Blood vessel imaging method and system based on near-infrared light
By using a combination of 770nm+850nm+900nm light sources and image processing technology, the imaging quality problem of vascular imaging devices in specific populations was solved, and high-quality vascular imaging was achieved.
Patent Information
- Application Number
- CN202311702091.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-12
- Publication Date
- 2026-02-13
AI Technical Summary
Existing vascular imaging devices have limited applicability and low image quality, especially in people with thicker fat deposits or darker skin.
Uniform illumination is achieved using a combination of 770nm+850nm+900nm light sources. Combined with an image processing module, denoising, anti-flickering, image enhancement, and deep learning segmentation are performed to obtain high-quality vascular images.
It improves the imaging quality of vascular imaging devices, expands their applicability, and can clearly display veins and arteries in people with thicker fat and darker skin.
Smart Images
Figure CN121512467A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of medical image processing technology, and in particular to a method and system for vascular imaging based on near-infrared light. Background Technology
[0002] The vein imaging system is designed based on the near-infrared characteristics of veins, and the theoretical basis for this is the Lambert-Beer law, which describes the relationship between the light absorption intensity of a substance at a specific wavelength and the concentration of the light-absorbing substance and the transmission distance.
[0003] I(l)=I0e -α1 =I0e -kCl (1)
[0004] As shown in formula (1), I0 represents the intensity of the incident light, α represents the absorption coefficient of the medium, l is the transmission distance of the incident light, I(l) is the light intensity after the light has traveled a certain distance, C represents the concentration of the absorbing medium, and k is the molar absorptivity, which is related to the wavelength of the incident light and the properties of the absorbing material itself, and is generally set as a constant. The tissues surrounding the vein reflect most of the near-infrared light of this wavelength. Conversely, deoxyhemoglobin in venous blood (or oxyhemoglobin in arterial blood) absorbs most of the near-infrared light in this band. Therefore, in images captured by cameras sensitive to short-wave near-infrared light, the vein is darker than the surrounding tissue, thus highlighting the vein's trajectory.
[0005] Near-infrared (NIR) light is essentially an electromagnetic wave, with a wavelength range between 780 nm and 3000 nm. Figure 1 As shown, near-infrared (NIR) light has a warming effect. Under the influence of NIR light, body temperature rises, blood flow accelerates, blood vessels dilate, circulation and metabolism are enhanced, and cell vitality and tissue regeneration are increased. Furthermore, NIR light also reduces the excitability of the nervous system, relieves muscle spasms, alleviates pain, and promotes nerve function. In conclusion, NIR light does not cause any harm to the human body in clinical treatment and is reliable and safe.
[0006] The theoretical model of the vein imaging system is as follows:
[0007]
[0008] In formula (2), A is absorbance and T is transmittance, which is the ratio between the intensity of the emitted light I(l) and the intensity of the incident light I0. The physical meaning of this model is that when a uniform, non-scattering light-absorbing material is perpendicularly irradiated by a light beam of a specific wavelength, its absorbance A and transmittance T are negatively correlated, while they are positively correlated with the concentration C of the light-absorbing material and its transmission distance l.
[0009] Then, near-infrared light is emitted at a suitable distance from the acquisition point. The data reflected back from the acquisition point enters the image processing motherboard or directly into the computer for image processing. Finally, the processed data is projected through a projector. Figure 2 As shown.
[0010] Existing vein imaging systems use a single near-infrared light wavelength range of approximately 700nm to 1100nm. Because different wavelengths have varying penetration capabilities into the skin, specifically... Figure 3 As shown, if a shorter wavelength, such as 760nm, is selected, although the absorption coefficient for venous and arterial blood is high, this range of short-wave near-infrared light is very susceptible to interference from visible light, and its penetration is also poor, resulting in poor imaging effects in individuals with thicker fat layers and darker skin. Conversely, if a longer wavelength, such as 960nm, is selected, although this range of short-wave near-infrared light has strong skin penetration, its absorption coefficient for venous blood is low, making it unsuitable for single-use imaging. In conclusion, existing vascular imaging devices have incomplete applicability and relatively low image quality. Summary of the Invention
[0011] To overcome the shortcomings of existing vascular imaging devices, such as limited applicability and low imaging quality, this invention proposes a vascular imaging method and system based on near-infrared light, the detailed technical solution of which is as follows:
[0012] A near-infrared light-based vascular imaging method, characterized by comprising the following steps: uniformly illuminating the test area using a combination of 770nm+850nm+900nm light sources, then acquiring an image of the near-infrared light reflected from the test area and preprocessing it to obtain an initial image; enhancing the initial image to obtain an enhanced image; segmenting the enhanced image to obtain a vascular image for projection; and projecting the vascular image onto the corresponding position of the test area.
[0013] Furthermore, the preprocessing step involves denoising and removing uniform flicker from the image to obtain an initial black and white image.
[0014] Furthermore, in image enhancement, an image contrast enhancement algorithm is used for image enhancement.
[0015] Furthermore, in image segmentation, a deep learning training model is used for image segmentation.
[0016] Furthermore, the combined light source includes a ring-shaped optical diffuser plate and a plurality of infrared light-emitting diodes disposed on the optical diffuser plate.
[0017] A near-infrared light-based vascular imaging system, used in the aforementioned near-infrared light-based vascular imaging method, includes a light source control module, a combined light source, an image processing module, an optomechanical module, a projector, a camera, a filter, and a housing. The light source control module controls the combined light source to emit near-infrared light of 770nm+850nm+900nm and illuminate the area to be measured. The camera acquires an image of the near-infrared light reflected from the area to be measured and performs preprocessing to obtain an initial image. The image processing module enhances the initial image to obtain an enhanced image. Then, the enhanced image is segmented to obtain a vascular image for projection. The optomechanical module controls the projection module to project the vascular image onto the corresponding position of the area to be measured.
[0018] Furthermore, the projection light path of the projector is perpendicular to the shooting light path of the camera; the bottom of the camera is provided with a housing with a right-angled trapezoidal cross-section; the bottom of the housing is provided with a plane mirror-type filter at a 45-degree angle; the projection light path of the projector coincides with the shooting light path of the camera after being reflected by the filter.
[0019] The beneficial effects of this invention are: In the case of a single near-infrared light source and multiple combined light sources, this invention selected 770nm+850nm+900nm near-infrared light as a combined light source through experimental methods, which improved the imaging quality of the vascular imaging instrument and made it suitable for people with thicker fat and darker skin, thus expanding the applicability of the vascular imaging instrument. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the wavelength range of near-infrared light.
[0021] Figure 2 This is a flowchart of the workflow of a blood vessel imaging system.
[0022] Figure 3 This is a graph showing the relationship between near-infrared light wavelength and penetration depth.
[0023] Figure 4 This is a graph showing the relationship between near-infrared light wavelength and absorption coefficient.
[0024] Figure 5 This is a comparison chart of the imaging effects of different light sources.
[0025] Figure 6 This is an initial schematic diagram of the present invention.
[0026] Figure 7 This is an enhanced image schematic diagram of the present invention.
[0027] Figure 8 This is a schematic diagram of blood vessel images according to the present invention.
[0028] Figure 9This is a schematic diagram of the imaging effect of the present invention.
[0029] Figure 10 This is a schematic diagram of the system of the present invention.
[0030] Wherein: 100—projector; 200—camera; 300—filter; 500—combined light source; 600—housing. Detailed Implementation
[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0032] To improve the imaging quality and applicability of existing vascular imaging devices, this invention proposes a vascular imaging method and system based on near-infrared light. The method specifically includes the following steps:
[0033] The test area is uniformly illuminated using a combination of 770nm+850nm+900nm light sources. Then, an image of the reflected near-infrared light is acquired using a camera with a filter. The image undergoes noise reduction and anti-flickering preprocessing to obtain an initial black-and-white image with varying shades. In the black-and-white image, veins and arteries are darker, while the surrounding tissues are lighter.
[0034] The black and white image is then transmitted to the image processing module for image contrast enhancement algorithm to process the image and obtain an enhanced image, making the vein and artery features more obvious.
[0035] Then, a model is trained using deep learning to segment the image, obtain the blood vessel image for projection, and remove the image of the surrounding tissue.
[0036] Finally, the vascular image is projected onto the corresponding position of the tested area through the optomechanical module and the projection module.
[0037] Since the choice of light source type affects the initial image quality, the types of light sources were first compared and referenced during the process of this invention. Currently, there are three main types of near-infrared light sources on the market: 1. Incandescent lamps, which can produce near-infrared light, but the amount produced is very small and insufficient for near-infrared imaging; 2. Infrared laser diodes (LDs), which have good directionality and monochromaticity, but their brightness is very high. Excessive brightness can cause severe exposure, and infrared laser diodes emit coherent light, which can cause interference between adjacent infrared laser diodes. These factors are not conducive to imaging; 3. Infrared light-emitting diodes (LEDs), which meet the requirements of this invention for suitable brightness, low power consumption, small size, and uniform illumination, which is conducive to forming conditions for easily eliminated uniform flicker.
[0038] Infrared LEDs typically have a certain divergence angle and cannot scatter light uniformly. We can solve this problem by installing an optical diffuser.
[0039] In the development of vascular imaging equipment, the selection and combination of different light sources play a decisive role in the imaging effect. The absorption capacity of deoxyhemoglobin (venous blood) and oxyhemoglobin (arterial blood) in human blood differs significantly, as shown in their light absorption characteristic curves. Figure 4 As shown. According to Figure 4 The advantages and disadvantages of different wavelengths, as well as the imaging effects of different light source combinations and single light sources, were compared, and a suitable light source was finally combined: 770nm + 850nm + 900nm.
[0040] To verify the imaging effect of the combined light source, such as Figure 5 As shown, the hands of individuals with thicker fat deposits or darker skin were selected as the test sites. Figure 5 In A, photography was conducted without a near-infrared light source. Figure 5 In section B, an 850nm light source was used for imaging. Figure 5 C was photographed using an 850nm+900nm light source. Figure 5 In image D, images were taken using 770nm+850nm+900nm wavelengths, with all light sources providing uniform illumination, resulting in an image quality as shown. Figure 5 As shown, in images using the combined light source of this invention, veins are more clearly visible, and veins that were not visible in previous images are also apparent. Therefore, the combined light source of this invention provides better vascular imaging results compared to other single or combined light sources.
[0041] When a combination of light sources is used to uniformly illuminate the area being measured, the camera can capture an initial image of the area being measured, such as... Figure 6As shown. The initial image cannot be directly used for projection and needs to be enhanced by an image processing module, mainly using a contrast enhancement algorithm. The enhanced image after processing by the image processing module is shown below. Figure 7 As shown. The enhanced image is obtained by training a model to segment the image and finally obtain a blood vessel image for projection, as shown in the figure. Figure 8 As shown. Finally, the vascular image is projected onto the tested area so that the vascular image coincides with the blood vessel, as shown. Figure 9 As shown.
[0042] A near-infrared light-based vascular imaging system, used to implement the method of the present invention, has the following structure: Figure 10 As shown, the system includes a light source control module, an image processing module, an optical engine module, a projector 100, a camera 200, a filter 300, a housing 600, and a combined light source 500. The projection light path of the projector 100 and the shooting light path of the camera 200 are perpendicular to each other. The bottom of the camera 200 is provided with a housing 600 with a right-angled trapezoidal cross-section, and the bottom of the housing 600 is provided with a plane mirror-type filter 300 at a 45-degree angle. The projection light path of the projector 100, after being reflected by the filter 300, coincides with the shooting light path of the camera 200.
[0043] In this invention, to ensure that the combined light source of 770nm+850nm+900nm can uniformly illuminate the measured area and eliminate the defect of non-uniform flicker, a ring-shaped design is adopted, including an infrared light-emitting diode set on an optical diffuser plate and a ring-shaped optical diffuser plate. Furthermore, the system of this invention employs a mutually perpendicular arrangement of the projector 100 and the camera 200, ensuring that the imaging light path and the projection light path overlap after passing through the filter 300. This effectively improves the internal spatial layout of the vascular imaging device, making it more compact and convenient.
[0044] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for vascular imaging based on near-infrared light, characterized in that, Includes the following steps: The test area is uniformly illuminated by a combination of 770nm+850nm+900nm light sources. Then, the near-infrared light reflected from the test area is captured and preprocessed to obtain the initial image. The initial image is enhanced to obtain an enhanced image; The enhanced image is segmented to obtain a blood vessel image for projection; The vascular image is projected onto the corresponding location of the area being tested.
2. The near-infrared light-based vascular imaging method according to claim 1, characterized in that, The preprocessing step involves denoising and removing uniform flicker from the image to obtain an initial black and white image.
3. The near-infrared light-based vascular imaging method according to claim 1, characterized in that, In image enhancement, an image contrast enhancement algorithm is used to enhance the image.
4. The near-infrared light-based vascular imaging method according to claim 1, characterized in that, In image segmentation, a deep learning training model is used for image segmentation.
5. The near-infrared light-based vascular imaging method according to claim 1, characterized in that, The combined light source includes a ring-shaped optical diffuser and multiple infrared light-emitting diodes disposed on the optical diffuser.
6. A near-infrared light-based vascular imaging system for implementing the near-infrared light-based vascular imaging method according to any one of claims 1-5, comprising a light source control module, a combined light source, an image processing module, an optomechanical module, a projector, a camera, a filter, and a housing; The light source control module controls the combined light source to emit near-infrared light of 770nm+850nm+900nm and illuminate the part to be measured; the camera acquires the image of the near-infrared light reflected from the part to be measured and performs preprocessing to obtain the initial image. The image processing module enhances the initial image to obtain an enhanced image; then, it segments the enhanced image to obtain a blood vessel image for projection. The optomechanical module controls the projection module to project the blood vessel image onto the corresponding position of the tested area.
7. The near-infrared light-based vascular imaging system according to claim 6, characterized in that, The projection light path of the projector is perpendicular to the shooting light path of the camera; the bottom of the camera is provided with a housing with a right trapezoidal cross-section; the bottom of the housing is provided with a plane mirror-type filter at a 45-degree angle; the projection light path of the projector coincides with the shooting light path of the camera after being reflected by the filter.