JP2019122865A - Endoscope light source device, endoscope system, and method of operating endoscope light source device - Google Patents

Abstract

To provide an endoscope light source device, an endoscope system, and a method of operating endoscope light source device capable of adjusting the contrast of a blood vessel freely according to the depth and thickness under a mucosa.SOLUTION: A first light source 20a emits V-light, or violet light having a depth resolution, to an under-mucosa blood vessel to be observed. A second light source 20b emits B-light, or blue light, and fluorescent light obtained by irradiating a phosphor with the B-light as excitation light. A Bs-light and Gn-light generation band restriction filter 225 allows Bs-light, or blue narrow-band light, and Gn-light, or green narrow-band light having thickness resolution for blood vessel, of the light emitted from the second light source to at least transmit therethrough. A light amount ratio setting unit 23 sets a light amount ratio between the V-light and the Bs-light such that a contrast of the blood vessel to the mucosa becomes a target contrast corresponding to the depth and thickness of the blood vessel. A light source control unit 22 controls the first light source 20a and the second light source 20b using the light amount ratio set by the light amount ratio setting unit.SELECTED DRAWING: Figure 17

Description

  The present invention relates to an endoscope light source device, an endoscope system, and an operating method of the endoscope light source device, in which illumination light to be irradiated to an observation object is formed using a plurality of light sources.

  In the medical field, diagnosis using an endoscope system including an endoscope light source device, an endoscope, and a processor device is widely performed. The endoscope light source device is a device that generates light (hereinafter referred to as illumination light) to be irradiated to an observation target such as a mucous membrane of a body cavity. Conventionally, xenon lamps have been used as endoscope light source devices, but in recent years semiconductors such as light emitting diodes (LEDs) and laser diodes (hereinafter referred to as LDs (laser diodes)) have been used instead of xenon lamps. Light sources are being used.

  For example, in the endoscope systems of Patent Document 1 and Patent Document 2, two LDs of LD1 and LD2 are mounted on an endoscope light source device, and laser light emitted from these LDs is used as a phosphor (wavelength conversion member) By passing through, the observation target is irradiated with white light which is formed by the laser light transmitted through the phosphor and the fluorescence emitted from the phosphor. In particular, in Patent Document 1, an image of contrast suitable for diagnosis can be obtained by changing the component of white light by adjusting the light amount ratio of LD 1 and LD 2. Moreover, in the endoscope system of Patent Document 2, it is described that the contrast (brightness ratio) of the blood vessel and the mucous membrane is changed by adjusting the light amount ratio of the LD1 and the LD2, and the contrast of the blood vessel and the mucous membrane is 1. By setting the light amount ratio between LD1 and LD2 so as to be 6 or more, the ability to extract blood vessels located at relatively shallow positions under the mucous membrane (hereinafter referred to as superficial blood vessels) can be obtained.

  The endoscope system of Patent Document 3 utilizes an LED emitting purple light and a white light source emitting white light by combining an LED emitting blue light and a phosphor. Then, an observation mode in which observation is performed using white light by, for example, inserting and removing dichroic mirrors disposed in these optical paths, and an observation mode in which observation is performed using light of purple light and a part of white light Switching.

  Further, in recent years, an endoscope system capable of so-called narrow-band light observation has also become widespread, which makes it easier to observe the presence or absence of a blood vessel and a traveling pattern than when white light is irradiated. In narrow band light observation, for example, a narrow band light (hereinafter referred to as a blue narrow band light) of a blue wavelength band from white light of a xenon lamp using a band limit filter for wide band light which limits the wavelength band of wide band light The narrow band light of the wavelength band (hereinafter referred to as green narrow band light) is generated. And the image which made it easy to observe a blood vessel is provided by using combining the signal obtained by imaging an observation object with blue narrow band light, and the signal obtained by imaging an observation object with green narrow band light.

JP, 2013-034753, A JP, 2012-105784, A International Publication No. 2012/101904

  The light source used in the endoscope system is being replaced with a semiconductor light source from a xenon lamp, but the white light emitted by a xenon lamp etc. and the white light generated by a semiconductor light source are each spectral spectrum Are different. For this reason, according to the depth and the thickness of the submucosa, blood vessels are observed in the case where the observation target is irradiated with the conventional white light by a xenon lamp etc. and in the case where the observation target is irradiated with white light by the semiconductor light source. There is a difference in ease.

  For example, focusing on blood vessels of a certain depth and thickness below the mucous membrane, using a semiconductor light source is higher in contrast to the mucous membrane and easier to observe than using a xenon lamp. Focusing on blood vessels of large size and thickness, using a semiconductor light source rather than using a xenon lamp may result in low contrast to the mucous membrane, making it difficult to observe. The difference in the appearance of the blood vessel caused by the difference in the spectrum of the xenon lamp and the semiconductor light source is particularly noticeable when narrow-band light observation is performed to emphasize the blood vessel. Therefore, if a doctor who used an endoscope system that uses a xenon lamp uses the endoscope system that uses a semiconductor light source, he may be confused because of the difference in how blood vessels look like the above. In an endoscope system using a semiconductor light source, it is desired to reproduce the same view of blood vessels as in the case of using a xenon lamp, in particular, a blood vessel of narrow band observation for generating blue narrow band light and green narrow band light from white light of the xenon lamp There is a demand to reproduce the appearance of

  On the other hand, there is also a demand for better observation of blood vessels of depth and thickness, which were difficult to observe with a xenon lamp, in order to make a more accurate and detailed diagnosis. When a semiconductor light source is used, due to the difference in spectrum from the xenon lamp, blood vessels that were difficult to observe with the xenon lamp may be able to be observed well. The same applies to narrowband light observation. That is, it is desirable to take advantage of the advantages of using a semiconductor light source.

  Therefore, in order to meet the above two demands, in the endoscope system using a semiconductor light source, the contrast of the blood vessel can be freely adjusted and observed according to the depth and thickness of the blood vessel under the mucous membrane. Is desirable. The present invention provides an endoscope light source device, an endoscope system, and an operating method of the endoscope light source device capable of freely adjusting the contrast of a blood vessel in accordance with the submucosal depth and thickness. With the goal.

  In the endoscope light source device of the present invention, a first light source for emitting V light which is violet light having depth resolution, B light which is blue light, and excitation for a blood vessel under the mucous membrane to be observed The second light source that emits fluorescence obtained by irradiating the phosphor with B light as light and Bs light, which is blue narrow band light among the light emitted from the second light source, and thickness resolution for blood vessels The band limiting filter for generating Bs light and Gn light that transmits at least Gn light, which is green narrow band light, the light amount ratio of V light to Bs light is set, the blood vessel contrast to the mucous membrane, the blood vessel depth and And a light source control unit configured to control the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit.

  Preferably, the peak wavelength of V light is shorter than the peak of the absorption spectrum of hemoglobin, and the peak wavelength of Bs light is longer than the peak of the absorption spectrum of hemoglobin. It is preferable that the light amount ratio setting unit sets the light amount ratio by setting the contrast of the blood vessel when irradiating the Bs light to the observation target as the target contrast. The light amount ratio setting unit may set the light amount ratio to equalize the balance of contrast of a plurality of blood vessels having the same depth in the submucosa and different in thickness with the balance when irradiating the Bs light to the observation target preferable. The light amount ratio setting unit may set the light amount ratio to equalize the balance of contrast of a plurality of blood vessels having different depths under the mucous membrane and equal in thickness to the balance in the case of irradiating the Bs light to the observation target. preferable. It is preferable that the light amount ratio setting unit sets the light amount ratio that makes the size of the blood vessel contrast equal to the size of the blood vessel contrast when irradiating the Bs light to the observation target.

  Based on the contrast of the blood vessel when the Bs light is irradiated to the observation target, the light quantity ratio setting unit sets the ratio or difference of the contrast of a plurality of blood vessels having the same depth in the submucosa and different in thickness to the Bs light It is preferable to set the light amount ratio to be larger than the contrast ratio or the difference in the case of irradiating. Based on the contrast of the blood vessel when the Bs light is irradiated to the observation target, the light quantity ratio setting unit sets the ratio or difference of the contrast of a plurality of blood vessels having different depths under the mucous membrane and having the same thickness to the Bs light It is preferable to set the light amount ratio to be larger than the contrast ratio or the difference in the case of irradiating.

  The light source control unit preferably controls the light emission amounts of the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit. Preferably, the light amount ratio setting unit controls the light emission time of the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit. The light source control unit preferably controls both the light emission amount and the light emission time of the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit.

  Preferably, the first light source is a V-LED that emits V light, and the second light source includes a B-LED that emits B light, and a phosphor. The fluorescence preferably includes green light G light and red light R light.

  In the endoscope system of the present invention, a first light source that emits V light, which is violet light having depth resolution, and B light, which is blue light, and excitation light for blood vessels under the mucous membrane to be observed And Bs light, which is a blue narrow band light of the light emitted from the second light source, and has a thickness resolution with respect to blood vessels. Set the band limiting filter for Bs light and Gn light generation that transmits at least Gn light that is green narrow band light, and set the light amount ratio of V light and Bs light, and contrast the blood vessels to the mucous membranes A light amount ratio setting unit for setting a target contrast according to the length, a light source control unit for controlling the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit, an imaging sensor for imaging an observation target; Equipped with

  The present invention provides a first light source for emitting V light which is violet light having depth resolution, B light which is blue light, and B light as excitation light for blood vessels under the mucous membrane to be observed Among the light emitted from the second light source, the second light source emitting fluorescence obtained by irradiating the phosphor, Bs light which is blue narrow band light, and the green narrow band light having thickness resolution with respect to the blood vessel In the operating method of an endoscope light source apparatus including a Bs light and a Gn light generation band-limiting filter that transmits at least a Gn light, the light amount ratio setting unit sets a light amount ratio of V light to Bs light And the light source control unit controls the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit.

  According to the present invention, the contrast of blood vessels can be freely adjusted according to the submucosal depth and thickness.

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 light which a light source emits. It is a graph which shows the spectrum of illumination light. It is explanatory drawing which shows the depth of the blood vessel with respect to a mucous membrane, and the thickness of the blood vessel. It is a graph which shows the reflectance of the mucous membrane and several blood vessels from which depth and thickness differ. It is a graph which shows how to calculate the brightness to a mucous membrane. It is a graph which shows the brightness of the blood vessel obtained when irradiating purple light. It is a graph which shows the contrast of the blood vessel obtained when irradiating purple light. It is the graph which rearranged the graph which shows the contrast of the blood vessel obtained when irradiating with purple light in order of the depth for every same depth. It is a graph which shows the brightness of the blood vessel obtained when irradiating blue light. It is a graph which shows the contrast of the blood vessel obtained when irradiating blue light. It is the graph which rearranged the graph which shows the contrast of the blood vessel obtained in the case of irradiating blue light in order of the depth for every same depth. It is a schematic diagram which shows the relationship between the absorption spectrum of hemoglobin, and the purple light and blue light which are used for illumination light. It is a graph which shows the spectral characteristic of a color filter. It is a graph which shows the balance of the contrast of the blood vessel obtained when various light quantity ratios are set. It is a block diagram of an endoscope system of a 2nd embodiment which carries out narrow band light observation. It is a graph which shows the spectrum of illumination light which the endoscope system of a 2nd embodiment uses. It is a graph which shows the spectrum of the illumination light which the conventional endoscope system which performs narrow band light observation uses. It is a graph of the spectrum of blue narrow band light. It is a graph which shows the contrast of the blood vessel obtained by the conventional blue narrow band light. Fig. 5 is a graph showing the contrast ratio of blood vessels to a conventional endoscopic system. It is a graph which shows the contrast ratio between the blood vessels in which the submucosal depth is equal and thickness differs. It is a graph which shows the contrast ratio between blood vessels of equal thickness and different submucosal depths. FIG. 6 is a schematic view of a band limiting filter used when sequentially generating two types of narrow band light. FIG. 1 is a schematic view of a capsule endoscope.

First Embodiment
As shown in FIG. 1, the endoscope system 10 includes an endoscope 12, an endoscope light source device 14, a processor device 16, a monitor 18, and a console 19. The endoscope 12 is optically connected to the endoscope 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 curved portion 12c provided at the distal end side of the insertion portion 12a, and a distal end portion It has 12d. By operating the angle knob 12e of the operation portion 12b, the bending portion 12c performs a bending operation. By this bending operation, the tip 12d is directed in a desired direction. In addition to the angle knob 12e, the operation unit 12b is provided with a zoom operation unit 13 and the like.

  The processor unit 16 is electrically connected to the monitor 18 and the console 19. The monitor 18 outputs and displays an image of each observation mode, image information attached to the image, and the like. The console 19 functions as a user interface that receives an input operation such as function setting. The processor 16 may be connected with an external recording unit (not shown) for recording an image, image information, and the like.

  As shown in FIG. 2, the endoscope light source device 14 is a device that generates illumination light for irradiating an observation target, and is a light source control that controls the light source unit 20 having a plurality of light sources and each light source of the light source unit 20 A light quantity ratio setting part 23 for setting a light quantity ratio of a plurality of light sources, and an optical path coupling part 24 for coupling an optical path of light emitted from the light source part 20 are provided.

  The light source unit 20 includes two types of a first light source 20a that emits light in a first wavelength band and a second light source 20b that emits light in a second wavelength band that has a continuous spectrum wider than that of the first wavelength band. It has a light source. The first light source 20 a is a violet LED (hereinafter referred to as a V-LED (Violet Light Emitting Diode)). The second light source 20b generates fluorescence from the green wavelength band to the red wavelength band by the blue LED (hereinafter referred to as B-LED (Blue Light Emitting Diode)) and the blue light emitted by the B-LED (hereinafter referred to as B light) White light is generated by the B light transmitted through the phosphor and the fluorescence emitted by the phosphor.

  As shown in FIG. 3, the V-LED constituting the first light source 20 a is a violet light source that emits violet light (hereinafter referred to as V light) having a center wavelength of 415 nm and a wavelength band of about 400 to 430 nm. In the present embodiment, the central wavelength of the V-LED is 415 nm, but a V-LED having a central wavelength of about 400 to 430 nm can be used. The B-LED constituting the second light source 20b is a blue light source that emits blue light (hereinafter referred to as B light) having a central wavelength of 450 nm and a wavelength band of 430 to 470 nm, and the phosphor constituting the second light source 20b is B The irradiation of light emits fluorescence having a wavelength band ranging from 480 to 650 nm. Therefore, the fluorescence emitted by the phosphor includes green light having a wavelength band of about 480 to 600 nm (hereinafter referred to as G light) and red light having a wavelength band of about 600 nm to 680 nm (hereinafter referred to as R light). . Therefore, the light emitted from the second light source 20b emits white light composed of B light passing through the phosphor and G light and R light including fluorescence generated by the phosphor when the B light is irradiated as excitation light. . Although the details will be described later, the light of the first wavelength band emitted by the first light source 20a is V light, and the first wavelength band is a violet wavelength band corresponding to V light. The light of the second wavelength band emitted by the second light source 20b is white light, and the second wavelength band is the wavelength band of B light to R light.

  The center wavelength of the V-LED and the B-LED has a width of about ± 5 nm to about ± 10 nm. The center wavelength is a wavelength substantially at the center of the wavelength band, and depending on the shape of the spectrum, the wavelength corresponding to the peak of the spectrum (hereinafter, referred to as peak wavelength) may not coincide with the center wavelength. The V light used in the endoscope system 10 may have different center wavelengths and peak wavelengths, and the center wavelengths and peak wavelengths may be substantially the same. The center wavelength and the peak wavelength of the V light in the present embodiment substantially coincide with each other. Similarly, the B light used in the endoscope system 10 may have different center wavelengths and peak wavelengths, and the center wavelengths and peak wavelengths may be substantially the same. The central wavelength and peak wavelength of the B light in the present embodiment are substantially the same.

  Of the B light and G light emitted by the B-LED constituting the second light source 20b, light with a wavelength of about 450 nm to about 500 nm lowers the contrast of fine structures such as surface blood vessels and pit patterns. In the optical path of the second light source 20b, a band limiting filter (first band limiting filter, hereinafter referred to as a band limiting filter for Bs light generation) 25 for reducing light in the wavelength band of about 450 nm to about 500 nm. It is arranged. For this reason, the band limiting filter 25 for Bs light generation mainly includes blue light (hereinafter referred to as Bs light) and green light (hereinafter, referred to as Bs light) in which components in the wavelength band of about 450 nm to about 500 nm are reduced from white light emitted by the second light source 20b. Hereinafter, this is called Gs light). The peak wavelength of Bs light is about 440 nm to 450 nm, and Bs light is light of a third wavelength band generated from light of a second wavelength band (white light). The Bs light, the V light, the Gs light, and the R light are mixed by the optical path coupling unit 24 to become the illumination light 26 shown in FIG.

  That is, the light source unit 20 emits illumination light 26 having a spectrum in which V light, Bs light, Gs light, and R light are superimposed by a plurality of light sources that independently emit light of these different colors. Since the light emission amount (hereinafter simply referred to as light amount) and the length of light emission time of the first light source 20a and the second light source 20b can be independently controlled, the spectrum of the illumination light is the first light source 20a and the second light source. It can change by changing the light quantity of the light source 20b, the length of light emission time, etc.

  The light source control unit 22 uses the light amount ratio set by the light amount ratio setting unit 23 to drive the drive current, drive voltage, and drive current of the V-LED configuring the first light source 20a and the B-LED configuring the second light source 20b. Or control the drive voltage. Specifically, the light emission timing and the light amount of the V light emitted by the first light source 20a and the white light emitted by the second light source 20b by individually controlling the pulse width and pulse length of the control pulse input to each LED , Control the length of light emission time, etc. Thereby, the light source control unit 22 changes the substantial spectrum of the illumination light. In the present embodiment, the light source control unit 22 controls the light amounts of the V-LEDs constituting the first light source 20a and the B-LEDs constituting the second light source 20b.

  The light amount ratio setting unit 23 sets the light amount ratio of the V light and the Bs light to the light source control unit 22. Specifically, the light amount ratio setting unit 23 sets the light amount of V light emitted by the V-LED of the first light source 20a and the light amount of B light emitted by the B-LED of the second light source 20b to perform illumination. The light amounts of V light and Bs light included in the light 26 are set. That is, the light quantity ratio set by the light quantity ratio setting unit 23 is a control parameter of the V-LED constituting the first light source 20a and the B-LED constituting the second light source 20b, and the light emission time of these is taken into consideration Is a substantial light amount ratio (a light amount ratio in a broad sense). In the present embodiment, the light source control unit 22 makes the light emission time lengths of the first light source 20a and the second light source 20b the same, and controls the ratio of the light emission amount per unit time (light amount ratio in a narrow sense). For this reason, the light amount ratio setting unit 23 sets the light emission amount per unit time of the V-LED constituting the first light source 20a and the B-LED constituting the second light source 20b in accordance with the control method of the light source control unit 22. The ratio is set as the light amount ratio.

  The light quantity ratio setting unit 23 has at least light of a first wavelength band having depth resolution with respect to blood vessels under the observation target mucous membrane and thickness resolution with respect to blood vessels of the same depth under the mucous membrane. The light amount ratio of the light of the third wavelength band is set to the light source control unit 22. That is, the light amount ratio setting unit 23 sets the light amount ratio of the V light and the Bs light. Thereby, the light quantity ratio setting unit 23 sets the contrast of the blood vessel to the mucous membrane to the target contrast according to the depth and the thickness of the blood vessel.

  The target contrast is a target of balance of contrast to the mucous membranes of a plurality of blood vessels having different depths and thicknesses, and corresponds one-to-one with the light amount ratio set by the light amount ratio setting unit 23. Although a plurality of light quantity ratios and target contrasts are preset in the light quantity ratio setting unit 23, the setting can be arbitrarily selected or changed using input devices such as the operation unit 12b and the console 19.

  Depth resolution refers to the fact that the contrast to the mucous membrane changes with the depth of the blood vessel from the mucosal surface, and the depth can be identified by the change in the contrast to the mucous membrane. The thickness resolution means that the contrast with respect to the mucous membrane is changed by the thickness of the blood vessel, and the thickness of the blood vessel can be identified by the change in the contrast with respect to the mucous membrane.

  As shown in FIG. 5, when the distance from the observation target mucous membrane to the upper end of the blood vessel (the point closest to the mucous membrane) is the blood vessel depth "d" μm and the blood vessel diameter is the blood vessel thickness "φ" μm The graph which calculated the reflectance of the mucous membrane and the several blood vessel from which depth and thickness differ by simulation is FIG. In FIG. 6 and the following, the depth from the mucosal surface is represented by “d” as a numerical value, and the thickness of the blood vessel is represented as “φ” as a numerical value. For example, a blood vessel having a depth of 5 μm and a diameter of 20 μm is represented by “d5φ20”. The same is true for blood vessels of other depths and thicknesses, and in FIG. 6, blood vessels of d5.phi. 40 (depth 5 .mu.m diameter 40 .mu.m), d15 .phi. 20 (depth 15 .mu.m diameter 20 .mu.m) blood vessels, d50 .phi. The graph of each reflectance of the blood vessel of 50 μm in diameter and 10 μm in diameter, and the blood vessel of d50φ 20 (depth of 50 μm in diameter and 20 μm) is shown.

  As can be seen from FIG. 6, in the graph of the reflectance of a plurality of blood vessels having different depths and thicknesses, in the wavelength band of about 450 nm or less, even if the thicknesses “φ” are different, the depth “d” is the same. The values of the reflectance converge to approximately the same reflectance and differ depending on the difference in depth "d". And, the lower the submucosal blood vessels, the lower the reflectance, and the lower the submucosal blood vessels, the higher the reflectance and the closer to the mucosal reflectance. The contrast of the blood vessel is, for example, the ratio (or difference) between the reflectance of the mucous membrane and the reflectance of the blood vessel, and the larger the difference in brightness to the mucous membrane, the higher the visibility. Therefore, when imaging the observation target by irradiating light of about 450 nm or less, the blood vessel with a depth of 5 μm (d5) has the lowest reflectance among the blood vessels whose reflectance is shown in FIG. Therefore, the contrast to the mucous membrane is high and the visibility is good. Conversely, a blood vessel having a depth of 50 μm (d50) is most reflective near the mucous membrane and is a bright blood vessel, so the contrast to the mucous membrane is low and the visibility is the worst. Therefore, when light of a wavelength band of about 450 nm or less is irradiated to image an observation target, contrast is obtained depending on the depth of the blood vessel, regardless of the thickness of the blood vessel. And when blood vessels of different depths are compared, the blood vessel contrast differs depending on the blood vessel depth. Therefore, light in a wavelength band of about 450 nm or less has depth resolution for a plurality of blood vessels having different depths and thicknesses.

  On the other hand, in the wavelength band of about 450 nm to 600 nm, even if the depth "d" is different, when the thickness "φ" is the same, it converges to substantially the same reflectance, and the difference in the thickness "φ" The value of the reflectance which converges by differs. The thicker the blood vessel, the lower the reflectance, and the thinner the blood vessel, the higher the reflectance and the closer to the reflectance of the mucous membrane. Therefore, when imaging the observation target by irradiating light of about 450 nm or less, the blood vessel with a thickness of 40 μm (φ 40) has the lowest reflectance among the blood vessels whose reflectance is shown in FIG. Therefore, the contrast to the mucous membrane is high and the visibility is good. On the other hand, blood vessels with a thickness of 10 μm (φ 10) are the most reflective to the mucous membrane, and are bright, and therefore the contrast to the mucous membrane is low and the visibility is the worst. Therefore, when light of a wavelength band of approximately 450 nm or more and 600 nm or less is irradiated to image an observation target, contrast is obtained depending on the thickness of the blood vessel, regardless of the depth of the blood vessel. And when blood vessels of different thicknesses are compared, the contrast of the blood vessels is different depending on the thickness of the blood vessels. Therefore, light in a wavelength band of approximately 450 nm to 600 nm has a resolution of thickness for blood vessels having different depths and thicknesses.

  According to FIG. 6, the light in the wavelength band of approximately 600 nm or more has a reflectance of all the blood vessels close to the reflectance of the mucous membrane regardless of the depth and thickness of the blood vessel, so the wavelength band of 600 nm or more It is understood that blood vessels are difficult to observe even if the observation target is imaged by irradiating the light of.

  As shown in FIG. 7, when the light of wavelength 415 nm is irradiated, the brightness of the d5φ20 blood vessel with respect to the mucous membrane is “d5φ20 blood vessel reflectivity R1 / mucous membrane reflectivity R0” using the graph of FIG. Alternatively, it is determined by the reflectance R1 of the blood vessel of d5φ20, the reflectance R0 of the mucous membrane, and the brightness to the mucosa of the blood vessel of d5φ20 when the wavelength 450 nm is irradiated, “the reflectance R3 of the blood vessel of d5φ20 / reflectance R2 of the mucosa (Or, the reflectance R3 of the blood vessel of d5φ 20, the reflectance R2 of the mucous membrane). Therefore, the ratio (or difference) of the value integrated in the wavelength band of the light to which the reflectance of the blood vessel is integrated to the value integrated in the wavelength band of the light to which the reflectance of the mucous membrane is the brightness of the blood vessel relative to the mucous membrane. And the reciprocal of the brightness of the blood vessel to the mucous membrane represents the contrast of the blood vessel.

  When V light is irradiated, the brightness with respect to the mucous membrane of a plurality of blood vessels different in depth and thickness is as shown in FIG. Further, in the case of irradiating V light, the contrasts of a plurality of blood vessels having different depths and thicknesses are as shown in FIG. According to the bar graph of FIG. 9, the contrasts of blood vessels having different depths and thicknesses at the time of V light irradiation have nearly equal values if the depths are equal. Further, as can be seen from FIG. 10 in which the bar graphs of FIG. 9 are rearranged in order of depth in the φ20 group and the φ40 group, when blood vessels of the same thickness are compared, the shallower the submucosa is The higher the position, the lower the contrast to the mucous membrane. Thus, V-light has depth resolution. In the present embodiment, the first wavelength band having depth resolution is a violet wavelength band corresponding to V light.

  Bs light is light having a wavelength band near 450 nm, and is located at the boundary between the wavelength band on the short wavelength side having depth resolution and the wavelength band on the long wavelength side having thickness resolution. Is expected to have the transient nature of (see FIG. 6). In order to investigate the characteristics of the Bs light, the brightness of the mucous membranes of a plurality of blood vessels having different depths and thicknesses is calculated in the same manner as the V light, and a bar graph is shown in FIG. And the graph which represented the contrast to the mucous membrane of a plurality of blood vessels which differ in depth and thickness in a group by every blood vessel depth and was represented by a bar graph in thickness order is FIG. The graph represented by the bar graph in order of depth is FIG.

  As can be seen from FIG. 12, when contrast is compared with the mucous membranes of blood vessels which are at the same depth under the mucous membrane, when the Bs light is irradiated, the thicker the blood vessel, the higher the contrast to the mucous membrane. That is, Bs light has thickness resolution for blood vessels at the same depth below the mucous membrane. Therefore, in the present embodiment, the light of the third wavelength band having thickness resolution for blood vessels at the same depth under the mucous membrane is Bs light, and the third wavelength band is the blue wavelength corresponding to the Bs light It is a band.

  As can be seen from FIG. 13, when the Bs light is irradiated, the contrast with the mucous membranes of the same thickness but different depths is compared. The more blood vessels there are, the lower the contrast to the mucosa. Thus, Bs light has depth resolution for blood vessels of the same thickness.

  Also, as shown in FIG. 14, the peak of the absorption spectrum of hemoglobin is at about 420 nm to about 430 nm. The peak wavelength of V light (light in the first wavelength band) is on the short wavelength side of the peak of the absorption spectrum of hemoglobin, and the peak wavelength of Bs light (light in the third wavelength band) is hemoglobin It is on the longer wavelength side than the peak of the absorption spectrum. And if the light quantity in each peak wavelength of V light and Bs light is equal, the absorption intensity of hemoglobin will become the same grade. For this reason, the depth resolution of V light and the thickness resolution for blood vessels at the same depth of Bs light are not due to the difference in the absorption intensity of hemoglobin but are properties of V light and Bs light, respectively.

  The illumination light generated by the light source unit 20 and the band limiting filter 25 for Bs light generation is incident on the light guide 41 passed through the insertion unit 12 a via the optical path coupling unit 24 (see FIG. 2). The light guide 41 is incorporated in the endoscope 12 and the universal cord (a cord for connecting the endoscope 12 with the endoscope light source device 14 and the processor device 16), and is guided from the optical path coupling unit 24 The illumination light is propagated to the distal end 12 d of the endoscope 12. As the light guide 41, a multimode fiber can be used. As an example, it is possible to use a small diameter fiber cable having a core diameter of 105 μm, a cladding diameter of 125 μm, and a protective layer serving as an outer shell and a diameter of 0.3 to 0.5 mm.

  An illumination optical system 30 a and an imaging optical system 30 b are provided at the distal end 12 d of the endoscope 12. The illumination optical system 30 a has an illumination lens 45, and the illumination light propagated by the light guide 41 is irradiated to the observation target via the illumination lens 45. The imaging optical system 30 b includes an objective lens 46, a zoom lens 47, and an imaging sensor 48. The return light from the observation target (the reflected light and the light including the fluorescence generated from the observation target etc.) is incident on the imaging sensor 48 through the objective lens 46 and the zoom lens 47. As a result, the observation target is imaged on the imaging sensor 48. The zoom lens 47 is freely moved between the tele end and the wide end by operating the zoom operation unit 13, and enlarges or reduces the observation target formed on the imaging sensor 48.

  The imaging sensor 48 is a color imaging sensor, which images return light from the observation target and outputs an image signal. As the imaging sensor 48, a CCD (Charge Coupled Device) imaging sensor or a CMOS (Complementary Metal-Oxide Semiconductor) imaging sensor can be used. Further, as shown in FIG. 15, the imaging sensor 48 is provided with color filters of three colors of R (red) color filter, G (green) color filter, and B (blue) color filter for each pixel. The return light from the observation target is imaged to output an image signal for each color. That is, the imaging sensor 48 includes an R pixel (red pixel) provided with an R color filter, a G pixel (green pixel) provided with a G color filter, and a B pixel (blue pixel) provided with a B color filter. And outputs an image signal from each pixel to output an RGB image signal. Specifically, the imaging sensor 48 receives each return light of V light and Bs light in the illumination light by the B pixel, and outputs a blue image signal (hereinafter referred to as a B image signal). Similarly, among the illumination light, return light of G light is received by G pixel, a green image signal (hereinafter referred to as G image signal) is output, return light of R light is received by R pixel, red image signal ( Hereinafter, the R image signal is output.

  The light amount ratio setting unit 23 sets the light amount ratio of V light having depth resolution to blood vessels under the observation target mucous membrane and Bs light having thickness resolution to blood vessels of the same depth under the mucous membrane. Since the setting is made, in the B image signal among the image signals of each color, the contrast of the blood vessel with respect to the mucous membrane is the target contrast according to the depth and the thickness of the blood vessel.

  A complementary color imaging sensor provided with complementary color filters of C (cyan), M (magenta), Y (yellow) and G (green) may be used instead of the imaging sensor 48 which is a color imaging sensor of primary colors. When a complementary color imaging sensor is used, four color CMYG image signals are output. Therefore, the four color CMYG image signals are converted to three color RGB image signals by complementary color-primary color conversion. An RGB image signal similar to that of the imaging sensor 48 can be obtained. Also, instead of the imaging sensor 48, a monochrome sensor provided with no color filter may be used. In this case, by providing, for example, a rotary band limiting filter (color filter) in the light source unit 20, the light source control unit 22 performs time division of V light, B light, G light, and R light as necessary. Turn on. However, since both the V light and the B light are received by the B pixel, the V light and the B light may be lighted simultaneously.

  The image signal output from the imaging sensor 48 is transmitted to the CDS / AGC circuit 50. The CDS / AGC circuit 50 performs correlated double sampling (CDS) and automatic gain control (AGC) on an image signal which is an analog signal. The image signal passed through the CDS / AGC circuit 50 is converted by the A / D converter 51 into a digital image signal. The digital image signal after A / D conversion is input to the processor unit 16.

  The processor unit 16 includes a receiving unit 53, a DSP (Digital Signal Processor) 56, a noise removing unit 58, an image generating unit 62, and a video signal generating unit 66.

  The receiving unit 53 receives digital RGB image signals from the endoscope 12. The DSP 56 performs various signal processing such as defect correction processing, offset processing, gain correction processing, linear matrix processing, gamma conversion processing, and demosaicing processing on the received image signal. In the defect correction process, the signal of the defective pixel of the imaging sensor 48 is corrected. In the offset process, the dark current component is removed from the RGB image signal subjected to the defect correction process, and an accurate zero level is set. In the gain correction process, the signal level is adjusted by multiplying the RGB image signal after the offset process by a specific gain. The RGB image signal after the gain correction processing is subjected to linear matrix processing to improve color reproducibility. After that, brightness and saturation are adjusted by gamma conversion processing. The RGB image signal after linear matrix processing is subjected to demosaicing processing (also referred to as isotropic processing and synchronization processing), and a signal of a color lacking in each pixel is generated by interpolation. By this demosaicing process, all pixels have signals of RGB colors.

  The noise removing unit 58 removes noise from the RGB image signal by performing a noise removing process (for example, using a moving average method or a median filter method) on the RGB image signal subjected to the demosaicing process or the like by the DSP 56. The RGB image signal from which the noise has been removed is transmitted to the image generation unit 62.

  The image generation unit 62 performs color conversion processing, color enhancement processing, and structure enhancement processing on the RGB image signal to generate an image (hereinafter referred to as an endoscopic image). In color conversion processing, color conversion processing is performed on an RGB image signal by 3 × 3 matrix processing, tone conversion processing, three-dimensional LUT (look-up table) processing, or the like. The color emphasizing process is performed on the color-converted RGB image signal. The structure emphasizing process is, for example, a process of emphasizing the structure of an observation target such as a superficial blood vessel or a pit pattern, and is performed on the RGB image signal after the color emphasizing process. As described above, a color image using an RGB image signal subjected to various image processing and the like up to the structure enhancement processing is an endoscope image. The video signal generation unit 66 converts the endoscopic image generated by the image generation unit 62 into a video signal that can be displayed on the monitor 18. The monitor 18 displays an endoscopic image by using this video signal.

  Next, the operation of the endoscope system 10 will be described. In the endoscope system 10, the light amount ratio setting unit 23 sets the light amount ratio of the V light and the Bs light so that the contrast of the blood vessel with respect to the mucous membrane becomes the target contrast according to the depth and thickness of the blood vessel. For example, as shown in Table 1, the light amount ratio A0 to A10 of V light and Bs light is preset in the light amount ratio setting unit 23, and from these, the doctor selects depth and thickness of the B image signal. The balance of contrast between different blood vessels is selected and set to the light amount ratio that achieves the balance of the target contrast. The values of the light amount ratios A1 to A9 in Table 1 are the light amount of the peak wavelength of V light / the light amount of the peak wavelength of Bs light. The light amount ratio A0 is a setting in which the component of the wavelength band to be received by the B pixel is only Bs light by turning off the V-LED of the first light source 20a and turning on the B-LED of the second light source 20b. The light amount ratio A10 is a setting in which the component of the wavelength band received by the B pixel is only V light by turning on the V-LED of the first light source 20a and turning off the B-LED of the second light source 20b.

  FIG. 16 shows the contrast of the blood vessel with respect to the mucous membrane when the light amount ratio of V light to Bs light is set to each light amount ratio of A0 to A10. In FIG. 16, bar graphs representing contrasts of blood vessels having different depths and thicknesses obtained by setting the light amount ratio are arranged in order of d5φ20, d5φ40, d15φ20, d15φ40, d50φ20, and d50φ40 from the left. As can be seen from FIG. 16, as the component of V light increases, the difference in contrast between blood vessels having different thicknesses decreases, and the blood vessel contrast with respect to the mucous membrane is enhanced according to the submucosal depth. On the contrary, as the component of Bs light increases, the contrast becomes different according to the thickness of the blood vessel as well as the depth of the submucosa.

  The doctor determines the target contrast according to the characteristics of the lesion to be differentiated or according to the purpose such as eliminating the difference in the feeling of use from the conventional endoscope system, and the light quantity ratio A0 to A10 at which the defined target contrast is obtained. And select the desired light intensity ratio. The light source control unit 22 controls the first light source 20 a and the second light source 20 b such that the light amount ratio of the V light and the Bs light becomes the light amount ratio set by the light amount ratio setting unit 23. Therefore, in the B image signal obtained by the B pixel that receives the return light of the V light and the Bs light, the balance of the contrast of the plurality of blood vessels having different depths and thicknesses corresponds to the balance corresponding to the set light amount ratio. Become. The endoscopic image is generated using the B image signal in the image generation unit 62. Therefore, in the endoscopic image generated and displayed by the endoscope system 10, the contrast of the blood vessel with respect to the mucous membrane is the depth of the blood vessel and the It becomes the target contrast according to the thickness.

  In the first embodiment, although 11 types of light amount ratios A0 to A10 are illustrated, in the endoscope system 10, since the light amount ratio of V light and Bs light can be arbitrarily set, the endoscope system 10 can be used. 10 can freely adjust the contrast of the blood vessel according to the submucosal depth and thickness.

Second Embodiment
An endoscope system 200 of the second embodiment shown in FIG. 17 is an endoscope system capable of performing so-called narrow band light observation performed in a conventional endoscope system. In the endoscope system 200, blue narrow band light having the blue wavelength band of about 450 nm or less from white light emitted from the second light source 20b in the light path of the second light source 20b (same as Bs light of the first embodiment So, hereinafter, Bs light and the wavelength band of Bs light (third wavelength band) are different, and a green wavelength band of about 530 nm to 550 nm (fourth wavelength band) having thickness resolution for blood vessels A band narrowing filter 225 for generating Bs light and Gn light that generates green narrow band light (hereinafter, Gn light) having the above is provided so as to be insertable and removable. The green wavelength band of Gn light is the fourth wavelength band, which is different from the wavelength band of Bs light (third wavelength band), and has a thickness resolution for blood vessels (see FIG. 6). The band limiting filter 225 for Bs light and Gn light generation is a first band limiting filter and a second band limiting filter.

  The mode switching unit 230 controls the insertion and removal of the band limiting filter 225 for Bs light and Gn light generation. The observation mode switching unit 230 is operated by the operation of an observation mode switching button (not shown) in the operation unit 12 b, a foot switch (not shown), etc., and white light by inserting and removing the band limiting filter 225 for generating Bs light and Gn light. And the second observation mode in which observation is performed using V light, Bs light, and Gn light. The first observation mode is a so-called normal observation mode, and the second observation mode is a so-called narrow band observation mode. Therefore, when the second observation mode for narrow band light observation is selected, the observation mode switching unit 230 selects the band limiting filter 225 for generating the Bs light and the Gn light as the second light source 20b. When the first observation mode is selected which is inserted into the optical path and irradiated with white light for normal observation, the band limiting filter 225 for generating Bs light and Gn light is retracted from the optical path of the second light source 20b. .

  As shown in FIG. 18, the illumination light 226 when narrowband light observation is performed by the endoscope system 200 is configured by V light, Bs light, and Gn light. Then, in the image generation unit 62 of the endoscope system 200, a B image signal obtained by imaging the return light of the V light and the Bs light with the B pixel is used as the B channel (B pixel of the endoscope image to be generated) Allocated to the G channel (G pixel of the endoscope image to be generated) and G image signal obtained by imaging the return light of Gn light by the G pixel was allocated to the R channel (R pixel of the endoscope to be generated) An endoscopic image (hereinafter referred to as a narrow band light observation image) is generated. Other than this, it is the same as the endoscope system 10 of the first embodiment.

  As shown in FIG. 19, in a conventional endoscope system, a band limiting filter (hereinafter referred to as a band limiting filter for wide band light) limits the wavelength band of wide band light from wide band light having a wider wavelength band than V light or Bs light. Narrow band light observation using narrow band light generated by For example, when a xenon lamp is used as a light source, the broadband light is white light 227 emitted from the xenon lamp, and from this white light 227, a blue light having a wavelength band of about 350 nm to 450 nm Narrow-band light (hereinafter referred to as Bn light) and Gn light are generated, and these are used as illumination light to image an observation target. When narrow-band light observation is performed, the Gn light of the endoscope system 200 can have almost the same spectral spectrum as the Gn light of the conventional endoscope system, so the depth and thickness of the G image signal are different. The balance of contrast of multiple blood vessels is approximately equal to that of conventional endoscopic systems. On the other hand, as shown in FIG. 20, the spectral spectra of Bn light used in the conventional endoscope system and V light and Bs light used in the endoscope system 200 do not match. Therefore, the depth and the B image signal obtained when narrow band light observation is performed by the conventional endoscope system and the B image signal obtained when narrow band light observation is performed by the endoscope system 200 are: The balance of contrast for the mucous membranes of blood vessels of different thickness is not the same.

  However, in the endoscope system 200, by setting the light amount ratio of V light and Bs light by the light amount ratio setting unit 23, it is possible to balance the contrast among a plurality of blood vessels having different depths and thicknesses in the B image signal. Can be adjusted. That is, in the endoscope system 200, the contrast of the blood vessel in the case of irradiating the observation target with the Bn light generated from the wide band light using the wide band light band-limiting filter as the target contrast, the light amounts of the V light and the Bs light By setting the ratio, the balance of contrast of blood vessels of different depth and thickness in the B image signal is made to match the balance of contrast in the B image signal of the endoscope system that performs conventional narrow-band light observation. be able to. As a result, it is possible to substantially match the appearance of blood vessels in the narrowband light observation image generated and displayed by the endoscope system 200 with the appearance of blood vessels in the conventional narrowband light observation image.

  First, as shown in FIG. 21, the balance of the blood vessel contrast of the B image signal obtained when the conventional Bn light generated from the wide band light is irradiated is Bs light only (the light amount ratio A0 in the endoscope system 200). And the balance of the contrast of the B image signal in the case where only V light (light amount ratio A10) is irradiated.

  On the other hand, in FIG. 22, the contrast of the blood vessel with respect to the mucous membrane when the light amount ratio setting unit 23 sets the light amount ratio of V light and Bs light to the light amount ratio A0 to A10 (see Table 1) of the first embodiment The contrast ratio obtained by normalizing the contrast of the blood vessel to the mucous membrane when irradiated with Bn light of Further, FIG. 22 shows contrast ratios of a plurality of blood vessels having different depths and thicknesses. For this reason, the graph in FIG. 22 indicates that the closer the value is to 100%, the closer the contrast of the blood vessel to the mucous membrane is to that in the case of conventional Bn light irradiation.

  As can be seen from FIG. 22, when the light amount ratio A0 to A6 is set, the variation depending on the depth and depth of the blood vessels becomes large, but the contrast (100%) when many blood vessels are irradiated with the conventional Bn light Line), and the visibility improves more than before. On the other hand, when the light amount ratio A7 to A10 is set, the contrast in the case of irradiating the conventional Bn light is slightly lower, but the variation in contrast due to the depth and thickness of the blood vessel becomes smaller, and the case of irradiating the conventional Bn light A close contrast balance is obtained.

  In addition, in FIG. 23, when the light quantity ratio setting unit 23 sets the light quantity ratios A0 to A10 (see Table 1) of V light and Bs light, blood vessels having equal submucosal depths and different thicknesses. And a graph of the contrast ratio between them. Specifically, in FIG. 23, the contrast ratio (φ40 / φ20) of the φ40 blood vessel to the φ20 blood vessel is shown at three depths d5, d15, and d50. Further, since the graph in FIG. 23 is normalized by the contrast ratio in the case of conventional Bn light irradiation, as the value is closer to 100%, the submucosal depth is equal, and between blood vessels different in thickness. Represents a contrast ratio close to that in the case of irradiating conventional Bn light.

  As can be seen from FIG. 23, when the light amount ratio A0 to A6 is set, the contrast ratio between blood vessels having the same depth and different thickness under the mucous membrane has a large variation due to the difference in depth, but the value is It exceeds 100% and is generally larger than the case of irradiating conventional Bn light. For this reason, when the light amount ratio A0 to A6 is set, blood vessels having the same depth and different thickness can be observed more clearly and specifically than in the case where conventional Bn light is irradiated. On the other hand, when the light amount ratio is set to A7 to A10, the contrast ratio between blood vessels having the same depth in the submucosa and different in thickness may be slightly lower than in the case where conventional Bn light is irradiated. The variation due to the difference in B.sub.2 is small, and a value close to the contrast ratio in the case of conventional Bn light irradiation can be maintained. In particular, when the light amount ratio is set to A7 to A9, the contrast ratio between blood vessels having the same depth and different thickness under the mucous membrane has almost no variation due to the difference in depth, and the conventional Bn light It almost matches the contrast ratio in the case of irradiation.

  In FIG. 24, when the light amount ratio setting unit 23 sets the light amount ratios A0 to A10 (see Table 1) of V light and Bs light, between blood vessels having the same thickness and different submucosal depths. 7 shows a graph of contrast ratio. Specifically, in FIG. 24, with respect to blood vessels of two types of φ20 and φ40, the contrast ratio (d5 / d15) of the blood vessel of depth d5 to the blood vessel of depth d15 and the depth to the blood vessel of depth d50 It shows the contrast ratio (d15 / d50) of the blood vessel of d15. In addition, since the graph in FIG. 24 is normalized by the contrast ratio in the case of conventional Bn light irradiation, as the value is closer to 100%, the blood vessels are equal in thickness and between blood vessels having different submucosal depths. Represents a contrast ratio close to that in the case of irradiating conventional Bn light.

  As can be seen from FIG. 24, the contrast ratio between blood vessels of equal thickness and different submucosal depths does not depend on the setting of the light quantity ratio, and a value close to that obtained when irradiating conventional Bn light is obtained. Be However, the contrast ratio of a relatively thin blood vessel (φ 20) tends to decrease with the light amount ratio A0 to A6 having many components of Bs light at the boundary of the light amount ratio A7, and the variation due to the difference in blood vessel diameter increases. Also, if the light amount ratio A8 to A10 with many V light components is set at the boundary of the light amount ratio A7, the contrast ratio due to the difference in the blood vessel depth of almost all the thickness will vary due to the difference in the thickness While being small, it exceeds the contrast ratio in the case of irradiating conventional Bn light. Therefore, when the light amount ratio is set to A8 to A10, it becomes easier to identify blood vessels having the same thickness and different submucosal depths than in the case of irradiating conventional Bn light.

  Table 2 also shows (1) contrast balance between blood vessels of different depths and thicknesses, (2) contrast ratio between blood vessels of equal submucosal depth and different thickness, (3) B image signal obtained when the light amount ratio is set to A0 to A10 in the endoscope system 200 from the three viewpoints of contrast ratios between blood vessels having equal thicknesses and different submucosal depths The result of having evaluated five steps of 1-5 functionally with B image signal obtained by irradiating conventional Bn light is shown. The evaluation is “1”, which indicates that the conventional Bn light irradiation is the most distant, and “5”, which is the closest evaluation to the conventional Bn light irradiation. An evaluation result is an average value of the result which two or more persons evaluated.

From the above, the blue narrow band light used in the endoscope system 200 is formed of V light and Bs light, which is different from the Bn light formed from the conventional wide band light, and the spectral spectra do not match, If the light quantity ratio setting unit 23 sets the light quantity ratio of V light and Bs light to the value of “A7” (light quantity of peak wavelength of V light / light quantity of peak wavelength of Bs light = 5.0), blood vessel contrast Size of the blood vessel is approximately equal to that of the blood vessel when the Bn light is irradiated to the observation target,
It is possible to obtain a B image signal in which the balance of contrast with respect to the mucous membranes of a plurality of blood vessels different in depth and thickness is substantially the same as in the case where conventional Bn light is irradiated. Therefore, the endoscope system 200 can generate and display a conventional narrowband light observation image and a narrowband light observation image having almost the same appearance as a blood vessel.

  As described above, the light amount ratio setting unit 23 sets the light amount ratio of V light to Bs light to the value of “A7” in order to obtain the narrow band light observation image in which the way of seeing a blood vessel is substantially the same as the conventional narrow band light observation image. It is most preferable to set to the following value, but if the value of “the light amount of peak wavelength of V light / the light amount of peak wavelength of Bs light” is 2.0 (light amount ratio A6) or more and 8.0 (light amount ratio A8) or less In addition, it is possible to obtain a narrow band light observation image in which a conventional narrow band light observation image and a blood vessel look substantially the same. In addition, if the value of “the light amount of the peak wavelength of V light / the light amount of the peak wavelength of Bs light” is about 1.0 (light amount ratio A4) or more, the narrow band mimics the conventional narrow band light observation image without discomfort A light observation image can be generated and displayed.

  Besides, in the endoscope system 200, the light amount ratio setting unit 23 sets the light amount ratio of V light and Bs light to “A0” to “A6”, so that the depths under the mucous membrane are equal and the thickness is equal. A blood vessel when the observation target is irradiated with Bn light generated from a wide band light having a wider wavelength band than V light or Bs light from a wide band light with a wide band band filter for wide band light than a contrast ratio or difference of multiple blood vessels having different The ratio or difference of the contrasts of That is, by setting the light amount ratio to “A0” to “A6”, when using the conventional Bn light, the contrast ratio or difference of a plurality of blood vessels having the same depth in the submucosa and different in thickness It is possible to provide a new narrowband light observation image that is more emphasized.

  Further, in the endoscope system 200, by setting the light amount ratio of the V light and the Bs light to “A8” to “A10” by the light amount ratio setting unit 23, the depth under the mucous membrane is different and the thickness is The contrast ratio or difference between equal multiple blood vessels can be made larger based on the blood vessel contrast ratio or difference when irradiating the Bn light to the observation target. That is, by setting the light amount ratio to “A8” to “A10”, when using the conventional Bn light, the contrast ratio or difference of a plurality of blood vessels having different submucosal depths and equal thicknesses is used. It is possible to provide a new narrowband light observation image that is more emphasized.

  In the second embodiment, Bn light and Gn light are generated and used from white light 227 emitted from a xenon lamp as an endoscope system 200 and a conventional endoscope system for narrow band light observation. Although an endoscope system is compared, there is also an endoscope system which performs narrow band light observation using a light source (for example, white LED etc.) which emits wide band light other than a xenon lamp. In the endoscope system 200, as in the second embodiment, if an appropriate light amount ratio is set by the light amount ratio setting unit 23, the narrowband light observation image and the appearance of blood vessels obtained by such a conventional endoscope system are obtained. A narrow band light observation image can be obtained which is almost equal.

  In the second embodiment, Bs light and Gn light are simultaneously generated from white light emitted by the second light source 20b using the band limiting filter 225 for generating Bs light and Gn light, but instead, for example, as shown in FIG. The light source control unit 22 sequentially generates Bs light and Gn light using the rotary type band-limiting filter (hereinafter referred to as a rotary filter) 235 shown in FIG. It is good. The rotation filter 235 is a band limiting filter for Bs light generation (first band limiting filter for generating Bs light from white light emitted from the second light source 20b (first band limiting filter. Corresponds to the band limiting filter 25 for Bs light generation of the first embodiment). And a band limiting filter for generating Gn light (second band limiting filter) for generating Gn light at the outer peripheral portion, and the white light emitted from the second light source 20b is transmitted to the inner periphery. It has a through portion 235c. When the second observation mode in which narrow band light observation is performed is selected, the observation mode switching unit 230 causes the Bs light generation band-limiting filter 235a and the Gn light generation band-limiting filter 235b to alternate between the second light source 20b. A rotary filter 235 is disposed and rotated across the light path. On the other hand, when the first observation mode in which normal observation is performed is selected, the observation mode switching unit 230 arranges the blank part 235c in the optical path of the second light source 20b. When a monochrome sensor is used as the imaging sensor 48, it is preferable to sequentially generate Bs light and Gn light and perform time division irradiation as described above using the rotation filter 235 or the like.

  Note that, instead of the V-LEDs and B-LEDs used in the first embodiment and the second embodiment, other semiconductor light sources having different center wavelengths, peak wavelengths, etc., can also be used. For example, in the first and second embodiments, a V-LED emitting V light with a central wavelength of 415 nm is used, but instead, an LED emitting V light with a central wavelength of 405 nm may be used instead, for example. . Even when an LED with a central wavelength of 405 nm is used, the light amount ratio set by the light amount ratio setting unit 23 is substantially the same as the light amount ratio in the first and second embodiments. Moreover, you may use other semiconductor light sources, such as a laser diode, instead of LED.

  In the first embodiment and the second embodiment, the light source control unit 22 uses the light amount ratio set by the light amount ratio setting unit 23 to use the V-LED of the first light source 20a and the B-LED of the second light source 20b. The light amount (light emission amount) is controlled, but instead of controlling the light amount, the light emission ratio of the V light to the Bs light is controlled by controlling the light emission time of the V-LED and B-LED. It may be a ratio. Alternatively, the light amount ratio of the V light and the Bs light may be set to the light amount ratio set by the light amount ratio setting unit 23 by controlling both the light amount and the light emission time. There is a limit to the light quantity of V-LED and B-LED, but if the light emission time is controlled, or if both the light quantity and the light emission time are controlled, the V light and Bs can not be realized by the light quantity ratio alone. Illumination light including light can be generated.

  In the first and second embodiments, Bs light is generated from B light and used as illumination light, but B light may be used as it is as illumination light. However, as described above, it is easier to obtain the blood vessel contrast to the mucous membrane when Bs light is used.

  In the first and second embodiments described above, the present invention is implemented by the endoscope system that inserts the endoscope 12 provided with the imaging sensor 48 into the subject and performs observation. The invention is also suitable for an endoscope system. For example, as shown in FIG. 26, the capsule endoscope system at least includes a capsule endoscope 400 and a processor (not shown).

  The capsule endoscope 400 includes a light source 402, a control unit 403, an imaging sensor 404, an image generation unit 406, and a transmitting and receiving antenna 408. The light source 402 includes a V-LED that emits V light, a B-LED that emits B light, a phosphor that emits fluorescence by irradiation of B light, and a band limiting filter for Bs light generation. It corresponds to the light source unit 20 of the first embodiment and the second embodiment.

  The control unit 403 functions in the same manner as the light source control unit 22 and the light amount ratio setting unit 23 in the first and second embodiments, and controls the light emission of the light source 402 by setting the light amount ratio of V light and Bs light. . Further, the control unit 403 can wirelessly communicate with the processor device of the capsule endoscope system by the transmission / reception antenna 408. The processor device of the capsule endoscope system is substantially the same as the processor device 16 of each of the above-described embodiments and the modification, but the image generation unit 406 is provided in the capsule endoscope 400, and the generated endoscopic image is , And transmitted to the processor unit via the transmitting / receiving antenna 408. The imaging sensor 404 is configured in the same manner as the imaging sensor 48 of the first embodiment and the second embodiment.

10, 200 Endoscope System 12 Endoscope 14 Endoscope Light Source Device 16 Processor Unit 20a First Light Source 20b Second Light Source 22 Light Source Control Unit 23 Light Intensity Ratio Setting Unit 25, 235a Bs Band Generation Filter for Bs Light 225 Bs Light And Gn light generation band limiting filter 230 observation mode switching unit 235 b Gn light generation band limiting filter

Claims (15)

A first light source that emits V light, which is violet light having depth resolution, for a blood vessel under the mucosa to be observed;
A second light source that emits fluorescence obtained by irradiating the phosphor with blue light B light and the B light as excitation light;
Of the light emitted from the second light source, Bs light and Gn light for transmitting at least Bs light, which is blue narrow band light, and Gn light, which is green narrow band light having thickness resolution for blood vessels A band limiting filter,
A light amount ratio setting unit for setting a light amount ratio of the V light and the Bs light and setting a contrast of a blood vessel to a mucous membrane to a target contrast according to a depth and a thickness of the blood vessel;
A light source control unit configured to control the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit;
Endoscope light source device provided with.   The peak wavelength of the V light is shorter than the peak of the absorption spectrum of hemoglobin, and the peak wavelength of the Bs light is longer than the peak of the absorption spectrum of hemoglobin. Endoscope light source device.   The endoscope light source device according to claim 1, wherein the light amount ratio setting unit sets the light amount ratio by setting the contrast of the blood vessel when the Bs light is irradiated to the observation target as the target contrast.   The light amount ratio setting unit sets the light amount ratio to equalize the balance of contrast of a plurality of blood vessels having the same depth in the submucosa and different in thickness with the balance in the case of irradiating the Bs light to the observation target. The endoscope light source device according to claim 3 to set up.   The light amount ratio setting unit sets the light amount ratio to equalize the balance of contrast of a plurality of blood vessels having different submucosal depths and equal thicknesses with the balance when irradiating the Bs light to the observation target. The endoscope light source device according to claim 3 or 4 to set up.   The light quantity ratio setting unit sets the light quantity ratio to make the size of the contrast of the blood vessel equal to the size of the contrast of the blood vessel when the Bs light is irradiated to the observation target. The endoscopic light source device as described in a term. Based on the contrast of the blood vessel when the Bs light is irradiated to the observation target,
The light amount ratio setting unit makes the ratio or the difference of the contrast of a plurality of blood vessels having the same depth in the submucosa and the different thickness larger than the ratio or the difference of the contrast in the case of irradiating the Bs light. The endoscope light source device according to claim 1, wherein the light amount ratio is set. Based on the contrast of the blood vessel when the Bs light is irradiated to the observation target,
The light amount ratio setting unit makes the ratio or difference of contrast of a plurality of blood vessels having different submucosal depths and equal thicknesses larger than the ratio or difference of the contrast when the Bs light is irradiated. The endoscope light source device according to claim 1, wherein the light amount ratio is set.   The light source control unit according to any one of claims 1 to 8, wherein the light emission amount of the first light source and the second light source is controlled using the light amount ratio set by the light amount ratio setting unit. Endoscope light source device.   The light amount ratio setting unit controls the light emission time of the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit. Endoscope light source device.   9. The light source control unit according to claim 1, wherein both of the light emission amount and the light emission time of the first light source and the second light source are controlled using the light amount ratio set by the light amount ratio setting unit. The endoscopic light source device as described in a term.   The first light source is a V-LED that emits the V light, and the second light source includes a B-LED that emits the B light, and the phosphor. Endoscope light source device.   The endoscope light source device according to any one of claims 1 to 12, wherein the fluorescence includes G light which is green light and R light which is red light. A first light source that emits V light, which is violet light having depth resolution, for a blood vessel under the mucosa to be observed;
A second light source that emits fluorescence obtained by irradiating the phosphor with blue light B light and the B light as excitation light;
Of the light emitted from the second light source, Bs light and Gn light for transmitting at least Bs light, which is blue narrow band light, and Gn light, which is green narrow band light having thickness resolution for blood vessels A band limiting filter,
A light amount ratio setting unit for setting a light amount ratio of the V light and the Bs light and setting a contrast of a blood vessel to a mucous membrane to a target contrast according to a depth and a thickness of the blood vessel;
A light source control unit configured to control the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit;
An imaging sensor for imaging the observation target;
An endoscope system comprising: A first light source for emitting V light, which is purple light having depth resolution, and B light, which is blue light, and B light which is excitation light, for a blood vessel under a mucous membrane to be observed Among the light emitted from the second light source, the second light source emitting fluorescence obtained by the irradiation, Bs light which is blue narrow band light, and Gn which is green narrow band light having thickness resolution with respect to the blood vessel In a method of operating an endoscope light source apparatus, the method comprises: a band limiting filter for generating Bs light and Gn light that transmits at least light.
A light amount ratio setting unit sets a light amount ratio of the V light and the Bs light;
Controlling the first light source and the second light source using the light amount ratio set by the light amount ratio setting unit;
Method of operating an endoscopic light source device comprising:

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