CN111401097A - Biological characteristic image acquisition device and access control system - Google Patents

Abstract

The embodiment of the application discloses a biological characteristic image acquisition device and an access control system. The acquisition device is a non-contact acquisition device and comprises a light blocking plate, a light source and a light source, wherein the light blocking plate is arranged on the inner side of a door and is provided with a first small hole for small hole imaging; the door is provided with a light-transmitting part corresponding to the first small hole; the image sensor is arranged on one side of the light blocking plate, which is back to the door; light rays on a target object with biological characteristics on the outer side of the door sequentially penetrate through the light transmission part and the first small hole and are projected onto the image sensor, so that the image sensor collects biological characteristic images of the target object. The collection system in the technical scheme can be arranged on the inner side of the door, so that people or objects on the outer side of the door are prevented from being damaged. In addition, the influence of the thickness of the door on the acquisition device is small, the applicability is wide, and the definition of the acquired image is high.

Description

Biological characteristic image acquisition device and access control system

Technical Field

The application relates to the field of biological characteristic image acquisition equipment, in particular to an acquisition device of biological characteristic images. In addition, the application also relates to an access control system.

Background

General fingerprint access control system has mainly included fingerprint collection module, treater, liquid crystal display module, keyboard etc.. Wherein, fingerprint collection module mainly used gathers fingerprint feature's image. Referring to fig. 1, fig. 1 is a schematic structural diagram of a contact fingerprint acquisition module. The fingerprint collection module 900 includes a total reflection prism 91, a light source 92, an image sensor 93 and a housing 94. The user presses a finger on the collection surface 911 of the total reflection prism 91, and light emitted by the light source 92 passes through one right-angle surface of the total reflection prism 91, namely the first right-angle surface 912, is reflected by the finger pressed on the collection surface 911, then passes through the other right-angle surface of the total reflection prism 91, namely the second right-angle surface 913, and reaches the image sensor 93 arranged below the second right-angle surface 913. Further, the image sensor 93 captures a fingerprint feature image of a finger pressed against the capturing surface 911.

When such fingerprint collection module was applied to access control system, need set up outside the door to press the finger to gather user's fingerprint characteristic image on gathering face 911 through the user, and then verify whether the user has the authority of opening the door. However, since the fingerprint collection module needs to be disposed outside the door, it is easily damaged, which is a problem to be solved by those skilled in the art.

Disclosure of Invention

In order to solve the technical problem, the present application provides a novel biometric image capturing device so as to be installed inside a door, thereby avoiding being damaged by people or objects outside the door.

In a first aspect, the present application provides a device for acquiring a biometric image, which is applied to an access control system, the device is a non-contact acquisition device, and comprises:

the light blocking plate is arranged on the inner side of the door and provided with a first small hole for small hole imaging; the door is provided with a light-transmitting part corresponding to the first small hole;

the image sensor is arranged on one side of the light blocking plate, which is back to the door; light rays on a target object with biological characteristics on the outer side of the door sequentially penetrate through the light transmission part and the first small hole and are projected onto the image sensor, so that the image sensor collects biological characteristic images of the target object.

With reference to the first aspect, in a first possible implementation manner of the first aspect, a convex lens is further disposed between the light blocking plate and the image sensor; the light on the target object with biological characteristics on the outer side of the door sequentially penetrates through the light transmission part and the first small hole to form a light spot, and the convex lens projects the light spot onto the image sensor after the light spot is contracted.

With reference to the first aspect and the foregoing possible implementation manners, in a second possible implementation manner of the first aspect, the number of the first small holes on the light blocking plate is greater than or equal to 2.

With reference to the first aspect and the foregoing possible implementation manners, in a third possible implementation manner of the first aspect, a second small hole for small hole imaging is further formed in the light blocking plate, and a diameter of the second small hole is different from a diameter of the first small hole.

With reference to the first aspect and the foregoing possible implementations, in a fourth possible implementation of the first aspect, the number of the second small holes is greater than or equal to 2.

With reference to the first aspect and the foregoing possible implementations, in a fifth possible implementation manner of the first aspect, the collecting device is provided with a light source for illuminating the target object.

With reference to the first aspect and the possible implementations described above, in a sixth possible implementation of the first aspect, the light emitted by the light source propagates in the light-transmitting portion by total reflection; when the target is close to the outer surface of the light transmission part, total reflection propagation of light rays at the contact part of the target and the outer surface of the light transmission part is damaged to form diffuse reflection, and the light rays of the diffuse reflection sequentially pass through the light transmission part and the first small hole and are projected onto the image sensor.

In a second aspect, the present application provides an access control system, comprising a processor, and a device for acquiring a biometric image of any one of the first aspect;

the acquisition device is used for acquiring a biological characteristic image of a target object;

the processor is used for determining whether the user with the target object has the operation authority or not according to the biological characteristic image and a preset image.

The above-mentioned collecting device can be installed on the inside of the door, thus avoiding being damaged by people or things on the outside of the door. Simultaneously, different with the fingerprint collection module among the current access control system, foretell collection system is mainly based on the principle of aperture formation of image, so the thickness of the printing opacity portion of door is very little to this collection system's influence. That is, if the acquisition device is of a standardized size, its applicability in different application scenarios is also better. In addition, compared with the collecting surface in a common fingerprint collecting module, the light blocking plate in the collecting device has various forms, can be better attached to the inner surface of the light transmission part, and reduces interference of reflection, diffuse reflection and refraction light generated on the inner surface of the light transmission part on the definition of the biological characteristic image to a certain extent.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a conventional fingerprint acquisition module;

FIG. 2 is a schematic view of a conventional fingerprint acquisition module mounted to a door;

FIG. 3 is an enlarged partial view of M in FIG. 2;

FIG. 4 is a schematic view of a conventional fingerprint sensor module mounted on a door with a relatively large thickness;

FIG. 5 is a schematic structural diagram of a first implementation manner of the biometric image capturing apparatus according to the present application;

FIG. 6 is a schematic structural diagram of a second implementation manner of the biometric image capturing apparatus according to the present application;

FIG. 7 is a schematic structural diagram of a third implementation manner of the biometric image capturing apparatus according to the present application;

FIG. 8 is a schematic structural diagram of a fourth implementation manner of the biometric image capturing apparatus according to the present application;

fig. 9 is a schematic partial front view of a light-transmitting portion and a light-blocking plate in one implementation of the biometric image capturing apparatus of the present application;

FIG. 10 is a schematic partial front view of a light blocking plate according to one implementation of the biometric image capturing apparatus of the present application;

fig. 11 is a schematic structural diagram of an implementation manner of the access control system of the present application.

Description of reference numerals:

fig. 1 to 4:

a fingerprint acquisition module 900; a total reflection prism 91; collecting the surface 911; a first right angle face 912; a second right-angle face 913; a light source 92; an image sensor 93; a housing 94.

Fig. 5 to 11:

a light blocking plate 1; a first orifice 11; a second orifice 12; an image sensor 2; a door 3; a light transmitting portion 31; an outer surface 311 of the light-transmitting portion; an inner surface 312 of the light-transmitting portion; a convex lens 4; a target 5; a light source 6.

Detailed Description

The following provides a detailed description of the embodiments of the present application.

The fingerprint acquisition module of current access control system sets up in the outside of door, is destroyed easily. If direct with current access control system setting at the door inboard, need set up the printing opacity portion on the door, then set up the fingerprint collection module in the inboard of door. Please refer to fig. 2, fig. 2 is a schematic structural diagram of the fingerprint acquisition module disposed on the inner side of the door. Here, door 3 is provided with light-transmitting portion 31, and light-transmitting portion 31 penetrates through the thickness direction of door 3, so that light on the outside of door 3 can pass through light-transmitting portion 31 to the inside of door 3, and light on the inside of door 3 can also pass through light-transmitting portion 31 to the outside of door 3. The collecting surface 911 of the fingerprint collecting module is arranged to be attached to the inner surface of the light-transmitting part 31, so that the collecting surface 911 corresponds to the light-transmitting part 31.

When collecting the fingerprint feature image, the user presses a finger on the outer surface 311 of the light-transmitting portion, the light emitted by the light source 92 passes through the first right-angle surface 912 of the total reflection prism 91 and the light-transmitting portion 31, is reflected by the finger pressed on the outer surface 311 of the light-transmitting portion, passes through the light-transmitting portion 31 and the second right-angle surface 913 of the total reflection prism 91, and reaches the image sensor 93 arranged obliquely below the second right-angle surface 913. Further, the image sensor 93 captures a fingerprint characteristic image of a finger pressed against the outer surface 311 of the light-transmitting portion.

Since the light passes through the light-transmitting portion 31 in addition to the total reflection prism 91, the light path in the whole capturing process is extended, which results in that the image sensor 93 may not capture the complete fingerprint feature image, especially in the case that the thickness d of the light-transmitting portion 31 is relatively thick. As shown in fig. 4, since thickness d of light-transmitting portion 31 in fig. 4 is larger than thickness d of light-transmitting portion 31 in fig. 3, the fingerprint feature image of a part of the finger pressed on outer surface 311 of the light-transmitting portion, as at B, cannot be captured by image sensor 93.

Based on this, when the thickness d of the light-transmitting portion 31 is different, in order to enable the image sensor 93 to collect a complete fingerprint feature image, the size of the fingerprint collection module needs to be changed accordingly. If the fingerprint collection module adopts standardized size, then the suitability of this fingerprint collection module in different application scenes is relatively poor.

In addition, because the inner surface 312 of the light-transmitting portion is difficult to be completely flat, and a gap exists between the collecting surface 911 of the fingerprint collecting module and the inner surface 312 of the light-transmitting portion, light from the light source 92 is reflected, diffusely reflected, and refracted on the inner surface 312 of the light-transmitting portion, which may cause serious interference to the definition of the finally collected fingerprint feature image. Referring to fig. 3, fig. 3 is an enlarged view of a portion M in fig. 2. As can be seen from fig. 3, the light ray b1 generates reflected, diffusely reflected light rays b1, b2, b3, and the like on the inner surface 312 of the light-transmitting portion. Where b1 overlaps the ray reflected at point a on the finger surface by ray a1, thereby affecting the imaging of the fingerprint at point a on the finger surface.

To this end, the present application proposes a new biometric image acquisition device that can be installed inside a door, does not need to be dimensionally changed according to the thickness of the door, and is suitable for use in an access control system.

Referring to fig. 5, fig. 5 is a schematic structural diagram of one implementation manner of the acquisition device of the present application. The acquisition device is a non-contact acquisition device and comprises a light blocking plate 1, wherein the light blocking plate 1 is arranged on the inner side of a door 3, and a first small hole 11 for small hole imaging is formed in the light blocking plate 1; the door 3 is provided with a light-transmitting part 31 corresponding to the first small hole 11; the image sensor 2 is arranged on one side of the light blocking plate 1, which is back to the door 3; the light on the target 5 with biological characteristics outside the door 3 passes through the light-transmitting portion 31 and the first small hole 11 in sequence, and is projected onto the image sensor 2, so that the image sensor 2 acquires a biological characteristic image of the target 5.

Each individual has a unique physiological characteristic or behavioral pattern, i.e., a biological signature, that can be measured or otherwise identified and verified. The biometric features may include physiological features such as fingerprints, faces, irises, palmprints, etc., as well as behavioral features such as gait, voice, handwriting, etc. Biological characteristics in this application primarily refer to physiological characteristics. That is, the biometric image in the present application is mainly an image representing physiological characteristics, such as a fingerprint characteristic image, a face characteristic image, a palm print characteristic image, an iris characteristic image, and the like.

The above-mentioned non-contact type capturing device is a capturing device that does not need to be in direct contact with an object (for example, a finger, a palm, or the like of a user) when capturing a biometric image.

Since the acquisition device of the present application is applied to an access control system, the inner side of the door 3 refers to the side of the door facing indoors; in contrast, the outer side of the door 3 refers to the side of the door facing outdoors.

Door 3 is provided with light transmission portion 31, and the shape of light transmission portion 31 may be any shape, which is not limited in the present application. The size of light-transmitting portion 31 generally needs to be larger than the size of first small hole 11.

In one example, a light-impermeable door, such as a stainless steel security door, may be provided with a through hole as the light-permeable portion. In practical applications, a general security door is usually provided with a peep hole, and the peep hole can be used as a light-transmitting portion or a component of the light-transmitting portion. In addition, a through hole similar to the through hole for installing the cat eye can be formed in the security door, and the through hole can be used as a light transmission part. The through hole can be filled with light-transmitting material.

In another example, the door may be made of a light-transmitting material (e.g., glass, etc.), and any one of the light-transmitting portions of the entire door may be considered as a light-transmitting portion. In other words, the door does not need to be additionally provided with a light-transmitting part, and is more suitable for collecting the biological characteristic image in a large area and a large range. For example, in the example shown in fig. 9, 5 fingers may be placed on the outer surface of light-transmitting portion 31 at the same time, so that biometric images of a plurality of fingers are simultaneously acquired over a wide range. For another example, the entire palm may be placed on the outer surface of light-transmitting portion 31 so as to capture a biometric image of the entire palm over a large area.

The light blocking plate 1 serves to block light from propagating from one side of the light blocking plate to the other. For example, the light blocking plate 1 itself may be made of a light blocking material, and is a flexible film. For another example, the light blocking plate 1 may include a substrate, and a layer of light blocking film disposed on the substrate. The substrate of the light blocking plate 1 and the light blocking film may be integrated or may be separate independent components. For example, in one implementation, the light blocking material may be sprayed directly onto the inner surface 312 of the light transmitting portion to form a light blocking film, and the substrate may be attached to the light blocking film. The specific structure of the light blocking plate is not limited in the present application.

The first small hole 11 is a small hole for small hole imaging, and may be any shape, and the specific shape and size may be different according to different application scenarios, which is not limited in the present application. For example, in one example, the first aperture 11 may be circular and may have a diameter of 5 microns to 50 microns.

The light blocking plate 1 is arranged on the inner side of the door, so that the first small hole 11 on the light blocking plate 1 is aligned with the position of the light transmitting part. An image sensor 2 is arranged on the side of the light-blocking plate 1 facing away from the door 3. Thus, the light on the target 5 outside the door 3 can pass through the light-transmitting portion 31 and the first small hole 11 in sequence and be projected onto the image sensor 2, so that the image sensor 2 can acquire the biometric image of the target 5.

Since the acquisition device is a non-contact acquisition device, the object may or may not be in contact with the outer surface of the light-transmitting portion of the door when acquiring the biometric image of the object. In different practical application scenes, when different target objects are faced, contact acquisition or non-contact acquisition can be selected according to practical situations. For example, in the examples shown in fig. 5 to 7, the palm of the user does not contact the outer surface of the translucent portion when the biometric image is captured. In the actual collecting process, the palm of the user can also be contacted with the outer surface of the light transmission part. For another example, when a human face is captured, the human face may not contact the outer surface of the light-transmitting portion. Also for example, when taking a fingerprint, a finger may be in contact with the outer surface of the light-transmissive portion.

It should be noted that the light on the target in the present application may be light emitted by the target itself, or light reflected and scattered from the surface of the target, which is not limited in the present application.

The above-mentioned collecting device can be installed on the inside of the door, thus avoiding being damaged by people or things on the outside of the door. Simultaneously, different with the fingerprint collection module among the current access control system, foretell collection system is mainly based on the principle of aperture formation of image, so the thickness of the printing opacity portion of door is very little to this collection system's influence. That is, if the acquisition device is of a standardized size, its applicability in different application scenarios is also better. In addition, compared with the collecting surface in a common fingerprint collecting module, the light blocking plate in the collecting device has various forms, can be better attached to the inner surface of the light transmission part, and reduces interference of reflection, diffuse reflection and refraction light generated on the inner surface of the light transmission part on the definition of the biological characteristic image to a certain extent.

The light from a point C on the object 3, after passing through the light-transmitting portion 3 and the first aperture 11, forms a light spot on the image sensor 2. If the light spot is too large, the light spot overlaps with light spots formed by light rays at other points, and therefore the definition of the biometric image is affected. Generally, if the aperture of the first small hole 11 is larger, the formed light spot is correspondingly larger, thereby affecting the definition of the biometric image. If the first small hole 11 is particularly small, the amount of light entering through the first small hole 11 is too small, i.e., the amount of light energy captured is too small, resulting in difficulty in imaging. Also, when the first pinhole 11 is too small, light diffraction becomes severe, and similarly, image clarity is reduced.

In order to solve the problem of balancing the sharpness and the amount of light entering the biometric image, a convex lens may optionally be provided between the light blocking plate and the image sensor. Referring to fig. 6, in one implementation, a convex lens 4 is disposed between the light blocking plate 1 and the image sensor 2; light rays on the target object 5 with biological characteristics on the outer side of the door 3 sequentially pass through the light-transmitting part 31 and the first small hole 11 to form light spots, and the light spots are contracted by the convex lens 4 and then projected onto the image sensor 2.

The light beam at one point C of the target 5 passes through the light-transmitting portion 31 and the first small hole 11 in this order to form a light spot. If the convex lens 4 is not provided, the image spot of the light spot on the image sensor 2 is C'. If the convex lens 4 is provided, the light spot is reduced by the convex lens 4, and the image spot on the image sensor 2 becomes C "smaller than C'. Therefore, the overlapping of the image spots formed at different points on the target object 5 is reduced, and meanwhile, the method does not need to reduce the aperture of the first small hole 11, so that the light incoming amount of the first small hole 11 is ensured, the light diffraction is reduced, and the definition of the biological characteristic image is improved on the whole.

Optionally, the number of the first small holes 11 on the light blocking plate 1 is more than or equal to 2. By arranging the plurality of first small holes 11, the biological characteristic images of different areas of the target object can be acquired simultaneously and respectively, or the biological characteristic images of different target objects can be acquired, or the biological characteristic images of different angles of the same target object can be acquired.

For example, referring to fig. 9, 5 first small holes 11 are formed in the light blocking plate 1, and a user places five fingers of a hand on the outer surface of the light transmitting portion 31 of the door 3, and the five fingers are respectively aligned with the 5 first small holes 11, so that the image sensor can simultaneously acquire fingerprint feature images of the five fingers. For example, the plurality of first pinholes 11 may be used to respectively acquire local feature images of the palm print features of the user, and then the plurality of local feature images are spliced to obtain a complete palm print feature image.

In addition, if part of the first small holes 11 are not covered by the target when the biometric image is acquired, these first small holes 11 can also be used as light inlet holes to supplement the light inlet amount.

The requirements for acquiring a biometric image may differ for different objects. For example, generally, the definition of the fingerprint feature image is required to be higher than that of the face feature image, so that a small hole with a smaller diameter is required for collecting the fingerprint feature image, and a small hole with a larger diameter can be used for collecting the face feature image.

Therefore, referring to fig. 10, the light blocking plate is further provided with a second small hole 12 for small hole imaging, and the diameter of the second small hole 12 is different from the diameter of the first small hole 11.

The second aperture 12 is an aperture for imaging an aperture, and may be any shape, and the specific shape and size may be different according to different application scenarios, which is not limited in the present application. For example, in one example, the second apertures 12 may be circular and may have a diameter of 5 microns to 50 microns.

The number of the second small holes 12 is 1 or more. When the number of the second small holes 12 is larger than or equal to 2, the biological characteristic images of different areas of the target object, or the biological characteristic images of different target objects, or the biological characteristic images of different angles of the same target object can be acquired simultaneously and respectively. For example, when the second apertures 12 are used to collect facial image features, the plurality of second apertures 12 may collect facial feature images of the same user from different angles, so that facial feature images of different angles of the user may be obtained, so as to form a 3D facial feature image by using the images subsequently.

Through setting up the second aperture 12 different with first aperture 11 diameter to make this collection system can be applicable to more gathering the biological characteristic image of multiple different grade type, the suitability is wider. For example, the first pinhole 11 may be used to collect a fingerprint feature image, and the second pinhole 12 may be used to collect a face feature image. The first small hole 11 and the second small hole 12 may respectively correspond to the image sensors, or may share the image sensor 2. When the image sensor 2 is shared, the structure of the acquisition device can be simplified, and the manufacturing cost of the acquisition device can be reduced.

It should be noted that if the image sensor 2 is a very precise image sensor, the same size of the holes can be used for collecting the biometric images of different objects, for example, collecting the face feature image and collecting the fingerprint feature image, i.e. the diameter of the first hole can be the same as the diameter of the second hole.

Optionally, a light source for illuminating the target object may be further provided in the collecting device. The light source irradiates, so that the intensity of reflected and scattered light of the target object is higher, and the image sensor is favorable for acquiring clearer biological characteristic images. For example, referring to fig. 7, in one implementation, the light source 6 may be disposed on a surface of the light blocking plate 1 facing the light transmitting portion 31, so that light emitted from the light source 6 can pass through the light transmitting portion 31 to reach the target 5 to illuminate the target 5.

Some of the light emitted from the light source 6 may be reflected and scattered by the inner surface 312 of the light-transmitting portion, and the light may interfere with the light passing through the light-transmitting portion 31 on the target 5, thereby affecting the sharpness of the picture captured by the image sensor 2.

For this reason, in one implementation, the light source 6 may be disposed flush with the surface of the light blocking plate 1 facing the light transmitting portion 31, thereby reducing the gap between the light blocking plate 1 and the inner surface 312 of the light transmitting portion, and further reducing the reflection and scattering effects of the inner surface 312 of the light transmitting portion on the light source light.

In another implementation, referring to fig. 8, the light source may be disposed at a side of the light blocking plate 1, and the light emitted from the light source 6 propagates in the light transmitting portion 31 by total reflection. When the target 5 is close to the outer surface 311 of the light transmission part, the total reflection propagation of the light rays at the contact part of the target 5 and the outer surface 311 of the light transmission part is destroyed to form diffuse reflection, and the light rays of the diffuse reflection sequentially pass through the light transmission part 31 and the first small hole 11 to be projected onto the image sensor 2, so that the biological characteristic image B '-A' of the target A-B area is collected.

In this way, it is not necessary to dispose the light source 6 between the light blocking plate 1 and the door 3, thereby preventing the reflection and scattering action of the inner surface 312 of the light transmitting portion from affecting the sharpness of the biometric image. Part of the light emitted by the light source 6 propagates in the light transmission part 31 in a total reflection manner, and the rest of the light which does not propagate in the total reflection manner is consumed in the light transmission part 31 along with the propagation, so that the part of the light does not influence the definition of the object characteristic image.

In a second embodiment of the present application, an access control system is provided. Referring to fig. 11, the access control system includes a processor and a device for acquiring a biometric image according to any one of the first embodiments; the acquisition device is used for acquiring a biological characteristic image of a target object; the processor may be connected to the image sensor 2, and configured to determine whether the user with the target object has an operation right according to the biometric image and a preset image.

The collecting device can be referred to the description of the first embodiment, and the description thereof is omitted here.

The preset image is a biometric image which is pre-entered into a processor of the access control system by a user. The preset image may also be acquired in advance by the acquisition means. If it is not

When the similarity between the newly acquired biometric image and the preset image is within the preset threshold range, it can be determined that the current user with the target object has operation authority, such as unlocking a door lock. If the similarity is out of the preset threshold range, judging that the current user with the target object does not have the operation authority, for example, the door lock is not opened.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

The same and similar parts in the embodiments in this specification may be referred to one another, and different implementations may be combined with one another on the premise that logics are not contradictory to one another. The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention.

Claims (8)

1. The utility model provides an acquisition device of biological characteristic image, is applied to access control system, its characterized in that, acquisition device is non-contact acquisition device, includes:

the light blocking plate is arranged on the inner side of the door and provided with a first small hole for small hole imaging; the door is provided with a light-transmitting part corresponding to the first small hole;

the image sensor is arranged on one side of the light blocking plate, which is back to the door; light rays on a target object with biological characteristics on the outer side of the door sequentially pass through the light transmission part and the first small hole and are projected onto the image sensor, so that the image sensor collects biological characteristic images of the target object.

2. The acquisition device according to claim 1, wherein a convex lens is further disposed between the light blocking plate and the image sensor; the light on the target object with biological characteristics on the outer side of the door sequentially penetrates through the light transmission part and the first small hole to form a light spot, and the convex lens projects the light spot onto the image sensor after the light spot is contracted.

3. The collection device of claim 1, wherein the number of the first small holes on the light blocking plate is greater than or equal to 2.

4. The acquisition device according to claim 1, wherein the light blocking plate is further provided with a second small hole for small hole imaging, and the diameter of the second small hole is different from that of the first small hole.

5. The collecting device as claimed in claim 4, wherein the number of the second small holes is more than or equal to 2.

6. The acquisition device according to claim 1, characterized in that it is provided with a light source for illuminating the object.

7. The collecting device according to claim 6, wherein the light emitted from the light source propagates in the light-transmitting portion by total reflection; when the target is close to the outer surface of the light transmission part, total reflection propagation of light rays at the contact part of the target and the outer surface of the light transmission part is damaged to form diffuse reflection, and the light rays of the diffuse reflection sequentially pass through the light transmission part and the first small hole and are projected onto the image sensor.

8. An access control system comprising a processor and the biometric image capture device of any one of claims 1-7;

the acquisition device is used for acquiring a biological characteristic image of a target object;

the processor is used for determining whether the user with the target object has the operation authority or not according to the biological characteristic image and a preset image.

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