Palm prosthesis suitable for infrared detection

Abstract

A palm prosthesis suitable for infrared detection is characterized in that the palm prosthesis comprises a skin imitation body which has a scattering effect on infrared light; the vein imitation body is located in the skin imitation body; and the surface film layer is positioned on the surface of the skin imitation body and is provided with textures. According to the utility model, through imaging, a vein imaging effect close to a real palm can be realized, and the vein imaging effect of an optical system can be quantitatively evaluated.

Description

TECHNICAL FIELD

[0001] The utility model relates to palm detection technical field, specifically, relate to a kind of palm prosthesis suitable for infrared detection. BACKGROUND

[0002] As a new biometric technology, palm vein recognition is widely promoted due to its non-contact, high anti-counterfeiting and high precision. In palm vein recognition technology, vein imaging quality is particularly important. However, the vein features are distributed inside the palm, and the reflection of the palm surface light can easily interfere with the vein imaging and add image noise. Therefore, it is usually considered to introduce polarized light imaging to filter out the palm surface reflection light and suppress noise. The polarization performance of the imaging system is directly related to the final vein imaging effect, so an objective evaluation device is needed to evaluate the polarization imaging performance of the system.

[0003] For palm detection, RGB camera is usually used to collect palmprint image, or infrared camera is used to collect palm vein image under the skin, or both types of cameras are used for collection. However, the existing vein prosthesis scheme has certain differences with the real palm vein, cannot simulate the collection process of RGB camera or infrared camera, and the evaluation effect of the vein imaging performance of the palm vein imaging system is limited, so some improvements need to be made to optimize the phantom.

[0004] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical scheme of the utility model, and it does not necessarily belong to the prior art of the present patent application. In the absence of explicit evidence that the above content has been disclosed on the filing date of the present patent application, the above background technology should not be used to evaluate the novelty and inventiveness of the present application. UTILITY MODEL CONTENT

[0005] Therefore, the utility model uses skin phantom, vein phantom and surface film layer to simulate the palm state during non-contact detection, and through imaging of the invention, the vein imaging effect close to the real palm can be realized, and the vein imaging effect of the optical system can be quantitatively evaluated to solve the deficiency in the prior art.

[0006] The utility model provides a kind of palm prosthesis suitable for infrared detection, it is characterized by comprising:

[0007] The skin phantom has scattering effect on infrared light;

[0008] The vein phantom is located in the skin phantom;

[0009] The surface film layer is located on the surface of the skin phantom and has texture.

[0010] Optionally, the palm prosthesis for infrared detection has the skin simulator made of silicone or latex.

[0011] Optionally, the palm prosthesis for infrared detection has the vein simulator with at least two points having different distances from the surface of the skin simulator.

[0012] Optionally, the palm prosthesis for infrared detection has the vein simulator including a first vein simulator and a second vein simulator, and the first vein simulator and the second vein simulator have different widths.

[0013] Optionally, the palm prosthesis for infrared detection has the first vein simulator and the second vein simulator having different distances from the surface of the skin simulator.

[0014] Optionally, the palm prosthesis for infrared detection has the surface film layer made of low-density polyethylene, low-density polypropylene, low-density polyurethane or other low-density synthetic material.

[0015] Optionally, the palm prosthesis for infrared detection has the surface film layer with a texture formed by pressing.

[0016] Optionally, the palm prosthesis for infrared detection has the surface film layer with a transmittance of infrared light not less than 30%.

[0017] Optionally, the palm prosthesis for infrared detection has the vein simulator capable of absorbing infrared light, and the vein simulator has different infrared waveband reflectivity from the skin simulator.

[0018] Optionally, the palm prosthesis for infrared detection has the vein simulator having a distance of [5mm, 8mm] from the surface of the skin simulator.

[0019] Compared with the prior art, the palm prosthesis for infrared detection has the following beneficial effects:

[0020] In the palm prosthesis for infrared detection, the vein simulator is arranged in the skin simulator, the skin simulator has a scattering effect on infrared light, the process of infrared light penetrating the skin and irradiating the vein can be well simulated, and the vein imaging simulation is higher.

[0021] The surface film layer is arranged on the surface of the skin phantom, has specific reflectivity and transmittance in the infrared light band, and has texture; can well simulate the noise interference caused by the reflection of the palm print on the skin surface to the infrared light and the process of the infrared light penetrating the surface skin into the subcutaneous tissue; and can well simulate the image noise caused by the surface palm print in the palm vein imaging.

[0022] The utility model discloses the detection standardization to imaging system, and the imaging performance and polarization performance of imaging system can be quantitatively evaluated.

[0023] The utility model discloses when testing, need not artificial experience judgment, can quantitatively, and the vein imaging effect evaluation of palm vein imaging system is more accurate. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will briefly introduce the drawing needed to be used in the embodiment or prior art description, obviously, the drawing in the following description is only the embodiment of the utility model, and for the ordinary skilled person in the art, under the premise of not paying the creative labor, still can obtain other drawings according to the provided drawing. Through reading the detailed description of the following non-restrictive embodiment with reference to the drawings, other features, purposes and advantages of the utility model will become more obvious:

[0025] Figure 1 It is a structure schematic view of a palm phantom suitable for infrared detection in the embodiment of the utility model;

[0026] Figure 2 It is a polarization camera detection schematic view in the embodiment of the utility model;

[0027] Figure 3 It is a palm phantom imaging schematic view of a non-polarization optical system in the embodiment of the utility model;

[0028] Figure 4 It is a palm phantom imaging effect schematic view of a polarization optical system in the embodiment of the utility model;

[0029] Figure 5 It is a vein position gray scale distribution curve of the palm phantom imaging of the non-polarization optical system in the embodiment of the utility model;

[0030] Figure 6 It is a vein position gray scale distribution curve of the palm phantom imaging of the polarization optical system in the embodiment of the utility model.

[0031] 1-infrared transmitting end;

[0032] 2-infrared receiving end;

[0033] 3 - Parallel polarizer;

[0034] 4 - Perpendicular polarizer;

[0035] 5 - Surface film layer;

[0036] 6 - Vein phantom;

[0037] 7 - Skin phantom; DETAILED DESCRIPTION

[0038] The utility model will be described in detail below in combination with specific embodiments. The following examples will help the person skilled in the art to further understand the utility model, but do not limit the utility model in any form. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the utility model, a number of variations and improvements can be made. These all belong to the protection scope of the utility model.

[0039] The terms "first", "second", "third", "fourth" and the like in the description and claims of the utility model and the above-mentioned drawings (if any) are used to distinguish similar objects, and do not have to be used to describe a specific order or chronological order. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the utility model described herein, for example, can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] The palm prosthesis suitable for infrared detection provided by the utility model embodiment aims at solving the problems in the prior art.

[0041] The technical solutions of the utility model and how the technical solutions of the application solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described again in some embodiments. The embodiments of the utility model will be described below with reference to the drawings.

[0042] In the utility model, the vein phantom is arranged in the skin phantom, and the skin phantom has a scattering effect on infrared light, which can well simulate the process that infrared light penetrates the skin and irradiates the vein, and the vein imaging simulation is higher; the surface film layer is arranged on the surface of the skin phantom, has a specific reflectivity and transmittance in the infrared light wave band, and has a texture, which can well simulate the reflection of the palm surface and the penetration of infrared light into the subcutaneous tissue.

[0043] Figure 1 It is a structure diagram of a palm prosthesis suitable for infrared detection in the embodiment of the present application. As shown in the figure, the palm prosthesis suitable for infrared detection in the embodiment of the present application comprises: Figure 1

[0044] The skin simulator 7 has a scattering effect on infrared light.

[0045] Specifically, the skin simulator is the main structure of the palm prosthesis, mainly simulating the skin characteristics of a real human palm. It has a scattering effect on infrared light, which is to simulate the performance of real skin under infrared light, so that the palm prosthesis can exhibit similar features to a real palm in infrared detection. In order to achieve the scattering effect of infrared light, the skin simulator is usually made of materials with scattering properties. Since only palm prints and vein information under the skin are usually collected when detecting the palm, this embodiment does not need to completely simulate the structure of the palm, but only needs to simulate the epidermis and part of the subcutaneous tissue. The skin simulator in this embodiment has a certain thickness, which is greater than the depth that infrared light can penetrate.

[0046] The vein simulator 6 is located in the skin simulator.

[0047] Specifically, the vein simulator is located in the skin simulator, mainly simulating the internal vein network of a real palm. It is one of the most critical parts of the palm prosthesis, because the vein recognition technology mainly relies on the recognition of the vein network. It should be noted that the vein simulator is used to simulate the characteristics of the vein, but does not need to simulate the distribution, direction, etc. of the vein. The absorption and reflection characteristics of the vein simulator to infrared light are different from those of the skin simulator, so that a clear vein image can be presented under infrared light. At the same time, these materials also need to have good stability and durability to ensure that they do not change when used for a long time or in contact with different environments.

[0048] The surface film layer 5 is located on the surface of the skin simulator and has texture.

[0049] Specifically, the surface film layer is located on the surface of the skin simulator, which can penetrate infrared light and provide texture. The surface film layer has fine texture, which imitates the texture characteristics of the real palm skin. The texture can simulate the reflection characteristics of the real palm in infrared detection. Different reflectivity and texture characteristics of the film layer will result in different reflection effects, thereby affecting the final infrared image. The texture can also be used to detect the shooting effect of the RGB camera.

[0050] ​In some embodiments, the skin phantom is made of silicone or latex. Silicone is a highly elastic synthetic material that offers good flexibility and durability. Silicone has a moderate scattering effect on infrared light, which can simulate the performance of real skin under infrared light. Studies have shown that as the concentration of glycerol increases, the scattering coefficient of silicone decreases, which helps to increase the depth of light penetration, so the appropriate silicone with a scattering coefficient can be selected according to the intensity of the infrared light being tested. Silicone is easy to process into various shapes and sizes, suitable for the manufacture of complex structures, such as palm prostheses containing fine blood vessel structures. Silicone skin phantom performs well in terms of wear resistance, aging resistance, and has a long service life. Latex is a natural or synthetic rubber material that has some elasticity and softness. The scattering effect of latex on infrared light may vary depending on the material formula and process, so it is necessary to select a formula and process with appropriate scattering characteristics. Latex material is relatively low in price, suitable for mass production and application. Silicone skin phantom is generally superior to latex skin phantom in terms of wear resistance and aging resistance. Cost: The production cost of latex skin phantom is relatively low, suitable for mass production and application; while the cost of silicone skin phantom is relatively high due to the high cost of materials and complex processing. Both silicone and latex are safe and non-toxic materials.

[0051] In some embodiments, the vein phantom has at least two points with different distances from the surface of the skin phantom. Vein phantom in palm prosthesis is not a simple planar structure, but has a three-dimensional form and complex layout. This means that different parts of the vein phantom (i.e. different points or areas) have different distances from the surface of the skin phantom. This design can simulate the depth variation of real veins in the palm, thereby increasing the realism and recognition accuracy of the prosthesis under infrared detection. Vein phantom is usually made of materials with specific absorption characteristics, such as anhydrous copper sulfate, which can simulate the absorption effect of real veins on infrared light. In the design of vein phantom, at least two points (or areas) have different distances from the surface of the skin. This means that in some parts, the vein phantom is closer to the skin surface, while in other parts it is relatively deeper. This design can simulate the varying depth of real palm veins, as the depth of veins in actual palms also varies due to individual differences. By making the vein phantom have different distances from the skin surface, a more realistic palm vein structure can be simulated. In infrared detection, vein recognition technology relies on accurate identification of vein vascular networks. The three-dimensional form and distance difference of the vein phantom help to conduct a more comprehensive test. If the vein phantom is a simple planar structure or all points have the same distance from the surface of the skin phantom, it will be difficult to simulate the characteristics of real palm veins, thereby reducing the comprehensiveness of the test.

[0052] In some embodiments, the vein phantom includes a first vein phantom and a second vein phantom; the first vein phantom and the second vein phantom have different widths. This embodiment simulates the diversity of veins in a real palm. The vein vascular network in a real palm is composed of veins with different widths and depths. By setting different widths for the vein phantom, this diversity can be more accurately simulated, thereby increasing the realism and credibility of the prosthesis. The vein phantom is composed of at least two parts, namely the first vein phantom and the second vein phantom. These two parts simulate different vein regions in a real palm, respectively. The first vein phantom and the second vein phantom have different widths. This design can simulate the change in vein width in a real palm, because in an actual palm, the vein width in different parts will also be different. Since the vein characteristics of different people's palms differ, including vein width, depth, and distribution, etc. By setting different widths for the vein phantom, it can be more adapted to the characteristics of different people's palms, improving the universality and adaptability of the prosthesis.

[0053] In some embodiments, the first vein phantom and the second vein phantom have different distances from the surface of the skin phantom. The vein vascular network in a real palm has a complex three-dimensional layout, with different veins located at different depth levels. By setting different depths (i.e. distances from the surface of the skin phantom) for the first vein phantom and the second vein phantom, the sense of hierarchy and depth of this real vein structure can be more accurately simulated. In infrared detection, vein recognition technology relies on accurate identification of the vein vascular network. Vein phantoms of different depths help infrared detection devices more accurately capture and identify vein characteristics.

[0054] In some embodiments, the surface film layer is low-density polyethylene, low-density polypropylene, low-density polyurethane, or other low-density synthetic materials. Low-density polyethylene (LDPE) is a soft, translucent plastic material with good chemical resistance and electrical insulation. It can be processed into films, pipes, and various shaped products through methods such as blow molding, extrusion, and injection molding. Due to its excellent flexibility and low-temperature resistance, LDPE is commonly used to make plastic bags, agricultural films, and food packaging materials. In addition, it can also be used as the insulation layer of electrical wires and cables, as well as artificial leather and other products. Low-density polypropylene (LDPP) is a thermoplastic resin with good heat resistance, chemical resistance, and mechanical strength. Compared with LDPE, LDPP has a higher melting point and hardness. Low-density polyurethane (LDPU) is a polymer generated by the reaction of isocyanate groups and polyols, with good elasticity and wear resistance. It can be made into rigid or soft foam plastics. In addition to the three common low-density synthetic materials mentioned above, there are many other types of low-density synthetic materials, such as polystyrene (PS), polycarbonate (PC), and polyamide (PA), etc. These materials each have their own characteristics and can be selected and applied according to specific needs.

[0055] In some embodiments, the surface film layer is textured by pressing. In the design of a palm prosthesis, the texture of the surface film layer is crucial for simulating the appearance of real skin and its effect on infrared light. Texturing by pressing can impart specific patterns, relief, or roughness to the surface film layer, making it more realistic and durable. The process of pressing texture typically involves placing the surface film layer material between a mold or a press roller, then applying certain pressure and temperature. The mold or press roller is engraved with a specific texture pattern, and when the material is subjected to pressure and temperature, it will deform according to the shape of the mold or press roller, thus forming a texture corresponding to the mold or press roller. Through the precise design of the mold or press roller, a texture very similar to real skin can be made, including details such as pores, wrinkles, fingerprints, etc. The texture formed by pressing usually has high wear resistance and tear resistance, which can resist wear and tear in daily use. The pressing process can usually be automated, which can greatly improve production efficiency and reduce production cost.

[0056] In some embodiments, the surface film layer has a transmittance of infrared light of no less than 30%. When the surface film layer has a transmittance of infrared light of no less than 30%, it can ensure that infrared light can effectively penetrate the surface film layer and interact with the internal vein phantom or other structures, so as to be accurately captured and identified by the infrared detection device. The surface film layer can have a transmittance of infrared light of 30%, 35%, 40%, 45%, 50% or any other unlisted value. The surface film layer with a specific transmittance can ensure that infrared light reaches the internal vein phantom, while also having the effect of surface texture reflection imaging; thereby improving the accuracy of palm vein imaging simulation.

[0057] In some embodiments, the vein phantom can absorb infrared light, and the infrared waveband reflectivity of the vein phantom is different from that of the skin phantom. The vein phantom is usually made of materials with specific optical properties, which can effectively absorb infrared light and have different effects on the infrared waveband than the skin phantom. By precisely controlling the composition and surface treatment of the material, the absorption rate of the vein phantom to infrared light can be adjusted to simulate the optical behavior of real veins at different wavelengths. The vein phantom can absorb infrared light, which helps to generate infrared images similar to real veins. This absorption characteristic can improve the authenticity and recognition accuracy of the prosthesis under infrared detection, especially when using transmission-type infrared imaging technology. In order to achieve effective infrared absorption, the vein phantom needs to use materials with high absorption rate, such as specific plastics or metal coatings.

[0058] In some embodiments, the distance between the vein phantom and the surface of the skin phantom is [5mm, 8mm]. In a real palm, the depth of the vein is not fixed, but there is a certain range of variation. This depth variation helps to distinguish different individuals and increases the security of biometric identification. By setting the vein phantom in the range of 5mm to 8mm, the depth variation similar to the real palm can be simulated, thereby improving the authenticity and identification accuracy of the prosthesis under infrared detection.

[0059] In some embodiments, the surface film layer is a polyethylene foam film (also known as EPE pearl cotton film); it is produced by physical foaming of low-density polyethylene plastic to generate countless independent bubbles, and then adding texture on the surface through a pressing process to simulate the optical effect of the skin on the palm surface. The surface film layer is attached to the skin phantom through the film coating process.

[0060] In some embodiments, the vein phantom is circular or elliptical to better simulate the characteristics of the vein.

[0061] Figure 2 A polarization camera detection schematic diagram in an embodiment of the present utility model. After the non-polarized light emitted by the infrared emission end 1 passes through the parallel polarizer 3, it becomes linearly polarized light; based on the imaging characteristics of palm veins, when the linearly polarized light hits the palm surface, the reflected light is still polarized light in the parallel direction, and after entering a certain depth of the palm, it is depolarized due to multiple scattering, and the light reflected at the vein position is unpolarized light.

[0062] After passing through the parallel polarizer 3, the linearly polarized light hits the surface film layer 5, part of the light is directly reflected by the film layer and still maintains the parallel polarization characteristic; another part of the light enters the skin phantom 7 inside, is reflected after hitting the vein phantom 6, and this part of the reflected light is depolarized and loses polarization. The surface film layer of the vein phantom 5 is made of low-density polyethylene plastic or other materials; the vein phantom 6 is made of two metal materials with different thicknesses and different embedding depths, which are used to simulate palm veins with different thicknesses and depths in a real palm; the skin phantom 7 is made of silicone material, which has scattering effect on infrared light, and is used to simulate the skin of the palm. The reflected light after passing through the vein phantom 6 reaches the vertical polarizer 4, at this time the reflected light reflected by the surface film layer 5 cannot pass through due to the vertical direction, while the reflected light reflected by the vein phantom 6 can pass through. After passing through the vertical polarizer 4, the polarized light enters the receiving end 2, at this time the receiving end receives the vein signal inside the vein phantom.

[0063] Using the palm prosthesis in the embodiment, the palm vein can be imaged in the infrared wave band, and the polarization performance of the imaging system can be effectively detected.

[0064] At the same time, based on the obtained vein picture, the vein imaging effect can be quantitatively evaluated through vein contrast calculation.

[0065] The following of the specification is described by taking two vein phantoms as an example, but those skilled in the art can understand that the number of vein phantoms can be any number. For any number of vein phantoms, it is within the protection scope of the utility model.

[0066] For Figure 3 and Figure 4 The vein prosthesis images are analyzed, a line segment spanning the two veins is drawn at the same position of the two pictures, and a gray scale distribution curve on the line segment is drawn;

[0067] As Figure 6 shown, it can be seen that the two veins correspond to two valley values in Figure 6 respectively; and for imaging at the same position of the prosthesis, the veins are almost indistinguishable in the non-polarized optical system, and the veins can be imaged more clearly in the polarized optical system. Figure 5

[0068] The contrast of the two veins at the position is calculated and analyzed:

[0069] Contrast = (I_max - I_min) / (I_max + I_min)

[0070] Wherein, I_max is the gray value of the background area, and I_min is the gray value of the vein position;

[0071] After imaging of the vein prosthesis by the non-polarized optical system, the contrast of the two veins is close to 0; in the polarized sheet optical system, the contrast of the left vein is 13.51%, and the contrast of the right vein is 29.90%. The higher the contrast, the better the imaging effect of the corresponding vein, which is beneficial to subsequent extraction of vein features.

[0072] By imaging the vein phantom, the vein contrast can be quantitatively calculated, and the polarization performance of the polarization type vein imaging system can be quantitatively evaluated.

[0073] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the various embodiments can be referred to each other. The above description of the disclosed embodiments enables those skilled in the art to implement or use the utility model. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the utility model. Therefore, the utility model will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

[0074] ​The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the specific embodiments described above, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which do not affect the essential content of the present application.

Claims

1. A prosthetic hand suitable for infrared detection, characterized in that, include: The skin-like body scatters infrared light. A vein phantom is located within the skin phantom. A surface film layer, located on the surface of the skin phantom, has a texture.

2. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The skin prosthetic is made of silicone or latex.

3. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The vein phantom has at least two points at different distances from the surface of the skin phantom.

4. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The vein phantom includes a first vein phantom and a second vein phantom; the first vein phantom and the second vein phantom have different widths.

5. A prosthetic hand suitable for infrared detection according to claim 4, characterized in that, The first vein phantom and the second vein phantom are at different distances from the surface of the skin phantom.

6. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The surface film is made of low-density polyethylene resin, low-density polypropylene resin, low-density polyurethane, or other low-density synthetic materials.

7. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The texture of the surface film is formed by pressing.

8. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The surface film has an infrared light transmittance of not less than 30%.

9. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The vein phantom can absorb infrared light, and the infrared reflectivity of the vein phantom is different from that of the skin phantom.

10. A prosthetic hand suitable for infrared detection according to claim 1, characterized in that, The distance between the vein phantom and the surface of the skin phantom is [5mm, 8mm].

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