JP7159261B2 - endoscope system - Google Patents

Description

TECHNICAL FIELD The present invention relates to an endoscope system that acquires an endoscopic image of an observation target using a plurality of lights with different wavelengths, and in particular, even if the wavelength shift occurs in the light used for observation, the color tone of the endoscopic image can be obtained. It relates to an endoscopic system that maintains

2. Description of the Related Art In recent medical care, diagnosis using an endoscope system including a light source device for an endoscope, an electronic endoscope (endoscope), and a processor device is widely performed. An endoscope light source device generates illumination light and irradiates an observation target with the illumination light. An electronic endoscope uses an image sensor to capture an image of an observation target irradiated with illumination light to generate an image signal. The processor device processes the imaging signal generated by the electronic endoscope to generate an observation image to be displayed on the monitor.

Conventionally, light sources for endoscopes have used lamp light sources such as xenon lamps and halogen lamps that emit white light as illumination light. A semiconductor light source such as a laser diode (LD) or a light emitting diode (LED) is being used.

For example, Patent Literature 1 describes an endoscope system including a light source device that supplies illumination light to an endoscope. The light source device of Patent Document 1 includes a first semiconductor light source that is made of a semiconductor and emits first blue light, and a phosphor that is excited by the blue light and emits fluorescence containing a green component and a red component. a first light source section that emits white light in which the first blue light that has passed through and fluorescent light are mixed; and a blue light cut filter that is arranged on the optical path of the white light and cuts the first blue light that has passed through the phosphor. a second light source unit having a second semiconductor light source that emits a second blue light; a light mixing unit that mixes the second blue light and fluorescence to generate white light after the blue light cut filter; and a light source control section for controlling respective light amounts of the first and second light source sections.

JP 2014-161639 A

In Patent Document 1, when the color balance (light amount ratio) of fluorescence FL including G component (green component) and R component (red component) of white light and blue light B corresponding to B component (blue component) changes, , that the color of the observation site changes. On the other hand, Japanese Patent Laid-Open No. 2002-100000 discloses that the above-described configuration of the light source device performs light amount control to keep the light amount ratio between the fluorescence FL and the blue light B constant, so that it is possible to accurately correct the color balance. Have been described. As described above, in Patent Document 1, light amount control is performed to keep the light amount ratio constant, but in semiconductor light sources, wavelength shift may occur due to temperature drift due to emission intensity in addition to fluctuations in the light amount ratio. The wavelength shift may also change the color of the observation site, and in this case, it is necessary to make a correction in accordance with the wavelength shift, but the light amount control of Patent Document 1 cannot cope with this.

SUMMARY OF THE INVENTION An object of the present invention is to provide an endoscope system that solves the above-described problems based on the prior art and maintains the color tone of an endoscope image even when the wavelength of light for observation is shifted. .

In order to achieve the above object, the present invention provides a light source unit including at least one first light source that emits light containing two color components having different wavelengths, and two color components of the first light source. at least one of the image sensor having at least a first element unit having spectral sensitivity to the first color component and a second element unit having spectral sensitivity to the second color component, and at least one of the light source unit An image of an observation target is captured using light emitted from a light source, and a first signal value of a first color component obtained by a first element section of an image sensor and a second signal value obtained by a second element section are obtained. a processor for obtaining a second signal value of the color component, the processor determining a signal ratio between the first signal value and the second signal value to determine the ratio of the first signal value and the second signal value; , an endoscopic system that sets the signal ratio to a predetermined set value by varying at least one signal value.

The processor calculates a luminance value using at least one of the first signal value and the second signal value of the image sensor, identifies the amount of light of the first light source based on the luminance value, and determines the amount of light according to the amount of light. , the first signal value and the second signal value, the signal ratio is preferably set to a predetermined set value by varying at least one signal value.
The light source section has at least one second light source that emits light of a color other than the two color components, and the image sensor has a third element section having spectral sensitivity to light of a color other than the two color components. and the processor preferably obtains a third signal value for light of a color other than the two color components obtained at a third element portion of the image sensor.
The light source section has one first light source and one second light source, and the image sensor has a first element section, a second element section, and a third element section. , the processor converts the first signal value, the second signal value, and the third signal value obtained by the first element portion, the second element portion, and the third element portion, respectively, of the image sensor into It is preferable to obtain

The processor calculates a luminance value from at least one of a first signal value, a second signal value, and a third signal value of the image sensor, identifies the light quantity of the first light source based on the luminance value, and calculates the light quantity Preferably, the signal ratio is set to a predetermined set value by varying at least one signal value of the first signal value, the second signal value and the third signal value in response to .
The processor calculates a luminance value from at least one of a first signal value, a second signal value, and a third signal value of the image sensor, identifies the light quantity of the first light source based on the luminance value, and calculates the light quantity , one of the first signal value, the second signal value and the third signal value is used as a reference value to obtain the first signal value, the second signal value and the third signal value Preferably, the signal ratio is set to a predetermined set value by changing at least one signal value.

The light of colors other than the two color components is light showing blue, and it is preferable that the first color component of the two color components is green and the second color component is red.
Light of colors other than the two color components is light exhibiting red, and it is preferable that the first color component of the two color components is blue and the second color component is green.
The light source unit includes, as a first light source, a light source that emits light containing a first color component representing green and a second color component representing red, or a first color component representing blue and a second color component representing green. It is preferable to have a light source that emits light containing the component.
The light source unit includes, as a first light source, a light source that emits light including a first color component representing green and a second color component representing red, and a first color component representing blue and a second color component representing green. It is preferable to have a light source that emits light containing the component.

The first light source preferably has a light-emitting element that emits excitation light, and a phosphor that emits light containing the first color component and the second color component by the excitation light.
Preferably, the first light source comprises a light emitting diode with an emission spectrum comprising a first color component and a second color component.
The first light source preferably has a light-emitting diode having an emission peak between the spectral sensitivity peak wavelength of the first element portion and the spectral sensitivity peak wavelength of the second element portion.
In the image sensor, it is preferable that the spectral sensitivity of the first element portion and the spectral sensitivity of the second element portion overlap each other.

The present invention provides a light source unit that includes at least one first light source that emits light containing two color components having different wavelengths, and a spectrum for the first color component of the two color components of the first light source. using light emitted from an image sensor having at least a first element section having sensitivity and a second element section having spectral sensitivity to a second color component, and at least one first light source of the light source section An image of an observation target is captured, and a first signal value of the first color component obtained by the first element section of the image sensor and a second signal value of the second color component obtained by the second element section of the image sensor are obtained. and a processor for obtaining a signal ratio between the first signal value and the second signal value, wherein the first light source determines the ratio of the first color component and the second color component according to the amount of light emitted from the first light source. The light intensity ratio changes, the processor calculates a luminance value using at least one of the first signal value and the second signal value of the image sensor, and identifies the light intensity of the first light source based on the luminance value. and at least one of the first signal value and the second signal value is changed according to the amount of light so that the signal ratio becomes a predetermined set value. is.

According to the present invention, it is possible to maintain the color tone of an endoscopic image regardless of the amount of light.

1 is a perspective view conceptually showing an example of an endoscope system according to a first embodiment of the present invention; FIG. 1 is a block diagram conceptually showing an example of an endoscope system according to a first embodiment of the present invention; FIG. It is a schematic diagram showing an example of an image sensor of the endoscope system of the first embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of arrangement of color filters of the image sensor of the endoscope system according to the first embodiment of the present invention; It is a mimetic diagram showing an example of a light source part of an endoscope system of a 1st embodiment of the present invention. 4 is a graph showing an example of the emission spectrum of the light source section and the spectral sensitivity of the image sensor of the endoscope system according to the first embodiment of the present invention; 4 is a graph showing wavelength shift due to changes in the amount of light in the emission spectrum of the light source unit of the endoscope system according to the first embodiment of the present invention; 4 is a graph showing an example of variation in signal ratio in the image sensor of the endoscope system according to the first embodiment of the present invention; 4 is a graph showing an example of wavelength shift due to changes in the amount of light in the emission spectrum of the light source unit of the endoscope system of the first embodiment of the present invention and spectral sensitivity of the image sensor. It is a graph which shows an example of the signal correction coefficient of the endoscope system of the 1st Embodiment of this invention. It is a schematic diagram which shows the modification of an example of the light source part of the endoscope system of the 1st Embodiment of this invention. It is a schematic diagram which shows an example of the light source part of the endoscope system of the 2nd Embodiment of this invention. 9 is a graph showing an example of the emission spectrum of the light source section and the spectral sensitivity of the image sensor of the endoscope system according to the second embodiment of the present invention; FIG. 10 is a graph showing an example of variation in signal ratio in the image sensor of the endoscope system according to the second embodiment of the present invention; FIG.

The endoscope system of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings.
It should be noted that the drawings described below are examples for explaining the present invention, and the present invention is not limited to the drawings shown below.
In the following, "~" indicating a numerical range includes the numerical values described on both sides. For example, when ε is a numerical value α to a numerical value β, the range of ε is a range including the numerical values α and β, and represented by mathematical symbols α≦ε≦β.
Angles such as "parallel" include the error range generally accepted in the relevant technical field unless otherwise specified. "Identical" includes a margin of error generally accepted in the relevant technical field unless otherwise specified.

In general, the wavelength of blue is about 445 nm to about 485 nm. For example, a color intermediate between blue and green is sometimes called bluish green to distinguish it from blue. However, in the endoscope system 10, there is no need to excessively subdivide the types of colors (names of colors) of the light emitted by at least the light sources of the light source section. Therefore, the color of light having a wavelength of approximately 440 nm or more and less than approximately 490 nm is called blue. Also, the color of light having a wavelength of about 490 nm or more and less than about 600 nm is called green, and the color of light having a wavelength of about 600 nm or more and less than about 680 nm is called red. Then, visible light having a wavelength of less than "about 440 nm", which is the lower limit of the wavelength of blue described above, for example, the color of visible light of about 380 nm or more and less than about 440 nm is called violet. Ultraviolet is used to describe the color of light to which sensor 48 is sensitive. Further, the term "infrared" refers to the color of light having a wavelength of "approximately 680 nm" or more, which is the upper limit of the red wavelength, and to which the image sensor 48 is sensitive. Also, the term "broadband" means that the wavelength range extends to the wavelength ranges of a plurality of colors. White refers to the color of light including at least the light belonging to blue or violet, the light belonging to green, and the light belonging to red.

[First embodiment]
FIG. 1 is a perspective view conceptually showing an example of the endoscope system according to the first embodiment of the present invention, and FIG. 2 conceptually shows an example of the endoscope system according to the first embodiment of the present invention. It is a block diagram showing.
As shown in FIG. 1, an endoscope system 10 includes an endoscope (hereinafter simply referred to as an endoscope) 12 that captures an image of an observation target in vivo (inside a subject), and A processor device 16 for generating a display image of an observed region based on the obtained image signal, and an endoscope light source device (hereinafter simply referred to as a light source device) for supplying the endoscope 12 with illumination light for illuminating the observed region. 14 and a monitor 18 for displaying a display image. A console 19, which is an operation input unit such as a keyboard and a mouse, is connected to the processor unit 16. FIG.

The endoscope system 10 can perform a normal observation mode for observing an observation site and a blood vessel enhancement observation mode for emphasizing and observing blood vessels existing inside the mucous membrane of the observation site. The blood vessel enhancement observation mode is a mode for visualizing patterns of blood vessels as blood vessel information and diagnosing whether a tumor is good or bad. In this blood vessel enhancement observation mode, an observation region is irradiated with illumination light containing many light components in a specific wavelength band with high absorbance for blood hemoglobin.
In the normal observation mode, a normal observation image suitable for observing the entire observation site is generated as a display image. In the blood vessel-enhanced observation mode, a blood vessel-enhanced observation image suitable for observation of blood vessel patterns is generated as a display image.

The endoscope 12 includes an insertion section 12a to be inserted into the subject, an operation section 12b provided at the proximal end portion of the insertion section 12a, a bending section 12c provided at the distal end of the insertion section 12a, and a distal end section 12d. have The bending portion 12c is bent by operating the angle knob 12e of the operation portion 12b. As a result of bending the bending portion 12c, the tip portion 12d faces in a desired direction. The distal end portion 12d is provided with an injection port (not shown) for injecting air, water, or the like toward the observation target. In addition to the angle knob 12e, the operation unit 12b also includes a forceps port for inserting a treatment instrument, an air/water supply button operated when supplying air or water from the air/water supply nozzle, and a still image. A freeze button (not shown), a zoom operation section 13a, and a mode changeover switch 13b are provided for this purpose. The zoom operation unit 13a is used when enlarging or reducing the observation target. The mode changeover switch 13b is used for switching observation modes when the endoscope system 10 has a plurality of observation modes.

Endoscope 12 also includes a universal cord 17 for connecting endoscope 12 to processor unit 16 and light source unit 14 .
A communication cable or light guide 41 (see FIG. 2) extending from the insertion portion 12a is inserted through the universal cord 17, and a connector is attached to one end on the processor device 16 and light source device 14 side. . The connector is a composite type connector consisting of a communication connector and a light source connector. The communication connector and the light source connector are detachably connected to the processor device 16 and the light source device 14, respectively. One end of a communication cable is arranged in the communication connector. An incident end of a light guide 41 is arranged in the light source connector.

As shown in FIG. 2, the light source device 14 includes a light source unit 20 having two or more light sources having different dominant wavelengths, a light source control unit 22 for controlling light emission timing and light emission amount of the light source unit 20, and a light source control unit. and a light source driving unit 21 that generates a driving current according to the control signal of 22 and supplies the driving current (driving signal) to each light source to emit light.

In the light source device 14, the light source control unit 22 drives the light source so that the illumination light Ls (see FIG. 5) from the light source unit 20 is irradiated to the object Ob (see FIG. 5), which is the observation target, with a specific amount of light. It controls the unit 21 . For example, even if the distance Ld (see FIG. 5) between the distal end portion 12d (see FIG. 5) of the endoscope and the object Ob (see FIG. 5) changes, the brightness of the endoscopic image is kept constant. It controls the amount of illumination light Ls. In this case, for example, the brightness value obtained from the sensor signal of the image sensor 48 is used to control the light amount of the illumination light Ls so that the brightness value is constant.
In this case, the light source unit 20 is provided with photodetectors 91, 92, and 93 (see FIG. 5) as described later. is input to the light source control unit 22, and information on the light intensity of each light source is obtained. Based on the information on the light quantity of each light source and the luminance value of the image sensor 48, the light emission quantity of the light source of the light source unit 20 is automatically and accurately controlled.

Illumination light emitted from the light source unit 20 enters the light guide 41 . The light guide 41 is built in the endoscope 12 and the universal cord 17, and propagates the illumination light to the distal end portion 12d of the endoscope 12. As shown in FIG. The universal cord 17 is a cord that connects the endoscope 12 , the light source device 14 and the processor device 16 . A multimode fiber can be used as the light guide 41 . As an example, a thin fiber cable having a core diameter of 105 μm, a clad diameter of 125 μm, and a diameter including a protective layer serving as an outer sheath of 0.3 to 0.5 mm can be used.

A distal end portion 12d of the endoscope 12 is provided with an illumination optical system 30a and a photographing optical system 30b. The illumination optical system 30a has an illumination lens 45 through which illumination light is applied to an observation target. The imaging optical system 30 b has an objective lens 46 , a zoom lens 47 and an image sensor 48 . The image sensor 48 captures an image of the observation target using the reflected light of illumination light returning from the observation target via the objective lens 46 and the zoom lens 47 . The reflected light of the illumination light returning from the observation target includes scattered light, fluorescence emitted from the observation target, fluorescence caused by a drug administered to the observation target, and the like, in addition to the reflected light.
Note that the zoom lens 47 is moved by operating the zoom operation section 13a. As a result, the observation target photographed using the image sensor 48 is enlarged or reduced for observation.

The image sensor 48 uses, for example, a photoelectric conversion element such as a CCD (Charge Coupled Device) sensor and a CMOS (Complementary Metal Oxide Semiconductor) sensor. The image sensor 48 using a photoelectric conversion element photoelectrically converts received light and accumulates signal charges corresponding to the amount of light received for each pixel as a sensor signal. A signal charge for each pixel is converted into a voltage signal and read out from the image sensor 48 . A voltage signal for each pixel read from the image sensor 48 is input to a DSP (Digital Signal Processor) 56 as an image signal.
The image sensor 48 performs, for example, an accumulation operation of accumulating signal charges in pixels and a reading operation of reading out the accumulated signal charges within an acquisition period of one frame. The light source device 14 generates illumination light in accordance with the timing of the accumulation operation of the image sensor 48 and makes it enter the light guide 41 .

The image sensor 48 has, as shown in FIG. An element portion 48a, a second element portion 48b and a third element portion 48c are configured. Signal charges are accumulated as sensor signals in the pixel section 49 having a photoelectric conversion function as described above.
In the image sensor 48, the first element section 48a has a first pixel 49a having a photoelectric conversion function and a first filter 50a having spectral sensitivity to the first color component. A first signal value of the first color component is obtained in the first element portion 48 a according to the light incident on the image sensor 48 .
The second element section 48b has a second pixel 49b having a photoelectric conversion function and a second filter 50b having spectral sensitivity to the second color component. A second signal value of the second color component is obtained in the second element portion 48 b according to the light incident on the image sensor 48 .
The third element portion 48c has a third pixel 49c having a photoelectric conversion function and a third filter 50c having spectral sensitivity to the third color component. The third color component is a color other than the first color component and the second color component. A third signal value of the third color component is obtained in the third element portion 48c according to the light incident on the image sensor 48. FIG.

The image sensor 48 has, for example, a color filter for each pixel, and is a primary color sensor. The first filter 50a, the second filter 50b and the third filter 50c are composed of, for example, color filters. In this case, the first filter 50a, the second filter 50b, and the third filter 50c of the image sensor 48 are, for example, an R color filter (red color filter), a G color filter (green color filter), and a B color filter (blue color filter). filter). The first element portion 48a, the second element portion 48b, and the third element portion 48c are appropriately determined according to the above-described first color component, second color component, and third color component.
Among the pixels of the first pixel 49a, the second pixel 49b, and the third pixel 49c, the pixel having the R color filter is the R pixel, the pixel having the G color filter is the G pixel, and the pixel having the B color filter is The pixels that have are B pixels. As sensor signals of the image sensor 48, an R signal is obtained from the R pixel, a G signal is obtained from the G pixel, and a B signal is obtained from the B pixel. The R signal, G signal and B signal are input to the DSP 56 as image signals.
In this way, the image sensor 48 has pixels of three colors, for example, R pixels, G pixels, and B pixels. Therefore, when an object to be observed is photographed using white light as illumination light, the object to be observed is captured by the R pixels. An R image obtained by photographing, a G image obtained by photographing an observation object with G pixels, and a B image obtained by photographing an observation object with B pixels are simultaneously obtained.

Although the arrangement of the R color filter 50R (see FIG. 4), the G color filter 50G (see FIG. 4) and the B color filter 50B (see FIG. 4) is not particularly limited, for example, as shown in FIG. , are arranged at a ratio of R:G:B=1:2:1 in consideration of visibility.
For example, the signal value of the R signal corresponds to the second signal value, the signal value of the G signal corresponds to the first signal value, and the signal value of the B signal corresponds to the third signal value. .

Although the image sensor 48 is exemplified as a primary color sensor, the present invention is not limited to this, and a complementary color sensor can also be used. Complementary color sensors include, for example, cyan pixels provided with cyan color filters, magenta pixels provided with magenta color filters, yellow pixels provided with yellow color filters, and green pixels provided with green color filters. have When a complementary color system color sensor is used, the images obtained from the above pixels of each color can be converted into a B image, a G image, and an R image by performing complementary primary color conversion. Also, a monochrome sensor without a color filter can be used as the image sensor 48 instead of the color sensor. In this case, the image of each color can be obtained by sequentially photographing the object to be observed using illumination light of each color such as BGR.

In addition, the insertion portion 12a shown in FIG. 1 includes a communication cable for communicating a drive signal for driving the image sensor 48 and an image signal output by the image sensor 48, and guides the illumination light supplied from the light source device 14 to the illumination window. A light guide 41 is inserted.

As shown in FIG. 2 , the processor device 16 has an image acquisition section 54 , a correction amount calculation section 60 , an image processing section 61 , a display control section 66 and a control section 69 . The processor device 16 corresponds to the processor of the present invention.
The image acquisition unit 54 acquires an image signal from each pixel of the image sensor 48 and acquires a photographed image of multiple colors obtained by photographing an observation target using the image sensor 48 . Specifically, the image acquisition unit 54 acquires a set of B, G, and R images for each captured frame. The image acquisition unit 54 also has a DSP 56, a noise reduction unit 58, and a conversion unit 59, and uses these to perform various processing on the acquired captured image. For example, R signal, G signal, and B signal obtained as sensor signals from each pixel of the image sensor 48 are output to the correction amount calculator 60 and the controller 69 .

The DSP 56 performs various types of processing such as defect correction processing, offset processing, gain correction processing, linear matrix processing, gamma conversion processing, demosaicing processing, and YC conversion processing on the acquired photographed image as necessary. Further, the DSP 56 obtains a luminance value from the sensor signal of the image sensor 48 input as an image signal. Note that, for example, a G signal may be used as the luminance value.

The defect correction process is a process of correcting pixel values of pixels corresponding to defective pixels of the image sensor 48 .
Offset processing is processing for reducing dark current components from an image subjected to defect correction processing and setting an accurate zero level.
The gain correction process is a process of adjusting the signal level of each image by multiplying the offset-processed image by a gain.
Linear matrix processing is processing that enhances the color reproducibility of an image that has undergone offset processing, and gamma conversion processing is processing that adjusts the brightness or saturation of an image after linear matrix processing.
Demosaic processing (also referred to as isotropic processing or synchronization processing) is processing for interpolating pixel values of missing pixels, and is performed on an image after gamma conversion processing. A missing pixel is a pixel that has no pixel value due to the arrangement of the color filters and the placement of pixels of other colors in the image sensor 48 . For example, since a B image is an image obtained by photographing an observation target at B pixels, pixels at positions corresponding to G pixels and R pixels of the image sensor 48 have no pixel values. The demosaicing process interpolates the B image to generate pixel values for the pixels located at the G and R pixels of image sensor 48 .
YC conversion processing is processing for converting an image after demosaic processing into a luminance channel Y, a color difference channel Cb, and a color difference channel Cr.

The noise reduction unit 58 performs noise reduction processing on the luminance channel Y, the color difference channel Cb, and the color difference channel Cr using, for example, the moving average method or the median filter method.
The conversion unit 59 reconverts the luminance channel Y, the color difference channel Cb, and the color difference channel Cr after the noise reduction process into BGR color images.
The correction amount calculation unit 60 performs correction for maintaining the color tone of the endoscopic image, and calculates correction coefficients, which will be described later, and stores the correction coefficients.

The image processing unit 61 performs color conversion processing, color enhancement processing, and structure enhancement processing on the B image, G image, and R image of one captured frame that have undergone the various types of processing described above, and generates an observation image. do. In the color conversion processing, 3×3 matrix processing, gradation conversion processing, three-dimensional LUT (lookup table) processing, or the like is performed on each BGR color image. Color enhancement processing is processing that enhances the colors of an image, and structure enhancement processing is processing that enhances tissues or structures of observation targets such as blood vessels and pit patterns, for example.

The display control unit 66 sequentially acquires observation images from the image processing unit 61 , converts the acquired observation images into a format suitable for display, and sequentially outputs and displays them on the monitor 18 . Accordingly, a doctor or the like can observe an observation target using a still image or a moving image of an observation image.

The control unit 69 has, for example, a CPU (Central Processing Unit), and performs overall control of the endoscope system 10 such as synchronous control of emission timing of illumination light and imaging frames. Further, when the endoscope system 10 has a plurality of observation modes, the control section 69 switches illumination light via the light source control section 22 by receiving an operation input from the mode switching switch 13b. This switches the observation mode.

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

The configuration and action of the light source device 14 will be described in more detail below. FIG. 5 is a schematic diagram showing an example of the light source section of the endoscope system according to the first embodiment of the present invention.
As shown in FIG. 5 , the light source section 20 of the light source device 14 has a first light source 71 , a second light source 72 and an additional light source 74 . The first light source 71, the second light source 72, and the additional light source 74 are each independently controllable. The light source unit 20 also includes a cooling member such as a heat sink for cooling the light emitting elements of the first light source 71 , the second light source 72 , and the additional light source 74 .
In the light source device 14, the light emitted from the light source unit 20 passes through the light guide 41 and is irradiated onto the object Ob as illumination light Ls. The reflected light Lr of the illumination light Ls applied to the object Ob is incident on the image sensor 48 via the objective lens 46 .

The first light emitted by the first light source 71 is incident on the light guide 41 via a combining member 77 and a lens 78 through which the first light passes.
A beam splitter 94 is provided between the first light source 71 and the combining member 77 . A part of the first light emitted by the first light source 71 is reflected by the beam splitter 94 at a predetermined rate. Light reflected by the beam splitter 94 is received by the photodetector 91 . The light source control unit 22 automatically and accurately controls the emission amount of the first light from the first light source 71 using the light amount detected by the photodetector 91 .

The second light emitted by the second light source 72 enters the light guide 41 via the combining member 76 and the combining member 77 that transmit the second light, and the lens 78 .
A beam splitter 95 is provided between the second light source 72 and the combining member 76 . A part of the second light emitted by the second light source 72 is reflected by the beam splitter 95 at a predetermined rate. Light reflected by the beam splitter 95 is received by the photodetector 92 . The light source controller 22 automatically and accurately controls the amount of second light emitted from the second light source 72 using the amount of light detected by the photodetector 92 .

The light emitted by the additional light source 74 enters the light guide 41 via the combining member 76 and the combining member 77 that transmit the light emitted by the additional light source 74 and the lens 78 .
A beam splitter 96 is provided between the additional light source 74 and the combining member 76 . A part of the light emitted by the additional light source 74 is reflected by the beam splitter 96 at a predetermined rate. Light reflected by the beam splitter 96 is received by the photodetector 93 . The light source controller 22 automatically and accurately controls the amount of light emitted from the additional light source 74 using the amount of light detected by the photodetector 93 .

The wave combining member 76 and the wave combining member 77 are, for example, dichroic mirrors or dichroic prisms. The lens 78 is for narrowing down the light from the light source section 20 and making it enter the light guide 41 .
The photodetectors 91, 92, and 93 are, for example, photomultiplier tubes that utilize the photoelectric effect, photoconductive elements such as CdS and PbS that utilize electrical resistance changes due to light irradiation, or photovoltaic devices that utilize pn junctions of semiconductors. It is a power type photodiode or the like.

The first light source 71 includes a light emitting element 81 that emits light containing two color components with different wavelengths, and a lens that adjusts the first light emitted by the light emitting element 81 into parallel light or the like. 82. The light emitting element 81 is, for example, a semiconductor element such as an LED (light emitting diode) or an LD having an emission spectrum including a first color component and a second color component among two color components with different wavelengths.
The first light source 71 emits green light (hereinafter referred to as green light) including two color components having different wavelengths, for example, green as the first color component and red as the second color component. is. Light of one color is used as light of two colors. Green light is also called green light.

The second light source 72 includes a light emitting element 83 that emits second light as light of a color other than the two color components having different wavelengths, and converts the second light emitted from the light emitting element 83 into parallel light or the like. and a trimming lens 84 . The light emitting element 83 is, for example, a semiconductor element such as an LED or LD.
In the first light source 71, of the two color components with different wavelengths, for example, when the first color component is green and the second color component is red, the second light source 72 consists of a blue component. It emits light (hereinafter referred to as blue light). Blue light is also referred to as light exhibiting blue color.
The first light source 71 may be blue light with a first color component of blue and a second color component of green. In this case, the second light source 72 is one that emits light composed of a red component (hereinafter referred to as red light). Red light is also referred to as light exhibiting red color.

Two color components having different wavelengths means that there are two color components that can be separated. Here, as described above, blue light is light having a wavelength of approximately 440 nm or more and less than approximately 490 nm. Green light is light having a wavelength greater than or equal to about 490 nm and less than about 600 nm. Red light is light having a wavelength greater than or equal to about 600 nm and less than about 680 nm. For example, light with a wavelength range of 490 nm to 700 nm includes the green light and red light described above. Also, if the wavelength range is 440 nm to 600 nm, it includes the blue light and green light described above.
In addition, in two or more light sources having different dominant wavelengths, different dominant wavelengths means that the peak wavelengths of the light emitted from the respective light sources and, if there is no peak wavelength, the center wavelengths are not the same wavelength. The same range of peak wavelengths or central wavelengths is appropriately determined according to the specifications of the endoscope system 10 or the like.

The additional light source 74 emits, for example, light composed of violet components (hereinafter referred to as violet light). The additional light source 74 includes a light emitting element 86 and a lens 87 that arranges the purple light emitted by the light emitting element 86 into parallel light or the like. The light emitting element 86 is, for example, a semiconductor element such as an LED or LD. The violet light emitted by the additional light source 74 enters the light guide 41 via a combining member 76 that reflects the violet light and a combining member 77 that transmits the violet light. The violet component of the violet light is received by the B pixels in the image sensor 48 . Therefore, the reflected violet light contributes to the B image together with the reflected blue light and the like.

In the normal observation mode, the light source control section 22 turns on the first light source 71 and the second light source 72 and turns off the additional light source 74 . On the other hand, in the blood vessel enhanced observation mode, the light source control section 22 turns on all of the first light source 71, the second light source 72, and the additional light source 74. FIG.
When the first light source 71 emits green light in which the first color component is green and the second color component is red, and the second light source 72 emits blue light, in the normal observation mode, the first light source 71 The emitted light including green light and red light is combined with the blue light emitted by the second light source 72 to generate broadband white light. On the other hand, in the blood vessel enhancement observation mode, mixed light is generated by mixing white light with violet light, which has high absorbance for blood hemoglobin. Note that the light source control unit 22 reduces the ratio of the amount of blue light so that the violet light is dominant over the blue light in the blood vessel enhancement observation mode.

The light source device 14 having the configuration described above emits light from the light source unit 20 of the light source device 14, that is, illumination light that passes through the light guide 41 of the endoscope 12 and is emitted from the distal end portion 12d of the endoscope. Ls (see FIG. 5) has, for example, the emission spectrum LE shown in FIG.
Here, FIG. 6 is a graph showing an example of the emission spectrum of the light source section and the spectral sensitivity of the image sensor of the endoscope system of the first embodiment of the present invention, and FIG. 7 is the first embodiment of the present invention. 2 is a graph showing a wavelength shift due to a change in the amount of light in the emission spectrum of the light source unit of the endoscope system. FIG. 7 is a graph showing an enlarged range including the green color component Gc and the red color component Rc as color components with wavelengths of 450 nm to 700 nm in the emission spectrum LE of FIG.
In the emission spectrum LE shown in FIG. 6, symbol V indicates violet light, symbol B indicates blue light, symbol B indicates green light, and symbol R indicates red light. In the emission spectrum LE shown in FIG. 6, the solid line indicates a relatively low amount of light, and the broken line indicates a relatively high amount of light.

The emission spectrum LE shown in FIG. 6 has a peak wavelength near a wavelength of 400 nm and a peak wavelength near a wavelength of 450 nm. The peak wavelength around 400 nm is due to the violet light emitted by the additional light source 74 , and the peak wavelength around 450 nm is due to the blue light emitted by the second light source 72 .
The light with a wavelength of 470 nm to 700 nm is green light emitted by the first light source 71 and contains green and red as color components.

The emission spectrum LE shown in FIG. 6 shows nearly white light. In the endoscope system 10, the image sensor 48 having the spectral sensitivity characteristics shown in FIG. do. The symbol Bf shown in FIG. 6 indicates the spectral sensitivity to blue light. The symbol Gf indicates the spectral sensitivity to green light. The symbol Rf indicates the spectral sensitivity to red light. The spectral sensitivity Bf and the spectral sensitivity Gf have an overlapping wavelength range, and the spectral sensitivity Gf and the spectral sensitivity Rf have an overlapping wavelength range. The spectral sensitivity is not limited to these.

The image sensor 48 has the first element portion 48a, the second element portion 48b and the third element portion 48c as described above. For example, the first element portion 48a has a spectral sensitivity Gf for green light. The second element portion 48b has a spectral sensitivity Rf for red light. The third element portion 48c has a spectral sensitivity Bf for blue light.
Further, the first light source 71 may have a light emitting diode having an emission peak between the peak wavelength of the spectral sensitivity of the first element portion 48a and the peak wavelength of the spectral sensitivity of the second element portion 48b. In this case, if the first element portion 48a has a spectral sensitivity of Gf and the second element portion 48b has a spectral sensitivity of Rf, a light-emitting diode having an emission peak at a wavelength of 550 to 600 nm is used. If the first element portion 48a has a spectral sensitivity of Bf and the second element portion 48b has a spectral sensitivity of Gf, a light emitting diode having an emission peak at a wavelength of 450 to 550 nm is used.

Here, when the amount of light changes, the emission spectrum LE shifts in wavelength as shown in FIGS. In the emission spectrum LE shown in FIG. 6, since green light containing green and red color components is emitted from one first light source 71, the wavelength shift of the emission spectrum LE due to the change in the amount of light causes the emission spectrum LE to shift as shown in FIG. If the light quantity ratio between the green color component Gc and the red color component Rc changes, the light quantity ratio between the green color component Gc and the red color component Rc is no longer constant. As a result, in the image sensor 48, as shown in FIG. 8, the signal _ratio D1 between the signal value of red light and the signal value of green light is not constant and may deviate due to changes in the amount of light.
Due to this, by the light intensity change. The color of the endoscopic image of the observation target obtained through the image sensor 48 is shifted. That is, the white balance of the endoscopic image is lost. In order to suppress the shift in color due to changes in the amount of light and to keep the color constant regardless of the amount of light, the processor device 16 performs the following processing.
As for the green light and the blue light, there is no wavelength shift in the emission spectrum or the wavelength shift is small, and as shown in _FIG . is constant regardless of the amount of light.

The observation target is imaged using light emitted from at least one first light source 71 of the light source unit 20, and the processor unit 16 converts the first color component obtained by the first element unit 48a of the image sensor 48. A first signal value and a second signal value of the second color component obtained by the second element portion 48b are obtained. The processor device 16 determines a signal ratio between the first signal value and the second signal value, and by varying at least one signal value of the first signal value and the second signal value, the signal ratio is determined. Set to a predetermined set value.

In the image sensor 48, the first signal value of the first color component is obtained by the first element portion 48a, the second signal value of the second color component is obtained by the second element portion 48b, and the third signal value is obtained by the second element portion 48b. A third signal value of light of a color other than the two color components is obtained at the element portion 48c.
Then, the first signal value and the second signal value are output from the DSP 56 to the correction amount calculator 60 . By calculating the signal ratio between the first signal value and the second signal value in the correction amount calculator 60 and changing at least one of the first signal value and the second signal value, A signal ratio is set to a predetermined set value.
Further, by changing at least one signal value among the first signal value, the second signal value and the third signal value according to the amount of light, the signal ratio is set to a predetermined set value. can be In this case, the first signal value, the second signal value, or the third signal value to be changed according to the amount of light is determined, the value to be changed is obtained as a correction coefficient, and the correction coefficient is stored in the correction amount calculator 60 .

In the correction amount calculation unit 60, for example, with a preset value of the signal ratio set to ₁ , as shown in FIG. A correction coefficient for the signal value of red light or a correction coefficient for the signal value of green light that makes the signal ratio of 1 is 1, and the correction coefficient is stored in the correction amount calculator 60 . Then, the image processing unit 61 calls the correction coefficient from the correction amount calculation unit 60, and uses the correction coefficient to perform correction processing on the G image or the R image for one shooting frame. In this case, by changing the signal value of the red light or the signal value of the green light, it is possible to set the signal ratio to a preset value, for example, the signal ratio to 1, as described above.

Also, a luminance value is calculated using at least one of the first signal value and the second signal value, and the light amount of the first light source 71 is specified based on the luminance value. Then, the signal ratio may be set to a predetermined set value by changing at least one signal value of the first signal value and the second signal value according to the amount of light. In this case, the correction amount calculator 60 determines the first signal value or the second signal value to be changed according to the amount of light, obtains the value to be changed as a correction coefficient, and stores the correction coefficient in the correction amount calculator 60. Let

A luminance value is calculated using at least one of the first signal value, the second signal value, and the third signal value, and the light amount of the first light source 71 is specified based on the luminance value. Then, one of the first signal value, the second signal value, and the third signal value is set as a reference value, and the first signal value, the second signal value, and the third signal value are obtained according to the amount of light. The signal ratio may be set to a predetermined setting value by changing at least one signal value among the signal values of . Setting to such a set value is also called white balance processing.
In this case, the correction amount calculator 60 determines the first signal value, the second signal value, or the third signal value as the reference value, and changes the first signal value and the second signal value according to the amount of light. A value or a third signal value is determined, a value to be changed is obtained as a correction coefficient, and the correction coefficient is stored in the correction amount calculation unit 60 .
Although one signal value is used as the reference value in the above description, it is not limited to this. By changing at least one of the first signal value, the second signal value, and the third signal value according to the amount of light without setting a reference value, the signal ratio is set to a predetermined value. It may be set to a set value.

White balance processing can make the color of an endoscopic image constant regardless of the amount of light. The white balance processing will be described below. In this case, the image sensor 48 obtains the B signal, the G signal and the R signal of the endoscopic image as an example. Also, the G signal is used as a reference for white balance processing.

First, when the endoscope system is manufactured, the white plate is actually photographed at the reference light quantity point _P0 , and the signal ratio at the reference light quantity point _P0 , B( _P0 )/G( _P0 ), R(P ₀ )/G(P ₀ ). In this case, the signal ratio is a measured value.
The white balance gain at the reference light quantity point P ₀ is G(P ₀ )/B(P ₀ ), G(P ₀ )/R(P ₀ ), and the reciprocal of the signal ratio at the reference light quantity point P ₀ .

Furthermore, when the endoscope system is manufactured, the fluctuation rates Δ(B/G)(P) and Δ(R/G)(P) of the signal ratio due to the wavelength shift of the emission spectrum of the emission spectrum emitted from the scope due to changes in the amount of light are obtained.
A method for obtaining the fluctuation rates Δ(B/G)(P) and Δ(R/G)(P) of the signal ratio represented by the following equations is as follows.
First, at an arbitrary amount of light P, an actually measured signal ratio may be used directly using a white plate, or the wavelength shift of the emission spectrum of the illumination light Ls emitted from the light source unit 20 may be measured with a spectrometer. Alternatively, a signal ratio calculated using the known spectral sensitivity of the image sensor may be used. Note that the sensor signal can be obtained by integrating the spectral sensitivity of the image sensor and the emission spectrum.

However, Δ(B/G)(P ₀ )=1 and Δ(R/G)(P ₀ )=1.
The signal ratio at an arbitrary amount of light P is as follows.

As shown in the following equation, the reciprocal of the signal ratio at any light amount P is the light amount-dependent white balance gain.

Here, since the parts G(P ₀ )/B(P ₀ ) and G(P ₀ )/R(P ₀ ) in the above equations are white balance gains at the reference light quantity point P ₀ , the sensor signal The reciprocal Iv of the signal ratio variation rate, that is, Iv=1/(Δ(B/G)(P)), Iv=1/(Δ(R/G)(P)) is the light quantity dependent gain correction coefficient.

When the endoscope system is actually used, the white balance gain of the reference light amount point P0 and the light amount dependent gain correction _coefficient are stored in the correction amount calculator 60 of the endoscope system 10 . White balance processing is executed by multiplying the B signal and the R signal obtained by photographing the observation target by a light amount dependent gain correction coefficient.
When photographing a white plate, all signals at an arbitrary light amount P are adjusted to G(P).

A specific example of white balance processing for making the color of an endoscopic image constant regardless of the amount of light will be described. In this case, the image sensor 48 obtains the B signal, the G signal and the R signal of the endoscopic image as an example.
FIG. 9 is a graph showing an example of the wavelength shift due to changes in the amount of light in the emission spectrum of the light source unit of the endoscope system of the first embodiment of the present invention and the spectral sensitivity of the image sensor, and FIG. 4 is a graph showing an example of signal correction coefficients of the endoscope system of the embodiment of .

First, the signal values obtained when the white plate is irradiated with the illumination light Ls from the light source unit 20 at light amounts of 1, 0.5, and 0.01 are shown in Table 1 below. shall be However, at present, this signal value is unknown to an adjustment operator who performs white balance processing.

In order to perform the white balance processing, the adjustment operator should actually measure only the signal value with the white plate using the light quantity of 0.5 in Table 1 as the reference light quantity point. The signal values for light intensity 1 and light intensity 0.01 remain unknown to the adjustment operator. Next, the signal ratio is calculated from each signal with a light quantity of 0.5 in Table 1, and the reciprocal is taken to obtain the gain shown in Table 2 below. Of course, at this stage, gains for a light amount of 1 and a light amount of 0.01 are unknown.

Next, the emission spectrum LE shown in FIG. 9 is actually measured. Also, using the spectral sensitivity of the image sensor 48 shown in FIG. 9, the signal ratio for each amount of light is obtained. "B/G" in Table 3 below indicates the signal ratio between the B signal and the G signal, and "R/G" indicates the signal ratio between the R signal and the G signal. Although the signal values of the light amount 1 and the light amount 0.01 are unknown to the adjustment operator, the signal ratio of the light amount 1 and the light amount 0.01 can be clarified by this measurement. Emission spectrum measurement is a simpler method using only illumination light (not including imaging) than measurement using a white plate. Just do it.

Next, the signal ratio fluctuation rates Δ(B/G) and Δ(R/G) are calculated. The signal ratio fluctuation rate is normalized, for example, at the reference light quantity point P0 at which the light quantity is _0.5 .

Next, the light intensity dependent gain correction coefficients 1/(Δ(B/G)) and 1/(Δ(R/G)) are calculated. The light amount dependent gain correction coefficient is the reciprocal Iv of the signal ratio variation rate. Thereby, for example, the light quantity dependent gain correction coefficient can be obtained as shown in FIG. Reference G1 in FIG. 10 indicates the light intensity dependent gain correction coefficient ₁ /(Δ(B/G)), and reference G2 indicates the light intensity dependent gain correction coefficient ₁ /(Δ(R/G)).

Next, the light intensity dependent white balance gain is obtained by calculation. The light amount dependent white balance gain is the product of the above light amount dependent gain correction coefficient and the gain at the reference light amount point.

When the endoscope system is actually used, by multiplying the light amount dependent white balance gain in Table 6 obtained in the adjustment by the sensor signal at each light amount in Table 1 that the endoscope system will obtain during actual use, , the B signal, the G signal and the R signal obtained by the image sensor 48 can be white-balanced. Although the signal values for light intensity 1 and light intensity 0.01 in Tables 1 and 7 were not clear to the adjustment operator, the white balance of the signal value is certainly correct when actually using the endoscope system. will be taken. This makes it possible to perform white balance processing on an endoscopic image, obtain an endoscopic image with a constant color tone regardless of the amount of light, and enable more accurate diagnosis.

As shown in FIG. 6, the spectral sensitivity Bf and the spectral sensitivity Gf have an overlapping wavelength range, and the spectral sensitivity Gf and the spectral sensitivity Rf have an overlapping wavelength range. The narrower the range and the narrower the range of overlapping wavelengths, the more pure the endoscopic image without color mixture can be obtained. If the range of overlapping wavelengths is narrow, the above-mentioned signal ratio tends to deviate due to the wavelength shift of the emission spectrum, and the hue tends to change. However, even if the range of overlapping wavelengths is narrow, it is possible to make the color of the endoscopic image constant regardless of the amount of light by the above-described white balance processing. Even if the wavelength range of the spectral sensitivity of the image sensor 48 is narrow in this way, the white balance processing described above is effective.

Note that the configuration of the light source unit 20 is not limited to the configuration shown in FIG. 5 described above.
FIG. 11 is a schematic diagram showing a modified example of the light source section of the endoscope system according to the first embodiment of the present invention.
The light source unit 20 shown in FIG. 11 differs from the light source unit 20 shown in FIG. Detailed description is omitted.
The first light source 71 shown in FIG. 11 includes a light-emitting element 81a that emits excitation light, and fluorescence light that emits light containing two color components with different wavelengths when the excitation light emitted by the light-emitting element 81a is incident. body 81b.
In the first light source 71, for example, the excitation light emitted by the light emitting element 81a is blue light having a peak at about 445 nm, and the light emitted by the phosphor 81b is broadband light containing a red component in addition to the green component. Green light. Alternatively, the first light source 71 may emit broadband blue light containing a green component in addition to the blue component by changing the wavelength of the excitation light emitted by the light emitting element 81a and the phosphor 81b. .

[Second embodiment]
Next, a second embodiment will be described.
FIG. 12 is a schematic diagram showing an example of the light source section of the endoscope system according to the second embodiment of the present invention.
2nd Embodiment differs in the structure of a light source part. The light source unit 20 shown in FIG. 12 has the same configuration as the light source unit 20 shown in FIG. 5 except that the configuration of the light source is different from that of the light source unit 20 shown in FIG. do.

The light source section 20 shown in FIG. 12 has a third light source 75 . In the light source unit 20 shown in FIG. 5, light containing two color components having different wavelengths is emitted from the first light source 71. In the light source unit 20 shown in FIG. The third light source 75 emits light of the second color component as the third light.
A multiplexing member 79 is provided between the first light source 71 and the multiplexing member 77 . The multiplexing member 79 transmits the light emitted by the first light source 71 . The combining member 79 combines the light of the first color component emitted by the first light source 71 and the light of the second color component emitted by the third light source 75 and guides them to the combining member 77 . It is.
The first light source 71, the second light source 72, the third light source 75 and the additional light source 74 are each independently controllable.

The third light source 75 includes a light emitting element 88 that emits light of a second color component as third light, and a lens 89 that arranges the light emitted from the light emitting element 88 into parallel light or the like. The light emitting element 88 is, for example, a semiconductor element such as an LED or LD. The third light emitted from the third light source 75 is incident on the light guide 41 via the combining member 79 and the combining member 77 that transmit the third light.
A beam splitter 98 is provided between the third light source 75 and the combining member 79 . A part of the third light emitted by the third light source 75 is reflected by the beam splitter 98 at a predetermined rate. Light reflected by the beam splitter 98 is received by the photodetector 97 . The light source control unit 22 automatically and accurately controls the emission amount of the third light from the third light source 75 using the light amount detected by the photodetector 97 .
The wave combining member 79 has the same configuration as the wave combining member 76 and the wave combining member 77, and is, for example, a dichroic mirror or a dichroic prism.
The photodetector 97 has the same configuration as the photodetectors 91, 92, and 93 described above.

The light emitting element 81c of the first light source 71 emits, for example, green light as light of the first color component. The light emitting element 88 of the third light source 75 emits, for example, red light as the light of the second color component.
Further, the light emitting element 81c of the first light source 71 emits, for example, blue light as light of the first color component, and the light emitting element 88 of the third light source 75 emits, for example, light of the second color component, Green light may be emitted, and the second light source 72 may be configured to emit red light.

FIG. 13 is a graph showing an example of the emission spectrum of the light source unit and the spectral sensitivity of the image sensor of the endoscope system according to the second embodiment of the present invention, and FIG. FIG. 4 is a graph showing an example of signal ratio variation in an image sensor of a mirror system; FIG. In the emission spectrum LE shown in FIG. 13, the solid line indicates that the amount of light is relatively low. The dashed line indicates a relatively high amount of light.
In the emission spectrum LE and the spectral sensitivity of the image sensor 48 shown in FIG. 13, the same components as those of the emission spectrum LE and the spectral sensitivity of the image sensor 48 shown in FIG.

The spectral sensitivity of the image sensor 48 shown in FIG. 13 is the same as the spectral sensitivity of the image sensor 48 shown in FIG.
The emission spectrum LE shown in FIG. 13 differs from the emission spectrum LE shown in FIG. 6 in that it has a peak wavelength near a wavelength of 630 nm and that there is light with a wavelength of 500-600 nm. It is the same as the emission spectrum LE shown.
A peak wavelength around 630 nm is due to the red light emitted by the third light source 75 . Light with a wavelength of 500 to 600 nm is green light emitted by the first light source 71 .

The light source unit 20 shown in FIG. 13 also has a wavelength shift in the emission spectrum LE. For this reason, as shown in FIG. 14, the signal _ratio D1 between the signal value of red light and the signal value of green light is not constant and deviation occurs. Note that the signal ratio _D2 between the signal value of blue light and the signal value of green light is constant regardless of the amount of light.
Even in such a case, by obtaining the correction coefficient as described above, the signal ratio can be set to a predetermined set value, and the color tone of the endoscopic image can be kept constant regardless of the light intensity. be able to. In this way, when the wavelength shift of the emission spectrum LE occurs, the color of the endoscopic image can be made constant without being restricted by the configuration of the light source unit 20 .

The present invention is basically configured as described above. Although the endoscope system of the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

REFERENCE SIGNS LIST 10 endoscope system 12 endoscope 12a insertion portion 12b operation portion 12c bending portion 12d tip portion 12e angle knob 13a zoom operation portion 13b mode switching switch 14 light source device 16 processor device 17 universal cord 18 monitor 19 console 20 light source portion 21 light source Drive unit 22 Light source control unit 30a Illumination optical system 30b Photographing optical system 41 Light guide 45 Illumination lens 46 Objective lens 47 Zoom lens 48 Image sensor 48a First element unit 48b Second element unit 48c Third element unit 49 Pixel unit 49a first pixel 49b second pixel 49c third pixel 50 filter section 50B B color filter 50G G color filter 50R R color filter 50a first filter 50b second filter 50c third filter 54 image acquisition section 58 noise reduction section 59 conversion section 60 correction amount calculation unit 61 image processing unit 66 display control unit 69 control unit 71 first light source 72 second light source 74 additional light source 75 third light source 76 wave combining member 77 wave combining member 78 lens 79 wave combining member 81, 81a, 81b, 81c, 83, 86, 88 light emitting element 82, 84, 87, 89 lens 91, 92, 93, 97 photodetector 94, 95, 96, 98 beam splitter Bf, _Gf , Rf spectral sensitivity D1, D ₂ signal ratio G ₁ , G ₂ light amount dependent gain correction coefficient Gc Green color component LE Emission spectrum Lr Reflected light Ld Distance Ls Illumination light Ob Object Rc Red color component

Claims (11)

a light source unit including at least one first light source that emits light containing two color components having different wavelengths;
an image sensor having at least a first element portion having spectral sensitivity to the first color component and a second element portion having spectral sensitivity to the second color component of the two color components of the first light source; ,
The light emitted from at least one of the first light sources of the light source unit is used to image an observation target, and the first color component of the first color component obtained by the first element unit of the image sensor is obtained. a signal value; and a processor for obtaining a second signal value of the second color component obtained by the second element unit;
the image sensor has a range in which the spectral sensitivity of the first element portion and the spectral sensitivity of the second element portion overlap;
The light source unit has one first light source and one second light source that emits light of a color other than the two color components,
The image sensor has a third element unit having spectral sensitivity to the light of a color other than the two color components,
The processor receives the first signal value, the second signal value, and the obtaining a third signal value of the light of a color other than the two color components, and luminance from at least one of the first signal value, the second signal value and the third signal value of the image sensor; and determining the amount of light of the first light source based on the luminance value, and selecting one of the first signal value, the second signal value, and the third signal value according to the amount of light. , an endoscope system for setting a signal ratio between said first signal value and said second signal value to a predetermined set value by varying at least one signal value. a light source unit including at least one first light source that emits light containing two color components having different wavelengths;
an image sensor having at least a first element portion having spectral sensitivity to the first color component and a second element portion having spectral sensitivity to the second color component of the two color components of the first light source; ,
The light emitted from at least one of the first light sources of the light source unit is used to image an observation target, and the first color component of the first color component obtained by the first element unit of the image sensor is obtained. a signal value; and a processor for obtaining a second signal value of the second color component obtained by the second element unit;
the image sensor has a range in which the spectral sensitivity of the first element portion and the spectral sensitivity of the second element portion overlap;
The light source unit has one first light source and one second light source that emits light of a color other than the two color components,
The image sensor has a third element unit having spectral sensitivity to the light of a color other than the two color components,
The processor receives the first signal value, the second signal value, and the obtaining a third signal value for the light of a color other than the two color components;
The processor calculates a brightness value from at least one of the first signal value, the second signal value, and the third signal value of the image sensor, and calculates the brightness value based on the brightness value, the first light source to determine the amount of light in the
one of the first signal value, the second signal value, and the third signal value is used as a reference value, and the first signal value and the second signal value are obtained according to the amount of light; setting a signal ratio between the first signal value and the second signal value to a predetermined set value by changing at least one signal value among the value and the third signal value; optic system. a light source unit including at least one first light source that emits light containing two color components having different wavelengths;
an image sensor having at least a first element portion having spectral sensitivity to the first color component and a second element portion having spectral sensitivity to the second color component of the two color components of the first light source; ,
The light emitted from at least one of the first light sources of the light source unit is used to image an observation target, and the first color component of the first color component obtained by the first element unit of the image sensor is obtained. a signal value; and a processor for obtaining a second signal value of the second color component obtained by the second element unit;
the image sensor has a range in which the spectral sensitivity of the first element portion and the spectral sensitivity of the second element portion overlap;
The light source unit has one first light source and one second light source that emits light of a color other than the two color components,
The image sensor has a third element unit having spectral sensitivity to the light of a color other than the two color components,
The processor obtains a third signal value of the light of a color other than the two color components obtained by the third element portion of the image sensor.
The processor receives the first signal value, the second signal value, and the obtaining the third signal value, the processor calculates a luminance value from at least one of the first signal value, the second signal value and the third signal value of the image sensor; specifying the amount of light of the first light source based on the value, and determining at least one signal value among the first signal value, the second signal value, and the third signal value according to the amount of light. The endoscope system, wherein the signal ratio between the first signal value and the second signal value is set to a predetermined set value by changing. a light source unit including at least one first light source that emits light containing two color components having different wavelengths;
an image sensor having at least a first element portion having spectral sensitivity to the first color component and a second element portion having spectral sensitivity to the second color component of the two color components of the first light source; ,
The light emitted from at least one of the first light sources of the light source unit is used to image an observation target, and the first color component of the first color component obtained by the first element unit of the image sensor is obtained. a signal value; and a processor for obtaining a second signal value of the second color component obtained by the second element unit;
the image sensor has a range in which the spectral sensitivity of the first element portion and the spectral sensitivity of the second element portion overlap;
The light source unit has one first light source and one second light source that emits light of a color other than the two color components,
The image sensor has a third element unit having spectral sensitivity to the light of a color other than the two color components,
The processor obtains a third signal value of the light of a color other than the two color components obtained by the third element unit, and the first element unit of the image sensor, the Obtaining the first signal value, the second signal value, and the third signal value respectively obtained by the second element unit and the third element unit, the processor obtains the image sensor calculating a luminance value from at least one of the first signal value, the second signal value and the third signal value of, and based on the luminance value, specifying the amount of light of the first light source;
one of the first signal value, the second signal value, and the third signal value is used as a reference value, and the first signal value and the second signal value are obtained according to the amount of light; setting a signal ratio between the first signal value and the second signal value to a predetermined setting value by changing at least one signal value among the value and the third signal value; optic system. the light having a color other than the two color components is light exhibiting blue color;
5. The endoscope system according to claim 3, wherein said first color component of said two color components is green and said second color component is red. the light having a color other than the two color components is light exhibiting red color;
5. The endoscope system according to claim 3, wherein said first color component of said two color components is blue and said second color component is green. The light source unit emits light containing the first color component representing green and the second color component representing red, or the first color component representing blue and green light as the first light source. 5. The endoscope system according to any one of claims 1 to 4, further comprising a light source that emits light containing the second color component that indicates . The light source unit includes, as the first light source, a light source that emits light containing the first color component representing green and the second color component representing red, the first color component representing blue, and green 5. The endoscope system according to any one of claims 1 to 4, further comprising a light source that emits light containing the second color component that indicates . 9. The first light source comprises a light-emitting element that emits excitation light, and a phosphor that emits the light containing the first color component and the second color component by the excitation light. 1. The endoscope system according to claim 1. The endoscope system according to any one of claims 1 to 8, wherein said first light source comprises a light emitting diode having an emission spectrum including said first color component and said second color component. 11. The first light source according to claim 10, comprising a light-emitting diode having an emission peak between a peak wavelength of spectral sensitivity of said first element portion and a peak wavelength of spectral sensitivity of said second element portion. endoscope system.

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