JP6254502B2 - Endoscope light source device and endoscope system - Google Patents

Description

  The present invention relates to an endoscope light source device and an endoscope system.

  In the medical field, diagnosis using an endoscope system including an endoscope light source device (hereinafter referred to as a light source device), an endoscope, and a processor device is widely performed. The light source device is a device that generates illumination light that irradiates an observation target such as a mucous membrane of a body cavity. As an observation mode of this endoscope system, various special observations using special light as illumination light are known in addition to normal observation using normal light (white light) as illumination light. As this special observation, there is an oxygen saturation observation.

  Oxygen saturation observation is an observation method that calculates oxygen saturation and displays an image indicating how much oxygen is contained in a blood vessel. This oxygen saturation observation is based on the property that the difference in the extinction coefficient between oxygenated hemoglobin and reduced hemoglobin in the blood vessel is large in the wavelength band of 450 to 500 nm, and the light limited to this wavelength band is used as illumination light (measurement). (Light)) (see Patent Document 1).

  On the other hand, in normal observation, as a method for suppressing a decrease in contrast between the surface mucosa and the blood vessel (hereinafter referred to as blood vessel contrast), the light reflectance difference between the blood vessel and the surrounding mucosa is reduced in a wavelength band of 460 nm or more. Based on this property, it has been proposed to reduce the intensity of the wavelength band of 460 to 500 nm from white normal light (see Patent Document 2). Thereby, the blood vessel contrast of an observation image becomes high.

  In addition, in the light source device, a broadband light source such as a xenon lamp or a white LED (Light Emitting Diode) is used, and in recent years, a plurality of color semiconductor light sources such as a blue LED, a green LED, and a red LED are being used in combination. is there. In particular, as a blue light source, a blue LED having a peak wavelength in the vicinity of 450 to 460 nm is used.

Japanese Patent No. 5303012 Japanese Patent No. 5306447

  As described in Patent Documents 1 and 2, in the oxygen saturation observation, light having a wavelength band of 450 to 500 nm is used as illumination light, whereas in normal observation with increased blood vessel contrast, 460 to 500 nm from the illumination light. The intensity of the wavelength band of 500 nm is reduced, and the wavelength band used as illumination light for blue light is different. For this reason, it is necessary to use different light source devices for normal observation and oxygen saturation observation, and there is a problem that it cannot be executed by one endoscope system.

  An object of the present invention is to provide an endoscope light source device and an endoscope system that enable both normal observation with increased blood vessel contrast and oxygen saturation observation.

  In order to achieve the above object, an endoscope light source device of the present invention includes a light source unit having a blue light source that emits blue light, blue light, first blue light, and a longer wavelength band than the first blue light. A dichroic mirror that separates the second blue light, and an intensity reduction unit that selectively reduces the intensity of the first blue light and the intensity of the second blue light.

  Blue light is preferably present with a peak wavelength between 450 and 460 nm.

  In the wavelength band of the first blue light, the absorbance due to hemoglobin is larger than that in the second blue light, and in the wavelength band of the second blue light, the absorbance due to oxyhemoglobin is preferably larger than the absorbance due to reduced hemoglobin.

  It is preferable that the wavelength at which the light transmittance and the light reflectance of the dichroic mirror match is present between 450 and 460 nm.

  The intensity reducing unit preferably includes a light shielding plate arranged on one of the first blue light and the second blue light and a light shielding plate moving mechanism for moving the light shielding plate.

  The intensity reduction unit includes a first transmittance variable unit that has variable light transmittance and reduces the intensity of the first blue light, and a second transmission that has variable light transmittance and reduces the intensity of the second blue light. You may have a rate variable part and the transmittance | permeability control part which controls the light transmittance of the 1st and 2nd transmittance variable part. The transmittance control unit may set the light transmittance to a value between 0 and 100%.

  Green light source that emits green light, red light source that emits red light, light that includes first blue light, green light, and red light as first illumination light, and light that includes second blue light as second illumination light It is preferable to provide a light source control unit that generates

  The endoscope system according to the present invention includes the endoscope light source device, an imaging unit that images an observation target irradiated with the first illumination light or the second illumination light, and outputs an image signal, and the first illumination light. A first image is generated based on an image signal obtained by imaging an observation target irradiated with light, and a second image is obtained based on an image signal obtained by imaging the observation target irradiated with second illumination light. It is preferable to include an image processing unit that generates

  It is preferable to include a display unit that displays the first image and the second image, and the display unit displays the first image and the second image simultaneously.

  The imaging unit preferably includes a blue pixel that receives blue light, a green pixel that receives green light, and a red pixel that receives red light.

  The image processing unit images the observation target irradiated with the first illumination light, and captures the first image based on the blue image signal, the green image signal, and the red image signal output from the blue pixel, the green pixel, and the red pixel, respectively. Preferably, the second image is generated by imaging an observation target that has been generated and irradiated with the second illumination light and calculating an oxygen saturation based on a blue image signal output from the blue pixel.

  The second illumination light includes normal light and measurement light. The normal light includes second blue light, green light, and red light. The measurement light includes only the second blue light. The observation object irradiated with normal light is imaged, a base image is generated based on the blue image signal, green image signal, and red image signal output from the blue pixel, green pixel, and red pixel, respectively, and the measurement light is irradiated It is preferable to capture the observed object, calculate the oxygen saturation based on the blue image signal output from the blue pixel, and generate the second image by performing image processing on the base image based on the oxygen saturation.

  A violet light source that emits violet light sensitive to blue pixels is provided, and the light source control unit preferably generates light including violet light, first blue light, green light, and red light as the first illumination light.

  It is preferable that the normal observation mode in which only the first illumination light is irradiated onto the observation target and only the first image is generated can be executed.

  According to the present invention, the dichroic mirror that separates the blue light into the first blue light and the second blue light having a longer wavelength band than the first blue light, the intensity of the first blue light, and the intensity of the second blue light. And an intensity reduction unit that selectively reduces the contrast, it is possible to perform both normal observation with increased blood vessel contrast and oxygen saturation observation.

It is an external view of an endoscope system. It is a block diagram which shows the function of an endoscope system. It is a figure which shows the spectral characteristic of a color filter. It is a figure which shows the structure of a light source part. It is a graph which shows the spectrum of purple light, blue light, green light, and red light. It is a figure which shows the optical characteristic of a 1st filter part. It is a figure which shows the optical characteristic of a 2nd filter part. It is a figure which shows the optical characteristic of a 1st dichroic mirror. It is a figure which shows the optical characteristic of a 2nd dichroic mirror. It is a figure which shows the optical characteristic of a 3rd dichroic mirror. It is a figure which shows the spectral spectrum of 1st illumination light. It is a figure which shows the wavelength dependence of the extinction coefficient of hemoglobin. It is a figure which shows the spectral spectrum of the normal light of 2nd illumination light. It is a figure which shows the spectrum of the measurement light of 2nd illumination light. It is a figure which shows the wavelength dependence of the extinction coefficient of oxyhemoglobin and reduced hemoglobin. It is a block diagram which shows the function of an oxygen saturation image generation part. It is a graph which shows the correlation of a signal ratio and oxygen saturation. It is a flowchart explaining the effect | action of an endoscope system. It is a figure which shows the structure of the light source part of 2nd Embodiment. It is a figure which shows the image display example of a monitor. It is the schematic of a capsule endoscope.

[First Embodiment]
In FIG. 1, an endoscope system 10 includes an endoscope 12, an endoscope light source device (hereinafter referred to as a light source device) 14, a processor device 16, a monitor 18, and a console 19. The endoscope 12 is optically connected to the light source device 14 and electrically connected to the processor device 16. The endoscope 12 includes an insertion portion 12a to be inserted into a subject, an operation portion 12b provided at a proximal end portion of the insertion portion 12a, a bending portion 12c and a distal end portion provided at the distal end side of the insertion portion 12a. 12d. By operating the angle knob 12e of the operation unit 12b, the bending unit 12c performs a bending operation. By this bending operation, the distal end portion 12d is directed in a desired direction.

  In addition to the angle knob 12e, the operation unit 12b is provided with a mode change switch (hereinafter referred to as mode change SW) 13a and a zoom operation unit 13b. The mode switching SW 13a is used for an observation mode switching operation. The endoscope system 10 can execute a normal observation mode and an oxygen saturation observation mode as observation modes.

  In the normal observation mode, a white light image (hereinafter referred to as a normal image) in which the blood vessel contrast on the mucous membrane surface of the living tissue is increased is displayed on the monitor 18 as a display unit. In the oxygen saturation observation mode, an oxygen saturation image is displayed on the monitor 18. An oxygen saturation image is a measurement light with a specific wavelength band for measuring oxygen saturation. The oxygen saturation of the observation target is measured by irradiating the observation target, and coloring is performed using the value of the oxygen saturation. It is an image.

  The processor device 16 is electrically connected to the monitor 18 and the console 19. The monitor 18 outputs and displays images in each observation mode and image information attached to the images. The console 19 functions as a user interface that receives input operations such as function settings. The processor device 16 may be connected to an external recording unit (not shown) for recording images and image information.

  As illustrated in FIG. 2, the light source device 14 includes a light source unit 20 that generates illumination light for illuminating an observation target, and a light source control unit 21 that controls the operation of the light source unit 20. The light source unit 20 generates first illumination light in the normal observation mode, and generates second illumination light in the oxygen saturation observation mode.

  The first and second illumination lights are incident on the light guide 23 inserted into the insertion portion 12 a via the condenser lens 22. The light guide 23 is built in the endoscope 12 and propagates the first and second illumination light to the distal end portion 12 d of the endoscope 12. A multimode fiber can be used as the light guide 23. For example, a thin fiber cable having a core diameter of 105 μm, a clad diameter of 125 μm, and a diameter of φ0.3 to 0.5 mm including a protective layer serving as an outer cover can be used as the light guide 23.

  The distal end portion 12d of the endoscope 12 is provided with an illumination optical system 30a and an imaging optical system 30b. The illumination optical system 30 a has an illumination lens 31. The first and second illumination lights propagated through the light guide 23 are irradiated to the observation target through the illumination lens 31. The imaging optical system 30 b includes an objective lens 32, a zoom lens 33, and an imaging sensor (imaging unit) 34. Return light from the observation target enters the image sensor 34 via the objective lens 32 and the zoom lens 33. As a result, an optical image to be observed is formed on the image sensor 34. The zoom lens 33 is freely moved between the tele end and the wide end by operating the zoom operation unit 13b, and enlarges or reduces the light image of the observation target formed on the image sensor 34.

  The imaging sensor 34 is a color imaging sensor, captures an optical image to be observed, and outputs an image signal. As the imaging sensor 34, a CCD (Charge Coupled Device) type imaging sensor or a CMOS (Complementary Metal-Oxide Semiconductor) type imaging sensor can be used.

  The imaging sensor 34 has a red (R) color filter having a first spectral transmission characteristic 34a, a green (G) color filter having a second spectral transmission characteristic 34b, and a blue having a third spectral transmission characteristic 34c shown in FIG. (B) a color filter. Each pixel is provided with any one color filter. That is, the imaging sensor 34 includes an R pixel (red pixel) provided with an R color filter, a G pixel (green pixel) provided with a G color filter, and a B pixel (blue pixel) provided with a B color filter. And output an RGB format image signal. This image signal is one in which any one of RGB color signals is assigned to each pixel, and includes a red image signal, a green image signal, and a blue image signal. The B pixel is sensitive to violet light in addition to blue light.

  The image signal output from the image sensor 34 is transmitted to the CDS / AGC circuit 35. The CDS / AGC circuit 35 performs correlated double sampling (CDS) and automatic gain control (AGC) on an image signal that is an analog signal. The image signal output from the CDS / AGC circuit 35 is converted into a digital image signal by the A / D converter 36. This digital image signal is input to the processor device 16.

  The processor device 16 includes an imaging control unit 40, a reception unit 41, a DSP (Digital Signal Processor) 42, a noise removal unit 43, an image processing switching unit 44, a normal image generation unit 45, and an oxygen saturation image generation. Unit 46 and video signal generation unit 47. The normal image generation unit 45 and the oxygen saturation image generation unit 46 correspond to the image processing unit described in the claims.

  The imaging control unit 40 controls the imaging timing of the observation target by the imaging sensor 34 and the output timing of the image signal from the imaging sensor 34. The receiving unit 41 receives digital RGB image signals from the endoscope 12. The DSP 42 performs various signal processing such as defect correction processing, offset processing, gain correction processing, linear matrix processing, gamma conversion processing, and demosaicing processing on the received image signal.

  In the defect correction process, the signal of the defective pixel of the image sensor 34 is corrected. In the offset process, the dark current component is removed from the RGB image signal subjected to the defect correction process, and an accurate zero level is set. In the gain correction process, the signal level is adjusted by multiplying the RGB image signal after the offset process by a specific gain value. The RGB image signal after the gain correction process is subjected to a linear matrix process for improving color reproducibility. After that, brightness and saturation are adjusted by gamma conversion processing. The RGB image signal after the linear matrix processing is subjected to demosaic processing (also referred to as isotropic processing or synchronization processing), and signals of RGB colors are generated for each pixel.

  The noise removal unit 43 removes noise by performing noise removal processing (processing by a moving average method, a median filter method, or the like) on the RGB image signal subjected to demosaic processing or the like by the DSP 42. The RGB image signal from which noise has been removed is input to the image processing switching unit 44. The image processing switching unit 44 is controlled by the mode switching SW 13a. When the observation mode is set to the normal observation mode, the image processing switching unit 44 outputs the RGB image signal to the normal image generation unit 45, and when the observation mode is set to the oxygen saturation observation mode. Outputs the RGB image signal to the oxygen saturation image generation unit 46.

  The normal image generation unit 45 operates when the observation mode is set to the normal observation mode, and performs a color conversion process, a color enhancement process, and a structure enhancement process on the RGB image signal, thereby obtaining a normal image ( First image) is generated. In color conversion processing, color conversion processing is performed on RGB image signals by 3 × 3 matrix processing, gradation conversion processing, three-dimensional LUT (look-up table) processing, and the like. The color enhancement process is performed on the RGB image signal that has been subjected to the color conversion process. The structure enhancement process is a process for enhancing the structure of the observation target such as a surface blood vessel or a pit pattern, and is performed on the RGB image signal after the color enhancement process.

  The oxygen saturation image generation unit 46 operates when the observation mode is set to the oxygen saturation observation mode, calculates the oxygen saturation based on the RGB image signal, and generates the oxygen saturation image (second image). I do.

  The normal image generated by the normal image generation unit 45 and the oxygen saturation image generated by the oxygen saturation image generation unit 46 are input to the video signal generation unit 47. The video signal generator 47 converts each image into a video signal for display on the monitor 18. Using this video signal, the monitor 18 displays a normal image and an oxygen saturation image based on the video signal input from the video signal generation unit 47.

  In FIG. 4, the light source unit 20 includes a V-LED (Violet Light Emitting Diode) 50a, a B-LED (Blue Light Emitting Diode) 50b, a G-LED (Green Light Emitting Diode) 50c, and an R-LED (Red). Light Emitting Diode) 50d, LED driver 51, first to fourth collimator lenses 52a to 52d, first to fifth dichroic mirrors (DM) 53a to 53e, mirror 54, and light shielding plate 55, A light shielding plate moving mechanism 56 and a condenser lens 57 are provided.

  The V-LED 50a is a violet light source that emits violet light LV having a peak wavelength of 405 nm and a wavelength band of 380 to 420 nm. The B-LED 50b is a blue light source that emits blue light LB having a peak wavelength of 460 nm and a wavelength band of 420 to 500 nm. The G-LED 50c is a green light source that emits green light LG having a wavelength band of 480 to 600 nm. The R-LED 50d is a red light source that emits red light LR having a center wavelength of 620 to 630 nm and a wavelength band of 600 to 650 nm.

  The LED drive unit 51 drives the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d, respectively. Each emission intensity spectrum of the purple light LV, the blue light LB, the green light LG, and the red light LR is distributed as shown in FIG. The peak wavelength of the violet light LV and the peak wavelength of the blue light LB each have a wavelength width of about ± 5 nm to ± 10 nm.

  The first to fourth collimator lenses 52a to 52d are disposed so as to correspond to the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d, respectively, and the purple light LV, the blue light LB, the green light LG, Each of the red lights LR is collimated.

  The first DM 53a is arranged so that the blue light LB is incident at an angle of 45 ° on the optical path of the blue light LB emitted from the B-LED 50b. As shown in FIG. 6, the first DM 53a has a threshold λ1 at about 460 nm, transmits light having a wavelength longer than the threshold λ1, and reflects light having a wavelength shorter than the threshold λ1. Strictly speaking, the light transmittance and the light reflectance of the first DM 53a do not change from 0% to 100% at the threshold λ1, and a change from 0% to 100% requires, for example, about 50 nm. For this reason, here, the wavelength at which the light transmittance and the light reflectance of the first DM 53a match, that is, the wavelength at which the light transmittance and the light reflectance are approximately 50% is defined as the threshold value λ1.

  Further, the threshold value λ1 of the first DM 53a substantially coincides with the peak wavelength 460 nm of the blue light LB. Therefore, as shown in FIG. 7, the first DM 53a separates the blue light LB into the first blue light LB1 and the second blue light LB2 having a longer wavelength band than the first blue light LB1. The first blue light LB1 is a component reflected by the first DM 53a in the blue light LB and has a wavelength band of about 460 nm or less. The second blue light LB2 is a component that transmits the first DM 53a in the blue light LB and has a wavelength band of about 460 nm or more.

The first blue light LB1 and the second blue light LB2 have a wavelength width that varies from 0% to 100% of the light transmittance and light reflectance of the first DM 53a, so that the wavelength bands partially overlap. Further, the first blue light LB1 each peak intensity of the second blue light LB2 is lower than the peak intensity _{I P} of the blue light LB.

  The first blue light LB1 is emitted from the first DM 53a in a direction orthogonal to the optical path of the blue light LB. The mirror 54 is arranged so that the first blue light LB1 is incident at an angle of 45 °, and reflects the first blue light LB1 to change the optical path by 90 °. As a result, the optical path of the first blue light LB1 is substantially parallel to the optical path of the second blue light LB2.

  The light shielding plate 55 is a straight line between the first position where the light path of the first blue light LB1 is shielded by the light shielding plate moving mechanism 56 and the second position where the light path of the second blue light LB2 is shielded. It is moved (sliding) and shields either the first blue light LB1 or the second blue light LB2. Thus, in this embodiment, the light shielding plate 55 and the light shielding plate moving mechanism 56 selectively select the intensity of the first blue light LB1 and the intensity of the second blue light LB2 described in the claims. The strength reduction part to reduce is comprised.

  The second DM 53b is arranged so that the first blue light LB1 is incident on one surface at an angle of 45 °, and the violet light LV emitted from the V-LED 50a is incident on the other surface at an angle of 45 °. . As shown in FIG. 8, the second DM 53b has a threshold λ2 at about 425 nm, transmits light having a wavelength shorter than the threshold λ2, and reflects light having a wavelength longer than the threshold λ2. With this configuration, the second DM 53b integrates the optical path of the first blue light LB1 and the optical path of the purple light LV.

  In the third DM 53c, the second blue light LB2 is incident on one surface at an angle of 45 °, and the first blue light LB1 and the violet light LV emitted from the second DM 53b are incident on the other surface at an angle of 45 °. Is arranged. The third DM 53c has the same optical characteristics (see FIG. 6) as the first DM 53a. Accordingly, the third DM 53c has a characteristic of transmitting the second blue light LB2 and reflecting the first blue light LB1 and the violet light LV, and integrates these optical paths.

  As shown in FIG. 9, the fourth DM 53d has a threshold λ3 at about 600 nm, transmits light having a wavelength shorter than the threshold λ3, and reflects light having a wavelength longer than the threshold λ3. With this configuration, the optical path of the green light LG emitted from the G-LED 50c and the optical path of the red light LR emitted from the R-LED 50d are integrated.

  As shown in FIG. 10, the fifth DM 53e has a threshold λ4 at about 490 nm, transmits light having a wavelength longer than the threshold λ4, and reflects light having a wavelength shorter than the threshold λ4. With this configuration, the fifth DM 53e integrates the optical path integrated by the third DM 53c and the optical path integrated by the fourth DM 53d.

  The condenser lens 57 is disposed in the vicinity of the incident end of the light guide 23, condenses the light emitted from the fifth DM 53 e, and makes it incident on the incident end of the light guide 23.

  The LED driving unit 51 and the light shielding plate moving mechanism 56 are controlled by the light source control unit 21. The light source control unit 21 controls the LED driving unit 51 and the light shielding plate moving mechanism 56 according to the observation mode. Specifically, in the normal observation mode, the light source control unit 21 controls the light shielding plate moving mechanism 56 to arrange the light shielding plate 55 at the second position that shields the optical path of the second blue light LB2. In addition, by controlling the LED driving unit 51, all the light sources of the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d are turned on.

  As a result, in the normal observation mode, the first illumination light having the light intensity spectrum shown in FIG. 11 is emitted from the light source unit 20 and supplied to the light guide 23 via the condenser lens 57. The first illumination light is substantially white light. In this way, the blue light LB is band-limited to the first blue light LB1 in the normal observation mode because the light in the wavelength band of 460 to 500 nm reduces the contrast between the structure of the surface blood vessels and pit patterns and the mucous membrane. Because it will let you. As shown in FIG. 12, the wavelength band of the first blue light LB1 has higher absorbance due to hemoglobin (oxygenated hemoglobin or reduced hemoglobin) than the wavelength band of the second blue light LB2. Here, the absorbance means the ratio of light absorbed by hemoglobin and is synonymous with the extinction coefficient.

  The first DM 53a separates the blue light LB into the first blue light LB1 and the second blue light LB2, but actually, it is not completely separated into the first blue light LB1 and the second blue light LB2. The second blue light LB2 is slightly present in the optical path of the first blue light LB1, and the first blue light LB1 is slightly present in the optical path of the second blue light LB2. For this reason, the first illumination light does not have a discrete wavelength band as shown in FIG. The absence of discrete wavelength bands in the spectral spectrum of the illumination light applied to the observation target is also preferable from the viewpoint of maintaining color rendering properties with a xenon light source.

  On the other hand, in the oxygen saturation observation mode, the light source control unit 21 causes the light source unit 20 to emit the second illumination light. The second illumination light includes normal light and measurement light. In the oxygen saturation observation mode, the light source control unit 21 controls the light shielding plate moving mechanism 56 to place the light shielding plate 55 at the first position where the optical path of the first blue light LB1 is shielded. The first light emission mode for emitting normal light and the second light emission mode for emitting measurement light are alternately executed.

  In the first light emission mode, the light shielding plate 55 is disposed at the first position that shields the optical path of the first blue light LB1, and all the light sources of the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d. Lights up. As a result, in the normal observation mode, normal light having the light intensity spectrum shown in FIG. 13 is emitted from the light source unit 20 and supplied to the light guide 23 via the condenser lens 57.

  The second light emission mode is a light emission mode for measuring oxygen saturation. In the second light emission mode, the light source control unit 21 controls the LED drive unit 51 while keeping the light shielding plate 55 in the first position where the light path of the first blue light LB1 is shielded. The LED 50b is turned on, and the V-LED 50a, the G-LED 50c, and the R-LED 50d are turned off. As a result, in the second light emission mode, the measurement light having the light intensity spectrum shown in FIG. 14 is emitted from the light source unit 20 and supplied to the light guide 23 via the condenser lens 57.

  Thus, in the normal observation mode, the first illumination light is irradiated on the observation target. At this time, the imaging sensor 34 receives the return light of the purple light LV and the first blue light LB1 from the observation target by the B pixel, outputs a B image signal, and outputs the return light of the green light LG from the observation target G. The pixel receives light and outputs a G image signal, and the R pixel receives the return light of the red light LR from the observation target and outputs an R image signal.

  On the other hand, in the oxygen saturation observation mode, the observation object is irradiated with the second illumination light. Specifically, in the first light emission mode in the oxygen saturation observation mode, the observation target is irradiated with normal light. At this time, the imaging sensor 34 receives the return light of the purple light LV and the second blue light LB2 from the observation target by the B pixel, outputs a B image signal, and outputs the return light of the green light LG from the observation target G. The pixel receives light and outputs a G image signal, and the R pixel receives the return light of the red light LR from the observation target and outputs an R image signal. Hereinafter, the B image signal, the G image signal, and the R image signal in the first light emission mode are respectively referred to as a first blue image signal (B1 image signal), a first green image signal (G1 image signal), and a first red image signal ( R1 image signal).

  In the second light emission mode in the oxygen saturation observation mode, the observation target is irradiated with measurement light. Since the measurement light is composed of the second blue light LB2, the imaging sensor 34 receives the return light of the second blue light LB2 from the observation target by the B pixel and outputs a B image signal. Hereinafter, the B image signal in the second light emission mode is referred to as a second blue image signal (B2 image signal). The imaging sensor 34 can output a G image signal and an R image signal even in the second light emission mode, but these are not used for calculation of oxygen saturation or generation of an oxygen saturation image. In the embodiment, in the second light emission mode, the imaging sensor 34 outputs only the B2 image signal.

  The second blue light LB2 has a specific wavelength band for measuring oxygen saturation. This specific wavelength band is a wavelength band in which there is a difference between the extinction coefficient of oxyhemoglobin and the extinction coefficient of reduced hemoglobin to such an extent that the amount of absorption varies depending on the oxygen saturation.

As shown in FIG. 15, the magnitude relationship between the extinction coefficient A1 of oxyhemoglobin and the extinction coefficient A2 of reduced hemoglobin varies depending on the wavelength band, and matches at a plurality of wavelengths. The wavelength at which the extinction coefficient A1 of oxyhemoglobin matches the extinction coefficient A2 of reduced hemoglobin is referred to as an isosbestic wavelength. For example, in the wavelength band from purple to blue, there are first to third equivalent absorption wavelengths λ _{E1 to} λ _E3 . The first to third isosbestic wavelengths λ _{E1 to} λ _E3 are about 420 nm, about 450 nm, and about 500 nm, respectively. In the wavelength band (420 to 450 nm) between the first isosbestic wavelength λ _E1 and the second isosceles wavelength λ _E2 , the relationship is A2> A1. In the wavelength band (450 to 500 nm) between the second equal absorption wavelength λ _E2 and the third equal absorption wavelength λ _E3 , the relationship is A1> A2.

Since the second blue light LB2 has a wavelength band of 460 to 500 nm and is present between the second equal absorption wavelength λ _E2 and the third equal absorption wavelength λ _E3 , it does not include any equal absorption wavelength. The absorbance due to oxyhemoglobin is larger than the absorbance due to reduced hemoglobin (A1> A2). The second blue light LB2 has a large difference between the extinction coefficient A1 of oxyhemoglobin and the extinction coefficient A2 of reduced hemoglobin, and is suitable as measurement light for measuring oxygen saturation.

On the other hand, the first blue light LB1 has a wavelength band (420 to 460 nm) including at least the peak wavelength λ _P2 of the absorption coefficient A2 of reduced hemoglobin, and the absorbance by reduced hemoglobin is higher than that of the second blue light LB2. Big light. At the same time, the first blue light LB1 is light having higher absorbance due to hemoglobin (oxygenated hemoglobin or reduced hemoglobin) than the second blue light LB2. As described above, the first blue light LB1 is light that has a large absorbance due to hemoglobin and is easily absorbed by hemoglobin. On the other hand, the first blue light LB1 is reflected without being absorbed so much by the mucosa around the blood vessel, thereby contributing to an improvement in blood vessel contrast.

  In the wavelength band of the first blue light LB1, the absorbance due to oxidized hemoglobin is smaller than the absorbance due to reduced hemoglobin (A1 <A2). Thus, the first blue light LB1 is a light having a large difference between the absorption coefficient A1 of oxidized hemoglobin and the absorption coefficient A2 of reduced hemoglobin, but is easily absorbed by hemoglobin, and the return light from the observation target is small. It is not preferable as measurement light for measuring oxygen saturation.

  In the oxygen saturation observation mode, the imaging control unit 40 receives the synchronization signal from the light source control unit 21 (or by inputting the synchronization signal to the light source control unit 21), and performs the imaging operation of the imaging sensor 34 from the light source unit 20. Are synchronized with the light emission period of the normal light and the measurement light. Specifically, the imaging control unit 40 causes the imaging sensor 34 to image the observation target irradiated with the normal light during the first light emission period in which the normal light is emitted from the light source unit 20, and the B1 image signal and the G1 image The signal and the R1 image signal are output. Further, the imaging control unit 40 causes the imaging sensor 34 to image the observation target irradiated with the measurement light and output a B2 image signal during the second light emission period in which the measurement light is emitted from the light source unit 20.

  In FIG. 16, the oxygen saturation image generation unit 46 includes a signal ratio calculation unit 60, a correlation storage unit 61, an oxygen saturation calculation unit 62, a color conversion processing unit 63, a color enhancement processing unit 64, and a structure. An enhancement processing unit 65 and an image generation unit 66 are provided.

  The signal ratio calculation unit 60 calculates a signal ratio used by the oxygen saturation calculation unit 62 to calculate the oxygen saturation. Specifically, the signal ratio calculation unit 60 compares the ratio of the B2 image signal obtained by imaging the observation target in the second light emission mode and the G1 image signal obtained by imaging the observation target in the first light emission mode (hereinafter referred to as “the second light emission mode”). , First signal ratio B2 / G1) for each pixel. Further, the ratio of the R1 image signal and the G1 image signal obtained by imaging the observation target in the first light emission mode (hereinafter referred to as the second signal ratio R1 / G1) is calculated for each pixel.

  The correlation storage unit 61 stores a correlation between each signal ratio calculated by the signal ratio calculation unit 60 and the oxygen saturation. As shown in FIG. 17, this correlation is stored in a two-dimensional table in which isolines of oxygen saturation are defined in a two-dimensional space. The positions and shapes of the isolines with respect to the signal ratio are obtained in advance by a physical simulation of light scattering. The interval between the isolines changes according to the second signal ratio R1 / G1 representing the blood volume. Note that the correlation between the signal ratio and the oxygen saturation is stored on a log scale.

  This correlation is closely related to the light absorption characteristics (see FIG. 15) and light scattering characteristics of oxyhemoglobin and reduced hemoglobin. In the wavelength band of the second blue light LB2 where the difference in extinction coefficient between oxyhemoglobin and reduced hemoglobin is large, it is easy to obtain oxygen saturation information. However, the B2 image signal obtained from the second blue light LB2 is only oxygen saturation. It is also highly dependent on blood volume. For this reason, in addition to the B2 image signal, the second signal ratio R1 / G1 obtained from the G1 image signal that changes mainly depending on the blood volume and the R1 image signal that has a low dependence on oxygen saturation and blood volume. Is used to accurately determine the oxygen saturation.

The oxygen saturation calculation unit 62 refers to the correlation stored in the correlation storage unit 61 and corresponds to the first signal ratio B2 / G1 and the second signal ratio R1 / G1 calculated by the signal ratio calculation unit 60. Calculate the oxygen saturation. For example, in the case of the first signal ratio B2 ^* / G1 ^* and the second signal ratio R1 ^* / G1 ^* shown in FIG. 17, the oxygen saturation is calculated as “60%”.

  Note that the first signal ratio B2 / G1 or the second signal ratio R1 / G1 is hardly calculated to be extremely large or extremely small. Specifically, in FIG. 17, the coordinates represented by the first signal ratio B2 / G1 and the second signal ratio R1 / G1 exceed the lower limit isoline representing 0% oxygen saturation, or 100% It is rare that it falls below the upper isoline representing the oxygen saturation. However, as a precaution, the oxygen saturation calculation unit 62 outputs the oxygen saturation as 0% when the calculated oxygen saturation is less than 0%, and the calculated oxygen saturation exceeds 100%. Is configured to output with an oxygen saturation of 100%.

  As described above, the oxygen saturation image generation unit 46 calculates the oxygen saturation by the signal ratio calculation unit 60, the correlation storage unit 61, and the oxygen saturation calculation unit 62, while the color conversion processing unit 63 and the color enhancement processing. The unit 64 and the structure enhancement processing unit 65 generate an image (hereinafter referred to as a base image) as a base of the oxygen saturation image.

  The color conversion processing unit 63 performs 3 × 3 matrix processing, gradation conversion processing, and three-dimensional LUT on the B1 image signal, G1 image signal, and R1 image signal obtained by imaging the observation target in the first light emission mode. Color conversion processing is performed by processing. The color enhancement processing unit 64 performs color enhancement processing on the B1 image signal, G1 image signal, and R1 image signal that have undergone color conversion processing. The structure enhancement processing unit 65 performs structure enhancement processing for enhancing the structure of an observation target such as a surface blood vessel or a pit pattern on the B1 image signal, the G1 image signal, and the R1 image signal that have been subjected to the color enhancement processing. That is, the base image is generated by a B1 image signal, a G1 image signal, and an R1 image signal that have been subjected to various image processes similar to those of the normal image generation unit 45.

  The image generation unit 66 uses the oxygen saturation calculated by the oxygen saturation calculation unit 62 and the B1 image signal, the G1 image signal, and the R1 image signal that have been subjected to the above-described various image processing, to observe the oxygen saturation of the observation target. An oxygen saturation image representing degrees is generated. Specifically, the image generation unit 66 applies a gain corresponding to the oxygen saturation to the B1 image signal, the G1 image signal, and the R1 image signal for each pixel.

  For example, the image generation unit 66 sets the gain for the B1 image signal, the G1 image signal, and the R1 image signal to “1” for a pixel having an oxygen saturation of 60% or more, and does not substantially perform gain processing. On the other hand, for pixels with oxygen saturation less than 60%, using the value of oxygen saturation, the gain for the B1 image signal is less than “1”, and the gain for the G1 image signal and the R1 image signal is “1”. Or more. An image represented by using the B1 image signal, the G1 image signal, and the R1 image signal after the gain processing is an oxygen saturation image. Therefore, in the oxygen saturation image, pixels with high oxygen (pixels with an oxygen saturation of 60 to 100%) are represented in the same color as the normal image, and pixels with low oxygen (pixels with an oxygen saturation of less than 60%) are displayed. Is represented by a color (pseudo color) different from that of a normal image.

  In the present embodiment, the image generation unit 66 performs gain processing according to the oxygen saturation level only for the low oxygen pixels. However, the image generation unit 66 also performs gain processing according to the oxygen saturation level for the high oxygen pixels, and oxygen saturation is performed. The entire image may be pseudo-colored. In addition, the reference value of oxygen saturation for separating low oxygen and high oxygen is 60%, but this reference value may be changed as appropriate.

  Next, a series of flows in the present embodiment will be described along the flowchart shown in FIG. First, screening is performed from a distant view state in the normal observation mode (S10). In the normal observation mode, the light shielding plate 55 is disposed at a second position that shields the optical path of the second blue light LB2. At the time of screening, when a possible lesion site (hereinafter referred to as a possible lesion site) such as a brownish area or redness is detected (S11), the zoom operation unit 13b is operated to perform observation including a possible lesion site. Perform magnified observation to zoom in on the subject. In accordance with this, the mode switching SW 13a is operated to switch the observation mode to the oxygen saturation observation mode (S12).

  When the observation mode is switched to the oxygen saturation observation mode, the light source control unit 21 arranges the light shielding plate 55 at the first position where the light path of the first blue light LB1 is shielded (S13). Then, the light source control unit 21 turns on all the light sources of the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d, thereby causing the purple light LV, the second blue light LB2, the green light LG, and the red light LR. The observation object is irradiated with normal light consisting of (S14). The imaging sensor 34 images an observation target illuminated with normal light and outputs a B1 image signal, a G1 image signal, and an R1 image signal (S15).

  Thereafter, the light source control unit 21 automatically switches the light emission mode and turns on only the B-LED 50b, thereby irradiating the observation target with the measurement light composed of the second blue light LB2 (S16). The imaging sensor 34 images the observation target illuminated with the measurement light and outputs a B2 image signal (S17).

  Thus, when the B1 image signal, the G1 image signal, and the R1 image signal are obtained in the first emission mode, and the B2 image signal is obtained in the second emission mode, the oxygen saturation image generation unit 46 performs the signal ratio calculation unit 60. To calculate the first signal ratio B2 / G1 and the second signal ratio R1 / G1 (S18), and the oxygen saturation calculation unit 62 calculates the oxygen saturation (S19). On the other hand, the oxygen saturation image generation unit 46 uses the color conversion processing unit 63, the color enhancement processing unit 64, and the structure enhancement processing unit 65 based on the B1 image signal, the G1 image signal, and the R1 image signal. A base image that is the base of the is generated.

  Then, the image generation unit 66 applies a gain corresponding to the oxygen saturation to the B1 image signal, the G1 image signal, and the R1 image signal that have been subjected to various types of image processing to generate an oxygen saturation image (S20). The oxygen saturation image is converted into a video signal by the video signal generation unit 47 and displayed on the monitor 18 (S21).

  Steps S14 to S21 in the oxygen saturation observation mode are repeated until the observation mode is switched to the normal observation mode (YES determination in S22) or the diagnosis is ended (YES determination in S23). Note that the above observation flow is an example, and observation and diagnosis using the oxygen saturation observation mode may be performed in other flows. For example, in the above-described observation flow, observation is performed in the oxygen saturation observation mode at the time of foreground observation, but observation may be performed using the oxygen saturation observation mode also when performing distant view observation for screening or the like. In the above embodiment, the observation target is imaged in the second light emission mode after the observation target is imaged in the first light emission mode. However, the observation target in the first light emission mode is captured after the observation target is imaged in the second light emission mode. May be imaged.

  As described above, different diagnostic observations are possible by selectively generating the first blue light LB1 and the second blue light LB2 based on the blue light LB emitted from the B-LED 50b. In normal observation, the first blue light LB1 in which the intensity of the wavelength component of 460 nm or more is reduced from the blue light LB is used. The first blue light LB1 is light having a higher absorbance by oxyhemoglobin than the second blue light LB2, and is easily absorbed by hemoglobin in the blood vessel (oxygenated hemoglobin or reduced hemoglobin), but is not so much in the mucosa around the blood vessel. Since it is not absorbed, a high-quality blue image component with improved blood vessel contrast can be obtained.

  On the other hand, in the oxygen saturation observation mode, the second blue light LB2 in which a component of 460 nm or less is reduced from the blue light LB is used as measurement light. The second blue light LB2 is a light that has a large difference between the extinction coefficient A1 of oxyhemoglobin and the extinction coefficient A2 of deoxyhemoglobin, is not so much absorbed by oxyhemoglobin or deoxyhemoglobin, and has a large component as return light. The oxygen saturation can be calculated with high accuracy.

  In the first embodiment, the peak wavelength of the blue light LB is 460 nm, but the peak wavelength is not limited to 460 nm. However, the peak wavelength of the blue light LB is preferably 450 nm or more, and more preferably in the range of 450 to 460 nm.

  In the first embodiment, the threshold λ1 of the first DM 53a is set to 460 nm. However, the threshold λ1 is also preferably in the range of 450 to 460 nm, and more preferably matches the peak wavelength of the blue light LB. preferable.

  In the first embodiment, the optical characteristics shown in FIGS. 6 and 8 to 10 are used as the optical characteristics of the first to fifth DMs 53a to 53e. However, the present invention is not limited to this, and the first to fifth DMs 53a to 53e are used. It is also possible to reverse the relationship between transmission and reflection for the respective optical characteristics.

  In the first embodiment, the slide-type light shielding plate 55 is used. However, instead of this, it is also possible to use a rotary light shielding plate. For example, the semicircular portion of the rotating plate is a light shielding portion, and the remaining semicircular portion is an opening portion, and the light shielding portion and the opening portion of the rotating plate rotate with respect to the first blue light LB1 and the second blue light LB2. What is necessary is just to arrange | position so that each optical path may be passed.

[Second Embodiment]
In the first embodiment, the light shielding plate 55 and the light shielding plate moving mechanism 56 constitute an intensity reducing unit. However, the intensity is varied by a transmittance variable unit such as a liquid crystal shutter whose light transmittance is electrically variable. A reduction unit may be configured. In FIG. 19, the light source unit 70 of the second embodiment replaces the light shielding plate 55 and the light shielding plate moving mechanism 56 of the light source unit 20 of the first embodiment with a first transmittance variable unit 71 and a second transmittance. A variable unit 72 and a transmittance control unit 73 are provided. In the second embodiment, the first transmittance variable unit 71, the second transmittance variable unit 72, and the transmittance control unit 73 constitute an intensity reducing unit.

  The first transmittance variable unit 71 is disposed on the optical path of the first blue light LB1. The second transmittance variable unit 72 is disposed on the optical path of the second blue light LB2. The transmittance control unit 73 controls the light transmittance of the first transmittance variable unit 71 and the light transmittance of the second transmittance variable unit 72, respectively.

  In the normal observation mode, the light source control unit 21 controls the transmittance control unit 73 to set the light transmittance of the first transmittance variable unit 71 to approximately 100% and the light transmittance of the second transmittance variable unit 72. Is set to approximately 0%, and by controlling the LED driving unit 51, all the light sources of the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d are turned on. As a result, since the intensity of the second blue light LB2 is reduced by the second transmittance variable unit 72, the first illumination light having the light intensity spectrum shown in FIG.

  In the first light emission mode of the oxygen saturation observation mode, the light source control unit 21 controls the transmittance control unit 73 so that the light transmittance of the first transmittance variable unit 71 is approximately 0%, and the second transmittance. All the light sources of the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d are turned on by setting the light transmittance of the variable unit 72 to approximately 100% and controlling the LED driving unit 51. As a result, since the intensity of the first blue light LB1 is reduced by the first transmittance variable unit 71, normal light having a light intensity spectrum shown in FIG.

  In the second light emission mode of the oxygen saturation observation mode, the light source control unit 21 sets the light transmittance of the first transmittance variable unit 71 to approximately 0% and the light transmittance of the second transmittance variable unit 72 to approximately 100%. By controlling the LED driving unit 51, only the B-LED 50b is turned on. As a result, since the intensity of the first blue light LB1 is reduced by the first transmittance variable unit 71, the measurement light having the light intensity spectrum shown in FIG.

In the second embodiment, one of the first transmittance variable unit 71 and the second transmittance variable unit 72 is approximately 100% and the other is approximately 0%. However, the first transmittance variable unit One or both of 71 and the second transmittance variable unit 72 may be a value between 0% and 100%. For example, in the normal observation mode, the light transmittance of the first transmittance variable unit 71 is set to approximately 100%, and the light transmittance of the second transmittance variable unit 72 is set to 20 to 70%. Thereby, the intensity | strength of the 460-500 nm wavelength band in 1st illumination light can be made into about 20 to 70% of the peak intensity of blue light LB, and a blood vessel can be displayed more emphasized.

  In the first and second embodiments, the imaging sensor 34 which is a primary color imaging sensor is used. Instead, C (cyan), M (magenta), Y (yellow), and G (green) are used. Alternatively, a complementary color image sensor having a complementary color filter may be used. The complementary color imaging sensor outputs an image signal in CMYG format, which can be converted into RGB format by color conversion processing. Furthermore, it is possible to use a monochrome sensor. In this case, the V-LED 50a, the B-LED 50b, the G-LED 50c, and the R-LED 50d may be lit in a time division manner. In this case, the V-LED 50a and the B-LED 50b may be turned on simultaneously.

  In the first and second embodiments, the normal image is displayed on the monitor 18 in the normal observation mode, and the oxygen saturation image is displayed on the monitor 18 in the oxygen saturation observation mode. Sometimes, as shown in FIG. 20, a normal image (first image) may be displayed on the monitor 18 in addition to the oxygen saturation image (second image). Since the normal image and the oxygen saturation image are displayed on the monitor 18 at the same time, by referring to the normal image, in the low oxygen saturation image, the source of the portion colored according to the value of the oxygen saturation is obtained. Can be confirmed.

  In the first and second embodiments, in the second light emission mode, the B-LED 50b is turned on and the V-LED 50a, the G-LED 50c, and the R-LED 50d are turned off. The blue light LB may be substantially emitted by setting these light emission amounts to extremely small values. In this way, by not turning off the V-LED 50a, the G-LED 50c, and the R-LED 50d completely, it is possible to prevent the occurrence of LED switching noise.

  In the first and second embodiments, the normal light having the light intensity spectrum shown in FIG. 13 is used as the illumination light in the first light emission mode of the oxygen saturation observation mode. Ordinary light having the light intensity spectrum shown may be used as illumination light. In this case, the first blue light LB1 is generated in the first light emission mode, and the second blue light LB2 is generated in the second light emission mode.

  In the case of the light source unit 20 of the second embodiment shown in FIG. 4, the light shielding plate 55 may be moved in accordance with the switching of the light emission mode. Specifically, in the first light emission mode, the first light blue LB1 is generated by arranging the light shielding plate 55 on the optical path of the second blue light LB2, and the light shielding plate 55 is light of the first blue light LB1. What is necessary is just to produce | generate 2nd blue light LB2 by arrange | positioning on a road.

  In the case of the light source unit 70 shown in FIG. 19, the light transmittance of the first transmittance variable unit 71 and the second transmittance variable unit 72 may be changed in accordance with the switching of the light emission mode. Specifically, in the first light emission mode, the first blue light LB1 is generated by setting the light transmittance of the first transmittance variable unit 71 to approximately 100% and the light transmittance of the second transmittance variable unit 72 to approximately 0%. In the second light emission mode, the second blue light LB2 is generated by setting the light transmittance of the first transmittance variable unit 71 to approximately 0% and the light transmittance of the second transmittance variable unit 72 to approximately 100%. good. The light transmittance of the first transmittance variable portion 71 and the second transmittance variable portion 72 is controlled by electrical control, and the light transmittance can be switched instantaneously. It is possible to increase the mode switching speed (high frame rate).

In the first light emission mode, it is also preferable that the light transmittance of the first transmittance variable unit 71 is set to approximately 100% and the light transmittance of the second transmittance variable unit 72 is set between 20 % and 70%. .

  As described above, since the first blue light LB1 is generated in the first emission mode, the base image of the oxygen saturation image is generated using normal light with reduced intensity in the wavelength range of 460 to 500 nm. The image has an improved contrast of fine structures such as surface blood vessels and pit patterns. In this way, an oxygen saturation image is generated based on a high-quality base image with improved blood vessel contrast.

  In the first and second embodiments, the endoscope system has the normal observation mode and the oxygen saturation observation mode, and further increases the intensity of the short wavelength component of the first illumination light. It is also preferable to provide a blue light observation mode. This blue light observation mode generates the first illumination light in which the intensity of the short wavelength component is increased by increasing the emission intensity of the V-LED 50a and the B-LED 50b as compared with the normal observation mode. Other configurations are the same as those in the first and second embodiments. Since the purple light LV and the first blue light LB1 included in the first illumination light are light that is easily absorbed by hemoglobin in the blood vessel of the mucosal surface layer, the surface blood vessel, the pit pattern, and the like can be further emphasized. Further, it is known that the shorter the wavelength of illumination light, the shallower the depth of penetration into the living body. Violet light can extract blood vessel information shallower than blue light. Therefore, it is possible to generate illumination light suitable for polar surface blood vessel observation by increasing the ratio of violet light to blue light.

  In the first and second embodiments, the light source device 14 and the processor device 16 are configured separately, but may be configured by a single device including the light source device and the processor device.

  In the first and second embodiments, the present invention is implemented by the endoscope system 10 that performs observation by inserting the endoscope 12 provided with the imaging sensor 34 into the subject. The present invention is also suitable for an endoscope system. For example, as shown in FIG. 24, the capsule endoscope system includes at least a capsule endoscope 100 and a processor device (not shown).

  The capsule endoscope 100 includes a light source 102, a light source control unit 103, an image sensor 104, an oxygen saturation image generation unit 106, and a transmission / reception antenna 108. The light source 102 includes a V-LED that emits purple light LV, a B-LED that emits blue light LB, a G-LED that emits green light LG, an R-LED that emits red light LR, and a blue light LB. A band limiting unit that selectively generates the blue light LB1 and the second blue light LB2, and corresponds to the light source units 20 and 70 of the first and second embodiments.

  The light source control unit 103 controls driving of the light source 102 in the same manner as the light source control unit 21 of the first and second embodiments. The light source control unit 103 can communicate wirelessly with the processor device of the capsule endoscope system by the transmission / reception antenna 108. The processor device of the capsule endoscope system is substantially the same as the processor device 16 of the first and second embodiments described above, but the oxygen saturation image generation unit 106 corresponding to the oxygen saturation image generation unit 46 is provided in the capsule. It is provided in the endoscope 100. The oxygen saturation image generated by the oxygen saturation image generation unit 106 is transmitted to the processor device via the transmission / reception antenna 108. The image sensor 104 has the same configuration as the image sensor 34 of the first and second embodiments.

DESCRIPTION OF SYMBOLS 10 Endoscope system 20 Light source part 21 Light source control part 34 Image sensor 44 Image processing switching part 45 Normal image generation part 46 Oxygen saturation image generation part 55 Light shielding board 56 Light shielding board moving mechanism 70 Light source part 71 1st transmittance | permeability Variable part 72 Second transmittance variable part 73 Transmittance control part

Claims (15)

A light source unit having a blue light source that emits blue light;
A dichroic mirror that separates the blue light into first blue light and second blue light having a longer wavelength band than the first blue light;
An intensity reducing unit that selectively reduces the intensity of the first blue light and the intensity of the second blue light;
An endoscope light source device comprising:   The endoscope light source device according to claim 1, wherein the blue light has a peak wavelength of 450 to 460 nm.   The wavelength band of the first blue light has a greater absorbance by hemoglobin than the wavelength band of the second blue light, and the wavelength band of the second blue light has a greater absorbance by oxyhemoglobin than that by reduced hemoglobin. The light source device for an endoscope according to claim 1, wherein the light source device is an endoscope.   4. The endoscope light source device according to claim 1, wherein the wavelength at which the light transmittance and the light reflectance of the dichroic mirror coincide with each other is between 450 to 460 nm. The strength reducing unit is
A light shielding plate disposed on an optical path of either the first blue light or the second blue light;
A light shielding plate moving mechanism for moving the light shielding plate;
The endoscope light source device according to claim 1, wherein the endoscope light source device is provided. The strength reducing unit is
A first transmittance variable unit that has variable light transmittance and reduces the intensity of the first blue light;
A second transmittance variable portion that has a variable light transmittance and reduces the intensity of the second blue light;
A transmittance control unit for controlling the light transmittance of the first and second transmittance variable units;
The endoscope light source device according to claim 1, wherein the endoscope light source device is provided.   The endoscope light source device according to claim 6, wherein the transmittance control unit sets the light transmittance to a value between 0% and 100%. A green light source that emits green light;
A red light source that emits red light;
A light source control unit that generates light including the first blue light, the green light, and the red light as the first illumination light, and generates light including the second blue light as the second illumination light;
The endoscope light source device according to any one of claims 1 to 7, further comprising: An endoscope light source device according to claim 8,
An imaging unit that images an observation target irradiated with the first illumination light or the second illumination light and outputs an image signal;
The first image is generated based on the image signal obtained by imaging the observation object irradiated with the first illumination light, and the observation object irradiated with the second illumination light is imaged. An image processing unit for generating a second image based on the image signal;
An endoscope system comprising: A display unit for displaying the first image and the second image;
The endoscope system according to claim 9, wherein the display unit simultaneously displays the first image and the second image.   The said imaging part has a blue pixel which receives the said blue light, a green pixel which receives the said green light, and a red pixel which receives the said red light, The inside of Claim 9 or 10 characterized by the above-mentioned. Endoscopic system. The image processing unit
The observation object irradiated with the first illumination light is imaged, and the first image is obtained based on the blue image signal, the green image signal, and the red image signal respectively output from the blue pixel, the green pixel, and the red pixel. Generate
12. The observation object irradiated with the second illumination light is imaged, oxygen saturation is calculated based on a blue image signal output from the blue pixel, and the second image is generated. The endoscope system described in 1. The second illumination light includes normal light and measurement light, and the normal light includes the second blue light, the green light, and the red light, and the measurement light includes only the second blue light. Become
The image processing unit
Imaging the observation object irradiated with the normal light, generating a base image based on the blue image signal, the green image signal, and the red image signal output from the blue pixel, the green pixel, and the red pixel,
Imaging the observation object irradiated with the measurement light, calculating the oxygen saturation based on a blue image signal output from the blue pixel,
The endoscope system according to claim 12, wherein the second image is generated by performing image processing on the base image based on the oxygen saturation. A purple light source that emits purple light sensitive to the blue pixels,
The light source control unit generates light including the violet light, the first blue light, the green light, and the red light as the first illumination light. The endoscope system described in 1.   The endoscope system according to any one of claims 9 to 14, wherein a normal observation mode in which only the first illumination light is irradiated onto an observation target and only the first image is generated can be executed.

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