JP2014000246A - Blood vessel visualization device and blood vessel visualization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a blood vessel visualization device and a blood vessel visualization method which enable a user to correctly distinguish between veins and arteries in a blood vessel part.SOLUTION: A near-infrared image analyzing and processing unit (5) distinguishes between pixels of an artery part and pixels of a vein part according to magnitude correlation between a predetermined value and a differential value between the maximum luminance value and the minimum luminance value of each pixel in blood vessel pixels extracted from near-infrared image data of a living body (2). An image data composite processing unit (7) creates a composite visible image data of the living body from generated artery part image data and vein part image data. An image data display unit (8) displays an image of the composite image data.

Description

  The present invention relates to a blood vessel visualization device and a blood vessel visualization method that can easily realize the discrimination between a vein and an artery by imaging a blood vessel of a living body, and can monitor the blood flow state of the artery.

  In order to perform intravenous injection or drip on a person, it is necessary to first confirm the exact position of the vein for puncturing the injection needle or catheter. For patients with renal insufficiency who cannot purify blood with the kidneys, when performing hemodialysis at home, the patient himself or his / her caregiver performs a procedure to pierce the blood vessels of the arms with blood vessels. It is necessary to confirm the exact position of the.

  Furthermore, if hemodialysis is repeated, the artery is gradually clogged, and eventually there is a high possibility that the artery will become occluded. Therefore, it is necessary to grasp and manage the blood flow state of the artery.

  In order to satisfy these requirements, conventionally, the near infrared ray is irradiated to a site to be visualized, and the reflected light is photographed using a near infrared CCD camera or the like, so that the depth of 3 to 7 mm from the skin. There is an apparatus for imaging and visualizing veins (see, for example, Patent Document 1).

JP 2011-160891 A

However, the prior art has the following problems.
With the conventional device as shown in Patent Document 1, it is possible to visualize blood vessels close to the surface of a living body, but it is very difficult to visualize deep blood vessels.

  Further, such a conventional device is visualized by detecting the intensity of reflected light from the surface of the living body. For this reason, even if it is a thick blood vessel, if it is in the deep layer portion, the reflected light is weakened due to the influence of the living tissue, so that it appears black and thin. As a result, the thickness of the blood vessel visualized and displayed does not match the actual thickness of the blood vessel, and furthermore, it is difficult to discriminate between the vein and the artery based on the contrast of the captured image.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a blood vessel visualization device and a blood vessel visualization method capable of accurately identifying a vein and an artery of a blood vessel part. .

  The blood vessel visualization device according to the present invention includes a first light source that irradiates a living body with near-infrared light, near-infrared light reflected or transmitted from the living body by irradiating the living body with near-infrared light, and visible to the living body. A camera that captures visible light reflected or transmitted from a living body by being irradiated with light, and a near-infrared image data generation unit that generates near-infrared image data of the living body based on near-infrared light captured by the camera; A visible image data generation unit that generates visible image data of a living body based on visible light captured by the camera, and a plurality of near infrared image data generated by the near infrared image data generation unit during a pulsation period of a blood vessel. Calculates the average brightness value, maximum brightness value, and minimum brightness value for each pixel, and specifies the threshold for blood vessel discrimination based on the frequency distribution of the average brightness value calculated for each pixel. And the average brightness is The pixel below the value is extracted as a blood vessel part, and the difference value between the highest luminance value and the lowest luminance value calculated in the period of the blood vessel pulsation period is calculated for each pixel extracted as the blood vessel part, and the calculated difference value Based on a comparison with a predetermined value that is defined in advance, vein image data is generated that makes it possible to identify a blood vessel pixel whose difference value is less than the predetermined value as a vein portion, and a blood vessel whose difference value is greater than or equal to the predetermined value A near-infrared image analysis / processing unit that generates arterial image data that enables identification of a part of pixels as an arterial part, and a venous image data and an arterial image data generated by the near-infrared image analysis / processing unit, An image data composition processing unit that generates composite image data that can identify a living body, a vein part, and an arterial part by synthesizing the visible image data generated by the visible image data generation unit, and image data composition Those comprising an image data display unit for displaying the synthesized image data processing section is generated.

  A blood vessel visualization method according to the present invention is a blood vessel visualization method executed by a blood vessel visualization device to identify and display a vein part and an arterial part in a living body by processing an imaging signal from a camera, and is close to the living body. Imaging that captures a near-infrared light signal reflected or transmitted from a living body by being irradiated with infrared light and a visible light signal reflected or transmitted from the living body by being irradiated with visible light as an imaging signal by the camera. A near-infrared image data generation step for generating near-infrared image data of the living body based on the near-infrared light signal imaged in the imaging step, and a visible image of the living body based on the visible light signal imaged in the imaging step A plurality of near-infrared image data generated in the near-infrared image data generation step during the period of the pulsation cycle of the blood vessel, A calculation step of calculating a luminance average value, a luminance maximum value, and a luminance minimum value for each of the pixels constituting the pixel, and a blood vessel based on the frequency distribution of the luminance average value calculated for each pixel by the calculation step A blood vessel part extraction step that identifies a threshold value for discrimination and extracts pixels whose average luminance value is less than or equal to the threshold value as a blood vessel part, and the highest luminance value and the lowest luminance value calculated by the calculation step during the pulsation period of the blood vessel Is calculated for each pixel extracted as a blood vessel part, and based on a comparison between the calculated difference value and a predetermined value defined in advance, pixels of the blood vessel part whose difference value is less than the predetermined value are Generating vein part image data that can be identified as a part, and generating arterial part image data that can identify a blood vessel part pixel having a difference value equal to or greater than a predetermined value as an arterial part By combining the venous part image data and the arterial part image data generated in the part identifying step, the arterial part / vein part identifying step, and the visible image data generated in the visible image data generating step, And an image data composition processing step for generating composite image data capable of identifying the arterial portion, and an image data display step for displaying the composite image data generated in the image data composition processing step.

  According to the blood vessel visualization device and the blood vessel visualization method of the present invention, for blood vessel pixels extracted from near-infrared image data, depending on the magnitude relationship between the difference value between the maximum luminance value and the minimum luminance value of each pixel and a predetermined value. The blood vessel visualization device and the blood vessel visualization method can be obtained that can accurately identify the vein and the artery of the blood vessel by displaying the image by dividing the pixel into the pixel of the artery and the pixel of the vein.

It is the block diagram which showed the function structure of the blood vessel visualization apparatus in Embodiment 1 of this invention. It is the schematic diagram which showed the picked-up image of the near infrared image data which the near infrared image data generation part in Embodiment 1 of this invention produced | generated. It is explanatory drawing when the near-infrared image analysis and process part in Embodiment 1 of this invention calculates | requires the threshold value of blood-vessel discrimination from the peak of a luminance value histogram. It is the block diagram which showed the function structure of the blood vessel visualization apparatus provided with the artery occlusion monitoring function in Embodiment 2 of this invention. It is explanatory drawing about the function and operation | movement of the blood vessel visualization apparatus provided with the artery occlusion monitoring function in Embodiment 2 of this invention.

  Hereinafter, preferred embodiments of a blood vessel visualization device and a blood vessel visualization method of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
<1. Configuration of blood vessel visualization device>
FIG. 1 is a block diagram showing a functional configuration of the blood vessel visualization device according to Embodiment 1 of the present invention. The blood vessel visualization apparatus in FIG. 1 includes a near infrared LED array 1, a camera 3 for imaging a living body 2, a near infrared image data generation unit 4, a near infrared image analysis / processing unit 5, and a visible image data generation unit 6. The image data composition processing unit 7 and the image data display unit 8 are provided.

  The near infrared LED array 1 irradiates the living body 2 with near infrared light as a first light source. Furthermore, natural light or a fluorescent lamp (not shown) irradiates the living body 2 with visible light as a second light source. The camera 3 receives reflected (or transmitted) light of light irradiated on the living body 2 from the first light source and the second light source, and outputs a near-infrared imaging signal and a visible imaging signal. The second light source may be provided in the blood vessel visualization device or may be outside the blood vessel visualization device.

  The near-infrared image data generation unit 4 quantizes the near-infrared imaging signal output from the camera 3 and generates near-infrared image data of a digital signal. The near-infrared image analysis / processing unit 5 analyzes the near-infrared image data generated by the near-infrared image data generation unit 4, performs pixel processing of the blood vessel portion, and obtains the vein portion image data and the artery portion image data. Generate.

  On the other hand, the visible image data generation unit 6 quantizes the visible imaging signal output from the camera 3 to generate visible image data of a digital signal. The image data synthesis processing unit 7 synthesizes the vein image data and the arterial image data generated by the near-infrared image analysis / processing unit 5 and the visible image data generated by the visible image data generation unit 6 to generate a synthesized image. Generate data. The image data display unit 8 displays the synthesized image data generated by the image data synthesis processing unit 7 as an image.

  Next, detailed configurations inside the camera 3 and the near-infrared image analysis / processing unit 5 will be described. First, the camera 3 includes a lens 31, a dichroic mirror 32, an IR image sensor 33, and a visible image sensor 34.

  The lens 31 collects reflected (or transmitted) light of the light irradiated on the living body 2 from the first light source and the second light source. The dichroic mirror 32 reflects light in the near-infrared wavelength band (800 to 950 nm) in the direction of 90 ° and allows visible (700 nm or less) light to pass through.

  The IR imaging element 33 images near-infrared light reflected by the dichroic mirror 32. The visible imaging element 34 images the visible light that has passed through the dichroic mirror 32.

  Next, the near-infrared image analysis / processing unit 5 includes a luminance average value generation unit 51, a luminance maximum value detection / storage unit 52, a luminance minimum value detection / storage unit 53, a luminance histogram generation / blood vessel discrimination threshold setting unit 54, And a composite image data setting unit 55.

  The luminance average value generation unit 51 calculates the average luminance value (luminance average value) of each pixel of the plurality of near infrared image data generated by the near infrared image data generation unit 4 in a period corresponding to the pulsation cycle of the blood vessel. calculate. The luminance maximum value detection / storage unit 52 detects and stores the maximum luminance value (luminance maximum value) of each pixel of the plurality of near-infrared image data. The minimum luminance value detection / storage unit 53 detects and stores the minimum luminance value (minimum luminance value) of each pixel of the plurality of near-infrared image data.

  The luminance histogram generation / blood vessel discrimination threshold setting unit 54 generates a histogram of the average luminance value of each pixel generated by the average luminance value generation unit 51, and the first and second peaks located on the high luminance side in this luminance distribution. A luminance value is extracted to set a threshold value for discriminating between a blood vessel portion including a vein and an artery and other portions. The composite image data setting unit 55 sets pixels to be combined with the visible image as the blood vessel part based on the threshold value for determining the blood vessel part.

<2. Operation of blood vessel visualization device>
Next, the operation of each functional unit of the blood vessel visualization device according to the first embodiment will be described in detail with reference to FIG. 1, FIG. 2, and FIG.

  Here, FIG. 2 is a schematic diagram showing a captured image of near-infrared image data generated by the near-infrared image data generation unit 4 according to Embodiment 1 of the present invention. 2A shows a schematic diagram of near-infrared image data generated by the near-infrared image data generation unit 4, and FIG. 2B shows a near-infrared image analysis / processing unit 5 that is near-red. The schematic diagram at the time of decomposing | disassembling external image data by a pixel is shown.

  FIG. 3 is an explanatory diagram when the near-infrared image analysis / processing unit 5 according to Embodiment 1 of the present invention obtains the blood vessel discrimination threshold value from the peak of the luminance value histogram.

  A near-infrared LED array 1 that is a first light source includes a plurality of near-infrared LEDs arranged, and irradiates near-infrared light to a site where a blood vessel of a living body 2 is desired to be visualized. The number of near-infrared LEDs arranged in the near-infrared LED array 1 may be determined according to the area of the site where the blood vessel of the living body 2 is desired to be visualized.

  The range of the emission wavelength (peak wavelength) of the near-infrared LED may be in the range of 700 nm to 1000 nm, which is called a so-called biological window. In particular, the wavelength is shorter than 900 nm at which light absorption due to moisture as a main component of the living body occurs. The range of 820 nm to 880 nm is preferable because it can penetrate deeper into the living body and the absorption of blood from the artery is large.

  Moreover, you may use the near-infrared laser whose light emission wavelength is the same wavelength band as near-infrared LED instead of near-infrared LED.

  Near-infrared light irradiated on the living body 2 by the near-infrared LED array 1 is absorbed by hemoglobin which is the main component of blood flowing through the blood vessels. Further, the near-infrared light again emerges from the skin as reflected light or transmitted light on the surface of the living body while being absorbed and scattered in the living body.

  Then, when the reflected light or transmitted light that has come out on the surface of the living body is imaged using an imaging device (for example, a CCD or CMOS sensor) that is highly sensitive to near infrared rays, the blood vessel portion is connected to a living body portion other than the blood vessel portion. An image having relatively low luminance can be obtained.

  In this image, the blood vessel part is photographed in such a manner that it becomes low brightness and floats, but the surface of the living body being visually observed is not photographed clearly. Therefore, the camera 3 in the first embodiment outputs two types of images, a near-infrared image and a visible image.

  That is, the camera 3 reflects the reflected light (indicated by the broken line shown in FIG. 1) when the living body 2 is irradiated with near-infrared light by the near-infrared LED array that is the first light source in order to photograph the blood vessel inside the living body. (Corresponding to an arrow) is collected by the lens 31.

  Further, the camera 3 captures reflected light (indicated by the dotted line shown in FIG. 1) when the living body 2 is irradiated with visible light such as natural light or a fluorescent lamp as a second light source in order to photograph the surface of the living body being viewed. Similarly, the light is condensed by the lens 31.

  The camera 3 reflects the near infrared light by 90 ° by the dichroic mirror 32 and shoots the image by the IR image sensor 33 in order to separate and shoot the near infrared light and the visible light collected by the lens 31. . In addition, the camera 3 passes visible light through the dichroic mirror 32 and takes an image with the visible imaging element 34.

Here, the surface structure of the IR imaging device 33 and the visible imaging element 34, for example, 640 pixels / line × 480 lines VGA (V ideo G raphics A rray ) is the size. The number of pixels and the number of lines affect the resolution and are not limited to such VGA sizes.

  Also, the number of frames taken is, for example, 30 frames / second. The number of shot frames can be determined according to the capability of the near-infrared image analysis / processing unit 5. For example, when thinning imaging is performed at 15 frames / second or 7.5 frames / second, the blood vessel detection accuracy is slightly reduced, but the operation is the same as that at 30 frames / second.

  The IR imaging device 33 selects near-infrared light in the same wavelength band as the near-infrared LED that is the first light source (for example, 820 nm to 880 nm when the emission wavelength of the near-infrared LED is 820 nm to 880 nm). It has spectral characteristics to transmit. As a result, the IR imaging device 33 can perform high-sensitivity blood vessel imaging with this spectral characteristic.

  And the schematic diagram which showed the near-infrared image data which the near-infrared image data generation part 4 produced | generated based on the signal which IR imaging element 33 image | photographed the surface of the biological body 2 in this way is FIG. ). The image data in FIG. 2A is composed of monochrome with different brightness of black and white. In addition, as shown in FIG. 2A, the blood vessels 21 and 22 in the contour of the photographed living body 2 have lower luminance than other parts, and are thus confirmed as black eye streaks.

  Then, as shown in FIG. 2B, when this image data is decomposed with pixels, in the whole living body 2, the parts other than the blood vessels 21 and 22 have a relatively high number of pixels. Further, the blood vessel 21 is decomposed into pixels shown in gray because it has a lower luminance than other parts, and the blood vessel 22 is decomposed into darker pixels because it has a lower luminance than the blood vessel 21.

  Next, an operation in which the blood vessel visualization device according to the first embodiment detects a blood vessel portion (a blood vessel portion obtained by combining the artery portion and the vein portion) from the near-infrared image data in FIG. 2 will be described. In the following, for the sake of specific explanation, a case where near-infrared imaging at 30 frames / second in the VGA size is considered.

  The near-infrared image analysis / processing unit 5 is generated by the near-infrared image data generation unit 4 in a period of one pulsation period (about 1 second) corresponding to 60 to 75 pulses / minute which is an average pulse rate of a general person. A luminance average value, a luminance maximum value, and a luminance minimum value are calculated for each pixel of the plurality of image data.

  That is, the near-infrared image analysis / processing unit 5 calculates a luminance average value, a luminance maximum value, and a luminance minimum value for pixels corresponding to 30 frames of image data in each pixel within 640 × 480 pixels. The near-infrared image analysis / processing unit 5 includes three sets of registers (luminance average value register, luminance maximum value register, and luminance minimum value register) for temporarily storing the luminance average value, luminance maximum value, and luminance minimum value. ) Is provided.

  The method for calculating the average brightness value, the maximum brightness value, and the minimum brightness value is as follows. First, as the luminance average value, the luminance average value generation unit 51 cyclically adds 30 frames of pixels for one second corresponding to one pulsation period, and finally divides by 30 (30 frames). Is stored in the luminance average value register. Thereby, the luminance average value generation unit 51 can detect and store the luminance average value in each pixel.

  Further, as the maximum luminance value, the maximum luminance value detection / storage unit 52 stores the initial pixel luminance in the maximum luminance value register at each pixel at the start of the first frame shooting, and during the shooting up to the 30th frame. If a luminance value higher than the stored value of the luminance maximum value register is input, the luminance value is replaced with a higher luminance value and stored. Thereby, the maximum brightness value detection / storage unit 52 can detect and store the maximum brightness value in each pixel.

  Further, as the lowest luminance value, the lowest luminance value detection / storage unit 53, like the highest luminance value detection / storage unit 52, receives a luminance value lower than the storage value of the lowest luminance value register in each pixel. Replace with a lower luminance value and save. Thereby, the lowest brightness value detection / storage unit 53 can detect and save the lowest brightness value in each pixel.

  Then, the luminance histogram generation / blood vessel discrimination threshold setting unit 54 obtains a frequency distribution of the luminance average value in each pixel of the VGA size generated by the luminance average value generation unit 51, and a histogram as shown in FIG. , The average brightness value, and the vertical axis indicates the frequency).

  As shown in FIG. 3, the histogram has peaks at three locations, and the peak with the highest luminance average value is the first peak P1 corresponding to a portion other than the blood vessels 21 and 22 in the whole living body 2 described above. (Bioluminance peak other than blood vessels), and the frequency is larger than other peaks.

  The peak with the second highest average brightness value is the second peak P2 (the brightness peak of the vein) corresponding to the blood vessel 21 described above, and the peak with the lowest average brightness value corresponds to the blood vessel 22 described above. This is the third peak P3 (the luminance peak at the artery). Furthermore, it can be confirmed that the luminance value of the first peak P1, which is a biological luminance peak other than the blood vessels, is separated from the luminance value of the second peak P2 due to the blood vessel portion.

  As a result, the luminance histogram generation / blood vessel discrimination threshold setting unit 54 sets a luminance value between the luminance value of the first peak P1 and the luminance value of the second peak P2 as the blood vessel discrimination threshold TH. Although FIG. 3 illustrates the case where the blood vessel determination threshold value TH is an intermediate luminance value between the luminance value of the first peak P1 and the luminance value of the second peak P2, it is not limited to this. That is, the blood vessel discrimination threshold TH may be a luminance value between the luminance value of the first peak P1 and the luminance value of the second peak P2.

  Then, the composite image data setting unit 55 sets pixels having luminance average values equal to or less than the blood vessel discrimination threshold TH set by the luminance histogram generation / blood vessel discrimination threshold setting unit 54 among the pixels stored in each of the three sets of registers. On the other hand, a blood vessel pixel (blood vessel pixel) is extracted by setting a blood vessel flag.

  Next, an operation for identifying veins and arteries performed after the composite image data setting unit 55 extracts blood vessel pixels will be described. The composite image data setting unit 55 according to the first embodiment determines whether or not the difference value between the highest luminance value and the lowest luminance value of each pixel among the extracted blood vessel pixels is less than a predetermined value defined in advance. Thus, it has the technical feature that it is possible to identify and visualize veins and arteries, as well as the blood flow state of the arteries.

  When the emission wavelength of the near-infrared LED as the first light source is 820 nm to 880 nm, the absorption intensity of near-infrared light having a wavelength of 820 nm to 880 nm is larger in oxyhemoglobin than deoxygenated hemoglobin. It is known that. Therefore, as shown in FIG. 3, it can be estimated that the second peak P2 on the left side of the first peak P1 is a vein, and the third peak P3 having a lower luminance is an artery.

  However, since the difference in the light absorption rate between the vein and the artery is smaller than the difference in the light absorption rate between these blood vessels and other living body parts, there is almost no difference in luminance. Therefore, in reality, the second peak P2 and the third peak P3 overlap without being separated, and thus it is difficult to accurately identify veins and arteries based on the average luminance value of each peak.

  Therefore, in the first embodiment, as a result of intensive studies, the flow of arterial blood moves in the blood vessel in the form of a wave called a pulse wave, while the flow of venous blood is flat. By paying attention, it was found that the veins and arteries can be identified and the blood flow state of the arteries can be visualized.

  That is, in the arterial portion, as the thickness of the arterial blood layer varies due to the pulse wave, the amount of oxyhemoglobin varies, so that the luminance value of each pixel for 30 frames per second corresponding to one pulsation cycle varies.

  On the other hand, since the venous blood flow is flat in the venous portion, the luminance value of each pixel for 30 frames per second corresponding to one pulsation cycle does not vary as compared with the arterial portion. Accordingly, it can be seen that the difference between the highest luminance value and the lowest luminance value is larger in the arterial portion because the variation in luminance value of each pixel for 30 frames per second is larger than in the vein portion.

  Therefore, the composite image data setting unit 55 calculates a difference value between the highest luminance value and the lowest luminance value for each pixel among the pixels for which the flag is set as the blood vessel pixel. Further, the composite image data setting unit 55 generates vein part image data that makes it possible to identify a pixel whose calculated difference value is less than a predetermined value defined in advance as a vein part. In addition, arterial part image data is generated that makes it possible to identify a pixel having a predetermined value or more as an arterial part.

  On the other hand, as described above, the visible image data generation unit 6 receives the signal of the visible imaging element 34 that captures the visible light that has passed through the dichroic mirror 32 and generates visible image data.

  Then, the image data composition processing unit 7 performs processing such as pixel position correction and composition ratio adjustment accompanying the optical axis shift between the IR image sensor 33 and the visible image sensor 34, thereby performing near-infrared image analysis / processing unit 5. Is combined with the visible image data generated by the visible image data generating unit 6 to generate combined image data.

  Further, the image data display unit 8 displays the image by processing the combined image data generated by the image data combining processing unit 7 into a signal format that can be displayed on a display device (for example, a liquid crystal monitor). This image display makes it possible to accurately identify and visualize veins and arteries. In addition, the blood vessel discrimination threshold is set by referring to the peak value of the luminance histogram, so that the blood vessel portion can be accurately identified even if the thickness of the living body part and near infrared irradiation intensity fluctuate. is there.

  In addition, if the hue processing is performed on the pixel identified by the composite image data setting unit 55 as the vein portion and the pixel identified as the artery portion, not only the vein and artery can be accurately identified but also the arterial blood flow state can be obtained. Can be visualized.

  That is, the composite image data setting unit 55 performs color-coding on each pixel that has a difference value less than a predetermined value and is identified as a vein using a first hue (for example, blue). Vein image data that can be visualized in blue is generated.

  On the other hand, the composite image data setting unit 55 has a second hue (for example, red) according to the magnitude of the difference value for each pixel that has a difference value that is equal to or greater than a predetermined value and is identified as an artery. ) Is used to distinguish colors according to light and shade contrast.

  That is, for a pixel identified as an arterial part, a pixel having a difference value substantially equal to a predetermined value divided from a vein part is, for example, a reddish color closest to the blue color of the vein part, and darker as the difference value increases. Arterial image data that can be visualized in red with increased brightness is generated.

  Similarly, the vein image data and the artery image data subjected to the hue processing are combined with the visible image data to generate composite image data, and the composite image data is displayed as an image.

  As a result, in the hue of the arterial portion, the portion where the difference value is small is the reddish color closest to the blue color of the vein portion, and the image data becomes darker as the difference value increases and can be visualized in red with increased brightness. Since it is set, the blood flow state of the artery can be accurately visualized based on the hue display.

  As described above, according to the first embodiment of the present invention, the blood vessel visualization device applies the appropriate threshold value calculated based on the luminance histogram to the near-infrared image data, so that the blood vessel portion (blood vessel) Pixel) can be extracted.

  Furthermore, the blood vessel visualization device compares the difference value between the highest luminance value and the lowest luminance value of each pixel in the period of one pulsation cycle among the blood vessel pixels extracted from the near-infrared image data, and a predetermined value defined in advance. Based on the above, it is possible to distinguish the pixel of the arterial part (arterial part image data) and the pixel of the venous part (venous part image data).

  As a result, not only blood vessels can be visualized, but also blood vessels that can be accurately identified and visualized with veins and arteries by displaying the combined image data that combines the arterial image data and the vein image data with the visible image data. A device can be obtained.

  Further, the blood vessel visualization device can generate arterial image data that has been subjected to hue processing according to the magnitude of the difference value for the arterial portion. As a result, since the conventional apparatus visualizes and displays the image data obtained by photographing the reflected light by performing only image processing such as edge processing and contrast enhancement, the blood flow state of the artery can be accurately visualized. A blood vessel visualization device can be obtained.

  In the first embodiment, the camera 3 has been described as receiving near infrared light reflected from the near-infrared LED array 1 on the living body 2. Even if the infrared LED array 1 receives transmitted light of near-infrared light irradiated on the living body 2 (light passing through the living body 2), the same effect can be obtained.

Embodiment 2. FIG.
<1. Function and operation of blood vessel visualization device with arterial occlusion monitoring function>
In the first embodiment, not only blood vessel visualization but also a blood vessel visualization device capable of accurately identifying and visualizing veins and arteries and accurately visualizing a blood flow state of an artery has been described. On the other hand, in the second embodiment of the present invention, a blood vessel visualization apparatus provided with an arterial occlusion monitoring function capable of managing changes in the blood flow state in the artery in time series will be described.

  FIG. 4 is a block diagram showing a functional configuration of a blood vessel visualization device having an arterial occlusion monitoring function according to Embodiment 2 of the present invention. The blood vessel visualization apparatus having the arterial occlusion monitoring function in FIG. 4 is further provided with an ID management / display control unit 9 and an arterial occlusion monitoring data generation unit in addition to the functional units constituting the blood vessel visualization apparatus in FIG. 10 is provided. Here, the ID management / display control unit 9 and the arterial occlusion monitoring data generation unit 10 correspond to an arterial occlusion monitoring control unit.

  The functional configuration shown in FIG. 4 is exactly the same as the functional configuration described in FIG. 1 in the first embodiment except for the ID management / display control unit 9 and the arterial occlusion monitoring data generation unit 10. Description is omitted.

  Here, the blood vessel visualization apparatus having the arterial occlusion monitoring function according to the second embodiment has a blockage confirmation value (blood flow index value) obtained by measuring the same part of the artery over time, or a blockage monitoring pixel. Has a technical feature of notifying the user of a part where the difference value is less than the lower limit difference value defined in advance.

  Next, regarding the series of operations of the blood vessel visualization apparatus having the arterial occlusion monitoring function according to the second embodiment, the functions and operations of the newly added ID management / display control unit 9 and arterial occlusion monitoring data generation unit 10 will be mainly described. Explained. FIG. 5 is an explanatory diagram regarding functions and operations of the blood vessel visualization device having an arterial occlusion monitoring function according to Embodiment 2 of the present invention.

  First, functions and operations of the ID management / display control unit 9 and the arterial occlusion monitoring data generation unit 10 will be described. The ID management / display control unit 9 includes a mouse and a key input device (not shown), and causes the image data display unit 8 to display the arterial occlusion monitoring screen shown in FIG.

  The arterial occlusion monitoring screen includes an operation button (“ID information input” button, “examination point setting” button, and “occlusion confirmation” button), a list table (arterial blood flow index list), and the previous implementation. In the first embodiment, the arterial part image data and the composite image data obtained by synthesizing the arterial part image data with the visible image data are displayed.

  The ID management / display control unit 9 has a function of setting an arterial occlusion monitoring marker 23 (a monitoring area where arterial occlusion monitoring should be performed) by operating a mouse on the arterial occlusion monitoring screen.

  The arterial occlusion monitoring data generation unit 10 compares the difference between each arterial pixel in a plurality of arterial pixels (arterial pixels) that fall within the monitoring area of the arterial occlusion monitoring marker 23 set by the setting function of the ID management / display control unit 9. A value (difference between the highest luminance value and the lowest luminance value) is calculated. Further, the arterial occlusion monitoring data generation unit 10 calculates the average value of the difference values by adding the respective difference values in the monitoring area and dividing by the number of arterial pixels.

  The range of the monitoring area of the arterial occlusion monitoring marker 23 can be set by an operation button in the arterial occlusion monitoring screen. The arterial occlusion monitoring data generation unit 10 has a function of saving the calculated average value as an occlusion confirmation value in the arterial occlusion monitoring register.

  Further, the ID management / display control unit 9 displays the screen of the living body 2 and the synthesized image data of the living body 2 in the previous embodiment 1 on the entire screen when the user performs a predetermined key operation with the key input device. The screen is switched alternately between the displayed screen and the arterial occlusion monitoring screen. Note that, for a predetermined key operation, for example, the screen may be switched alternately every time the F1 key is operated.

  Next, a series of operations of the blood vessel visualization device having the arterial occlusion monitoring function in the second embodiment will be described. When operating a blood vessel visualization apparatus having an arterial occlusion monitoring function, the ID management / display control unit 9 selects an ID information input screen (FIG. Open (not shown).

  By opening the ID information input screen, the user can input ID information such as personal information and examination site information for specifying a patient who uses the apparatus in advance using a mouse and a key input device.

  Next, when the user selects an “examination point setting” button with the mouse, the ID management / display control unit 9 displays an arterial occlusion monitoring marker 23 for monitoring the arterial occlusion on the screen on which the composite image data is displayed. Then, the user moves the arterial occlusion monitoring marker 23 to the position of the artery site to be examined using the mouse, and further clicks to set the arterial occlusion monitoring site.

  In this state, when the user selects an “occlusion confirmation” button with the mouse, the arterial occlusion monitoring data generation unit 10 averages the difference values of the arterial pixels that fall within the monitoring area of the arterial occlusion monitoring marker 23 as described above. Calculate the value (blocking confirmation value).

  Then, the arterial occlusion monitoring data generation unit 10 stores the occlusion confirmation value associated with the ID information set by the ID management / display control unit 9 and the position of the monitoring area of the arterial occlusion monitoring marker 23 in the arterial occlusion monitoring register. save. The arterial monitoring occlusion register stores an average value of occlusion confirmation values obtained by measuring for a predetermined time.

  Further, the ID management / display control unit 9 shows time-series data of a plurality of occlusion confirmation values obtained by measuring the same part of the artery where the monitoring area is set over time (periodically) as shown in FIG. As shown, the arterial blood flow index list is displayed. For example, the occlusion confirmation value measured every month is stored in association with the patient ID, thereby enabling diagnosis based on time-series display.

  As a method for displaying time-series data, for example, as shown in FIG. 5, the blockage confirmation value at the reference time is set as the blood flow index value 100, and the blockage check values at other times are relative to the reference. Display it. Thereby, it is possible to know how much the blood flow index value changes in time series, and it is possible to monitor the fluctuation of the blood flow state.

  Further, while FIG. 5 illustrates the case of displaying the time series data of the blockage confirmation value obtained when measuring every month, the present invention is not limited to this. In other words, the interval of the measurement period may be changed as necessary.

  Furthermore, the arterial occlusion monitoring control unit according to the second embodiment having the ID management / display control unit 9 and the arterial occlusion monitoring data generation unit 10 also has the following monitoring control function.

  Specifically, the arterial occlusion monitoring data generation unit 10 continues whether the difference value calculated by the near-infrared image analysis / processing unit 5 is less than a predetermined lower limit difference value for the pixel identified as the artery part. Monitor. Then, when the arterial occlusion monitoring data generation unit 10 detects a pixel whose difference value is less than the lower limit difference value, the arterial occlusion monitoring data generation unit 10 identifies the pixel as an occlusion monitoring pixel that is considered to have occluded.

  Further, the ID management / display control unit 9 can automatically display the vicinity area of the specified occlusion monitoring pixel as the arterial occlusion monitoring marker 24 as shown in FIG. Thereby, also about parts other than the arterial occlusion monitoring marker 23, based on the change in the difference value of the occlusion monitoring pixel, it is possible to know the arterial part where the occlusion is considered to occur, and to monitor the change in the blood flow state Can do.

  As described above, the arterial occlusion monitoring control unit according to the second embodiment performs the first arterial occlusion monitoring function for monitoring and controlling the site of the preset arterial occlusion monitoring marker 23, and monitoring control of the entire arterial part. It may be configured to include both of the second arterial occlusion monitoring function for detecting the site of the arterial occlusion monitoring marker 24 based on the above, or may be configured to include either one.

  As described above, according to the second embodiment of the present invention, the blood vessel visualization device provided with the arterial occlusion monitoring function calculates the occlusion confirmation value of the arterial portion in which the monitoring area is set, Time series data of a plurality of obstruction confirmation values (blood flow index values) can be obtained.

  In addition, if the difference value of the pixel identified as the arterial portion is continuously monitored to determine whether it is less than the lower limit difference value defined in advance and a pixel whose difference value is less than the lower limit difference value is detected, the pixel is blocked. It is specified as a blockage monitoring pixel that is considered to have occurred.

  Then, by displaying the time-series data of the occlusion confirmation value or the occlusion monitoring pixel on the screen, it is possible to monitor the change in the blood flow state in the same part of the artery. Furthermore, if there is an abnormality in the fluctuation of the blood flow state, it is possible to know the site where the abnormality is present, thereby preventing the onset of arterial occlusion.

  1 near-infrared LED array, 2 living body, 3 camera, 4 near-infrared image data generation unit, 5 near-infrared image analysis / processing unit, 6 visible image data generation unit, 7 image data composition processing unit, 8 image data display unit , 9 ID management / display control unit, 10 Arterial occlusion monitoring data generation unit, 21, 22 Blood vessel, 23, 24 Arterial occlusion monitoring marker, 31 Lens, 32 Dichroic mirror, 33 IR imaging device, 34 Visible imaging device, 51 Luminance average A value generation unit, 52 luminance maximum value detection / storage unit, 53 luminance minimum value detection / storage unit, 54 luminance histogram generation / blood vessel discrimination threshold setting unit, 55 synthetic image data setting unit.

Claims (7)

A first light source for irradiating a living body with near-infrared light;
The near infrared light reflected or transmitted from the living body by irradiating the living body with the near infrared light, and the visible light reflected or transmitted from the living body by irradiating the living body with visible light. A camera to image,
A near-infrared image data generation unit that generates near-infrared image data of the living body based on the near-infrared light captured by the camera;
A visible image data generating unit that generates visible image data of the living body based on the visible light captured by the camera;
A luminance average value, a luminance maximum value, and a luminance minimum value are calculated for each pixel constituting the plurality of near-infrared image data generated by the near-infrared image data generation unit during a pulsation period of a blood vessel. Based on the frequency distribution of the luminance average value calculated for each pixel, a threshold value for performing blood vessel discrimination is specified, pixels having the luminance average value equal to or less than the threshold value are extracted as blood vessel portions, A difference value between the highest luminance value and the lowest luminance value calculated in the period of the pulsation cycle is calculated for each pixel extracted as the blood vessel part, and the calculated difference value is compared with a predetermined value defined in advance. Based on this, the vein part image data that enables the pixel of the blood vessel part whose difference value is less than the predetermined value to be identified as a vein part is generated, and the pixel of the blood vessel part whose difference value is equal to or greater than the predetermined value A near-infrared image analysis and processing unit for generating an arterial part image data to be identified as the arterial section,
By synthesizing the vein image data and the artery image data generated by the near-infrared image analysis / processing unit and the visible image data generated by the visible image data generation unit, the living body, the vein And an image data composition processing unit for generating composite image data capable of identifying the arterial part,
A blood vessel visualization device comprising: an image data display unit that displays the composite image data generated by the image data synthesis processing unit. The blood vessel visualization device according to claim 1,
The near-infrared image analysis / processing unit color-codes pixels corresponding to the vein part using a first hue to generate the vein part image data, and sets pixels corresponding to the artery part to the difference value A blood vessel visualization device, wherein the arterial part image data is generated by color-coding according to light and shade contrast using a second hue according to the size. The blood vessel visualization device according to claim 1 or 2,
A function of setting a monitoring area to be monitored for arterial occlusion from the arterial part of the composite image data displayed on the image data display unit, and pulsation of the blood vessel for the arterial part in the set monitoring area First arterial occlusion monitoring having a function of calculating an average value of difference values of pixels calculated in a period of a cycle as an occlusion confirmation value and a function of displaying the calculated occlusion confirmation value on the image data display unit A blood vessel visualization device, further comprising a control unit. The blood vessel visualization device according to claim 3,
The first arterial occlusion monitoring control unit has a function of calculating the occlusion confirmation value in the monitoring area over time, and displaying time series data of the occlusion confirmation value calculated over time on the image data display unit. And a blood vessel visualization device. The blood vessel visualization device according to any one of claims 1 to 4,
Regarding the pixel identified as the arterial portion, a pixel whose difference value calculated by the near-infrared image analysis / processing unit is less than a predetermined lower-limit difference value is identified as a blockage monitoring pixel that is considered to have been blocked. And a second arterial occlusion monitoring control unit having a function of displaying the specified occlusion monitoring pixel on the image data display unit. The blood vessel visualization device according to any one of claims 1 to 5,
The range of the emission wavelength of the near infrared light that the first light source irradiates the living body is 820 nm to 880 nm. A blood vessel visualization method executed by a blood vessel visualization device to identify and display a vein part and an arterial part in a living body by processing an imaging signal from a camera,
The near-infrared light signal reflected or transmitted from the living body by being irradiated with near infrared light, and the visible light signal reflected or transmitted from the living body by being irradiated with visible light. An imaging step of imaging as the imaging signal by the camera;
A near-infrared image data generation step of generating near-infrared image data of the living body based on the near-infrared light signal imaged in the imaging step;
A visible image data generating step for generating visible image data of the living body based on the visible light signal imaged in the imaging step;
A luminance average value, a luminance maximum value, and a luminance minimum value are calculated for each pixel constituting the plurality of near infrared image data generated in the near infrared image data generation step in the period of the pulsation cycle of the blood vessel. A calculation step;
Based on the frequency distribution of the average brightness value calculated for each pixel in the calculation step, a threshold value for performing blood vessel identification is specified, and pixels having the average brightness value equal to or less than the threshold value are extracted as blood vessel portions. A blood vessel extraction step;
The difference value between the highest luminance value and the lowest luminance value calculated by the calculation step in the period of the pulsation cycle of the blood vessel is calculated for each pixel extracted as the blood vessel part, and the calculated difference value Based on a comparison with a predetermined value that is defined in advance, vein image data is generated that makes it possible to identify a pixel of the blood vessel that has a difference value less than the predetermined value as a vein portion, and the difference value is the predetermined value An arterial part / venous part identifying step for generating arterial part image data that makes it possible to identify a pixel of the blood vessel part that is greater than or equal to a value as an arterial part;
By combining the vein part image data and the arterial part image data generated in the arterial part / vein part identifying step and the visible image data generated in the visible image data generating step, the living body, An image data composition processing step for generating composite image data capable of identifying the vein part and the arterial part;
A blood vessel visualization method comprising: an image data display step for displaying the combined image data generated in the image data combining processing step.

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