Light source device, endoscope system, and control method

Abstract

An endoscope device (10) includes a light source section (140) and a processing circuit (120). A ratio of a spectral reflectance of a mark of each wavelength region to a spectral reflectance of a surrounding portion is set as a mark observation ratio, where each wavelength region is each of a plurality of wavelength regions into which a visible light wavelength region is divided. The processing circuit (120) sets a spectral shape of illumination light based on spectral setting information of the mark observation ratio, thereby relatively emphasizing the mark compared to the surrounding portion. Alternatively, the processing circuit (120) performs image processing that emphasizes the mark according to the spectral setting information in a captured image, thereby relatively emphasizing the mark compared to the surrounding portion.

Description

Technical Field

[0001] This invention relates to light source devices, endoscope systems, and control methods. Background Technology

[0002] In endoscopic observation, it is known that methods using markers (merkmals) as indicators are used to determine the presence or likelihood of a site of interest. Patent Document 1 discloses a method where fat is considered as a nerve marker. The method utilizes a wavelength region B1 with high absorbance of β-carotene contained in fat, and sequentially illuminates the object using light from wavelengths B1, G1, and R1 to generate a white observation image.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 13 / 115323 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In current imaging techniques for endoscopic devices, the focus is on utilizing the spectroscopic characteristics of areas of interest to improve visual recognition. However, in such imaging techniques, when the difference in spectroscopic characteristics between areas of interest, such as nerves, and peripheral areas, such as mucous membranes, is small, it is difficult to emphasize the area of ​​interest relative to the peripheral areas using spectroscopic methods such as adjusting the illumination spectrum. Thus, there is a challenge in improving the visual recognition of areas of interest that lack spectroscopic characteristics. Patent Document 1 uses fat as a marker for nerves, utilizing the wavelength region B1, which contains β-carotene and has high absorbance. However, it does not disclose the following: the lack of spectroscopic characteristics of areas of interest, such as nerves, relative to peripheral areas such as mucous membranes; and the use of markers to emphasize areas of interest by considering the ratio of spectroscopic reflectance between the marker and the peripheral areas.

[0008] Methods for solving problems

[0009] One aspect of the present invention relates to an endoscope device comprising: a light source unit that generates illumination light to illuminate an object being observed; and a processing circuit that controls the illumination light in the light source unit, wherein the object being observed comprises, within the field of view of an image obtained by photographing the object being observed,: a marker, which is a component existing in a region other than a region of interest and existing in a region related to the region where the region of interest exists; and a peripheral region, which is a region other than the region of interest and does not contain the marker, wherein the marker observation ratio is defined as the ratio of the spectral reflectance of the marker in each wavelength region to the spectral reflectance of the peripheral region, wherein each wavelength region is a wavelength region among a plurality of wavelength regions divided by a visible light wavelength region, and the processing circuit controls the spectral shape of the illumination light according to spectral setting information based on the marker observation ratio, thereby relatively emphasizing the marker compared to the peripheral region.

[0010] Another aspect of the present invention relates to an endoscope device comprising: an image acquisition unit that acquires an image obtained by photographing an object being observed; and a processing circuit that performs image processing on the acquired image, wherein the object being observed comprises, within the field of view of the image obtained by photographing the object being observed,: a marker, which is a component existing in a region other than a region of interest and existing in a region related to the region where the region of interest exists; and a peripheral region, which is a region other than the region of interest and does not contain the marker, wherein the marker observation ratio is defined as the ratio of the spectral reflectance of the marker in each wavelength region to the spectral reflectance of the peripheral region, wherein each wavelength region is a wavelength region among a plurality of wavelength regions divided by a visible light wavelength region, and the processing circuit performs image processing to emphasize the marker in the image obtained by photographing the object being observed based on spectral setting information based on the marker observation ratio, thereby relatively emphasizing the marker compared to the peripheral region.

[0011] Another aspect of the present invention relates to an observation method for observing an object based on reflected light from an object illuminated by illumination light. The object includes: a marker contained within the field of view of an image obtained by photographing the object, which is a component existing in a region outside the region of interest and in a region related to the region where the region of interest exists; and a peripheral region within the field of view, which is a region outside the region of interest and does not contain the marker. The marker observation ratio is defined as the ratio of the spectral reflectance of the marker in each wavelength region to the spectral reflectance of the peripheral region, wherein each wavelength region is one of multiple wavelength regions divided by a visible light wavelength region. The spectral shape of the illumination light is controlled according to spectral setting information based on the marker observation ratio to generate illumination light having the controlled spectral shape, thereby relatively emphasizing the marker compared to the peripheral region. Alternatively, in an image obtained by photographing the object, image processing is performed to emphasize the marker according to the spectral setting information, thereby relatively emphasizing the marker compared to the peripheral region. Attached Figure Description

[0012] Figure 1 This is a structural example of an endoscope device.

[0013] Figure 2 These are examples of images of the object being observed captured by an endoscopic device.

[0014] Figure 3 It is the spectral reflectance of the stomach, large intestine, and esophagus.

[0015] Figure 4 It is the spectral reflectance of the large intestine, fat, nerves, and β-carotene.

[0016] Figure 5 This is a detailed structural example of the light source and processing circuit.

[0017] Figure 6 This is an example of the spectrum of the illumination light generated by the light source.

[0018] Figure 7 This is the first example of the light intensity ratio in the first embodiment.

[0019] Figure 8 This is the second example of the light intensity ratio in the first embodiment.

[0020] Figure 9 This is the third example of the light intensity ratio in the first embodiment.

[0021] Figure 10 This is a diagram illustrating the image processing in a first variation of the first embodiment.

[0022] Figure 11 It is a table showing the effect of improving visual recognition.

[0023] Figure 12 It is the spectral reflectance of the esophagus and Lugol's.

[0024] Figure 13 This is the first example of the light intensity ratio in the second embodiment.

[0025] Figure 14 This is the second example of the light intensity ratio in the second embodiment.

[0026] Figure 15 This is a detailed structural example of the processing circuit in the third embodiment.

[0027] Figure 16 This is a diagram illustrating the image processing in the third embodiment. Detailed Implementation

[0028] The following describes this embodiment. Furthermore, the embodiments described below do not unduly limit the scope of the invention as defined in the claims. Also, not all structures described in this embodiment are necessarily essential components of the invention.

[0029] 1. Endoscopic device

[0030] Figure 1 This is a structural example of the endoscope device 10. Furthermore, the description of the structure and operation common to general endoscopes will be omitted below, and the description will focus on the features relevant to this invention. Additionally, the following description uses a medical endoscope for digestive organs as an example, but the application of this invention is not limited to this. That is, the term "endoscope" in this specification generally refers to a device having an insertion portion for observing the inner surface of a concave portion of various subjects. For example, an endoscope refers to a medical endoscope used for the examination or surgery of living organisms.

[0031] Figure 1 The endoscope device 10 includes a control device 100, an endoscope body 200, a display unit 300, and an input unit 600. The control device 100 is also referred to as an endoscope control device. The display unit 300 is also referred to as a display or display device. The input unit 600 is also referred to as an input device or operating device. First, the structure of the endoscope device 10 will be described.

[0032] The endoscope 200 comprises an insertion part 210, an operating part 220, a connecting cable 230, and a connector 240. The insertion part 210 can be inserted into the body cavity of a living organism. In flexible endoscopes such as those for digestive tracts, the insertion part 210 is flexible; in rigid endoscopes such as those for surgery, the shape of the insertion part 210 remains unchanged. The body cavity of the living organism is the object of observation in this embodiment. A doctor or other user holds the operating part 220 and uses it to operate the endoscope device 10. The connecting cable 230 is a cable that connects the control device 100 to the endoscope 200. The connector 240 is provided at one end of the connecting cable 230, allowing the control device 100 and the endoscope 200 to be attached and detached.

[0033] The insertion section 210 is provided with: illumination lenses 211 and 212 that emit illumination light toward the object being observed; and an imaging unit 213 that captures images by receiving illumination light reflected or scattered from the surface of the object being observed. The imaging unit 213 is also referred to as an imaging section or imaging device.

[0034] A light guide 214 is provided in the lens body 200. The light guide 214 is optically connected to the illumination lenses 211 and 212. A light source unit 140 is provided in the control device 100, and the light guide 214 guides the illumination light emitted from the light source unit 140 to the illumination lenses 211 and 212. The light guide 214 is an optical fiber bundle or the like. The light guide extends from the connector 240 through the connecting cable 230 and the operation unit 220 to the illumination lenses 211 and 212.

[0035] Illumination lenses 211 and 212 expand the illumination light guided by the light guide to the desired radiation angle. Illumination lenses 211 and 212 are illumination optical systems composed of one or more lenses.

[0036] The camera unit 213 includes a camera optical system and an image sensor. The image sensor may be, for example, a CMOS imager. The imager can be a Bayer-type imager equipped with RGB primary color filters arranged in a Bayer pattern, a complementary color imager equipped with complementary color filters, or a monochrome imager. A monochrome imager is used for mirror bodies with a surface-to-surface arrangement. In addition to a CMOS imager, a CCD may also be used as the image sensor.

[0037] An image signal line 215 is provided in the lens body 200 to transmit the image signal of the image captured by the camera unit 213 to the control device 100. The image signal line 215 is disposed in the insertion part 210, the operation part 220, and the connecting cable 230, and is connected to the control device 100 via the connector 240 in a manner that enables the transmission of image signals. In addition, the image signal line 215 may also be an optical fiber for optical communication.

[0038] The control device 100 includes a light source unit 140 that emits illumination light and a processing circuit 120. The processing circuit 120 includes: a control circuit 110 that controls each part of the endoscope device 10; an image processing circuit 112 that performs image processing on image signals from the camera unit 213; and a light source controller 150 that controls the light source unit 140.

[0039] The processing circuit 120 is implemented by a circuit arrangement in which multiple circuit components are mounted on a substrate. Alternatively, the processing circuit 120 may also be a processor or an integrated circuit device such as an ASIC (Application Specific Integrated Circuit). When the processing circuit 120 is a processor, the processor executes a program that describes the operation of the processing circuit 120, thereby implementing the operation of the processing circuit 120. The program is stored, for example, in a memory not shown. Furthermore, the control circuit 110, image processing circuit 112, and light source controller 150 included in the processing circuit 120 may be mounted on one substrate or multiple substrates. For example, the light source controller 150 may be mounted on a first substrate, and the control circuit 110 and image processing circuit 112 may be mounted on a second substrate. In this case, the light source unit 140 and the first substrate may also constitute a light source device.

[0040] The display unit 300 displays an image of the observed object after image processing by the image processing circuit 112. The display unit 300 is a commonly used display device, such as a liquid crystal monitor. The display unit 300 is electrically connected to the control device 100 via electrical wiring for transmitting image signals.

[0041] The input unit 600 accepts user input and outputs the input information to the processing circuit 120. The input unit 600 may be, for example, a button or dial, keyboard, mouse, touch panel, etc. The touch panel may also be located in the display unit 300. Alternatively, the input unit 600 may be an interface connected to an information processing device such as a PC (Personal Computer). The interface accepts input information from the information processing device and outputs the input information to the control circuit 110. The interface may be, for example, a communication interface such as USB (Universal Serial Bus) or LAN (Local Area Network).

[0042] The light source unit 140 has multiple light sources that emit multiple lights with different wavelengths. These multiple light sources may be, for example, three or more. The light source unit 140 directs these multiple lights as illumination light onto the mirror body 200. Each light source may be, for example, an LED (Light Emitting Diode), a semiconductor laser, or an SLD (Super Luminescent Diode). Alternatively, each light source may be a combination of a laser and a phosphor. By using an SLD, a light source with a narrower wavelength range and higher brightness than an LED can be achieved. Furthermore, by combining a phosphor and a laser, light of various wavelengths can be emitted with high brightness. By using a laser, high-brightness light can be efficiently guided to the light guide. Alternatively, a light source combining a lamp and a filter may be used. The filter is positioned along the optical path from the lamp to the incident end of the light guide. For example, a rotating filter has multiple filters with different transmission wavelengths, and the emitted light from each light source is achieved by rotating this rotating filter.

[0043] The light source controller 150 controls the emitted light amount of each light source included in the light source unit 140. Specifically, the light source controller 150 controls the spectral shape of the illumination light by controlling the emitted light amount ratio of the multiple light sources. The light source controller 150 may include, for example, a drive circuit for driving the light source; a drive control circuit or processor for controlling the drive circuit. Alternatively, if the light source includes a drive circuit, the light source controller 150 may also be a drive control circuit or processor for controlling the drive circuit of the light source.

[0044] Next, the operation of the endoscope device 10 in this embodiment will be described. In cases where the spectral characteristics of the area of ​​interest are lacking compared to surrounding areas, the endoscope device 10 in this embodiment alerts the user to the possibility of the area of ​​interest's presence by emphasizing a marker. Specifically, the endoscope device 10 improves the visual recognizability of the marker by controlling the spectral shape of the illumination light or by image processing to create an image as if illuminated by that illumination light.

[0045] First, use Figure 2 The parts of interest, markings, and surrounding areas included in the object of observation in this embodiment will be explained.

[0046] Figure 2 The IMG shown is an example of an image of the object of observation captured by the endoscope device 10. The object of observation includes the area of ​​interest (AINT), the marker (AMER), and the surrounding area (APPH). Figure 2This is an example where the areas of interest (AINT), markers (AMER), and surrounding areas (APPH) are present within the field of view of the image IMG. The field of view of the image IMG is determined by the optical system and imaging element of the imaging unit 213. Alternatively, the field of view of the image IMG can also be the field of view when the image IMG is displayed on the display unit 300.

[0047] A site of interest (AINT) is a region of interest within the observed object that the physician is focused on. Specifically, an AINT is a tissue that the physician wants to identify during examination, treatment, or surgery, a lesion that the physician wants to discover during screening, or a lesion that is the subject of examination or treatment. An AINT does not need to be captured in the exposed state in the image IMG; it can be partially or completely covered by other tissues if it is within the field of view. Figure 2 In the diagram, solid lines represent exposed areas of interest (AINT), and dashed lines represent areas of interest that are not exposed (AINT).

[0048] A marker mer is a component that exists outside the site of interest (AINT) and whose location is related to the location of the AINT. "Related location" means that it is likely to exist near the AINT, or that it exists exclusively in the vicinity of the AINT. Examples include components contained in tissues or organs highly likely to be present at the AINT, components contained in tissues or organs adjacent to the AINT, or drugs dispersed or injected intravenously during observation of the object. Here, regarding "likely to exist near the AINT," we will use nerves and fat as examples. If a nerve, which is the site of interest, is present, the likelihood of the marker fat being present is high. Conversely, if fat is considered, there may be cases where a nerve is actually present nearby, or cases where no nerve is present nearby. A marker fat only needs to be likely to exist near a nerve, which is the site of interest; therefore, a marker fat can include both fat where a nerve is actually present nearby and fat where no nerve is present nearby.

[0049] Peripheral area (APPH) refers to the area of ​​interest (AINT) within the observed object, excluding the area marked AMER. For example, in gastrointestinal endoscopy, the gastrointestinal mucosa corresponds to the peripheral area (APPH), while in surgical endoscopy, the surface of the surgical object and surrounding organs or tissues corresponds to the peripheral area (APPH). Furthermore, the peripheral area (APPH) can also be a region covered by medications or blood and not visible in the image IMG.

[0050] exist Figure 3The following example illustrates the spectral reflectance of the peripheral APPH region, showing the spectral reflectance of representative organs observed by endoscopy: the stomach, large intestine, and esophagus. Spectroscopic reflectance is the characteristic of reflectance relative to the wavelength of light, also known as spectral spectrum or spectrophotometry. Hereinafter, wavelengths such as 400 nm will be used.

[0051] like Figure 3 As shown, in the visible light wavelength region, there is a trend of the stomach exhibiting the highest reflectance and the esophagus the lowest. However, the spectral shapes of the stomach, esophagus, and large intestine are roughly the same. That is, there are spectral minimums near 420 nm and 550 nm, and a spectral maximum near 500 nm. Furthermore, above 600 nm, the spectra of the esophagus and large intestine generally increase monotonically. Additionally, the stomach spectrum has a maximum near 630 nm, and a slight decreasing trend in reflectance is observed at wavelengths longer than this maximum. In the large intestine spectrum, the increase in reflectance is slightly larger at wavelengths longer than 600 nm, but the reflectance in this region also increases in the stomach and esophagus, so it is not a significant characteristic.

[0052] When the region of interest (AINT) lacks spectroscopic characteristics compared to the surrounding region (APPH) as described above, i.e., when the difference in spectroscopic reflectance between the region of interest (AINT) and the surrounding region (APPH) is small, it is difficult to emphasize the region of interest (AINT) more by comparing it with the surrounding region (APPH) using spectroscopic methods.

[0053] Therefore, in this embodiment, the light source controller 150 controls the spectral shape of the illumination light based on spectral setting information based on the marker observation ratio, thereby relatively emphasizing the marker AMER compared to the surrounding area APPH. Alternatively, the image processing circuit 112 performs image processing to emphasize the marker based on the spectral setting information in the captured image (IMG) of the observed object, thereby relatively emphasizing the marker AMER compared to the surrounding area APPH.

[0054] The label-to-observation ratio refers to the ratio of the spectroscopic reflectance of the labeled AMER to the spectroscopic reflectance of the surrounding APPH region within each wavelength region of a segmented visible light wavelength region. For example, in... Figure 4 As described later, the multiple wavelength regions are violet, blue, green, amber, and red. The ratio of the spectroscopic reflectance of the marker AMER in each of these color regions to that of the surrounding APPH region is called the marker-observation ratio. It is sufficient that there are three or more wavelength regions.

[0055] Spectral setting information defines the spectral shape of the illumination light, representing the ratio of light intensity across the aforementioned wavelength regions. Figure 4In the example, the ratio of light intensity in the purple region RV, the blue region RB, the green region RG, the amber region RA, and the red region RR is spectral setting information. The light source controller 150 improves the visual recognizability of the AMER marker by emitting light from multiple light sources according to the light intensity ratios indicated by the spectral setting information. Alternatively, the image processing circuit 112 performs gain processing on the components of each wavelength region of an image illuminated by ordinary light, using a gain ratio corresponding to the light intensity ratios shown in the spectral setting information, thereby generating an image that resembles the illumination light illuminated by the light intensity ratios shown in the spectral setting information. This achieves image processing equivalent to marker emphasis based on illumination light. Here, gain processing refers to the process of amplifying or attenuating the components of each wavelength region of the captured image during image processing. The degree of amplification or attenuation is the gain ratio, which is set based on the light intensity ratios indicated by the spectral setting information.

[0056] According to this embodiment, the spectral shape of the illumination light is set based on spectral setting information of the marker observation ratio, or image processing is performed, thereby relatively emphasizing the marker AMER compared to the surrounding area APPH. This improves the visual recognizability of the marker AMER in the displayed image, making it easier for users to identify the presence of the area of ​​interest AINT accompanying the marker AMER.

[0057] Specifically, the ratio of the spectroscopic reflectance of the region of interest (AINT) to the spectroscopic reflectance of the surrounding region (APPH) within each wavelength region of the observed object is defined as the region of interest observation ratio. In this case, among the multiple wavelength regions, there exists a wavelength region where the deviation of the marked observation ratio from 1 is greater than the deviation of the region of interest observation ratio from 1. This wavelength region is designated as the i-th wavelength region. For example, when the visible light is divided into 5 segments, i is an integer greater than or less than 1 and less than 5. The deviation is the absolute value of the difference between the observation ratio and 1. That is, in the i-th wavelength region, the marked observation ratio can be greater than or less than 1, and the region of interest observation ratio can be greater than or less than 1.

[0058] A ratio of two spectroscopic reflectivities close to 1 means that the difference between the two spectroscopic reflectivities is small. In other words, it can be said that the further the marker observation ratio is from 1, the more spectroscopically distinctive the marker is relative to its surroundings. A greater deviation of the marker observation ratio from 1 than the deviation of the observation ratio of the area of ​​interest from 1 means that the spectroscopic characteristics of the marker AMER relative to the surrounding area APPH are greater than the spectroscopic characteristics of the area of ​​interest AINT relative to the surrounding area APPH.

[0059] In this embodiment, when the spectroscopic feature of the marker AMER is larger than that of the region of interest AINT, as described above, the visual recognizability of the marker AMER can be indirectly improved by improving the visual recognizability of the region of interest AINT, which has a smaller spectroscopic feature.

[0060] Furthermore, it can be said that the spectroscopic characteristics of the region of interest (AINT) are closer to those of the surrounding region (APPH) than those of the marker (AMER). That is, when the region of interest (AINT) is exposed, emphasizing the marker (AMER) and distinguishing it from the region of interest (AINT) in terms of spectroscopic characteristics increases the likelihood of relatively identifying the region of interest (AINT). For example, if the region of interest (AINT) is surrounded by the marker (AMER), like a nerve surrounded by fat, and there is an unemphasized area within the emphasized marker (AMER), it can be inferred that the region of interest (AINT) exists in that area.

[0061] Alternatively, in this embodiment, there may be a k-th wavelength region where the deviation of the marker observation ratio from 1 is greater than the deviation of the observation ratio of the region of interest from 1 among multiple wavelength regions. For example, when the visible light is divided into 5 segments, k is an integer greater than or equal to 1 and less than or equal to 5, and k ≠ i. In the k-th wavelength region, the marker observation ratio may be greater than or less than 1, and the region of interest observation ratio may be greater than or less than 1. Furthermore, the relationship between these observation ratios and 1 may differ from the relationship in the i-th wavelength region.

[0062] Thus, there can be two wavelength regions where the spectroscopic features of the AMER marker are greater than those of the AINT region of interest. Furthermore, by using the spectroscopic features from these two wavelength regions to improve the visual recognizability of the marker, the visual recognizability of the AINT region of interest, which has smaller spectroscopic features, can also be improved. Alternatively, there can be three or more wavelength regions where the spectroscopic features of the AMER marker are greater than those of the AINT region of interest, and the visual recognizability of the AMER marker can be improved by using the spectroscopic features from these three or more wavelength regions.

[0063] The definition of the markers is further detailed as follows: Components present in the tissues or organs surrounding the site of interest are defined as peripheral components. (A) Components whose areas of presence in the peripheral components roughly overlap with the site of interest are defined as site-of-interest index components. Furthermore, (B) Components whose areas of presence in the peripheral components are exclusive to the site of interest are defined as site-of-interest exclusive components. (C) Spectroscopic characteristic difference components are defined as follows: The difference between the average spectroscopic characteristics of the observed object and the spectroscopic characteristics of the spectroscopic characteristic difference components is greater than the difference between the spectroscopic characteristics of the site of interest and the spectroscopic characteristics of the spectroscopic characteristic difference components.

[0064] The marker is a component that satisfies (A) and (C), or a component that satisfies (B) and (C). The marker is also referred to as an indirect indicator component. Based on the characteristics of (A) or (B), it can be said that the marker indirectly represents the presence of the region of interest. Furthermore, it can be said that, due to the characteristics of (C), the visual recognizability of the image is more easily improved using a spectroscopic method compared to the region of interest. In this embodiment, by improving the visual recognizability of the marker, the visual recognizability of the region of interest can be indirectly improved.

[0065] To improve visual recognition by utilizing the characteristics of the markings described above, the spectral spectrum of the illumination light is set according to the spectral characteristics of the markings. That is, illumination light in wavelength regions where the spectral characteristics differ greatly between the markings and the surrounding areas is used. Furthermore, image processing is performed that emphasizes the wavelength regions with high spectral characteristics between the markings and the surrounding areas, based on the spectral characteristics of the markings. Either method can be used, or a combination of both can be employed.

[0066] As in Figure 2 As explained, the esophagus, stomach, and large intestine, which are the objects of endoscopy, have roughly similar reflectance spectral patterns, with tiny differences in magnitude and size resulting in variations in hue. For example, during treatment, it's desirable to simultaneously locate nerves and perform surgery, but the dispersive properties of nerves... Figure 4 The spectral characteristics of the esophagus, stomach, and large intestine are similar to those described later. Therefore, it is difficult to improve the visual recognition of the nerves through spectral methods. In the large intestine, the trend appears different at wavelengths longer than 630 nm, but biological tissues generally have high reflectivity in this wavelength region, thus appearing red. Therefore, it is difficult to improve visual recognition solely through illumination in the color region of wavelengths longer than 630 nm.

[0067] According to this embodiment, illumination light corresponding to the spectral characteristics of a mark contained in the observed object is irradiated onto the subject. Illumination light reflected or scattered by the subject is received, an image signal is constructed, and a visual recognition enhancement image of the mark is constructed based on the constructed image signal. According to the characteristics of (A) or (B), the area where the mark exists is correlated with the area of ​​interest. In addition, according to the characteristics of (C), compared with the area of ​​interest, the mark has a difference in spectral characteristics from the surrounding area, thus the visual recognition enhancement level is high. Therefore, by improving the visual recognition of the mark, the visual recognition of the area of ​​interest is indirectly improved. Therefore, compared with the case of directly improving the visual recognition of the area of ​​interest, the visual recognition enhancement level can be further improved.

[0068] In addition, since the marking is not the area of ​​interest itself, the endoscope device 10 can also have the functions described below.

[0069] The light source controller 150 may also set the spectral shape of the illumination light based on both the spectral characteristics of the marker and the spectral characteristics of the area of ​​interest. Alternatively, the image processing circuit 112 may set a wavelength region to be emphasized in image processing based on both the spectral characteristics of the marker and the spectral characteristics of the area of ​​interest. In this case, the spectral setting information is based on both the difference in spectral characteristics between the marker and surrounding areas and the difference in spectral characteristics between the area of ​​interest and surrounding areas.

[0070] By utilizing the spectroscopic features of the area of ​​interest, it is possible to expect improved visual recognizability of the marker, and specifically, improved visual recognizability of the area of ​​interest itself. That is, although the spectroscopic difference between the area of ​​interest and surrounding areas is small, by considering this difference, the area of ​​interest can be slightly emphasized in terms of spectroscopic representation relative to the surrounding areas.

[0071] Additionally, the endoscope device 10 may also have a marking emphasis mode to improve the visual recognizability of markings and a focus emphasis mode to emphasize areas of interest. For example, the control circuit 110 switches modes based on information input by the user from the operation unit 220 or the input unit 600. In this case, it may also be configured to allow switching sequentially between the marking emphasis mode, the focus emphasis mode, and the normal light observation mode via a single button. The normal light observation mode is a mode that observes the object using ordinary light such as white light.

[0072] Alternatively, multiple markers can be set. In this case, the light source controller 150 can set the spectral shape of the illumination light to simultaneously emphasize two or more of the markers, or it can set the spectral shape of the illumination light to emphasize one of the markers. Furthermore, the image processing circuit 112 can perform image processing either by simultaneously emphasizing two or more of the markers, or by emphasizing one of the markers. The endoscope device 10 can also have a mode that simultaneously emphasizes two or more markers and a mode that emphasizes one marker. In this case, the mode setting that allows setting which marker to emphasize can also be performed. For example, the control circuit 110 switches modes based on information input by the user from the operation unit 220 or the input unit 600. In this case, the mode can also be set to be switched sequentially using a single button.

[0073] Alternatively, the operation of the endoscope device 10 described above can also be implemented as an observation method. The observation method is based on observing the object of observation using reflected light from the object illuminated by the illumination light. In this observation method, the spectral shape of the illumination light is set according to spectral setting information based on the mark-to-observation ratio, and illumination light with the set spectral shape is generated, thereby relatively emphasizing the mark compared to surrounding areas. Alternatively, in the observation method, image processing for emphasizing the mark is performed based on the spectral setting information in the captured image of the object of observation, thereby relatively emphasizing the mark compared to surrounding areas. The above observation method can also be, for example, the operating method of the endoscope device 10. Furthermore, the operation of the endoscope device 10 in the first to fourth embodiments described below can also be implemented as an observation method.

[0074] 2. First Implementation Method

[0075] The following describes the detailed implementation method. Furthermore, the various implementation methods described below can be appropriately combined. The following description uses specific examples of parts of interest, etc., but these specific examples are merely one instance of parts of interest, etc., as long as they possess the features described above.

[0076] In the first embodiment, treatment around the large intestine will be described as an example. For instance, in a colonectomy, it is necessary to preserve the nerves around the surgical site. In the first embodiment, the site of interest is the nerve, the marker is β-carotene contained in fat that is likely to accompany the nerve, and the peripheral area is the large intestine and the organs or tissues surrounding it, which are the parts other than the nerves and fat. β-carotene is an example of a marker present near the site of interest, i.e., an example of a marker component of the site of interest.

[0077] It should be noted that the following explanation uses β-carotene as a marker, but the marker for nerves can be either fat or β-carotene. When fat is used as the marker, its spectrophotometric reflectance is used as the marker's spectrophotometric reflectance. Similarly, when β-carotene is used as the marker, its spectrophotometric reflectance is used as the marker's spectrophotometric reflectance. Since fat contains β-carotene, it has a yellowish hue compared to the surrounding area. β-carotene is known to represent the yellowish hue of the fat; therefore, its spectrophotometric reflectance is used as the marker's spectrophotometric reflectance.

[0078] Figure 4 This represents the spectral reflectance of the large intestine, fat, nerves, and β-carotene. The spectral reflectance of the large intestine is the spectral reflectance of the large intestine mucosa. Additionally, the spectral reflectance of fat is the spectral reflectance of the fat as a whole, including β-carotene.

[0079] like Figure 4As shown, the spectral reflectance of nerves is slightly higher than that of the large intestine across the entire visible light wavelength range, but exhibits a trend roughly similar to that of the large intestine mucosa. Specifically, the spectral reflectance of nerves has a minimum value between 400 nm and 450 nm, a maximum value near 500 nm, and increases at wavelengths longer than 600 nm.

[0080] Let the visible light wavelength region be 400nm ≤ λ ≤ 680nm, where λ is the wavelength. Divide this visible light wavelength region into the following 5 color regions.

[0081] Purple region RV: 400nm≤λ≤440nm

[0082] Blue region RB: 440nm < λ ≤ 495nm

[0083] Green region RG: 495nm<λ≤585nm

[0084] Amber region RA: 585nm < λ ≤ 615nm

[0085] Red region RR: 615nm < λ ≤ 680nm

[0086] The ratio of (spectral reflectance of the nerve) to (spectral reflectance of the large intestine) in each of the above color regions is called the attention area observation ratio. The spectral reflectance in a color region is the value obtained by integrating the spectral reflectance within that color region. As mentioned above, the spectral reflectances of the nerve and the large intestine show roughly the same trend, therefore the attention area observation ratio in the five color regions is roughly fixed. The attention area observation ratio in each color region is in the range of 1.0 to 2.0, indicating a small difference in the spectral characteristics between the nerve and the large intestine, and no spectral features that could enhance the visual recognition of the nerve are visible.

[0087] The spectral reflectance of fat located near nerves shows some differences compared to that of the large intestine, but the ratio of (spectral reflectance of fat) to (spectral reflectance of the large intestine) is between 0.8 and 2.0, indicating that the spectral characteristics of fat are not significantly different from those of the large intestine.

[0088] On the other hand, if we focus on β-carotene contained in fat, its spectroscopic properties are characteristic relative to those of the large intestine. The ratio of (spectral reflectance of β-carotene) to (spectral reflectance of the large intestine) is called the label-observation ratio. Figure 4As shown, the spectrophotometric reflectance of β-carotene is approximately zero in the wavelength range of 450 nm to 550 nm, and increases roughly monotonically above 550 nm. Therefore, the label-to-observation ratio is less than 1 / 10 in the blue region RB and the green region RG. Furthermore, the label-to-observation ratio is approximately 0.8 in the purple region RV, approximately 0.5 in the amber region RA, and approximately 0.9 in the red region RR. That is, light from the blue region RB and the green region RG, which have high label-to-observation ratios, is reflected by approximately 20%–40% in the large intestine, but only a few percent is reflected in β-carotene, essentially resulting in absorption. Therefore, in images based on light from the blue region RB and the green region RG, β-carotene is absorbed and appears darker, while the large intestine is depicted brightly in contrast.

[0089] Therefore, β-carotene is a marker, being both an (A) component indicating the site of interest and a (C) component indicating differences in spectroscopic properties. Furthermore, the light in the blue region RB and the green region RG can indirectly depict the light of nerves by depicting β-carotene present in fat. This type of light, which can indirectly depict the site of interest, is called visual recognition enhancement light. Additionally, the light in the amber region RA, while not as visual recognition enhancement light, can indirectly depict the site of interest. This type of light is called quasi-visual recognition enhancement light.

[0090] Specifically, light that enhances visual recognition is defined as follows. Light that does not enhance visual recognition is light that cannot be expected to improve visual recognition.

[0091] Visual recognition improved light: Marked-to-observation ratio < 0.3, or 3 < Marked-to-observation ratio

[0092] Quasi-visual recognition enhancement light: 0.3 < mark-to-observation ratio < 0.75, or 1.5 < mark-to-observation ratio < 3

[0093] Non-visual recognition enhancement light: 0.75 < mark-to-observation ratio < 1.5

[0094] The endoscope device 10 of this embodiment sets the spectral shape of the illumination light based on the spectral setting information of the marked observation ratio described above. A detailed structural example will be described below.

[0095] Figure 5 This is a detailed structural example of the light source unit 140 and the processing circuit 120. Figure 6 This is an example of the spectrum of the illumination light generated by the light source unit 140. Additionally, in Figure 5 Only the connector and light guide 214 of the mirror body 200 are shown in the figure; other structural elements are omitted.

[0096] The light source unit 140 includes light sources LDV, LDB, LDG, LDA, LDR, and a light combining unit 141. Additionally, the light source unit 140 may also include lenses for changing the light distribution of the light source or for parallelizing its light distribution.

[0097] like Figure 6 As shown, light source LDV emits light IV with a peak wavelength in the violet region RV. Similarly, light sources LDB, LDG, LDA, and LDR emit light IB, IG, IA, and IR with peak wavelengths in the blue region RB, green region RG, amber region RA, and red region RR, respectively. The intensity of the illumination light in the violet region RV is obtained by integrating the intensity of light IV in the violet region RV. Similarly, the intensity of the illumination light in the blue region RB, green region RG, amber region RA, and red region RR is obtained by integrating the intensity of light IB, IG, IA, and IR in the blue region RB, green region RG, amber region RA, and red region RR, respectively.

[0098] The light combining section 141 combines the light of the five colors and then directs it to the incident end of the light guide 214. The light combining section 141 is a dichroic filter DC1 to DC4 that combines the light of IV, IB, IG, IA, and IR. Alternatively, the light combining section 141 can also be an optical fiber or fiber bundle with five incident ends and one output end. The light incident on the light guide 214 is guided by the light guide 214 to the front end of the mirror and illuminates the subject.

[0099] LDV and LDB are InGaN-based LEDs. LDA and LDR are AlGaInP-based LEDs. LDG is a hybrid LED that uses an InGaN-based blue LED as excitation light, causing a phosphor coated on the LED's emitting surface to emit green light. Furthermore, these are just examples of light sources; various LEDs, semiconductor lasers, or hybrid light sources can be used.

[0100] The LEDs in the light sources LDV, LDB, LDA, and LDR each produce narrow wavelength light with a half-width of approximately 20–40 nm. The LED in the light source LDG emits a relatively wide wavelength light with a half-width of over 50 nm. The peak wavelengths of the light produced by the light sources LDV, LDB, LDG, LDA, and LDR are 415 nm, 460 nm, 540 nm, 600 nm, and 630 nm, respectively.

[0101] In addition to a marking emphasis mode that enhances the visual recognition of markings, the endoscope device 10 may also have a normal light observation mode and a special light observation mode. In the normal light observation mode, the light source unit 140 emits white light by emitting light from all five light sources at a predetermined color balance. In the special light observation mode, the light source unit 140 emits special light by emitting light from a predetermined light source among the five light sources at a predetermined light intensity ratio.

[0102] The following describes a method for improving the visual recognizability of areas of interest by grounding the marker in the middle of the emphasis pattern.

[0103] The ratio of spectral reflectance of β-carotene to spectral reflectance of the large intestine, or the marker-observation ratio, is approximately 0.8–0.9 in the purple region (RV) and red region (RR), which is close to 1. Therefore, the improvement in visual recognition by light sources LDV and LDR is small. Furthermore, since the marker-observation ratio in the amber region (RA) is approximately 0.5, light source LDA can improve visual recognition to some extent, but the effect is limited compared to light sources LDB and LDG. Because the marker-observation ratio in the blue region (RB) and green region (RG) is only a fraction of a percent, which is very small, light sources LDB and LDG can be expected to improve visual recognition. In other words, in an image based on illumination light of this wavelength, the reflected light from the large intestine tissue, which is a peripheral region, accounts for approximately 20% to 40%, while the reflected light from β-carotene, the marker, is less than a few percent. Therefore, when observing an image of the large intestine surface containing β-carotene, only β-carotene is depicted darker. Since β-carotene is a marker for nerves, the area near nerves is depicted darker.

[0104] Memory 114 stores spectral setting information based on the aforementioned marked observation ratio. Memory 114 is a semiconductor memory such as RAM or non-volatile memory. Control circuit 110 reads the spectral setting information from memory 114 and transmits it to light source controller 150. Light source controller 150 sets the light intensity ratios of light sources LDV, LDB, LDG, LDA, and LDR based on the spectral setting information. Several examples of light intensity ratio settings will be described below. Hereinafter, the light intensity ratios will be recorded as a:b:c:d:e, where a, b, c, d, and e correspond to light sources LDV, LDB, LDG, LDA, and LDR, respectively.

[0105] Figure 7 The first example represents the light intensity ratio. In this first example, the light source controller 150 illuminates the light sources LDB and LDG that emit light that enhances visual recognition, while extinguishing the light sources LDV, LDA, and LDR. For example, the spectral setting information is a light intensity ratio of 0:1:1:0:0, but the light intensity ratio of the light sources LDB and LDG is not limited to 1:1.

[0106] Based on the first example, in the captured images, the surface of the large intestine could be depicted as blue-green, and beta-carotene as black. Thus, the increased visual recognition of beta-carotene as black indirectly improved the visual recognition of the nerves.

[0107] Figure 8 The second example represents the light intensity ratio. In this second example, the light source controller 150 causes the light sources LDB, LDG, and LDA, which emit quasi-visual recognition-enhancing light, to emit light, while turning off the light sources LDV and LDR. For example, the spectral setting information is a light intensity ratio of 0:1:1:1:0, but the light intensity ratio of the light sources LDB, LDG, and LDA is not limited to 1:1:1.

[0108] According to the second example, the surface of the large intestine can be depicted in relatively natural colors of blue, green, and amber, and β-carotene can be depicted as a dark amber color. By setting the light intensity ratio of the light source LDB, LDG, and LDA to approximately 1:1:1, it is possible to make the image of the large intestine a hue that is closer to that when the large intestine is observed under ordinary light.

[0109] Figure 9 This is a third example of the light intensity ratio. In this third example, the light source controller 150 causes all four light sources—LDV, LDB, LDG, LDA, and LDR—to emit light. The LDV and LDR light sources contribute almost nothing to improving the visual recognition of β-carotene, but they also have almost no adverse effect on the visual recognition of β-carotene. On the other hand, by causing the LDV and LDR light sources to emit light, the color tone of the large intestine can be made closer to the color tone observed under ordinary light. For example, the spectral setting information is a light intensity ratio of 0.5∶1∶1.5∶0.9∶0.6. However, the RGB light intensity ratio, i.e., (the light emission of LDV and LDB light sources): (the light emission of LDG light sources): (the light emission of LDA and LDR light sources), can be approximately 1:1:1. Furthermore, while both LDV and LDR light sources are emitted in the above example, it is also possible to emit only one of the LDV and LDR light sources.

[0110] According to the third example, by using one or both of the light sources LDV and LDR, it is possible to approximate the hue observed under ordinary light while maintaining the effect of improving the visual recognizability of the marking. That is, the large intestine can exhibit color representation approximately the same as under ordinary light, and β-carotene is depicted using red, the color obtained by removing green and blue from the five colors. In this case, by setting the luminous intensity of LDV ≈ luminous intensity of LDR < luminous intensity of LDA < luminous intensity of LDG ≈ luminous intensity of LDB, the effect of improving visual recognizability can be enhanced. Furthermore, when dividing visible light into RGB, by making their ratio approximately 1:1:1, a natural image close to that of an ordinary light image can be obtained.

[0111] According to the above embodiment, when the mark-observation ratio in the k-th wavelength region is less than the mark-observation ratio in the j-th wavelength region, the light source controller 150 makes the emitted light quantity of the k-th light source greater than the emitted light quantity of the j-th light source. The k-th wavelength region is a wavelength region where the mark-observation ratio is less than 1 and less than the observation ratio of the area of ​​interest.

[0112] In the first embodiment, k and j are integers greater than or equal to 1 and less than or equal to 5. For example, the color region RV, blue region RB, green region RG, amber region RA, and red region RR can be designated as the first, second, third, fourth, and fifth wavelength regions, respectively. Correspondingly, the light sources LDV, LDB, LDG, LDA, and LDR can be designated as the first, second, third, fourth, and fifth light sources, respectively. The k-th wavelength region is either the blue region RB, the green region RG, or the amber region RA, and the j-th wavelength region is either the violet region RV or the red region RR. In any of the first to third examples described above, the emitted light intensity of light sources LDB and LDG is greater than that of light sources LDV and LDR. Furthermore, in the second and third examples, the emitted light intensity of light source LDA is greater than that of light sources LDV and LDR.

[0113] In addition, the light source controller 150 can also make the emitted light quantity of the i-th light source greater than that of the j-th light source when the deviation of the mark observation ratio from 1 in the i-th wavelength region is greater than the deviation of the mark observation ratio from 1 in the j-th wavelength region.

[0114] As described above, the further the wavelength range from which the marker's observation ratio is 1, the greater the light intensity of the light source emitting light from that wavelength range will be. It is believed that the further the marker's observation ratio is from the wavelength range of 1, the better the visual recognition will be. Therefore, according to this embodiment, by increasing the light intensity for wavelength ranges further from the marker's observation ratio of 1, the visual recognition of the marker can be improved, indirectly alerting the user to the presence of the area of ​​interest.

[0115] The processing circuit 120 in this embodiment includes a memory 114 for storing spectral setting information. The light source controller 150 sets the emitted light amount of each light source based on the spectral setting information stored in the memory 114.

[0116] In this way, spectral setting information can be pre-generated based on the marked observation ratio and stored in the memory 114, and the light intensity ratio can be set based on the spectral setting information. Alternatively, the user can input spectral setting information via the input unit 600, store the spectral setting information in the memory 114, and set the light intensity ratio based on the spectral setting information.

[0117] In addition, in this embodiment, the multiple light sources included in the light source unit 140 are a purple light source (LDV) that emits light in the purple region RV, a blue light source (LDB) that emits light in the blue region RB, a green light source (LDG) that emits light in the green region RG, an amber light source (LDA) that emits light in the amber region RA, and a red light source (LDR) that emits light in the red region RR.

[0118] In this way, by using multiple independent light sources that emit light from each color region, the amount of light in each color region can be set independently. As a result, the spectral shape of the illumination light can be freely set, and the optimal spectral shape of the illumination light can be achieved while improving the visual recognizability of the markings.

[0119] In addition, in this embodiment, the light source controller 150 makes the emitted light amount of the blue light source and the green light source greater than the emitted light amount of the violet light source and the red light source.

[0120] In this way, when the area of ​​interest is a nerve, the marker is beta-carotene, and the surrounding area is mucous membrane, the marker can be relatively emphasized relative to the surrounding area. This improves the visual recognizability of the marker, thus indirectly alerting the user to the presence of the nerve as the area of ​​interest.

[0121] 3. A first variation of the first embodiment

[0122] The emphasis on the markings in the first embodiment can also be achieved through image processing. Figure 10 This is a diagram illustrating the image processing in the first variation.

[0123] The light source controller 150 causes the light source unit 140 to emit white light. For example, the white light is light from five light sources with a light intensity ratio of approximately 1:1:1:1:1. Alternatively, the white light may be light with a light intensity ratio similar to that of a xenon lamp. The image processing circuit 112 generates a normal light image IMIN based on the image signal input from the imaging unit 213.

[0124] The control circuit 110 reads the spectral setting information from the memory 114 and transmits it to the image processing circuit 112. The components in the ordinary light image IMIN corresponding to the violet region RV, blue region RB, green region RG, amber region RA, and red region RR are respectively designated as violet component VIM, blue component BIM, green component GIM, amber component AIM, and red component RIM. The image processing circuit 112 extracts the color components VIM, BIM, GIM, AIM, and RIM from the ordinary light image and performs gain processing on each color component based on the spectral setting information. For example, the image processing circuit 112 converts the RGB ordinary light image into a YCrCb image and extracts each color component based on the hue values ​​of the YCrCb image.

[0125] Taking the spectral setting information as a light intensity ratio of 0.5∶1∶1.5∶0.9∶0.6 as an example, the image processing circuit 112 multiplies the color components VIM, BIM, GIM, AIM, and RIM by gains corresponding to the light intensity ratio: VGN = 0.5, BGN = 1, GGN = 1.5, AGN = 0.9, and RGN = 0.6. The image processing circuit 112 then converts the gain-processed YCrCB image into an RGB image and outputs this RGB image as the output image IMQ.

[0126] The output image IMQ is an image equivalent to one captured when the light intensity ratio of the light source unit 140 is controlled based on spectral setting information. That is, through the image processing described above, the visual recognizability of the marker can be improved in the same way as when the light intensity ratio of the light source unit 140 is controlled.

[0127] According to this embodiment, when the deviation of the marker observation ratio from 1 in the i-th wavelength region is greater than the deviation of the marker observation ratio from 1 in the j-th wavelength region, the image processing circuit 112 makes the gain of the i-th wavelength component among the multiple wavelength components of the captured image greater than the gain of the j-th wavelength component. The meanings of i and j are as explained in the first embodiment.

[0128] In this embodiment, it is sufficient to set the purple, blue, green, amber, and red components of the captured image as the first, second, third, fourth, and fifth wavelength components, respectively. In the image processing corresponding to the first to third examples described in the first embodiment, the gain for the blue and green components is greater than the gain for the purple and red components. Furthermore, in the image processing corresponding to the second and third examples, the gain for the amber component is greater than the gain for the purple and red components.

[0129] As described above, the image processing circuit 112 is configured such that the gain for the components in the wavelength region further away from the observed wavelength by 1 is greater. By increasing the gain for the components in the wavelength region further away from the observed wavelength by 1, the visual recognizability of the marker can be improved, and the presence of the area of ​​interest can be indirectly indicated to the user.

[0130] Furthermore, in this embodiment, the image processing circuit 112 sets the gain for each wavelength component of the multiple wavelength components based on the spectral setting information stored in the memory 114.

[0131] In this way, spectral setting information can be pre-generated based on the marked observation ratio and stored in memory 114, and the gain of each wavelength component can be set based on the spectral setting information. Alternatively, the user can input spectral setting information via input unit 600, store the spectral setting information in memory 114, and set the gain of each wavelength component based on the spectral setting information.

[0132] Furthermore, in this embodiment, the image processing circuit 112 makes the gain for the blue and green components greater than the gain for the purple and red components.

[0133] In this way, when the area of ​​interest is a nerve, the marker is β-carotene, and the surrounding area is mucous membrane, the marker can be relatively emphasized relative to the surrounding area through image processing. This improves the visual recognizability of the marker, thus indirectly prompting the user about the presence of the nerve as the area of ​​interest.

[0134] Furthermore, this explanation uses the case of a simultaneous imaging element (Bayer type) with five light sources emitting light simultaneously as an example, but the same method can also be applied to a sequential surface type. The sequential surface type will be explained in the third and fourth embodiments.

[0135] 4. A second variation of the first embodiment

[0136] In the first embodiment, the spectral shape of the illumination light is set by taking into account the difference in spectral reflectance between β-carotene, which is a marker, and the large intestine, which is a peripheral part. However, in the second variation, the spectral shape of the illumination light is also set by taking into account the difference in spectral reflectance between the nerve, which is a site of interest, and the large intestine, which is a peripheral part.

[0137] like Figure 4 As shown, the ratio of (spectral reflectance of nerves) to (spectral reflectance of the large intestine) observed at the site of interest is approximately 2.0 in the purple and blue regions, approximately 1.3 in the green region, approximately 1.5 in the amber region, and approximately 1.0 in the red region. That is, the light in the purple, blue, and amber regions is quasi-visual recognition-enhancing light for nerves. For β-carotene, the light in the blue and green regions is visual recognition-enhancing light, while the light in the amber region is quasi-visual recognition-enhancing light. Therefore, the light in the blue and amber regions can directly or indirectly enhance the visual recognition of nerves. Furthermore, the light in the purple region has a limited effect on enhancing the visual recognition of β-carotene, but it can still enhance the visual recognition of nerves.

[0138] Figure 11 The table summarizes the above-mentioned effects on improving visual recognition. 〇 represents light that improves visual recognition, △ represents light that improves quasi-visual recognition, and × represents light that improves non-visual recognition.

[0139] Based on the above, by setting the light intensity of LDR < LDV < LDA ≈ LDG < LDB, the visual recognition of both nerves and β-carotene can be improved. However, if the light intensity ratio of illumination light, which is close to white light, is also considered, the light intensity ratio is, for example, 0.6∶1.2∶1.8∶1.4∶0.4. In this case, the light intensity ratio of RGB is 1∶1∶1.

[0140] Similar to the first variation, the image processing circuit 112 performs gain processing on each color component of the captured image corresponding to the above-mentioned light intensity ratio, thereby obtaining an image equivalent to the second variation.

[0141] According to this embodiment, the light source controller 150 sets the spectral shape of the illumination light based on spectral setting information based on the observation ratio of the area of ​​interest, thereby relatively emphasizing the area of ​​interest compared to the surrounding areas. Alternatively, the image processing circuit 112 performs image processing to emphasize the area of ​​interest based on the aforementioned spectral setting information in the captured image, thereby relatively emphasizing the area of ​​interest compared to the surrounding areas.

[0142] In this way, the marking not only provides relative emphasis compared to the surrounding areas, but also, although the degree of emphasis is lower, it still provides relative emphasis to the area of ​​interest relative to the surrounding areas. Therefore, it can not only indirectly improve the visual recognizability of the area of ​​interest through marking emphasis, but also directly improve the visual recognizability of the area of ​​interest.

[0143] 5. A third variation of the first embodiment

[0144] In the first embodiment, the spectral shape of the illumination light is set by considering the difference in spectral reflectance between β-carotene, which is a marker, and the large intestine, which is a peripheral area. However, in the third variation, the spectral shape of the illumination light is also set by considering the difference in spectral reflectance between the nerve, which is a site of interest, and β-carotene, which is a marker.

[0145] like Figure 4As shown, the ratio of (spectral reflectance of nerve) to (spectral reflectance of β-carotene) observed at the site of interest is approximately 2.5 in the purple region, several tens in the blue and green regions, approximately 3.0 in the amber region, and approximately 0.9 in the red region. That is, light in the blue, green, and amber regions is visually enhancing light that improves the visual recognition of nerves relative to β-carotene. Additionally, light in the purple region is quasi-visually enhancing light that improves the visual recognition of nerves relative to β-carotene. In other words, light in the blue, green, and amber regions can relatively improve the visual recognition of nerves relative to β-carotene. In contrast, although the effect is lower, light in the purple region can also relatively improve the visual recognition of nerves relative to β-carotene.

[0146] Based on the above, by setting the light intensity of LDR < LDV < LDB ≈ LDG ≈ LDA, it is possible to relatively improve the visual recognition of nerves relative to both β-carotene and the large intestine. However, if we also consider the light intensity ratio as near-white light, for example, a ratio of 0.4:1.4:1.8:1.6:0.2, then the RGB light intensity ratio is 1:1:1.

[0147] Similar to the first variation, the image processing circuit 112 performs gain processing on each color component of the captured image in accordance with the above-mentioned light intensity ratio, thereby obtaining an image equivalent to the third variation.

[0148] According to this embodiment, the light source controller 150 sets the spectral shape of the illumination light based on spectral setting information of the observation ratio of the marked area of ​​interest, thereby emphasizing the area of ​​interest relative to the marked area. Alternatively, the image processing circuit 112 performs image processing to emphasize the area of ​​interest based on the aforementioned spectral setting information in the captured image, thereby emphasizing the area of ​​interest relative to the marked area.

[0149] In this way, not only is the marker relatively emphasized relative to the surrounding areas, but even with a lower degree of emphasis, the area of ​​interest is still relatively emphasized relative to the marker. Therefore, the visual recognizability of the area of ​​interest is improved not only indirectly through marker emphasis but also directly. For example, consider the presence and absence of nerves within fat. In such cases, by relatively emphasizing the area of ​​interest relative to the marker, the visual recognizability of whether the area of ​​interest actually exists within the marked area is improved.

[0150] 6. Second Implementation Method

[0151] Next, the second embodiment will be described. The detailed structure of the endoscope device 10, the light source unit 140, and the processing circuit 120 will be described in conjunction with... Figure 1 , Figure 5 The same. In the second embodiment, the differences from the first embodiment will be mainly explained.

[0152] In the second embodiment, the case of Lugol's staining during esophageal cancer examination will be described as an example. Lugol's staining is a surgical procedure performed to improve visual identification in the detection of esophageal cancer. Lugol's solution is difficult to adhere to esophageal cancer, but adheres to areas outside the esophageal cancer; therefore, unstained areas in areas without Lugol's solution may indicate esophageal cancer. In Lugol's staining, confirming the boundary between cancer and normal tissue is important. In this embodiment, a method for visually confirming the boundary between Lugol's solution and normal tissue with good identification will be described. In the second embodiment, the site of interest is esophageal cancer, the marker is Lugol's solution, and the surrounding area is the esophageal mucosa. Lugol's solution is an example of a marker that is exclusively present near the site of interest, that is, an example of an exclusive component of the site of interest.

[0153] Figure 12 This represents the spectrophotometric reflectance of the esophagus and Lugol's mucosa. The spectrophotometric reflectance of the esophagus is the reflectance of the esophageal mucosa without Lugol's staining.

[0154] In the second embodiment, the labeled observation ratio is (Lugol's spectrophotometric reflectance) / (esophageal spectrophotometric reflectance). For example... Figure 8 As shown, the labeled observation ratio is approximately 2.5 in the purple region (RV), approximately 1.0 in the blue region (RB), approximately 1.8 in the green region (RG), approximately 2.0 in the amber region (RA), and approximately 1.2 in the red region (RR). That is, the light in the purple region (RV), green region (RG), and amber region (RA) is the quasi-visual recognition-enhancing light, which improves the visual recognition of Lugol's resemblance to the esophagus. Furthermore, since cancerous tissue has a spectrophotometric reflectance spectrum approximately the same as that of the esophagus, it is difficult to identify it as normal esophageal tissue. Specifically, the site-of-interest observation ratio, which is (spectral reflectance of esophageal cancer) / (spectral reflectance of the esophagus), is approximately 1 in each color region, closer to 1 than the labeled observation ratio.

[0155] The following describes several examples of light intensity ratio settings. The light intensity ratio will be denoted as a:b:c:d:e, where a, b, c, d, and e correspond to the light sources LDV, LDB, LDG, LDA, and LDR, respectively.

[0156] Figure 13The first example represents the light intensity ratio. In this first example, the light source controller 150 illuminates the light sources LDV, LDG, and LDA that emit light that enhances visual recognition, while extinguishing the light sources LDB and LDR. For example, the spectral setting information is a light intensity ratio of 1:0:1:1:0, but the light intensity ratio of the light sources LDV, LDG, and LDA is not limited to 1:1:1.

[0157] According to the first example, by improving the visual recognizability of Lugol's blotch relative to the esophageal mucosa, the visual recognizability of esophageal cancer as the site of interest can be improved. That is, since esophageal cancer and esophageal mucosa have similar spectroscopic spectra, esophageal cancer and Lugol's blotch can be distinguished by spectroscopic differentiation of the esophageal mucosa and Lugol's blotch. Since Lugol's blotch is attached to normal mucosa, the boundary between esophageal cancer and normal mucosa is easily visually recognized. It should be noted that in this embodiment, only the quasi-visual recognizability-enhancing light is used, but since the label-to-observation ratio is ensured to be 1.8 or higher, sufficient effect can be expected.

[0158] Figure 14 The second example illustrates the light intensity ratio. In this second example, the light source controller 150 causes all light sources LDV, LDB, LDG, LDA, and LDR to emit light. Light sources LDB and LDR contribute almost nothing to improving Lugol's visual recognition, but they also have almost no adverse effect on Lugol's visual recognition. On the other hand, by causing light sources LDB and LDR to emit light, the hue of the esophageal mucosa and esophageal cancer can be made closer to the hue observed under ordinary light. For example, the spectral setting information is a light intensity ratio of 1:0.5:1.5:1:0.5. However, it is sufficient if the RGB light intensity ratio is approximately 1:1:1. Furthermore, while both light sources LDB and LDR emit light as described above, it is also possible to cause only one of the light sources LDB or LDR to emit light.

[0159] According to the second example, by using one or both of the light sources LDB and LDR, it is possible to approximate the hue observed under ordinary light while maintaining the effect of improving the visual recognizability of the mark. In this case, by making the luminous intensity of LDB ≈ luminous intensity of LDR < luminous intensity of LDV ≈ luminous intensity of LDG ≈ luminous intensity of LDA, the improvement in visual recognizability can be achieved. Furthermore, when dividing visible light into RGB, by making their ratio approximately 1:1:1, a natural image close to that of ordinary light can be obtained.

[0160] In addition, similar to the first variation of the first embodiment, the image processing circuit 112 performs gain processing on each color component of the captured image corresponding to the above-mentioned light intensity ratio, thereby obtaining an image equivalent to that of the second embodiment.

[0161] According to the above embodiment, the light source controller 150 makes the emitted light amount of the violet light source (LDV), green light source (LDG), and amber light source (LDA) greater than the emitted light amount of the blue light source (LDB) and red light source (LDR).

[0162] Alternatively, in this embodiment, the image processing circuit 112 may also make the gain for the purple, green and amber components greater than the gain for the blue and red components.

[0163] In this way, when the site of interest is esophageal cancer, the marker is Lugol's marker, and the surrounding area is the esophageal mucosa, the marker can be relatively emphasized relative to the surrounding area. This improves the visual recognition of esophageal cancer, which is the site of interest and whose spectroscopic features are similar to those of Lugol's marker.

[0164] 7. Third Implementation Method

[0165] In the first and second embodiments, all five light sources emit light simultaneously; however, in the third embodiment, the five light sources emit light sequentially. The method of emitting light sources sequentially, capturing images of each light source emitting light, and then synthesizing a color image from these images is called the sequential illumination method. The structure of the endoscope device 10 is similar to... Figure 1 The same. In the third embodiment, the differences from the first and second embodiments will be mainly explained.

[0166] Figure 15 This is a detailed structural example of the processing circuit 120 in the third embodiment. The structure of the light source unit 140 is the same as in the first embodiment. In the third embodiment, the processing circuit 120 also includes an image memory 116.

[0167] The light source controller 150 causes the light sources LDV, LDB, LDG, LDA, and LDR to emit light sequentially. For example, the light source controller 150 illuminates them in the order of LDV, LDB, LDG, LDA, and LDR, but the order is not limited to this. The camera unit 213 captures images at the moment each light source emits light.

[0168] Figure 16 This diagram illustrates the image processing in the third embodiment. The image processing circuit 112 generates the image VIMIN based on the image signal acquired by the imaging unit 213 during the emission of light at LDV. Similarly, the image processing circuit 112 generates the images BIMIN, GIMIN, AIMIN, and RIMIN based on the image signals acquired by the imaging unit 213 during the emission of light at LDB, LDG, LDA, and LDR. The images VIMIN, BIMIN, GIMIN, AIMIN, and RIMIN correspond to the wavelength components corresponding to the wavelength regions RV, RB, RG, RA, and RR, respectively.

[0169] Image memory 116 temporarily stores sequentially generated images VIMIN, BIMIN, GIMIN, AIMIN, and RIMIN. Image memory 116 is a semiconductor memory such as RAM.

[0170] Image processing circuit 112 multiplies the images VIMIN, BIMIN, GIMIN, AIMIN, and RIMIN read from image memory 116 by gains VGN, BGN, GGN, AGN, and RGN corresponding to the light intensity ratio. Image processing circuit 112 then synthesizes the five images after gain processing and outputs the result as the output image IMQ.

[0171] In normal light observation mode, the image processing circuit 112 generates a white light image as the output image IMQ by using a gain corresponding to the spectrum of white light.

[0172] In the marker emphasis mode, the image processing circuit 112 generates an output image IMQ in which the marker is emphasized by using a gain corresponding to the light intensity ratio described in the first embodiment or the light intensity ratio described in the second embodiment. The light intensity ratio used for marker emphasis is the same as that described in the first and second embodiments. Similar to the effects described in the first and second embodiments, in the third embodiment, by relatively improving the visual recognizability of the marker relative to the surrounding areas, the visual recognizability of the area of ​​interest can also be indirectly improved.

[0173] In addition, Figure 16 In this example, each of the five images is multiplied by a gain, but the image processing method is not limited to this. For example, it is also possible to select images with non-zero gain instead of images with zero gain, and then multiply the selected images by a gain.

[0174] In addition, Figure 16 While image processing was used for marker emphasis, it can also be achieved by setting the light intensity ratio. That is, the light source controller 150 can also perform marker emphasis by sequentially emitting light from each light source using the light intensity ratio described in the first and second embodiments.

[0175] 8. Fourth Implementation Method

[0176] In the third embodiment, the five light sources emit light sequentially; however, in the fourth embodiment, the five light sources are divided into three groups, and each group emits light sequentially. The structure of the endoscope device 10 is similar to... Figure 1 Similarly, the detailed structure of the light source unit 140 and the processing circuit 120 is the same as... Figure 15 The same. In the fourth embodiment, the differences from the first to third embodiments will be mainly explained.

[0177] The light source controller 150 causes the light sources LDV and LDB (as the first group), LDG (as the second group), and LDA and LDR (as the third group) to emit light one group at a time. When the visible light wavelength region is divided into three regions (RGB), the first group corresponds to region B, the second group to region G, and the third group to region R. For example, the light source controller 150 illuminates each group in the order of the first, second, and third groups, but the order is not limited to this. The camera unit 213 captures images when each group emits light.

[0178] Image processing circuit 112 generates a B image based on the image signal obtained by camera unit 213 during the illumination timing of the first group. Similarly, image processing circuit 112 generates G and R images based on the image signals obtained by camera unit 213 during the illumination timing of the second and third groups. Image memory 116 temporarily stores the sequentially generated B, G, and R images. Image processing circuit 112 synthesizes the B, G, and R images read from image memory 116 and outputs the result as the output image IMQ.

[0179] The light source controller 150 causes the light sources LDV, LDB, LDG, LDA, and LDR to emit light sequentially in each group according to the light intensity ratio described in the first embodiment or the light intensity ratio described in the second embodiment.

[0180] In the fourth embodiment, similar to the effects described in the first and second embodiments, the visual recognizability of the mark is indirectly improved by relatively enhancing the visual recognizability of the area of ​​interest relative to the surrounding areas. Furthermore, since the third embodiment uses five surfaces sequentially and the fourth embodiment uses three surfaces sequentially, the fourth embodiment is less susceptible to the effects of subject motion shake. Therefore, the fourth embodiment is less likely to produce a sense of incongruity in image motion.

[0181] Furthermore, while the above description only uses the light intensity ratio for emphasis marking, it is also possible to combine light intensity ratio and image processing for emphasis marking. That is, the light source controller 150 only controls the light intensity ratio within each group, not the light intensity ratio between groups. Specifically, the light source controller 150 controls the light intensity ratios of light sources LDV and LDB, and LDA and LDR, respectively, based on spectral setting information, but causes light source LDG to emit light at a predetermined intensity regardless of the spectral setting information. The image processing circuit 112 multiplies the gain of the light intensity ratio between the reproduction groups by the B image, G image, and R image, and generates an output image by synthesizing the multiplied images.

[0182] The embodiments and variations thereof applying the present invention have been described above. However, the present invention is not directly limited to each embodiment and variation thereof. During the implementation stage, the constituent elements can be modified and embodied without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple constituent elements disclosed in the above-described embodiments and variations. For example, several constituent elements may be deleted from all the constituent elements described in each embodiment and variation. Furthermore, constituent elements described in different embodiments and variations may be appropriately combined. In this way, various modifications and applications can be made without departing from the spirit of the invention. In addition, in the specification or drawings, a term described at least once with a different term that is more general or synonymous can be replaced with that different term at any point in the specification or drawings.

[0183] Label Explanation

[0184] 10 Endoscope device, 100 Control device, 110 Control circuit, 112 Image processing circuit, 114 Memory, 116 Image memory, 120 Processing circuit, 140 Light source unit, 141 Photosynthesis unit, 150 Light source controller, 200 Endoscope body, 210 Insertion unit, 211, 212 Illumination lenses, 213 Camera unit, 214 Light guide, 215 Image signal line, 220 Operation unit, 230 Connecting cable, 240 Connector, 300 Display unit, 600 Input unit, AGN Gain, AINT Area of ​​Interest, AMER Mark, APPH Peripheral Area, IMG Image Capture, LDA, LDB, LDG, LDR, LDV Light Source, RA Amber Area, RB Blue Area, RG Green Area, RR Red Area, RV Purple Area

Claims

1. A light source device that generates illumination light to illuminate an object being observed, characterized in that, The light source device includes: The first light source emits light with a peak wavelength in the first wavelength region; A second light source emits light with a peak wavelength in a second wavelength region; and processor, The processor controls the emitted light amounts of the first and second light sources based on spectral setting information, such that the emitted light amount of the first light source is greater than the emitted light amount of the second light source. The observed object includes a region of interest, a marker, and a surrounding region. The marker is a component existing outside the region of interest but in a region related to the region where the region of interest is located. The surrounding region is a region outside the region of interest and does not contain the marker. The spectral setting information is set based on the marked observation ratio. The marker observation ratio is the ratio of the spectral reflectance of the marker in each wavelength region to the spectral reflectance of the surrounding area, wherein each wavelength region is one of multiple wavelength regions divided from the visible light wavelength region. The deviation of the marker observation ratio from 1 in the first wavelength region is greater than the deviation of the marker observation ratio from 1 in the second wavelength region.

2. The light source device according to claim 1, characterized in that, When the ratio of the spectral reflectance of the region of interest within each wavelength region to the spectral reflectance of the surrounding region is used as the observation ratio of the region of interest,... In the first wavelength region, the deviation of the marker observation ratio from 1 is greater than the deviation of the observation ratio of the area of ​​interest from 1.

3. The light source device according to claim 2, characterized in that, In the second wavelength region, the deviation of the marker observation ratio from 1 is greater than the deviation of the observation ratio of the area of ​​interest from 1.

4. The light source device according to claim 1, characterized in that, The light source device also includes a memory for storing the spectral setting information. The processor sets the emitted light amount of the first light source and the second light source according to the spectral setting information stored in the memory.

5. The light source device according to claim 1, characterized in that, The multiple wavelength regions are the violet region, the blue region, the green region, the amber region, and the red region.

6. The light source device according to claim 5, characterized in that, The area of ​​interest is the nerve, the marker is β-carotene, and the surrounding area is the mucous membrane. The processor causes the output light quantity of the blue light source emitting light from the blue region and the green light source emitting light from the green region to be greater than the output light quantity of the violet light source emitting light from the violet region and the red light source emitting light from the red region.

7. The light source device according to claim 5, characterized in that, The area of ​​interest is esophageal cancer, the marker is Lugol's solution, and the surrounding area is the esophageal mucosa. The processor causes the emitted light quantities of the violet light source emitting light from the violet region, the green light source emitting light from the green region, and the amber light source emitting light from the amber region to be greater than the emitted light quantities of the blue light source emitting light from the blue region and the red light source emitting light from the red region.

8. The light source device according to claim 1, characterized in that, The marked observation ratio of light in the first wavelength region is less than 0.75 or greater than 1.

5.

9. The light source device according to claim 1, characterized in that, The first wavelength region is green, and the second wavelength region is blue.

10. The light source device according to claim 1, characterized in that, The light source device further includes a third light source that emits light with a peak wavelength in the blue region, which is a third wavelength region. The first wavelength region is green. The second wavelength region is red.

11. The light source device according to claim 1, characterized in that, When the ratio of the spectral reflectance of the region of interest to the spectral reflectance of the surrounding region in each wavelength region is used as the observation ratio of the region of interest, The processor sets the spectral shape of the illumination light based on the spectral setting information based on the observation ratio of the region of interest, thereby relatively emphasizing the region of interest compared to the surrounding regions, or... In the image obtained by photographing the observed object, the processor performs image processing to emphasize the region of interest based on the spectral setting information, thereby relatively emphasizing the region of interest compared with the surrounding region.

12. The light source device according to claim 1, characterized in that, When the ratio of the spectroscopic reflectance of the marker in each wavelength region to the spectroscopic reflectance of the region of interest is used as the marker-to-region observation ratio, The processor sets the spectral shape of the illumination light based on the spectral setting information of the observation ratio of the marker to the region of interest, thereby relatively emphasizing the marker compared to the region of interest, or... In the image obtained by photographing the observed object, the processor performs image processing to emphasize the mark according to the spectral setting information, thereby relatively emphasizing the mark compared with the area of ​​interest.

13. An endoscope system comprising: Endoscope, This endoscope uses a camera element to observe the object being examined; And a control device that generates illumination light to illuminate the object being observed, characterized in that the endoscope system comprises: The first light source emits light with a peak wavelength in the first wavelength region; A second light source emits light with a peak wavelength in a second wavelength region; and processor, The processor controls the emitted light amounts of the first and second light sources based on spectral setting information, such that the emitted light amount of the first light source is greater than the emitted light amount of the second light source. The processor generates an output image that relatively emphasizes the mark compared to the surrounding area based on an image signal, wherein the image signal is an image signal output from the imaging element that captures the observed object illuminated by the illumination light. The object of observation includes the region of interest, the marker, and the surrounding region. The marker is a component existing outside the region of interest but in a region related to the region where the region of interest is located. The surrounding region is a region outside the region of interest and does not contain the marker. The spectral setting information is set based on the marked observation ratio. The marker observation ratio is the ratio of the spectral reflectance of the marker in each wavelength region to the spectral reflectance of the surrounding area, wherein each wavelength region is one of multiple wavelength regions divided from the visible light wavelength region. The deviation of the marker observation ratio from 1 in the first wavelength region is greater than the deviation of the marker observation ratio from 1 in the second wavelength region.

14. A method for controlling a light source device, the light source device generating illumination light to illuminate an object being observed, characterized in that, The processor controls the emitted light intensity of the first and second light sources based on spectral setting information, such that the emitted light intensity of the first light source is greater than that of the second light source. The first light source emits light with a peak wavelength in a first wavelength region, and the second light source emits light with a peak wavelength in a second wavelength region. The observed object includes a region of interest, a marker, and a surrounding region. The marker is a component existing outside the region of interest but in a region related to the region where the region of interest is located. The surrounding region is a region outside the region of interest and does not contain the marker. The spectral setting information is set based on the marked observation ratio. The marker observation ratio is the ratio of the spectral reflectance of the marker in each wavelength region to the spectral reflectance of the surrounding area, wherein each wavelength region is one of multiple wavelength regions divided from the visible light wavelength region. The deviation of the marker observation ratio from 1 in the first wavelength region is greater than the deviation of the marker observation ratio from 1 in the second wavelength region.

Images