JP2017064405A - Optical measuring apparatus and optical measuring method - Google Patents

Abstract

To identify a tissue in a subject more easily. An optical measurement apparatus includes a light source that emits near-infrared light, and transmission from the subject that is emitted from the subject by irradiation of the near-infrared light from the light source to the subject. A camera unit 30 that acquires image data by acquiring an image showing the intensity distribution of light or reflected light by two-dimensionally arranged pixels, and an analysis for identifying a tissue at each position of the subject 5 based on the image data And an output unit 50 that outputs information indicating the position of the tissue identified by the analysis unit 40 as an analysis result. [Selection] Figure 1

Description

  The present invention relates to an optical measurement apparatus and an optical measurement method for identifying a tissue of a subject.

  As a method for evaluating a tissue in a living body, for example, as in the invention described in Patent Document 1, from a contrast agent introduced into a target tissue by irradiating a living body with near-infrared light using a handheld probe. A method of performing evaluation by collecting light is known. In the invention described in Patent Document 1, three imaging devices that simultaneously acquire visible light data, a first set of near-infrared light data, and a second set of near-infrared light data are provided separately from the handheld probe. 1 shows a configuration in which information by near-infrared light acquired by a handheld probe and information acquired by three imaging devices are combined and output.

Special table 2013-514156 gazette

  However, in the method described in Patent Document 1, it is necessary to provide three imaging devices in addition to the handheld probe, and the configuration of the device is large and complicated, which may increase the cost for the realization. Moreover, in the method described in Patent Document 1, it is necessary to administer a contrast medium to a patient in advance, which causes a burden on the patient.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical measurement apparatus and an optical measurement method that can more easily identify a tissue in a subject.

An optical measurement apparatus according to one aspect of the present invention is
A near-infrared light source that emits near-infrared light; and
Image data is obtained by obtaining an image showing an intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the near-infrared light with the two-dimensionally arranged pixels. Imaging means to obtain;
Analysis means for identifying the tissue at each position of the subject based on the image data;
Output means for outputting information indicating the position of the tissue identified by the analysis means as an analysis result;
An optical measuring device comprising:
It is.

The optical measurement method according to one aspect of the present invention is as follows:
An image showing the intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the near-infrared light from the near-infrared light source is acquired by two-dimensionally arranged pixels. An imaging step of acquiring image data by
An analysis step for identifying a tissue at each position of the subject based on the image data acquired in the imaging step;
An output step of outputting information indicating the position of the tissue identified by the analysis step as an analysis result;
An optical measurement method comprising:
It is.

  ADVANTAGE OF THE INVENTION According to this invention, the optical measuring device and the optical measuring method which can identify the structure | tissue in a subject more simply are provided.

It is a schematic explanatory drawing which shows the structure of the optical measuring device which concerns on embodiment of this invention. It is a graph which shows the reflectance spectrum of the near-infrared band which concerns on the blood vessel, fat, and muscle. 3A is a visible light image of a finger of a hand, and FIG. 3B is an image corresponding to FIG. 3A created by measurement by the optical measuring device according to the embodiment of the present invention. is there. FIG. 4 (A) is a visible light image of a sample in which fat is placed on meat, and FIG. 4 (B) is a diagram of FIG. 4 (A) created by measurement by the optical measurement device according to the embodiment of the present invention. 4 (C) is a visible light image of a sample in which meat is further placed on the fat of the sample of FIG. 4 (A), and FIG. 4 (D) is an image of the present invention. FIG. 5 is an image corresponding to FIG. 4C created by measurement by the optical measurement device according to the embodiment. It is a graph which shows the result of having calculated | required the 2nd-order differential value of the absorbance spectrum obtained by measuring the cultured cell of a normal cell and two types of cancer cells (cancer cell 1, cancer cell 2). It is a graph which shows the transmission spectrum at the time of irradiating near infrared light with respect to 50 micrometers in thickness water. FIG. 7A is a pseudo RGB image of a blood vessel and its surroundings, and FIGS. 7B and 7C are calculations performed using reflectances of a plurality of wavelengths and displayed in gray scale. . It is a graph which shows the spectrum which converted the reflectance spectrum of the pig tissue into the standard normal variable. FIG. 9 (A) is a visible image relating to pig tissue, and FIG. 9 (B) is the same region as FIG. 9 (A), and the value of the standard normal variable of the reflectance spectrum at 1200 nm is divided by the value at 1290 nm. It is the image which showed distribution of the measured value. It is a graph which shows the 2nd derivative value of the reflectance absorbance spectrum of pig tissue.

[Description of Embodiment of Present Invention]
First, embodiments of the present invention will be listed and described.

  An optical measurement apparatus according to the present invention includes a near-infrared light source that emits near-infrared light, and transmitted light or reflection from the subject that is emitted from the subject by irradiation of the near-infrared light onto the subject. An imaging means for acquiring image data by acquiring an image showing an intensity distribution of light with pixels arranged in a two-dimensional manner, an analysis means for identifying a tissue at each position of the subject based on the image data, Output means for outputting information indicating the position of the tissue identified by the analysis means as an analysis result. Here, in the present application, “reflection” includes “diffuse reflection”.

  According to the above optical measurement apparatus, two images showing the intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the near-infrared light from the near-infrared light source onto the subject are displayed. After acquisition by the dimensionally arranged pixels, the tissue at each position of the subject is identified based on the image data. Therefore, the tissue can be identified without providing a plurality of imaging devices as in the conventional device and without performing prior drug administration to the subject. It becomes possible to identify.

  Further, the imaging means includes an intensity distribution of transmitted light or reflected light having a first wavelength included in the near infrared light, and a second wavelength included in the near infrared light unlike the first wavelength. Image data indicating the intensity distribution of transmitted light or reflected light of the first wavelength, and the analyzing means transmits the intensity distribution of transmitted light or reflected light of the first wavelength and transmitted light or reflected light of the second wavelength. The tissue of the subject can be identified based on the intensity distribution.

  By adopting a configuration in which the tissue of the subject is identified using the intensity distribution of transmitted light or reflected light of a plurality of wavelengths, for example, the influence of changes in the intensity of transmitted light or reflected light derived from unevenness of the subject And the tissue of the subject can be identified with higher accuracy.

  In addition, the near-infrared light irradiated to the subject may not include light in a wavelength band of 1380 nm to 1500 nm and 1880 nm to 2100 nm.

  The light in the wavelength band of wavelengths 1380 nm to 1500 nm and wavelengths 1880 nm to 2100 nm is light in which water absorbs a large proportion of energy. Therefore, the optical measurement apparatus having the above-described configuration can reduce the energy of light absorbed by the subject. Accordingly, it is possible to prevent a burn or the like from being generated by heating the subject.

  Further, the imaging means includes an intensity distribution of transmitted or reflected light having a first wavelength selected from wavelengths of 1000 nm to 1140 nm, and an intensity distribution of transmitted or reflected light having a second wavelength selected from wavelengths of 1240 nm to 1300 nm. , And the analysis unit may specify a position of a blood vessel in the subject based on the image data.

  With the above configuration, it is possible to more easily identify the position of the blood vessel in the tissue of the subject.

  Further, the imaging means acquires image data indicating an intensity distribution of transmitted light or reflected light having a wavelength selected from a wavelength of 1190 nm to 1220 nm and a wavelength of 1700 nm to 1780 nm, and the analyzing means is based on the image data, It can be set as the aspect which pinpoints the position of the tissue or arteriosclerosis part containing many lipids in a test object.

  By providing the above-described configuration, it is possible to more easily identify the position of the tissue containing a large amount of lipid or the arteriosclerotic portion among the tissues of the subject.

  The imaging means acquires image data indicating an intensity distribution of transmitted light or reflected light having a wavelength selected from a wavelength of 1490 nm to 1550 nm, a wavelength of 1610 nm to 1650 nm, and a wavelength of 1790 nm to 1820 nm, and the analyzing means includes the image data On the basis of the above, it is possible to determine the position of the lesion in the subject.

  By providing the above configuration, it becomes possible to more easily identify the position of the lesion in the tissue of the subject.

  Further, the imaging means includes an intensity distribution of transmitted light or reflected light having a first wavelength selected from wavelengths of 1000 nm to 1140 nm, and an intensity distribution of transmitted light or reflected light of a second wavelength selected from wavelengths of 1240 nm to 1300 nm. , And the imaging means obtains second image data indicating intensity distribution of transmitted light or reflected light having a wavelength selected from a wavelength of 1190 nm to 1220 nm and a wavelength of 1700 nm to 1780 nm, The analysis unit identifies a position of a tissue or arteriosclerotic portion containing a large amount of lipid in a blood vessel in the subject based on the image data acquired from the imaging unit, and the output unit is identified by the analysis unit. It can be set as the aspect which outputs the information which shows the performed structure | tissue.

  By providing the above configuration, it is possible to combine and output information related to the position of the tissue or arteriosclerotic portion containing a large amount of lipid in the blood vessel in the subject.

  The imaging means acquires image data indicating intensity distribution of transmitted light or reflected light having two or more wavelengths selected from a wavelength of 1180 nm to 1220 nm and a wavelength of 1270 nm to 1310 nm, and the analyzing means is based on the image data. The mode of specifying the position of the nerve in the subject can be adopted.

  With the above configuration, it is possible to more easily identify the position of the nerve in the tissue of the subject.

  Further, the imaging means acquires image data indicating an intensity distribution of transmitted or reflected light having two or more wavelengths selected from wavelengths 1280 nm to 1320 nm and wavelengths 1380 nm to 1420 nm, and the analyzing means is based on the image data. In this embodiment, the muscle position in the subject can be specified.

  By providing the above configuration, it is possible to more easily identify the position of the muscle in the tissue of the subject.

  The optical measurement method according to the present invention provides an image showing an intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the near-infrared light from the near-infrared light source onto the subject. An imaging step of acquiring image data by acquiring with two-dimensionally arranged pixels in the imaging means, and an analysis step of identifying a tissue at each position of the subject based on the image data acquired in the imaging step And an output step of outputting information indicating the position of the tissue identified by the analysis step as an analysis result.

  According to the above optical measurement method, two images showing the intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the near-infrared light from the near-infrared light source onto the subject are displayed. After acquisition by the dimensionally arranged pixels, the tissue at each position of the subject is identified based on the image data. Therefore, the tissue can be identified without providing a plurality of imaging devices as in the conventional device and without performing prior drug administration to the subject. It becomes possible to identify.

  In the imaging step, the transmitted light or reflected light intensity distribution of the first wavelength included in the near infrared light and the second wavelength included in the near infrared light different from the first wavelength. Image data indicating the intensity distribution of the transmitted light or reflected light of the first wavelength, and the intensity distribution of the transmitted light or reflected light of the first wavelength and the transmitted light or reflected light of the second wavelength in the analyzing step. The tissue of the subject can be identified based on the intensity distribution.

  By adopting a configuration in which the tissue of the subject is identified using the intensity distribution of transmitted light or reflected light of a plurality of wavelengths, for example, the influence of changes in the intensity of transmitted light or reflected light derived from unevenness of the subject And the tissue of the subject can be identified with higher accuracy.

[Details of the embodiment of the present invention]
Specific examples of the optical measuring device according to the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to the claim are included.

  FIG. 1 is a schematic explanatory diagram illustrating the configuration of an optical measurement apparatus 1 according to an embodiment of the present invention. The optical measurement apparatus 1 includes a light source 10 (near infrared light source), a filter unit 20, a camera unit 30 (imaging unit), an analysis unit 40 (analysis unit), and an output unit 50 (output unit). This optical measuring device 1 is a system for non-invasively observing an observation object. Examples of the subject 5 include a blood vessel inner wall.

  The light source 10 is a light source that emits light (near-infrared light) in a wavelength range of 1000 nm to 2500 nm. The light source 10 is more preferably capable of emitting light with a wider band. As the light source 10, for example, a halogen lamp, a xenon lamp, an SC (Supercontinuum) light source, or the like is preferably used.

  The light emitted from the light source 10 is collimated by the collimator lens 15 and then enters the filter unit 20.

  The filter unit 20 is arranged on the optical path of the light from the light source 10, receives the light emitted from the light source 10, and outputs only light having a specific wavelength to the subject 5. For the filter unit 20, a diffraction grating, a wavelength tunable filter, or the like is used. In FIG. 1, a filter wheel formed by including a plurality of filters 21 and 22 is shown as an example of the filter unit 20. By changing the positions of the filters 21 and 22 with respect to the incident light from the light source 10, light of a specific wavelength is taken out and output to a site to be observed of the subject 5. The control of the filter unit 20 may be configured to be performed by the analysis unit 40, for example, but may be configured to operate in conjunction with the camera unit 30. The filter unit 20 is not particularly limited as long as it is a wavelength selection element for selecting and imaging a specific wavelength. For example, instead of a filter wheel, an AOTF (Acousto-Optic Tunable Filter), an optical path selection device, Alternatively, a plurality of band pass filters or the like may be used.

  The camera unit 30 is means for inputting light diffusely reflected at the observation site of the subject 5 and acquiring an image related to the subject 5. Specifically, as an imaging unit that captures an image showing the intensity distribution of diffuse reflected light from the subject 5 by irradiating the subject 5 with near infrared light from the light source 10 and outputs image data. It has the function of. The camera unit 30 is provided with a light receiving surface 31 in which light receiving elements such as InGaAs or HgCdTe that convert light into current and output are two-dimensionally arranged. The image data acquired by the camera unit 30 is sent to the analysis unit 40.

  Note that the camera unit 30 may be a so-called hyperspectral camera that acquires a hyperspectral image having spectral information of light generated at each position of the observation target. In this case, instead of the filter unit 20, a spectroscope including a spectroscopic element such as a prism, grism, diffraction grating, or Fourier spectroscope is provided in the camera unit 30, and the input light is separated by wavelength and then received by the light receiving surface 31. By adopting a configuration for receiving light, a hyperspectral image of the subject 5 can be obtained.

  The analysis unit 40 has a function as analysis means for identifying the tissue at each position of the subject 5 based on the image data relating to the light received by the camera unit 30. An analysis method in the analysis unit 40 will be described later. The analysis result is sent from the analysis unit 40 to the output unit 50.

  The output unit 50 has a function of outputting information indicating the position of the tissue identified by the analysis unit 40 to the outside. The output unit 50 is configured by, for example, a monitor. In addition, when the information which shows the position of the structure | tissue in the analysis part 40 is output outside, you may have a function which performs the process etc. for highlighting a specific structure | tissue, for example.

  The optical measurement method using the optical measurement apparatus 1 is as follows. First, in the camera unit 30, the intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the near-infrared light from the light source 10 (near-infrared light source) to the subject is shown. Image data is acquired by acquiring an image with pixels arranged two-dimensionally (imaging step). Thereafter, based on the acquired image data, the analysis unit 40 identifies the tissue at each position of the subject (analysis step). And the information which shows the position of the structure | tissue identified in the analysis part 40 is output as an analysis result in the output part 50 (output step).

  The object of analysis by the optical measuring device 1 is, for example, a living tissue, specifically, blood vessels, muscles, fats, and the like. These tissues in a living body are difficult to distinguish from the surface. The optical measurement device 1 according to the present embodiment aims to identify the above-described living tissue for each tissue non-invasively.

  An analysis method in the analysis unit 40 based on image data acquired in the camera unit 30 of the optical measurement device 1 will be described. First, in the camera unit 30, the image data relating to the subject 5 relates to the reflectance at the first wavelength selected from the near-infrared light wavelength band and the second wavelength selected from the near-infrared light wavelength band. Information is acquired for each position of the subject 5. That is, at the time of measurement, near-infrared light having at least two types of wavelengths is irradiated from the light source 10 to the subject 5. Further, the camera unit 30 receives diffusely reflected light from the subject 5 with respect to near-infrared light of two types of wavelengths from the light source 10. Thereby, the information regarding the reflectance in two types of wavelengths can be acquired for each position of the subject 5. Note that the tissue can be identified by the optical measurement device 1 by analysis using near-infrared light of one type of wavelength. However, when near infrared light of two types of wavelengths is used, the accuracy is improved. In the following embodiments, measurement using near-infrared light of two types of wavelengths will be mainly described.

  In order to acquire the above information, the configuration may be such that near-infrared light irradiated to the subject 5 is switched one wavelength at a time and the camera unit 30 captures images twice. Further, it may be configured to acquire spectrum information corresponding to each position of the subject 5. In this case, it is possible to perform correction using spectral information and the like, so that tissue identification accuracy can be increased. Examples of the spectral information correction method include second-order differentiation and SNV (Standard Normal Variate) processing. When the second-order differential value with respect to the wavelength direction is used, information useful for tissue identification can be obtained without correcting offset or the like. Further, when correction is performed using SNV, it is possible to remove fluctuations in reflected light intensity due to non-uniformity of near-infrared light irradiated from the light source 10 to the subject, surface irregularities, and the like. The correction method is not limited to these.

  In addition, when it is set as the structure which acquires the spectrum information corresponding to each position in the optical measuring device 1, it is preferable to set it as the structure which uses the camera part 30 as a hyperspectral camera, and acquires a hyperspectral image.

  The above two types of wavelengths are a first wavelength corresponding to an absorption peak in an absorption spectrum related to a tissue to be identified and a second wavelength that is different from the absorption peak. When only the reflectance relating to the light of one kind of wavelength is used as in the case where only the reflectance of the light of the first wavelength is used, the intensity of the diffuse reflected light derived from the unevenness of the subject 5 and others is changed. This is because it cannot be considered. Therefore, the reflectance in the light of the second wavelength is also used. Since the width of the absorption peak is generally within 30 nm, it is preferable that the second wavelength is separated by 30 nm or more with respect to the first wavelength. Note that the difference between the first wavelength and the second wavelength is preferably 200 nm or less. When this difference is larger than 200 nm, only one of the reflectance in the light of the first wavelength and the reflectance in the light of the second wavelength may be affected by other effects such as scattering.

  The analysis unit 40 identifies the tissue based on the reflectance of the first wavelength light and the reflectance of the second wavelength light. Specifically, the classification is performed based on whether or not the ratio of the reflectance of the first wavelength light to the reflectance of the second wavelength light is within a predetermined range.

  Further description will be given with reference to an example of analysis using the optical measuring device 1. As an example, an incision is made in a mammal, the reflectance spectrum in the near-infrared band related to blood vessels, fats and muscles is measured, and the result of calculating the value obtained by dividing the reflectance of each wavelength by the standard deviation of all wavelengths is shown in FIG. It is shown in 2.

  According to the graph shown in FIG. 2, it can be seen that the blood vessel can be used for identification because the reflectance is lower than that of the surrounding muscle and adipose tissue in the wavelength band of 1000 nm to 1140 nm. Further, in the wavelength band 1240 nm to 1300 nm, there is no strong absorption peak in any living tissue (a gentle curve), so that it can be used as a reference reflected light intensity with respect to the reflected light intensity in the wavelength band 1000 nm to 1140 nm. That is, when the first wavelength is selected from the wavelength band 1000 nm to 1140 nm and the second wavelength is selected from the wavelength band 1240 nm to 1300 nm, the blood vessel can be suitably identified.

  Further, since fat has a characteristic absorption peak (downward peak) in the wavelength band 1190 nm to 1220 nm or 1700 nm to 1780 nm, the fat portion can be specified by using the reflected light intensity in this wavelength band. . By specifying the fat portion, it is possible to specify a tissue or an arteriosclerotic portion containing a large amount of lipid. The tissue rich in lipids refers to a tissue stained with Oil Red O staining. In addition, regarding a muscle or the like, it is possible to identify a region that is not identified as a blood vessel or fat as a muscle or the like.

  Next, the result of observing the blood vessels of the fingers of the hand using the optical measurement apparatus 1 according to the present embodiment and a visible light image are shown in FIG. FIG. 3A is a normal visible light image, and FIG. 3B is obtained by using the optical measurement apparatus 1 to obtain a reflection spectrum in a wavelength band including a wavelength of 1110 nm and a wavelength of 1260 nm, and performing SNV processing. After that, the ratio of the reflectance at the wavelength of 1110 nm to the reflectance at the wavelength of 1260 nm is obtained for each position, and the result is imaged in gray scale. In the visible light image of FIG. 3A, the position of the blood vessel of the finger cannot be clearly determined. On the other hand, in the image of FIG. 3B, the position of the blood vessel is displayed in white. That is, it was confirmed that by using the optical measuring device 1, blood vessels that cannot be seen from the surface under the skin can be clearly displayed.

  FIG. 4 is a result of observing a sample in which fat is placed on meat using the optical measurement apparatus 1 according to the present embodiment and a sample in which the fat on meat is coated with meat, and a visible light image. 4 (A) (a sample in which fat is placed on meat) and FIG. 4 (C) (a sample in which fat is coated with meat) are normal visible light images, and FIG. 4 (B) (FIG. 4). (Image corresponding to (A)) and FIG. 4 (D) (image corresponding to FIG. 4 (C)) are obtained after obtaining a reflection spectrum in a wavelength band including the wavelength 1210 nm using the optical measuring device 1. The second order derivative of the reflected light intensity at is obtained, and the result is imaged in gray scale. In FIGS. 4B and 4D, it can be seen that fat can be clearly identified and imaged from surrounding muscles. In particular, according to FIG. 4C and FIG. 4D, the optical measurement apparatus 1 according to the present embodiment is also used for a hidden tissue that is difficult to identify with visible light because it is covered with some tissue or the like. It can be confirmed that the measurement used is effective.

  Furthermore, in the optical measuring device 1 according to the present embodiment, it is also possible to specify a lesion portion when there is a certain lesion in the tissue by changing the wavelength used for analysis. Examples of the lesion part include a cancerous part. Here, the result of obtaining the second derivative of the absorbance spectrum obtained by measuring the cultured cells of normal cells and two types of cancer cells (cancer cell 1 and cancer cell 2) using the optical measuring device 1 is shown in FIG. As shown in FIG. According to FIG. 5, in each of the wavelength band 1490 nm to 1550 nm, the wavelength band 1610 nm to 1650 nm, and the wavelength band 1790 nm to 1820 nm, the cancer cell and the normal cell have different absorbance second-order differential values, and both types of cancer cells It was confirmed to have a larger or smaller value than normal cells. Therefore, after obtaining the reflection spectrum in these wavelength bands, calculating the absorption spectrum, and obtaining the second-order absorbance value, this can be used to identify and display the lesion such as the diseased part of the cancer. Is possible.

  In FIG. 6, the transmission spectrum at the time of irradiating near infrared light with respect to 50 micrometers in thickness water is shown. According to FIG. 6, it can be seen that the transmittance is high because the transmittance is greatly reduced in the wavelength bands of 1380 nm to 1500 nm and 1880 nm to 2100 nm. Based on the graph of FIG. 6, when a light source having a constant output regardless of the wavelength is used as the light source 10 of the optical measuring device 1, the energy with which light having a wavelength band of 1000 nm to 2400 nm is absorbed by water having a thickness of 50 μm. Of this, 58% is due to the absorption of light in the above wavelength band. Therefore, the energy of the light absorbed by the subject 5 can be reduced by removing the light in the above wavelength band from the light irradiated to the subject 5. Therefore, it is possible to prevent a burn or the like from being generated when the subject 5 is heated.

  In addition, when performing the tissue identification of a living body, the above methods can be combined. At this time, in order to identify a specific tissue more clearly, a combination of reflectances at a plurality of wavelengths may be weighted.

In FIG. 7, the example which performed the analysis which concerns on the blood vessel and its periphery is shown. FIG. 7A is a pseudo RGB image (corresponding to a visible light image) of a blood vessel and its surroundings. The blood vessel exists in region A1 in FIG. FIG. 7B and FIG. 7C show calculations using a reflectance of a plurality of wavelengths and are displayed in gray scale. Specifically, FIG. 7B shows a reflectance spectrum at a wavelength of 1658 nm, a wavelength of 1727 nm, and a wavelength of 1796 nm after obtaining a reflection spectrum in the wavelength band of 1000 nm to 2300 nm using the optical measurement apparatus 1 and performing SNV processing. Obtained for each position, the following formula (1):
[(Reflectance at wavelength 1658 nm + Reflectivity at wavelength 1796 nm) / 2−Reflectivity at wavelength 1727 nm] / 2 (1)
And the result is imaged in grayscale. It is possible to calculate the depth of the fat absorption peak (1727 nm) in the reflectance spectrum by the above formula (1), and it is possible to identify the region where fat mainly exists, that is, the region A2 in FIG. It is a mathematical formula. However, in FIG. 7B, there is a problem that it is difficult to identify the region A1 indicating the blood vessel.

On the other hand, in FIG. 7C, the following formula (2) including a term corresponding to the absorption of hemoglobin and a coefficient for adjusting the degree of enhancement with respect to the above formula (1):
5 × (Reflectance at wavelength 1286 nm / Reflectivity at wavelength 1109 nm) × [(Reflectance at wavelength 1658 nm + Reflectivity at wavelength 1796 nm) / 2−Reflectance at wavelength 1727 nm] / 2 (2)
And the results were imaged in grayscale. In the above formula (2), 5 is a coefficient for adjusting the enhancement degree, and (reflectance at wavelength 1286 nm / reflectivity at wavelength 1109 nm) is a term for enhancing absorption of hemoglobin. As a result, in FIG. 7C, since the region A1 corresponding to the blood vessel can be emphasized with respect to the region A2 corresponding to fat, the tissue containing a large amount of lipid in the blood vessel, that is, the arteriosclerotic portion is more clearly shown Can be identified.

  In this way, when there is a tissue to be identified in particular, it is preferable to perform an operation using reflectances of a plurality of wavelengths so that it can be emphasized. In the example shown in FIG. 7, reflectances at a wavelength of 1658 nm, a wavelength of 1727 nm, and a wavelength of 1796 nm are used. As described above, in the analysis example illustrated in FIG. 7, the two wavelengths of the wavelength 1658 nm and the wavelength 1727 nm are used as the first wavelength, and the wavelength 1796 nm is used as the second wavelength. When performing analysis of the blood vessel and its surroundings as shown in FIG. 7, the wavelength selected from the wavelength band 1650 nm to 1670 nm including the wavelength 1658 nm and the wavelength selected from the wavelength band 1720 nm to 1740 nm including the wavelength 1727 nm The wavelength of 1 can be used, and the reflectance at the first wavelength can be combined for use in the analysis. In addition, a wavelength selected from a wavelength band of 1790 nm to 1810 nm including a wavelength of 1796 nm can be used as a second wavelength, and reflectance at the second wavelength can be used for analysis.

  FIG. 8 shows a graph of a spectrum obtained by converting the reflectance spectrum of pig tissue into a standard normal variable. According to FIG. 8, the spectra at wavelengths of 1180 nm to 1220 nm and wavelengths of 1270 nm to 1310 nm are different among nerves, muscles, fats, and blood vessel walls. Therefore, it is possible to image nerves by selecting the above wavelength band. Further, FIG. 9 shows the result of showing the distribution of values obtained by dividing the standard normal variable of the reflectance spectrum at 1200 nm by the value at 1290 nm. FIG. 9 (A) is a visible image relating to pig tissue, and FIG. 9 (B) is the same region as FIG. 9 (A), and the value of the standard normal variable of the reflectance spectrum at 1200 nm is divided by the value at 1290 nm. It is the image which showed distribution of the measured value. As shown in FIG. 9, the position of the nerve can be specified by imaging the numerical value obtained using the standard normal variable.

  Similarly, a graph of the second derivative of the reflectance absorbance spectrum of pig tissue is shown in FIG. According to FIG. 10, the secondary differential values at wavelengths of 1280 nm to 1320 nm and wavelengths of 1380 nm to 1420 nm are different between muscle and other tissues. Therefore, it is possible to specify the position of the muscle by imaging the value calculated using the secondary differential value and other wavelengths with no difference between tissues as a reference.

  The output unit 50 may output the calculation result for each position of the subject 5 as an image when the result of the analysis by the analysis unit 40 is output. In addition, for example, when a visible light image of the subject 5 is captured by another device, an image of a calculation result by the optical measurement device 1 and a visible light image captured by another device are arranged side by side or A configuration in which the images are displayed in a superimposed manner may be used. As described above, the method of outputting the calculation result by the output unit 50 can be changed as appropriate.

  As described above, according to the optical measurement device 1 and the optical measurement method using the optical measurement device 1 described above, the subject 5 emitted from the subject by irradiation of the near-infrared light from the light source 10 onto the subject is used. After the image showing the intensity distribution of the reflected light is acquired by the pixels two-dimensionally arranged on the light receiving surface 31, the analysis unit 40 identifies the tissue at each position of the subject 5 based on the image data, and as a result Is output from the output unit 50. Therefore, the tissue can be identified without providing a plurality of imaging devices as in the conventional device and without performing prior drug administration to the subject. It becomes possible to identify. In particular, when the configuration from the imaging to the output of the subject 5 is executed in real time, for example, a doctor can perform treatment while confirming the type of the internal tissue of the subject 5 during surgery.

  In addition, as described above, by selecting the wavelength used for tissue identification, information indicating the position of the blood vessel, information indicating the position of the tissue or arteriosclerotic portion containing a large amount of lipid, and information indicating the position of the lesion are obtained. It can be obtained. Further, it is possible to obtain information indicating the position of the muscle based on these pieces of information. In this case, by outputting a combination of a plurality of information from the output unit 50, the user of the optical measurement device 1 can recognize the identification of a plurality of types of tissues at a time.

  Further, the near-infrared light irradiated to the subject 5 in the optical measurement apparatus 1 does not include light in the wavelength bands of wavelengths 1380 nm to 1500 nm and wavelengths 1880 nm to 2100 nm, so that light absorbed by the subject is absorbed. Energy can be reduced. Accordingly, it is possible to prevent a burn or the like from being generated by heating the subject.

  The optical measuring device according to the present invention is not limited to the above embodiment. For example, the arrangement of the light source 10, the filter unit 20, the camera unit 30, the analysis unit 40, and the output unit 50 in the optical measurement apparatus 1 is not particularly limited as in the above embodiment. For example, in the above-described embodiment, an example in which the light source 10 and the camera unit 30 are arranged on the same side with respect to the subject 5 has been described, but the light source 10 and the camera unit 30 are different from each other with respect to the subject 5. It may be arranged on the side. In this case, the camera unit 30 can be configured to image the transmitted light after the near infrared light from the light source 10 passes through the subject 5. In the above-described embodiment, the diffuse reflection light is imaged by the camera unit 30 and the calculation is performed using the reflectance. However, when the transmitted light is imaged by the camera unit 30, the intensity distribution of the transmitted light is used. It is preferred to identify the tissue using absorption or transmission.

  Moreover, the filter part 20 should just be arrange | positioned in either on the optical path between the light source 10 and the camera part 30. FIG. However, when the light source 10 side of the subject 5 is arranged, that is, in the arrangement shown in FIG. 1, the wavelength of light irradiated on the subject 5 can be limited. The amount of light can be reduced.

  DESCRIPTION OF SYMBOLS 1 ... Optical measuring device, 10 ... Light source, 20 ... Filter part, 30 ... Camera part, 40 ... Analysis part, 50 ... Output part.

Claims (11)

A near-infrared light source that emits near-infrared light; and
Image data is obtained by obtaining an image showing an intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the near-infrared light with the two-dimensionally arranged pixels. Imaging means to obtain;
Analysis means for identifying the tissue at each position of the subject based on the image data;
Output means for outputting information indicating the position of the tissue identified by the analysis means as an analysis result;
An optical measuring device. The imaging means includes an intensity distribution of transmitted light or reflected light having a first wavelength included in the near-infrared light, and transmission of a second wavelength included in the near-infrared light, which is different from the first wavelength. Obtaining image data indicating the intensity distribution of light or reflected light,
The analysis unit identifies the tissue of the subject based on the intensity distribution of the transmitted light or reflected light of the first wavelength and the intensity distribution of the transmitted light or reflected light of the second wavelength. The optical measuring device described.   The optical measurement apparatus according to claim 1, wherein the near-infrared light irradiated to the subject does not include light in a wavelength band of a wavelength of 1380 nm to 1500 nm and a wavelength of 1880 nm to 2100 nm. The imaging means includes an intensity distribution of transmitted light or reflected light having a first wavelength selected from wavelengths of 1000 nm to 1140 nm, and an intensity distribution of transmitted light or reflected light of a second wavelength selected from wavelengths of 1240 nm to 1300 nm. Get the image data
The optical measurement apparatus according to claim 1, wherein the analysis unit specifies a position of a blood vessel in the subject based on the image data. The imaging means acquires image data indicating an intensity distribution of transmitted light or reflected light having a wavelength selected from a wavelength of 1190 nm to 1220 nm and a wavelength of 1700 nm to 1780 nm,
The optical measurement apparatus according to any one of claims 1 to 3, wherein the analysis unit specifies a position of a tissue or an arteriosclerotic portion containing a large amount of lipid in the subject based on the image data. The imaging means acquires image data indicating the intensity distribution of transmitted or reflected light having a wavelength selected from a wavelength of 1490 nm to 1550 nm, a wavelength of 1610 nm to 1650 nm, and a wavelength of 1790 nm to 1820 nm,
The optical measurement apparatus according to claim 1, wherein the analysis unit specifies a position of a lesion in the subject based on the image data. The imaging means includes an intensity distribution of transmitted light or reflected light having a first wavelength selected from wavelengths of 1000 nm to 1140 nm, and an intensity distribution of transmitted light or reflected light of a second wavelength selected from wavelengths of 1240 nm to 1300 nm. First image data shown, and the imaging means acquires second image data showing intensity distribution of transmitted light or reflected light having a wavelength selected from a wavelength of 1190 nm to 1220 nm and a wavelength of 1700 nm to 1780 nm,
The analysis unit specifies a position of a tissue or arteriosclerosis portion containing a large amount of lipid in a blood vessel in the subject based on the image data acquired from the imaging unit,
The optical measurement apparatus according to claim 1, wherein the output unit outputs information indicating the tissue identified by the analysis unit. The imaging means obtains image data indicating intensity distribution of transmitted light or reflected light having two or more wavelengths selected from wavelengths 1180 nm to 1220 nm and wavelengths 1270 nm to 1310 nm,
The optical measurement apparatus according to claim 1, wherein the analysis unit specifies a position of a nerve in the subject based on the image data. The imaging means acquires image data indicating intensity distribution of transmitted light or reflected light of two or more wavelengths selected from wavelengths 1280 nm to 1320 nm and wavelengths 1380 nm to 1420 nm,
The optical measurement apparatus according to claim 1, wherein the analysis unit specifies a position of a muscle in the subject based on the image data. Pixels that are two-dimensionally arranged in the imaging means for an image showing an intensity distribution of transmitted light or reflected light from the subject emitted from the subject by irradiation of the subject with near-infrared light from a near-infrared light source An imaging step of acquiring image data by acquiring
An analysis step for identifying a tissue at each position of the subject based on the image data acquired in the imaging step;
An output step of outputting information indicating the position of the tissue identified by the analysis step as an analysis result;
An optical measurement method comprising: In the imaging step, the transmitted light or reflected light intensity distribution of the first wavelength included in the near-infrared light and the transmission of the second wavelength included in the near-infrared light different from the first wavelength. Obtaining image data indicating the intensity distribution of light or reflected light,
11. The tissue of the subject is identified in the analysis step based on an intensity distribution of transmitted light or reflected light of the first wavelength and an intensity distribution of transmitted light or reflected light of the second wavelength. The optical measurement method described.