JP2016032494A - Endoscope system, operation method for endoscope system, light source apparatus, and operation method for light source apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope system, an operation method for the endoscope system, a light source apparatus, and an operation method for the light source apparatus capable of preventing occurrence of color mixture when an image of the interior of a subject simultaneously irradiated with a plurality of light beams of different colors is captured by a color imaging device.SOLUTION: An endoscope system 10 has a normal mode and a high picture quality mode. In the high picture quality mode, a light-emitting element control unit 22 controls the switching between a first light emission mode in which blue limit light LBs and red light LR are emitted and a second light emission mode in which violet light LV and green light LG are emitted. An imaging device 36 images an observation target 24 illuminated in the first light emission mode to output a first blue image signal and a first red image signal. The imaging device 36 images the observation target 24 illuminated in the second light emission mode to output a second blue image signal and a second green image signal. A high picture quality image generation unit 56 generates a high picture quality image from the first blue image signal, first red image signal, second blue image signal, and second green image signal.SELECTED DRAWING: Figure 12

Description

  The present invention relates to an endoscope system, a method for operating an endoscope system, a light source device, and a method for operating a light source device that can prevent color mixing in a color image sensor using a plurality of semiconductor light sources such as LEDs.

  In recent medical treatment, diagnosis using an endoscope system including an endoscope light source device (hereinafter referred to as a light source device), an electronic endoscope (hereinafter referred to as an endoscope), and a processor device is widely performed. ing. The light source device generates illumination light for illuminating the inside of the subject. The endoscope includes an image sensor and images an inside of a subject illuminated with illumination light to generate an image signal. The processor device performs image processing on the image signal transmitted from the endoscope and generates an image to be displayed on the monitor.

  Conventionally, a light source device is a white light source (see Patent Document 1) such as a xenon lamp or a white LED (Light Emitting Diode), an LD (Laser Diode), and a fluorescent light that is excited by light emitted from the LD and emits fluorescence. A white light source (see Patent Document 2) combined with a body is used. On the other hand, in recent years, semiconductor light sources that emit light by freely combining light of each color by independently controlling light emitting elements such as a blue LED that emits blue light, a green LED that emits green light, and a red LED that emits red light. (See Patent Document 3) is being used. Compared with a white light source, the semiconductor light source has an advantage that illumination light having various hues can be freely generated by independently controlling the amount of light of each color.

  The imaging device provided in the endoscope has a blue pixel provided with a blue (B) filter, a green pixel provided with a green (G) filter, and a red pixel provided with a red (R) filter. An element (hereinafter referred to as a color imaging element) is generally used (see Patent Documents 1 to 3). The blue pixel is sensitive to blue light, and receives blue light return light to generate a blue image signal. The green pixel is sensitive to green light, and receives green return light to generate a green image signal. The red pixel is sensitive to red light, and receives red return light to generate a red image signal.

JP 2014-050458 A JP 2012-125501 A Japanese Patent No. 5393446

  Here, when light of a plurality of colors whose wavelength bands are adjacent to each other is emitted at the same time, when imaging is performed with a color imaging device, one color pixel receives light of two or more colors, and so-called color mixing occurs. . For example, when blue light and green light whose wavelength bands are adjacent to each other are simultaneously emitted, the green pixel receives both blue light and green light, and color mixing occurs. Therefore, a green image signal in which blue light information and green light information are mixed is generated from the green pixel. When such color mixture occurs, there is a problem that the color reproducibility of the image displayed on the monitor deteriorates.

  Regarding this problem, Patent Document 3 out of Patent Documents 1 to 3 describes correcting the color mixture state of the image signal by performing a color mixture correction process for correcting the color mixture state of the image signal. However, the color mixture correction processing described in Patent Document 3 performs an operation on an image signal output in a state where color mixture has occurred (that is, an image signal affected by the color mixture). It is not a fundamental prevention.

  The present invention relates to an endoscope system and an operation method of the endoscope system that can prevent the occurrence of color mixing even when a color imaging element is used to capture an image of a subject irradiated with a plurality of colors of light simultaneously. An object of the present invention is to provide a light source device and a method for operating the light source device.

  In order to achieve the above object, an endoscope system of the present invention includes a blue light emitting element that emits blue light, a red light emitting element that emits red light, a green light emitting element that emits broadband green light, and blue light and red light. Control for switching the first light emitting mode and the second light emitting mode by controlling the blue light emitting element, the red light emitting element, and the green light emitting element in the first light emitting mode for emitting light and the second light emitting mode for emitting green light. A light-emitting element controller that performs blue light, a blue pixel that is sensitive to blue light, a red pixel that is sensitive to red light, a sensitivity to green light, and at least one of blue light and red light. A color image sensor provided with a green pixel having sensitivity, and imaging for imaging a subject under illumination in the first light emission mode, and imaging the subject under illumination in the second light emission mode and outputting an image signal Control unit and image signal And an image processing unit that generates et specific image.

  The operating method of the endoscope system of the present invention includes a step in which a blue light emitting element emits blue light, a step in which a red light emitting element emits red light, a step in which a green light emitting element emits broadband green light, The light emitting element control unit controls the blue light emitting element, the red light emitting element, and the green light emitting element in a first light emitting mode that emits blue light and red light and a second light emitting mode that emits green light. The step of switching between the mode and the second light emission mode, and the imaging control unit has a blue pixel having sensitivity to blue light, a red pixel having sensitivity to red light, sensitivity to green light, and further, blue light and red By controlling a color imaging device provided with a green pixel that is sensitive to at least one of the lights, the subject being illuminated is imaged in the first emission mode and is being illuminated in the second emission mode Subject Comprising a step of outputting an image signal by capturing an image processing unit, and generating a specific image from the image signal.

  The light source device of the present invention is an endoscope light source device that supplies light to an endoscope having a color imaging device provided with blue pixels, red pixels, and green pixels. A blue light emitting element that emits blue light having sensitivity, a red light emitting element that emits red light having sensitivity to red pixels, and a sensitivity to green pixels, and at least one of blue pixels and red pixels A blue light emitting element and a red light emitting element in a green light emitting element that emits broadband green light having sensitivity to the pixels, a first light emitting mode that emits blue light and red light, and a second light emitting mode that emits green light. A light emitting element control unit that controls the element and the green light emitting element and performs control to switch between the first light emitting mode and the second light emitting mode;

  The operating method of the light source device according to the present invention is an operating method of the light source device for an endoscope that supplies light to an endoscope having a color imaging device provided with blue pixels, red pixels, and green pixels. The blue light emitting element emits blue light sensitive to the blue pixel, the red light emitting element emits red light sensitive to the red pixel, and the green light emitting element emits red light to the green pixel. A step of emitting broadband green light having sensitivity to at least one of the blue pixel and the red pixel, and a light emitting element control unit for emitting blue light and red light. Controlling the blue light emitting element, the red light emitting element, and the green light emitting element in the light emitting mode and the second light emitting mode for emitting green light, and switching between the first light emitting mode and the second light emitting mode.

  It is preferable that the light emitting device further includes a purple light emitting element that emits purple light, and the blue pixel is sensitive to blue light and purple light.

  The light emitting element control unit may control the purple light emitting element and the green light emitting element so as to emit purple light and green light in the second light emission mode.

  The imaging control unit outputs an image signal corresponding to each color pixel, and the image processing unit outputs the first blue image signal output from the blue pixel in the first light emission mode and the blue pixel in the second light emission mode. A signal adding unit for obtaining an added blue image signal obtained by weighting and adding the second blue image signal, the added blue image signal, the first red image signal output from the red pixel in the first light emission mode, and the second light emission. It is preferable to include an image generation unit that generates a specific image from the second green image signal output from the green pixel in the mode. Moreover, it is preferable that a signal addition part makes the weighting of a 2nd blue image signal larger than the weighting of a 1st blue image signal.

  The light emitting element control unit may control the purple light emitting element, the blue light emitting element, and the red light emitting element so as to emit purple light, blue light, and red light in the first light emission mode.

  The imaging control unit outputs an image signal corresponding to each color pixel, and the image processing unit outputs the first blue image signal output from the blue pixel in the first light emission mode and the red pixel in the first light emission mode. It is preferable to include an image generation unit that generates a specific image from the first red image signal and the second green image signal output from the green pixel in the second light emission mode.

  In the first light emission mode, the light emitting element control unit emits violet light with a light amount PV1, emits blue light with a light amount PB1, emits green light with a light amount PG1, emits red light with a light amount PR1, and In the two emission mode, violet light is emitted with the amount of light PV2, blue light is emitted with the amount of light PB2, green light is emitted with the amount of light PG2, red light is emitted with the amount of light PR2, and in the first emission mode, the amount of light PB1 is emitted. Is larger than the light amount PB2, the light amount PR1 is larger than the light amount PR2, the light amount PV1 is smaller than the light amount PV2, the light amount PG1 is smaller than the light amount PG2, and in the second light emission mode, the light amount PV2 is changed to the light amount PV1. The light quantity PG2 is larger than the light quantity PG1, the light quantity PB2 is smaller than the light quantity PB1, and the light quantity PR2 is smaller than the light quantity PR1. It may control the color light-emitting element and a blue light emitting element and the green light emitting element and the red light emitting element.

  In the first light emission mode, the light emitting element control unit emits violet light with a light amount PV1, emits blue light with a light amount PB1, emits green light with a light amount PG1, emits red light with a light amount PR1, and In the two light emission mode, violet light is emitted with the light amount PV2, blue light is emitted with the light amount PB2, green light is emitted with the light amount PG2, red light is emitted with the light amount PR2, and in the first light emission mode, the light amount PV1. Is larger than the light amount PV2, the light amount PB1 is larger than the light amount PB2, the light amount PR1 is larger than the light amount PR2, the light amount PG1 is smaller than the light amount PG2, and in the second light emission mode, the light amount PG2 is changed to the light amount PG1. So that the light amount PV2 is smaller than the light amount PV1, the light amount PB2 is smaller than the light amount PB1, and the light amount PR2 is smaller than the light amount PR1. It may control the light emitting element and a blue light emitting element and the green light emitting element and the red light emitting element.

  Of the image signal output in the first light emission mode and the image signal output in the second light emission mode, the amount of positional deviation between the image signals output by imaging the subject illuminated with the same color light is calculated. A misregistration amount calculation unit to calculate, and an alignment unit that performs alignment between the image signal output in the first light emission mode and the image signal output in the second light emission mode based on the misregistration amount. It is preferable to provide.

  It is preferable to have an attenuation filter that attenuates light of a specific wavelength within the range of 460 nm to 500 nm on the optical path of the blue light emitting element.

  The light emitting element control unit may sequentially emit light from each color light emitting element in the first light emitting mode and the second light emitting mode. Further, the light emitting element control unit may simultaneously emit light from each color light emitting element.

  According to the present invention, in a first light emission mode in which blue light and red light whose wavelength bands are separated from each other are emitted, a subject under illumination is imaged with a color imaging device, and in a second light emission mode in which green light is emitted. Endoscope system capable of preventing color mixing by imaging a subject under illumination with a color imaging device and outputting an image signal, operation method of the endoscope system, light source device, operation of the light source device A method can be provided.

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 graph which shows the spectrum of the light which each color light emitting element light-emits. It is explanatory drawing which shows the penetration depth to the observation object of purple light, blue light, and green light. It is a graph which shows the spectrum spectrum of blue limited light. It is a graph which shows the spectrum of normal light. It is a graph which shows the spectrum of blue limited light and red light with which it is irradiated in the first emission mode. It is a graph which shows the spectrum of purple light and green light irradiated by 2nd light emission mode. It is a figure which shows the structure of a color filter array. It is a figure which shows the permeation | transmission characteristic of a color filter. It is explanatory drawing explaining the production | generation of an addition blue image signal. It is a flowchart explaining the effect | action of this invention. It is a graph which shows the spectrum of purple light, blue limited light, and red light irradiated in the 1st light emission mode of 2nd Embodiment. It is a graph which shows the spectrum of the green light irradiated by the 2nd light emission mode of 2nd Embodiment. It is a graph which shows the spectrum of the purple light, the blue limited light, the green light, and the red light irradiated in the first light emission mode of the third embodiment. It is a graph which shows the spectrum of purple light, blue limited light, green light, and red light irradiated in the 2nd light emission mode of 3rd Embodiment. It is a block diagram which shows the function of the high quality image generation part of 3rd Embodiment. It is explanatory drawing explaining the position shift correction between the frames of 3rd Embodiment. It is a graph which shows the spectrum of the purple light, the blue limited light, the green light, and the red light irradiated in the first light emission mode of the fourth embodiment. It is a graph which shows the spectrum of purple light, blue limited light, green light, and red light irradiated in the 2nd light emission mode of 4th Embodiment. It is explanatory drawing explaining the position shift correction between the frames of 4th Embodiment. It is explanatory drawing explaining the example which outputs an image signal after the imaging of 1st light emission mode and 2nd light emission mode.

[First Embodiment]
As shown 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. 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 changeover switch (hereinafter referred to as a mode changeover SW) 13. The mode switching SW 13 is used for an observation mode switching operation. The endoscope system 10 has a normal mode and a high image quality mode as observation modes. In the normal mode, an image having a natural color obtained by imaging the return light of white light (hereinafter referred to as a normal image) is displayed on the monitor 18. In the high image quality mode, a high quality image (specific image) with a higher image quality than the normal image is displayed on the monitor 18.

  The processor device 16 is electrically connected to the monitor 18 and the console 19. The monitor 18 displays images in each observation mode, image information attached to the images, and the like. 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, image information, and the like.

  As shown in FIG. 2, the light source device 14 includes a light source unit 20 that generates illumination light to be irradiated on an observation target, an attenuation filter 21 that attenuates light of a specific wavelength, and a light emitting element control that controls driving of the light source unit 20. And an optical path coupling unit 23 that couples optical paths of light generated by the light source unit 20 and the attenuation filter 21.

  The light source unit 20 includes a V-LED (Violet Light Emitting Diode) 20a, a B-LED (Blue Light Emitting Diode) 20b, a G-LED (Green Light Emitting Diode) 20c, and an R-LED (Red Light Emitting Diode) 20d. It has 4 color LEDs.

  As shown in FIG. 3, the V-LED 20a is a violet light emitting element that emits violet light LV having a center wavelength of 405 nm and a wavelength band of 380 nm to 420 nm. The B-LED 20b is a blue light emitting element that emits blue light LB having a center wavelength of 460 nm and a wavelength band of 420 nm to 500 nm. The G-LED 20c is a green light emitting element that emits broadband green light LG having a wavelength band ranging from 480 nm to 600 nm. The R-LED 20d is a red light emitting element that emits red light LR with a center wavelength of 620 nm to 630 nm, a wavelength band of 600 nm to 650 nm, and the like. The center wavelengths of the V-LED 20a and the B-LED 20b have a width of about ± 5 nm to ± 10 nm.

  The purple light LV and the blue light LB are light that is largely absorbed by hemoglobin on the surface layer of the living tissue and is reflected without being diffused in the living tissue around the blood vessel. The green light LG is light that diffuses deeper in the living tissue than the violet light LV and the blue light LB, and is much absorbed by hemoglobin.

  Here, as shown in FIG. 4, the penetration depth of the light to the observation object 24 changes depending on the color (wavelength), and the penetration depth is deeper as the wavelength is longer. The depth of penetration indicates the degree to which light reaches the depth direction from the mucous membrane of the observation target 24. Depending on the depth from the mucous membrane, it is referred to as a surface layer, a middle layer, and a deep layer, and a portion of the surface layer that is particularly shallow and close to the mucosa is referred to as an extreme surface layer. Blood vessels are also present in the mucous membrane, but are present at a depth below the surface layer (and the extreme surface layer). A deeper blood vessel tends to be observed as it is deeper than the mucous membrane. For example, the surface blood vessel 25 distributed from the extreme surface layer to the surface layer has the smallest diameter, the surface layer blood vessel 26 distributed near the surface layer is thicker than the surface blood vessel 25, and the middle layer blood vessel 27 distributed near the middle layer has a further diameter. thick. As the blood vessel becomes thicker, the blood volume increases, so that a larger amount of hemoglobin is contained.

  For example, when the observation object 24 is irradiated with the purple light LV, the blue light LB, and the green light LG, the purple light LV reaches from the extreme surface layer to the surface layer, and the blue light LB reaches the surface layer. The green light LG reaches the middle level. Therefore, the return light of the purple light LV mainly includes information on the mucous membrane and the polar surface blood vessel, and the return light of the blue light LB mainly includes information on the mucous membrane, the polar surface blood vessel, and the surface blood vessel. The return light of LG mainly includes information on mucous membranes and middle layer blood vessels.

  As shown in FIG. 5, the attenuation filter 21 is provided on the optical path of the B-LED 20b, and transmits light in the short wavelength side wavelength band (wavelength band of less than 460 nm) of the blue light LB emitted from the B-LED 20b. Then, the light in the wavelength band on the long wavelength side (the wavelength band is in the range of 460 nm to 500 nm) is attenuated. That is, the attenuation filter 21 generates blue light (hereinafter referred to as blue limited light) LBs obtained by band limiting the blue light LB to a specific wavelength. This is because it is known that the blue-color limited light LBs is generated from the blue light LB by the attenuation filter 21 so that the blood vessel contrast is improved.

  The attenuation filter 21 typically attenuates the blue light LB at a wavelength of 460 nm, but the actual attenuation characteristic has a width of about 5 nm to 10 nm. For this reason, the attenuation filter 21 has a characteristic that the transmittance is attenuated from around the wavelength of 450 nm in order to attenuate the light having a wavelength of 460 nm or more.

  The light emitting element control unit 22 adjusts the light emission timing, the light emission period, the light quantity, and the spectral spectrum of each color light by independently controlling the lighting / extinction of each LED 20a to 20d and the light quantity at the time of lighting.

  Specifically, as shown in FIG. 6, in the normal mode, all of the V-LED 20a, the B-LED 20b, the G-LED 20c, and the R-LED 20d are turned on, so that the purple light LV, the blue limited light LBs, and the green light are emitted. LG and red light LR are emitted simultaneously. As a result, in the normal mode, the purple light LV, the blue limited light LBs, the green light LG, and the red light LR are combined by the optical path combining unit 23 and irradiated onto the observation target 24. The normal light composed of the purple light LV, the blue limited light LBs, the green light LG, and the red light LR is controlled to a predetermined specific light amount, and is almost white.

  Further, in order to maintain the color rendering properties with a white light source such as a xenon lamp, discrete wavelengths are added to the spectral spectra of the violet light LV, the blue limited light LBs, the green light LG, and the red light LR irradiated to the observation target 24. Preferably there is no bandwidth. For this reason, the attenuation characteristic of the attenuation filter 21 has a characteristic of reducing light in a wavelength band of 460 nm or more to such an extent that the color rendering property with a xenon lamp or the like can be maintained.

  On the other hand, the light emitting element control unit 22 performs control to switch between the first light emitting mode and the second light emitting mode in the high image quality mode.

  In the first light emission mode, the blue light LB and the red light LR are simultaneously emitted by turning on the B-LED 20b and the R-LED 20d and turning off the V-LED 20a and the G-LED 20c. The blue light LB is converted into blue limited light LBs by the attenuation filter 21. Accordingly, in the first light emission mode, as shown in FIG. 7, the blue limited light LBs and the red light LR are combined by the optical path combining unit 23 and are irradiated on the observation target 24.

  In the second light emission mode, the purple light LV and the green light LG are emitted simultaneously by turning on the V-LED 20a and the G-LED 20c and turning off the B-LED 20b and the R-LED 20d. Accordingly, in the second light emission mode, as illustrated in FIG. 8, the violet light LV and the green light LG are combined by the optical path combining unit 23 and are irradiated onto the observation target 24.

  As described above, each color light emitted from each of the LEDs 20 a to 20 d is incident on the light guide 29 inserted into the insertion portion 12 a through the optical path coupling portion 23. The light guide 29 is built in the endoscope 12 and the universal cord (the cord connecting the endoscope 12, the light source device 14, and the processor device 16), and each color light from the optical path coupling unit 23 is received by the endoscope. By supplying to 12, each color light is propagated to the tip 12d. As the light guide 29, a multimode fiber can be used. As an example, a thin fiber cable having a core diameter of 105 μm, a cladding diameter of 125 μm, and a diameter including a protective layer serving as an outer shell of φ0.3 mm to 0.5 mm can be used.

  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 32. Light from the light guide 29 is applied to the observation object 24 via the illumination lens 32. The imaging optical system 30 b includes an objective lens 34 and an imaging element 36. The return light from the observation object 24 enters the objective lens 34 and is imaged on the imaging surface 36 a of the imaging device 36 by the objective lens 34.

  The image sensor 36 is a color image sensor such as a single-plate color CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and images the return light from the observation object 24 to obtain an image signal. Output. A plurality of pixels that generate pixel signals by photoelectric conversion are formed on the imaging surface 36 a of the imaging element 36.

  As shown in FIG. 9, a color filter array 38 is provided on the imaging surface 36a. The color filter array 38 includes a blue (B) filter 38a, a green (G) filter 38b, and a red (R) filter 38c. Each color filter 38a, 38b, 38c is arranged on the light incident side (that is, the objective lens 34 side) corresponding to one pixel. The color array of the color filter array 38 is called a Bayer array. Further, microlenses (not shown) are provided on the color filter array 38 corresponding to the respective pixels.

  As shown in FIG. 10, the B filter 38a has a spectral transmittance of 380 nm to 560 nm, the G filter 38b has a spectral transmittance of 450 nm to 630 nm, and the R filter 38c has a spectral transmittance of 580 nm to 760 nm. It has transmittance. A pixel provided with the B filter 38a (hereinafter referred to as a blue pixel) is sensitive to the blue light LB (and the blue limited light LBs) and the purple light LV, and has the blue light LB (and the blue limited light LBs) and the purple light. Each LV return light is received and a blue image signal is output. A pixel provided with the G filter 38b (hereinafter referred to as a green pixel) is sensitive to the green light LG, receives the return light of the green light LG, and outputs a green image signal. A pixel provided with the R filter 38c (hereinafter referred to as a red pixel) is sensitive to the red light LR, receives the return light of the red light LR, and outputs a red image signal. However, the above-described spectral transmittance is an example, and there is an image sensor that has some sensitivity to the blue light LB even if it is a red pixel, and an image sensor that has some sensitivity to the red light LR even if it is a blue pixel.

  The green pixel not only has sensitivity to the green light LG, but also has sensitivity to at least one of the blue light LB and the red light LR having a wavelength band adjacent to the wavelength band of the green light LG. For this reason, when the blue light LB and the red light LR are irradiated simultaneously with the green light LG, the green pixel receives not only the return light of the green light LG but also each return light of the blue light LB and the red light LR. Color mixing occurs.

  The image signal output from the image sensor 36 is transmitted to a CDS (Correlated Double Sampling) / AGC (Automatic Gain Control) circuit 40. The CDS / AGC circuit 40 performs correlated double sampling (CDS) and automatic gain control (AGC) on an image signal that is an analog signal. The image signal that has passed through the CDS / AGC circuit 40 is converted into a digital image signal by an A (Analog) / D (Digital) converter 42. The digital image signal from the A / D converter 42 is input to the processor device 16.

  The processor device 16 includes an imaging control unit 44, a receiving unit 46, a DSP (Digital Signal Processor) 48, a noise removing unit 50, an image processing switching unit 52, a normal image generating unit 54, and a high quality image generating unit. 56 (an image processing unit) and a video signal generation unit 58.

  The imaging control unit 44 receives the synchronization signal from the light emitting element control unit 22 (or by inputting the synchronization signal to the light emitting element control unit 22), and the light emission timing of the light emitting element control unit 22 and the imaging frame of the imaging element 36 are Synchronization and control of image signal output from the image sensor 36 are performed.

  As shown in Table 1, in the normal mode, since the observation object 24 is irradiated with normal light, the imaging device 36 is configured to transmit the purple light LV and the blue limited light LBs out of the normal light for each frame. Each return light is received by a blue pixel and a blue image signal is output. A return light of green light LG is received by a green pixel and a green image signal is output. A return light of red light LR is received by a red pixel. A red image signal is output. This imaging control is repeatedly performed while the normal mode is set.

  On the other hand, in the high image quality mode, as shown in Table 2, since the blue limited light LBs and the red light LR are irradiated to the observation target 24 in the first light emission mode, the image sensor 36 is in the first frame. Of the blue limited light LBs and the red light LR, the blue pixel receives the return light of the blue limited light LBs and outputs the first blue image signal, and the red pixel receives the return light of the red light LR and receives the first red light. Output image signal. Note that the first green image signal is output from the green pixel also in the first light emission mode.

  As shown in Table 3, since the observation object 24 is irradiated with the violet light LV and the green light LG in the second light emission mode, the imaging device 36 is the second frame and includes the violet light LV and the green light LG. The return light of the purple light LV is received by the blue pixel and the second blue image signal is output, and the return light of the green light LG is received by the green pixel and the second green image signal is output. Note that the second red image signal is output from the red pixel also in the second light emission mode.

  The blue limited light LBs and red light LR irradiated in the first light emission mode are separated from each other in wavelength band (see FIG. 7). Thus, the blue pixel receives only the return light when the observation target 24 is illuminated with the blue limited light LBs and does not receive the return light when the observation target 24 is illuminated with the red light LR. No color mixing with the red light LR occurs. For this reason, the first blue image signal obtained by imaging the return light of the blue limited light LBs is output from the blue pixel. Thus, the first blue image signal is not affected by the color mixture of the blue limited light LBs and the red light LR.

  The red pixel receives only the return light when the observation object 24 is illuminated with the red light LR and does not receive the return light when the observation object 24 is illuminated with the blue restriction light LBs. No color mixing with the light LR occurs. For this reason, a first red image signal obtained by imaging the return light of the red light LR is output from the red pixel. Thus, the first red image signal is not affected by the color mixture of the blue limited light LBs and the red light LR.

  On the other hand, the violet light LV and the green light LG in the second light emission mode are separated from each other in wavelength band (see FIG. 8). Accordingly, the blue pixel receives only the return light when the observation object 24 is illuminated with the purple light LV, and does not receive the return light when the observation object 24 is illuminated with the green light LG. Therefore, the purple light LV and the green light are received. Color mixing with LG does not occur. For this reason, a second blue image signal obtained by imaging the return light of the purple light LV is output from the blue pixel. Thus, the second blue image signal is not affected by the color mixture of the purple light LV and the green light LG.

  Further, since the green pixel receives only the return light when the observation object 24 is illuminated with the green light LG and does not receive the return light when the observation object 24 is illuminated with the purple light LV, the purple light LV and the green light LG are received. No color mixing occurs. For this reason, a second green image signal obtained by imaging the return light of the green light LG is output from the green pixel. Thus, the second green image signal is not affected by the color mixture of the purple light LV and the green light LG.

  As described above, the imaging control for two frames of the first frame and the second frame is repeatedly performed while the high image quality mode is set. In the high image quality mode, the first blue image signal and the first red image signal output in the first frame, and the second blue image signal and the second green image signal output in the second frame are used. Thus, a high-quality image is generated. As described above, since the first blue image signal, the first red image signal, the second blue image signal, and the second green image signal are not affected by the color mixture, the color reproducibility is good in the high image quality mode. A high quality image is generated.

  Further, since the information on the surface blood vessels is included in the return light when the observation target 24 is illuminated with the blue limited light LBs, the first blue image signal output in the first frame has the information on the surface blood vessels. . On the other hand, since the return light when the observation object 24 is illuminated with the purple light LV includes information on the polar surface blood vessels, the second blue image signal output in the second frame is Have information.

  The receiving unit 46 receives a digital image signal from the endoscope 12. The DSP 48 performs signal processing such as pixel interpolation processing, gamma correction, and color correction processing on the received image signal. The noise removing unit 50 removes noise from the image signal by performing noise removal processing (for example, a moving average method, a median filter method, etc.) on the image signal that has been subjected to various signal processing by the DSP 48. The image signal from which the noise has been removed is transmitted to the image processing switching unit 52.

  The image processing switching unit 52 transmits each color image signal obtained in the normal mode to the normal image generating unit 54 when the normal mode is set by the mode switching SW 13. When the high image quality mode is set by the mode switching SW 13, each color image signal obtained in the high image quality mode is transmitted to the high image quality image generation unit 56.

  The normal image generation unit 54 operates when the normal mode is set, and performs color conversion processing, color enhancement processing, and structure enhancement processing on the blue image signal, the green image signal, and the red image signal. Generate an image. In the color conversion processing, color conversion processing is performed on each color image signal 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 each color image signal that has been subjected to the color conversion process. The structure enhancement process is performed on each color image signal that has been subjected to the color enhancement process. For example, the structure of the observation target 24 such as a blood vessel or a pit pattern near the surface layer is enhanced. Then, a normal image is generated using the blue image signal, the green image signal, and the red image signal that have undergone the structure enhancement process. The generated normal images are sequentially transmitted to the video signal generator 58.

  The high-quality image generation unit 56 operates when the high-quality mode is set, and the first blue image signal, the first red image signal, the second blue image signal, and the second green image among the color image signals. A high-quality image is generated using the signal. The high-quality image generation unit 56 includes a signal addition unit 60 and an image generation unit 62. Note that the high-quality image generation unit 56 may perform color conversion processing, color enhancement processing, and structure enhancement processing in the same manner as the normal image generation unit 54.

  The signal adding unit 60 adds the first blue image signal and the second blue image signal among the first blue image signal, the first red image signal, the second blue image signal, and the second green image signal for each pixel. Then, an added blue image signal is obtained.

  As illustrated in FIG. 11, when generating the added blue image signal, the signal adding unit 60 adds the weights set in advance to the first blue image signal and the second blue image signal. For example, when the weight of the first blue image signal is “a” and the weight of the second blue image signal is “b”, the relationship “a <b” is satisfied (that is, the second blue image signal is satisfied). Is made larger than the weight of the first blue image signal). Specifically, the first blue image signal and the second blue image signal are weighted at a ratio of “1: 2” and added. Thus, the added blue image signal includes more information on the superficial blood vessels than on the superficial blood vessels. Such addition is performed for all pixels.

  The image generation unit 62 generates a high quality image from the added blue image signal, the first red image signal, and the second green image signal. Since the added blue image signal contains a lot of information on the superficial blood vessels, the high-quality image emphasizes the running pattern and pit pattern of the superficial blood vessels while maintaining the same color and brightness as the normal image. . The high-quality images generated by the image generation unit 62 are sequentially transmitted to the video signal generation unit 58.

  The video signal generation unit 58 converts the normal image received from the normal image generation unit 54 or the high quality image received from the high quality image generation unit 56 into a video signal for display as an image that can be displayed on the monitor 18. And sequentially output to the monitor 18. Thus, the normal image is displayed on the monitor 18 when a normal image is input, and the high-quality image is displayed when a high-quality image is input.

  Next, the effect | action of this invention is demonstrated along the flowchart shown in FIG. First, screening is performed in the normal mode (S10). At the time of this screening, when a site having a potential lesion (hereinafter referred to as a possible site of lesion) such as a brownish area or redness is detected (S11), the mode switching SW13 is operated to change the observation mode to the high image quality mode. Switch (S12).

  When the observation mode is switched to the high image quality mode, the light emitting element control unit 22 controls the light source unit 20 in the first light emission mode to irradiate the observation target 24 with the blue limited light LBs and the red light LR (S13). The imaging device 36 images each return light from the observation target 24 of the blue limited light LBs and the red light LR in the first frame, and outputs the first blue image signal, the first green image signal, and the first red image signal. Output (S14).

  Thereafter, the light emitting element control unit 22 automatically switches the light emission mode, controls the light source unit 20 in the second light emission mode, and irradiates the observation target 24 with the purple light LV and the green light LG (S15). The imaging device 36 images each return light from the observation target 24 of the purple light LV and the green light LG in the second frame, and outputs a second blue image signal, a second green image signal, and a second red image signal. (S16).

  In the high-quality image generating unit 56, the signal adding unit 60 calculates the added blue image signal by weighting and adding the first blue image signal and the second blue image signal (S17). Then, the image generation unit 62 generates a high-quality image from the added blue image signal, the first red image signal, and the second green image signal (S18). The high-quality image generated as described above is converted into a video signal by the video signal generator 58 and displayed on the monitor 18 (S19). The high image quality mode is repeated until the normal mode is switched (S20) or until the diagnosis is completed (S21).

  As described above, according to the present invention, in the high image quality mode, the first emission mode that emits the blue limited light LBs and the red light LR whose wavelength bands are separated from each other, and the purple light LV and the green light LG whose wavelength bands are separated from each other. By alternately switching to the second light emission mode for emitting light, each color pixel receives only the return light of the color corresponding to each color pixel, thereby preventing color mixing.

  In addition, when the high-quality image is generated, the extreme surface blood vessel is emphasized more than the surface blood vessel by using the added blue image signal in which the weight of the second blue image signal is larger than the weight of the first blue image signal. A high-quality image can be obtained.

[Second Embodiment]
In the first embodiment, light of two colors, blue limited light LBs and red light LR, is emitted during the first light emission mode, and light of two colors, purple light LV and green light LG, is emitted during the second light emission mode. However, in the second embodiment, three colors of light of violet light LV, blue limited light LBs, and red light LR are emitted during the first light emission mode, and only green light LG is emitted during the second light emission mode. Since the normal mode is the same as that of the first embodiment, the description thereof will be omitted, and the case of the high image quality mode will be described below.

  Both the violet light LV and the blue limited light LBs are narrowband light. It is preferable that brighter illumination light is used for distant view observation such as screening. Therefore, the violet light LV and the blue limited light LBs are simultaneously irradiated to obtain brighter illumination light so that the information of the blue image signal can be reliably obtained.

  In the first light emission mode, the light emitting element controller 22 turns on the V-LED 20a, the B-LED 20b, and the R-LED 20d and turns off the G-LED 20c, thereby turning the purple light LV, the blue limited light LBs, and the red light. The light LR is emitted simultaneously. Thereby, in the first light emission mode, as shown in FIG. 13, the violet light LV, the blue limited light LBs, and the red light LR are combined by the optical path coupling unit 23 and irradiated onto the observation target 24.

  As shown in Table 4, the imaging device 36 is the first frame when the observation target 24 is illuminated with the purple light LV and the blue limited light LBs among the purple light LV, the blue limited light LBs, and the red light LR. Each return light is received by the blue pixel and a first blue image signal is output, and the return light when the observation object 24 is illuminated by the red light LR is received by the red pixel and the first red image signal is output. Note that the first green image signal is output from the green pixel also in the first frame.

  On the other hand, in the second light emission mode, only the green light LG is emitted by turning on only the G-LED 20c and turning off the V-LED 20a, the B-LED 20b, and the R-LED 20d. Thereby, in the second light emission mode, as shown in FIG. 14, only the green light LG is irradiated to the observation object 24 via the optical path coupling unit 23.

  As shown in Table 5, the imaging device 36 receives the return light when the observation object 24 is illuminated with the green light LG in the second frame, and outputs a second green image signal. In the second frame, the second blue image signal is output from the blue pixel, and the second red image signal is output from the red pixel.

  Of the light emitted in the first emission mode, the wavelength band of the violet light LV and the blue limited light LBs and the wavelength band of the red light LR are separated from each other. Thereby, the blue pixel receives each return light when the observation target 24 is illuminated with the purple light LV and the blue limited light LBs, and does not receive the return light when the observation target 24 is illuminated with the red light LR. No color mixing occurs between the purple light LV and the blue limited light LBs and the red light LR. For this reason, the blue pixel outputs a first blue image signal obtained by imaging each return light of the purple light LV and the blue limited light LBs. Thus, the first blue image signal is not affected by the color mixture of the purple light LV, the blue limited light LBs, and the red light LR.

  The red pixel receives only the return light when the observation object 24 is illuminated with the red light LR, and does not receive each return light when the observation object 24 is illuminated with the purple light LV and the blue limited light LBs. No color mixing occurs between the light LR and the purple light LV and the blue limited light LBs. For this reason, a first red image signal obtained by imaging the return light of the red light LR is output from the red pixel. Thus, the first red image signal is not affected by the color mixture of the red light LR, the purple light LV, and the blue limited light LBs.

  On the other hand, only the green light LG is irradiated in the second light emission mode. Thereby, since the green pixel receives only the return light when the observation object 24 is illuminated with the green light LG, color mixing does not occur. For this reason, a second green image signal obtained by imaging the return light of the green light LG is output from the green pixel. Thus, the second green image signal is not affected by the color mixture.

  In the second embodiment, when the high-quality image is generated, the first blue image signal and the second blue image signal are not added. For this reason, the high-quality image generation unit 56 is not provided with the signal addition unit 60. Then, the image generation unit 62 generates a high-quality image with good color reproducibility from the first blue image signal, the first red image signal, and the second green image signal.

  As described above, in the second embodiment, in the high image quality mode, the first light emission mode that emits the purple light LV, the blue limited light LBs, and the red light LR, and the second light emission mode that emits only the green light LG. By alternately switching, it is possible to prevent color mixing between the purple light LV and the blue limited light LBs, the red light LR, and the green light LG. In addition, since the first blue image signal includes information on both the polar superficial blood vessel and the superficial blood vessel, both the polar superficial blood vessel and the superficial blood vessel are emphasized in the high-quality image.

[Third Embodiment]
In the first and second embodiments, some LEDs are turned on and the other LEDs are turned off in the high image quality mode. However, in the third embodiment, all the LEDs are turned on and the first light emitting mode is turned on. And the second light emission mode, the amount of light emitted from each LED is varied.

  The light emitting element control unit 22 lights all of the V-LED 20a, the B-LED 20b, the G-LED 20c, and the R-LED 20d in the first and second light emission modes, so that the purple light LV, the blue limited light LBs, and the green light are emitted. Light of four colors of light LG and red light LR is emitted.

  When the light emitting element control unit 22 is switched to the first light emission mode, as shown in FIG. 15, the light amount of the purple light LV is set to the light amount PV1, and the light amount of the blue limited light LBs is set to the light amount PBs1. The light quantity of the green light LG is set to the light quantity PG1, and the light quantity of the red light LR is set to the light quantity PR1. The light amount PBs1 of the blue limited light LBs is set by controlling the light amount of the blue light LB to the light amount PB1.

  On the other hand, when switched to the second light emission mode, as shown in FIG. 16, the light quantity of the purple light LV is set to the light quantity PV2, the light quantity of the blue limited light LBs is set to the light quantity PBs2, and the light quantity of the green light LG is set. The amount of light PG2 is set, and the amount of red light LR is set to the amount of light PR2. The light quantity PBs2 of the blue limited light LBs is set by controlling the light quantity of the blue light LB to the light quantity PB2.

  The light emitting element control unit 22 changes each light quantity of the purple light LV, the blue limited light LBs, the green light LG, and the red light LR between the first light emission mode and the second light emission mode. 20d is controlled.

  Specifically, regarding the light quantity of the purple light LV, the V-LED 20a is controlled in the first light emission mode and the second light emission mode so that the light quantity PV1 and the light quantity PV2 satisfy the relationship of PV1 <PV2. For example, the light quantity PV1 is 1/10 of the light quantity PV2.

  Regarding the light quantity of the blue limited light LBs, the B-LED 20b is controlled in the first light emission mode and the second light emission mode so that the light quantity PBs1 and the light quantity PBs2 satisfy the relationship of PBs1> PBs2. For example, the light quantity PBs2 is 1/10 of the light quantity PBs1.

  Regarding the light amount of the green light LG, the G-LED 20c is controlled in the first light emission mode and the second light emission mode so that the light amount PG1 and the light amount PG2 satisfy the relationship of PG1 <PG2. For example, the light quantity PG1 is 1/10 of the light quantity PG2.

  Regarding the light quantity of the red light LR, the R-LED 20d is controlled in the first light emission mode and the second light emission mode so that the light quantity PR1 and the light quantity PR2 satisfy the relationship of PR1> PR2. For example, the light quantity PR2 is 1/10 of the light quantity PR1.

  Thus, in the first light emission mode, the purple light LV, the blue limited light LBs, the green light LG, and the red light LR are emitted simultaneously, but the light amount PBs1 of the blue limited light LBs and the light amount PR1 of the red light LR are The spectral spectra are made larger than the light quantity PBs2 of the blue limited light LBs and the light quantity PR2 of the red light LR in the two light emission mode. On the other hand, the light amount PV1 of the purple light LV and the light amount PG1 of the green light LG are spectral spectra that are respectively smaller than the light amount PV2 of the purple light LV and the light amount PG2 of the green light LG in the second light emission mode. .

  On the other hand, in the second light emission mode, the violet light LV, the blue limited light LBs, the green light LG, and the red light LR are emitted simultaneously, but the light emission PV2 of the purple light LV and the light quantity PG2 of the green light LG are the first light emission. The spectral spectrum is set to be larger than the light amount PV1 of the purple light LV and the light amount PG1 of the green light LG in the mode. On the other hand, for the light quantity PBs2 of the blue limited light LBs and the light quantity PR2 of the red light LR, the spectral spectrum made smaller than the light quantity PBs1 of the blue limited light LBs and the light quantity PR1 of the red light LR in the first light emission mode, respectively. It becomes.

  As shown in Table 6, in the first light emission mode, the imaging device 36 uses the purple light LV and the blue limited light among the purple light LV, the blue limited light LBs, the green light LG, and the red light LR in the first frame. Each LBs return light is received by a blue pixel to output a first blue image signal, a green light LG return light is received by a green pixel and a first green image signal is output, and the red light LR return light is output. Light is received by the red pixel and a first red image signal is output.

  As shown in Table 7, in the second light emission mode, the image sensor 36 uses the purple light LV and the blue limited light among the purple light LV, the blue limited light LBs, the green light LG, and the red light LR in the second frame. Each LBs return light is received by a blue pixel and a second blue image signal is output. The green light LG return light is received by a green pixel and a second green image signal is output. The return light of the red light LR is received. The red pixel receives light and outputs a second red image signal.

  Of the light emitted in the first emission mode, the wavelength band of the blue limited light LBs, the wavelength band of the purple light LV, and the wavelength band of the green light LG are adjacent to each other, but the light amount PV1 of the purple light LV and The light amount PG1 of the green light LG is set smaller than the light amount PBs1 of the blue limited light LBs. Accordingly, the blue pixel receives more return light of the blue limited light LBs than each of the return light of the purple light LV and the green light LG, and therefore, between the blue limited light LBs, the purple light LV, and the green light LG. Occurrence of color mixing is suppressed. Note that since the wavelength band of the blue limited light LBs and the red light LR are separated from each other, no color mixing occurs. For this reason, from the blue pixel, a first blue image signal obtained by imaging a large amount of return light of the blue limited light LBs is output. Thus, the first blue image signal is suppressed from being affected by the color mixture of the blue limited light LBs, the purple light LV, and the green light LG.

  Of the light emitted in the first light emission mode, the wavelength band of the red light LR and the wavelength band of the green light LG are adjacent to each other, but the light quantity PG1 of the green light LG is the light quantity of the red light LR. It is set smaller than PR1. Thereby, since the red pixel receives more return light of the red light LR than the return light of the green light LG, the occurrence of color mixing between the red light LR and the green light LG is suppressed. For this reason, from the red pixel, a first red image signal obtained by imaging a large amount of return light of the red light LR is output. Thus, the first red image signal is suppressed from the influence of the color mixture of the red light LR and the green light LG.

  On the other hand, although the wavelength band of the purple light LV and the wavelength band of the blue limited light LBs are adjacent to each other in the light emitted in the second light emission mode, the light quantity PBs2 of the blue limited light LBs is equal to that of the purple light LV. The amount of light is set smaller than PV2. As a result, the blue pixel receives more return light of the violet light LV than the return light of the blue limited light LBs, so that color mixing between the violet light LV and the blue limited light LBs is suppressed. The purple light LV is not mixed with the green light LG and the red light LR because the wavelength bands are separated from each other. For this reason, a second blue image signal obtained by imaging a large amount of the return light of the purple light LV is output from the blue pixel. Thus, the influence of the color mixture of the purple light LV and the blue limited light LBs is suppressed in the second blue image signal.

  Of the light emitted in the second emission mode, the wavelength band of the green light LG, the wavelength band of the blue limited light LBs, and the wavelength band of the red light LR are adjacent to each other, but the blue limited light LBs The light amount PBs2 and the light amount PR2 of the red light LR are set smaller than the light amount PG2 of the green light LG. As a result, the green pixel receives more return light of the green light LG than each return light of the blue limited light LBs and the red light LR, and thus between the green light LG and the blue limited light LBs and the red light LR. Occurrence of color mixing is suppressed. For this reason, a second green image signal obtained by imaging a large amount of the return light of the green light LG is output from the green pixel. As described above, the second green image signal is suppressed from the influence of the color mixture of the green light LG, the blue limited light LBs, and the red light LR.

  In the third embodiment, a high-quality image generation unit 70 is provided as shown in FIG. 17 instead of the high-quality image generation unit 56 of the first and second embodiments. The high-quality image generation unit 70 is provided with a misalignment correction unit 72. The misregistration correction unit 72 performs alignment between the two frames of the image signal output in the first frame and the image signal output in the second frame.

  As shown in FIG. 18, the misregistration correction unit 72 includes a misregistration amount calculation unit 74 and a positioning unit 76. The positional deviation amount calculation unit 74 captures the return light from the observation target 24 illuminated with the same color light among the color image signals output in the first frame and the second frame, and outputs the image signal. The amount of misalignment between them is calculated. For example, a comparison operation of the first and second green image signals is performed on all the pixels of the first and second green image signals output by imaging the return light from the observation target 24 illuminated with the green light LG. Thus, the positional deviation amount in the X direction and the positional deviation amount in the Y direction are obtained. The positional deviation amounts in the X direction and the Y direction correspond to the positional deviation amount between the first frame and the second frame.

  The reason why the first and second green image signals are used to calculate the amount of displacement is that the position is compared with the case where the first and second blue image signals or the first and second red image signals are used. This is because the amount of deviation can be obtained accurately. In order to accurately determine the amount of displacement, it is preferable that the same structure is reflected in the images obtained from the image signal output in the first frame and the image signal output in the second frame. Here, the violet light LV and the blue limited light LBs necessary for the generation of the first and second blue image signals are greatly different in spectral spectrum between the first frame and the second frame (FIGS. 15 and 16). The structure shown in the image obtained from each of the first and second blue image signals is different. Specifically, the image obtained from the first blue image signal has more surface blood vessel structures than the structure of the polar surface blood vessels, and the image obtained from the second blue image signal has more structure than the surface blood vessels. Many structures of the superficial blood vessels are shown. In addition, since most of the red light LR necessary for generating the first and second red image signals is reflected without being absorbed by the observation target, the first and second red image signals have structures such as blood vessels. It is hardly visible.

  On the other hand, the green light LG necessary for generating the first and second green image signals does not change so much in the spectrum between the first frame and the second frame (see FIGS. 15 and 16). The structures shown in the images obtained from the first and second green image signals are almost the same. Therefore, the amount of positional deviation can be accurately obtained from the first and second green image signals.

  The alignment unit 76 performs alignment between the image signal output in the first frame and the image signal output in the second frame, using the positional shift amount obtained by the positional shift amount calculation unit 74. . Specifically, alignment is performed between the first blue image signal and the first red image signal and the second blue image signal and the second green image signal that are used when generating a high-quality image. When performing alignment, the image signal output in the first frame is moved in a direction to cancel the positional deviation between frames by the amount of positional deviation. As a result, the position of the image signal output in the first frame is matched with the position of the image signal output in the second frame, and the positional deviation between these two frames is eliminated. On the contrary, the image signal output in the second frame may be moved to match the image signal output in the first frame. Further, not only the image signal used when generating a high-quality image, but also alignment between the entire image signal output in the first frame and the entire image signal output in the second frame may be performed. good.

  In the high-quality image generation unit 70, the first blue image signal, the first red image signal, the second blue image signal, and the second green image signal that have been aligned are similar to those in the first embodiment. After various processing such as calculation of the added blue image signal is performed, a high-quality image is generated.

  As described above, in the third embodiment, when generating a high-quality image in the high-quality mode, the first blue image signal, the first red image signal, the second blue image signal, in which the influence of color mixing is suppressed, and Since the second green image signal is used, a high-quality image with better color reproducibility than a normal image can be obtained. In addition, since the positional deviation is corrected using an image signal between two frames obtained from the same color light, a clearer high-quality image is obtained.

  Furthermore, since each LED 20a-20d is always lit, the amount of light of each color light is preliminarily compared with the case where each LED 20a-20d is repeatedly turned on / off each time the first light emission mode and the second light emission mode are switched. The time (so-called rise time) until the set specific light amount is reached is shortened. By shortening the rise time as described above, it is possible to obtain a longer time during which imaging is performed with a specific light amount set in advance, so that the brightness of the high-quality image can be improved.

[Fourth Embodiment]
In the fourth embodiment, as in the third embodiment, in the high image quality mode, all the LEDs are turned on, and the amount of light emitted from each LED is varied between the first light emission mode and the second light emission mode. However, the pattern of the amount of light emitted from each LED is different from that of the third embodiment.

  As shown in FIG. 19, in the first light emission mode, the light emitting element control unit 22 sets the light amount of the purple light LV to the light amount PV1, sets the light amount of the blue limited light LBs to the light amount PBs1, and sets the light amount of the green light LG. Is set to the light amount PG1, and the light amount of the red light LR is set to the light amount PR1.

  As shown in FIG. 20, in the second light emission mode, the light amount of the purple light LV is set to the light amount PV2, the light amount of the blue limiting light LBs is set to the light amount PBs2, the light amount of the green light LG is set to the light amount PG2, The light quantity of the red light LR is set to the light quantity PR2.

  As described above, in the high image quality mode, the purple light LV, the blue limited light LBs, the red light LR, and the green light LG are simultaneously emitted. In the first light emission mode, the light amount PV1 of the purple light LV, the blue limited light LBs. The light amount PBs1 and the light amount PR1 of the red light LR are spectral spectra that are larger than the light amount PV2 of the purple light LV, the light amount PBs2 of the blue limited light LBs, and the light amount PR2 of the red light LR in the second light emission mode. It becomes. On the other hand, the light amount PG1 of the green light LG is a spectral spectrum that is smaller than the light amount PG2 of the green light LG in the second light emission mode.

  On the other hand, in the second light emission mode, the light amount PG2 of the green light LG is a spectrum that is larger than the light amount PG1 of the green light LG in the first light emission mode. On the other hand, for the light amount PV2 of the purple light LV, the light amount PBs2 of the blue limited light LBs, and the light amount PR2 of the red light LR, the light amount PV1 of the purple light LV and the light amount PBs1 of the blue limited light LBs in the first light emission mode. , And the red light LR light quantity PR1 respectively.

  Of the light emitted in the first emission mode, the wavelength band of the purple light LV and the blue limited light LBs and the wavelength band of the green light LG are adjacent to each other, but the light quantity PG1 of the green light LG is purple light. The light quantity PV1 of LV and the light quantity PBs1 of the blue limited light LBs are set smaller. Accordingly, the blue pixel receives more return light of the violet light LV and the blue limited light LBs than the return light of the green light LG, and therefore, between the purple light LV and the blue limited light LBs and the green light LG. Occurrence of color mixing is suppressed. Note that the purple light LV, the blue limited light LBs, and the red light LR are separated from each other in wavelength band, and thus no color mixing occurs. For this reason, the blue pixel outputs a first blue image signal obtained by imaging a large amount of each return light of the purple light LV and the blue limited light LBs. Thus, the first blue image signal is suppressed from the influence of the color mixture of the purple light LV and the blue limited light LBs and the green light LG.

  Of the light emitted in the first light emission mode, the wavelength band of the red light LR and the wavelength band of the green light LG are adjacent to each other, but the light quantity PG1 of the green light LG is the light quantity of the red light LR. It is set smaller than PR1. Thereby, since the red pixel receives more return light of the red light LR than the return light of the green light LG, the occurrence of color mixing between the red light LR and the green light LG is suppressed. For this reason, from the red pixel, a first red image signal obtained by imaging a large amount of return light of the red light LR is output. Thus, the first red image signal is suppressed from the influence of the color mixture of the red light LR and the green light LG.

  On the other hand, the wavelength band of the green light LG, the wavelength band of the blue limited light LBs, and the wavelength band of the red light LR are adjacent to each other in the light emitted in the second light emission mode, but the blue limited light LBs The light amount PBs2 and the light amount PR2 of the red light LR are set smaller than the light amount PG2 of the green light LG. As a result, the green pixel receives more return light of the green light LG than each return light of the blue limited light LBs and the red light LR, and thus between the green light LG and the blue limited light LBs and the red light LR. Occurrence of color mixing is suppressed. Note that the green light LG and the violet light LV are separated from each other in wavelength band, and thus no color mixing occurs. For this reason, a second green image signal obtained by imaging a large amount of the return light of the green light LG is output from the green pixel. As described above, the second green image signal is suppressed from the influence of the color mixture of the green light LG, the blue limited light LBs, and the red light LR.

  As shown in FIG. 21, the alignment unit 76 of the fourth embodiment uses the amount of misalignment between frames obtained by the amount of misregistration calculation unit 74 to generate a first blue image used for generating a high-quality image. The registration between the signal and the first red image signal and the second green image signal is performed. The alignment between the two frames is the same as in the third embodiment.

  In the high-quality image generation unit 70, various image processes are performed on the first blue image signal, the first red image signal, and the second green image signal that have been aligned, as in the second embodiment. As a result, a high-quality image is generated.

  As described above, in the fourth embodiment, when a high-quality image is generated in the high-quality mode, the first blue image signal, the first red image signal, and the second green image signal in which the influence of color mixture is suppressed are generated. Therefore, a high-quality image with better color reproducibility than a normal image can be obtained. In addition, since the positional deviation is corrected using an image signal between two frames obtained from the same color light, a clearer high-quality image is obtained.

  Further, since the LEDs 20a to 20d are always lit, as in the third embodiment, by shortening the rise time of the LEDs 20a to 20d, it is possible to obtain a longer time during which imaging is performed with a predetermined light amount, and to obtain a high-quality image. Can improve the brightness.

  In addition, the light emitting element control part 22 can perform control which switches the 1st light emission mode of 2nd Embodiment, and the 2nd light emission mode of 1st Embodiment. That is, the light emitting element control unit 22 emits three colors of light of purple light LV, blue limited light LBs, and red light LR in the first light emission mode (see FIG. 13), and purple light LV in the second light emission mode. Irradiate light of two colors with green light LG (see FIG. 8).

  In this case, in the first light emission mode, the imaging device 36 receives each return light of the violet light LV and the blue limited light LBs by the blue pixel and outputs the first blue image signal in the first frame, and outputs the red light LR. Is received by the red pixel and a first red image signal is output. On the other hand, in the second light emission mode, in the second frame, the return light of the purple light LV is received by the blue pixel and the second blue image signal is output, and the return light of the green light LG is received by the green pixel and the second frame is received. A green image signal is output.

  In addition, since the purple light LV is emitted in both the first light emission mode and the second light emission mode, the positional deviation correction unit 72 performs alignment using the first blue image signal and the second blue image signal. May be. Further, the signal adding unit 60 may add the first blue image signal and the second blue image signal to calculate the added blue image signal.

  In the first to fourth embodiments, light of a plurality of colors to be emitted in the first light emission mode is simultaneously emitted within the period of the first frame. However, the light of the plurality of colors is emitted within the period of the first frame. You may make it light-emit sequentially. Similarly, a plurality of colors of light emitted in the second light emission mode may be sequentially emitted within the period of the second frame. As described above, even when light of a plurality of colors is sequentially emitted in the first light emission mode and the second light emission mode, the same effect as in the first to fourth embodiments can be obtained.

  In the first to fourth embodiments, in the normal mode, by turning on the V-LED 20a, four colors of light of purple light LV, blue limited light LBs, green light LG, and red light LR are given to the observation object 24. Although the irradiation is performed, the V-LED 20a may be turned off, and the observation target 24 may be irradiated with light of three colors, the blue limited light LBs, the green light LG, and the red light LR.

  Further, when the added blue image signal is generated by the signal adding unit 60, the weight of the second blue image signal is set larger than the weight of the first blue image signal. It may be larger than the weighting of the two blue image signals. In this case, the added blue image signal includes more information on the superficial blood vessels than on the information on the superficial blood vessels. Thus, the weighting of the first blue image signal and the second blue image signal can be set as appropriate.

  In the present invention, the observation target 24 being illuminated is imaged and output in the first light emission mode, and an image signal is output, and the observation target 24 being illuminated is imaged and output in the second light emission mode. Furthermore, as shown in FIG. 22, even if the observation target 24 under illumination is imaged in the first light emission mode and the observation target 24 under illumination is imaged in the second light emission mode, an image signal is output. Good. In that case, it is preferable that the image sensor 36 can control the accumulation time in units of pixels. The accumulation time is preferably synchronized with the light emission period of the light emitting element.

  As a specific example, a case where the blue light LBs and the red light LR are irradiated in the first light emission mode and the green light LG is irradiated in the second light emission mode will be described. The light emitting element control unit 22 controls the B-LED 20b, the G-LED 20c, and the R-LED 20d to increase the light amount PBs1 of the blue limited light LBs among the blue limited light LBs, the red light LR, and the green light LG. It is set (indicated as “light amount: large” in FIG. 22), and the light amount PR1 of the red light LR is set to be the smallest (indicated as “light amount: small” in FIG. 22). The light amount PG2 of the green light LG is set to be smaller than the light amount PBs1 and larger than the light amount PR1 (indicated as “light amount: medium” in FIG. 22).

  Moreover, the light emitting element control part 22 controls the light emission period which light-emits each color light. The emission period of the blue limited light LBs is from the time when the emission mode is switched to the first emission mode until the time T1 elapses, and the emission period of the red light LR is the time after the emission mode is changed to the first emission mode. It is assumed that T2 elapses and the light emission period of the green light LG is until time T3 elapses after the light emission mode is switched to the second light emission mode. These times T1, T2, and T3 satisfy the relationship of T3> T1, T2. For this reason, the light emission period of the red light LR is lengthened (indicated as “period: long” in FIG. 22), and the light emission period of the blue limited light LBs and the light emission period of the green light LG are longer than the light emission period of the red light LR. It is shortened (in FIG. 22, it is expressed as “period: short”). In this way, the brightness and color tone of a high-quality image are controlled by controlling the amount of light and the length of the light emission period. In particular, by setting the light amount and the light emission period as described above, the total light amount of each color light is kept constant, and the hue and brightness like white light are maintained.

  The imaging control unit 44 performs accumulation control for controlling the accumulation time of the image sensor 36 in synchronization with the light emission period of each color light. The accumulation time is a time for converting the return light received by the pixel into a signal charge corresponding to the amount of light and accumulating it. In the first light emission mode, the first accumulation control is performed, and in the second light emission mode, the second accumulation control is performed. In the first accumulation control, the blue pixel accumulates the return light of the blue restricted light LBs as a signal charge during the emission period of the blue restricted light LBs for the same time as the time T1 when the blue restricted light LBs emits. Further, the red pixel accumulates the return light of the red light LR as a signal charge during the emission period of the red light LR for the same time as the time T2 when the red light LR emits light. On the other hand, in the second accumulation control, the green pixel accumulates the return light of the green light LG as a signal charge for the same period as the time T3 during which the green light LG emits during the emission period of the green light LG.

  In addition, when the first accumulation control and the second accumulation control are performed, the image sensor 36 reads signal charges from the respective color pixels, converts the signal charges into image signals, and outputs them. Specifically, the signal charge is read from the blue pixel, and the signal charge is converted into a first blue image signal and a second blue image signal and output. Similarly, the signal charge is read from the green pixel, and the signal charge is converted into a first green image signal and a second green image signal and output. The signal charge is read from the red pixel, and the signal charge is converted into a first red image signal and a second red image signal and output.

  Moreover, even when this invention is comprised as an endoscope system which has a component shown to the additional remarks mentioned later, the subject of this invention can be solved.

[Additional Item 1]
A blue light emitting element emitting blue light;
A red light emitting element emitting red light;
A green light emitting element emitting broadband green light;
A purple light emitting element that emits purple light;
A first light emitting mode in which the blue light, the red light, and the violet light are emitted, and the blue light amount and the violet light amount are set to a specific light amount ratio; and the green light is emitted. A light emitting element control unit that controls the blue light emitting element, the red light emitting element, the green light emitting element, and the violet light emitting element in two light emitting modes, and performs control to switch between the first light emitting mode and the second light emitting mode. When,
A blue pixel sensitive to the blue light and the violet light, a red pixel sensitive to the red light, a sensitivity to the green light, and among the blue light, the violet light and the red light. A color imaging device provided with a green pixel having sensitivity to at least one of the light;
An imaging control unit that captures an image of a subject under illumination in the first light emission mode and images an object under illumination in the second light emission mode and outputs an image signal;
An endoscope system comprising: an image processing unit that generates a specific image from the image signal.

[Additional Item 2]
The endoscope system according to claim 1, wherein the light emitting element control unit makes the light amount of the purple light larger than the light amount of the blue light.

  According to the endoscope system according to the supplementary item 2, the amount of violet light containing a lot of information on polar surface blood vessels is made larger than the amount of blue light containing a lot of information on surface blood vessels, so that A specific image in which the extreme surface blood vessels are emphasized rather than the blood vessels is generated.

[Additional Item 3]
The endoscope system according to claim 1, wherein the light emitting element control unit makes the light amount of the blue light larger than the light amount of the violet light.

  According to the endoscope system according to the supplementary item 3, the amount of blue light containing a large amount of surface blood vessel information is made larger than the amount of purple light containing a large amount of information on the superficial blood vessel, thereby increasing the polar light amount. A specific image in which the superficial blood vessels are emphasized rather than the superficial blood vessels is generated.

DESCRIPTION OF SYMBOLS 10 Endoscope system 12 Endoscope 14 Light source device 16 Processor apparatus 20 Light source part 20a V-LED
20b B-LED
20c G-LED
20d R-LED
DESCRIPTION OF SYMBOLS 21 Attenuation filter 22 Light emitting element control part 36 Image pick-up element 38 Color filter array 38a Blue (B) filter 38b Green (G) filter 38c Red (R) filter 44 Imaging control part 54 Normal image generation part 56,70 High quality image generation part Reference Signs List 60 signal adding unit 62 image generating unit 72 misregistration correction unit 74 misregistration amount calculation unit 76 registration unit

Claims (16)

A blue light emitting element emitting blue light;
A red light emitting element emitting red light;
A green light emitting element emitting broadband green light;
The blue light emitting element, the red light emitting element, and the green light emitting element are controlled by a first light emitting mode that emits the blue light and the red light and a second light emitting mode that emits the green light. A light emitting element control unit that performs control to switch between the light emitting mode and the second light emitting mode;
The blue pixel having sensitivity to the blue light, the red pixel having sensitivity to the red light, the sensitivity to the green light, and the sensitivity to at least one of the blue light and the red light. A color image sensor provided with a green pixel;
An imaging control unit that captures an image of a subject under illumination in the first light emission mode and images an object under illumination in the second light emission mode and outputs an image signal;
An endoscope system comprising: an image processing unit that generates a specific image from the image signal. It further has a purple light emitting element that emits purple light,
The endoscope system according to claim 1, wherein the blue pixel has sensitivity to the blue light and the violet light.   The said light emitting element control part controls the said purple light emitting element and the said green light emitting element so that the said purple light and the said green light may be light-emitted in the said 2nd light emission mode. Endoscope system. The imaging control unit outputs an image signal corresponding to each color pixel,
The image processing unit weights and adds the first blue image signal output from the blue pixel in the first light emission mode and the second blue image signal output from the blue pixel in the second light emission mode. A signal adding unit for obtaining the added blue image signal,
From the added blue image signal, the first red image signal output from the red pixel in the first light emission mode, and the second green image signal output from the green pixel in the second light emission mode, the specific image The endoscope system according to claim 3, further comprising: an image generation unit that generates   The endoscope system according to claim 4, wherein the signal adding unit makes the weighting of the second blue image signal larger than the weighting of the first blue image signal.   The light emitting element control unit controls the purple light emitting element, the blue light emitting element, and the red light emitting element to emit the purple light, the blue light, and the red light in the first light emission mode. The endoscope system according to claim 2. The imaging control unit outputs an image signal corresponding to each color pixel,
The image processing unit includes a first blue image signal output from the blue pixel in the first light emission mode, a first red image signal output from the red pixel in the first light emission mode, and the second light emission. The endoscope system according to claim 6, further comprising an image generation unit configured to generate the specific image from a second green image signal output from the green pixel in a mode. In the first light emission mode, the light emitting element controller emits the violet light with a light amount PV1, emits the blue light with a light amount PB1, emits the green light with a light amount PG1, and emits the red light with a light amount PR1. In the second light emission mode, the violet light is emitted with a light amount PV2, the blue light is emitted with a light amount PB2, the green light is emitted with a light amount PG2, and the red light is emitted with a light amount PR2. Let
In the first light emission mode, the light amount PB1 is made larger than the light amount PB2, the light amount PR1 is made larger than the light amount PR2, the light amount PV1 is made smaller than the light amount PV2, and the light amount PG1 is made the light amount. Smaller than PG2,
In the second light emission mode, the light amount PV2 is larger than the light amount PV1, the light amount PG2 is larger than the light amount PG1, the light amount PB2 is smaller than the light amount PB1, and the light amount PR2 is changed to the light amount PR2. The endoscope system according to claim 2, wherein the purple light emitting element, the blue light emitting element, the green light emitting element, and the red light emitting element are controlled so as to be smaller than PR1. In the first light emission mode, the light emitting element controller emits the violet light with a light amount PV1, emits the blue light with a light amount PB1, emits the green light with a light amount PG1, and emits the red light with a light amount PR1. In the second light emission mode, the violet light is emitted with a light amount PV2, the blue light is emitted with a light amount PB2, the green light is emitted with a light amount PG2, and the red light is emitted with a light amount PR2. Let
In the case of the first light emission mode, the light amount PV1 is made larger than the light amount PV2, the light amount PB1 is made larger than the light amount PB2, the light amount PR1 is made larger than the light amount PR2, and the light amount PG1 is made the light amount. Smaller than PG2,
In the second light emission mode, the light quantity PG2 is made larger than the light quantity PG1, the light quantity PV2 is made smaller than the light quantity PV1, the light quantity PB2 is made smaller than the light quantity PB1, and the light quantity PR2 is changed to the light quantity PR1. The endoscope system according to claim 2, wherein the purple light emitting element, the blue light emitting element, the green light emitting element, and the red light emitting element are controlled so as to be smaller. Misalignment between image signals output by imaging a subject illuminated with light of the same color among the image signals output in the first light emission mode and the image signals output in the second light emission mode A misregistration amount calculation unit for calculating the amount;
And an alignment unit configured to perform alignment between the image signal output in the first light emission mode and the image signal output in the second light emission mode based on the displacement amount. The endoscope system according to claim 8 or 9.   The endoscope system according to any one of claims 1 to 10, further comprising an attenuation filter that attenuates light having a specific wavelength within a range of 460 nm to 500 nm on an optical path of the blue light emitting element.   12. The internal view according to claim 1, wherein the light emitting element controller sequentially emits light from each color light emitting element in the first light emission mode and the second light emission mode. Mirror system.   The endoscope system according to claim 1, wherein the light emitting element control unit simultaneously emits light from the color light emitting elements. A blue light emitting element emitting blue light;
A red light emitting element emitting red light;
A green light emitting element emitting broadband green light;
The light emitting element control unit includes the blue light emitting element, the red light emitting element, and the green light emitting element in a first light emitting mode that emits the blue light and the red light and a second light emitting mode that emits the green light. Controlling and switching between the first light emission mode and the second light emission mode;
The imaging control unit has a blue pixel sensitive to the blue light, a red pixel sensitive to the red light, a sensitivity to the green light, and at least one of the blue light and the red light By controlling a color imaging device provided with a green pixel having sensitivity to light, the subject under illumination is imaged in the first light emission mode, and the subject under illumination is imaged in the second light emission mode. And outputting an image signal,
An operation method of the endoscope system, wherein the image processing unit includes a step of generating a specific image from the image signal. In an endoscope light source device that supplies light to an endoscope having a color image sensor provided with blue pixels, red pixels, and green pixels,
A blue light emitting element emitting blue light having sensitivity to the blue pixel;
A red light emitting element emitting red light having sensitivity to the red pixel;
A green light-emitting element that emits broadband green light having sensitivity to the green pixel and further having sensitivity to at least one of the blue pixel and the red pixel;
The blue light emitting element, the red light emitting element, and the green light emitting element are controlled by a first light emitting mode that emits the blue light and the red light and a second light emitting mode that emits the green light. A light source device comprising: a light emitting element control unit that performs control to switch between a light emission mode and the second light emission mode. In an operating method of an endoscope light source device for supplying light to an endoscope having a color imaging device provided with a blue pixel, a red pixel, and a green pixel,
A blue light emitting element emitting blue light having sensitivity to the blue pixel;
A red light emitting element emitting red light having sensitivity to the red pixel;
A green light emitting element emitting broadband green light having sensitivity to the green pixel and further having sensitivity to at least one of the blue pixel and the red pixel;
The light emitting element control unit includes the blue light emitting element, the red light emitting element, and the green light emitting element in a first light emitting mode that emits the blue light and the red light and a second light emitting mode that emits the green light. And a step of controlling and switching between the first light emission mode and the second light emission mode.