JP2007282965A - Endoscopic observation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscopic observation system which can accurately recognize the positions of the blood vessels distributed in object fat, in low-invasive surgery using an endoscope. <P>SOLUTION: This endoscopic observation system identifies a specific region within the living body by utilizing a difference in the spectral absorptivity of near-infrared light with a wavelength of 1,200 nm or more. The endoscopic observation system comprises: a lighting optical system for irradiating the living body with the near-infrared light including a wavelength of 1,200-2,200 nm and in the vicinity of 1,450 nm or 1,900 nm; and an imaging optical system which acquires a near-infrared image for the living body by forming an image on the imaging surface of an imaging element 15 by means of the near-infrared light reflected from the living body. The lighting optical system and the imaging optical system each have a polarizer, and the polarization direction of polarized light incident into the polarizer in the imaging optical system by being reflected from the living body is set orthogonal to the polarization direction of the polarizer in the imaging optical system. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an endoscope observation apparatus.

  In recent years, methods for performing minimally invasive surgery using an endoscope have been established. In order to perform such minimally invasive surgery safely, it is important to recognize the placement (running state) of blood vessels at the site of surgery, and it is accurate even if there are individual differences in the running state of blood vessels. A method that can be confirmed is required.

Further, as a device for recognizing a blood vessel arrangement (running state) in a non-invasive manner, for example, there is a vein authentication device using the fact that there is an individual difference in the running state of a blood vessel as shown in Patent Document 1. Further, efforts are being made to apply such vein authentication devices to the information security field.
JP 2000-339445 A

  A vein authentication device as described in Patent Document 1 used in the field of information security is a device that detects a vein near the skin, such as a palm, using the light absorption characteristics of hemoglobin in blood in a wavelength band of 700 nm to 1000 nm. is there. When a living tissue is irradiated with light, light scattering by the skin is relatively small. For this reason, the blood vessel running state in the vicinity of the skin can be easily detected by using light having a wavelength band of 700 nm to 1000 nm.

  On the other hand, a blood vessel to be subjected to surgery is present not in the vicinity of the skin detected by the vein authentication apparatus as described in Patent Document 1, but in the membrane in the vicinity of the organ. However, since fat is easily accumulated in the membrane in the vicinity of the organ, blood vessels existing in the membrane in the vicinity of the organ are assumed to exist in the fat. Moreover, it is known that among living tissue, light is scattered by fat (fat is a high scatterer). For this reason, even if it is attempted to detect the position of a blood vessel existing in the membrane in the vicinity of a target organ in a minimally invasive surgical operation using an endoscope, non-invasive vein authentication as described in Patent Document 1 of the related art. Using light of a wavelength band of 700 nm to 1000 nm similar to the detection of the position of blood vessels near the skin using the device, the light is attenuated by scattering, and the positions of blood vessels distributed in fat are recognized. Is difficult.

  The present invention has been made in view of the above-described conventional problems, and can accurately recognize the position of a blood vessel distributed in a target fat in a minimally invasive surgical operation using an endoscope. An object of the present invention is to provide an endoscope observation apparatus.

  In order to achieve the above object, an endoscope observation apparatus according to the first invention discriminates a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more. An illumination optical system for irradiating a living body with near-infrared light having a wavelength not less than 1200 nm and not more than 2200 nm and including a wavelength near 1450 nm or near 1900 nm; and the near-infrared light reflected by the living body An imaging optical system that obtains a near-infrared image of the living body by forming an image on an imaging surface, the illumination optical system and the imaging optical system each have a polarizer, and further reflected by the living body to The polarization direction of polarized light incident on the polarizer in the imaging optical system and the polarization direction of the polarizer in the imaging optical system are orthogonal to each other.

  An endoscope observation apparatus according to the second invention is an endoscope observation apparatus that identifies a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more, and is 1200 nm. An illumination optical system for irradiating a living body with near-infrared light having a wavelength of 2200 nm or less and having a wavelength in the vicinity of 1450 nm or 1900 nm, and imaging the near-infrared light reflected by the living body on an imaging surface of an image sensor An imaging optical system that acquires a near-infrared image of the living body, and the illumination optical system and the imaging optical system each have a polarizer on a separate optical path, and the polarizers are polarized with respect to each other. Are arranged so as to be orthogonal to each other.

  An endoscope observation apparatus according to the third invention is an endoscope observation apparatus that identifies a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more. An illumination optical system for irradiating a living body with near-infrared light having a wavelength of 2200 nm or less and having a wavelength in the vicinity of 1450 nm or 1900 nm, and imaging the near-infrared light reflected by the living body on an imaging surface of an image sensor An imaging optical system that acquires a near-infrared image of the living body, and one of the illumination optical system and the imaging optical system has a half-wave plate and a polarizer, and the other is the one It has a feature that polarizers are provided on different optical paths, and the polarizers are arranged so that their polarization directions are the same.

  An endoscope observation apparatus according to the fourth invention is an endoscope observation apparatus that identifies a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more. An illumination optical system for irradiating a living body with near-infrared light having a wavelength of 2200 nm or less and having a wavelength in the vicinity of 1450 nm or 1900 nm, and imaging the near-infrared light reflected by the living body on an imaging surface of an image sensor An imaging optical system that acquires a near-infrared image of the living body, and the illumination optical system and the imaging optical system share a ¼ wavelength plate and a polarizer, and the ¼ wavelength plate and the polarization The optical element is characterized in that the angle formed by the optical axis of the quarter-wave plate and the polarization direction of the polarizer is 45 °.

  In the endoscope observation apparatus according to any one of the first to fourth inventions, a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on the optical path of the illumination optical system. It is preferable.

  In the endoscope observation apparatus according to any one of the first to fourth aspects of the present invention, a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on the optical path of the imaging optical system. It is preferable.

  In the endoscope observation apparatus according to any one of the first to fourth aspects of the present invention, a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on the optical path of the illumination optical system. It is preferable.

  In the endoscope observation apparatus according to any one of the first to fourth aspects of the present invention, a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on the optical path of the imaging optical system. It is preferable.

  ADVANTAGE OF THE INVENTION According to this invention, the endoscope observation apparatus which can recognize correctly the position of the blood vessel distributed in the fat made into object by minimally invasive surgery is obtained.

Prior to the description of the embodiments, the effects of the present invention will be described in detail.
Here, a description will be given using the spectral characteristics of fat and blood vessels when observing blood vessels existing in fat.
FIG. 1 shows the relationship between the spectral absorption characteristics of fat and blood vessels with respect to light having a wavelength of 1000 nm or more. In FIG. 1, the vertical axis represents transmittance (unit:%), and the horizontal axis represents wavelength (unit: nm).
As shown in FIG. 1, it can be seen that there are wavelength bands in which absorption characteristics differ greatly between fat and blood vessels in the vicinity of 1450 nm and 1900 nm. In FIG. 1, these wavelength bands are indicated by using symbols A and B. In these wavelength bands A and B, the degree of light absorption by blood vessels is more than twice the degree of light absorption by fat, and the difference in absorption characteristics is significant compared to other wavelength regions. ing.

Moreover, as shown in FIG. 1, it turns out that the transmittance | permeability of a fat increases substantially proportionally with respect to the wavelength to 2200 nm vicinity. In general, when the transmittance of the scatterer increases in proportion to the wavelength, it is considered that the scattering coefficient of the scatterer decreases in inverse proportion to the wavelength.
Therefore, fat is considered to have a scattering coefficient that decreases inversely with respect to wavelengths up to about 2200 nm, that is, the influence of scattering decreases as the wavelength increases. This means that the light can reach the depth where the blood vessels are distributed through the fat surface with relatively little attenuation by scattering.

Of the light reaching the depth at which the blood vessels are distributed, the light incident on the site where the blood vessels are located is absorbed by the blood vessels by a predetermined amount. The light that has not been absorbed by the blood vessel is reflected (including backscattering) together with the light incident on the site where the blood vessel does not exist, and is emitted from the surface of the fat.
Therefore, it is considered that the position of the blood vessel running in the fat can be recognized by observing reflected light of a predetermined wavelength having different intensities between the site with and without the blood vessel.

However, at this time, as described above, in the wavelength bands A and B, the degree of light absorption by blood vessels is more than twice the degree of light absorption by fat, which is absorbed compared to other wavelength regions. The difference in characteristics is remarkable.
For this reason, if light including wavelengths in these wavelength bands A and B is used as irradiation light for observing blood vessels existing in fat, blood vessels are compared with cases in which light in other wavelength regions is used. The reduction in the amount of light applied to the part where the light is present becomes remarkable. As a result, the difference in the amount of reflected light at the time of observation between the part where the blood vessel exists and the part where it does not exist can be remarkably highlighted, and the position of the blood vessel can be recognized with high accuracy even with weak light it is conceivable that.

Therefore, the present inventor irradiates a living body with light in these wavelength bands (that is, near infrared light including wavelengths of 1200 nm to 2200 nm and near 1450 nm or 1900 nm) in an endoscope observation apparatus. When observing blood vessels distributed in fat using the illumination optical system and an imaging optical system that obtains a near-infrared image of the living body by imaging light reflected by the living body on the imaging surface of the imaging element, The inventors have come up with the idea that an image with a clear contrast between a blood vessel and fat around it can be acquired.
According to the endoscope observation apparatus of the present invention, for example, a blood vessel image 19 as shown in FIG. 2B can be observed. Observation using near-infrared light in a wavelength region where the spectral absorption characteristics of blood vessels and fats do not change significantly (not including wavelengths in the vicinity of 1450 nm and 1900 nm) even at wavelengths of 1200 nm to 2200 nm. In this case, as shown in FIG. 2 (a), there is not enough contrast between the fat 18 and the blood vessel 19, and the running state of the blood vessel cannot be confirmed.

By the way, even if the light irradiated from the illumination optical system is light near 1450 nm or near 1900 nm, a part of the light is reflected on the fat surface without reaching the blood vessel. However, when light reflected from the fat surface enters the imaging optical system, halation occurs, and the contrast of the blood vessel image is significantly reduced.
Therefore, in the endoscope observation apparatus of the present invention, as countermeasures for preventing halation, each of the illumination optical system and the imaging optical system has a polarizer, and further reflected by the living body to the polarizer in the imaging optical system. The polarization direction of the incident polarized light is orthogonal to the polarization direction of the polarizer in the imaging optical system.

For example, the illumination optical system and the imaging optical system have polarizers on separate optical paths, and the polarizers are arranged so that their polarization directions are orthogonal to each other.
In addition, for example, one of the illumination optical system and the imaging optical system has a half-wave plate and a polarizer, and the other has a polarizer on an optical path different from the one, and each of the polarizers They are arranged so that their polarization directions are the same.
Further, for example, the illumination optical system and the imaging optical system share a ¼ wavelength plate and a polarizer, and the ¼ wavelength plate and the polarizer are connected to the optical axis of the ¼ wavelength plate and the polarizer. It arrange | positions so that the angle which a polarization direction may make may be 45 degrees.

  In this way, the light emitted from the illumination optical system has a certain polarization direction and is reflected by the fat surface. Almost all of the light reflected by the fat surface maintains a uniform polarization state, similar to the incident light. And the light which injects into the polarizer with which an imaging optical system is equipped is light-shielded via the polarizer with which this imaging optical system is equipped. Therefore, according to the endoscope observation apparatus of the present invention, it is possible to prevent halation due to light reflected on the fat surface. On the other hand, the light reflected in the fat (the depth at which blood vessels are distributed) is disturbed in polarization due to scattering or the like, and becomes almost non-polarized. When the light enters the polarizer included in the imaging optical system, a part of light whose polarization direction matches that of the polarizer of the imaging optical system is transmitted. For this reason, blood vessels distributed inside the fat can be observed.

In general, the light backscattered in the vicinity of the surface of the observation object has a small change in the polarization state. Therefore, a part of the light incident on the observation object is kept in the polarization state. Similarly, in the case of fat, the back-scattered light near the surface has a small change in polarization state.
However, since blood vessels in fat are present at a depth of about 2 to 3 mm from the surface, the light scattered back in the vicinity of the surface can become noise when observing a blood vessel image in fat.
However, according to the endoscope observation apparatus of the present invention, as described above, each of the illumination optical system and the imaging optical system has a polarizer, and the polarizer in the imaging optical system is reflected by the living body. Since the polarization direction of the polarized light incident on the light beam and the polarization direction of the polarizer in the imaging optical system are orthogonal to each other, these noises can be reduced by cutting with the polarizer in the imaging optical system.

  In the endoscope observation apparatus according to any one of the first to fourth inventions, it is preferable that a band pass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the illumination optical system. .

  In the endoscope observation apparatus according to any one of the first to fourth aspects of the invention, it is preferable that a bandpass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the imaging optical system. .

  In the endoscope observation apparatus according to any one of the first to fourth inventions, it is preferable that a band pass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the illumination optical system. .

  In the endoscope observation apparatus according to any one of the first to fourth inventions, it is preferable that a band pass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the imaging optical system. .

  Further, as the endoscope observation apparatus according to the fifth invention, in the endoscope observation apparatus according to the first to fourth inventions, a reflection that can be inserted into a space opposite to the imaging optical system with the living body interposed therebetween. It is preferable to provide a plate.

  In the endoscope observation apparatus according to the fifth aspect of the present invention, it is preferable that a depolarizing plate is added to the reflecting plate.

  In the endoscope observation apparatus according to the fifth aspect of the present invention, it is preferable that a quarter wave plate is added to the reflecting plate.

  An endoscope observation apparatus according to the sixth invention is an endoscope observation apparatus that identifies a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more. A light source unit that generates near-infrared light having a wavelength of 2200 nm or less and having a wavelength near 1450 nm or 1900 nm and near-infrared light having a wavelength of 1200 to 2200 nm and not including any wavelength near 1450 nm or 1900 nm; An illumination unit that is optically connected to the light source unit and illuminates the different near-infrared light in a different illumination state (that is, a state of illuminating illumination light having different illumination wavelengths) with respect to the living body; An imaging unit that obtains a near-infrared image of the living body by imaging the reflected different near-infrared light on an imaging surface of an imaging device An image processing unit for processing the different near-infrared images acquired by the imaging unit, and the image processing unit generates images based on the different near-infrared images captured in different illumination states. It is configured to perform contrast enhancement of a specific part in the body.

The site to be observed does not necessarily have a flat structure. For this reason, the illuminance of the illumination light on the surface of the observation target part may become non-uniform depending on the positional relationship between the illumination light emitting part from the illumination optical system and the observation target part. In such a case, the intensity of light that reaches and reflects the depth of travel of the blood vessel also becomes non-uniform, so that a high-contrast blood vessel image cannot be drawn over the entire image of the observation target region. .
By the way, as shown in FIG. 1, in a region where a blood vessel exists, the light absorptance in the wavelength band of 1450 nm ± 100 nm and the wavelength band of 1900 nm ± 100 nm is in other wavelength regions (for example, 1700 ± 100 nm). Higher than light absorption.

However, in the endoscope observation apparatus according to the sixth aspect of the invention, the absorption characteristics of the blood vessels are used to make two different illumination states (that is, light in a wavelength band having a high degree of absorption in the blood vessels here). Predetermined image processing (for example, light of two different illumination wavelengths) is performed on the image data of the observation target part imaged in a state where illumination light of two different illumination wavelengths is illuminated as light in other wavelength bands. The contrast between the blood vessel image and the background image is enhanced by calculating the illuminance ratio of the image obtained by illuminating the image and applying image processing such as binarization of the image data in accordance with the illuminance ratio. Like to do.
In this way, the site where the blood vessel exists and the site where it does not exist can be observed as a contrast-enhanced image, for example, binarized with white and black over the entire observation image. Even if the target part does not have a flat structure, the position of the blood vessel in the observation target part can be clearly recognized.

  An endoscope observation apparatus according to the seventh invention is an endoscope observation apparatus that identifies a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more, and is 1200 nm. A plurality of light source units that generate near infrared light having a wavelength of 2200 nm or less and having a wavelength near 1450 nm or near 1900 nm, and optically connected to each of the light source units, and using different near infrared light to a living body. On the other hand, a plurality of illumination units that illuminate in different illumination states (in this case, illumination light from different illumination directions) and different near-infrared lights reflected by the living body are applied to the imaging surface of the image sensor. An imaging unit that acquires a near-infrared image of the living body by forming an image, and an image processor that processes the different near-infrared images acquired by the imaging unit. A unit, and the image processing unit is configured to perform contrast enhancement of a specific part in a living body based on the different near-infrared images captured in different illumination states. .

Depending on the direction of illumination of the observation target region, the illuminance of the illumination light on the surface of the observation target region varies greatly, and even if there is no blood vessel, there is a region where the light obtained through the imaging element becomes dark, The contrast between the image of such a part and the blood vessel image may be weakened. For this reason, with illumination from one direction, there may be a case where a blood vessel image with good contrast cannot be drawn over the entire image of the observation target region.
By the way, as described above, in the region where the blood vessel exists, the light absorption rate in the wavelength band of 1450 nm ± 100 nm and the wavelength band of 1900 nm ± 100 nm is the absorption of light in other wavelength regions (for example, 1700 ± 100 nm). High compared to the rate.
For this reason, when light is irradiated to the observation target part from different directions, the brightness change of the light obtained through the imaging element is large depending on the irradiation direction in the part other than the blood vessel, whereas in the blood vessel, the irradiation direction Therefore, the change in the brightness of light obtained through the image sensor is very small.
That is, for example, a portion that is imaged dark when illuminated from one of two different directions can be imaged brightly when illuminated from the other direction. On the other hand, in the blood vessel, the brightness of the obtained light hardly changes regardless of the direction of irradiation, and the image is dark.
Therefore, when two pixel signals obtained by illumination from two different directions are added together and the average is calculated, a dark region disappears when a region other than a blood vessel is viewed in the entire image region, and thus a blood vessel region that is imaged darkly The contrast with can be emphasized.

However, in the endoscope observation apparatus according to the seventh aspect of the invention, using the absorption characteristics of the blood vessels, the illumination light is illuminated in two different illumination states (in this case, illumination light is illuminated from two different illumination directions). By performing predetermined image processing (for example, image processing such as adding two pixel signals obtained by illumination from two different directions and calculating an average thereof) on the image data of the observed site to be observed, The contrast between the blood vessel image and the background image can be enhanced.
In this way, the position of the blood vessel in the observation target part can be clearly recognized even if the observation target part does not have a flat structure.

  Further, as the eighth invention, in the endoscope observation apparatus of the sixth or seventh invention, the illumination unit and the imaging unit each have a polarizer, and further reflected by the living body to It is preferable that the polarization direction of the polarized light incident on the polarizer in the imaging unit is orthogonal to the polarization direction of the polarizer in the imaging unit.

  As the ninth invention, in the endoscope observation apparatus according to the eighth invention, the light source unit and the illumination unit are connected via a light guide cable, and a polarizer in the illumination unit is the light. It is preferable that the guide cable and the lighting unit are rotatably arranged at the connection portion.

  As the tenth invention, in the endoscope observation apparatus according to the eighth invention, the illumination unit and the imaging unit each have the polarizer on separate optical paths, and the polarizers are It is preferable that the polarization directions are arranged to be orthogonal to each other.

  As the eleventh invention, in the endoscope observation apparatus according to the eighth invention, one of the illumination unit and the imaging unit has a half-wave plate and the polarizer, and the other is It is preferable that the polarizer is provided on an optical path different from the one, and the polarizers are arranged so that their polarization directions are the same.

  As the twelfth aspect of the invention, in the endoscope observation apparatus of the eighth aspect of the invention, the illumination unit and the imaging unit share the ¼ wavelength plate and the polarizer, and the ¼ wavelength plate. And the polarizer are preferably arranged such that an angle formed by the optical axis of the quarter-wave plate and the polarization direction of the polarizer is 45 °.

  In the endoscope observation apparatus according to any one of the sixth to twelfth inventions, a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on the optical path of the illumination unit. It is preferable.

  In the endoscope observation apparatus according to any one of the sixth to twelfth inventions, a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on the optical path of the imaging unit. It is preferable.

  In the endoscope observation apparatus according to any one of the sixth to twelfth inventions, a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on the optical path of the illumination unit. It is preferable.

  In the endoscope observation apparatus according to any one of the sixth to twelfth inventions, a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on the optical path of the imaging unit. It is preferable.

  In the endoscope observation apparatus according to any one of the sixth to twelfth inventions, it is preferable that a bandpass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the illumination unit. .

  In the endoscope observation apparatus according to any of the sixth to twelfth inventions, it is preferable that a bandpass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the imaging unit. .

  In the endoscope observation apparatus according to any one of the sixth to twelfth inventions, it is preferable that a band pass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the illumination unit. .

  In the endoscope observation apparatus according to any one of the sixth to twelfth inventions, it is preferable that a band pass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the imaging unit. .

  Further, as the endoscope observation apparatus according to the thirteenth invention, in the endoscope observation apparatus according to the sixth to twelfth inventions, a reflector that is inserted into a space opposite to the imaging unit with the living body interposed therebetween. May be provided.

  In the endoscope observation apparatus according to the thirteenth aspect of the present invention, it is preferable that a depolarizing plate is added to the reflecting plate.

  In the endoscope observation apparatus according to the thirteenth aspect of the invention, it is preferable that a quarter wave plate is added to the reflecting plate.

FIG. 3 is an explanatory diagram illustrating a schematic configuration of the endoscope observation apparatus according to the first embodiment of the present invention.
The endoscope observation apparatus according to the first embodiment is an endoscope observation apparatus that observes the running state of blood vessels in fat. As shown in FIG. 3, the endoscope observation apparatus according to the first embodiment is a living body. A video scope 24 configured to attach a camera head 23 incorporating an image sensor 15 to a scope 22 to be inserted into the abdomen 2B of the subject and obtain an image of the observation target region 40; A light source device 25 that supplies illumination light to the part 40, an image processing unit 26 that processes a signal from the image sensor 15 incorporated in the camera head 23, and a video signal that is output from the image processing unit 26 is displayed. A TV monitor 27 is used.

The scope 22 includes a rigid insertion portion 31, a grip portion 32 provided subsequent thereto, and an eyepiece portion 33 provided at the rear end of the grip portion 32, and a light guide is provided on a side cap of the grip portion 32. A cable 34 is connected.
A light guide 35 for transmitting illumination light is inserted into the insertion portion 31, and the light guide 35 can be attached to and detached from the light source device 25 via a light guide cable 34 by a light guide connector 36 provided at an end thereof. It is connected.

A lamp lighting control circuit 37 is provided in the light source device 25, and a halogen lamp or the like that emits light in the near infrared region from the lamp lighting control circuit 37 to a wavelength of 1200 nm to 2200 nm and including a wavelength in the vicinity of 1450 nm or 1900 nm. The lamp 38 is supplied with power.
The light emitted from the lamp 38 is condensed on the incident end face of the light guide 35 of the light guide connector 36 by the condenser lens 39 disposed on the illumination optical path, and is guided by the light guide 35 to the distal end (outgoing portion) of the insertion portion 31. End face).
The light emitted from the distal end surface of the light guide 35 is applied as illumination light to the observation target portion 40 such as the stomach in the abdomen 2B.

  An observation window is provided adjacent to the illumination window at the distal end of the insertion portion 31, and an optical image of the observation target portion 40 acquired by the objective lens 41 through the observation window is transferred to the rear end surface of the relay optical system by the relay optical system 42. Until it is transmitted. The image of the observation target portion 40 transmitted to the rear end surface of the relay optical system 42 is imaged on the imaging surface of the imaging device 15 by the imaging lens 44 disposed behind the eyepiece lens 43 through the eyepiece lens 43. It is like that.

  In the present application, for example, an assembly of optical members that irradiate near-infrared light to the observation target region 40 including the light source device 25, the light guide 35, and the illumination window in the endoscope observation apparatus of the first embodiment. This corresponds to the illumination optical system of the present invention. Further, for example, in the endoscope observation apparatus according to the first embodiment, an image of the observation target portion 40 including the observation window, the objective lens 41, the relay optical system 42, the eyepiece lens 43, and the imaging lens 44 is captured by the imaging element 15. An assembly of optical systems that form an image on a surface corresponds to the imaging optical system of the present invention. Further, for example, the light source device 25 in the endoscope observation apparatus of Embodiment 1 corresponds to the light source unit of the present invention. In addition, for example, in the endoscope observation apparatus according to the first embodiment, the scope 22 including the light guide 35 and the assembly of optical members that irradiate the observation target portion 40 with near-infrared light is included in the illumination unit of the present invention. Equivalent to. In addition, for example, in the endoscope observation apparatus according to the first embodiment, the video scope 24 including an assembly of optical systems that forms an image of the observation target portion 40 on the imaging surface of the imaging element 15 is an imaging according to the present invention. Corresponds to a unit.

  Here, in the endoscope observation apparatus according to the first embodiment, the polarizers 45a and 45b are respectively provided in the observation window and the illumination window at the distal end of the insertion portion 31 as halation preventing means, and the polarizers 45a and 45b are provided. Is configured such that the polarization direction of the polarized light reflected by the observation target portion 40 and incident on the polarizer 45a in the imaging optical system is orthogonal to the polarization direction of the polarizer 45a in the imaging optical system.

  Further, the endoscope observation apparatus according to the first embodiment has a characteristic of transmitting a wavelength band of 1450 nm ± 100 nm on the optical path between the imaging lens 44 and the imaging element 15 as shown in FIG. A band-pass filter 13 is disposed.

FIG. 5 is an explanatory diagram illustrating an arrangement example of two polarizers provided at the distal end portion of the insertion portion 31 as a halation preventing unit in the endoscope observation apparatus according to the first embodiment.
In the arrangement example shown in FIG. 5, the two polarizers 45 a and 45 b are arranged so that the polarization directions are orthogonal to each other, and are integrated as one polarizing element 45.
Specifically, the polarizer 45a in the illumination optical system is disposed so as to cover the illumination window. The polarizer 45b in the imaging optical system covers the observation window and is arranged so that the polarization direction is orthogonal to the polarization direction of the polarizer 45a.

In the endoscope observation apparatus according to the first embodiment configured as described above, the illumination light emitted from the light source device 25 and passed through the light guide 25 is maintained in a fixed polarization state via the polarizer 45a, and is observed. The part 40 is irradiated.
Of the illumination light applied to the observation target region 40, the light that passes through the fat 18 and reaches the region where the blood vessel 19 is distributed and is reflected (including backscattering) is observed in a state where the polarization is eliminated. The light is emitted from the surface of the target portion 40 and enters the polarizer 45b disposed in the observation window. At this time, light that does not match the polarization direction of the polarizer 45b is blocked, but part of light that matches the polarization direction of the polarizer 45b passes through the polarizer 45b and reaches the imaging surface of the image sensor 15 optically. And a blood vessel image is formed.
On the other hand, the light reflected from the surface of the observation target portion 40 maintains the polarization state of the illumination light, and the polarization direction when entering the polarization element 45 is orthogonal to the polarization direction of the polarization element 45. Light cannot be transmitted through the polarizing element 45 and is blocked.
For this reason, according to the endoscope observation apparatus of Example 1, due to the effects of the polarizers 45a and 45b, the surface of the observation target part 40 is not affected by the positional relationship between the distal end of the insertion portion of the scope 22 and the observation target part 40. Halation due to reflected light can be suppressed.

As described with reference to FIG. 1, in the vicinity of 1450 nm, the degree of light absorption by blood vessels is more than twice the degree of absorption by fat, and a clear contrast can be given to the blood vessel image.
However, in the endoscope observation apparatus according to the first embodiment, an image is constructed using light in a band of ± 100 nm centered on 1450 nm via the bandpass filter 13, so that observation is performed due to the influence of the polarizer. A bright blood vessel image can be drawn regardless of the amount of light passing through the window.
Note that the same effect can be obtained by replacing the band-pass filter 13 with one having a characteristic of transmitting a wavelength band of 1900 ± 100 nm as shown in FIG. 4B. In addition, the polarizer 45b in the imaging optical system is not necessarily arranged in the observation window. If the polarizer 45b is arranged in a space that can be arranged from the observation window to the imaging surface of the imaging element 15, it is the same as the case where it is arranged in the observation window. An effect is obtained.

FIG. 6 is an explanatory diagram illustrating a schematic configuration of an endoscope observation apparatus according to a modification of the first embodiment.
Other than the light source device 25 ′ in the endoscope observation apparatus according to the modification of the first embodiment and the means (polarizing element 45) for preventing the halation caused by the light reflected on the surface of the observation target portion 40 arranged at the distal end of the insertion portion 31. Since this configuration is the same as the above-described device configuration, description thereof will be omitted.
In the endoscope observation apparatus according to the modification of the first embodiment, the band pass filter 13 having the characteristic of transmitting a wavelength band of 1450 nm ± 100 nm is disposed on the optical path of the light source device 25 ′.

FIG. 7 is an explanatory view showing a configuration example of the light source device 25 ′, (a) is a plan view showing the configuration of a rotating disk arranged in the optical path of the light source device 25 ′, and (b) is a light source device 25 ′. It is a schematic block diagram which shows the example of arrangement | positioning of the rotating disk in.
Two types of band-pass filters are arranged on a concentric circle on the rotating disk. One of them is a band-pass filter having a characteristic of transmitting a wavelength band of 1450 nm ± 100 nm as shown in FIG. The other is a bandpass filter having a characteristic of transmitting a wavelength band of 1700 nm ± 100 nm as shown in FIG.
Note that a bandpass filter having a characteristic of transmitting a wavelength band of 1900 nm ± 100 nm may be arranged instead of a bandpass filter having a characteristic of transmitting a wavelength band of 1450 nm ± 100 nm.
In such a configuration, the two types of band-pass filters are sequentially inserted into the light source optical path by rotating the rotating disk around the rotation axis at a constant speed. As a result, the observation target region 40 is alternately irradiated with light of two types of wavelength bands through the illumination window.

By the way, the observation target part 40 does not necessarily have a flat structure. For this reason, depending on the positional relationship between the illumination window and the observation target region 40, the illuminance of the illumination light on the surface of the observation target region 40 may be uneven. In such a case, since the intensity of the light that reaches and reflects the depth of travel of the blood vessel also becomes non-uniform, it is possible to render a blood vessel image with good contrast over the entire image of the observation target region 40. Can not.
Therefore, in the endoscope observation apparatus according to the modification of the first embodiment, the light source device 25 ′ shown as an example of the configuration in FIG. 7B is used, and the wavelength region is relatively close to the wavelengths of 1450 nm and 1900 nm. In the graph shown in FIG. 1, the observation target region 40 is irradiated with light having a wavelength band of 1700 nm ± 100 nm that has almost no difference between the light absorption characteristic of fat and the light absorption characteristic of the blood vessel, and the blood vessel travels. The image of the light reaching and reflecting to a certain depth is also reflected by irradiating the observation target region 40 with light having a wavelength band of 1450 nm ± 100 nm or a wavelength band of 1900 ± 100 nm to reach the depth at which the blood vessel travels. The image is acquired along with the light image. Then, the image processing unit 26 normalizes by dividing the image signal imaged through the light in the wavelength band of 1450 nm ± 100 nm or 1900 ± 100 nm by the image signal imaged through the light in the wavelength band of 1700 nm ± 100 nm. By doing so, a high-contrast blood vessel image is drawn.

FIG. 9 is a flowchart illustrating an example of the contrast enhancement processing procedure of the image of the observation target portion 40 in the endoscope observation apparatus according to the modification of the first embodiment. In the example of FIG. 9, light having a wavelength band of 1450 nm ± 100 nm and light having a wavelength band of 1700 nm ± 100 nm are used.
First, the observation target region 40 is irradiated with light having a wavelength band of 1450 nm ± 100 nm via the light source device 25 ′, and then reaches the region where the blood vessel 19 is distributed and is reflected (backscattered), and the polarizer 45b is The passed light is imaged by the image sensor 15 to obtain a first image signal (here, image signal λ1) (step S1).
In addition, the observation target region 40 is irradiated with light having a wavelength band of 1700 nm ± 100 nm via the light source device 25 ′, and then reaches the region where the blood vessel 19 is distributed and is reflected (backscattered), and the polarizer 45b is The passed light is imaged by the image sensor 15 to obtain a second image signal (here, image signal λ2) (step S2).

The image processing unit 26 divides the image signal λ1 by the image signal λ2 for each pixel area captured by the image sensor 15 (that is, here, the image signal λ1 ÷ image signal λ2). Then, when λ1 / λ2≈1, image processing is performed so that the image of the pixel area is displayed as white, and otherwise (that is, λ1 / λ2 << 1) Image processing is performed so that the image is displayed as black (step S3).
As described above, the image processing unit 26 binarizes the image in each pixel region based on the image signal captured through the light in the wavelength band of 1700 nm ± 100 nm, and displays the binarized image on the TV monitor 27. I try to do it.

As shown in FIG. 1, in a region where a blood vessel exists, the light absorptance in the wavelength band of 1450 nm ± 100 nm and the wavelength band of 1900 nm ± 100 nm is higher than that of light in other wavelength regions (for example, 1700 ± 100 nm). Higher than the absorption rate. For this reason, the value of the image signal λ1 obtained through the light in the wavelength band of 1450 nm ± 100 nm is extremely smaller than that of the image signal λ2 obtained through the light in the wavelength band of 1700 nm ± 100 nm. Therefore, at a site where a blood vessel exists, the value obtained by dividing the image signal λ1 by the image signal λ2 is a value much less than 1.
On the other hand, in the region where the blood vessel does not exist, the absorption rate of light in the wavelength band of 1450 nm ± 100 nm and the wavelength band of 1900 nm ± 100 nm and the absorption rate of light in other wavelength regions (for example, 1700 ± 100 nm) are not much. There is no difference. Therefore, at a site where a blood vessel exists, the value obtained by dividing the image signal λ1 by the image signal λ2 is a value approximate to 1.

The image processing unit 26 in the endoscope observation apparatus according to the modification of the first embodiment uses the absorption characteristics of the blood vessels to use two different illumination states (that is, wavelengths having a high degree of absorption in the blood vessels here). The above-described image processing is performed on the image data of the observation target portion 40 imaged in a state where illumination light having two different illumination wavelengths is illuminated (such as light in a band and light in other wavelength bands). Thus, the contrast between the blood vessel image and the background image is enhanced.
Therefore, according to the endoscope observation apparatus of the modification of the first embodiment, the site where the blood vessel exists and the site where the blood vessel does not exist are observed as a binarized image of white and black over the entire observation image. Therefore, even if the observation target part 40 does not have a flat structure, the position of the blood vessel 19 in the observation target part 40 can be clearly recognized.

  The configuration of the polarizing element including the polarizer as the halation preventing means in the endoscope observation apparatus of the present invention is the polarization direction of the polarized light that is reflected by the observation target portion 40 and incident on the polarizer 45a in the imaging optical system. As long as the polarization direction of the polarizer 45a in the imaging optical system is orthogonal, the arrangement is not limited to the arrangement example shown in FIG. 5 and may be other configurations.

FIG. 10 is an explanatory view showing another configuration example of the halation preventing means in the endoscope observation apparatus of the present invention, where (a) is a side view and (b) is a plan view.
The antihalation means of the configuration example shown in FIG. 10 is composed of one polarizing element 45 including a quarter-wave plate 45c and a polarizer 45a arranged in order from the object side at the distal end of the insertion portion 31. . The polarizing element 45 is shared by the illumination optical system and the imaging optical system.
The quarter-wave plate 45c and the polarizer 45a are arranged such that the polarization direction of the polarizer 45a makes an angle of 45 degrees with respect to the optical axis of the quarter-wave plate 45c.
In the endoscope observation apparatus according to the modification of the first embodiment, the halation preventing means having the configuration example shown in FIG. 10 is employed.

  In the endoscope observation apparatus according to the modified example of the first embodiment configured as described above, the light emitted from the illumination window is the light having passed through the polarizer 45a to be polarized in a predetermined polarization direction, and is further a quarter. By passing through the wave plate, it is converted into circularly polarized light. Then, the circularly polarized light reflected on the surface of the observation target portion 40 is incident on the quarter-wave plate 45c again and is transmitted through the quarter-wave plate 45c, so that the polarization is perpendicular to the polarization direction of the polarizer 45a. Converted. For this reason, the polarized light from the quarter-wave plate 45c incident on the polarizer 45a is blocked without being transmitted.

  The halation preventing means shown in FIGS. 5 and 10 can be applied to both the first embodiment and the modified example of the first embodiment.

FIG. 11 is an explanatory view showing still another configuration example of the halation preventing means applicable to the endoscope observation apparatus of the present invention, and (a) shows the arrangement relationship between the illumination window and the observation window and the halation preventing means. (B) is a side view of the halation preventing means in (a), and (c) is a plan view of (b).
The antihalation means of the configuration example shown in FIG. 11 has a half-wave plate 45c ′ and a polarizer 45a in order from the object side on one of the observation window and the illumination window, and only the polarizer 45b on the other. It is configured. In this case, the polarizers 45a and 45b are arranged so that their polarization directions are the same. For convenience of explanation, FIG. 11 shows a configuration in which the observation window includes the half-wave plate 45c ′ and the polarizer 45a, and the illumination window includes the polarizer 45b.

  According to the endoscope observation apparatus employing the antihalation means configured as shown in FIG. 11, the light emitted from the illumination window is the light having passed through the polarizer 45b and polarized in a predetermined polarization direction. Then, the polarized light reflected by the surface of the observation target portion 40 is converted into polarized light whose polarization direction is rotated by 90 degrees by passing through the half-wave plate 45c '. For this reason, the polarized light from the half-wave plate 45c 'entering the polarizer 45a is blocked without being transmitted.

Furthermore, as shown in FIG. 3, the endoscope observation apparatus according to the first embodiment includes a reflector 51 that can be inserted into a space opposite to the imaging optical system with a living body interposed therebetween.
When the observation target portion 40 is, for example, the stomach omentum 18, the blood vessel 19 exists in the fat accumulated in the stomach omentum 18, but may be detached from the stomach.
However, according to the endoscope observation apparatus of the first embodiment, in such a case, the reflecting plate 51 is inserted from a place different from where the scope 22 is inserted into the body, and the observation target part 40 can be positioned in a space opposite to the tip of the insertion portion 31 of the scope 22. If it does in this way, the light which permeate | transmitted the observation object site | part 40 will be reflected through the reflecting plate 51, will be irradiated again to the observation object site | part 40, and an imaging optical system will be used also about the light which permeate | transmitted the observation object region 40. It is possible to enhance the intensity of the observation image. As a result, the contrast between the blood vessel and other portions becomes clearer, and blood vessels distributed in fat can be further easily identified.
In the case of using the reflecting plate 51, even if the illumination light emitted from the lighting window directly hits the reflecting plate 51 and the light reflected by the reflecting plate 51 may enter the observation window, FIG. 10. Such light can be blocked by using the halation removing means as shown in FIG.

  Further, a depolarizing plate may be added to the reflecting surface of the reflecting plate 51 in the endoscope observation apparatus according to the first embodiment. If it does in this way, all the light reflected by the reflecting plate 51 will be in a non-polarization state among the lights by which the polarization state was maintained when permeate | transmitting the observation object site | part 40. FIG. For this reason, when light that passes through the observation target portion 40 again and includes blood vessel image information enters the observation window, the light is taken into the objective lens 41 without being completely blocked by the halation preventing means.

FIG. 12 is an explanatory diagram illustrating a schematic configuration of the endoscope observation apparatus according to the second embodiment of the present invention.
The endoscope observation apparatus according to the second embodiment is configured by further including a second illumination optical system in addition to the endoscope observation apparatus according to the first embodiment or the modification of the first embodiment illustrated in FIG. 3 or FIG. Yes.
The second illumination optical system includes a second light source device 55, a second light guide cable 65, and an illumination sheath 66.
The second light source device 55 is configured in the same manner as the first light source device 25.
Similar to the light guide 35 in the first light source device 25, the second light guide cable 65 includes a second light guide (not shown). The second light guide cable 65 has one end connected to the second light source device 55 and the other end connected to the illumination sheath 66.
And the 2nd illumination optical system comprised in this way inserts a 2nd light guide through the sheath 66 for illumination from another insertion part of the abdominal part 2B, and the illumination transmitted by the 2nd light guide It is possible to irradiate the observation target region 40 with light.

  For example, like the reflector 51 in the endoscope observation apparatus of the first embodiment, the second light guide cable 65 including the second light guide enters the space opposite to the scope 22 of the observation target portion 40. Thus, the observation target region 40 can be transmitted and illuminated from the space opposite to the scope 22.

In this case, a polarizer (not shown) is attached to the distal end portion of the illumination sheath 66 in a rotatable state, and an operation handle (not shown) provided on the hand side operation portion 66a of the illumination sheath 66 is operated. By doing so, the polarization direction of the illumination light that passes through this polarizer and is irradiated onto the observation target region is in a state of being orthogonal to the polarization direction of the polarizer in the imaging optical system attached to the scope 22 side. It is desirable that the structure be adjustable.
Further, it is desirable that the vicinity of the distal end 66b of the illumination sheath 66 is made of a bendable member such as a soft tube, and that the bendable structure is provided by an operation handle provided on the hand side operation portion 66a.

  Further, a relay optical system (not shown) is inserted from the proximal side operation portion 66a to the distal end portion of the illumination sheath 66, and a joint portion (illustrated) is connected to the proximal side operation portion 66a to connect the relay optical system and the second light guide. (Omitted) may be provided. In that case, if the polarizer attached to the illumination sheath 66 is rotatably arranged via the joint portion, illumination light having a desired polarization state is created via the rotation of the joint portion, and the polarization is preserved in the relay optical system. In this state, the observation target region 40 can be irradiated.

  According to such a configuration, the polarization direction of the illumination light emitted through the polarizer attached to the illumination sheath 66 without the need for a complicated rotation mechanism, and the imaging attached to the scope 22 side. It is possible to adjust so as to be orthogonal to the polarization direction of the polarizer in the optical system.

  In addition, an optical member that bends the optical axis of the relay optical system to a desired angle is preferably provided at the distal end portion of the illumination sheath 66. By doing so, the illumination direction can be easily adjusted. In addition, a reflecting plate, a prism mirror, etc. can be used as an optical member which bends the optical axis of a relay optical system to a desired angle.

According to the endoscope observation apparatus of the second embodiment configured as described above, the first light source 25 and the second light source 55 are turned on at the same time, and transmitted illumination and epi-illumination are performed simultaneously on the observation target portion 40. Thus, it is possible to more clearly depict the running state of the blood vessel existing in the observation target portion 40 while preventing halation.
In addition, the first light source device 25 and the second light source device 55 are selectively turned on, and image data of the observation target region 40 imaged in two different illumination states are transmitted via the image processing unit 26 to a predetermined value. By adding arithmetic processing, contrast enhancement of the blood vessel image can be performed.

FIG. 13 is a flowchart illustrating an example of the contrast enhancement processing procedure of the image of the observation target portion 40 in the endoscope observation apparatus according to the second embodiment. In the example of FIG. 13, both the first light source device 25 and the second light source device 55 are configured to emit light having a wavelength band of 1450 nm ± 100 nm as illumination light. Of course, both may be configured to emit light having a wavelength band of 1900 nm ± 100 nm as illumination light.
First, when one of the first light source 25 and the second light source 55 is turned on and the other is turned off, and the illumination is performed from the direction of one light source that is turned on (here, the A direction), the blood vessels 19 are distributed. The first image signal (here, referred to as image signal A) is acquired by imaging the light that has reached the region to be reflected, reflected (backscattered), and passed through the polarizer 45b with the imaging device 15 (step S11). .
Next, the region where the blood vessels 19 are distributed when the other one of the first light source 25 and the second light source 55 is turned on and the other light source is turned off and illuminated from the direction of the other light source that is turned on (here, B direction). The light that has reached and reflected (backscattered) and passed through the polarizer 45b is picked up by the image pickup device 15 to obtain a second image signal (referred to here as image signal B) (step S12).

  The image processing unit 26 sums up the pixel signal A and the pixel signal B for each pixel area imaged by the image sensor 15 and calculates the average (that is, (image signal A + image signal B) / 2). ).

  Depending on the direction of illumination of the observation target region 40, the illuminance of the illumination light on the surface of the observation target region 40 varies greatly, and there is a region where the light obtained through the imaging element 15 becomes dark even if there is no blood vessel. And the contrast between the image of such a part and the blood vessel image may be weakened. For this reason, with illumination from one direction, there may be a case where a blood vessel image with good contrast cannot be drawn over the entire image of the observation target region 40.

As shown in FIG. 1, in a region where a blood vessel exists, the light absorptance in the wavelength band of 1450 nm ± 100 nm and the wavelength band of 1900 nm ± 100 nm is higher than that of light in other wavelength regions (for example, 1700 ± 100 nm). Higher than the absorption rate. For this reason, when the observation target region 40 is irradiated with light from a plurality of different directions, the change in brightness of light obtained through the image sensor 15 is large depending on the irradiation direction in a region other than the blood vessel, whereas in the blood vessel, The change in the brightness of light obtained via the image sensor 15 is very small depending on the irradiation direction.
That is, in the endoscope observation apparatus according to the second embodiment, when the irradiation is performed from one of the first light source 25 and the second light source 55 (direction A), the portion that is darkly imaged is the other (B When illuminated from the (direction), bright images can be taken. On the other hand, in the blood vessel, the brightness of the obtained light hardly changes regardless of whether the irradiation is performed from the A direction or the B direction.
Therefore, when the pixel signal A and the pixel signal B are added together and the average is calculated, the dark region disappears when the region other than the blood vessel is viewed in the entire image region, so that the contrast with the blood vessel region that is imaged darkly is enhanced. Can do.

The image processing unit 26 in the endoscope observation apparatus according to the second embodiment uses the absorption characteristics of the blood vessels to make two different illumination states (that is, here, illumination light is illuminated from two different illumination directions). By applying the image processing as described above to the image data of the observation target region 40 imaged in step 1, the contrast between the blood vessel image and the background image can be enhanced.
For this reason, according to the endoscope observation apparatus of Example 2, even if the observation target part 40 does not have a flat structure, the position of the blood vessel 19 in the observation target part 40 can be clearly recognized.

The endoscope observation apparatus according to the third embodiment is substantially the same as the endoscope observation apparatus according to the first embodiment shown in FIG. For convenience, description will be made with reference to FIG.
The halation preventing means of the third embodiment is disposed on the observation window and the illumination window of the scope 22 so that the polarization directions thereof are orthogonal to each other, and on the reflection surface side of the reflection plate 51. It consists of a quarter wave plate.

In the endoscope observation apparatus according to the third embodiment configured as described above, the reflection plate 51 is disposed so as to face the scope 22 with the observation target portion 40 interposed therebetween, and the observation target portion 40 is transmitted with illumination. In this case, the direction of the reflecting surface is adjusted so that the optical axis of the quarter-wave plate disposed on the reflecting surface of the reflecting plate 51 forms an angle of 45 degrees with respect to the polarization direction of the polarizing element. If it does in this way, the illumination light radiate | emitted from the light source device 25 and passed through the light guide 25 will be maintained in a fixed polarization state via the polarizer arrange | positioned at an illumination window, and will be irradiated to the observation object site | part 40. FIG. The polarized light that has passed through the observation target part 40 is converted into circularly polarized light by the quarter-wave plate and enters the reflecting plate 51. The circularly polarized light reflected by the reflecting plate 51 is converted into polarized light having a polarization direction orthogonal to the polarization direction of the polarizer disposed in the illumination window by a quarter wavelength plate. That is, according to the endoscope observation apparatus of Example 3, the polarization direction is rotated 90 degrees by reciprocating the quarter wave plate provided with the polarized light transmitted through the observation target portion 40 on the reflection surface side. Thus, the observation target region 40 can be transmitted again.
Thereby, the light transmitted through the observation target part 40 reaches the image pickup surface of the image pickup element without being blocked by the polarizer arranged in the observation window. For this reason, according to the endoscope observation apparatus of Example 3, the running state of the blood vessel existing in the observation target portion 40 can be depicted more clearly while preventing halation.

  As described above, the endoscope observation apparatus of the present invention has the following features in addition to the invention described in the claims.

(1) An endoscopic observation apparatus according to any one of claims 1 to 4, wherein a bandpass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the illumination optical system. .

(2) The endoscope observation apparatus according to any one of claims 1 to 4, wherein a bandpass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the imaging optical system. .

(3) An endoscopic observation apparatus according to any one of claims 1 to 4, wherein a band-pass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the illumination optical system. .

(4) The endoscope observation apparatus according to any one of claims 1 to 4, wherein a band-pass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the imaging optical system. .

(5) The endoscope observation apparatus according to any one of claims 1 to 4, further comprising a reflecting plate that is inserted into a space opposite to the imaging optical system with the living body interposed therebetween.

(6) The endoscope observation apparatus according to (5), wherein a depolarization plate is added to the reflection plate.

(7) The endoscope observation apparatus according to (5), wherein a quarter wave plate is added to the reflection plate.

(8) An endoscope observation apparatus for identifying a specific part in a living body using a difference in spectral absorption characteristics of near infrared light of 1200 nm or more, which is 1200 nm or more and 2200 nm or less and near 1450 nm or 1900 nm. A light source unit that generates near-infrared light including a wavelength and near-infrared light that is not less than 1200 nm and not greater than 2200 nm and does not include any wavelength in the vicinity of 1450 nm and 1900 nm; and optically connected to the light source unit, An illumination unit that illuminates the different near-infrared light in a different illumination state with respect to the living body, and the near-red light of the living body is imaged on the imaging surface of the imaging element by imaging the different near-infrared light reflected by the living body. An imaging unit that acquires an outside image, and an image processing unit that processes the different near-infrared images acquired by the imaging unit. And the image processing unit is configured to perform contrast enhancement of a specific part in the living body based on the different near-infrared images captured in different illumination states. Endoscope observation device.

(9) An endoscope observation apparatus for identifying a specific part in a living body using a difference in spectral absorption characteristics of near infrared light of 1200 nm or more, which is 1200 nm or more and 2200 nm or less near 1450 nm or 1900 nm A plurality of light source units that generate near-infrared light including a wavelength, and a plurality of illumination units that are optically connected to the respective light source units and that illuminate the different near-infrared light in different illumination states with respect to a living body. An imaging unit that obtains a near-infrared image of the living body by forming images of the different near-infrared light reflected by the living body on an imaging surface of an imaging element, and the different near-fields acquired by the imaging unit. An image processing unit for processing an infrared image, and each of the image processing units is captured in a different illumination state. The endoscope observation apparatus characterized by being configured to based on the near-infrared image enhance a contrast of a particular site in vivo.

(10) The illumination unit and the imaging unit each have a polarizer, and further, the polarization direction of the polarized light that is reflected by the living body and incident on the polarizer in the imaging unit, and the polarization of the polarizer in the imaging unit The endoscope observation apparatus according to (8) or (9), wherein the direction is orthogonal to the direction.

(11) The light source unit and the illumination unit are connected via a light guide cable, and a polarizer in the illumination unit is rotatably disposed at a connection portion between the light guide cable and the illumination unit. The endoscope observation apparatus according to (10) above.

(12) The illumination unit and the imaging unit each have the polarizer on separate optical paths, and the polarizers are arranged so that the polarization directions thereof are orthogonal to each other (10) ) Endoscope observation apparatus.

(13) Of the illumination unit and the imaging unit, one has a half-wave plate and the polarizer, and the other has the polarizer on an optical path different from the one, and each of the polarizers Are arranged so that their polarization directions are the same, the endoscope observation apparatus according to (10) above.

(14) The illumination unit and the imaging unit share a ¼ wavelength plate and the polarizer, and the ¼ wavelength plate and the polarizer have an optical axis of the ¼ wavelength plate and the polarizer. The endoscope observation apparatus according to (10) above, wherein the endoscope observation apparatus is arranged so that an angle formed with the polarization direction is 45 °.

(15) Any one of the above (8) to (14), wherein a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on the optical path of the illumination unit. The endoscope observation apparatus described in 1.

(16) Any of the above (8) to (14), wherein a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on the optical path of the imaging unit The endoscope observation apparatus described in 1.

(17) Any of the above (8) to (14), wherein a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on the optical path of the illumination unit. The endoscope observation apparatus described in 1.

(18) Any one of (8) to (14) above, wherein a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on the optical path of the imaging unit. The endoscope observation apparatus described in 1.

(19) The endoscope according to any one of (8) to (14), wherein a band-pass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the illumination unit. Observation device.

(20) The endoscope according to any one of (8) to (14), wherein a band-pass filter having a transmission width of 1450 ± 100 nm is disposed on the optical path of the imaging unit. Observation device.

(21) The endoscope according to any one of (8) to (14), wherein a band-pass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the illumination unit. Observation device.

(22) The endoscope according to any one of (8) to (14) above, wherein a bandpass filter having a transmission width of 1900 ± 100 nm is disposed on the optical path of the imaging unit. Observation device.

(23) The endoscope observation apparatus according to any one of (8) to (14), further including a reflector that is inserted into a space opposite to the imaging unit with the living body interposed therebetween. .

(24) The endoscope observation apparatus according to (23), wherein a depolarization plate is added to the reflection plate.

(25) The endoscope observation apparatus according to (23), wherein a quarter wave plate is added to the reflection plate.

  The endoscope observation apparatus of the present invention is particularly useful in the medical field where it is required to accurately recognize the placement (running state) of blood vessels at a site to be operated and perform a minimally invasive surgical operation.

It is a graph which shows the spectral absorption characteristic of the fat and the blood vessel with respect to the light whose wavelength is 1000 nm or more. It is explanatory drawing which shows the state of the contrast of the observation image of the blood vessel using the endoscope observation apparatus of this invention, (a) is a wavelength range (near 1450 nm, 1900 nm vicinity) with the big change in the spectral absorption characteristic of a blood vessel and fat. (B) is a wavelength region (including wavelengths in the vicinity of 1450 nm or 1900 nm) where there is a large change in the spectral absorption characteristics of blood vessels and fats. The case where it observed using external light is each shown. It is explanatory drawing which shows schematic structure of the endoscope observation apparatus concerning Example 1 of this invention. It is a graph which shows the spectral transmittance characteristic of a band pass filter, (a) is a band pass filter which has the characteristic which permeate | transmits the wavelength range of 1450 nm +/- 100 nm, (b) has the characteristic which permeate | transmits the wavelength range of 1900 nm +/- 100 nm. Each bandpass filter is shown. 6 is an explanatory diagram illustrating an arrangement example of two polarizers provided at a distal end portion of an insertion portion 31 as halation preventing means in the endoscope observation apparatus of Embodiment 1. FIG. 10 is an explanatory diagram illustrating a schematic configuration of an endoscope observation apparatus according to a modification example of Example 1. FIG. It is explanatory drawing which shows one structural example of light source device 25 'in the endoscope observation apparatus of the modification of Example 1, (a) is a plane which shows the structure of the rotating disk arrange | positioned in the optical path of light source device 25'. FIG. 2B is a schematic configuration diagram showing an example of the arrangement of rotating disks in the light source device 25 ′. It is a graph which shows the spectral transmittance characteristic of the band pass filter which has the characteristic which permeate | transmits the wavelength band of 1700 nm +/- 100nm. 10 is a flowchart illustrating an example of a contrast enhancement processing procedure of an image of an observation target region 40 in an endoscope observation apparatus according to a modification of the first embodiment. It is explanatory drawing which shows the other structural example of the halation prevention means in the endoscope observation apparatus of this invention, (a) is a side view, (b) is a top view. It is an explanatory view showing still another configuration example of the halation prevention means applicable to the endoscope observation apparatus of the present invention, (a) is a plan view showing the arrangement relationship between the illumination window and the observation window and the halation prevention means, (b) is a side view of the halation preventing means in (a), and (c) is a plan view of (b). It is explanatory drawing which shows schematic structure of the endoscope observation apparatus concerning Example 2 of this invention. 12 is a flowchart illustrating an example of a contrast enhancement processing procedure of an image of an observation target region 40 in the endoscope observation apparatus according to the second embodiment.

Explanation of symbols

2B Abdominal part of living body 13 Band pass filter 15 Image sensor 18 Gastro-omentum 19 Blood vessel 22 Scope 23 Camera head 24 Video scope 25, 25 ′ Light source device 26 Image processing unit 27 TV monitor 31 Insertion unit 32 Grasping part 33 Eyepiece part 34 Light Guide cable 35 Light guide 36 Light guide connector 37 Lamp lighting control circuit 38 Lamp 39 Condensing lens 40 Observation target part 41 Objective lens 42 Relay optical system 43 Eyepiece 44 Imaging lens 45 Polarizing elements 45a and 45b Polarizer 45c 1/4 Wave plate 45c ′ Half-wave plate 51 Reflector plate 55 Second light source device 65 Second light guide cable 66 Illuminating sheath 66a Hand side operation section 66b Tip

Claims (8)

An endoscope observation apparatus for identifying a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more,
An illumination optical system for irradiating a living body with near-infrared light having a wavelength of 1200 nm to 2200 nm and having a wavelength near 1450 nm or 1900 nm;
An imaging optical system that obtains a near-infrared image of the living body by imaging the near-infrared light reflected by the living body on an imaging surface of an imaging device;
The illumination optical system and the imaging optical system each have a polarizer, and
An endoscope observation apparatus characterized in that a polarization direction of polarized light reflected by the living body and incident on a polarizer in the imaging optical system is orthogonal to a polarization direction of the polarizer in the imaging optical system . An endoscope observation apparatus for identifying a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more,
An illumination optical system for irradiating a living body with near-infrared light having a wavelength of 1200 nm to 2200 nm and having a wavelength near 1450 nm or 1900 nm;
An imaging optical system that obtains a near-infrared image of the living body by imaging the near-infrared light reflected by the living body on an imaging surface of an imaging device;
The illumination optical system and the imaging optical system each have a polarizer on separate optical paths,
Each of the polarizers is disposed so that the polarization directions are orthogonal to each other.
An endoscope observation apparatus characterized by that. An endoscope observation apparatus for identifying a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more,
An illumination optical system for irradiating a living body with near-infrared light having a wavelength of 1200 nm to 2200 nm and having a wavelength near 1450 nm or 1900 nm;
An imaging optical system that obtains a near-infrared image of the living body by imaging the near-infrared light reflected by the living body on an imaging surface of an imaging device;
Of the illumination optical system and the imaging optical system, one has a half-wave plate and a polarizer, and the other has a polarizer on an optical path different from the one,
Each of the polarizers is disposed so that the polarization directions are the same with each other.
An endoscope observation apparatus characterized by that. An endoscope observation apparatus for identifying a specific part in a living body using a difference in spectral absorption characteristics of near-infrared light of 1200 nm or more,
An illumination optical system for irradiating a living body with near-infrared light having a wavelength of 1200 nm to 2200 nm and having a wavelength near 1450 nm or 1900 nm;
An imaging optical system that obtains a near-infrared image of the living body by imaging the near-infrared light reflected by the living body on an imaging surface of an imaging device;
The illumination optical system and the imaging optical system share a ¼ wavelength plate and a polarizer,
The quarter-wave plate and the polarizer are arranged so that an angle formed by an optical axis of the quarter-wave plate and a polarization direction of the polarizer is 45 °.
An endoscope observation apparatus characterized by that. The internal vision according to any one of claims 1 to 4, wherein a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on the optical path of the illumination optical system. Mirror observation device. The internal vision according to any one of claims 1 to 4, wherein a bandpass filter having a transmission band of 1200 nm to 2200 nm and including 1450 nm is disposed on an optical path of the imaging optical system. Mirror observation device. The internal vision according to any one of claims 1 to 4, wherein a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on the optical path of the illumination optical system. Mirror observation device. The internal vision according to any one of claims 1 to 4, wherein a band pass filter having a transmission band of 1200 nm to 2200 nm and including 1900 nm is disposed on an optical path of the imaging optical system. Mirror observation device.

Images