An endoscopic device and method for measuring hemoglobin concentration

Abstract

The application provides a hemoglobin concentration measuring endoscope device and method, and relates to the technical field of endoscopes. The target tissue is alternately illuminated by narrow-band light combination 1 and narrow-band light combination 2, color image 1 and color image 2 are obtained, reflection information sensitive to shallow, middle and deep hemoglobin is extracted therefrom, shallow, middle and deep hemoglobin indexes are obtained by using scattering correction and background light correction, the hemoglobin indexes are normalized and corrected by using a hemoglobin absorption coefficient, and finally, the hemoglobin concentration is calculated based on the corrected hemoglobin indexes and a concentration distribution map is output. The application can more accurately reflect the comprehensive distribution of blood vessels in the shallow, middle and deep tissues, and further more accurately measure the hemoglobin concentration of the tissues, while ensuring the need for real-time image observation of the endoscope.

Description

Technical Field

[0001] This invention relates to an endoscopic device, and more particularly to an endoscopic device and method for measuring hemoglobin concentration, which obtains hemoglobin concentration information in biological tissues by capturing narrow-band multispectral images of biological tissues. Background Technology

[0002] With the advancement of medical technology, the function of endoscopy is no longer limited to simple image observation, but is gradually shifting towards quantitative analysis of biological tissue components. Among them, the concentration measurement of hemoglobin, as a key oxygen transport substance in blood, is of particular interest.

[0003] In hemoglobin concentration measurements, images are typically captured using illumination around 500-600 nm, and then an index representing total hemoglobin concentration is calculated to ultimately determine the distribution of total hemoglobin concentration in biological tissues. This is because the absorption band of hemoglobin around 500-600 nm has a relatively large absorption coefficient, allowing it to relatively sensitively reflect changes in tissue hemoglobin concentration.

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

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

[0006] This specification provides an endoscopic device and method for measuring hemoglobin concentration. It utilizes the absorption characteristics of hemoglobin by different wavelengths of light and their different penetration depths in biological tissues to obtain hemoglobin concentration information in the superficial, middle, and deep layers of biological tissues, thereby providing a more accurate distribution of hemoglobin concentration. At the same time, it uses narrowband light combined 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 includes:

[0008] The light source unit generates at least narrowband light combination 1 and narrowband light combination 2 as illumination light;

[0009] The imaging unit captures the light reflected from biological tissue under illumination by narrowband light combination 1 and narrowband light combination 2 respectively, and outputs color image 1 and color image 2.

[0010] The processing unit, based on the color images 1 and 2, calculates and corrects the hemoglobin index pixel by pixel to obtain the hemoglobin concentration value in the biological tissue. Specifically,

[0011] The processing unit calculates hemoglobin indices IHb1, IHb2, and IHb3, which are correlated with the hemoglobin content in the superficial, middle, and deep layers of tissue, based on color image 1 and color image 2.

[0012] The processing unit normalizes and corrects the hemoglobin index based on the hemoglobin absorbance coefficient at the corresponding wavelength to obtain IHb1', IHb2', and IHb3'.

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

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

[0015] The center wavelength deviation of the narrowband light is ±10nm.

[0016] Optionally, the narrowband light combination 2 includes narrowband light near 450 nm for scattering correction and narrowband light near the absorption peak of hemoglobin at 590 nm.

[0017] The center wavelength deviation of the narrowband light is ±10nm.

[0018] Optionally, the light source unit includes at least the narrowband light source found in narrowband light combination 1 and narrowband light combination 2.

[0019] Each light source in the light source section has a full width at half maximum (FWHM) of ≤40nm, and the brightness of the light source is adjustable.

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

[0021] Optionally, the imaging unit includes a pixel array that is sensitive to the illumination light from the light source.

[0022] The imaging unit is equipped with red, green, and blue color filters, and can capture images of biological tissue illuminated by the light source to generate color images.

[0023] The imaging unit is equipped with a synchronization controller, which synchronously records the corresponding color image 1 and color image 2 when the narrowband light combination 1 and narrowband light combination 2 are used for illumination.

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

[0025]

[0026]

[0027]

[0028] Wherein, Ib1 is the blue component of the pixel in the color image 1 obtained under the illumination of narrowband light combination 1.

[0029] Ig1 is the green component of a pixel in a color image 1 captured under narrowband light combination 1 illumination.

[0030] Ir1 is the red component of a pixel in a color image 1 captured under narrowband light combination 1 illumination.

[0031] Ib2 is the blue component of the pixel in the color image 2 obtained under narrowband light combination 2 illumination.

[0032] Irg2 is the sum of the green and red components of the pixels in the color image 2 obtained under the illumination of the narrowband light combination 2.

[0033] Optionally, the processing unit, using IHb3 as a reference, normalizes and corrects the hemoglobin index as follows:

[0034]

[0035] IHb3'=IHb3

[0036] Where ε1 is the integral value of the hemoglobin absorptivity in the narrow band light around 415nm.

[0037] ε2 is the integral value of the hemoglobin absorptivity in the narrow band light around 540 nm.

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

[0039] Optionally, the processing unit includes a processor and a memory storing an executable program and a data table, wherein when the executable program is executed, it causes the processor to perform the processing method in any of the above-described devices.

[0040] Furthermore, the relationship between the corrected hemoglobin indices IHb1', IHb2', IHb3' and hemoglobin concentration described in this invention can be obtained by the following method: using standard tissue samples capable of simulating superficial, intermediate, and deep blood vessels, color images 1 and 2 are obtained based on the imaging unit under different known hemoglobin concentrations, and the processing unit calculates the corrected hemoglobin indices IHb1', IHb2', and IHb3' of the standard tissue samples based on color images 1 and 2, thereby obtaining a numerical table or function showing the relationship between the corrected hemoglobin indices and hemoglobin concentration.

[0041] Furthermore, the standard tissue sample uses polymethyl methacrylate (PMMA) as a substrate, embedding cavities made of polydimethylsiloxane (PDMS) material in the substrate to simulate blood vessels, and covering the substrate with a thin film made of PDMS material doped with titanium dioxide. The thin film has three different thicknesses, and the different thicknesses of the thin film combined with the simulated blood vessels respectively simulate deep, middle and superficial blood vessels.

[0042] A circulatory system is formed by connecting simulated blood vessels, a peristaltic pump, and a gas washing bottle through plastic tubing. The peristaltic pump provides power for blood circulation and controls the blood flow rate. Different proportions of pure blood and pure water are added to the gas washing bottle and mixed evenly through the circulatory system to form blood with different hemoglobin concentrations. In addition, oxygen or nitrogen can be introduced into the gas inlet of the gas washing bottle to change the blood oxygen saturation.

[0043] A method for measuring hemoglobin concentration using an endoscopic device, implemented using the device described in any of the preceding claims.

[0044] In this invention, the absorption characteristics and penetration depth of light of different wavelengths are comprehensively considered to obtain hemoglobin concentration information at different depths. In particular, for more accurate measurement, 650nm and 450nm narrowband bands are introduced to reduce interference from tissue background reflection and scattering. The 415nm, 540nm and 590nm narrowband bands are used in combination to more comprehensively calculate hemoglobin in superficial, intermediate and deep blood vessels. At the same time, a matching processing flow and standard tissue samples for simulating blood vessels are designed to accurately measure hemoglobin concentration while greatly reducing the experimental difficulty. The solution of this invention solves the problem of inaccurate hemoglobin concentration estimation in existing methods, while ensuring real-time display of endoscopic images. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments are briefly introduced below. The accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 It shows the absorption spectrum of hemoglobin and the penetration depth curves of light at different wavelengths.

[0047] Figure 2 This is a schematic diagram showing the penetration depth of light of different wavelengths in layered biological tissues.

[0048] Figure 3 This is a schematic diagram showing the relative wavelength positions of the light source spectra of narrowband light combination 1 and narrowband light combination 2 with the hemoglobin absorption spectrum and penetration depth curve.

[0049] Figure 4A This is a schematic diagram showing the relative wavelength positions of the light source spectrum of the narrowband light combination 1 and the transmission spectrum of the filter of the image sensor in the camera section.

[0050] Figure 4B This is a schematic diagram showing the relative wavelength positions of the light source spectrum of the narrowband light combination 2 and the transmission spectrum of the filter of the image sensor in the camera section.

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

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

[0053] Figure 7 A schematic diagram showing the synchronous control of the light source, camera, and processing units is provided.

[0054] Figure 8 This diagram shows a sequence of narrowband light combinations illuminating and simultaneously acquiring color images.

[0055] Figure 9 This is a flowchart of the hemoglobin concentration calculation method of the present invention.

[0056] Figure 10 This is a schematic diagram of the structure of a standard tissue sample containing hemoglobin.

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

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

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

[0060] Figure 11D This is a schematic diagram of the hemoglobin concentration distribution measured under the present invention. Detailed Implementation

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

[0062] The endoscopic device described below, according to embodiments of the present invention, is a device that quantitatively calculates the hemoglobin concentration of a biological tissue based on two color images captured under illumination by narrowband light combination 1 and narrowband light combination 2, and displays the concentration distribution results in an image format. In the quantitative analysis of hemoglobin concentration using this device, the property that the absorption characteristics of light with different penetration depths in biological tissue correspond to changes in hemoglobin concentration is utilized.

[0063] Before describing the endoscopic device according to the embodiments of the present invention, the spectral characteristics of hemoglobin and the penetration depth of light of different wavelengths will be explained.

[0064] Figure 1 The absorption spectrum of hemoglobin and the penetration depth curves of light at different wavelengths are shown. Additionally, Figure 2 This demonstrates the penetration depth of light at different wavelengths in layered biological tissues. Figure 1 The solid line represents the absorption spectrum of hemoglobin in the 400-700 nm range. Figure 1The dashed line represents the penetration depth of light in biological tissues in the 400-700 nm range. Absorption spectra show that hemoglobin has absorption peaks near 415 nm, 540 nm, and 580 nm, which can relatively sensitively reflect changes in hemoglobin concentration. The penetration depth of light near 415 nm (13) is comparable to that of light in the 400-440 nm range (16P), but relatively shallow, only able to detect superficial vessels (21s) and intermediate vessels (22s). The penetration depth of light near 540 nm (14) is comparable to that of light in the 470-580 nm range (16G), moderate, able to detect superficial vessels (21s) and intermediate vessels (21m), but when vessels overlap vertically, the information from both types of light interferes. The penetration depth of light near 580 nm (15) is similar to that of hemoglobin. The absorption coefficient of light in the 480-610nm range (16O) is comparable to that of light near 540nm (14), and it does not provide much information. Although light in the 480-610nm range (16O) deviates from the absorption peak near 580nm (15), the corresponding hemoglobin absorption coefficient can still reflect changes in hemoglobin concentration, and its penetration depth is significantly increased, enabling the detection of vessels in the middle layer (21m) and the deep layer (21d). However, due to the relatively small absorption coefficient of hemoglobin and the finer surface vessels, it cannot effectively reflect the surface layer (21s) vessels (22s). Furthermore, scattering effects are significant in biological tissues; light in the 440-470nm range (16B) is sensitive to scattering and can be used for normalization correction of tissue scattering. Additionally, light in the 610-700nm range (16R) has weak absorption by hemoglobin and a deeper penetration depth, and is less affected by tissue and vascular absorption; it can be used for normalization correction of the background illumination.

[0065] Based on the above analysis, the embodiments of the present invention select five narrowband lights for illumination and combine them with a color image sensor with color filters to achieve the purpose of real-time measurement of hemoglobin concentration.

[0066] Figure 3 The relative wavelength positions of the light source spectra of narrowband light combination 1 and narrowband light combination 2 with the hemoglobin absorption spectrum and penetration depth curves are shown. Additionally, Figure 4A and Figure 4B The relative wavelength positions of the light source spectra of narrowband light combination 1 and narrowband light combination 2 with the transmission spectrum of the filter of the image sensor of the camera unit are shown respectively.

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

[0068] Narrowband light 31 has a center wavelength of 415 nm and is sensitive to changes in surface hemoglobin concentration; narrowband light 32 has a center wavelength of 540 nm and is sensitive to changes in mesohemoglobin concentration; narrowband light 33 has a center wavelength of 650 nm and has a low hemoglobin absorption coefficient, and is used for background light correction. Narrowband lights 31, 32, and 33 are located in the blue, green, and red regions, respectively. A color image 1 is obtained under the illumination of narrowband light combination 1. The reflection signals of narrowband lights 31, 32, and 33 after passing through the tissue are obtained from the blue, green, and red channel values ​​of color image 1, respectively.

[0069] Narrowband light 34 has a center wavelength of 450 nm and is sensitive to tissue scattering, used for tissue scattering correction. Narrowband light 35 has a center wavelength of 590 nm and is sensitive to changes in deep hemoglobin concentration. Narrowband light 34 is located in the blue region, and narrowband light 35 is located at the boundary between the green and red regions. 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 and red channels of color image 2.

[0070] Narrowband light is generated by the light source unit. Figure 5 This is an example of the structure of the light source section. The light source section consists of a light source box 51 and a light source control section 52.

[0071] The light source box contains at least five narrowband light sources, namely narrowband light combination 1 and narrowband light combination 2, as described above. These narrowband light sources can be lasers or LEDs. Narrowband light sources 511, 512, 513, 514, and 515 are arranged according to... Figure 5 The structure shown uses a beam combiner (516) to combine the light beams, collimating them with a collimator (517), and finally outputting the light from a unified exit for illumination. Therefore, multiple narrowband light sources can be simultaneously illuminated using a narrowband light combination method. The above light source box structure is just one example; based on professional knowledge, many more light source box structures can be designed to meet various needs.

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

[0073] Under narrowband combined illumination, a camera unit is used to acquire color images. Figure 6 This is an example of a camera unit structure. The camera unit consists of an image sensor 61 and an image control unit 62.

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

[0075] The image control unit 62 is used to adjust parameters such as exposure time and gain 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 operate under synchronized conditions. Figure 7 This is a schematic diagram of synchronous control. The synchronous controller 71 controls the light source control unit 52 to provide illumination using narrowband light combination 1 or narrowband light combination 2, and synchronously controls the image control unit 62 to acquire color image 1 or color image 2. The color image acquired under synchronous control is input into the processing unit 72 to calculate the hemoglobin concentration.

[0077] Figure 8 This is a sequence of images where narrowband light combinations are used to illuminate and simultaneously acquire color images. Image acquisition is divided into odd-numbered frames and even-numbered frames. In odd-numbered frames, narrowband light combination 1 is used for illumination, i.e., 415nm narrowband light 31, 540nm narrowband light 32, and 650nm narrowband light 33 are illuminated simultaneously to obtain color image 1. In even-numbered frames, narrowband light combination 2 is used for illumination, i.e., 450nm narrowband light 34 and 590nm narrowband light 35 are illuminated simultaneously to obtain color image 2. The processing unit processes the acquired color images 1 and 2 from the two adjacent frames and provides the hemoglobin concentration result in real time.

[0078] Odd-numbered frames and even-numbered frames can also be illuminated using narrowband light combination 2 and narrowband light combination 1 respectively, based on the same principle.

[0079] The processing unit calculates hemoglobin concentration based on the acquired color image. Figure 9 This is a flowchart for calculating hemoglobin concentration, which includes 5 processing steps.

[0080] Image acquisition 91: Acquire color image 1 and color image 2 from two adjacent frames.

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

[0082] Hemoglobin index calculation 93, the superficial hemoglobin index IHb1, the intermediate hemoglobin index IHb2 and the deep hemoglobin index IHb3 are calculated according to the following formula.

[0083]

[0084]

[0085]

[0086] The hemoglobin index was corrected to 94 by normalizing the hemoglobin index based on the integral values ​​ε1, ε2, and ε3 of the absorption coefficients of hemoglobin in the narrow band light around 415 nm and around 540 nm, respectively, while keeping the deep hemoglobin index unchanged. IHb1', IHb2', and IHb3' represent the corrected superficial, intermediate, and deep hemoglobin indices, respectively.

[0087]

[0088]

[0089] IHb3'=IHb3

[0090] Hemoglobin concentration is calculated using a numerical table or function relating the corrected hemoglobin indices IHb1', IHb2', and IHb3' to hemoglobin concentration. The numerical table or function used is pre-calibrated based on the endoscopic apparatus and standard tissue samples. The function can be an nth-degree polynomial in relation to IHb1', IHb2', and IHb3', but n is recommended not to exceed 3.

[0091] Figure 10 This is a schematic diagram of a standard tissue sample. Polymethyl methacrylate (PMMA) is used as the substrate 101. Valves made of polydimethylsiloxane (PDMS) are embedded in the substrate 101 to simulate blood vessels 102, with varying diameters. To simulate tissue scattering, thin films 103a, 103b, and 103c made of titanium dioxide (TiO2)-doped PDMS are coated onto the substrate 101. The films 103a, 103b, and 103c have different thicknesses and, combined with the blood vessels 102, respectively simulate deep, middle, and superficial blood vessels.

[0092] A circulatory system is formed by connecting a blood vessel 102, a peristaltic pump 105, and a gas washing bottle 106 via a plastic pipe 104. The peristaltic pump 105 provides power for blood circulation and controls the blood flow rate. Different proportions of pure blood and pure water are added to the gas washing bottle 106, and after being mixed evenly by the circulatory system, blood with varying hemoglobin concentrations is formed. Oxygen or nitrogen is introduced through the gas inlet 106a of the gas washing bottle 106 to alter the blood's oxygen saturation. In this phantom structure, since both PMMA and PDMS are highly transparent materials, their thickness effect can be ignored. The titanium dioxide-doped PDMS film has a scattering effect, used to simulate the mucosal tissue covering blood vessels. Different thicknesses indicate different depths of blood vessels within the tissue. In actual fabrication, the amount of titanium dioxide in the PDMS can be controlled to adjust the normalized scattering coefficient of the resulting film, making it close to the tissue to be imitated. By controlling the thickness of the covering film to be similar to the depth of blood vessels in the tissue to be imitated, deep, middle, and superficial blood vessels can be simulated. For example, endoscopes are commonly used in digestive organs. In fabricating standard tissue samples mimicking digestive organs, a thin film with a titanium dioxide to PDMS mass ratio of 0.8%-1.0% can be used. Its normalized scattering coefficient is close to that of gastric mucosa tissue. Covering the substrate with this film with a thickness of 50-200 μm allows the PDMS-simulated blood vessels to simulate superficial vessels. Covering the substrate with a film with a thickness of 200-500 μm allows for the simulation of intermediate vessels, and covering the substrate with a film with a thickness of 500 μm-1 mm allows for the simulation of deep vessels. In actual tissue, shallower vessels tend to be thinner, but in the simulation, vessel diameter does not need to be considered because the calculated hemoglobin index will offset the effect of varying optical path lengths caused by different vessel diameters. For ease of fabrication, the diameter of superficial vessels can be fabricated to be 100-300 μm, intermediate vessels to 300 μm-1 mm, and deep vessels to 1-3 mm.

[0093] Using the aforementioned standard tissue samples, experiments conducted using the same method as described in this invention under different known hemoglobin concentrations can determine the corrected hemoglobin index corresponding to the simulated superficial, intermediate, and deep blood vessels. This allows for the generation of a numerical table or function relating the corrected hemoglobin index to hemoglobin concentration. The use of the phantom structure of this invention significantly reduces the experimental difficulty required to obtain this numerical table or function.

[0094] Figure 11A , Figure 11B , Figure 11C These are schematic diagrams showing the measured hemoglobin concentration distribution in tissues under illumination of 415nm narrowband light 31, 540nm narrowband light 32, and 590nm narrowband light 35, respectively. Figure 11DThese are schematic diagrams illustrating the hemoglobin concentration distribution obtained under this invention. All are grayscale images, where the grayscale values ​​correspond to the hemoglobin concentration. In some embodiments of this invention, the grayscale images may also be pseudo-color images, with different colors corresponding to different hemoglobin concentrations. Figures 11A to 11D The comparison shows that:

[0095] If only 415nm narrowband light is used to measure hemoglobin concentration, only hemoglobin information of superficial capillaries can be extracted for 22 seconds.

[0096] Using only 540nm narrowband light to measure hemoglobin concentration, hemoglobin information from superficial capillaries (22s) and mid-layer vessels (22m) can be extracted. However, in cases of overlapping vessels, the two types of information can interfere with each other.

[0097] Using only 590nm narrowband light 35 to measure hemoglobin concentration, it is possible to extract hemoglobin information from the middle layer vessels 22m and the deep coarse vessels 22d. However, due to the thinner size of the superficial vessels 22s and the smaller absorption coefficient of hemoglobin to 590nm narrowband light 35, it is difficult to extract information from the superficial vessels. Furthermore, in the case of overlapping vessels, the information from the middle and deep layers will also interfere with each other.

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

[0099] Hemoglobin information from superficial capillaries 22s is obtained directly from the 415nm narrowband light 31 signal; hemoglobin information from intermediate vessels 22m is obtained by subtracting the signal contribution from superficial capillaries 22s from the 540nm narrowband light 32 signal; and hemoglobin information from deep coarse vessels 22d is obtained by subtracting the signal contributions from superficial capillaries 22s and intermediate vessels 22m from the 590nm narrowband light 35 signal. Therefore, by simultaneously utilizing the tissue reflection signals from 415nm narrowband light 31, 540nm narrowband light 32, and 590nm narrowband light 35, the embodiments of the present invention can independently extract hemoglobin information from superficial capillaries 22s, intermediate vessels 22m, and deep coarse vessels 22d, thereby more accurately expressing the tissue hemoglobin concentration. The above-mentioned effect also makes the numerical table or function relating the corrected hemoglobin indices IHb1', IHb2', IHb3' and hemoglobin concentration, obtained from standard tissue samples, more accurately reflect the actual situation.

[0100] Furthermore, the signals from 630nm narrowband light 33 and 450nm narrowband light 34 are used to normalize the tissue background reflection and tissue scattering, respectively, reducing the deviation in hemoglobin concentration calculation results caused by tissue differences. Simultaneously, by employing alternating illumination with narrowband light combination 1 and narrowband light combination 2, rapid calculation and real-time display of the hemoglobin concentration distribution map can be achieved.

Claims

1. An endoscopic device for measuring hemoglobin concentration, characterized in that, have: The light source unit generates at least narrowband light combination 1 and narrowband light combination 2 as illumination light; the narrowband light combination 1 includes narrowband light with a peak wavelength of around 415 nm, narrowband light with a peak wavelength of around 540 nm, and narrowband light with a peak wavelength of around 650 nm; the narrowband light combination 2 includes narrowband light with a peak wavelength of around 450 nm and narrowband light with a peak wavelength of around 590 nm; the light source unit switches between emitting narrowband light combination 1 and narrowband light combination 2 to illuminate biological tissue; The imaging unit captures the light reflected from biological tissue under illumination by narrowband light combination 1 and narrowband light combination 2 respectively, and outputs color image 1 and color image 2. The processing unit calculates and corrects the hemoglobin index pixel by pixel based on the color image 1 and color image 2, thereby obtaining the hemoglobin concentration value in biological tissue. The processing unit calculates hemoglobin indices IHb1, IHb2, and IHb3, which are correlated with the hemoglobin content in the superficial, middle, and deep layers of tissue, based on color image 1 and color image 2. The processing unit acquires the red, green, and blue components of corresponding pixels in color images 1 and 2, and calculates the hemoglobin indices IHb1, IHb2, and IHb3 pixel-by-pixel, as follows: ， ， ， Wherein, Ib1 is the blue component of the pixel in the color image 1 obtained under the illumination of narrowband light combination 1. Ig1 is the green component of a pixel in a color image 1 captured under narrowband light combination 1 illumination. Ir1 is the red component of a pixel in a color image 1 captured under narrowband light combination 1 illumination. Ib2 is the blue component of the pixel in the color image 2 obtained under narrowband light combination 2 illumination. Irg2 is the sum of the green and red components of the pixels in the color image 2 obtained under the illumination of the narrowband light combination 2; The processing unit normalizes and corrects the hemoglobin index according to the hemoglobin absorbance coefficient at the corresponding wavelength to obtain IHb1', IHb2', and IHb3': ， ， ， in, This is the integral value of the hemoglobin absorbance coefficient for narrowband light near the peak wavelength of 415nm. This is the integral value of the hemoglobin absorbance coefficient for narrowband light near the peak wavelength of 540nm. This is the integral value of the hemoglobin absorption coefficient for narrowband light near the peak wavelength of 590nm; The processing unit obtains the tissue's hemoglobin concentration value based on the relationship between the corrected hemoglobin indices IHb1', IHb2', IHb3' and hemoglobin concentration.

2. The endoscopic device for measuring hemoglobin concentration as described in claim 1, characterized in that, The center wavelength deviation of the narrowband light is ±10nm.

3. The endoscopic device for measuring hemoglobin concentration as described in claim 1, characterized in that, Each light source in the light source section has a full width at half maximum (FWHM) of ≤40nm, and the brightness of the light source is adjustable.

4. The endoscopic device for measuring hemoglobin concentration as described in claim 1, characterized in that, The imaging unit includes a pixel array that is sensitive to the illumination light from the light source unit. The imaging unit is equipped with red, green, and blue color filters, and can capture images of biological tissue illuminated by the light source to generate color images. The imaging unit is equipped with a synchronization controller, which synchronously records the corresponding color image 1 and color image 2 when the narrowband light combination 1 and narrowband light combination 2 are used for illumination.

5. The endoscopic device for measuring hemoglobin concentration as described in claim 1, characterized in that, The relationship between the corrected hemoglobin indices IHb1', IHb2', IHb3' and hemoglobin concentration is obtained by the following method: using standard tissue samples that can simulate superficial, intermediate, and deep blood vessels, color images 1 and 2 are obtained based on the imaging unit under different known hemoglobin concentrations, and the processing unit calculates the corrected hemoglobin indices IHb1', IHb2', and IHb3' of the standard tissue samples based on color images 1 and 2, thereby obtaining a numerical table or function showing the relationship between the corrected hemoglobin indices and hemoglobin concentration.

6. The endoscopic device for measuring hemoglobin concentration as described in claim 5, characterized in that, The standard tissue sample uses polymethyl methacrylate (PMMA) as a substrate, with cavities made of polydimethylsiloxane (PDMS) material embedded in the substrate to simulate blood vessels, and a thin film made of PDMS material doped with titanium dioxide is covered on the substrate. The thin film has three different thicknesses, and the different thicknesses of the thin film combined with the simulated blood vessels respectively simulate deep, middle and superficial blood vessels. A circulatory system is formed by connecting simulated blood vessels, a peristaltic pump, and a gas washing bottle through plastic tubing. The peristaltic pump provides power for blood circulation and controls the blood flow rate. Different proportions of pure blood and pure water are added to the gas washing bottle and mixed evenly through the circulatory system to form blood with different hemoglobin concentrations. In addition, oxygen or nitrogen can be introduced into the gas inlet of the gas washing bottle to change the blood oxygen saturation.

7. A method for measuring hemoglobin concentration based on an endoscopic device, characterized in that, This is achieved using the endoscope device as described in any one of claims 1-6.

Images