3 is provided with an insertion port 12 communicating with a treatment instrument channel provided in the insertion section 2.

As shown in FIG. 1, a light guide 14 for transmitting illumination light is inserted into the insertion section 2 of the electronic endoscope 1. The distal end surface of the light guide 14 is arranged at the distal end 9 of the insertion section 2 so that illumination light can be emitted from the distal end 9. In addition, the incident end side of the light guide 14 is inserted into the universal cord 4 so that the connector 5
It is connected to the. Further, an objective lens system 15 is provided at the distal end portion 9, and at an image forming position of the objective lens system 15,
A solid-state imaging device 16 such as a CCD is provided. The solid-state imaging device 16 has sensitivity in a wide wavelength range from the visible region to the infrared region. The solid-state imaging device 16 has a signal line 2
6, 27 are connected, and these signal lines 26, 27
And is inserted into the universal cord 4 and connected to the connector 5.

On the other hand, the video processor 6 includes a lamp such as a xenon lamp that emits light in a wide band from visible light to infrared light.
21 are provided. This lamp 21 is a lamp power supply 22.
Is supplied with power. A rotary filter 50 driven by a motor 23 is provided in front of the lamp 21. As shown in FIG. 2, this rotary filter 50 has filters 50R, 50G, which transmit light in the respective wavelength regions of red (R), green (G), and blue (B) for inspection of a normal visible region. 50B and the filter 50a, 50 that transmits light of a specific wavelength region IR _1, IR _2, IR ₃ in the infrared region in order to color imaging a change in oxygen saturation of hemoglobin
b, 50c and is, 50R, 50a, 50G, 50b , 50B, in the order of 50c, _{i.e., R, IR 1, G,} IR 2, B, are arranged along the circumferential direction in the order of IR _3. FIG. 3 shows the transmission characteristics of each filter of the rotary filter 50.

The rotation of the motor 23 is controlled by a motor driver 25 to be driven.

Between the rotary filter 50 and the lamp 21, two band limiting filters 51 and 52 which are driven by a filter driving device 53 so as to be freely inserted into and removed from the illumination optical path are provided.
As shown in FIG. 4, one of the band limiting filters 51 is approximately
The bandpass filter 52 transmits the visible region of 650 nm or less, and the other band-limiting filter 52 transmits the infrared region of approximately 650 nm or more.

Further, a switching circuit 55 for switching between a normal visible image and an image indicating a change in the oxygen saturation of hemoglobin is provided,
The filter driving device 53 inserts one of the band limiting filters 51 and 52 into the illumination light path in accordance with the designation of the switching circuit 55. That is, when a normal visible image is selected, the band limiting filter 51 is inserted into the illumination light path when the image indicating a change in the oxygen saturation of hemoglobin is selected. When the band-limiting filter 51 is inserted into the illumination optical path, the illumination light is separated in time series into light of each wavelength region of R, G, and B by the rotation filter 50. When the illumination light is inserted into the optical path, the illumination light is time-separated by the rotation filter 50 into light of each wavelength region of IR ₁ , IR ₂ , and IR ₃ .

One of the band limiting filters 51 and 52 and the rotation filter 50
And light separated in a time series into light of each wavelength region of R, G, B or IR ₁ , IR ₂ , IR ₃ is incident on an incident end of the light guide 14, and this light guide 14 through the tip 9
And is emitted from the tip 9 to illuminate the observation site.

The return light from the observation site due to the illumination light is imaged on the solid-state imaging device 16 by the objective lens system 15, and is photoelectrically exchanged. This solid-state imaging device 16 includes:
A driving pulse from a driver circuit 31 in the video processor 6 is applied via the signal line 26, and reading and transferring are performed by the driving pulse. The video signal read from the solid-state imaging device 16 is
The signal is input to a preamplifier 32 provided in the video processor 6 or the electronic endoscope 1 via the signal line 27. The video signal amplified by the preamplifier 32 is input to a process circuit 33, subjected to signal processing such as γ correction and white balance, and is subjected to an A / D converter 34.
Is converted into a digital signal. The video signal which is A / D converted in time series by the A / D converter 34 is distributed by the switch circuit 35, and the video signal for each wavelength is converted into, for example, red (R), green (G), and blue, respectively. The three memories (1) 36a, the memory (2) 36b, and the memory (3) 36c corresponding to each color of (B) are selectively stored. The memory (1)
The memory 36a, the memory (2) 36b, and the memory (3) 36c are read at the same time, and are read by the D / A converters 37, 37, 37, respectively.
The signal is converted into an analog signal and input to the matrix circuit 38. When the illumination light is R, G, B, the matrix circuit 38 uses the R, G, B signals output from each of the D / A converters 37 to output a luminance signal Y and a color difference signal R-Y, B-.
And Y, while the illumination light is IR ₁ , IR ₂ , IR ₃ ,
From the pseudo-colorized R, G, B signals output from each of the D / A converters 37, a pseudo-colored luminance signal Y and color difference signals RY, BY are generated. . The luminance signal Y and the color difference signals RY, B from the matrix circuit 38
−Y is input to the encoder 39, and this encoder 39
Converts the luminance signal Y and the color difference signals RY and BY into NTSC video signals and outputs them. Then, the NTSC video signal is input to the monitor 7, and the monitor 7
Thus, the observation site is displayed in color.

The R, G, and B signals output from each of the D / A converters 37 are also input to the selector circuit 45. The selector circuit 45 selects and outputs two of the three video signals output from each of the D / A converters 37 in accordance with a selection signal from a selector (not shown). ing. The two types of video signals output from the selector circuit 45 are input to an arithmetic circuit 46. The arithmetic circuit 46 calculates the difference between the two video signals and outputs the result. The output signal of the arithmetic circuit 46 is input to a monitor, and a monochrome image indicating a change in the oxygen saturation of hemoglobin is displayed on the monitor.

In the video processor 6, a timing generator 41 for producing the timing of the entire system is provided, and the timing generator 41 synchronizes the driver circuit 31 with other circuits.

Further, the switching circuit 55 includes the R, G, B
Or IR _1, IR _2, as well as specifying whether to read the solid-state imaging device 16 in either the timing of IR _3, the switch circuit in synchronization with the timing of the reading of the solid-state imaging device 16
35 is switched.

Next, the operation of the present embodiment will be described with reference to FIGS.

First, when observing an image in a normal visible region, the band limiting filter 51 is inserted into the illumination light path. Then, the lamp 21 is turned on by the lamp power supply 22 to emit light in the visible light region to the infrared region, and the band-limiting filter 51 causes the light to enter the rotary filter 50 as light only in the visible light region. The rotary filter 50, time series R, G, performs color separation on the wavelength region of B, causes light to enter the light guide _{14, IR 1, IR 2,} IR 3 filters 50a, 50b, 50c The section is a light-shielding period, and during this light-shielding period, the solid-state imaging device 16
Each image of B can be read.

The light incident on the light guide 14 is transmitted to a site to be observed by the endoscope 1 inserted into the body cavity, and illuminates the observed tissue in time series. The reflected light at the illuminated portion is converted into an optical image by the objective lens system 15, and the optical image is photoelectrically converted by the solid-state imaging device 16. The output signal of the solid-state imaging device 16 is
The signal is processed in 3 and converted into a digital signal in the A / D converter 34. In the switch circuit 35, the R image is stored in the memory (1) 36a, the G image is stored in the memory (2) 36b, and the memory (3) 36c Are recorded respectively. These memories 36a, 36b, 36c
The video signal read out from is converted into an analog signal by the D / A converter 37, then becomes a luminance signal and a color difference signal by the matrix circuit 38, becomes an NTSC video signal by the encoder 39, and is outputted to the monitor 7. . Then, a color image in a normal visible region is displayed on the monitor 7.

On the other hand, when observing an image showing a change in the oxygen saturation of hemoglobin, the band limiting filter 52 is inserted into the illumination light path. The light in the infrared light region transmitted through the band-limiting filter 52 is time-sequentially output by the rotation filter 50 to IR ₁ , IR ₂ , IR ₃
, And is incident on the light guide 14. The section between the R, G, and B filters 50R, 50G, and 50B is a light-shielding period.

IR _1, IR _2, light reflected from a series manner illuminated observed region when the light of IR ₃ is, R, G, as in the case of illumination of B, is optically Zoka by the objective lens 15, the solid-state imaging device It is photoelectrically converted at 16. The output signal of the solid-state imaging device 16 is supplied to a preamplifier 32, a process circuit 33, an A / D converter 34, and a switch circuit 35.
After that, the image of IR ₁ and the memory (2) are stored in the memory (1) 36a.
An IR ₂ image is recorded in 36b, and an IR ₃ image is recorded in the memory (3) 36c. Each memory 36a, 36b, a video signal read from 36c is, D / in A converter 37 is an analog signal of, IR ₁ from each D / A converter 37, IR _2, images of the respective wavelength regions of IR ₃ Is output.

Here, as shown in FIGS. 6 and 7, the spectral characteristics of the absorbance of hemoglobin in blood change depending on the oxygen saturation. In the present embodiment, the rate of change is smaller than that of the narrow band IR ₁ centered at 805 nm, where the absorbance is largely changed by the oxygen saturation within the wavelength region IR ₁ within the wavelength range of 60 to 700 nm, where the absorbance hardly changes. image of each wavelength region of the oxygen saturation changes wavelength region IR ₃ differences detectable about 900~1000nm by the are each pseudo-colorized. The video signal from each of the D / A converters 37 is processed as a pseudo-color-difference signal by a matrix circuit 38, and is converted into an NTSC video signal by an encoder 39.
Is output to Then, on the monitor 7, the difference in the oxygen saturation of the tissue is displayed in a pseudo color.

By the way, the wavelength at which the absorbance does not change due to the change in oxygen saturation is a single wavelength of 800 nm, but if the light of the light source is restricted by a very narrow band filter in order to obtain this single wavelength image, the amount of light will be insufficient. It becomes difficult to visualize. Further, an error due to a slight shift in the transmission wavelength of the filter increases. Therefore, in this embodiment, as shown in FIG. 8, as a wavelength band (IR ₂ ) in which the amount of light incident on the solid-state imaging device 16 does not change due to a change in the oxygen saturation of hemoglobin,
It has set wavelength band lambda ₁ or lambda ₂ having a certain width and a shorter wavelength side and the long wavelength side of the constant absorbance point (805 nm). In the wavelength band such as λ ₁ and λ ₂ , the magnitude of the absorbance is switched with respect to the magnitude of the oxygen saturation on the short wavelength side and the long wavelength side of the equal absorbance point. Due to the change in the oxygen saturation, the amount of light incident on the solid-state imaging device 16 hardly changes. As described above, by setting a wavelength band having a certain width, a sufficient amount of light for imaging can be obtained, and an image having no practical effect on the video signal level due to a change in oxygen saturation can be obtained. .

Further, the selector circuit 45 selects two types of video signals from the video signals of each wavelength region from each D / A converter 37. For example, when the video signals of IR ₁ and IR ₂ are selected, the arithmetic circuit 46 detects a difference between the respective images, and an image of the difference is displayed on a monitor in monochrome. Therefore, with this image, the change in the oxygen saturation in the tissue can be observed with good contrast.

As described above, according to the present embodiment, it is possible to perform a conventional diagnosis based on a change in color tone in a tissue by using a color image in a general visible region, and to obtain a similar color change in the oxygen saturation of hemoglobin in the tissue. Alternatively, the image can be observed as an image with high contrast by monochrome.
Therefore, it is possible to detect a lesion at an early stage, and the diagnostic ability is improved by comparing with a conventional color image.

Incidentally, by the selector circuit 45, by selecting and displaying only IR _1, it may observe the change of the oxygen saturation.

9 to 13 relate to a second embodiment of the present invention.
FIG. 9 is a block diagram showing the configuration of the endoscope device, FIG. 10 is an explanatory diagram showing a rotating filter, FIG. 11 is an explanatory diagram showing a change in absorbance due to a change in oxygen saturation of hemoglobin, FIG.
FIG. 13 is an explanatory diagram showing a transmission wavelength region of each filter for image formation showing a change in hemoglobin oxygen saturation in the rotation filter. FIG. 13 is a transmission wavelength region of two filters of the rotation filter in a modification of the second embodiment. FIG.

In the present embodiment, the band limiting filter in the first embodiment is used.
51, 52, and the filter driving device 53 are not provided. Further, instead of the rotary filter 50, a rotary filter 60 as shown in FIG. 10 is provided. This rotary filter 60
Is a filter 60R, 60G, 60B that transmits light of each wavelength region of R, G, B for normal visible region observation, and a specific in the visible region to color change the oxygen saturation of hemoglobin into a color image. filter 60a that transmits light in the wavelength region _{G 1, G 2, G 3} ,
60b, 60c and is, 60R, 60a, 60G, 60b , 60B, in the order of 60c, _{i.e., R, G 1, G,} G 2, B, are arranged along the forward circumferentially G _3. FIG. 12 shows the wavelength ranges of G ₁ , G ₂ and G ₃ . As shown in FIGS. 11 and 12, the wavelength ranges of G ₁ , G ₂ , and G ₃ are all regions in which the absorbance changes due to the change in the oxygen saturation of hemoglobin, and G ₁ , G in between ₂ between, G _2, G _3,
In each case, the magnitude of the absorbance is replaced by the magnitude of the oxygen saturation. In the present embodiment, the lamp power supply 22
Is controlled by the switching circuit 55, and the lamp 21 is driven by the rotation filter 60 in accordance with the timing from the switching circuit 55.
Light is emitted at the timing of G ₁ , G ₂ , G ₃ or at the timing of R, G, B.

 Other configurations are the same as those of the first embodiment.

In the present embodiment, the lamp power supply 22 and the lamp 21 emit light at a timing from the switching circuit 55 with R, G, B or any combination of G ₁ , G ₂ , G ₃ , thereby causing the light guide 14 to emit light. In this case, light that is color-separated into R, G, B or G ₁ .G ₂ , G ₃ in time series is incident.

When light of R, G, and B enters, signal processing is performed in the same manner as in the first embodiment, and a color image in a general visible region is obtained. On the other hand, when observation is performed using light that has been color-separated into G ₁ , G ₂ , and G ₃ , as in the first embodiment, G ₁ , G ₂ , and G ₃ are each pseudo-colored, and the oxygen saturation ( SO ₂ ) is observed.

In addition, since the video signals of G ₁ , G ₂ , and G ₃ change due to the difference in the oxygen saturation, the difference between the two types of video selected by the selector circuit 45 is detected, so that the oxygen saturation by the monoct image is detected. The change in degree is visualized as a change in luminance.

According to this embodiment, the absorbance changes due to the change in the oxygen saturation in all the wavelength regions of G ₁ , G ₂ , and G ₃ , and G ₁ , G
Between ₂ and G ₂ and G ₃ , since the magnitude of the absorbance is exchanged for the magnitude of the oxygen saturation, the change in the oxygen saturation can be observed with a color image compared to the first embodiment. It will be easier.

In the wavelength regions of G ₁ , G ₂ , and G ₃ , the transmittance of the tissue is lower than that in the infrared light region, so that the oxygen saturation can be detected only on the tissue surface.

The wavelength ranges of G ₁ and G ₃ are λ ₄ and λ ₃ shown in FIG.
As shown in the above, the magnitude of the absorbance is exchanged for the magnitude of the oxygen saturation on the short wavelength side and the long wavelength side of the isosbestic point, so that the wavelength band where the video signal level hardly changes due to the oxygen saturation change. May be set. In this way, by setting a wavelength band having a certain width including the short wavelength side and the long wavelength side of the iso-absorbance point, a light amount sufficient for imaging can be obtained.

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

14 to 17 relate to a third embodiment of the present invention.
14 is a block diagram showing the configuration of the endoscope device, FIG. 15 is an explanatory diagram showing a mosaic filter, FIG. 16 is an explanatory diagram showing a transmission wavelength region of each filter of the mosaic filter, and FIG. 17 is a laser oscillation device FIG. 4 is an explanatory diagram showing the light emission characteristics of FIG.

The present embodiment is an example in which a simultaneous system is used as a color imaging system.

As shown in FIG. 14, as shown in FIG.
A solid-state image sensor 71 is disposed at an image forming position of the objective lens system 15 provided at the distal end portion 9 of the insertion portion.
On the front surface of 71, a mosaic filter 72 is provided.
As shown in FIG. 15, the mosaic filter 72 is configured by arranging filters that transmit light in green (G), cyan (Cy), and yellow (Ye) wavelength regions in a mosaic pattern. FIG. 16 shows the transmission wavelength region of each filter of the mosaic filter 72. As shown in this figure, in the present embodiment, each filter transmits infrared light. Other configurations of the electronic endoscope 70 are the same as those of the electronic endoscope 1 of the first embodiment.

On the other hand, on the video processor side, as a light source, a lamp 21 which is supplied with power from a lamp power supply 22 and emits a wide band of light from visible light to infrared light, and a laser oscillation having emission characteristics as shown in FIG. A device 68 is provided.
A mirror 66 whose surface on the light guide 14 side is a reflection surface is provided between the lamp 21 and the entrance end of the light guide 14 so as to be freely inserted into and removed from the illumination optical path. The mirror 66 is inserted into and removed from the illumination optical path by a mirror driving device 67. When the mirror 66 is inserted into the illumination optical path, the reflection surface is set at approximately 45 degrees with respect to the optical axis. Further, in front of the laser oscillation device 68, the light emitted from the laser oscillation device 68 is guided to a mirror 66 inserted in the illumination optical path,
A mirror 69 for allowing the light to enter the light guide 14 via the mirror 66 is provided. Thus, the mirror
When the light source 66 is retracted from the illumination light path, the light from the lamp 21 enters the light guide 14, and when the mirror 66 is inserted into the illumination light path, the light from the laser oscillator 68 is reflected by the mirrors 69 and 66. And enters the light guide 14.

The return light from the observation site due to the illumination light emitted from the light guide 14 is transmitted through the mosaig filter 72 and is imaged on the solid-state imaging device 71 by the objective lens system 15 so as to be photoelectrically converted. Has become. A driving pulse from a driver circuit 75 in the video processor is applied to the solid-state imaging device 71 via a signal line 74, and reading and transferring are performed by the driving pulse. The video signal read from the solid-state imaging device 71 is input via a signal line 73 to a preamplifier 78 provided in the video processor or the electronic endoscope. The video signal amplified by the preamplifier 78 is supplied to a low-pass filter (hereinafter, LP) for separating a luminance signal.
Write F. ) 81, an LPF 83 for separating a narrow-band luminance signal for generating a color difference signal, and a band-pass filter (hereinafter, referred to as BP) for separating a color signal modulated by a mosaicing filter 72.
Write F. ) 85 is to be entered. The LPF
The luminance signal from 81 is input to the process circuit 82, and is subjected to signal processing such as waveform shaping and γ correction. The narrow-band luminance signal from the LPF 83 is similarly input to a process circuit 84 and subjected to signal processing. The output signal of the BPF 85 is input to a 1H delay line (hereinafter, referred to as 1HDL) 86 that delays the signal by 1H period, an adder 87, and a subtractor 88. The adder 87 adds the direct signal from the BPF 85 and the signal delayed by 1H in 1HDL86, and
88 subtracts the direct signal from the BPF 85 and the signal delayed by 1H in 1HDL86. Output signals of the adder 87 and the subtractor 88 are respectively γ correction circuits 89 and 90.
, And the modulated color signals are demodulated by the demodulation circuits 91 and 92, respectively. The narrow-band luminance signal from the process circuit 84 and the color signals from the demodulation circuits 91 and 92 are input to a matrix circuit 93, and the matrix circuit 93 generates a color difference signal.
The color difference signal from the matrix circuit 93 and the process circuit
The luminance signal from 82 is input to the color encoder 94,
The color encoder 94 converts the signal into an NTSC signal. Then, the NTSC signal is input to the monitor 7, and the monitor displays the observed portion in color.

Each color signal from the process circuit 84 and the demodulation circuits 91 and 92 is also input to the selector circuit 95. The selector circuit 95 selects and outputs two of the three video signals according to a selection signal from a selection unit (not shown). The two types of video signals output from the selector circuit 95 are supplied to an arithmetic circuit 96
To be entered. The arithmetic circuit 96 calculates and outputs the difference between the two types of video signals. The output signal of the arithmetic circuit 96 is input to a monitor, and a monochrome image indicating a change in the oxygen saturation of hemoglobin is displayed on the monitor.

In the video processor, a timing generator 76 for generating the timing of the entire system is provided.
And the other circuits are synchronized.

 Next, the operation of the present embodiment will be described.

When the mirror driving device 67 retracts the mirror 66 from the illumination light path of the lamp 21, similarly to a general electronic endoscope, the image of the observation site illuminated by the illumination light of the lamp 21 is
Obtained as a visible color image.

On the other hand, when observing the change in the oxygen saturation of hemoglobin in the tissue, the mirror 66 is inserted into the illumination optical path of the lamp 21 by the mirror driving device 67, and the lamp is turned on by the lamp power supply 22.
The light 21 is turned off, and the laser oscillation device 68 emits light centered at 650 nm and light centered at 805 nm as shown in FIG. The light from the laser oscillation device 68 is a mirror
The light is reflected by 69 and 66, enters the light guide 14, and illuminates a region to be observed by the electronic endoscope 70. Here, since the laser light has a very strong energy per unit wavelength at a single wavelength, it is possible to sufficiently image by illumination with the laser light. The laser light emitted from the ride guide 14 illuminates the mucosal tissue, and the laser light near 650 nm has a large change in reflectivity due to a change in the oxygen saturation of hemoglobin in the tissue. The rate hardly changes. The light reflected from the tissue is converted into an optical image by the objective lens system 15, passes through the mosaic filter 72, and forms an image on the light receiving surface of the solid-state imaging device 71. Here, the mosaic filter 72 has a transmission characteristic as shown in FIG. 16, so that under illumination with 650 nm light, only the Ye filter is transmitted, so that the mosaic filter 72 is processed as an R signal.
In the illumination with the light of m, since the light passes through all the filters of Cy, Ye, and G, similar color processing is performed as a G signal, and the signal is output from the color encoder 94. At this time, the selector circuit 95
Then, the R and G video signals are selected, and the arithmetic circuit 96 detects the difference between these video signals, so that the difference in the oxygen saturation in the mucosal tissue can be displayed by the density difference.

Further, at the time of illumination by the lamp 21, the G and R video signals can be selected by the selector circuit 95, and the difference can be detected by the arithmetic circuit 96 to form an image.

Thus, according to the present embodiment, similarly to the first and second embodiments, it is possible to visualize the change in the oxygen saturation of hemoglobin in the mucosal tissue. Further, since color separation is not performed in time series as in the first and second embodiments, there is no time lag when performing calculations between images having different wavelengths, so that there is little calculation error.

In addition, since laser light is used, the most effective wavelength can be selected in a narrower band.

The illumination light for observing the change in the oxygen saturation of hemoglobin is not limited to laser light, and a light source such as an LED may be used.

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

The present invention is not limited to the above embodiments. For example, in the first to third embodiments, an endoscope observation site may be observed by transmitted illumination. In this case, illumination may be performed from outside the living body, or light may be guided into the living body and only the tissue may be transmitted and illuminated.

Further, the present invention is not limited to an electronic endoscope having a solid-state imaging device at the distal end portion of the insertion portion, but also to an eyepiece of an endoscope capable of visual observation such as a conventional fiberscope, or an eyepiece. The present invention can be applied to an endoscope apparatus which is exchanged and used by connecting an external television camera having a solid-state imaging device such as a CCD.

Further, the wavelength band for observing the change in the oxygen saturation of hemoglobin is not limited to that shown in each embodiment, but can be arbitrarily selected and set.

[Effects of the Invention] As described above, according to the present invention, an image in the visible region is obtained by the first wavelength separating means, and the oxygen saturation of hemoglobin is obtained by the second wavelength separating means and the third wavelength separating means. Thus, an image including a general visible region and an image indicating a change in oxygen saturation of hemoglobin in a mucous membrane or the like can be observed.

[Brief description of the drawings]

1 to 8 relate to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of the endoscope apparatus, FIG. 2 is an explanatory view showing a rotary filter, FIG. 3 is an explanatory view showing a transmission wavelength region of each filter of the rotary filter, and FIG. FIG. 5 is a side view showing the entire endoscope device, FIG. 6 is an explanatory diagram showing absorption spectra of oxyhemoglobin and deoxyhemoglobin, and FIG. 7 is a graph showing changes in oxygen concentration. FIG. 8 is an explanatory diagram showing a change in the absorbance of hemoglobin, FIG. 8 is an explanatory diagram showing a wavelength band in which the amount of light incident on the light receiving section does not change due to a change in oxygen saturation, and FIGS. 9 to 13 are second embodiments of the present invention. FIG. 9 is a block diagram showing the configuration of an endoscope apparatus,
The figure is an explanatory view showing a rotation filter, FIG. 11 is an explanatory view showing a change in absorbance due to a change in oxygen saturation of hemoglobin,
FIG. 12 is an explanatory diagram showing a transmission wavelength region of each filter for image formation showing a change in hemoglobin oxygen saturation in the rotary filter. FIG. 13 is a diagram showing transmission of two filters of a rotary filter in a modification of the second embodiment. FIG. 14 is an explanatory view showing a wavelength region, and FIGS. 14 to 17 relate to a third embodiment of the present invention.
FIG. 14 is a block diagram showing a configuration of the endoscope apparatus, FIG. 15 is an explanatory diagram showing a mosaic filter, FIG. 16 is an explanatory diagram showing a transmission wavelength region of each filter of the mosaic filter, and FIG. FIG. 4 is an explanatory diagram showing light emission characteristics of the device. DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope, 6 ... Video processor 7 ... Monitor, 15 ... Objective lens system 16 ... Solid-state image sensor, 21 ... Lamp 50 ... Rotating filter 51,52 ... Band limiting filter

Claims (1)

(57) [Claims] An image pickup means for picking up an image formed on an image pickup surface, and a visible color image capable of forming a subject image composed of three different wavelength regions for forming a normal visible color image on the image pickup surface. Subject image forming means; oxygen saturation information image forming means capable of forming a subject image consisting of a wavelength region whose intensity changes according to the change in oxygen saturation of hemoglobin in blood on the imaging surface; and the visible color subject A picked-up image switching means for selectively forming a subject image formed by an image forming means or a subject image formed by the oxygen saturation information image forming means on the imaging surface; A color information signal generating means for generating a color information signal of: a color of an image formed on the imaging surface based on the plurality of color information signals output from the color information signal generating means; Color image signal generating means for generating an image signal; calculating means capable of calculating difference information between specific color information signals among the plurality of color information signals generated by the color information signal generating means; And an operation result output means for outputting the operation result of the means.