JP6438322B2 - Endoscope system - Google Patents

Description

  The present invention relates to an endoscope system having an addition type light source.

  In the medical field, diagnosis using an endoscope system including a light source device, an endoscope, and a processor device is widely performed. The illumination light generated by the light source device is applied to the observation target from the distal end portion of the endoscope via a light guide in the endoscope. An imaging device is built in the distal end portion of the endoscope, and return light from the observation target is received by the imaging device. The processor device performs image processing on an image signal obtained by the imaging element to generate an observation image.

  As the light source device, a broadband light source that emits white broadband light such as a xenon lamp is widely used. In recent years, an addition method light source (hereinafter referred to as an addition method light source) that generates illumination light by combining a plurality of light sources that emit light in a specific wavelength band such as red, green, and blue and adding the light emitted from each light source. ) Is being used. In the addition method light source, a semiconductor light source such as a red LED (Light Emitting Diode), a green LED, or a blue LED is used. Addition of light from each light source is performed using a dichroic mirror (see, for example, Patent Document 1).

  Also, in an endoscope system, depending on the purpose of diagnosis, a pigment such as pioctanin or indigo carmine is sprayed on an observation target, and the observation target colored with the pigment is imaged by an image sensor. For example, by dispersing pioctanin on the large intestine as an observation target, the lesion is stained blue-purple and the surface pattern is clarified. The nature of the lesion (whether benign or malignant) can be determined from this pattern.

Japanese Patent No. 5654167

  The dyed portion with picotanine is observed as a bluish purple color when using a broadband light source, but the color tone may change and the color tone may be shifted to the blue side when an additive light source is used. This is because the red LED, which is the red light source of the addition method light source, has a narrow wavelength band, and the amount of light on the long wavelength side is less than the illumination light of the broadband light source. In particular, although octanonin has a certain reflectance in a short wavelength band of about 500 nm or less and a long wavelength band of about 650 nm or more, the illumination light of the addition method light source has almost no wavelength component in the long wavelength band. Since it is not included, redness is insufficient and the color changes.

  Thus, doctors accustomed to observation with an endoscope system having a conventional broadband light source, when observing with an endoscope system having an addition method light source, the color of the stained part due to picotanine or the like, It may be recognized as a bluish color than before.

  An object of the present invention is to provide an endoscope system that can match the color of a stained portion when an addition method light source is used with the color of the stained portion when a broadband light source is used.

To achieve the above object, an endoscope system of the present invention includes blue light, green light, first red light, and second red light having a wavelength band longer than the first red light. Generates illumination light and controls the emission intensity ratio of the additive light source emitted from different light sources of the first red light and the second red light, and the blue light, green light, first red light, and second red light A light source controller that illuminates the observation target with an illumination light source, an image sensor that images the observation target and outputs a color image signal, and an observation image generator that processes the image signal to generate an observation image And a color of an observation target on an observation image obtained by illuminating with illumination light generated by an addition method light source, and at least in a wavelength band including green light, first red light, and second red light Image obtained by illuminating with broadband light having a strong emission intensity spectrum A light emission ratio setting unit that sets the light emission intensity ratio so that the color difference from the color of the observation target is a predetermined value or less, and the addition method light source includes a red light source that emits first red light, and a first red light A green light source that emits green light having a wavelength band that is longer than the peak wavelength of the light, a first threshold that exists between the peak wavelength of the first red light and the peak wavelength of the green light, and the first red light A second threshold existing in a wavelength band longer than the peak wavelength of the first wavelength, an optical path of a wavelength component having a wavelength shorter than the first threshold of green light, and a second wavelength longer than the first threshold of the first red light . the optical path of the wavelength components of shorter wavelength than the threshold value, has a light path integration unit that integrates the optical path of the wavelength components of the wavelength longer than the second threshold value of the green light, the second red light, a second threshold value of the green light It is a longer wavelength component.

  A pigment spraying unit that sprays pigments on the observation target is provided, and the observation target is stained with pioctanin sprayed by the pigment spraying unit.

  The addition method light source includes a first red light source that emits first red light and a second red light source that emits second red light. The second red light preferably has a wavelength band of 640 to 680 nm.

  The addition method light source may include a red light source, a green light source, and an optical path integration unit. The red light source emits first red light. The green light source emits green light having a wavelength band that is longer than the peak wavelength of the first red light. The optical path integrating unit includes a first threshold existing between a peak wavelength of the first red light and a peak wavelength of the green light, and a second threshold existing in a wavelength band longer than the peak wavelength of the first red light. An optical path of a wavelength component having a wavelength shorter than the first threshold value of green light, an optical path of a wavelength component having a wavelength longer than the first threshold value of the first red light, and a wavelength component having a wavelength longer than the second threshold value of green light Integrate the optical path of the wavelength component. The second red light is a wavelength component having a wavelength component longer than the second threshold value of green light.

  The green light source is composed of an excitation light source that emits excitation light and a phosphor that emits light upon receiving the excitation light. The optical path integrating unit is preferably a dichroic mirror. The second threshold value is preferably present in the wavelength band of 640 to 660 nm.

  The image signal includes a red image signal, a green image signal, and a blue image signal, and preferably includes a gain correction unit that performs gain correction on the red image signal in accordance with the emission intensity of the first red light. The gain amount with respect to the red image signal is larger as the emission intensity of the first red light is lower.

  It is preferable to provide an infrared cut filter that cuts infrared rays from the illumination light. This infrared cut filter cuts infrared rays having a wavelength longer than 670 nm.

  According to the present invention, it is possible to match the color of the dyed portion when the addition method light source is used with the color of the dyed portion when the broadband light source is used.

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 an addition system light source. It is a graph which shows each luminescence intensity spectrum of purple light, blue light, green light, 1st red light, and 2nd red light. It is a figure which shows the structure of G-LED. It is a graph which shows the optical characteristic of a 1st dichroic mirror. It is a graph which shows the optical characteristic of a 2nd dichroic mirror. It is a graph which shows the optical characteristic of a 3rd dichroic mirror. It is a graph which shows the optical characteristic of a 4th dichroic mirror. It is a graph which shows the optical characteristic of an infrared cut filter. (A) is a figure which shows the emission intensity spectrum of the illumination light of 1st Embodiment, (B) is a figure which shows the spectral reflection spectrum of a pigment | dye, (C) is the emission intensity spectrum of the illumination light of a broadband light source. FIG. It is a figure which shows the structure of the addition system light source of 2nd Embodiment. It is a graph which shows the optical characteristic of the 3rd dichroic mirror of 2nd Embodiment. (A) is a figure which shows the emission intensity spectrum of the illumination light of 2nd Embodiment, (B) is a figure which shows the spectral reflection spectrum of a pigment | dye, (C) is the emission intensity spectrum of the illumination light of a broadband light source. FIG. (A) is a graph showing the relationship between the emission intensity of the first red light and the color difference, and (B) is a diagram showing the relationship between the emission intensity of the first red light and the gain amount for the red image signal.

[First Embodiment]
In FIG. 1, the endoscope system 10 includes an endoscope 12, 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 by the universal cord 25.

  The endoscope 12 includes an insertion portion 12a to be inserted into the subject, an operation portion 12b provided at the proximal end portion of the insertion portion 12a, a bending portion 12c provided at the distal end side of the insertion portion 12a, and a bending portion. And a tip portion 12d provided at the tip of the portion 12c. By operating the angle knob 12e of the operation portion 12b, the bending portion 12c is bent. With this bending operation, the tip 12d is directed in a desired direction. In addition to the angle knob 12e, the operation unit 12b is provided with a zoom operation unit 13 and the like.

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

  The endoscope 12 is provided with a forceps channel 20. The forceps channel 20 is inserted with a spray tube 22 for spraying the pigment onto the observation target. The spray tube 22 is inserted into the forceps channel 20 from a forceps inlet 20a provided in the operation unit 12b. At least the distal end 22a of the spray tube 22 is exposed from a forceps outlet 20b formed at the distal end portion 12d of the endoscope 12.

  A syringe 24 filled with a coloring agent such as pioctane or indigo carmine is connected to the proximal end side of the spray tube 22. A user such as a doctor can spray the pigment in the form of a mist toward the observation target from the tip 22 a of the spray tube 22 by operating the syringe 24. The “pigment spraying portion” of the present invention corresponds to a configuration including the spray tube 22 and the syringe 24.

  In FIG. 2, the light source device 14 includes an addition method light source 30, a light source control unit 31, and a light emission ratio setting unit 32. The addition method light source 30 is driven by the light source control unit 31 to generate white illumination light. The light emitted from the addition method light source 30 is irradiated to the observation target in the subject through the light guide 33 and the illumination lens 35 inserted into the insertion portion 12a. The “illumination unit” of the present invention corresponds to a configuration including the light guide 33 and the illumination lens 35.

  The light guide 33 is incorporated in the endoscope 12 and the universal cord 25, and propagates the illumination light supplied from the addition method light source 30 to the distal end portion 12d of the endoscope 12. As the light guide 33, a multimode fiber can be used. As an example, a thin fiber cable having a core diameter of about 105 μm, a cladding diameter of about 125 μm, and a diameter including an outer skin (protective layer) of φ0.3 to 0.5 mm can be used.

  The distal end portion 12d of the endoscope 12 is provided with an illumination optical system 34a and an imaging optical system 34b. The illumination optical system 34 a has an illumination lens 35. The illumination light emitted from the light guide 33 is applied to the observation target via the illumination lens 35. The imaging optical system 34 b includes an objective lens 36, a zoom lens 37, and an imaging element 38. The return light from the observation target of the illumination light enters the image sensor 38 through the objective lens 36 and the zoom lens 37. An optical image to be observed is formed on the image sensor 38.

  The zoom lens 37 moves between the tele end and the wide end in accordance with the operation of the zoom operation unit 13. When magnification observation is not performed (during non-magnification observation), the zoom lens 37 is disposed at the wide end. When performing magnified observation, the zoom lens 37 moves from the wide end to the tele end in accordance with the operation of the zoom operation unit 13.

  The image sensor 38 is a simultaneous primary color sensor that captures a light image to be observed and outputs a color image signal. As the image sensor 38, a complementary metal-oxide semiconductor (CMOS) type image sensor is used.

  The imaging device 38 has a red (R) color filter having the first spectral transmission characteristic 38a, a green (G) color filter having the second spectral transmission characteristic 38b, and a blue having the third spectral transmission characteristic 38c shown in FIG. (B) a color filter. Each pixel of the image sensor 38 is provided with any one color filter. That is, the image sensor 38 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. Note that the B pixel has sensitivity to purple (V) light in addition to blue light.

  The image sensor 38 includes a correlated double sampling circuit and an A / D (Analog to Digital) converter, and outputs each image signal as a digital signal.

  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 observation image generation unit 44, and a video signal generation unit 45. The imaging control unit 40 controls the imaging timing of the observation target by the imaging element 38 and the output timing of the image signal from the imaging element 38.

  The receiving unit 41 receives a digital RGB image signal output from the imaging device 38 of 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 RGB image signal.

  In the defect correction process, the signal of the defective pixel of the image sensor 38 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 observation image generation unit 44.

  The observation image generation unit 44 generates an observation image by performing image processing such as color conversion processing, color enhancement processing, and structure enhancement processing on the RGB image signal input from the noise removal unit 43. 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 observation image generated by the observation image generation unit 44 is input to the video signal generation unit 45. The video signal generation unit 45 converts the observation image into a video signal for display on the monitor 18. The monitor 18 displays an image based on the video signal input from the video signal generation unit 45.

  In FIG. 4, the addition method light source 30 includes a V-LED 50a, a B-LED 50b, a G-LED 50c, an R1-LED 50d, an R2-LED 50e, an LED driving unit 51, and first to fifth collimator lenses 52a to 52a. 52e, first to fourth dichroic mirrors (DM) 55a to 55d, an infrared cut filter 56, and a condenser lens 59.

  The addition method light source 30 is an addition method light source that generates illumination light by adding light emitted from the light sources of the V-LED 50a, the B-LED 50b, the G-LED 50c, the R1-LED 50d, and the R2-LED 50e. In the present embodiment, the addition of light from the light source is performed by the first to fourth DMs 55a to 55d.

  As shown in FIG. 5, the V-LED 50a is a violet light source that emits violet light LV having a peak wavelength of about 405 nm and a wavelength band of about 380 to 420 nm. The B-LED 50b is a blue light source that emits blue light LB having a peak wavelength of about 460 nm and a wavelength band of about 420 to 480 nm. The G-LED 50c is a green light source that emits green light LG having a peak wavelength of about 530 nm and a wavelength band of about 480 to 700 nm. The R1-LED 50d is a first red light source that emits the first red light LR1 having a peak wavelength of about 630 nm and a wavelength band of about 600 to 650 nm. The R2-LED 50e is a second red light source that emits the second red light LR2 having a peak wavelength of about 660 nm and a wavelength band of about 640 to 680 nm. The second red light LR2 has a longer wavelength band than the first red light LR1.

  Among the V-LED 50a, B-LED 50b, G-LED 50c, R1-LED 50d, and R2-LED 50e, the G-LED 50c includes an excitation LED 61 as an excitation light source and a green phosphor 62 as shown in FIG. It consists of a combination. The excitation LED 61 generates excitation light LE having a peak wavelength of about 440 nm and makes it incident on the green phosphor 62. The green phosphor 62 emits light upon receiving the excitation light LE, and generates green light LG. Thus, since the G-LED 50c has the green phosphor 62, the wavelength band of the green light LG extends from the green region to the red region.

  The LED drive unit 51 drives the V-LED 50a, the B-LED 50b, the G-LED 50c, the R1-LED 50d, and the R2-LED 50e, respectively.

  The first to fifth collimator lenses 52a to 52e are arranged to correspond to the V-LED 50a, the B-LED 50b, the G-LED 50c, the R1-LED 50d, and the R2-LED 50e, respectively, and the purple light LV, the blue light LB, The green light LG, the first red light LR1, and the second red light LR2 are collimated. Hereinafter, the optical paths of the violet light LV, the blue light LB, the green light LG, the first red light LR1, and the second red light LR2 collimated by the first to fifth collimator lenses 52a to 52e, respectively, These are referred to as five optical paths 57a to 57e.

  The first optical path 57a and the second optical path 57b are orthogonal to each other, and the first DM 55a is disposed at this intersection. Specifically, the first DM 55a is arranged such that one surface intersects the first optical path 57a at an angle of 45 ° and the other surface intersects the second optical path 57b at an angle of 45 °. As shown in FIG. 7, the first DM 55a has a threshold T1 at about 425 nm, reflects light having a wavelength shorter than the threshold T1, and transmits light having a wavelength longer than the threshold T1. Here, the threshold T1 is a wavelength at which the light transmittance and light reflectance of the first DM 55a are approximately 50%. By having this optical characteristic, the first DM 55a reflects most of the purple light LV and transmits most of the blue light LB. Therefore, the first optical path 57a and the second optical path 57b are integrated by the first DM 55a. Hereinafter, the optical path in which the first optical path 57a and the second optical path 57b are integrated is referred to as a first integrated optical path 58a.

  The fourth optical path 57d and the fifth optical path 57e are orthogonal to each other, and the second DM 55b is disposed at this intersection. Specifically, the second DM 55b is arranged such that one surface intersects the fourth optical path 57d at an angle of 45 ° and the other surface intersects the fifth optical path 57e at an angle of 45 °. As shown in FIG. 8, the second DM 55b has a threshold T2 at about 640 nm, transmits light having a wavelength shorter than the threshold T2, and reflects light having a wavelength longer than the threshold T2. Here, the threshold value T2 is a wavelength at which the light transmittance and light reflectance of the second DM 55b are approximately 50%. By having this optical characteristic, the second DM 55b transmits most of the first red light LR1, and reflects most of the second red light LR2. Accordingly, the second optical path 57d and the optical path of the fifth optical path 57e are integrated by the second DM 55b. Hereinafter, the optical path in which the fourth optical path 57d and the fifth optical path 57e are integrated is referred to as a second integrated optical path 58b.

  The second integrated optical path 58b and the third optical path 57c are orthogonal to each other, and the third DM 55c is disposed at this intersection. Specifically, the third DM 55c is arranged so that one surface intersects the second integrated optical path 58b at an angle of 45 ° and the other surface intersects the third optical path 57c at an angle of 45 °. As shown in FIG. 9, the third DM 55c has a threshold T3 at about 590 nm, transmits light having a wavelength shorter than the threshold T3, and reflects light having a wavelength longer than the threshold T3. Here, the threshold T3 is a wavelength at which the light transmittance and light reflectance of the third DM 55c are approximately 50%. By having this optical characteristic, the third DM 55c transmits most of the green light LG and reflects most of the first red light LR1 and the second red light LR2. Therefore, the second integrated optical path 58b and the third optical path 57c are integrated by the third DM 55c. Hereinafter, the optical path in which the second integrated optical path 58b and the third optical path 57c are integrated is referred to as a third integrated optical path 58c.

  The first integrated optical path 58a and the third integrated optical path 58c are orthogonal to each other, and the fourth DM 55d is disposed at this intersection. Specifically, the fourth DM 55d is disposed so that one surface intersects the first integrated optical path 58a at an angle of 45 ° and the other surface intersects the third integrated optical path 58c at an angle of 45 °. As shown in FIG. 10, the fourth DM 55d has a threshold T4 at about 480 nm, reflects light having a wavelength shorter than the threshold T4, and transmits light having a wavelength longer than the threshold T4. Here, the threshold T4 is a wavelength at which the light transmittance and the light reflectance of the fourth DM 55d are approximately 50%. By having this optical characteristic, the fourth DM 55d transmits most of the green light LG, the first red light LR1, and the second red light LR2, and reflects most of the purple light LV and the blue light LB. Accordingly, the first integrated optical path 58a and the third integrated optical path 58c are integrated by the fourth DM 55d. Hereinafter, the optical path in which the first integrated optical path 58a and the third integrated optical path 58c are integrated is referred to as a fourth integrated optical path 58d.

  The infrared cut filter 56 is disposed on the fourth integrated optical path 58d. As shown in FIG. 11, the infrared cut filter 56 has a threshold value T5 of about 670 nm, transmits light having a wavelength shorter than the threshold value T5, and reflects light having a wavelength longer than the threshold value T5, thereby being larger than the threshold value T5. Cuts light of wavelength (infrared). Here, the threshold value T5 is a wavelength at which the light transmittance and light reflectance of the infrared cut filter 56 are approximately 50%.

  The condensing lens 59 is disposed in the vicinity of the incident end of the light guide 33, condenses the light transmitted through the infrared cut filter 56, and makes it incident on the incident end of the light guide 33 as illumination light. This illumination light is emitted from the distal end portion 12d of the endoscope 12 and illuminates the observation target.

  The LED driving unit 51 is controlled by the light source control unit 31. The light emission ratio setting unit 32 stores a light emission intensity ratio setting value for each of the LEDs 50a to 50e. The light source control unit 31 adjusts the light emission intensity of each of the LEDs 50 a to 50 e by driving the LED driving unit 51 based on the set value of the light emission intensity ratio stored in the light emission ratio setting unit 32.

  The set value stored in the light emission ratio setting unit 32 is set based on the color on the observation image of the observation target in which the picotanine is dispersed. Specifically, in the light emission ratio setting unit 32, when pioctanin is scattered on the observation target, the color of the stained portion illuminated by the illumination light generated by the addition method light source 30 of the present embodiment, and the conventional Stored is a set value for setting the color difference with the color of the stained portion obtained by illumination light (broadband light) generated by the wide-band light source to a certain value or less. This color difference is represented by a distance ΔE in the Lab space. For example, a set value is determined so as to satisfy ΔE ≦ 6. The broadband light generated by the conventional broadband light source has a continuous emission intensity spectrum in a wavelength band including at least the green light LG, the first red light LR1, and the second red light LR2.

  The illumination light generated by the addition method light source 30 of the present embodiment has a light emission intensity spectrum as shown in FIG. FIG. 12B shows a spectral reflection spectrum RS1 of pioctane and a spectral reflection spectrum RS2 of indigo carmine. Pioctanin has a certain reflectance in a wavelength band of about 470 nm or less and a wavelength band of about 640 nm or more. Indigo carmine has a certain reflectance in a wavelength band of about 520 nm or less and a wavelength band of about 670 nm or more.

  FIG. 12C shows an emission intensity spectrum of illumination light generated by a xenon light source, for example, as broadband light generated by a conventional broadband light source. This illumination light has a continuous emission intensity spectrum from about 400 nm to about 670 nm.

  Since the conventional addition-type light source does not have the second red light source that emits the second red light LR2 as in this embodiment, the upper limit wavelength of the wavelength spectrum is about 650 nm. For this reason, the return light from the stained part with pioctane in the observation target hardly contains a red component larger than about 650 nm, and the stained part is displayed in the observation image as a color close to blue. On the other hand, since the addition method light source 30 of the present embodiment has the R2-LED 50e as the second red light source, the return light from the dyeing portion with pioctane contains a lot of red components larger than about 650 nm, The dyed portion is displayed in the observation image as bluish violet as in the case of using illumination light of a conventional broadband light source (see FIG. 12C).

  On the other hand, indigo carmine has a reflectance of a certain level or more in a wavelength band of about 670 nm or more, and if the illumination light contains a lot of wavelength components of about 670 nm or more, it is caused by indigo carmine in the observation target. The color of the stained part is displayed in the observation image with a reddish tint. In the present embodiment, since the wavelength component of about 670 nm or more is cut from the illumination light by the infrared cut filter 56, the stained portion by indigo carmine uses the illumination light of the conventional broadband light source (see FIG. 12C). As in the case of using it, it is displayed in the observation image as blue.

  Next, the operation of the endoscope system 10 of the present embodiment will be described. First, a user such as a doctor conducts a distant view observation in the subject and performs screening in a state where the insertion portion 12a of the endoscope 12 is inserted into the subject such as the large intestine. At this time, a light emission operation of the light source device 14, an imaging operation by the imaging device 38 in the endoscope 12, an observation image generation operation by the processor device 16, and an image display operation of the observation image on the monitor 18 are performed.

  In the light source device 14, the light source control unit 31 controls the light emission intensity of each LED 50 a to 50 e of the addition method light source 30 by driving the LED driving unit 51 based on the setting value stored in the light emission ratio setting unit 32. . Lights emitted from the LEDs 50a to 50e (purple light LV, blue light LB, green light LG, first red light LR1, and second red light LR2) are combined by the first to fourth DMs 55a to 55d to cut infrared rays. By passing through the filter 56, it becomes illumination light having the emission intensity spectrum shown in FIG. The illumination light is collected by the condenser lens 59 and enters the light guide 33 in the endoscope 12, and is emitted from the distal end portion 12 d of the endoscope 12 to illuminate the observation target.

  The observation object illuminated by the illumination light is imaged by the image sensor 38 in the endoscope 12. The image sensor 38 generates digital RGB image signals and inputs them to the processor device 16. In the processor device 16, the RGB image signal is subjected to various signal processing by the DSP 42, subjected to noise removal processing by the noise removal unit 43, and input to the observation image generation unit 44. The observation image generation unit 44 generates an observation image by performing various image processing on the input RGB image signal. The observation image is displayed on the monitor 18 via the video signal generation unit 45. This observation image is displayed in red. This is because hemoglobin in the observation target absorbs shortwave light.

  When the user detects a possible lesion (such as a possible lesion) such as a brownish area or redness during screening, the user operates the zoom operation unit 13 to enlarge the observation target including the likely lesion. Perform magnified observation. In addition, the user disperses the pigment on the observation target in order to clarify the possible lesion site. Specifically, in the enlarged observation image, the user confirms the tip 22a of the spray tube 22 and then operates the syringe 24 filled with a coloring agent such as pioctane or indigo carmine to thereby obtain the coloring matter. Is sprayed on the observation target.

  The light emission operation, the imaging operation, the observation image generation operation, and the image display operation in this magnified observation are the same as in the distant view observation. On the monitor 18, an observation image including a lesion portion stained with the dispersed pigment is displayed. In the present embodiment, as described above, since the illumination light includes a wavelength component of about 650 to 670 nm, the stained portion by pioctane and the stained portion by indigo carmine in the observation target are respectively illumination lights of conventional broadband light sources. Is displayed in the observation image as the same color as when using.

  Thus, the color of the stained portion observed by the endoscope system 10 of the present embodiment has a small difference (color difference) from the color of the stained portion observed by the endoscope system having a conventional broadband light source, Even users who are used to observation with an endoscope system having a conventional broadband light source do not feel a change in color.

  In the first embodiment, the optical characteristics shown in FIGS. 7 to 10 are used as the optical characteristics of the first to fourth DMs 55a to 55d. However, the present invention is not limited to this, and the relationship between transmission and reflection of each optical characteristic is used. The reverse can also be used.

[Second Embodiment]
In the first embodiment, the second red light source (R2-LED 50e) is provided in order to obtain the second red light LR2. In the second embodiment, a green light source (not provided with the second red light source) is provided. The second red light LR2 is obtained by extracting the long wavelength component (wavelength component on the longer wavelength side from about 650 nm) of the green light emitted from the G-LED 50c).

  That is, in the first embodiment, by providing the first red light source (R1-LED 50d) and the second red light source (R2-LED 50e), the second red light LR2 is emitted different from the first red light LR1. In the second embodiment, the second red light LR2 is extracted from the green light source (G-LED 50c) so that the second red light LR2 is different from the first red light LR1. Generate from.

  In the second embodiment, an addition method light source 60 shown in FIG. 13 is used instead of the addition method light source 30 of the first embodiment. The addition method light source 60 removes the R2-LED 50e, the fifth collimator lens 52e, and the second DM 55b from the addition method light source 30 of the first embodiment, and the third DM 55c has the optical characteristics shown in FIG. .

  In the present embodiment, the third DM 55c has a first threshold T3A at about 590 nm and a second threshold T3B at about 650 nm. The third DM 55c transmits light having a wavelength shorter than the first threshold T3A, and reflects light having a wavelength longer than the first threshold T3A and shorter than the second threshold T3B. The third DM 55c transmits light having a wavelength longer than the second threshold T3B.

  Since most of the wavelength component of the first red light LR1 emitted from the R1-LED 50d as the red light source exists in the wavelength band between the first threshold T3A and the second threshold T3B of the third DM 55c, the third DM 55c It is reflected by. On the other hand, since the green light LG emitted from the G-LED 50c has a wide wavelength band and spreads from the green region to the longer wavelength side than the peak wavelength (about 630 nm) of the first red light LR1, the first threshold T3A. A short wavelength component transmits through the third DM 55c, and a wavelength component longer than the second threshold T3B transmits through the third DM 55c. In the present embodiment, the wavelength component longer than the second threshold value T3B in the green light LG is the second red light LR2.

  The third DM 55c corresponds to the “optical path integration unit” of the present invention. That is, the third DM 55c has an optical path with a wavelength component shorter than the first threshold T3A of the green light LG, an optical path with a wavelength component longer than the first threshold T3A of the first red light LR1, and the second path of the green light LG. The optical path of the wavelength component (second red light LR2) having a wavelength longer than the threshold T3B is integrated. The first threshold value T3A exists between the peak wavelength of the first red light LR1 and the peak wavelength of the green light LG. The second threshold T3B is preferably present in a wavelength band (640 to 660 nm) longer than the peak wavelength of the first red light LR1.

  In the present embodiment, the first red light LR1, the green light LG (wavelength component shorter than the first threshold T3A), and the second red light LR2 are combined and incident on the fourth DM 55d by the third DM 55c. The wavelength component longer than about 670 nm of the second red light LR2 is cut by the infrared cut filter 56.

  The illumination light generated by the addition method light source 60 of the present embodiment has a light emission intensity spectrum as shown in FIG. The light quantity of the second red light LR2 is larger than the light quantity of the wavelength component longer than about 670 nm in the first red light LR1. However, the light quantity of the second red light LR2 is about several percent of the total light quantity of the green light LG emitted from the G-LED 50c, and is smaller than the light quantity of the first red light LR1.

  For this reason, when pioctanin is scattered on the observation target, the color of the stained portion illuminated by the illumination light generated by the addition method light source 60 of this embodiment and the illumination light generated by the conventional broadband light source ( In order to make the color difference from the color of the stained portion obtained by the broadband light) below a certain value, the emission intensity of the first red light LR1 by the R1-LED 50d is decreased, and the light quantity of the first red light LR1 and the second red light It is necessary to reduce the difference from the light amount of the light LR2. As described above, when the emission intensity of the first red light LR1 is reduced, the total red light amount of the first red light LR1 and the second red light LR2 is reduced, so that the DSP 42 performs gain correction on the red image signal. It is preferable to carry out. The DSP 42 corresponds to the “gain correction unit” of the present invention.

  As shown in FIG. 16A, the color difference decreases the light emission intensity of the first red light LR1, and decreases as the light amount of the first red light LR1 decreases. However, if the light amount of the first red light LR1 is excessively reduced, the S / N of the red image signal is reduced, so that the color difference of the first red light LR1 becomes a predetermined value α (for example, ΔE = 6). It is preferable to set the emission intensity. This set value of the emission intensity is referred to as β. The set value β is stored in the light emission ratio setting unit 32 together with the set values of the light emission intensities of the V-LED 50a, the B-LED 50b, and the G-LED 50c.

  As shown in FIG. 16B, the gain amount for the red image signal is set based on the set value β. A gain amount corresponding to the set value β is γ. The gain amount γ increases as the emission intensity of the first red light LR1 decreases. The DSP 42 performs gain correction of the red image signal using the gain amount γ corresponding to the set value β stored in the light emission ratio setting unit 32.

  As described above, in the second embodiment, since the second red light LR2 can be generated without providing the second red light source, the light source device can be reduced in size.

  The color of the stained portion observed by the endoscope system of the present embodiment has a small difference (color difference) from the color of the stained portion observed by the endoscope system having the conventional broadband light source. Even users who are accustomed to observing with the endoscope system they do not feel a change in color.

  In the second embodiment, the light intensity of the first red light LR1 and the light intensity of the first red light LR1 are reduced by reducing the emission intensity of the first red light LR1 by the R1-LED 50d, thereby reducing the light quantity of the first red light LR1 and the second red light LR2. The difference with the light amount is reduced, but instead, the light intensity of the first red light LR1 is increased by increasing the light intensity of the green light LG by the G-LED 50c and increasing the light amount of the second red light LR2. It is also possible to reduce the difference from the light amount of the second red light LR2.

  Moreover, in the said 2nd Embodiment, although what is shown in FIG.7, FIG.8 and FIG.14 is used as an optical characteristic of 1st-3rd DM55a-55c, it is not restricted to this, Transmission of each optical characteristic and It is also possible to use a reverse reflection relationship.

  In the first and second embodiments, the infrared cut filter 56 is disposed between the fourth DM 55d and the condensing lens 59, but may be disposed between the third DM 55c and the fourth DM 55d. Further, the infrared cut filter 56 can be omitted by incorporating the optical characteristics of the infrared cut filter 56 into the optical characteristics of the third DM 55c or the fourth DM 55d.

  Moreover, in the said 1st and 2nd embodiment, although V-LED50a as a purple light source is provided in the addition system light sources 30 and 60, this purple light source is not essential. Therefore, the violet light source is not provided, and the addition method light source may be configured by a blue light source, a green light source, a first red light source, and a second red light source.

  Moreover, in the said 1st and 2nd embodiment, although the infrared cut filter 56 is provided, the illumination light produced | generated by the addition system light sources 30 and 60 is compared with the illumination light produced | generated by the conventional broadband light source, Since there are few wavelength components larger than the threshold T5 of about 670 nm, the infrared cut filter 56 is not essential and may be provided as necessary.

  In the first and second embodiments, a primary color sensor is used as the image sensor 38, but a complementary color sensor may be used instead. This complementary color sensor preferably has a cyan (C) pixel, a magenta (Mg) pixel, a yellow (Y) pixel, and a green (G) pixel. As described above, when the image sensor 38 is a complementary color sensor, the processor device 16 may perform an operation for converting a complementary color image signal (CMYG image signal) into a primary color image signal (RGB image signal).

  In the first and second embodiments, a CMOS type image sensor is used as the image sensor 38, but a CCD (Charge-Coupled Device) type image sensor may be used instead.

  In the first and second embodiments, a xenon light source, which is a kind of high-intensity discharge light source, is used as a conventional broadband light source to be compared with the addition method light source of the present invention. Other broadband light sources may be used as long as they have a continuous emission intensity spectrum including the wavelength bands of the first red light LR1 and the second red light LR2. For example, you may use the broadband light source described in Unexamined-Japanese-Patent No. 2014-121630. This broadband light source has a laser light source that emits blue laser light having a center wavelength of about 445 nm, and a phosphor that emits white fluorescence in response to the blue laser light.

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

DESCRIPTION OF SYMBOLS 10 Endoscope system 12 Endoscope 14 Light source apparatus 16 Processor apparatus 20 Forceps channel 22 Spreading tube 22a Tip 24 Syringe 30,60 Addition system light source 55a-55d 1st-4th dichroic mirror 56 Infrared cut filter

Claims (9)

Illumination light including blue light, green light, first red light, and second red light having a longer wavelength band than the first red light is generated, and the first red light and the second red light are generated. An additive light source emitted from a light source different from the light;
A light source controller that controls a light emission intensity ratio of the blue light, the green light, the first red light, and the second red light;
An illumination unit for irradiating the observation target with the illumination light;
An imaging device that images the observation target and outputs a color image signal;
An observation image generation unit that performs image processing on the image signal to generate an observation image;
A wavelength including the color of the observation target on the observation image obtained by illuminating with the illumination light generated by the addition method light source, and at least the green light, the first red light, and the second red light A light emission ratio setting unit for setting the light emission intensity ratio so that a color difference with the color of the observation object on the observation image obtained by illuminating with broadband light having a continuous light emission intensity spectrum in a band is set to a predetermined value or less. When,
With
The additive light source is
A red light source emitting the first red light;
A green light source that emits the green light having a wavelength band that is longer than the peak wavelength of the first red light;
A first threshold existing between a peak wavelength of the first red light and a peak wavelength of the green light, and a second threshold existing in a wavelength band longer than the peak wavelength of the first red light. , An optical path of a wavelength component having a wavelength shorter than the first threshold of the green light, an optical path of a wavelength component having a wavelength longer than the first threshold and a wavelength shorter than the second threshold of the first red light, and the green light An optical path integrating unit that integrates an optical path of a wavelength component having a wavelength longer than the second threshold;
Have
The endoscope system, wherein the second red light is a wavelength component having a wavelength longer than the second threshold value of the green light. A pigment spraying unit for spraying the pigment on the observation target;
The endoscope system according to claim 1, wherein the observation object is stained with pioctanine sprayed by the pigment spraying unit. The green light source, the excitation light source and the endoscope system according to claim 1 or 2 is constituted by a phosphor emitting receiving said excitation light to emit excitation light. The endoscope system according to any one of claims 1 to 3 , wherein the optical path integrating unit is a dichroic mirror. The endoscope system according to any one of claims 1 to 4 , wherein the second threshold value exists in a wavelength band of 640 to 660 nm. The image signal comprises a red image signal, a green image signal, and a blue image signal,
The endoscope system according to any one of claims 1 to 5 , further comprising a gain correction unit that performs gain correction on the red image signal in accordance with a light emission intensity of the first red light. The endoscope system according to claim 6 , wherein the gain amount with respect to the red image signal is larger as the emission intensity of the first red light is lower. The endoscope system according to any one of claims 1 to 7, further comprising an infrared cut filter that cuts infrared light from the illumination light. The endoscope system according to claim 8 , wherein the infrared cut filter cuts infrared rays having a wavelength longer than 670 nm.

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