JP2021010404A - Observation device, observation method, and endoscope apparatus - Google Patents

Abstract

To provide an observation device, an observation method, and an endoscope apparatus, capable of diagnosing cancer infiltration in each layer by separating a surface layer part from a deep part of an object.SOLUTION: An observation device 100 includes a polarization detector 40 for detecting a polarization state of light from an object in each of a plurality of wavelengths, and a determination part 223a for determining the object state at a depth position corresponding to the wavelength, based on the polarization state. An observation method includes a stage for detecting the polarization state of light from the object in each of the plurality of wavelengths, and a stage for determining the object state at the depth position corresponding to the wavelength, based on the polarization state.SELECTED DRAWING: Figure 4

Description

The present invention relates to an observation device, an observation method and an endoscopic device.

Non-return light from a digestive organ, especially a tissue with structural anisotropy due to orientation, etc., that occurs in the mucosal layer of the stomach wall, with one light source of a given narrow band wavelength and polarized light. The thickness of the mucosal layer is calculated based on the ratio of polarized light, that is, the degree of polarization of return light. It is known that this may detect a change in the thickness of the mucosal layer of the stomach wall, thereby diagnosing the degree of cancer infiltration (see Patent Document 1).

Japanese Patent No. 5501155

However, with the technique disclosed in Patent Document 1 described above, it is difficult to separate the surface layer portion and the deep layer portion to diagnose the degree of cancer infiltration in each layer.

According to the first aspect, the observation device includes a polarization detection unit that detects the polarization state of light from the object for each of a plurality of wavelengths, and the object at a depth position corresponding to the wavelength based on the polarization state. It is provided with a determination unit for determining the state of. According to the second aspect, the observation method includes a step of detecting the polarization state of light from the object for each of a plurality of wavelengths and the state of the object at a depth position corresponding to the wavelength based on the polarization state. And the stage of determining.

It is a figure which shows the main part of the endoscope apparatus to which the observation apparatus which is an embodiment is applied. It is a block diagram which shows the schematic structure of the endoscope system to which the observation apparatus which is an embodiment is applied. It is a block diagram which shows the schematic structure of the parent endoscopy system which is an embodiment. It is a block diagram which shows the schematic structure of the child endoscopy system to which the observation device which is an embodiment is applied. It is a perspective view which shows the tip part of the insertion part of the parent endoscope apparatus and the child endoscope apparatus which are embodiment. FIG. 5 is a cross-sectional view taken along the line AA of FIG. It is sectional drawing which shows the main part of the observation apparatus which is an embodiment. It is a perspective view which shows the main part of the observation apparatus which is an embodiment. It is a perspective view which shows the main part of the observation apparatus which is an embodiment. It is a figure which shows the schematic structure of the tip part of the insertion part of the endoscope device which concerns on embodiment. It is a figure which shows the relationship of the polarization state of the light emitted from the polarization generation part in the observation apparatus which is an embodiment. It is a figure which shows the difference in arrival in the structure of the light having a short wavelength and the light which has a long wavelength, and the depth region used for the Jones matrix. It is a figure which shows the difference in arrival in the structure of the light having a short wavelength and the light having a long wavelength in the folding optical system in order to replace the folding optical system with a transmission optical system. It is a figure which shows the state which replaced the folding optical system with a transmission optical system for light having a short wavelength. It is a figure which shows the state which replaced the folding optical system with a transmission optical system for light having a long wavelength.

An endoscopic system to which the observation device of the embodiment is applied and a child endoscopic device will be described with reference to FIGS. 1 to 6. In these figures, the endoscope system 1 according to the present embodiment is a parent-child endoscope system, and is composed of a parent endoscope system 1A and a child endoscope system 1B. The parent endoscope system 1A includes a parent endoscope device 110 and a parent main body 210. The child endoscope system 1B has a child endoscope device 120 and a child side main body 220. The parent-child endoscope is a device in which a small-diameter endoscope, which is a child endoscope, is inserted into the working channel of a normal-sized endoscope, which is a parent endoscope.

As shown in FIG. 1, the parent endoscope device 110 inserts the tip 112 of the insertion portion 111 into the body cavity of a subject such as the human body, and irradiates an object such as the inner surface of the mucous membrane in the subject with light. .. The parent endoscope device 110 captures the return light from the object and acquires an image signal of the object image. In the child endoscope device 120 as well as the parent endoscope device 110, the tip portion 122 of the insertion portion 121 is inserted into the body cavity of the subject such as the human body, and light is emitted to an object such as the inner surface of the mucous membrane in the subject. Irradiate. The child endoscope device 120 captures the return light from the object and acquires an image signal of the object image.

The parent main body 210 has a light source 216 (see FIG. 3) that generates light emitted from the tip 112 of the parent endoscope device 110, and has a light source 216 (see FIG. 3) with respect to an image signal acquired by the parent endoscope device 110. Performs various image processing. Like the parent main body 210, the child main body 220 also has a light source 226 (see FIG. 4) that generates light emitted from the tip 122 of the child endoscope device 120, and is a child endoscope device. Various image processing is performed on the image signal acquired by 120.

The parent endoscope device 110 has an insertion unit 111, an operation unit 113, and a connector unit 114. The insertion portion 111 has a flexible (that is, soft) tube member 111a and has an elongated shape. The operation unit 113 operates the bending operation and the observation operation performed by the tip portion 112 of the insertion unit 111. The connector portion 114 detachably connects the parent endoscope device 110 to the parent side main body portion 210.

As shown in FIGS. 5 and 6, a working channel 116 is formed inside the insertion portion 111 of the parent endoscope device 110. The working channel 116 is a hollow tubular passage formed inside the insertion portion 111. The working channel 116 extends from the opening 113a formed in the operation portion 113 to the tip portion 112 of the insertion portion 111. The working channel 116 is generally used to guide a treatment tool such as forceps to the tip 112 of the parent endoscope device 110.

As shown in FIG. 1, the child endoscope device 120 has an insertion unit 121, an operation unit 123, and a connector unit 124, similarly to the parent endoscope device 110. The insertion portion 121 of the child endoscope device 120 is inserted into the working channel 116 of the parent endoscope device 110.

As shown in FIG. 3, the main body 210 includes a control unit 211, a storage unit 212, an image processing unit 213, a detection unit driver 214, a light source driver 215, a light source 216, and a condenser lens 217. , Have. Further, the parent main body 210 has a display controller 218 and an input interface (I / F) 219. The main body 210 is connected to the parent endoscope device 110 by an optical connector 310 and an electric connector 311.

The control unit 211 has an arithmetic element such as a CPU, and a control program (not shown) stored in the storage unit 212 is read out at startup and executed by the control unit 211. As a result, the control unit 211 controls the entire parent endoscope system 1A including the image processing unit 213, the detection unit driver 214, the light source driver 215, the display controller 218, and the input interface 219.

The storage unit 212 includes a large-capacity storage medium such as a hard disk drive and a semiconductor storage medium such as a ROM or RAM. The above-mentioned control program is stored in the storage unit 212, and various data required for the control operation of the control unit 211 are temporarily stored. Image data processed by the image processing unit 213 is stored in the storage unit 212.

The image processing unit 213 acquires an image signal of an object image captured by the detection unit 316 of the parent endoscope device 110, and performs various image processing on the image signal. The image processing unit 213 outputs the image processing result to the display controller 218.

The detection unit driver 214 generates a signal for driving the detection unit 316 to the detection unit 316 and supplies the signal to the detection unit 316.

The light source 216 generates light emitted from the tip 112 of the parent endoscope device 110, and is driven by the light source driver 215. The light source 216 according to the present embodiment generates illumination light that illuminates an object. For example, the light source 216 is a light emitting element that emits white light.

The light generated by the light source 216 is converged to a light flux having a constant width by the condenser lens 217, and is guided into the optical fiber 115 of the parent endoscope device 110 via the optical connector 310.

The display controller 218 generates a display drive signal for displaying an image signal output from the image processing unit 213 on the screen of the display 312 provided outside the main body 210 on the parent side, and displays this on the display 312. Supply.

The input interface 219 receives an operation input signal from an input device 330 such as a keyboard provided outside the main body 210 on the parent side, and supplies the operation input signal to the control unit 211.

As shown in FIG. 4, the child side main body 220 also includes the control unit 221 and the storage unit 222, the image processing unit 223, the detection unit driver 224, and the light source driver 225, similarly to the parent side main body 210. It has a light source 226 and a condenser lens 227. Further, the child side main body 220 has a display controller 228 and an input interface (I / F) 229. The child-side main body 220 is connected to the child endoscope device 120 by an optical connector 30 and an electric connector 31.

The control unit 221 has an arithmetic element such as a CPU, and a control program (not shown) stored in the storage unit 222 is read out at startup and executed by the control unit 221. As a result, the control unit 221 controls the entire child endoscope system 1B including the image processing unit 223, the detection unit driver 224, the light source driver 225, the display controller 228, and the input interface (I / F) 229. ..

The storage unit 222 includes a large-capacity storage medium such as a hard disk drive and a semiconductor storage medium such as ROM and RAM. The above-mentioned control program is stored in the storage unit 222, and various data required for the control operation of the control unit 221 are temporarily stored. Image data processed by the image processing unit 223 is stored in the storage unit 222.

The image processing unit 223 acquires an image signal of an object image captured by the detection unit 50 of the child endoscope device 120, and performs various image processing on the image signal. The image processing unit 223 outputs the image processing result to the display controller 228.

The image processing unit 223 of the child side main body 220 has a determination unit 223a. The determination unit 223a determines the state of the object at the depth position corresponding to the wavelength based on the polarization state of the light of two wavelengths from the object based on the image signal of the object image captured by the detection unit 50. To do.

The details of the image processing performed by the detection unit 50 and the image processing unit 223 of the child side main body 220 will be described later.

The detection unit driver 224 generates a signal for driving the detection unit 50 with respect to the detection unit 50 and supplies the signal to the detection unit 50.

The light source 226 generates light emitted from the tip portion 122 of the child endoscope device 120, and is driven by the light source driver 225. The light source 226 according to the present embodiment has a short wavelength light source 226a and a long wavelength light source 226b. The short wavelength light source 226a and the long wavelength light source 226b have a narrow band and low spatial coherence, and generate light with speckle removed or reduced. The short wavelength light source 226a and the long wavelength light source 226b are provided with a speckle removal mechanism or a reduction mechanism for removing or reducing speckle. The light source driver 225 drives the short wavelength light source 226a and the long wavelength light source 226b alternately or simultaneously.

The wavelength band of the light generated by the short wavelength light source 226a is set shorter than the wavelength of the long wavelength light source 226b, and for example, one wavelength or a plurality of wavelengths may be selected between 400 nm and 450 nm.

The wavelength band of the light generated by the long wavelength light source 226b is set longer than the wavelength of the short wavelength light source 226a, and for example, one wavelength or a plurality of wavelengths may be selected between 600 nm and 650 nm.

The bandwidth of the light generated by the short wavelength light source 226a and the long wavelength light source 226b is 5 nm or less, preferably about 3 nm. In terms of bandwidth, such a short wavelength light source 226a and a long wavelength light source 226b are preferably composed of a laser light source. The wavelength band of the short wavelength light source 226a and the long wavelength light source 226b is preferably selected from a wavelength between 405 nm and 670 nm.

The wavelength band and bandwidth of the light generated by the short-wavelength light source 226a and the long-wavelength light source 226b can be determined by the number and width of interference fringes generated on the image sensor 57 of the detection unit 50, which will be described later.

The condenser lens 227 includes a short wavelength condenser lens 227a and a long wavelength condenser lens 227b. The light generated by the short wavelength light source 226a is converged to a constant width light beam by the short wavelength condensing lens 227a, and the light generated by the long wavelength light source 226b is converged to a constant width light beam by the long wavelength condensing lens 227b. Then, the light is guided into the optical fiber 15 of the child endoscope device 120 via the optical connector 30.

Here, the number of optical fibers 15 is equal to the number of polarization generating units 60 of the polarization detecting unit 40, which will be described later. In the present embodiment, the number of the polarization generating units 60 is 6, so the number of the optical fibers 15 is 6. Therefore, a switching unit 226c is provided between the light source 226 and the condenser lens 227. The switching unit 226c guides the light of either the short wavelength light source 226a or the long wavelength light source 226b lit by the light source driver 225 into any one optical fiber 15. When the short wavelength light source 226a and the long wavelength light source 226b are driven at the same time, the switching unit 226c shuts off either of them by the shutter. At the same time, when the short wavelength light source 226a and the long wavelength light source 226b are driven alternately or simultaneously, the switching unit 226c transmits light to the optical fibers 15 other than the optical fiber 15 that guides the light among the six optical fibers 15. Cut off. The irradiation of the short wavelength light source 226a and the long wavelength light source 226b may be switched in order for each optical fiber 15, or the optical fibers 15 for incident light may be sequentially switched for each of the short wavelength light source 226a and the long wavelength light source 226b. You may switch.

The display controller 228 generates a display drive signal for displaying an image signal output from the image processing unit 223 on the screen of the display 32 provided outside the child side main body 220, and displays this on the display 32. Supply.

The input interface 229 receives an operation input signal from an input device 330 such as a keyboard provided outside the child side main body 220, and supplies the operation input signal to the control unit 221.

The polarization detection unit 40 of the observation device 100 according to the present embodiment is provided at the tip end portion 122 of the insertion portion 121 of the child endoscope device 120, as shown in FIGS. 4, 5 to 7, and 10. There is.

Hereinafter, the tip portions 112 and 122 will be described with reference to FIGS. 5 and 6.

An illumination light detection unit 314 is provided at the tip end 112 of the parent endoscope device 110. The illumination light detection unit 314 has an illumination unit 315, a detection unit 316, and a nozzle 317. The illumination unit 315 irradiates the object with the light of the light source 216. The detection unit 316 detects the light from the object irradiated with the light by the illumination unit 315. The nozzle 317 injects water or the like onto the object. The opening 116a of the working channel 116 described above is formed at the tip 112 of the parent endoscope device 110.

The polarization detection unit 40 is provided at the tip portion 122 of the child endoscope device 120, and is arranged at the tip portion 112 of the parent endoscope device 110 in a state where the insertion portion 121 is inserted into the working channel 116. There is. In FIG. 5, in order to clearly show the arrangement state of the polarization detection unit 40, the polarization detection unit 40 is shown so as to project outward from the opening 116a of the working channel 116. However, when observing the object by the polarization detection unit 40, the polarization detection unit 40 is housed in the working channel 116 as shown in FIG.

Hereinafter, the polarization detection unit 40 will be described with reference to FIGS. 7 to 11. In the following description, mainly the optical element and the optical path will be described. In FIGS. 7 to 11, the electric circuit connecting the detection unit 50 and the child-side main body 220, the coating of the child endoscope device 120, etc. Detailed description of other configurations will be omitted.

The polarization detection unit 40 is a detection unit 50 that detects light from an object, and six polarization generation units that are arranged around the detection unit 50 to generate light having different polarization states and irradiate the object. Has 60 and. As shown in FIGS. 7 and 10, the detection unit 50 and the polarization generation unit 60 are housed in the tube member 121a of the insertion unit 121 of the child endoscope device 120.

As shown in FIGS. 7 and 7 onward, the x-axis is taken in the optical axis direction of the detection unit 50. Then, the positive direction of the x-axis is set as the direction toward the object.

As shown in FIG. 7, the detection unit 50 includes a front group lens 51, an aperture 52, a polarization separation unit 53, an imaging lens 54, a polarizing plate 55, a protective glass 56, and an image sensor 57.

The front group lens 51 is arranged on the object side (right end in FIG. 7) in the detection unit 50. The diaphragm 52 is formed in an annular shape and is arranged on the exit side of the front group lens 51. The light emitted from the diaphragm 52 is incident on the polarization separation unit 53. The imaging lens 54 is a rear lens group that forms an image of interference fringes of light emitted from the polarizing separation unit 53 on the imaging surface 57a of the image sensor 57, which will be described later. The polarizing plate 55 and the protective glass 56, which are detectors, are arranged in order in front of the imaging surface 57a of the image sensor 57 (on the right side in FIG. 10). The image sensor 57 is an image pickup device having a plurality of pixels, and images interference fringes formed on the image pickup surface 57a.

The detection unit 50 is designed so that at least a part of the common portion of the illumination range of the object by the six polarization generation units 60, which will be described in detail later, is the detection range, and more preferably, the six polarization generation units. The imaging range is set to be wider than the total illumination range of 60. Alternatively, depending on the detection range of the detection unit 50, the polarization generation unit 60 may be designed so that this detection range is at least a part of the common portion of the illumination range of the object by the polarization generation unit 60.

The emission angles of the plurality of polarized light generating units 60 may be set so that the generated polarized light is irradiated to the detection range of the detection unit 50. In this case, the arrangement state of each of the plurality of polarization generating units 60 may be adjusted. By setting the illumination range of the object by the polarization generating unit 60 and the detection range of the detection unit 50 in this way, the return light from the irradiation range of the object can be reliably detected by the detection unit 50. In this embodiment, the irradiation optical axis of the polarized light to be irradiated and the optical axis of the light received from the irradiation region received by the detection unit 50 are for reducing the specular reflection light from the irradiation region of the polarized light to be irradiated. May be offset from each other.

The polarization separating unit 53 has two modified Sabar plates 53c and a 1/2 wavelength plate 53d arranged between the modified Sabar plates 53c. The modified Sabar plate 53c in the present embodiment is formed by two parallel flat plates 53a (for example, YVO4) made of birefringent uniaxial crystals and 1/2 of a wide band arranged between the parallel flat plates 53a. It has a wave plate 53b.

The modified Sabar plate 53c is formed by laminating a pair of parallel flat plates 53a having birefringence so that their optical axes differ by 90 ° via a 1/2 wavelength plate 53d arranged in a specific crystal orientation. Is. When the light incident on the modified Sabar plate 53c is light in which different polarized states are overlapped, the modified Sabar plate 53c separates and emits light having different polarized states.

The light emitted from the polarization separation unit 53 is converged by the imaging lens 54, and is imaged on the imaging surface 57a of the image sensor 57 through the polarizing plate 55 and the protective glass 56. Then, light in different polarized states interferes on the imaging surface 57a to form interference fringes.

The image sensor 57 images the light formed on the image pickup surface 57a and outputs the result as an image signal. Since the image sensor 57 images the interference fringes formed on the image pickup surface 57a as described above, the image sensor 57 has a resolution capable of capturing fine interference fringes. The number and width of the interference fringes formed on the imaging surface 57a depend on the wavelength band of the light generated by either the short wavelength light source 226a or the long wavelength light source 226b.

As shown in FIGS. 8 and 9, each of the plurality of polarization generating units 60 includes one polarizing plate (polarizing conversion element) 61a to 61f and a plano-concave lens (planar concave lens) arranged on the exit side of the polarizing plates 61a to 61f, respectively. It has a divergent optical element) 62. Further, a quarter wave plate (polarizing optical element) 63 is arranged between some of the polarizing plates 61a and 61b and the plano-concave lens 62. When the 1/4 wave plate 63 is arranged, the polarization generating unit 60 is composed of one polarizing plate 61a, 61b, the 1/4 wave plate 63, and the plano-concave lens 62. In the following description and illustration, when the positions of the polarizing plates 61a to 61f are generally shown without being specified, they will be described as represented by reference numerals 61.

As shown in FIGS. 8 and 9, the six polarization generating units 60 are divided into two groups and arranged around the detecting unit 50. More specifically, the three polarization generating units 60 are arranged in the upper part of the drawing of the polarization separating unit 53, and the three polarization generating units 60 are arranged in the lower part of the drawing of the polarization separating unit 53. Further, the six polarization generating units 60 are arranged in the same plane orthogonal to the x-axis which is the optical axis direction of the detecting unit 50.

As shown in FIGS. 8 and 9, when viewed along the x-axis, a part of each of the plurality of polarization generating units 60 overlaps with a part of the image sensor 57. As a result, the outer diameter of the polarization detection unit 40 of the present embodiment as viewed from the optical axis direction of the detection unit 50 can be made more compact. As a result, it is possible to contribute to the miniaturization of the entire polarization detection unit 40. At least a part of at least one of the plurality of polarization generating units 60 may be arranged so as to overlap the image sensor 57 in the optical axis direction of the detecting unit 50.

The six polarization generating units 60 irradiate the object with light having different polarization states for each wavelength. This point will be described in detail below.

The polarization state of light can be described by a Stokes vector, and this Stokes vector can be written by a Stokes matrix of 4 rows and 1 column as shown in the following equation.

Here, as for each component of the Stokes matrix, s ₀ is light intensity, s ₁ is xy linearly polarized light, s ₂ is 45 ° linearly polarized light, and s ₃ is circularly polarized light. s ₀ takes a positive value to represent the intensity. s ₁ = s ₀ means 0 ° linearly polarized light, and s ₁ = −s ₀ means 90 ° linearly polarized light. Further, s ₂ = s ₀ means that it is linearly polarized at 45 °, and s ₂ = −s ₀ means that it is linearly polarized at −45 °. Further, s ₃ = s ₀ means that it is clockwise circularly polarized light, and s ₃ = −s ₀ means that it is counterclockwise circularly polarized light.

Each combination of the polarization generating unit 60, more specifically, the polarizing plates 61a to 61f and the 1/4 wave plate 63 has 6 types of s ₁ = ± 1, s ₂ = ± 1, and s ₃ = ± 1. It is set to generate light having a polarized state of any one of the polarized states.

Specifically, in the six polarization generating units 60, as shown in FIG. 11, the polarizing plates 61a to 61f are arranged so that the Stokes component of the light emitted from each polarization generating unit 60 is a component shown in the drawing. It is selected and the arrangement position of the 1/4 wave plate 63 is determined.

It is possible to arbitrarily determine how to make the polarization state of the light emitted from each polarization generating unit 60 different, in other words, what kind of Stokes component the light has.

Here, since the change in the polarization state of the Stokes component s ₁ with an angle is smaller than that of the other components s ₂ and s ₃ , the polarizing plate 61c and the Stokes component s ₁ = − that irradiate light having the Stokes component s ₁ = + 1. There is no problem even if the polarizing plate 61f for irradiating the light having 1 is arranged apart.

In addition, with respect to the polarizing plates 61a and 61b and the 1/4 wave plate 63 that irradiate light having the Stokes component s ₃ = ± 1, the 1/4 wave plate 63 arranged on the emitting side of these polarizing plates 61a and 61b There is a merit that these polarizing plates 61a and 61b are arranged side by side from the viewpoint that the holders shown in the drawing for holding the 1/4 wave plate 63 can be shared.

The plano-concave lens 62 is a lens that radiates the light emitted from the polarizing plate 61 and the quarter wave plate 63 to illuminate the object. Here, the optical design of the plano-concave lens 62 is made so that the half angle of view of the light emitted from the plano-concave lens 62 is within 35 degrees. This is because if the half angle of view is within 35 degrees, the polarization state of the light emitted from the polarization generating unit 60 does not change significantly. Further, considering the numerical aperture (NA) of the optical fiber 15 described in detail later, the half angle of view of the light emitted from the optical fiber 15 is within 15 degrees.

The plano-concave lens 62 as a divergent optical element used in the polarization generating unit 60 has better polarization performance as compared with other optical elements having a light diverging effect, for example, a ball lens. Suitable.

Light is guided to the polarization generating unit 60 by the optical fiber 15 of the child endoscope device 120, as shown in detail in FIGS. 7 and 10. As shown in FIG. 7, the optical fiber 15 extends in the tube member 121a of the insertion portion 121 of the child endoscope device 120 along the longitudinal direction of the insertion portion 121, and reaches the tip portion 122 of the insertion portion 121. The exit end 15a is arranged near the incident end (left end in FIG. 7) of the polarizing plate 61.

The optical fiber 15 eliminates the polarization state of the light from the short wavelength light source 226a or the long wavelength light source 226b (polarization scramble) and guides the light to the polarization generation unit 60. In the present embodiment, as shown in FIG. 10, the optical fiber 15 is a multimode optical fiber in which the cross section of the core 15b is substantially square and the cross section of the clad 15c is substantially circular. The optical fiber 15 having such a configuration can supply stable depolarized light to the incident surface of the polarizing plate 61, and therefore the polarized state passing through the polarizing plate 61 maintains stable light intensity spatially and temporally. be able to.

In the present embodiment, the child endoscope device 120 is provided with the same number of optical fibers 15 as the polarization generating unit 60, that is, six optical fibers 15 (only two are shown in FIG. 7), and these optical fibers 15 are provided. Light is commonly guided from the short wavelength light source 226a or the long wavelength light source 226b. Therefore, the polarization generating unit 60 irradiates the object with light having different polarization states in a time-division manner.

Each element constituting the polarization detection unit 40 according to the present embodiment is made of a material capable of maintaining high polarization measurement accuracy even when sterilized in a high temperature environment. Specifically, the 1/2 wave plates 53b and 53d and the 1/4 wave plate 63 are made of quartz. Further, the plano-concave lens 62 is made of optical glass. Further, the polarizing plate 61 is made of an inorganic material or a wire grid. The parallel flat plate 53a constituting the modified Sabar plate 53c is composed of YVO ₄ .

Here, the sterilization autoclave is carried out, for example, under any of the conditions of 115 ° C. for 30 minutes, 121 ° C. for 20 minutes, 126 ° C. for 15 minutes, and 134 ° C. for 10 minutes.

The observation device 100 according to the present embodiment is composed of a polarization detection unit 40 and an image processing unit 223, particularly a determination unit 223a.

Next, the principle of the measurement method of the Stokes components s _{0 to} s ₃ by the endoscope system 1 using the polarization detection unit 40 will be described (K. Oka and N. Saito, "Snapshot complete imaging polarimeter using Savart plates", See SPIE 6295-9, 1 (2006), N. Saito, S. Odate, K. Otaki, M. Kubota, R. Kitahara, and K. Oka, "Wide field snapshot imaging polarimeter using modified Savart plates", SPIE 88730M -1 (see 2013)).

Let I (x, y) be the intensity distribution of the light imaged by the image sensor 57. Assuming that the two-dimensional distributions of the Stokes components contained in the measurement light are s ₀ (x, y), s ₁ (x, y), s ₂ (x, y), and s ₃ (x, y), respectively, these Stokes components The light intensity distribution can be expressed using the two-dimensional distribution of.

Here, arg is a function indicating the argument of a complex number, and φ ₁ (x, y) and φ ₂ (x, y) are phase differences given by two modified Sabar plates 53c, respectively.

In the above equation, s ₀ (x, y), s ₁ (x, y) and s ₂₃ (x, y) have four different phases (especially the real and imaginary components for s ₂₃ (x, y)). It is modulated by the interference fringes and is included in one light intensity distribution I (x, y). That is, the obtained two-dimensional image having the light intensity distribution I (x, y) includes four interference fringes having different phases. By performing a two-dimensional Fourier transform on the light intensity distribution I (x, y) and performing spatial frequency filtering, the Stokes components separated on the frequency space can be individually extracted. The two-dimensional distribution of these Stokes components can be obtained from the amplitude and phase of the extracted components. At this time, the spatial frequency filtering and the modulation of the amplitude and the phase can be performed at once by the Fourier transform technique suitable for the modulation of the two-dimensional distribution of the Stokes component.

Therefore, the image processing unit 223 (including the determination unit 223a) of the child endoscope system 1B acquires the two-dimensional distribution of the intensity of the image signal output from the detection unit 50, and Fourier transforms the two-dimensional distribution of this intensity. As a result, the polarization state of the return light from the object, specifically, the two-dimensional distribution of the Stokes components s _{0 to} s ₃ is obtained.

Then, the determination unit 223a of the image processing unit 223 obtains the polarization characteristics of the object by using the two-dimensional distribution of the Stokes components s _{0 to} s ₃ . By comparing this polarization characteristic with a value that serves as a criterion for determining the degree of infiltration of the lesion, the determination unit 223a may estimate the degree of infiltration of the lesion. Further, by preparing in advance a database showing the relationship between the thickness of the mucosal layer of the object and the polarization characteristic (depolarization characteristic), the determination unit 223a can determine the mucosal layer of the object based on the obtained polarization characteristic. The thickness may be calculated to diagnose the degree of cancer invasion.

Stokes matrix of the incident light to the object and _{S = (s 0, s 1} , s 2, s 3), the return light Stokes matrix from the object _{S '= (s' 0,} s' 1, If _{s '2,} s' ₃₎ to the relationship of these Stokes matrix is represented by the Mueller matrix M of four rows and four columns indicating the polarization characteristics of the object. That is,

Here, it is difficult to make a strict correspondence between each element of all 16 elements m _{00 to} m ₃₃ of the Muller matrix M and the physical characteristics of polarized light, but as a rough relationship, the element m ₀₀ represents brightness, and all 16 elements. Elements m _{00 to} m ₃₃ represent the degree of polarization, elements m ₀₁ , m ₀₂ , m ₁₀ and m ₂₀ represent birefringence (straight birefringence), and elements m ₀₃ and m ₃₀ represent circular dichroism (circle). (Double absorption), elements m ₁₁ , m ₁₂ , m ₂₁ and m ₂₂ represent optical rotation (circular dichroism), and elements m _{11 to} m ₁₃ , m _{21 to} m ₂₃ and m _{31 to} m ₃₃ are birefringence. It represents sex (linear birefringence).

As described above, according to the polarization detection unit 40 of the present embodiment, Stokes having six types of light having different polarization states, in other words, Stokes components having different Stokes components (all of these Stokes components are known). Light represented by a matrix (referred to as S _{1 to} S ₆ ) is incident on an object, and the Stokes component of the return light from the object obtained by reflecting each light can be detected (this). Stokes matrix of Stokes component placing and _{S '1} ~S' _6). Since the Muller matrix M of the object is the same, each component of the Muller matrix M can be obtained from these Stokes matrices S _{1 to} S ₆ and S ′ _{1 to} S ′ ₆ .

That is, when four of the six polarization generating units 60 are used in the polarization detecting unit 40 of the present embodiment, each component of the Muller matrix M is uniquely determined by solving the four determinants. Further, if all six polarization generating units 60 are used, each component of the Muller matrix M can be obtained by using the least squares method.

Since two-dimensional distribution of the Stokes component of the Stokes matrix _S of the return light _{'= (s' 0, s} ' 1, s' 2, s' 3) is known, for each component of the Mueller matrix M of the object A two-dimensional distribution can also be obtained. This makes it possible to obtain a two-dimensional distribution of the degree of polarization of the object. The two-dimensional distribution of the thickness of the mucosal layer of the object may be calculated based on the two-dimensional distribution of the degree of polarization, thereby diagnosing the degree of cancer infiltration, which is one of the states of the object. ..

Next, the features of the present embodiment will be described. In the observation device 100 of the present embodiment, the surface layer portion and the deep layer portion in a predetermined region of the object are separated, and the degree of cancer infiltration in each layer is determined by the determination unit 223a. Hereinafter, this detection principle will be described. It should be noted that the predetermined region of the object is irradiated with light having a short wavelength λ _S (light having a first wavelength) and light having a long wavelength λ _L (light having a second wavelength), respectively. If the amount of displacement of the position of the irradiation region irradiated with light is larger than the optical resolution, it can be regarded as the same irradiation region. Further, if the amount of displacement of the position of the region through which the light having a short wavelength λ _S and the light having a long wavelength λ _L are transmitted inside the object is larger than the resolution, each light is inside the object. Can be regarded as transparent in the same area.

When one light source having a relatively long narrow band wavelength is provided, the light generated by the light source reaches the deep layer portion in addition to the surface layer portion of a predetermined region of the object. In this case, the calculated 16-element values of the Muller matrix M include the results of both the surface layer and the deep layer. However, it is difficult to separate the values of the 16 elements of the Muller matrix M in the surface layer portion and the deep layer portion only by the values of the 16 elements of the Muller matrix M with only one narrow band wavelength. For example, when the surface layer is normal tissue but the cancer tissue is present only in the deep layer, it is difficult to distinguish the cancer tissue only in the deep layer.

Therefore, in order to separate the values of the 16 elements of the Muller matrix M in the surface layer portion and the deep layer portion, the inventors, the light incident on the light scatterer reaches the deep part of the predetermined region of the object as the wavelength becomes longer. I focused on doing. That is, the inventors have come to the finding that it is possible to separate the values of 16 elements of the Muller matrix M in the surface layer portion and the deep layer portion by a plurality of wavelengths.

More specifically, the same predetermined region of the object is irradiated with polarized light from at least four, preferably six polarization generating units 60 for each of a plurality of wavelengths (two wavelengths in the present embodiment). The image sensor 57 receives light from the depth region of the irradiation region. The determination unit 223a calculates the Muller matrix M for each wavelength using the image of the image sensor 57. As a result, the M-matrix matrix M is acquired by the number of pixels that receive the light from the depth region of the irradiation region of the object. The determination unit 223a considers each of the 16 elements of the acquired Muller matrix M as 16th-order data. As a result, the same number of 16th-order data as the number of pixels that received light can be obtained. In the same pixel for each wavelength, the Mueller matrix M _D of the deep layer characterized by light having a light and long wavelength lambda _L with short wavelength lambda _S is obtained by the following equation in approximately.

Here, "M _S" is the Mueller matrix is measured with light having a light i.e. shorter wavelength lambda _S short wavelength light source 226a is generated, "M _L" light i.e. longer wavelength lambda generated long wavelength light source 226b It is a Muller matrix measured by light having _L.

Hereinafter, the principle of the present invention will be described in view of theoretical accuracy by using the Jones matrix J showing the polarization characteristics of the object, and then, in actual measurement conditions, the Muller matrix will be used instead of the Jones matrix J. Explain that is possible. When a plurality of polarization characteristics are combined, it can be represented by the Jones matrix J by the N matrix.

First, as shown in FIG. 12, generally, the longer the wavelength of the light incident on the light scattering body (the arrow F in FIG. 12), the deeper the light reaches the deep layer. Light with a short wavelength λ _S (arrow E) reaches tissue depth Z ₁ while light with a long wavelength λ _L (arrow F) reaches tissue depth Z ₂ . Then, the Jones matrix J of backscattered light is defined as shown in FIG. That is, as shown by the arrow E in FIG. 12, (J _{0, Z 1} ) is the Jones matrix J of the sum of the light that invades from the depth zero (tissue surface), reaches the depth Z ₁ and returns. To do. Each depth region (0, Z ₁ ), (Z ₁ , Z ₂ ) allows light absorption to be ignored, so the Jones matrix J is represented as a Shifter, Rotator, and a linear combination thereof. The thickness of the tissue layer represented by the depth from zero to the depth Z ₂ is approximately several mm or less. Note that (0, Z ₁ ) is the depth region (arrow E) of the surface layer portion from the depth zero to the depth Z ₁ , and (Z ₁ , Z ₂ ) is the depth Z ₁ to the depth Z ₂ The depth region (arrow G) of only the deep part up to is shown.

The Jones matrix J is formally represented by the following integral form. Here, "N" is the N matrix of the Jones matrix J.

The Jones matrix J in the depth region (0, Z ₁ ) of light having a short wavelength λ _S (eg, blue light) is expressed as follows.

Here, ρ (Z') is a probability weighting function of the approach path.

Similarly, the Jones matrix J in the depth region (0, Z ₂ ) of light having a long wavelength λ _L (eg, red light) is formally expressed as follows.

Here, the integral of _{J0 and Z2} is rewritten as follows.

Here, J _{Z1 and Z2} are defined as follows.

After all, the formula "Equation 9" is expressed as follows.

Further simplifying the notation as follows, the expression "several tens" and below becomes as follows.

Then, when the above condition, that is, the Jones matrix J is expressed as Shifter, Rotator, and a linear combination thereof, the Muller matrix M is calculated by the following equation. In this embodiment, the Jones matrix J can be converted to the Muller matrix M because the system does not have depolarization.

Substituting the "number 11" formula into the "number 12" formula

Here, it is assumed that the observed thickness of the tissue layer is several mm or less, and the N matrix in each depth region can be approximated by an average value. That is, the following equation is assumed.

Here, δ ₁ and δ ₂ are the effective optical lengths in each depth region (secondary minute amount).

By transforming the "Equation 13" equation using the "Equation 14" equation, the following equation can be obtained.

As a result, in the previous discussion, replaced with the "number 15" type of "M" and "M _L" replace "M _1" and "M _S", replacing the "M _2" and "M _D" Therefore, the above "Equation 4" formula was obtained.

Hereinafter, based on FIGS. 13 to 15, the “Equation 4” equation will be described by replacing the folded optical system with a transmission optical system.

As shown in FIG. 13, light having a short wavelength λ _S (for example, blue light) and light having a long wavelength λ _L (for example, red light) reach the surface layer portion from a depth of zero to a depth of Z _1. it can. Light having a long wavelength λ _L can reach deep layers from depth Z ₁ to depth Z ₂ . In this way, the light that has entered the object has different layers that can be reached depending on the length of the wavelength. Then, FIG. 13 is replaced with a transmission optical system as shown in FIGS. 14 and 15.

Light having a shorter wavelength lambda _S reaches the depth Z ₁ from zero depth, the flow returns to depth zero depth from Z _1. In other words, light with a short wavelength λ _S passes through the surface layer twice. Therefore, the light having a short wavelength λ _S is replaced in the transmission optical system as shown in FIG. The relationship of the Stokes matrix in FIG. 14 is represented by the Muller matrix M of 4 rows and 4 columns. That is,

Here, "S _in " is an input (illumination) Stokes spectrum, "S _out " is an output (detection) Stokes vector, and "M ₁ " is a Muller matrix when light is transmitted once through the surface layer. is there.

On the other hand, light having a longer wavelength lambda _L reaches the depth from zero to a depth Z _2, returns to the depth zero depth from Z _2. In other words, light having a long wavelength λ _L passes through the surface layer portion and the deep layer portion twice, respectively. Therefore, the light having a long wavelength λ _L is replaced in the transmission optical system as shown in FIG. The relationship of the Stokes matrix in FIG. 15 is represented by the Muller matrix M of 4 rows and 4 columns. That is,

Here, "M ₂ " is a Muller matrix when light is transmitted once through the deep layer portion.

Then, the Muller matrices M ₁ and M ₂ of the structure use a model approximated as a depolarizing element. In other words, the values (diagonal components) of the diagonal matrix elements of the Muller matrices M ₁ and M ₂ are approximated. In the following equation, the absolute value of the value (diagonal component) of the off-diagonal matrix elements of the Muller matrices M ₁ and M ₂ is smaller than the predetermined value, or the value of the diagonal matrix element (at least one). The approximation holds when the ratio or difference between and the value of the off-diagonal matrix element is greater than the predetermined value. That is,


If neither of these applies and the approximation does not hold, the approximation method is not used and "Equation 4" is used. Further, the determination unit 223a determines whether or not the approximation holds, and also determines whether or not to use "Equation 4".

By transforming "M ₁ M ₁ " of the "Equation 16" equation using the "Equation 18" equation, the following equation can be obtained.

By transforming "M ₁ M ₂ M ₂ M ₁ " of the "Equation 17" equation using the "Equation 18" equation and the "Equation 19" equation, the following equation can be obtained.

Therefore, the action of the surface layer portion can be obtained from the result of the equation "Equation 16". Further, since the Muller matrices M ₁ and M ₂ are similar to diagonal matrices, the inverse matrix of the "Equation 20" equation can be used for the "Equation 21" equation. Therefore, the action of the deep layer can be obtained from the results of the "Equation 17" and "Equation 16" equations. That is, if the inverse matrix of the Muller matrix M _S of light having a short wavelength λ _{S is used} for the Muller matrix M _{L of} light having a long wavelength λ _L , the Muller matrix M of the deep layer portion is used as in the above “Equation 4” equation. _D is found. Therefore, it is possible to obtain the action of the deep layer portion by the transmission optical system as in the above-mentioned "Equation 4" equation.

Next, the effectiveness of the "Equation 4" equation is confirmed from the values of the diagonal matrix elements of the Muller matrix by the transmission optical system from the experimental results of measuring the human large intestine tissue.

The experimental results of the measured average values (all patients) for each wavelength in human large intestine tissue will be described. Using experimental results from the "number 16" formula of the - "number 21" type, non-cancerous tissue (normal tissue) and Mueller matrix obtained by the surface layer portion per each cancer tissue (M 1 ^₂₎ deep obtained Mueller matrix in part sought diagonal elements of (M ₂ ^2). Then, the non-cancerous tissue and the cancerous tissue were compared based on the diagonal components. From the ratio of the same diagonal components of the Muller matrix (M ₁ ² ) obtained in the surface layer of the non-cancer tissue and the Muller matrix (M ₂ ² ) obtained in the deep layer, the surface layer of the cancer tissue The ratio of the same diagonal components of the Muller matrix (M ₁ ² ) obtained in 1 and the Muller matrix (M ₂ ² ) obtained in the deep part is larger by about 70 to about 80%. It became clear from the experimental results. In other words, in the cancer tissue, towards the diagonal components of the resulting Mueller matrix (M 1 ^₂₎ Mueller matrix obtained by the deep portion than diagonal elements (M 2 ^₂₎ element surface part is smaller The experimental results revealed that there was a tendency.

Further, even in the experimental results for each patient for each wavelength in human colon tissue, like the measured average value, each of the surface layer portion obtained in Mueller matrix of the non-cancerous tissue and cancerous tissue for each patient (M ₁ ² ) And the diagonal components of the Muller matrix (M ₂ ² ) obtained in the deep part were obtained. Then, when compared with the measured average value, it was clarified from the experimental results that the cancer tissue can be detected in about 75 to about 85%.

Therefore, the cancer tissue in the deep layer can be determined from the value of the diagonal matrix element of the Muller matrix M by the transmission optical system. Therefore, the inventors have come to the finding that the "Equation 4" equation is effective from the values of the diagonal matrix elements of the Muller matrix M by the transmission optical system.

The observation device 100 according to the present embodiment configured as described above includes a polarization detection unit 40 that detects the polarization state of light from an object for each of two wavelengths, and a polarization characteristic calculated based on the polarization state. It has a determination unit 223a for determining the state of the object at the depth position corresponding to the wavelength by the ratio of the values indicating.

Therefore, by using the determination result of the determination unit 223a, the surface layer portion and the deep layer portion of the same predetermined region can be separated to diagnose the degree of cancer infiltration in each layer.

Further, according to the observation device 100 of the present embodiment, it is possible to observe the polarized state of the object without using a complicated mechanism. Further, in the observation device 100 of the present embodiment, the size of the entire device can be reduced.

Although the embodiment has been described in detail with reference to the drawings, the specific configuration is not limited to the embodiment and the embodiment, and design changes to the extent that the gist of the embodiment is not deviated are described in the present disclosure. included.

As an example, the child-side main body 220 of the child endoscope system 1B according to the above-described embodiment is provided with a short-wavelength light source 226a and a long-wavelength light source 226b, but three or more light sources may be provided. In this case, the wavelength bands of light generated by each light source are different.

Further, instead of the short wavelength light source 226a and the long wavelength light source 226b, one light source (for example, an LED light source) containing a plurality of wavelength components may be provided. In this case, a narrow band light may be generated by dispersing the light generated by one light source using a spectroscope, or a band pass filter may be added to generate a narrow band light. On the other hand, the light generated by one light source is incident on the optical fiber 15 without adding the bandpass filter, and the light from the irradiation region is passed through the bandpass filter provided at least in front of the image sensor 57, resulting in a narrow band. The light may be received by the image sensor 57. Further, when the short wavelength light source 226a and the long wavelength light source 226b are driven at the same time, the light generated by each may be incident on the optical fiber 15 without using the shutter, and similarly, at least in front of the image sensor 57. A bandpass filter may be provided, and either narrow-band light may be received by the image sensor 57. However, when a bandpass filter is used, it is necessary to provide at least two or more bandpass filters that can be switched, and it is necessary to transmit different narrow band light. Further, when the bandpass filter is provided at least in front of the image sensor 57, it is necessary to consider that a predetermined narrow band is cut by the polarizing optical element provided between the optical fiber 15 and the image sensor 57.

In addition, the diagnosis of cancer infiltration is not limited to the above-described embodiment. For example, the thickness and depth position of the lesion in the object can be specified by performing the following measurements. Specifically, on the same organ to be diagnosed, information that shows the relationship between the depth measured at a clearly normal place and the change in the Muller matrix is acquired in advance. Next, as in the above embodiment, the same predetermined region suspected of having a lesion is irradiated with two lights having different wavelengths. As a result, information on the Muller matrix obtained in the surface layer portion from the depth zero to the depth Z ₁ and the Muller matrix obtained in the deep layer portion from the depth Z ₁ to the depth Z ₂ can be obtained. Next, from the information acquired in advance and their Muller matrix, it is determined that there is a lesion in the deep part from the depth Z ₁ to the depth Z ₂ , for example. However, at this point, the extent of the lesion in the deep part is unknown. Next, in order to clarify the existence range, the highest point of the existence range of the lesion is obtained by fixing the light having a long wavelength λ _L and gradually increasing the wavelength of the light having a short wavelength λ _S. Can be measured. At this time, both of the two lights are applied to the lesion portion. As a result, the thickness of the lesion is calculated from the difference between the arrival points of the two lights. Further, if the lowest point of the existence range of the lesion is clarified by fixing the light having a short wavelength λ _S and gradually shortening the wavelength of the light having a long wavelength λ _L , the thickness of the lesion can be clarified. It is possible to measure the wavelength more accurately.

Further, in the above-described embodiment, the same predetermined region of the object is irradiated with polarized light from the polarization generating unit 60 for each of the light sources 226a and 226b, and the light from the depth region of the irradiation region is received by the image sensor 57. An example is shown. However, a predetermined region is divided into a plurality of small regions in a matrix, for example, and scanning in the depth direction of each small region and movement of the irradiation region between the plurality of small regions along the surface direction of the tissue are performed. It may be repeated. In this case, in order to fix the wavelength difference of different wavelengths, it is preferable that the light source is composed of a semiconductor laser having stable properties such as wavelength and phase.

Further, although the polarization detection unit 40 according to the above-described embodiment is provided with six polarization generation units 60, instead of this, s1 = ± 1, s2 = 1, s3 = 1 of the Stokes components of the incident light. You may provide four polarization generation units 60 which generate each of. In this case, one of the four polarized light generating units 60 does not have to have the 1/4 wave plate 63, and the Stokes component of the incident light may be generated only by the linearly polarized light component. Good.

Further, light was switched in order from each of the short wavelength light source 226a and the long wavelength light source 226b and incident on the plurality of polarization generating units 60, but the frequency time-divisioned light was incident on each polarization generating unit 60. May be good. However, if the time division period is too long, the degree of polarization of the object may change. Therefore, it is desirable that the time division period is such that humans cannot see it.

Further, the arrangement position of the polarization generating unit 60 is not limited to the above-described embodiment, and may be arranged around the detection unit 50. However, since the imaging surface 57a of the image sensor 57 is usually formed in a rectangular shape, considering the miniaturization of the entire observation device 100, polarized light is generated above and below the detection unit 50 or in an annular shape as in the above embodiment. It is preferable to arrange the part 60.

Further, an example in which the irradiation optical axis and the light receiving optical axis are shifted from each other in the above-described embodiment is shown, but the present invention is not limited to this, and polarized light is further irradiated from the polarization generating unit 60 in a dark field, and the light from the irradiation region is irradiated. May be received by the image sensor 57. This makes it possible to effectively reduce the specularly reflected light from the irradiated region of the polarized light to be irradiated.

Further, in the polarization generating unit 60 in the above-described embodiment, the polarizing plate 61, the plano-concave lens 62, and the 1/4 wave plate 63 may be adhered to each other and integrated. In this case, the 1/4 wave plate 63 is not provided on the object side of some of the polarizing plates 61 (61c to 61f in the above-described embodiment). Therefore, if the thicknesses of the polarizing plates 61c to 61f are added by the amount of the quarter wave plate 63, the optical path lengths of the respective polarization generating units 60 can be made equal.

Similarly, the exit end 15a of the optical fiber 15 and the polarizing plate 61 may be adhered to each other.

Further, the polarization conversion element of the polarization generation unit 60 is preferably a passive polarization conversion element in which the polarization state obtained by the polarization conversion element does not change from the viewpoint of miniaturization of the observation device 100. From this point of view, the polarizing plate 61 is used in the above-described embodiment. However, since it is sufficient that the polarization state does not change only when the object is irradiated with light, for example, an element in which the liquid crystal element is electrically driven to maintain the polarization state in a predetermined state can also be used as the polarization conversion element.

Further, the observation device 100 according to the above-described embodiment is not limited to the endoscope system 1 and the child endoscope device 120. That is, the observation device 100 is not limited to the parent-child endoscope system. For example, the observation device 100 may be applied to endoscopic systems and endoscopic devices that do not have a working channel 116.

Further, although the example in which the child endoscope device 120 is provided with the determination unit 223a is shown, instead of this, the determination unit 223a may be provided as an external device instead of a part of the child endoscope device 120. In this case, the child endoscope device 120 may be provided with a transmission unit that transmits the image signal processed by the image processing unit 223 of the child endoscope device 120 to the determination unit 223a.

Further, in the parent endoscope system 1A and the child endoscope system 1B, an example of displaying an image on separate displays 312 and 32 is shown, but the images are displayed together on one of the two displays 312 and 32. May be good.

Further, although the Muller matrix M is used as the matrix value of a specific dimension as the value indicating the polarization characteristic of the object to be observed, the Jones matrix J may be used instead. In this case, the number of types of polarized light generated by the polarized light generating unit 60 can be appropriately set.

Further, the values indicating the polarization characteristics of the object of observation ratio of the value of the corresponding matrix elements of the Mueller matrix _{M S, M D (M 1} , M 2), i.e., Mueller matrix _M S, diagonal matrix _{M D} An example using element values is shown. However, instead or in addition, the values of the off-diagonal matrix elements of the Muller matrix may be used. For example, the ratio of the value of the diagonal matrix element to the value of the off-diagonal matrix element is compared with the Muller matrix M _S (M ₁ ) and the Muller matrix M _D (M ₂ ) to determine the state of the object. Of course, this is effective when the approximation does not hold in the description of the transmission optical system. As another example, it may determine the state of the object based on the difference of the difference or the square of the value of the corresponding matrix elements between the Mueller matrix M _S and Mueller matrix M _D.

1 Endoscope system 1A Parent endoscope system 1B Child endoscopy system 100 Observation device 110 Parent endoscopy device 120 Child endoscopy device (endoscope device)
111, 121 Insertion unit 111a, 121a Tube member 123 Operation unit 15 Optical fiber 220 Child side main unit 223 Image processing unit 223a Judgment unit 226 Light source 226a Short wavelength light source 226b High wavelength light source 40 Polarization detection unit 50 Detection unit 57 Image sensor 60 Polarization Generator

Claims (9)

A polarization detector that detects the polarization state of light from an object for each of multiple wavelengths,
A determination unit that determines the state of the object at a depth position corresponding to the wavelength based on the polarization state.
An observation device comprising. The determination unit includes the polarization state of the light from the object irradiated with the light of the first wavelength and the light from the object irradiated with the light of the second wavelength longer than the first wavelength. To determine the state of the object at a position between the depth position where the light of the first wavelength reaches and the depth position where the light of the second wavelength reaches, based on the polarization state of. The observation device according to claim 1. The determination unit is based on the polarization characteristics of the object at the depth position where the light of the first wavelength reaches and the polarization characteristics of the object at the depth position where the light of the second wavelength reaches. The present invention is characterized in that the polarization characteristic of the object is calculated at a position between the depth position where the light of the first wavelength reaches and the depth position where the light of the second wavelength reaches. Item 2. The observation device according to item 2. The third aspect of claim 3, wherein the determination unit determines the state of the object at the depth position by the ratio of at least two values indicating the polarization characteristics among the values indicating the polarization characteristics. Observation device. The observation device according to claim 4, wherein the value indicating the polarization characteristic is a value of a matrix element of the Muller matrix. The observation device according to claim 5, wherein the matrix element is a diagonal matrix element. The polarization detection unit
A plurality of polarization generators that generate light having different polarization states,
A detection unit that detects light from the object irradiated with the light generated by the plurality of polarization generating units, and a detection unit.
The observation device according to any one of claims 1 to 6, wherein the observation device comprises. The stage of detecting the polarization state of light from an object for each of multiple wavelengths,
A step of determining the state of the object at a depth position corresponding to the wavelength based on the polarization state, and
An observation method comprising. An insertion part that is inserted into the body cavity of the subject,
An operation unit for operating the insertion unit is provided.
An endoscope device according to any one of claims 1 to 7, wherein the polarization detection unit of the observation device is arranged in the insertion unit.