Endoscope device and method for measuring hemoglobin concentration

Abstract

The invention provides a hemoglobin concentration measurement endoscope device and method, and relates to the technical field of endoscopes. A narrow-band light combination 1 and a narrow-band light combination 2 are utilized to alternately illuminate a target tissue to obtain a color image 1 and a color image 2, reflection information sensitive to shallow-layer, middle-layer and deep-layer hemoglobin is extracted from the color image 1 and the color image 2, and shallow-layer, middle-layer and deep-layer hemoglobin indexes are obtained through scattering correction and background light correction. Carrying out normalization correction on the hemoglobin index by utilizing the hemoglobin light absorption coefficient; and finally, calculating the hemoglobin concentration based on the corrected hemoglobin index and outputting a concentration distribution diagram. According to the method, the comprehensive distribution of blood vessels in superficial, middle and deep tissues can be reflected more accurately, the hemoglobin concentration of the tissues can be measured more accurately, and meanwhile, the requirement of real-time image observation of an endoscope is met.

Description

Technical Field

[0001] The present invention relates to an endoscope device, and in particular to an endoscope device and method for measuring hemoglobin concentration, which obtains hemoglobin concentration information in biological tissue based on taking narrow-band multispectral images of biological tissue. Background Art

[0002] With the advancement of medical technology, the function of endoscopes is no longer limited to simple image observation, but has gradually shifted to quantitative analysis of biological tissue components. Among them, hemoglobin, as a key oxygen transport substance in the blood, has attracted particular attention in terms of its concentration measurement.

[0003] In the measurement of hemoglobin concentration, images are usually obtained by using illumination light around 500-600nm, and then the index representing the total hemoglobin concentration is calculated, and finally the distribution of the total hemoglobin concentration of biological tissues is given. This is because the absorption band of hemoglobin around 500-600nm has a relatively large absorption coefficient and can relatively sensitively reflect the changes in tissue hemoglobin concentration.

[0004] However, the penetration depth of 500-600nm light in biological tissues is basically the same, and cannot more accurately reflect the comprehensive distribution of hemoglobin concentrations in shallow, middle, and deep blood vessels.

[0005] Therefore, an endoscopic device for measuring hemoglobin concentration is proposed to more accurately measure the hemoglobin concentration of tissues while ensuring that the endoscope can meet the needs of real-time image observation. Summary of the invention

[0006] The present specification provides an endoscopic device and method for measuring hemoglobin concentration, which utilizes the absorption characteristics of hemoglobin of light of different wavelengths and their different penetration depths in biological tissues to obtain hemoglobin concentration information in the shallow, middle and deep layers of biological tissues, thereby more accurately giving the distribution of hemoglobin concentration. At the same time, it utilizes narrow-band light combination illumination and synchronous acquisition of color images to ensure real-time observation of endoscopic images.

[0007] This specification provides an endoscopic device for measuring hemoglobin concentration, which comprises:

[0008] A light source unit that generates at least a narrow-band light combination 1 and a narrow-band light combination 2 as illumination light;

[0009] A photographing unit, which outputs a color image 1 and a color image 2 by photographing the reflected light of the biological tissue illuminated by the narrow-band light combination 1 and the narrow-band light combination 2 respectively;

[0010] A processing unit calculates and corrects the hemoglobin index pixel by pixel based on the color image 1 and the color image 2, thereby obtaining the hemoglobin concentration value in the biological tissue, specifically,

[0011] The processing unit calculates hemoglobin indexes IHb1, IHb2, and IHb3 that are correlated with the hemoglobin content in the superficial layer, middle layer, and deep layer of the tissue according to the color image 1 and the color image 2.

[0012] The processing unit performs normalization correction on the hemoglobin index according to the hemoglobin absorption coefficient at the corresponding wavelength to obtain IHb1', IHb2', and IHb3'.

[0013] The processing unit obtains the hemoglobin concentration value of the tissue based on the relationship between the corrected hemoglobin indices IHb1', IHb2', and IHb3' and the hemoglobin concentration.

[0014] Optionally, the narrow-band light combination 1 includes narrow-band light near the 415nm absorption peak of hemoglobin, narrow-band light near the 540nm absorption peak of hemoglobin, and narrow-band light near 650nm for background correction.

[0015] The central wavelength deviation of the narrow-band light is ±10 nm.

[0016] Optionally, the narrow-band light combination 2 includes narrow-band light near 450nm for scattering correction and narrow-band light near the 590nm absorption peak of hemoglobin,

[0017] The central wavelength deviation of the narrow-band light is ±10 nm.

[0018] Optionally, the light source unit at least includes the narrow-band light sources in the narrow-band light combination 1 and the narrow-band light combination 2.

[0019] Each light source in the light source unit has a full width at half maximum of ≤40nm, and the brightness of the light source can be adjusted.

[0020] The light source unit switches between emitting narrow-band light combination 1 and narrow-band light combination 2 to illuminate biological tissue.

[0021] Optionally, the photographing unit has a pixel array that is sensitive to the illumination light of the light source unit.

[0022] The imaging unit is provided with red, green, and blue color filters, and can capture the biological tissue illuminated by the light from the light source unit to generate a color image.

[0023] The imaging unit includes a synchronization controller, and synchronously records the corresponding color image 1 and color image 2 when the narrow-band light combination 1 and the narrow-band light combination 2 are illuminated.

[0024] Optionally, the processing unit obtains the red, green and blue components of corresponding pixels in color image 1 and color image 2, and calculates the hemoglobin index of the shallow, middle and deep layers of the tissue pixel by pixel, specifically as follows:

[0025]

[0026]

[0027]

[0028] Wherein, Ib1 is the pixel blue component of the color image 1 obtained by photographing under the illumination of the narrow-band light combination 1,

[0029] Ig1 is the pixel green component of color image 1 captured under the illumination of narrow-band light combination 1,

[0030] Ir1 is the pixel red component of color image 1 captured under the illumination of narrow-band light combination 1,

[0031] Ib2 is the pixel blue component of color image 2 captured under the illumination of narrow-band light combination 2,

[0032] Irg2 is the sum of the green component and the red component of the pixel of the color image 2 captured under the illumination of the narrow-band light combination 2.

[0033] Optionally, the processing unit, based on IHb3, performs normalization correction on the hemoglobin index as follows:

[0034]

[0035] IHb3'=IHb3

[0036] Among them, ε1 is the integral value of the hemoglobin absorption coefficient of narrow-band light near 415nm,

[0037] ε2 is the integral value of the hemoglobin absorption coefficient of narrow-band light near 540nm,

[0038] ε3 is the integrated value of the hemoglobin absorption coefficient of narrow-band light around 590 nm.

[0039] Optionally, the processing unit comprises a processor and a memory for storing an executable program and a data table, and when the executable program is executed, the processor executes the processing method in any one of the above-mentioned devices.

[0040] Furthermore, the relationship between the corrected hemoglobin indices IHb1', IHb2', IHb3' and the hemoglobin concentration in the present invention can be obtained by the following method: using standard tissue samples that can simulate shallow, middle and deep blood vessels, obtaining color image 1 and color image 2 based on the shooting unit under different known hemoglobin concentrations, and using the processing unit to calculate the corrected hemoglobin indices IHb1', IHb2', IHb3' of the standard tissue samples based on the color images 1 and the color images 2, thereby obtaining a numerical table or function of the relationship between the corrected hemoglobin indices and the hemoglobin concentration.

[0041] Furthermore, the standard tissue sample uses polymethyl methacrylate (PMMA) as a substrate, a cavity made of polydimethylsiloxane (PDMS) material is embedded in the substrate to simulate a blood vessel, and a film made of PDMS material doped with titanium dioxide is covered on the substrate, and the film has three different thicknesses, and the films of different thicknesses are combined with the simulated blood vessels to respectively simulate deep, middle and superficial blood vessels;

[0042] Plastic pipes are used to connect simulated blood vessels, peristaltic pumps and washing bottles to form a circulation system. The peristaltic pump is used to provide power for blood circulation and control the blood flow rate. Pure blood and pure water in different proportions are added to the washing bottle, and after being evenly mixed through the circulation system, blood with different hemoglobin concentrations is formed. In addition, oxygen or nitrogen can be introduced into the gas inlet of the washing bottle to change the blood oxygen saturation.

[0043] A method for measuring hemoglobin concentration based on an endoscopic device is implemented using the device as described in any of the above items.

[0044] In the present invention, the absorption characteristics and penetration depths of light of different wavelengths are comprehensively considered to obtain hemoglobin concentration information at different depths. In particular, for more accurate measurement, narrowband wavebands of 650nm and 450nm are introduced to reduce the interference of tissue background reflection and scattering. Narrowband wavebands of 415nm, 540nm and 590nm are used in combination to more comprehensively calculate the hemoglobin in shallow, medium and deep blood vessels. Meanwhile, a matching processing flow and standard tissue samples for simulating blood vessels are designed to accurately realize hemoglobin concentration measurement while greatly reducing the experimental difficulty. The scheme of the present invention solves the problem of inaccurate hemoglobin concentration estimation in existing methods, while ensuring real-time display of endoscopic images. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings used in the description of the embodiments. The drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 It is the absorption spectrum of hemoglobin and the penetration depth curve of light of different wavelengths.

[0047] Figure 2 Schematic diagram of the penetration depth of light of different wavelengths in biological tissues with layered structures.

[0048] Figure 3 It is a schematic diagram of the relative wavelength positions of the light source spectra of narrow-band light combination 1 and narrow-band light combination 2 and the hemoglobin absorption spectrum and penetration depth curve.

[0049] Figure 4A It is a schematic diagram showing the relative wavelength positions of the light source spectrum of the narrow-band light combination 1 and the transmission spectrum of the filter of the image sensor of the imaging unit.

[0050] Figure 4B It is a schematic diagram showing the relative wavelength positions of the light source spectrum of the narrow-band light combination 2 and the transmission spectrum of the filter of the image sensor of the imaging unit.

[0051] Figure 5 This is a structural diagram of the light source unit.

[0052] Figure 6 This is a structural diagram of the camera unit.

[0053] Figure 7 A schematic diagram showing synchronous control of a light source unit, an imaging unit, and a processing unit.

[0054] Figure 8 A sequence diagram showing the lighting of a narrow-band light combination and synchronous acquisition of a color image.

[0055] Fig. 9 It is a flow chart of the hemoglobin concentration calculation of the present invention.

[0056] Fig.10 It is a schematic diagram of the structure of a standard tissue sample of hemoglobin.

[0057] Fig.11A This is a schematic diagram of the hemoglobin concentration distribution measured under violet light illumination.

[0058] Fig. 11B This is a schematic diagram of the hemoglobin concentration distribution measured under green light illumination.

[0059] Fig. 11C This is a schematic diagram of the hemoglobin concentration distribution measured under orange light illumination.

[0060] Fig.11D It is a schematic diagram of the hemoglobin concentration distribution measured under the present invention. DETAILED DESCRIPTION

[0061] Hereinafter, a mode for carrying out the present invention will be described with reference to the drawings.

[0062] The endoscope apparatus according to the embodiment of the present invention described below is an apparatus that quantitatively calculates the hemoglobin concentration of the photographed biological tissue based on two color images obtained by illumination with the narrow-band light combination 1 and the narrow-band light combination 2, and displays the concentration distribution result in an image. In the quantitative analysis of the hemoglobin concentration using this apparatus, the property that the absorption characteristics of hemoglobin by light having different penetration depths in biological tissues correspond to changes in the hemoglobin concentration is utilized.

[0063] Before describing the endoscope apparatus according to the embodiment of the present invention, the spectral characteristics of hemoglobin and the penetration depths of light of different wavelengths will be described.

[0064] Figure 1 The absorption spectrum of hemoglobin and the penetration depth curves of light of different wavelengths are shown. In addition, Figure 2 The penetration depth of light of different wavelengths in biological tissue with stacked structures is shown. Figure 1 The solid line in the middle is the absorption spectrum of hemoglobin in the range of 400-700 nm11. Figure 1The middle dotted line is the penetration depth of light in the range of 400-700nm in biological tissues 12. The absorption spectrum 11 shows that hemoglobin has absorption peaks near 415nm 13, near 540nm 14, and near 580nm 15, respectively, which can relatively sensitively reflect changes in hemoglobin concentration. The penetration depth of light near 415nm 13 is comparable to that of light in the range of 400-440nm 16P, which is relatively shallow and can only detect blood vessels 22s in the surface 21s; the penetration depth of light near 540nm 14 is comparable to that of light in the range of 470-580nm 16G, which is moderate and can detect blood vessels 22s in the surface 21s and blood vessels 22m in the middle 21m, but when the blood vessels overlap in the vertical direction, the information of the two will interfere with each other; the penetration depth of light near 580nm 15 and hemoglobin The absorption coefficient is equivalent to the light around 540nm 14, and it does not provide more information; although the light in the 480-610nm range 16O deviates from the absorption peak around 580nm 15, the corresponding hemoglobin absorption coefficient can still reflect the change of hemoglobin concentration, and its penetration depth is significantly increased, which can detect the blood vessels 22m in the middle layer 21m and the blood vessels 22d in the deep layer 21d. Since the hemoglobin absorption coefficient is relatively small and the surface blood vessels are thin, it cannot well reflect the blood vessels 22s in the surface layer 21s. In addition, the scattering effect is obvious in biological tissues, and the light in the 440-470nm range 16B is sensitive to scattering, and it is used to perform normalization correction for tissue scattering. In addition, the light in the 610-700nm range 16R has weak absorption of hemoglobin and a deeper penetration depth, and is less affected by tissue and blood vessel absorption, so it is used to perform normalization correction for illumination background light.

[0065] According to the above analysis, the embodiment of the present invention selects five narrow-band lights for illumination, and combines a color image sensor with a color filter, and adopts a combined illumination form to achieve the purpose of real-time measurement of hemoglobin concentration.

[0066] Figure 3 The relative wavelength positions of the light source spectra of narrow-band light combination 1 and narrow-band light combination 2 and the hemoglobin absorption spectrum and penetration depth curve are shown. In addition, Figure 4A and Figure 4B The relative wavelength positions of the light source spectra of narrow-band light combination 1 and narrow-band light combination 2 and the transmission spectrum of the filter of the image sensor of the imaging unit are shown respectively.

[0067] As an example of the present invention, narrowband light combination 1 is composed of narrowband light 31, narrowband light 32 and narrowband light 33, narrowband light combination 2 is composed of narrowband light 34 and narrowband light 35, and the half-height full width of the narrowband light is ≤40nm. The image sensor of the camera unit includes a blue filter 41, a green filter 42 and a red filter 43, and the wavelength region with a transmittance of more than 10% in each color filter is defined as each color region. That is, Figure 4AOr as shown in 4B, the blue region is 400-525nm, the green region is 470-610nm, and the red region is 590-700nm.

[0068] The central wavelength of narrowband light 31 is 415nm, which is sensitive to the change of surface hemoglobin concentration; the central wavelength of narrowband light 32 is 540nm, which is sensitive to the change of middle hemoglobin concentration; the central wavelength of narrowband light 33 is 650nm, and its hemoglobin absorption coefficient is low, and it is used for background light correction. Narrowband light 31, narrowband light 32 and narrowband light 33 are located in the blue area, green area and red area respectively, and color image 1 is obtained under the illumination of narrowband light combination 1, and the reflection signals of narrowband light 31, narrowband light 32 and narrowband light 33 after passing through the tissue are obtained from the blue, green and red channel values ​​of color image 1.

[0069] The central wavelength of narrowband light 34 is 450nm, which is sensitive to tissue scattering and is used for tissue scattering correction; the central wavelength of narrowband light 35 is 590nm, which is sensitive to changes in deep hemoglobin concentration. Narrowband light 34 is located in the blue area, and narrowband light 35 is located at the junction of the green area and the red area. Color image 2 is obtained under the illumination of narrowband light combination 2. The reflection signal of narrowband light 34 after passing through the tissue is obtained from the blue channel value of color image 2, and the reflection signal of narrowband light 35 after passing through the tissue is obtained from the sum of the values ​​of the green channel and the red channel of color image 2.

[0070] The narrowband light is generated by the light source. Figure 5 The light source unit is composed of a light source box 51 and a light source control unit 52.

[0071] The light source box at least includes the five narrow-band light sources of the narrow-band light combination 1 and the narrow-band light combination 2, and the narrow-band light source can be a laser or an LED. Figure 5 The structure shown is arranged such that the light is combined by the beam combiner 516, collimated by the collimator 517, and finally emitted from a unified outlet for illumination, so that multiple narrow-band light sources can be lit at the same time to illuminate in a narrow-band light combination manner. The above light source box structure is only an example, and more light source box structures can be used to meet the needs according to professional knowledge.

[0072] The light source control unit 52 is connected to the narrow-band light sources 511, 512, 513, 514, and 515, and changes the brightness of the narrow-band light source, or the on and off of the light source, by changing the driving current or voltage. The light source control unit 52 can control the light source box to illuminate with narrow-band light combination 1 or narrow-band light combination 2.

[0073] Under the illumination of narrow-band light combination, the camera unit is used to obtain color images. Figure 6 The imaging unit is composed of an image sensor 61 and an image control unit 62.

[0074] The image sensor 61 is a color image sensor, which separates the three wavelength regions of the blue region, the green region and the red region, and independently generates a blue channel value, a green channel value and a red channel value. The image sensor 61 can be a CMOS or CCD image sensor covered with a Bayer array filter, and the Bayer array filter includes a blue filter 41, a green filter 42 and a red filter 43.

[0075] The image control unit 62 is used to adjust the exposure time, gain and other parameters of the image sensor, control image acquisition, and output color image data.

[0076] The light source control unit 52 and the image control unit 62 must work in synchronization. Figure 7 The synchronous controller 71 controls the light source control unit 52 to illuminate with narrowband light combination 1 or narrowband light combination 2, and synchronously controls the image control unit 62 to collect color image 1 or color image 2. The color image collected under synchronous control is input to the processing unit 72 to calculate the hemoglobin concentration.

[0077] Figure 8 It is a sequence diagram of the narrow-band light combination lighting and synchronously collecting color images. Image acquisition is divided into odd frames and even frames. In odd frames, narrow-band light combination 1 is used for illumination, that is, 415nm narrow-band light 31, 540nm narrow-band light 32 and 650nm narrow-band light 33 are lit at the same time to obtain color image 1. In even frames, narrow-band light combination 2 is used for illumination, that is, 450nm narrow-band light 34 and 590nm narrow-band light 35 are lit at the same time to obtain color image 2. The processing unit processes the obtained color image 1 and color image 2 of two adjacent frames and gives the hemoglobin concentration result in real time.

[0078] The odd-numbered frames and the even-numbered frames can also be illuminated by the narrow-band light combination 2 and the narrow-band light combination 1 respectively, and the principle is the same.

[0079] The processing unit calculates the hemoglobin concentration based on the obtained color image, Fig. 9 It is a flow chart of hemoglobin concentration calculation, which includes 5 processing steps.

[0080] Image acquisition 91 acquires color image 1 and color image 2 of two adjacent frames.

[0081] Information extraction 92, extracting the reflection signal of the narrow-band light after passing through the tissue from the color image. Specifically, the reflection signal Ib1 of 415nm light, the reflection signal Ig1 of 540nm light and the reflection signal Ir1 of 650nm light are extracted from the blue, green and red channels of color image 1 respectively, the reflection signal Ib2 of 450nm light is extracted from the blue channel of color image 2, and the reflection signal Irg2 of 590nm light is obtained by summing the green and red channel values ​​of color image 2.

[0082] The hemoglobin index calculation 93 calculates the superficial hemoglobin index IHb1, the middle hemoglobin index IHb2 and the deep hemoglobin index IHb3 according to the following formula.

[0083]

[0084]

[0085]

[0086] Hemoglobin index correction 94, according to the absorption coefficient integral value ε1 of hemoglobin near 415nm narrow-band light, the absorption coefficient integral value ε2 of hemoglobin near 540nm narrow-band light, and the absorption coefficient integral value ε3 of hemoglobin near 590nm narrow-band light, the hemoglobin index is normalized and corrected, and the deep hemoglobin index is kept unchanged. IHb1', IHb2', and IHb3' are the corrected shallow, middle, and deep hemoglobin indices, respectively.

[0087]

[0088]

[0089] IHb3'=IHb3

[0090] Hemoglobin concentration calculation 95, the hemoglobin concentration value of the tissue is obtained according to the numerical table or function of the relationship between the corrected hemoglobin index IHb1', IHb2', IHb3' and the hemoglobin concentration. The numerical table or function used is previously calibrated based on the endoscope device and the standard tissue sample. The function can be in the form of an n-order polynomial about IHb1', IHb2', IHb3', but it is recommended that n does not exceed 3.

[0091] Fig.10 1 is a schematic diagram of the structure of a standard tissue sample. Polymethyl methacrylate (PMMA) is used as the substrate 101. A cavity made of polydimethylsiloxane (PDMS) is embedded in the substrate 101 to simulate a blood vessel 102, and the diameter of the blood vessel 102 is different. In order to simulate tissue scattering, the substrate 101 is covered with doped titanium dioxide (TiO 2 ) of PDMS material, the thickness of the films 103a, 103b and 103c are different, and they are combined with the blood vessel 102 to simulate deep, middle and superficial blood vessels respectively.

[0092] The blood vessel 102, the peristaltic pump 105 and the washing bottle 106 are connected by a plastic pipe 104 to form a circulation system. The peristaltic pump 105 provides power for blood circulation and controls the blood flow rate. Pure blood and pure water in different proportions are added to the washing bottle 106, and after being evenly mixed by the circulation system, blood with different hemoglobin concentrations is formed; and oxygen or nitrogen is introduced through the gas inlet 106a of the washing bottle 106 to change the blood oxygen saturation of the blood. In this phantom structure, since PMMA and PDMS are both highly light-transmitting materials, the influence of their thickness can be ignored. The PDMS film doped with titanium dioxide has a scattering effect and is used to simulate the mucosal tissue covering the blood vessel. Its different thickness means that the depth of the blood vessel in the tissue is different. In actual production, the amount of titanium dioxide added in PDMS can be controlled to control the normalized scattering coefficient of the obtained film to make it close to the tissue to be simulated. By controlling the thickness of the covering film to be close to the depth of the blood vessel in the tissue to be simulated, deep, middle and shallow blood vessels can be simulated; for example, endoscopes are often used in digestive organs. In the method, when making a standard tissue sample simulating a digestive organ, a film with a mass ratio of titanium dioxide to PDMS of 0.8%-1.0% can be used, and its normalized scattering coefficient is close to that of gastric mucosal tissue. When the substrate is covered with the film with a thickness of 50-200 μm, the PDMS simulated blood vessels below can simulate the superficial blood vessels. When the substrate is covered with the film with a thickness of 200-500 μm, the PDMS simulated blood vessels below can simulate the middle blood vessels. When the substrate is covered with the film with a thickness of 500 μm-1 mm, the PDMS simulated blood vessels below can simulate the deep blood vessels. In actual tissues, the shallower the blood vessels are, the thinner they are. However, the thickness of the blood vessels does not need to be considered in the simulation, because the calculated hemoglobin index will offset the influence of the different optical paths caused by the different thickness of the blood vessels. For ease of production, the diameter of the superficial blood vessels can be made into 100-300 μm, the diameter of the middle blood vessels can be made into 300 μm-1 mm, and the diameter of the deep blood vessels can be made into 1-3 mm.

[0093] By using the above standard tissue samples, the same method of the present invention can be used to perform experiments under different known hemoglobin concentrations to determine the corrected hemoglobin index corresponding to the simulated superficial, middle and deep blood vessels, thereby obtaining a numerical table or function of the relationship between the corrected hemoglobin index and the hemoglobin concentration. The phantom structure of the present invention greatly reduces the difficulty of the experiment required to obtain the numerical table or function of the relationship.

[0094] Fig.11A , Fig. 11B , Fig. 11C Schematic diagrams of the hemoglobin concentration distribution of the measured tissues under illumination of 415nm narrow-band light 31, 540nm narrow-band light 32, and 590nm narrow-band light 35 respectively. Fig.11DSchematic diagram of the hemoglobin concentration distribution obtained under the present invention. They are all grayscale images, in which the grayscale value corresponds to the hemoglobin concentration. In some embodiments of the present invention, the grayscale image can also be a pseudo-color image, and different colors correspond to different hemoglobin concentrations. FIG. 11A to FIG. 11D By comparison, we can see that:

[0095] If the hemoglobin concentration is measured using only the 415 nm narrow-band light 31, only the hemoglobin information of the superficial capillaries 22s can be extracted.

[0096] Measuring the hemoglobin concentration using only the 540 nm narrow-band light 32 can extract the hemoglobin information of the superficial capillaries 22s and the middle-layer blood vessels 22m, but in the case of overlapping blood vessels, the information of the two will interfere with each other.

[0097] By measuring the hemoglobin concentration using only the 590nm narrow-band light 35, the hemoglobin information of the middle-layer blood vessels 22m and the deep-layer thick blood vessels 22d can be extracted. Since the superficial blood vessels 22s are thinner and the hemoglobin absorption coefficient to the 590nm narrow-band light 35 is smaller, it is difficult to extract the superficial blood vessel information. In addition, in the case of overlapping blood vessels, the middle-layer and deep-layer information will also interfere with each other.

[0098] The method of the present invention can more accurately obtain the hemoglobin concentration of biological tissues.

[0099] The hemoglobin information of the superficial thin blood vessels 22s is directly obtained from the 415nm narrow-band light 31 signal; the hemoglobin information of the middle blood vessels 22m is obtained by deducting the signal contribution of the superficial thin blood vessels 22s from the 540nm narrow-band light 32 signal; the hemoglobin information of the deep thick blood vessels 22d is obtained by deducting the signal contribution of the superficial thin blood vessels 22s and the middle blood vessels 22m from the 590nm narrow-band light 35 signal. Therefore, when the tissue reflection signals of the 415nm narrow-band light 31, the 540nm narrow-band light 32 and the 590nm narrow-band light 35 are used at the same time, the embodiment of the present invention can independently extract the hemoglobin information of the superficial thin blood vessels 22s, the middle blood vessels 22m and the deep thick blood vessels 22d, and thus can more accurately express the hemoglobin concentration of the tissue. The above-mentioned effect also makes the numerical table or function of the relationship between the corrected hemoglobin index IHb1', IHb2', IHb3' and the hemoglobin concentration obtained by calibration of the standard tissue sample more accurately reflect the real situation.

[0100] In addition, the signals of 630nm narrow-band light 33 and 450nm narrow-band light 34 are used to normalize the tissue background reflection and tissue scattering, respectively, thereby reducing the deviation of the hemoglobin concentration calculation result caused by tissue differences. At the same time, the narrow-band light combination 1 and the narrow-band light combination 2 are used in an alternating illumination manner to realize the rapid calculation and real-time display of the hemoglobin concentration distribution diagram.

Claims

1. An endoscopic device for measuring hemoglobin concentration, characterized in that: have: A light source unit that generates at least a narrow-band light combination 1 and a narrow-band light combination 2 as illumination light; A photographing unit, which outputs a color image 1 and a color image 2 by photographing the reflected light of the biological tissue illuminated by the narrow-band light combination 1 and the narrow-band light combination 2 respectively; A processing unit, which calculates and corrects the hemoglobin index pixel by pixel based on the color image 1 and the color image 2, and then obtains the hemoglobin concentration value in the biological tissue; The processing unit calculates the hemoglobin indexes IHb1, IHb2, and IHb3 that are correlated with the hemoglobin content in the superficial, middle, and deep layers of the tissue according to the color image 1 and the color image 2. The processing unit performs normalization correction on the hemoglobin index according to the hemoglobin absorption coefficient at the corresponding wavelength to obtain IHb1', IHb2', and IHb3'. The processing unit obtains the hemoglobin concentration value of the tissue based on the relationship between the corrected hemoglobin indices IHb1', IHb2', and IHb3' and the hemoglobin concentration.

2. The endoscopic device for measuring hemoglobin concentration according to claim 1, characterized in that: The narrowband light combination 1 includes narrowband light near a peak wavelength of 415 nm, narrowband light near a peak wavelength of 540 nm, and narrowband light near a peak wavelength of 650 nm. The central wavelength deviation of the narrow-band light is ±10 nm.

3. The endoscopic device for measuring hemoglobin concentration according to claim 1, characterized in that: The narrowband light combination 2 includes narrowband light with a peak wavelength of about 450 nm and narrowband light with a peak wavelength of about 590 nm. The central wavelength deviation of the narrow-band light is ±10 nm.

4. The endoscopic device for measuring hemoglobin concentration according to claim 1, characterized in that: The light source unit at least comprises the narrow-band light combination 1 in the device of claim 2 and the narrow-band light combination 2 in the device of claim 3. Each light source in the light source unit has a full width at half maximum of ≤40nm, and the brightness of the light source can be adjusted. The light source unit switches between emitting narrow-band light combination 1 and narrow-band light combination 2 to illuminate biological tissue.

5. The endoscopic device for measuring hemoglobin concentration according to claim 1, characterized in that: The imaging unit includes a pixel array having sensitivity to the illumination light of the light source unit. The imaging unit is provided with red, green, and blue color filters, and can capture the biological tissue illuminated by the light from the light source unit to generate a color image. The imaging unit includes a synchronization controller, and synchronously records the corresponding color image 1 and color image 2 when the narrow-band light combination 1 and the narrow-band light combination 2 are illuminated.

6. The endoscopic device for measuring hemoglobin concentration according to claim 1, characterized in that: The processing unit obtains the red, green and blue components of the corresponding pixels in the color image 1 and the color image 2, and calculates the hemoglobin indexes IHb1, IHb2 and IHb3 of the shallow, middle and deep layers of the tissue pixel by pixel, as follows: Wherein, Ib1 is the pixel blue component of the color image 1 obtained by photographing under the illumination of the narrow-band light combination 1, Ig1 is the pixel green component of color image 1 captured under the illumination of narrow-band light combination 1, Ir1 is the pixel red component of color image 1 captured under the illumination of narrow-band light combination 1, Ib2 is the pixel blue component of color image 2 captured under the illumination of narrow-band light combination 2, Irg2 is the sum of the green component and the red component of the pixel of the color image 2 captured under the illumination of the narrow-band light combination 2.

7. The endoscopic device for measuring hemoglobin concentration according to claim 1, characterized in that: The processing unit, based on IHb3, normalizes and corrects the hemoglobin index as follows: IHb3'=IHb3 Among them, ε1 is the integral value of the hemoglobin absorption coefficient of narrow-band light near the peak wavelength of 415nm, ε2 is the integral value of the hemoglobin absorption coefficient of narrow-band light near the peak wavelength of 540nm, ε3 is the integrated value of the hemoglobin absorption coefficient of narrow-band light near the peak wavelength of 590 nm.

8. The endoscope device for measuring hemoglobin concentration according to claim 1, characterized in that: The relationship between the corrected hemoglobin indices IHb1', IHb2', IHb3' and the hemoglobin concentration is obtained by the following method: using standard tissue samples that can simulate shallow, middle and deep blood vessels, obtaining color images 1 and color images 2 based on the shooting unit under different known hemoglobin concentrations, and using the processing unit to calculate the corrected hemoglobin indices IHb1', IHb2', IHb3' of the standard tissue samples based on the color images 1 and the color images 2, thereby obtaining a numerical table or function of the relationship between the corrected hemoglobin indices and the hemoglobin concentration.

9. The endoscopic device for measuring hemoglobin concentration according to claim 8, characterized in that: The standard tissue sample uses polymethyl methacrylate (PMMA) as a substrate, a cavity made of polydimethylsiloxane (PDMS) material is embedded in the substrate to simulate a blood vessel, and a film made of PDMS material doped with titanium dioxide is covered on the substrate, the film has three different thicknesses, and the films of different thicknesses are combined with the simulated blood vessels to simulate deep, middle and superficial blood vessels respectively; Plastic pipes are used to connect simulated blood vessels, peristaltic pumps and washing bottles to form a circulation system. The peristaltic pump is used to provide power for blood circulation and control the blood flow rate. Pure blood and pure water in different proportions are added to the washing bottle, and after being evenly mixed through the circulation system, blood with different hemoglobin concentrations is formed. In addition, oxygen or nitrogen can be introduced into the gas inlet of the washing bottle to change the blood oxygen saturation.

10. A method for measuring hemoglobin concentration based on an endoscopic device, characterized in that: The method is implemented by any one of claims 1 to 9.

Images