Imaging system and intelligent door lock

Abstract

The invention discloses an imaging system and an intelligent door lock. The imaging system comprises a wide-angle image acquisition module, an iris image acquisition module, a light reflection control module and a processing module; the wide-angle image acquisition module comprises a wide-angle camera and at least one first light supplement unit, the iris image acquisition module comprises at least one iris camera and at least one second light supplement unit, the light reflection control module comprises a reflection unit and a control unit, and the reflection unit is located in a light path of the iris camera and the second light supplement unit. According to the intelligent door lock, the wide-angle camera is used for collecting the image in the view field range, and when the image collected by the wide-angle camera is provided with the human eyes, the distance between the human eyes and the intelligent door lock and the deflection angle of the human eye position relative to the optical axis of the wide-angle camera and / or the reflection unit are calculated according to the image data output by the wide-angle camera; the iris camera is controlled to change the view field range and the depth of field of imaging, so that human eyes can clearly image on the iris camera, and the iris recognition precision is improved.

Description

Technical Field

[0001] The present invention relates to the field of biometric identification technology, and in particular to an imaging system and a smart door lock. Background Art

[0002] Compared to traditional identification technologies (such as keys, passwords, and electronic tags), biometrics offer greater security, convenience, and versatility. Common biometric technologies include fingerprint, face, iris, and voice recognition. Iris recognition is a security detection technology that uses the iris in the eye for identity verification. The iris is the circular, textured area between the black pupil and the white sclera in the human eye. Numerous medical and computer science studies have shown that the iris texture varies from eye to eye and remains stable from eight months after embryonic formation. Therefore, the iris possesses the advantages of high uniqueness and stability. Furthermore, as an externally visible internal organ, the iris is non-invasive. These advantages make the iris particularly suitable for human authentication and identification, and it has been successfully used for identification in airports, customs, banks, and other settings.

[0003] However, due to the small area of ​​the human iris, existing iris cameras must use lenses with a large magnification ratio to obtain high-quality iris images that can be used for identification. This results in a small camera acquisition angle of view and a small ranging depth of field. It cannot actively adapt to the iris recognition and authentication needs of people of different heights and different measurement distances. Users are required to actively align their eyes with the imaging field of view of the iris camera, resulting in a poor user experience. This shortcoming limits the application of iris recognition in consumer scenarios such as home smart door locks. Therefore, how to solve the small measurement distance range and small measurement field of view of iris recognition is an urgent problem that needs to be solved. Summary of the Invention

[0004] Embodiments of the present invention provide an imaging system and a smart door lock. The imaging system is used in a smart door lock and uses a wide-angle camera to capture images within a field of view. When the image captured by the wide-angle camera contains a human eye, the system calculates the distance between the human eye and the smart door lock and the deflection angle of the human eye relative to the optical axis of the wide-angle camera and / or a reflective unit based on image data output by the wide-angle camera. The system then controls the iris camera to change the imaging field of view and depth of field so that the human eye can be clearly imaged on the iris camera, thereby improving iris recognition accuracy.

[0005] According to one aspect of the present invention, an imaging system is provided for use in a smart door lock. The imaging system includes a wide-angle image acquisition module, an iris image acquisition module, a light reflection control module, and a processing module. The wide-angle image acquisition module, the iris image acquisition module, and the light reflection control module are all connected to the processing module.

[0006] The wide-angle image acquisition module includes a wide-angle camera and at least one first fill light unit, the iris image acquisition module includes at least one iris camera and at least one second fill light unit, and the light reflection control module includes a reflection unit and a control unit, wherein the reflection unit is located in the optical path between the iris camera and the second fill light unit;

[0007] The wide-angle camera is used to capture images within the field of view and send the captured image data to the processing module. When the processing module detects that there is a human eye in the captured image through image processing, it calculates the distance between the human eye and the smart door lock and the deflection angle of the human eye relative to the optical axis of the wide-angle camera and / or the reflection unit based on the image data output by the wide-angle camera, controls the iris camera to start and drives the control unit to control the reflection unit to change the deflection angle of the reflection unit, thereby changing the field of view of the iris camera imaging and adjusting the depth of field of the iris camera so that the human eye can be clearly imaged on the iris camera. The iris camera is also used to send the captured iris image data to the processing module. The processing module performs user identity recognition based on the iris image data. The processing module is also used to control the first fill light unit and the second fill light unit to start. The first fill light unit is used to provide a fill light beam to the wide-angle camera, and the second fill light unit is used to provide a fill light beam to the iris camera.

[0008] Optionally, the iris image acquisition module includes an iris camera with adjustable imaging depth of field.

[0009] Optionally, the iris image acquisition module includes at least two fixed-focus iris cameras with different imaging depths of field.

[0010] Optionally, the at least two fixed-focus iris cameras with different imaging depths of field distances include a first iris camera and a second iris camera, and the imaging distance range of the first iris camera and the imaging distance range of the second iris camera partially overlap.

[0011] Optionally, the aperture F1 of the first iris camera satisfies 4≤F1≤10, and the aperture F2 of the second iris camera satisfies 6≤F2≤16.

[0012] Optionally, the wide-angle camera includes an imaging chip and a wide-angle lens, and the imaging chip and the wide-angle lens are arranged on the same optical axis or the optical axis of the imaging chip and the optical axis of the wide-angle lens are offset by a preset distance.

[0013] Optionally, the optical axis of the first fill light unit is parallel to the optical axis of the wide-angle camera, the perpendicular line of the optical axis of the wide-angle camera has a first preset angle that is not zero with the first direction, and the first direction is parallel to the plane where the door lock cover plate of the smart door lock is located.

[0014] Optionally, the second fill light unit includes an infrared vertical cavity surface emitting laser.

[0015] Optionally, the optical axis of the iris camera is parallel to the plane where the door lock cover plate of the smart door lock is located, or the absolute value of the acute angle between the optical axis of the iris camera and the plane where the door lock cover plate of the smart door lock is located is less than or equal to 45°, and the imaging field of view of the iris camera is tilted toward one side of the reflection unit.

[0016] Optionally, the processing module is further configured to perform user face recognition and / or palm recognition based on the image data acquired by the wide-angle camera.

[0017] Optionally, the wide-angle camera integrates a cat's eye function.

[0018] Optionally, the imaging system further includes a downward-looking camera, which is used to view objects outside the door.

[0019] Optionally, the imaging system further includes an interior camera, which is used to capture images inside the house.

[0020] According to another aspect of the present invention, a smart door lock is provided, comprising the above-mentioned imaging system.

[0021] An imaging system provided in an embodiment of the present invention is used in a smart door lock. The imaging system includes a wide-angle image acquisition module, an iris image acquisition module, a light reflection control module, and a processing module. The wide-angle image acquisition module, the iris image acquisition module, and the light reflection control module are all connected to the processing module. The wide-angle image acquisition module includes a wide-angle camera and at least one first fill light unit. The iris image acquisition module includes at least one iris camera and at least one second fill light unit. The light reflection control module includes a reflection unit and a control unit. The reflection unit is located in the optical path of the iris camera and the second fill light unit. The first fill light unit and the second fill light unit provide fill light beams to the wide-angle camera and the iris camera, respectively. First, the wide-angle camera is used to capture images within the field of view, and the captured image data is sent to the processing module. When the processing module detects that there are human eyes in the captured image through image processing, it can be determined that the smart door lock has the need for user identification, thereby controlling the iris camera to start. The processing module calculates the distance between the human eye and the smart door lock and the deflection angle of the human eye position relative to the optical axis of the wide-angle camera and / or the reflection unit based on the image data output by the wide-angle camera. The appropriate depth of field of the iris camera is selected according to the distance, and the rotation of the reflection unit is adjusted according to the deflection angle, thereby changing the field of view and depth of field of the iris camera imaging, so that the human eye can be clearly imaged on the iris camera, thereby improving the accuracy of user identity recognition.

[0022] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A structural block diagram of an imaging system provided by an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a partial structure of an imaging system provided by an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of a partial structure of another imaging system provided by an embodiment of the present invention;

[0027] Figure 4 A schematic diagram of a partial structure of another imaging system provided by an embodiment of the present invention;

[0028] Figure 5 A schematic structural diagram of an iris camera provided by an embodiment of the present invention;

[0029] Figure 6 A schematic structural diagram of another iris camera provided by an embodiment of the present invention;

[0030] Figure 7 A front view of a partial structure of an imaging system provided by an embodiment of the present invention;

[0031] Figures 8 to 10 They are respectively side views of a partial structure of an imaging system provided by an embodiment of the present invention;

[0032] Figure 11 A schematic diagram of imaging of a wide-angle camera of an imaging system provided by an embodiment of the present invention;

[0033] Figure 12 A structural block diagram of another imaging system provided by an embodiment of the present invention;

[0034] Figure 13 A schematic structural diagram of an imaging system provided by an embodiment of the present invention;

[0035] Figure 14 A structural block diagram of another imaging system provided by an embodiment of the present invention;

[0036] Figure 15 A schematic structural diagram of another imaging system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] Figure 1 This is a structural block diagram of an imaging system provided by an embodiment of the present invention. The imaging system provided by an embodiment of the present invention is used in a smart door lock, wherein the smart door lock is a smart door lock with an iris recognition function. Figure 1 The imaging system includes a wide-angle image acquisition module 11, an iris image acquisition module 12, a light reflection control module 13 and a processing module 14, wherein the wide-angle image acquisition module 11, the iris image acquisition module 12 and the light reflection control module 13 are all connected to the processing module 14; the wide-angle image acquisition module 11 includes a wide-angle camera and at least one first fill light unit, the iris image acquisition module 12 includes at least one iris camera and at least one second fill light unit, the light reflection control module 13 includes a reflection unit and a control unit, and the reflection unit is located in the optical path between the iris camera and the second fill light unit; wherein the connection between the wide-angle image acquisition module 11, the iris image acquisition module 12 and the light reflection control module 13 and the processing module 14 is not only a physical electrical connection, but also includes the exchange of data transmission protocols and control signals; the reflection unit is located in the path of light emission of the second fill light unit and light reception of the iris camera, and is used to change the field of view of the iris camera for capturing iris images so that the light reflected by the human eye falls within the field of view of the iris camera.

[0040] The basic principle of the imaging system provided by the embodiment of the present invention is as follows: the wide-angle camera is used to capture images within the field of view and send the captured image data to the processing module 14; the processing module 14 is used to control the first fill light unit to start up to provide a fill light beam for the wide-angle camera; when it is detected through image processing that there is a human eye in the captured image, the distance between the human eye and the smart door lock and the deflection angle of the human eye relative to the optical axis of the wide-angle camera and / or the reflection unit are calculated based on the image data output by the wide-angle camera; the iris camera and the second fill light unit are controlled to start up and the control unit is driven to control the reflection unit to change the deflection angle of the reflection unit, thereby changing the illumination range of the fill light beam provided by the second fill light unit and the field of view of the iris camera imaging, and adjusting the depth of field of the iris camera so that the human eye can be clearly imaged on the iris camera; the iris camera is also used to send the captured iris image data to the processing module 14; the processing module 14 performs user identity recognition based on the iris image data, thereby improving the accuracy of iris recognition.

[0041] Figure 2 A schematic diagram of a partial structure of an imaging system provided by an embodiment of the present invention is provided. Figure 3 A schematic diagram of a partial structure of another imaging system provided by an embodiment of the present invention, referring to Figure 2 and Figure 3 In one embodiment, the wide-angle image acquisition module includes a first fill light unit 111 and a wide-angle camera 112 , and the optical axis O3 of the first fill light unit 111 is parallel to the optical axis O1 of the wide-angle camera 112 .

[0042] The wide-angle camera 112 may include an imaging chip 1121, a filter 1122, and a lens 1123. Figure 2 , the imaging chip 1121 and the wide-angle lens 1123 are arranged on the same optical axis, or refer to Figure 3, the optical axis O2 of the imaging chip 1121 and the optical axis O1' of the wide-angle lens 1123 are offset by a preset distance. The wide-angle camera 112 can be an infrared single-pass camera or a visible light and infrared dual-pass camera. The first fill light unit 111 emits infrared light. Generally, the wavelength of the infrared light can be 700nm to 1000nm, and the number can be one or more (depending on the actual fill light brightness requirements). When the wide-angle camera 112 is an infrared single-pass camera, when an object approaches the door lock or the imaging system receives relevant instructions such as unlocking, the processing module controls the simultaneous activation of the first fill light unit 111 and the wide-angle camera 112; when the wide-angle camera 112 is a visible light and infrared dual-pass camera When an object approaches the door lock or the imaging system receives unlocking and other related instructions, the processing module first starts the wide-angle camera 112, and the wide-angle camera 112 sends the collected image to the processing module. The processing module determines the image collection brightness. When the image brightness is higher than the preset threshold, the first fill light unit 111 is not turned on. When the image brightness is lower than the preset threshold, the processing module controls the start of the first fill light unit 111 to fill light. The field of view of the wide-angle camera 112 needs to cover the field of view areas of faces of different heights and different collection distances, and a reasonable field of view angle is set according to different test requirements.

[0043] For example, in some embodiments, reference Figure 2 The optical axis O1 of the wide-angle camera 112 is placed perpendicular to the door lock cover (i.e., the optical axis is parallel to the Z direction). The wide-angle camera 112 is installed at a height range of 1.2m to 1.4m from the ground. The camera's field of view covers a height range of 1.1m to 1.9m, and a range of 35cm to 90cm from the face to the door. Generally, the vertical field of view of the wide-angle camera 112 is required to be greater than 110°. Figure 2 It can be seen that the face is generally located at the upper part of the field of view of the wide-angle camera 112. In some embodiments, reference Figure 3 , the optical axis of the imaging chip 1121 (the axis passing through the optical center of the wide-angle lens 1123 and parallel to the Z direction) can be offset in the -Y direction so that the field of view in the +Y direction received by the imaging chip 1121 is larger than the field of view in the -Y direction. In this way, a camera with a smaller field of view angle can be selected, which can cover the test area of ​​the human face. The same embodiment as above requires that the vertical field of view angle of the wide-angle camera 112 is greater than 95°.

[0044] In some embodiments, the wide-angle camera and the first fill light unit can be installed at a certain angle. Figure 4 A schematic diagram of a partial structure of another imaging system provided in an embodiment of the present invention, referring to Figure 4The optical axis O3 of the first fill light unit 111 is parallel to the optical axis O1 of the wide-angle camera 112. The perpendicular line of the optical axis O1 of the wide-angle camera 112 has a first preset angle α that is not zero with the first direction Y. The first direction Y is parallel to the plane where the door lock cover plate of the smart door lock is located, and preferably α is less than 45°.

[0045] like Figure 4 As shown, the installation angle between the wide-angle camera 112 and the first fill light unit 111 is α, and the angle α is the angle between the vertical line of the optical axis O1 of the wide-angle camera 112 and the Y axis. Figure 3 A camera with a smaller field of view can also be selected. The same embodiment as above requires that the vertical field of view of the wide-angle camera 112 is greater than 95°. It can be understood that in other embodiments, the optical axis O3 of the first fill light unit 111 and the optical axis O1 of the wide-angle camera 112 can also be designed to be non-parallel. The specific implementation can be designed according to actual conditions.

[0046] In some embodiments, it is possible to combine Figure 3 and Figure 4 In the solution, the imaging chip and the wide-angle lens are set to an eccentric design. The tilted installation angle of the superimposed imaging system requires a larger offset value for the imaging chip. Figure 3 Small, the optical system assembly tilt angle is also small Figure 3 Smaller, but still achievable Figure 3 and Figure 4 effect.

[0047] Existing iris cameras have a small depth of field and a short imaging distance. For example, when capturing human eye images at a distance of 10cm to 25cm from the iris camera, the face needs to be relatively close, resulting in a poor user experience. The iris camera in the imaging system provided by the embodiments of the present invention can accommodate a wider range of acquisition distances, such as 35cm to 90cm. The iris lens used has a focal length greater than 6mm. However, existing lenses with a focal length greater than 6mm generally have a short depth of field, and cannot achieve clear imaging of the entire acquisition range by focusing at a single distance to meet the requirements of iris recognition. The embodiments of the present invention provide two methods:

[0048] In a first embodiment, the iris image acquisition module optionally includes an iris camera with an adjustable imaging depth of field.

[0049] For example, Figure 5 This is a structural diagram of an iris camera provided by an embodiment of the present invention, with reference to Figure 5The iris camera includes a circuit board 1221, an imaging chip 1222, a filter 1223, a bracket 1224, a voice coil motor 1225 and an iris lens 1226. When the processing module detects a human eye from the image data output by the wide-angle camera, it calculates the collected human eye position and the camera distance value, and simultaneously starts the second fill light unit and the iris camera. The processing module adjusts the current supplied to the voice coil motor 1225 according to the human eye distance value, thereby driving the iris lens 1226 to move different distances along the optical axis, that is, changing the distance between the iris lens 1226 and the imaging chip 1222, and changing the imaging depth of field range of the iris camera. This allows images collected at different distances to be focused near the distance, and clear images can be obtained at different positions, solving the problem of the small imaging depth of field range of the telephoto lens.

[0050] In a second embodiment, the iris image acquisition module optionally includes at least two fixed-focus iris cameras with different imaging depths of field.

[0051] By setting at least two fixed-focus iris cameras with different imaging depths of field, each camera is responsible for collecting iris images in different distance ranges. Optionally, the at least two fixed-focus iris cameras with different imaging depths of field distances include a first iris camera and a second iris camera, and the imaging distance range of the first iris camera and the imaging distance range of the second iris camera partially overlap.

[0052] For example, Figure 6 This is a structural diagram of another iris camera provided by an embodiment of the present invention, referring to Figure 6 The iris camera includes a circuit board 1221, an imaging chip 1222, a filter 1223, a base (bracket) 1224 and an iris lens 1226. The imaging system provided by the embodiment of the present invention may include at least two Figure 6The fixed-focus iris camera shown in the figure is responsible for collecting iris images in different distance ranges. Two iris cameras are preferred, such as the first iris camera is responsible for collecting iris images at a closer distance, such as 35cm to 60cm, and the second iris camera is responsible for collecting iris images at a longer distance, such as 55cm to 90cm. The focal length of the first iris camera is smaller than that of the second iris camera, and the field of view of the first iris camera is larger than that of the second iris camera. The preferred focal length range of the first iris camera is 7mm to 24mm, and the focal length range of the second iris camera is 9mm to 38mm. The horizontal field of view of the first iris camera is preferably 15° to 30°, and the horizontal field of view of the second iris camera is preferably 10° to 20°. However, due to the small depth of field range of the traditional telephoto lens, it still cannot meet the two-stage distance measurement requirements. For example, for an iris lens with a focal length of 7mm, a common iris lens The aperture is F=2, and it is matched with a chip with a single pixel size of 1.75μm. The theoretical depth of field range when focusing at 45cm is: 42cm~48cm. The embodiment of the present invention improves the depth of field range of camera imaging by reducing the aperture of the iris camera. For example, when the lens aperture is reduced to F=8, the theoretical depth of field range when focusing at 45cm can be increased to: 36cm~60cm, which greatly increases the distance range of clear imaging of a single iris camera. For existing lenses, changing the aperture size only requires reducing the aperture size of the aperture blades. The purpose of reducing the aperture can be simply achieved by reducing the aperture size of the soma leaf. There is no need to change the optical design of the original lens. The existing iris lens can be directly used, which is very convenient to implement. Preferably, the aperture F1 range for the first iris camera is 4≤F1≤10, and the aperture F2 range for the second iris camera is 6≤F2≤16.

[0053] The second method increases the depth of field range of the iris lens, so that a larger depth of field imaging distance can be covered by fewer fixed-focal-length iris cameras. Compared with automatic focus, the speed of collecting iris images is faster and the algorithm is simpler. In addition, for the solution of using multiple iris cameras, the depth of field ranges of different cameras need to reserve overlapping areas; for example, when there are two iris cameras with fixed focal lengths, the distance ranges for clear imaging of the two cameras need to have a partial overlapping distance to avoid the problem of the two iris cameras switching back and forth when the human eye is at the middle critical distance position. The preferred overlapping measurement area is 5cm; specifically, the processing module starts the iris camera responsible for the distance range according to the human eye distance value. If the distance range is in the overlapping area, you can choose to start the second iris camera first when setting it up. For example, when the distance between the human eye and the iris camera moves from greater than 55cm to less than 55cm, it switches to the first iris camera. Subsequently, when the distance between the human eye and the iris camera needs to move from less than 55cm to 60cm, it switches to the second iris camera, so that the switching image can have a smooth transition distance. Similarly, you can also choose to start the first iris camera first when setting it up. The distance switching method is similar to the above.

[0054] The advantage of the above embodiment is that if the effective acquisition distances of multiple fixed-focus iris cameras are aligned, with no overlap, when the user is at the critical point of the effective acquisition distance, the detected distance may fluctuate due to potential errors in the distance detection algorithm, or the user may move within a small range before or after the acquisition distance. This can cause the iris cameras to frequently switch, affecting device stability. The presence of some overlap in the effective acquisition distances of multiple fixed-focus iris cameras effectively avoids boundary oscillation at the critical distance, preventing erratic and frequent switching of the iris cameras and ensuring smooth switching of the iris cameras.

[0055] For example, Figure 7 A front view of a partial structure of an imaging system provided by an embodiment of the present invention is provided for reference Figure 7The iris image acquisition module includes a second fill light unit 121 and an iris camera 122. During iris recognition, the second fill light unit 121 and the iris camera 122 are simultaneously activated. The second fill light unit 121 provides a fill light beam, thereby improving the image quality of the iris camera 122 and enhancing iris recognition accuracy. The light reflection control module includes a reflective unit 131, a rotating shaft 132, and a control unit 133. The rotating shaft 132 is fixed to the reflective unit 131. The control unit 133 is mechanically connected to the rotating shaft 132. The control unit 133 can drive the rotating shaft 132 to rotate, thereby driving the reflective unit 131 to rotate at different angles. The light emitted by the second fill light unit 121 is reflected by the reflective unit 131, deflected at a certain angle, and projected onto the detected area. The light reflected from the detected area is reflected by the reflective unit 131, deflected at a certain angle, and then enters the iris camera 122 for imaging, thereby capturing an iris image of the human eye.

[0056] When the imaging system receives an instruction to capture an image of a human eye, or when a human eye is detected in the image output by the wide-angle image capture module, the processing module will simultaneously activate the iris camera 122 and the second fill light unit 121. In some cases, it will first determine whether the received iris image meets the requirements. If it does not meet the requirements, the facial image is captured by the wide-angle camera, and the deflection angle of the human eye relative to the optical axis of the wide-angle camera and / or the reflection unit 131 is calculated. Then, the control unit 133 drives the rotating shaft 132 to rotate, thereby driving the reflection unit 131 to rotate, so that the light reflected by the measured human eye falls on the effective imaging area of ​​the iris camera 122.

[0057] Figures 8 to 10 are side views of a partial structure of an imaging system provided by an embodiment of the present invention, with reference to Figure 8 , the angle between the reflecting surface of the reflecting unit 131 and the +Z axis is β, and the field angle range of the iris camera 122 is θ. When the optical axis of the iris camera 122 is installed parallel to the Y axis, the central light beam is deflected by (180°-2β) after passing through the reflecting unit 131 and is imaged at the center of the iris camera 122. When the reflecting unit 131 is fixed at a certain position, the reflecting unit 131 does not change the field angle of the iris on the imaging optical path of the iris camera 122, that is, the field angle of the iris camera 122 is still θ after passing through the reflecting unit 131. When the reflecting unit 1 When the reflective unit 131 is rotated clockwise by an angle of γ at this position, the angle of the incident central light beam is rotated clockwise by an angle of γ2=2γ, and the receiving field of view of the iris camera 122 is rotated clockwise by 2γ on the basis of the initial position. Similarly, when the reflective unit 131 is rotated counterclockwise by an angle of γ at this position, the angle of the incident central light beam is rotated counterclockwise by an angle of γ1=2γ, and the receiving field of view of the iris camera 122 is rotated counterclockwise by 2γ on the basis of the initial position. By rotating the reflective unit 131, the receiving field of view of the iris camera 122 can be greatly increased.

[0058] Figure 8 The receiving field of view of the iris camera 122 is symmetrical about the Z axis. In fact, the human eye mainly appears in the upper half of the field of view. In some embodiments, optionally, refer to Figure 8 , the optical axis of the iris camera 122 is parallel to the plane (Y direction) where the door lock cover of the smart door lock is located, or reference Figure 9 The absolute value of the acute angle between the optical axis of the iris camera 122 and the plane where the door cover of the smart door lock is located is less than or equal to 45°, and the imaging field of the iris camera 122 is tilted toward the side of the reflective unit 131. Figure 2 or Figure 3 By offsetting the optical center of the chip from the optical axis of the lens, the receiving field of view of the iris camera 122 after deflection by the reflection unit 131 is: the field of view angle in the +Z direction is greater than the field of view angle in the -Z direction, such as Figure 9 The angle between the optical axis of the iris camera 122 and the Y axis is α2 ( Figure 9 The angle between the vertical line of the optical axis of the iris camera 122 and the Z axis is shown in FIG. Figure 8 To achieve the same size of +Z direction field of view, Figure 9 The angle that the middle reflective unit 131 needs to rotate counterclockwise is larger. Figure 8 Small α2 can, on the one hand, reduce the rotation range of the reflecting unit 131 and increase the rotation speed; on the other hand, it can greatly reduce the size of the reflecting unit 131 (reduce the aperture of the light beam projected by the iris camera 122 on the reflecting unit 131), thereby reducing the cost and volume of the imaging system.

[0059] In some embodiments, reference may also be made to Figure 10 The iris camera 122 and the reflective unit 131 are placed in a manner such that the optical axis of the iris camera 122 is along the -Y direction, similar to Figure 8 Set the optical axis of the iris camera 122 and the plane where the door lock cover of the smart door lock is located, or similar Figure 9 The absolute value of the acute angle between the optical axis of the iris camera 122 and the plane where the door lock cover of the smart door lock is located is less than or equal to 45°, and the imaging field of the iris camera 122 is tilted toward the side of the reflective unit 131, and the angle between the reflective unit 131 and the -Z axis is β. This method can also reduce the counterclockwise rotation angle of the reflective unit 131. Figure 8 Likewise, the rotation range of the reflecting unit 131 and the size of the reflecting unit 131 can be reduced.

[0060] The above-mentioned reflective unit 131 rotates the viewing range of the iris camera 122 while also rotating the viewing range of the light beam emitted by the second fill light unit 121. The reason is the same as above. Figures 8 to 10The rotation diagram of the second fill light unit 121 is not shown in FIG, and will not be described again here.

[0061] Other assembly methods not mentioned above, as long as they use the reflection unit 131 to simultaneously deflect the field of view of the iris camera 122 and the second fill light unit 121 to increase the imaging field of view of the actual iris image acquisition module, are within the protection scope of the embodiments of the present invention.

[0062] Optionally, the second fill light unit includes an infrared light emitting diode or an infrared vertical cavity surface emitting laser.

[0063] Among them, existing iris cameras usually use infrared light-emitting diodes (LEDs) as fill light units. In the embodiments of the present invention, infrared vertical cavity surface emitting lasers (VCSELs) are preferably used as fill light units. The advantages of VCSEL as a fill light unit over LEDs are as follows:

[0064] 1) Simple structure. The initial half-intensity angle of an LED light-emitting chip is generally 120°. A lens needs to be added to converge the light emitted by the light chip to a smaller divergence angle. For example, the divergence angle corresponding to half-intensity is 30°. The divergence angle of the VCSEL chip itself is relatively small, generally between 10° and 35°. That is, there is no need to add an optical lens, and the corresponding divergence angle can be well matched with the field of view of the iris camera.

[0065] 2) The iris imaging system has strong resistance to ambient light interference. There are two reasons for this. First, VCSEL has good monochromatic performance. The spectral half-bandwidth of a general LED is greater than 30nm, while the spectral half-bandwidth of a VCSEL is less than 2nm. In this way, the filter in the iris camera can be designed with a smaller bandwidth, allowing most of the light from the fill light to pass through the filter. The narrower the bandwidth, the weaker the intensity of the ambient light passing through the filter, and the smaller the impact on the image formation of the iris camera. Second, the wavelength temperature drift of VCSEL is small. The temperature drift of a general LED is 0.3nm / ℃, while the temperature drift of a VCSEL is generally 0.07nm / ℃. m / ℃. For example, if the temperature changes by 50℃, the wavelength of the LED changes by 15nm, while the wavelength of the VCSEL changes by only 3.5nm, which is much smaller than the temperature drift of the LED wavelength. The impact of temperature change on wavelength also needs to be considered when designing the passband width of the iris camera filter. Generally, the bandwidth of the filter needs to be designed to be larger than the bandwidth of the light source + temperature drift. In this way, when using a VCSEL light source as a fill light unit, the filter bandwidth of the iris camera can be designed to be narrower than when using an LED as a fill light unit. Less ambient light passes through the filter to reach the imaging chip for imaging, which has less impact on the image formation of the iris camera.

[0066] 3) Low energy consumption. VCSEL has a high photoelectric conversion efficiency. Generally, the photoelectric conversion efficiency of VCSEL is greater than 33%, while the photoelectric conversion efficiency of LED is lower. Under the same current, the conversion efficiency is only about 26% to 28%, which causes the LED to generate more heat when working.

[0067] Figure 11 An imaging diagram of a wide-angle camera of an imaging system provided by an embodiment of the present invention, with reference to Figure 11 , the distance between the wide-angle camera 112 and the person in the Z direction is L1, the corresponding position of the square box in the figure is the viewfinder frame of the wide-angle camera 112, the distance between the center height of the eye line and the installation center height of the wide-angle camera 112 is L2, the center distance of the eye is D, and the center distance of the eye is about 65mm according to statistics. The actual distance between the centers of the eyes in the image can be obtained according to the pixel coordinate difference of the line connecting the centers of the two eyes and the single pixel size p of the chip. For example, if the centers of the two eyes are in the image pixel coordinate system (the image pixel coordinate system uses the number of rows and columns of the chip as the x and y axes, and the unit is the number of pixels), the difference in the long side direction of the pixels is Δx, and the difference in the short side direction of the pixels is Δy, then the actual distance between the center points of the two eyes in the image is In the same way, we can calculate that the imaging distance of the L2 segment on the chip is l2, and D / L2=d / l2, where D, l2, and d are all known, and we can calculate L2=D×l2 / d. According to the imaging theory of the camera, we know that: D / d=L1 / f, (where f is the focal length of the lens), where D, d, and f are known, and we can calculate L1=D×f / d. Figure 11 The offset angle Φ of the center of the eye line relative to the optical axis of the wide-angle camera 112 is shown as arctan(L2 / L1). Based on L1 and L2 calculated above, Φ can be calculated. The processing module drives the shaft to rotate by an angle Φ / 2 through the control unit, thereby driving the reflection unit to rotate by Φ / 2. This causes the light reflected from the measured eye to rotate by an angle Φ and fall into the effective imaging area of ​​the iris camera.

[0068] In the above embodiment, the center height of the image framing of the iris camera in the initial state is the same as the center height of the framing of the wide-angle camera. In some embodiments, if the center height of the image framing of the iris camera in the initial state has an angle Ψ with the optical axis of the wide-angle camera, the processing module drives the rotating shaft to rotate at an angle of Φ / 2±Ψ / 2 through the control unit.

[0069] In some embodiments, wide-angle cameras have significant distortion. When calculating L1, it is necessary to consider the effect of this distortion on the Φ angle. In some embodiments, the wide-angle camera's optical axis is at a certain angle to the Z axis, and the effect of this initial angle on the calculated Φ angle must also be considered. The principles for calculating Φ angle are the same as above and are all within the scope of the present invention.

[0070] The embodiments of the present invention are suitable for acquiring eye images of users of different heights. Users do not need to bend over or stand on tiptoe. As long as the distance between the user and the device is within the effective acquisition range, the device can automatically adjust the field of view of the iris camera to capture images, so that the field of view of the iris camera is aligned with the user's eyes, and iris recognition is performed by acquiring images containing human eye information.

[0071] The iris camera and the second fill light unit are fixed, and the imaging field of view is changed by rotating the reflective unit. Compared with traditional products that rotate the iris camera, this solution has the following advantages:

[0072] 1) Fast adjustment speed. Traditionally, the angle of the camera is adjusted by rotating the camera module. For example, when the deflection angle between the optical axis of the camera module and the target position is Φ, the camera module needs to be driven to rotate by an angle of Φ. However, the embodiment of the present invention uses a reflection unit to deflect the light beam. The camera is fixed in position. By rotating the reflection unit by an angle of Φ / 2, the imaging field angle of the camera can be rotated by Φ. On the one hand, a driving unit with a smaller range can be selected. On the other hand, due to the smaller rotation angle, the angle adjustment speed is also faster.

[0073] 2) High reliability. The iris camera is an active device. The traditional method of rotating the camera often causes the circuit wiring to be pulled due to the rotation, which affects the electrical performance of the camera. The embodiment of the present invention replaces the rotating camera with a rotating reflection unit, which is more friendly to the circuit and has high product reliability.

[0074] 3) Reduce fill light power consumption and improve fill light uniformity. The field of view of the second fill light unit can also change with the rotation of the reflective unit. The fill light field of view of the second fill light unit can be used to cover the imaging field of view of the iris camera without covering the entire imaging range of the required face. In this way, a fill light unit with a smaller field of view angle can be selected, which has low power consumption and good fill light uniformity.

[0075] 4) The structure is design-friendly. The camera and the reflective unit can be installed at different positions and angles with high flexibility, which is very friendly to the structure design.

[0076] In other embodiments, optionally, the processing module is also used to perform user face recognition and / or palm recognition based on image data acquired by the wide-angle camera, and confirm whether to unlock by evaluating whether the face and / or palm in the image matches the face and / or palm feature information stored in the system.

[0077] In addition to iris recognition, the imaging system also integrates face and / or palm recognition. On the one hand, the multimodal recognition method can meet the unlocking habits of different users. On the other hand, it can also perform complex recognition when unlocking. Multiple recognition results must be successful to unlock, which improves recognition accuracy and door lock security.

[0078] In another embodiment, optionally, the wide-angle camera integrates a cat's eye function.

[0079] By combining the wide-angle camera with the cat's eye function, real-time images outside the door can be viewed remotely via mobile phone. After binding the mobile phone APP, you can view the dynamics outside the door through your mobile phone anytime and anywhere even if you are not at home, which enriches the functions of the imaging system. That is, a wide-angle camera can take into account the functions of cat's eye, face and palm recognition, and detection of human eye position. The specific implementation can be designed according to actual conditions.

[0080] Figure 12 A structural block diagram of another imaging system provided by an embodiment of the present invention is shown. Figure 13 A schematic diagram of the structure of an imaging system provided by an embodiment of the present invention, referring to Figure 12 The imaging system further includes a down-camera image acquisition module 15, which is used to monitor express parcels or other items placed in front of the door to prevent them from being lost or taken by mistake. Figure 13 The downward image acquisition module also includes a downward-looking camera 152, which is used to view objects outside the door. It can also include a third fill light unit 151. The third fill light unit 151 can be an infrared fill light, which is turned on when the ambient brightness is lower than a certain threshold. The downward-looking camera 152 can include a circuit board, an imaging chip, a filter, a base / bracket, and a lens. The filter can be a dual-pass filter that can pass visible light and light corresponding to the wavelength of the third fill light unit 151. In some cases, the downward-looking camera 152 also includes an automatic filter switching device (IRCUIT). The IRCUIT has two filters with different passbands: one is an infrared cutoff filter that passes visible light, and the other is an infrared bandpass filter that can pass light beams with the same wavelength as the third fill light unit 151. When the ambient brightness is higher than a certain threshold, the IRCUIT switches the infrared cutoff filter to the camera's optical path to cut off light beams outside the visible light band. When the ambient brightness is lower than a certain threshold, the IRCUIT switches the infrared bandpass filter to the camera's optical path to cut off light beams outside the band of the third fill light unit 151.

[0081] The downward image acquisition module 15 of the present invention is installed below the lock body of the smart door lock. The bottom of the lock body can be perpendicular to the door lock (that is, the panel below the lock body is horizontal and parallel to the ground), or it can be at a certain angle to the ground, and the angle to the ground is preferably between 0 and 45 degrees). The advantages of the installation position are: 1) It is highly concealed and not easy to be detected, and can accurately cover the express delivery area; 2) The use of a lens with a smaller field of view angle can effectively match the imaging field of view area of ​​the ground and low areas; the downward image acquisition module 15 is electrically connected to the processing module 14 for communication, and is located on different main boards of the processing module 14, and is connected in the middle by a flexible cable. Compared with the traditional downward-looking camera, which must be installed independently of the recognition module in the bottom area near the door, the imaging system provided by the present invention does not require additional installation equipment, and has integrated functions, which further increases the use function of the imaging system.

[0082] Figure 14 A structural block diagram of another imaging system provided by an embodiment of the present invention is shown. Figure 15 A schematic diagram of another imaging system according to an embodiment of the present invention is provided. Figure 14 The imaging system also includes a rear-camera image acquisition module 16, which is used to capture images inside the house. It can be used to monitor the situation at home, ensure the safety of family members, and record activities at home in real time to help users understand the dynamics of the home at any time. Generally, the rear-camera image acquisition module 16 also includes a fourth fill light unit and an interior camera, which is installed in the lock body cover on the side of the smart door lock close to the house. It is also electrically connected to the processing module 14 through a flexible board line. The principle is the same as above and will not be repeated here. This further enriches the use function of the imaging system.

[0083] An embodiment of the present invention further provides a smart door lock, comprising any one of the imaging systems provided in the above embodiments.

[0084] Since the smart door lock provided by the embodiment of the present invention includes any one of the imaging systems provided by the above embodiments, it has the same or corresponding technical effects as the imaging system and will not be described in detail here.

[0085] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. An imaging system, characterized in that: Used in smart door locks, the imaging system includes a wide-angle image acquisition module, an iris image acquisition module, a light reflection control module and a processing module, and the wide-angle image acquisition module, the iris image acquisition module and the light reflection control module are all connected to the processing module; The wide-angle image acquisition module includes a wide-angle camera and at least one first fill light unit, the iris image acquisition module includes at least one iris camera and at least one second fill light unit, and the light reflection control module includes a reflection unit and a control unit, wherein the reflection unit is located in the optical path between the iris camera and the second fill light unit; The wide-angle camera is used to capture images within the field of view and send the captured image data to the processing module. When the processing module detects that there is a human eye in the captured image through image processing, it calculates the distance between the human eye and the smart door lock and the deflection angle of the human eye relative to the optical axis of the wide-angle camera and / or the reflection unit based on the image data output by the wide-angle camera, controls the iris camera to start and drives the control unit to control the reflection unit to change the deflection angle of the reflection unit, thereby changing the field of view of the iris camera imaging and adjusting the depth of field of the iris camera so that the human eye can be clearly imaged on the iris camera. The iris camera is also used to send the captured iris image data to the processing module. The processing module performs user identity recognition based on the iris image data. The processing module is also used to control the first fill light unit and the second fill light unit to start. The first fill light unit is used to provide a fill light beam to the wide-angle camera, and the second fill light unit is used to provide a fill light beam to the iris camera.

2. The imaging system according to claim 1, wherein: The iris image acquisition module includes an iris camera with adjustable imaging depth of field.

3. The imaging system according to claim 1, wherein: The iris image acquisition module includes at least two fixed-focus iris cameras with different imaging depths of field.

4. The imaging system according to claim 3, wherein: The at least two fixed-focus iris cameras with different imaging depths of field distances include a first iris camera and a second iris camera, and the imaging distance range of the first iris camera and the imaging distance range of the second iris camera partially overlap.

5. The imaging system according to claim 4, wherein: The aperture F1 of the first iris camera satisfies 4≤F1≤10, and the aperture F2 of the second iris camera satisfies 6≤F2≤16.

6. The imaging system according to claim 1, wherein: The wide-angle camera includes an imaging chip and a wide-angle lens. The imaging chip and the wide-angle lens are arranged on the same optical axis, or the optical axis of the imaging chip and the optical axis of the wide-angle lens are offset by a preset distance.

7. The imaging system according to claim 1, wherein: The optical axis of the first fill light unit is parallel to the optical axis of the wide-angle camera, the perpendicular line of the optical axis of the wide-angle camera has a first preset angle that is not zero with the first direction, and the first direction is parallel to the plane where the door lock cover plate of the smart door lock is located.

8. The imaging system according to claim 1, wherein: The second fill light unit is an infrared vertical cavity surface emitting laser.

9. The imaging system according to claim 1, wherein: The optical axis of the iris camera is parallel to the plane where the door lock cover plate of the smart door lock is located, or the absolute value of the acute angle between the optical axis of the iris camera and the plane where the door lock cover plate of the smart door lock is located is less than or equal to 45°, and the imaging field of view of the iris camera is tilted toward one side of the reflective unit.

10. The imaging system according to claim 1, wherein: The processing module is further configured to perform user face recognition and / or palm recognition based on the image data acquired by the wide-angle camera.

11. The imaging system according to claim 1, wherein: The wide-angle camera integrates a cat's eye function.

12. The imaging system according to claim 1, wherein: The imaging system further comprises a downward-looking camera, which is used to view objects outside the door.

13. The imaging system according to claim 1, wherein: The imaging system further comprises an interior camera, which is used to capture images inside the house.

14. A smart door lock, characterized in that: The imaging system comprises any one of claims 1 to 13.

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