Pyroelectric lens system and detection method for target detection object

Abstract

An embodiment of the present application provides a pyroelectric lens system and a detection method for a target detection object. The pyroelectric lens system includes a lens, at least two PIRs, and a processing module. Among them, the cross-sectional baseline of the lens is arc-shaped, at least two PIRs are parallel to each other and are deployed on the same plane on the concave side of the lens. Each PIR includes at least two sensing elements, the at least two sensing elements are arranged in parallel, and the connection line of the at least two sensing elements is parallel to the connection line of the at least two PIRs. The processing module is used to adjust the distance between adjacent PIRs to detect the target detection object, and the distance between adjacent PIRs is proportional to the speed of the target detection object. The system achieves the effects of improving the detection accuracy and flexibility, and reducing the cost and the overall volume of the system.

Description

Technical Field

[0001] This application relates to the technical field of lenses, and particularly to a pyroelectric lens system and a method for detecting a target detection object. Background Art

[0002] In order to improve the battery life of a surveillance camera, it is usually required that the surveillance camera be awakened under certain specific conditions and achieve target capture or video recording. A relatively common method in the industry is to use a Passive Infrared Detector (PIR) solution to detect a target detection object, so as to trigger the wake-up and capture function of the surveillance camera when the target detection object is detected.

[0003] In the existing PIR solution, the structure of a single lens + PIR is difficult to meet the detection requirements for target detection objects with different speeds. Currently, mainly according to the actual scenario requirements, the switching of different PIR + lens combinations is achieved through single device multi-windows or single window multi-devices.

[0004] However, the existing technology has low detection accuracy and flexibility, a large volume, and a high cost. Summary of the Invention

[0005] The embodiments of this application provide a pyroelectric lens system and a method for detecting a target detection object, so as to achieve the effects of improving detection accuracy and flexibility, reducing the volume and cost of the pyroelectric lens system.

[0006] In a first aspect, the embodiments of this application provide a pyroelectric lens system, including:

[0007] A lens, at least two PIRs, and a processing module;

[0008] The baseline of the cross-section of the lens is arc-shaped, the at least two PIRs are parallel to each other, and are deployed on the same plane on the concave side of the lens;

[0009] Each PIR includes at least two sensing elements, the at least two sensing elements are arranged in parallel, and the connection line of the at least two sensing elements is parallel to the connection line of the at least two PIRs;

[0010] The processing module is used to adjust the distance between adjacent PIRs to detect a target detection object, and the distance between adjacent PIRs is proportional to the speed of the target detection object.

[0011] In a second aspect, the embodiments of this application provide a method for detecting a target detection object, which is applied to the processing module in the pyroelectric lens system described in the first aspect. The method includes:

[0012] Determine the target distance according to the speed of the target detection object and a preset mapping relationship, where the speed of the target detection object is obtained in response to a user's adjustment operation or collected by a speed sensor, the preset mapping relationship includes the corresponding relationship between speed and distance, and the target distance is proportional to the speed of the target detection object;

[0013] Adjust the distance between adjacent passive infrared detectors (PIRs) in the pyroelectric lens system according to the target distance;

[0014] Detect the target detection object through the pyroelectric lens system.

[0015] The pyroelectric lens system and the method for detecting a target detection object provided by the embodiments of the present application. The pyroelectric lens system includes a lens, at least two PIRs, and a processing module. Among them, the cross-sectional baseline of the lens is arc-shaped, at least two PIRs are parallel to each other and are deployed on the same plane on the concave side of the lens. Each PIR includes at least two sensing elements, the at least two sensing elements are arranged in parallel, and the connection line of the at least two sensing elements is parallel to the connection line of the at least two PIRs. The processing module is used to adjust the distance between adjacent PIRs to detect a target detection object, and the distance between adjacent PIRs is proportional to the speed of the target detection object. In this technical solution, the detection requirements for detection objects with different speeds can be met by adjusting the distance between adjacent PIRs, improving the detection accuracy and flexibility. Moreover, this system can be realized only with one lens + at least two PIRs, with low cost. The at least two PIRs are all on the concave side of the lens, reducing the overall volume of the system. Description of the Drawings

[0016] The drawings here are incorporated into the specification and form a part of this specification, showing the embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0017] Figure 1 It is a schematic diagram of a scenario for using the PIR scheme to implement the trigger wake-up and capture functions of a camera;

[0018] Figure 2 It is a schematic diagram of the lens corresponding to a high-speed detection object and a low-speed detection object respectively;

[0019] Figure 3 It is a schematic structure of the pyroelectric lens system provided by the present application Figure 1 ;

[0020] Figure 4 It is a schematic diagram of the lens viewing area provided by the embodiments of the present application;

[0021] Figure 5 It is a schematic diagram of the single-layer viewing area core position provided by the embodiments of the present application;

[0022] Figure 6 Schematic diagram of the propagation principle of infrared rays provided by the embodiments of the present application;

[0023] Figure 7 Schematic diagram of the bright area distribution under the set highest speed scenario provided by the embodiments of the present application Figure 1 ;

[0024] Figure 8 Schematic diagram of the included angle between adjacent viewing areas provided by the embodiments of the present application;

[0025] Figure 9 Schematic diagram of the relationship between the PIR responsivity and frequency provided by the embodiments of the present application;

[0026] Figure 10 Schematic diagram of the bright area distribution under the set lowest speed scenario provided by the embodiments of the present application;

[0027] Figure 11 Schematic diagram of the structure of 2 PIR + lenses in the prior art;

[0028] Figure 12 Schematic diagram of the edge incident angle provided by the embodiments of the present application;

[0029] Figure 13 Schematic diagram of the position of the light - impermeable baffle provided by the embodiments of the present application;

[0030] Figure 14 Schematic diagram of the structure of the pyroelectric lens system provided by the embodiments of the present application Figure 2 ;

[0031] Figure 15 Schematic diagram of the structure of PIR + filter provided by the embodiments of the present application;

[0032] Figure 16 Schematic diagram of the space coordinates of the pyroelectric lens system provided by the embodiments of the present application;

[0033] Figure 17 Schematic diagram of the inner wall of the lens provided by the embodiments of the present application;

[0034] Figure 18 Three - dimensional schematic diagram of the pyroelectric lens system provided by the embodiments of the present application;

[0035] Figure 19 Schematic diagram of the flow of the detection method of the standard detection object provided by the embodiments of the present application;

[0036] Figure 20 Schematic diagram of the electrical signal under the set highest speed scenario provided by the embodiments of the present application;

[0037] Figure 21Schematic diagram of bright area distribution in the set maximum speed scenario provided by the embodiments of the present application Figure 2 ;

[0038] Figure 22 Schematic diagram of electrical signal in the set minimum speed scenario provided by the embodiments of the present application;

[0039] Figure 23 Electrical signal generated for low-speed detection objects in the maximum speed scenario provided by the embodiments of the present application;

[0040] Figure 24 Electrical signal generated for low-speed detection objects in the minimum speed scenario provided by the embodiments of the present application.

[0041] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0042] Here, exemplary embodiments will be described in detail, and examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0043] First, the terms involved in the present application are explained:

[0044] PIR: Detects infrared radiation emitted by the human body or other objects based on the pyroelectric effect.

[0045] Induction element: A pyroelectric sensor. When infrared radiation emitted by the human body or other objects with a temperature higher than the environment irradiates the pyroelectric material of the induction element, the pyroelectric material absorbs the infrared energy, the temperature rises, and charges will be generated on the surface, causing the induction element to form an electrical signal output, thereby realizing target detection.

[0046] Lens: Used to collect and focus infrared radiation in a larger range of space onto the induction element inside the PIR, achieving the functions of focusing and collecting and converging the radiant energy of the heat source.

[0047] Viewing area: The spatial area where the PIR can sense the infrared radiation emitted by the human body or other heat sources, which is jointly determined by the installation positions and angles of both the lens and the PIR. The lens focuses the infrared radiation from different directions onto the sensing element. Each local lens is connected to the PIR to form a specific viewing direction, and the sensing element matches to achieve the viewing area range in this viewing direction. The combined viewing area ranges of multiple viewing directions constitute the entire viewing area range of the PIR.

[0048] Bright area: The area within the viewing area of the PIR where the PIR can effectively sense and detect the changes in the infrared radiation of the human body or other heat sources. In this area, when a target object moves, the detector can relatively sensitively receive the changes in infrared radiation.

[0049] Dark area: The area within the viewing area of the PIR where the PIR is not sensitive to the changes in the infrared radiation of the human body or other heat sources or cannot effectively detect them. In the dark area, even if a target object moves, the PIR cannot accurately receive sufficient changes in infrared radiation, thus not triggering the normal response mechanism.

[0050] Frequency: The density of the intervals between the bright and dark areas.

[0051] Next, the background related to this application will be explained:

[0052] Existing surveillance cameras are generally powered by battery + solar energy due to the problem of difficult environmental wiring. To improve the battery life of the surveillance cameras, it is usually required that the surveillance cameras be awakened under certain specific conditions to achieve target capture or recording. In some scenarios, such as in the fields of identifying intrusion prevention or wildlife detection, the industry generally uses the PIR solution to detect the target detection object to trigger the wake-up and capture functions of the surveillance camera when the target detection object is detected.

[0053] Figure 1 Schematic diagram of the scenario for using the PIR solution to achieve the trigger wake-up and capture functions of the camera. As Figure 1 shown in part (a) of, this scenario includes a lens and a PIR. The PIR includes two sensing elements, namely sensing element 1 and sensing element 2. The arrow direction is the forward direction of the person. Sensing element 1 and the lens form bright area 1, and sensing element 2 and the lens form bright area 2.

[0054] Through Figure 1Part (b) can be more intuitively seen that when the person moves along the arrow direction, they will pass through two bright areas respectively. When the person is in bright area 1, the infrared radiation of the person will irradiate on sensor element 1, causing sensor element 1 to form an electrical signal output; similarly, when the person is in bright area 2, the infrared radiation of the person will irradiate on sensor element 2, causing sensor element 2 to form an electrical signal output; when the person is between the two bright areas, no electrical signal is generated.

[0055] It should be understood that the electrical signal in this scenario can be represented with reference to Figure 1 the curve in part (c).

[0056] Furthermore, based on the electrical signal generated by the PIR, determine whether it meets the electrical signal characteristics of the target detection object. When it is satisfied, control the monitoring camera to turn on and take pictures.

[0057] In practical applications, the lens will be divided into multiple partitions to form multiple local lenses. The partitioning of the lens needs to be designed according to the motion characteristics of the target detection object. For example: when the motion speed of the target detection object is high speed, the lens needs to have wider partitions so as to quickly capture the infrared radiation emitted by the high-speed moving target detection object; when the motion speed of the target detection object is low speed, narrower partitions need to be formed to improve the collection efficiency of the infrared radiation of the target detection object.

[0058] Figure 2 Schematic diagrams of lenses corresponding to high-speed detection objects and low-speed detection objects respectively. As Figure 2 shown, the rectangle is the partition of the lens, and the circle is the core position of each local lens. It can be clearly seen that the width of the lens partition designed for the low-speed detection object is narrower than that designed for the high-speed detection object. Under the same lens size, the number of lens partitions designed for the low-speed detection object is greater than that designed for the high-speed detection object. When the number of partitions is large, the area of a single partition is small, and the long-distance detection ability is weak.

[0059] According to the above characteristics, for target detection objects with different speeds, the structure of a single lens + PIR has the problem of low detection accuracy. Specifically, in the scenario of lens + PIR designed for high-speed detection objects, if there are low-speed detection objects, at this time the blind area is large, the detection area is small, and there is a problem of easy missed detection; in the scenario of lens + PIR designed for low-speed detection objects, if there are high-speed detection objects, at this time the number of partitions is large, the frequency of cutting the bright area is too high, the response degree and the electrical signal generated by the high-speed detection object are low.

[0060] To solve the above problems, the prior art mostly realizes them through a single device with multiple windows or a single window with multiple devices. Specifically, a single device with multiple windows means deploying two sets of PIR + lenses on one device (such as a surveillance camera), with one set for detecting high-speed moving objects and the other for detecting low-speed moving objects. In actual applications, the two sets of PIR + lenses are switched according to the actual scenario requirements. A single window with multiple devices means deploying one set of PIR + lens structures on two devices respectively, so that one device can detect high-speed moving objects and the other device can detect low-speed moving objects. Similarly, in actual applications, the two devices are switched according to the actual scenario requirements.

[0061] However, in actual applications, the prior art has the following technical problems:

[0062] 1. There are only two fixed states (high-speed state and low-speed state) for users to switch, and the detection accuracy and flexibility are relatively low.

[0063] 2. Whether it is a single device with multiple windows or a single window with multiple devices, the system volume for realizing detection will be very large and the cost will also be very high.

[0064] In summary, the prior art has relatively low detection accuracy and flexibility, a large volume, and a high cost.

[0065] Based on the above technical problems, the technical concept of this application is as follows: For low-speed moving objects, when the dark area is large, it is not easy to detect them. Therefore, compared with high-speed moving objects, low-speed moving objects require more bright areas. Considering that the bright area within the viewing area of the PIR is jointly determined by the installation positions and angles of both the lens and the PIR, a PIR + lens structure can be designed. This structure includes at least two PIRs. By changing the distance between adjacent PIRs among the at least two PIRs, the position of the bright area formed by each PIR can be changed, and thus the bright area range within the viewing area of the PIR can be changed. In this way, it is possible to accurately detect target moving objects with different speeds through a PIR + lens structure, with a smaller overall system volume, a lower cost, and high detection accuracy and flexibility.

[0066] The following uses specific embodiments to elaborate in detail on the technical solution of this application and how the technical solution of this application solves the above technical problems. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of this application will be described below in conjunction with the accompanying drawings.

[0067] Figure 3 Structural schematic of the pyroelectric lens system provided by this application Figure 1 As Figure 3As shown, the pyroelectric lens system includes a lens, at least two PIRs ( Figure 3 Taking 2 PIRs (PIR1, PIR2) as an example for illustration, in actual applications, the number of PIRs can also be other numbers greater than 2), and a processing module.

[0068] It should be understood that the cross-sectional baseline of the lens is arc-shaped, the concave surface of the lens faces the direction of the PIRs, and the convex surface faces the direction of the target to be detected. The at least two PIRs are parallel to each other and are deployed on the same plane on the concave side of the lens.

[0069] It should be understood that the target to be detected can be a person, an animal, or other heat sources that can emit infrared radiation, which can be determined according to the actual situation, and the embodiments of the present application do not specifically limit this.

[0070] Optionally, the at least two PIRs are deployed in the form of single-board separation, and the distance between adjacent PIRs is adjustable.

[0071] Optionally, the at least two PIRs are deployed symmetrically centered with the central axis of the lens as the center of symmetry.

[0072] Wherein, each PIR includes at least two sensing elements, and the at least two sensing elements are arranged in parallel. Moreover, the arrangement direction of the at least two PIRs is consistent with the arrangement direction of at least two sensing elements in each sensing element, that is, the connection line of the at least two sensing elements is parallel to the connection line of the at least two PIRs.

[0073] Wherein, the processing module can be connected to the at least two PIRs in a wired or wireless manner to adjust the distance between adjacent PIRs in the at least two PIRs to implement the detection of the target to be detected.

[0074] In a possible implementation manner, when reducing the distance between adjacent PIRs, the PIRs can be controlled to move towards the central axis of the lens until the distance between adjacent PIRs reaches the target distance; when increasing the distance between adjacent PIRs, the PIRs can be controlled to move away from the central axis of the lens until the distance between adjacent PIRs reaches the target distance.

[0075] It should be understood that the target distance can be determined according to the speed of the target to be detected and a preset mapping relationship. Among them, the distance between adjacent PIRs is proportional to the speed of the target to be detected. It should be understood that an adjustable distance range is preset in the processing module. When the distance between adjacent PIRs is at the adjustable maximum distance within the adjustable distance range, the area of the bright region formed by the pyroelectric lens system is the smallest at this time. As the distance between adjacent PIRs gradually decreases until it reaches the adjustable minimum distance within the adjustable distance range, the area of the bright region formed by the pyroelectric lens system is the largest at this time to meet the detection requirements for low-speed detected objects.

[0076] It should be understood that the bright areas corresponding to different distances between adjacent PIRs will be specifically explained through the embodiments shown later, and will not be elaborated here. Figure 7 and Figure 10 shown later, and will not be elaborated here.

[0077] Optionally, the processing module may also be pre-set with a preset mapping relationship, which includes the corresponding relationship between speed and distance.

[0078] In a possible implementation manner, the pyroelectric lens system further includes a speed adjustment knob. The user can determine the speed of the target detection object according to the actual scenario and perform an adjustment operation on the speed adjustment knob. Correspondingly, the processing module responds to the user's adjustment operation, obtains the speed of the target detection object input by the user, and then searches for the target distance corresponding to the speed of the target detection object in the preset mapping relationship, and adjusts the distance between adjacent PIRs according to the target distance.

[0079] In another possible implementation manner, the pyroelectric lens system further includes a speed detection sensor, which is used to determine the speed of the target detection object and send it to the processing module. Similar to the above implementation manner, the processing module is used to adjust the distance between adjacent PIRs according to the speed of the target detection object and the preset mapping relationship. That is, search in the preset mapping relationship according to the speed of the target detection object detected by the speed detection sensor, determine the target distance corresponding to the speed of the target detection object, and adjust the distance between adjacent PIRs according to the target distance.

[0080] In this implementation manner, the distance between adjacent PIRs in the pyroelectric lens system can be adjusted in real time according to the speed of the target detection object in the actual scenario, so that the pyroelectric lens system can meet the detection requirements of detection objects with different speeds, improving the detection flexibility and accuracy.

[0081] The pyroelectric lens system provided by the embodiment of the present application includes a lens, at least two PIRs, and a processing module. Among them, the cross-sectional baseline of the lens is arc-shaped, at least two PIRs are parallel to each other and are deployed on the same plane on the concave side of the lens. Each PIR includes at least two sensing elements, at least two sensing elements are arranged in parallel, and the connection line of at least two sensing elements is parallel to the connection line of at least two PIRs. The processing module is used to adjust the distance between adjacent PIRs to detect the target detection object, and the distance between adjacent PIRs is proportional to the speed of the target detection object. In this technical solution, the detection requirements for detection objects with different speeds can be met by adjusting the distance between adjacent PIRs, improving the detection accuracy and flexibility. Moreover, this system can be realized only by one lens + at least two PIRs, with low cost, and at least two PIRs are both on the concave side of the lens, reducing the overall volume of the system.

[0082] Optionally, for any adjacent PIRs, when the distance between the adjacent PIRs is the adjustable maximum distance, the pyroelectric lens system is used to detect a set of highest-speed detection objects. Among them, the line connecting the first PIR in the adjacent PIRs and the first partition of the lens is parallel to the line connecting the second PIR in the adjacent PIRs and the second partition of the lens; the first partition and the second partition are adjacent partitions in the lens, and the relative positional relationship between the first partition and the second partition is the same as the relative positional relationship between the first PIR and the second PIR.

[0083] It should be understood that the relative positional relationship between the first partition and the second partition being the same as the relative positional relationship between the first PIR and the second PIR means that if the first partition is on the left side of the second partition, then the first PIR is also on the left side of the second PIR; if the first partition is on the right side of the second partition, then the first PIR is also on the right side of the second PIR.

[0084] In practical applications, the lens can include a single-layer viewing area or a multi-layer viewing area. Figure 4 This is a schematic diagram of the lens viewing area provided by the embodiment of the present application. As Figure 4 shown, the lens includes a double-layer viewing area. The upper viewing area corresponds to a long distance, and the lower viewing area corresponds to a short distance, so as to be able to detect the target detection object at both long and short distances.

[0085] For each layer of the viewing area, the principle of a single core area in the center and symmetry in the middle on the side is satisfied. This principle will be specifically explained through the Figure 5 embodiment shown, and will not be elaborated here.

[0086] Optionally, anti-fooling can also be based on product requirements. A convex structure is defined on the long-axis side of the lens to prevent the lens from being installed backwards by 180 degrees.

[0087] It should be understood that adjacent partitions refer to adjacent partitions in the same layer.

[0088] Furthermore, the Figure 5 embodiment shown is used to further explain each partition.

[0089] Figure 5 This is a schematic diagram of the core positions of the single-layer viewing area provided by the embodiment of the present application. As Figure 5 shown, the lens includes 7 partitions, and the corresponding core positions are core 1, core 2, core 3, core 4, core 2', core 3', and core 4'. Among them, core 1 is on the central axis of the lens, and core 2 and core 2' are symmetrically arranged with the central axis of the lens as the symmetry center; core 3 and core 3' are symmetrically arranged with the central axis of the lens as the symmetry center; core 4 and core 4' are symmetrically arranged with the central axis of the lens as the symmetry center.

[0090] Reference Figure 5 As shown, take the pyroelectric lens system including two PIRs as an example. Assume the core position of core 1 is (0, f), the distance between the first PIR and the second PIR is d1, then the coordinates of the first PIR are (-d1 / 2, 0), and the coordinates of the second PIR are (d1 / 2, 0). Take the angle between the line connecting the center point of the first PIR and core 1 (the core position of the first partition) and the Y-axis as θ1, and the angle between the line connecting the center point of the first PIR and the position of core 2 (the core position of the second partition) and the Y-axis is also θ1, that is, these two connecting lines are parallel to each other.

[0091] Among them, the above f is the focal length of the lens. The relationship among the lens focal length f, the target to be detected, and the sensing element can be achieved through the following formula:

[0092] L / l = W / w = D / f

[0093] Among them, L is the height of the target to be detected, l is the height of the sensing element, W is the width of the target to be detected, w is the width of the sensing element, and D is the distance between the lens and the target to be detected.

[0094] Deriving according to the above formula, we can get:

[0095] f = D×l / L = D×w / W

[0096] For example, if the height of the sensing element is 2mm, the detection target is 20M, and the target height is 1.7M, then f = 20×2 / 1.7 = 23.5mm.

[0097] It can be seen from the above formula that when the distance between the lens and the target to be detected is farther, the distance between the lens surface and the PIR (focal length f) is farther.

[0098] Assume the coordinates of core 2 are (x2, y2), and x2 and y2 can be expressed by the following formula:

[0099] x2 = (d1 + sqrt(d1 2 -(tan(θ1) 2 +1)×(d1 2 -4×tan(θ1) 2 ×f 2 )) / (2×(tan(θ1) 2 +1))

[0100] y2 = (x2 - d1 / 2) / tan(θ1)

[0101] And so on, take the angle between the line connecting the first PIR and core 2 (the core position of the first partition) and the Y-axis as θ2, and the angle between the line connecting core 3 (the core position of the second partition) and the second PIR and the Y-axis is also θ2, that is, these two connecting lines are parallel to each other. According to the above formula and rules, the coordinates of other core positions can be determined in turn.

[0102] Figure 6 This is a schematic diagram of the propagation principle of infrared rays provided by the embodiments of the present application. As Figure 6 shown, when the edge incident angle (the angle β between the line connecting the edge of the local lens and the center of the PIR and the normal of the PIR surface) is large, there are problems of high reflection ratio and low incident efficiency, which will affect the accuracy and reliability of detection.

[0103] Based on Figure 6 the principle shown, the zoning of the lens needs to meet at least one of the following conditions:

[0104] Condition 1: The ratio of the width to the height of a single zone is controlled near 1:2, and the maximum does not exceed 1:8.

[0105] Condition 2: β is not greater than 60 degrees.

[0106] It should be understood that the lens zoning determined in the above manner ensures that the area of a single zone is large enough to improve the long-distance detection ability. Moreover, it can also ensure that enough infrared rays enter the PIR to ensure the accuracy and reliability of detection.

[0107] At the same time, the connection line between the first PIR in the adjacent PIRs and the first zone of the lens is parallel to the connection line between the second PIR in the adjacent PIRs and the second zone of the lens, so that the bright areas projected by the first PIR through the lens and the bright areas projected by the second PIR through the lens overlap and are parallel. This parallel setting enables the first PIR and the second PIR to perform signal cross-judgment within the bright area range to improve the detection accuracy. At the same time, the signals of the first PIR and the second PIR can also be superimposed to enhance the signal detection.

[0108] It should be understood that the specific implementation manner will be explained through Figure 19 the embodiments shown and will not be elaborated here.

[0109] Taking the pyroelectric lens system including two PIRs as an example, when the distance between the adjacent PIRs is the adjustable maximum distance, that is, the bright area distribution in the set highest-speed scenario can be as Figure 7 shown.

[0110] Figure 7 This is the schematic diagram of the bright area distribution in the set highest-speed scenario provided by the embodiments of the present application Figure 1 . As Figure 7 shown, Figure 7 part (a) of [] is the detection sector formed by the left PIR through the lens, and the bright areas corresponding to the two sensing elements in the left PIR are included in this detection sector; similarly, Figure 7Part (b) is the detection sector formed by the right PIR through the lens. The detection sector includes the bright areas corresponding to the two sensing elements in the right PIR. The bright areas included in these two detection sectors are highly coincident and parallel. Combine them, and after combination, it is represented as in Figure 7 Part (c).

[0111] In practical applications, the included angle α between adjacent viewing areas also affects the detection effect. Figure 8 This is a schematic diagram of the included angle between adjacent viewing areas provided by the embodiment of the present application. As Figure 8 shown, the dark area is the bright area of one sensing element in the PIR, and the light area is the bright area of another sensing element in the PIR. The included angle between adjacent viewing areas is α.

[0112] In practical applications, assuming that the moving speed of the target detection object is v, the detection distance (the distance between the lens and the target detection object) is D, the line frequency is m, and the angular frequency is n, then the line frequency and angular frequency can be calculated by the following formulas:

[0113] m = v / (2×D×tan(α / 2))

[0114] n = 2π×m

[0115] According to the above formulas, it can be obtained that the faster the moving speed of the target detection object, the higher the angular frequency; the closer the detection distance, the higher the angular frequency.

[0116] Figure 9 This is a schematic diagram of the relationship between the PIR responsivity and the frequency provided by the embodiment of the present application. As Figure 9 shown, as the frequency gradually increases, the PIR responsivity K decreases, that is, the PIR signal value decreases, resulting in a lower detection rate for high-speed detection objects. In order to improve the detection effect of high-speed detection objects, the number of partitions needs to be reduced, that is, the α angle (the included angle between adjacent viewing areas) needs to be large enough to reduce the frequency. In practical applications, the α angle can be in the range of 20~30 degrees. For example, taking a detection distance of 20 meters as an example, when the speed of the target detection object is 10 m / s, the angular frequency is 5.8 HZ, and when α is defined as 15 degrees, the angular frequency is 12 HZ, exceeding the responsivity of the specification. After calculating the difference, it is found that the difference in the PIR responsivity between the two is more than 3 times.

[0117] For low-speed target detection objects, such as 3 m / s, due to the large α, when the distance between the target detection object and the pyroelectric lens system is far, the time for the target detection object to move to the next bright area at a speed of 3 m / s is too long. Therefore, by reducing the distance between adjacent PIRs, the parallel detection sectors gradually become non-parallel and gradually stagger. Figure 10 This is a schematic diagram of the bright area distribution in the set lowest-speed scenario provided by the embodiment of the present application. As Figure 10As shown, in the set lowest speed scenario, when the distance between adjacent PIRs is reduced to d1 / 2, a viewing area with approximately double the bright area and an approximately uniform distribution can be obtained, and the detection frequency can be doubled to adapt to low-speed target objects. Since the size of the partitioned light-transmitting aperture remains unchanged, the detection distance will not be reduced due to the decrease in the number of partitions, ensuring the long-distance detection ability.

[0118] In the prior art, most often one PIR + lens is used to detect target objects within the detection range. When the requirement for the detection range changes, it is generally achieved by replacing the lens. Therefore, for a device, there is generally only one field of view range.

[0119] Some solutions can also be implemented as multiple PIRs + lenses, that is, each PIR is equipped with its own lens to achieve the superposition of the field of view range (the fields of view can be stitched or partitioned. For example, one PIR + lens can be used to achieve large-range detection, and one PIR + lens can be used to achieve local small-range detection).

[0120] Figure 11 It is a schematic structural diagram of 2 PIRs + lenses in the prior art. As Figure 11 shown, the two PIRs achieve the stitching of the detection range. When the requirement for the field of view angle changes, one of the PIRs is removed to achieve the change in the detection range. For example, the original angle of the detection range is θ1 + θ2, and after removing one, it becomes θ1 or θ2.

[0121] However, the angle of the detection range in the above zoom scheme changes greatly and the continuity is poor. To solve the above problems, the prior art increases the number of PIRs, and then achieves a small change in the angle of the detection range by removing a small number of PIRs.

[0122] However, the above scheme requires a large number of PIRs and the structure is relatively complex, which cannot be compatible with most products and the feasibility is poor.

[0123] In this application, the processing module can also adjust the distance between adjacent PIRs to adjust the angle of the field of view, that is, to achieve zooming.

[0124] Figure 12 It is a schematic diagram of the edge incident angle provided by the embodiment of this application. As Figure 12 shown, the edge incident angles are γ1 and γ2 respectively, and the coordinates of the core 4 are (a, b). Then γ1 = a × tan((a - d1 / 2) / b), γ2 = a × tan((a + d1 / 2) / b), and the detection field of view range is 2max(γ1, γ2).

[0125] As the processing module adjusts the distance between adjacent PIRs, the angle between the connection line from the edge PIR to the edge core in at least two PIRs and the Y-axis (edge incident angle) also changes, that is, the detection field of view changes, and thus the zoom effect can be achieved. When d1 becomes smaller, the field of view angle becomes smaller; when d1 becomes larger, the field of view angle becomes larger.

[0126] It should be understood that the pyroelectric lens system can also be provided with a zoom knob. The user can determine the detection field of view according to the actual scenario and perform a rotation operation on the zoom knob. Correspondingly, the processing module responds to the user's rotation operation, obtains the detection field of view set by the user, then searches for the target distance corresponding to the detection field of view in the preset mapping relationship, and adjusts the distance between adjacent PIRs according to the target distance.

[0127] That is to say, the preset mapping relationship can include not only the correspondence between speed and distance, but also the relationship between the field of view and distance.

[0128] Optionally, in some embodiments, the pyroelectric lens system further includes an opaque baffle, and the opaque baffle is detachably placed on at least one side of either side of any PIR.

[0129] Optionally, the height of the opaque baffle can be adjusted.

[0130] Based on Figure 5 , taking the pyroelectric lens system including two PIRs as an example for illustration, Figure 13 FIG. is the position schematic diagram of the opaque baffle provided by the embodiment of the present application. As Figure 13 shown, an opaque baffle can be placed between the two PIRs to block the incident light of core 3 and core 4 on the right side for the first PIR, thereby realizing the change of the central side field of view γ1; at the same time, it can also block the incident light of core 3' and core 4' on the left side for the second PIR, thereby realizing the change of the central side field of view γ2. Similarly, an opaque baffle can also be added on the outside. For example, Figure 13 the opaque baffle on the right side of the second PIR in, blocks the incident light of core 4 on the right side for the second PIR, thereby realizing the change of the central side field of view γ1, realizing the zoom function, and the detection field of view range is 2max(γ1, γ2).

[0131] Optionally, in some embodiments, a silicone filter is deployed above each PIR.

[0132] It should be understood that the material of the filter can also be other materials, which can be determined according to the actual situation, and the embodiments of the present application do not specifically limit this.

[0133] In practical applications, the filter can be a 5.5um flat-pass or an 8 - 14um band-pass, and is fixed on the PIR in the form of being embedded in silicone. The gap between the filter and the PIR surface is between 0.1 - 2mm, and it should not be too large. If it is too large, it will cause the occlusion of the edge detection field of view to become smaller.

[0134] Figure 14 Schematic structure of the pyroelectric lens system provided by the embodiment of the present application Figure 2 As Figure 14 shown, the pyroelectric lens system further includes a filter.

[0135] Figure 15 Schematic diagram of the structure of PIR + filter provided by the embodiment of the present application. As Figure 15 shown, the filter can completely cover the sensing elements in the PIR.

[0136] In the above embodiment, by installing a filter on the PIR surface, a noise reduction effect can be achieved in outdoor application scenarios, and the false alarm rate can be reduced.

[0137] Optionally, the generatrix of the curved surface contour of the lens can be a spherical surface.

[0138] On the basis of Figure 14 , Figure 16 Spatial coordinate schematic diagram of the pyroelectric lens system provided by the embodiment of the present application. As Figure 16 shown, the distance between the central positions of the two PIRs is the distance d1 between the two PIRs, and the linear distance between the PIR surface and the most convex point of the lens is the focal length f.

[0139] Considering that the effective area of the cylindrical surface is larger than that of the spherical surface, based on the idea of maximizing the light passing aperture, the generatrix of the curved surface contour of the lens can also be a cylindrical surface. There is no horizontal dispersion, and the vertical dispersion is achieved by deploying at least two PIRs with a size smaller than the sensing elements on the central plane of the lens.

[0140] When the generatrix of the curved surface contour of the lens is a cylindrical surface, it has more advantages in light collection, and can allow more infrared rays to pass through the lens and be focused on the PIR to improve the detection accuracy and reliability.

[0141] Optionally, in some embodiments, the inner wall of the lens is a Fresnel focusing structure.

[0142] Figure 17 Schematic diagram of the inner wall of the lens provided by the embodiment of the present application. As Figure 17 shown, in practical applications, the tooth height is not higher than 0.2mm, the thickness of the base surface is not higher than 0.5mm, generally defined as 0.4 - 0.55mm, and with the addition of the tooth height, the overall height is not higher than 0.7mm.

[0143] In this embodiment, since the inner wall of the lens is a Fresnel focusing structure, it can effectively reduce the overall thickness of the lens, improve the light transmittance of the lens, so that more infrared rays can enter the PIR, and improve the accuracy and reliability of detection.

[0144] Figure 18 This is a three-dimensional schematic diagram of the pyroelectric lens system provided by the embodiment of the present application. As Figure 18 shown, the lens of the pyroelectric lens system is double-layer partitioned.

[0145] Based on the pyroelectric lens system involved in any of the above embodiments, next, an explanation of the method for detecting a target detection object based on this pyroelectric lens system will be given.

[0146] Figure 19 This is a flowchart of the method for detecting a target detection object provided by the embodiment of the present application. As Figure 19 shown, the execution subject of this method is the processing module of the pyroelectric lens system involved in any of the above embodiments, and this method can be implemented through the following steps:

[0147] S191. Determine the target distance according to the speed of the target detection object and the preset mapping relationship.

[0148] Among them, the speed of the target detection object is obtained in response to the user's adjustment operation or collected according to the speed sensor. The preset mapping relationship includes the corresponding relationship between speed and distance, and the target distance is proportional to the speed of the target detection object.

[0149] In a possible implementation manner, the pyroelectric lens system further includes a speed adjustment knob. The user can determine the speed of the target detection object according to the actual scenario and perform an adjustment operation on the speed adjustment knob. Correspondingly, the processing module responds to the user's adjustment operation, obtains the speed of the target detection object input by the user, and then searches for the target distance corresponding to the speed of the target detection object in the preset mapping relationship.

[0150] Exemplarily, for example, in the field of wildlife detection, according to the living habits of wild animals generated in a fixed area, determine their average speed. Before placing the surveillance camera in this fixed area, adjust the speed adjustment knob according to this average speed so that the distance between adjacent PIRs in the pyroelectric lens system can be adjusted according to this average speed subsequently.

[0151] In another possible implementation, the pyroelectric lens system further includes a speed detection sensor, which is used to determine the speed of the target detection object. After detecting the speed of the target detection object, the speed detection sensor sends the speed of the target detection object to the processing module, and the processing module looks up in the preset mapping relationship according to the speed of the target detection object to determine the target distance corresponding to the speed of the target detection object.

[0152] In practical applications, the speed detection sensor will determine the speed of the moving object in real time. The moving object can be the target detection object or a non-target detection object. Then, according to the detected speed of the moving object, the target speed is actually determined, so as to subsequently adjust the distance between adjacent PIRs in the pyroelectric lens system in real time according to the target speed, so as to better meet the detection requirements for target detection objects with different speeds and improve the detection flexibility and accuracy.

[0153] S192. Adjust the distance between adjacent PIRs in the pyroelectric lens system according to the target distance.

[0154] In one possible implementation, when reducing the distance between adjacent PIRs, the PIR can be controlled to move towards the lens central axis direction until the distance between adjacent PIRs reaches the target distance; when increasing the distance between adjacent PIRs, the PIR can be controlled to move away from the lens central axis direction until the distance between adjacent PIRs reaches the target distance.

[0155] S193. Detect the target detection object through the pyroelectric lens system.

[0156] For the set highest-speed scenario, that is, the line connecting the first PIR in the adjacent PIRs and the first partition of the lens is parallel to the line connecting the second PIR in the adjacent PIRs and the second partition of the lens; the first partition and the second partition are adjacent partitions in the lens, and the relative position relationship between the first partition and the second partition is the same as the relative position relationship between the first PIR and the second PIR. The bright area distribution can refer to Figure 7 the schematic diagram shown.

[0157] Figure 20 This is the schematic diagram of the electrical signal in the set highest-speed scenario provided by the embodiment of the present application. As Figure 20 shown, on the basis of Figure 7 when the target detection object tangentially enters the detection area and continuously moves until it exits the detection area, two PIRs will generate electrical signals at the same time. Ideally, the two electrical signals will form waveforms with the same type and the same phase. Among them, the blue line is the waveform formed by the left PIR, and the red line is the waveform formed by the right PIR.

[0158] Among them, Figure 20The abscissa of the waveform shown is time, and the ordinate is amplitude.

[0159] Based on the above waveform characteristics, signal cross-judgment can be performed on the electrical signals generated by PIRs to improve the detection accuracy.

[0160] Specifically, start timing when any PIR generates an electrical signal. Before the cumulative time obtained by timing reaches the preset time, determine whether other PIRs generate electrical signals; if any other PIR does not generate an electrical signal, it is determined that no target detection object is detected; if all other PIRs generate electrical signals, then superimpose the electrical signals generated by each PIR, and detect the target detection object according to the superimposed electrical signal.

[0161] In the set highest-speed scenario, if all PIRs generate electrical signals within the preset time, it means that all PIRs have detected infrared radiation changes. At this time, this electrical signal is reliable, and the target detection object can be detected based on the electrical signals generated by all PIRs; if some PIRs generate electrical signals within the preset time, but some PIRs do not generate electrical signals, it means that there may be malfunctions of PIRs or false detections caused by environmental factors. At this time, the electrical signal is not reliable, and it is determined that no target detection object is detected. By this way, signal cross-judgment is realized, and the accuracy of detecting the target detection object according to the electrical signal is further improved.

[0162] Furthermore, after determining that the electrical signal is reliable, the electrical signals generated by all PIRs can also be superimposed to form an effective signal gain, and then the target detection object is detected according to the superimposed electrical signal. The signal-to-noise ratio is improved, and the detection rate is effectively improved.

[0163] It should be understood that Figure 20 the yellow dashed line in

[0164] Furthermore, still in the above highest-speed scenario, an opaque baffle can be detachably placed on the left side of the leftmost PIR and on the right side of the rightmost PIR to block the incident light of the leftmost partition of the lens of the pyroelectric lens system for the remaining PIRs except the rightmost PIR, and to block the incident light of the rightmost partition of the lens of the pyroelectric lens system for the remaining PIRs except the rightmost PIR. At this time, the incident light of the rightmost partition of the lens can only enter the leftmost PIR, and the incident light of the leftmost partition of the lens can only enter the rightmost PIR.

[0165] In Figure 7 Based on the embodiment shown, after the opaque baffle is detachably placed on the left side of the leftmost PIR and on the right side of the rightmost PIR, the bright area distribution can be represented by Figure 21 for presentation. Figure 21 This is the schematic diagram of the bright area distribution in the set highest-speed scenario provided by the embodiment of the present applicationFigure 2 As shown in Figure 21 , the left PIR does not construct the right core 4 viewing area, and the right PIR does not construct the left core 4' viewing area. At this time, the entire detection area can be divided into three parts. Among them, part 1 includes the single-response sector of the left PIR, part 2 includes the double-response sectors of the left and right PIRs, and part 3 is the single-response sector of the right PIR.

[0166] In this scenario, after detecting the target object, the position of the target object is determined according to the PIR that generates the electrical signal.

[0167] Taking Figure 21 as an example, after determining that the target object is detected according to the electrical signal, if both PIRs generate electrical signals, it is determined that the target object is in part 3. If the electrical signal is generated by the left PIR, it is determined that the target object is in part 1. If the electrical signal is generated by the right PIR, it is determined that the target object is in part 3.

[0168] In this embodiment, by determining the approximate position of the target object, it can help the monitoring camera to better photograph the target object and provide assistance for the subsequent operations of the monitoring camera.

[0169] It should be understood that in the highest-speed scenario, if the bright areas of all PIRs are parallel and coincident, the detection accuracy and detection rate can be increased through signal mutual judgment and superposition; if the partial bright areas of all PIRs are not coincident by placing opaque baffles, the position of the target object can be determined according to the PIR that generates the electrical signal.

[0170] Optionally, based on Figure 10 shown in the lowest-speed scenario, the viewing areas of the left PIR and the right PIR do not overlap and are parallel. When the target object invades tangentially (horizontally from left to right or from right to left as shown in the figure), there is a phase difference in the signals of the two PIRs, and the two PIRs need to detect the target object through their respective judgment logics.

[0171] Based on Figure 10 shown in the lowest-speed scenario, Figure 22 is the schematic diagram of the electrical signal in the set lowest-speed scenario provided by the embodiment of the present application. As shown in Figure 22 , Figure 22 in a, the target object walks tangentially through the viewing areas corresponding to at least one left PIR and the viewing areas corresponding to the right PIR, and b is passing only through the right PIR (local walking).

[0172] Among them, Figure 22 the abscissa of the waveform shown is time, and the ordinate is amplitude.

[0173] Furthermore, in the scenario shown in Figure 7 and Figure 10In the scenes shown, the low-speed detection objects are detected respectively, and the electrical signals generated by the PIR can be represented by Figure 23 and Figure 24 .

[0174] Figure 23 is the electrical signal generated for the low-speed detection object in the highest-speed scene provided by the embodiment of the present application. Figure 24 is the electrical signal generated for the low-speed detection object in the lowest-speed scene provided by the embodiment of the present application. As Figure 23 and Figure 24 shown, in the lowest-speed scene, the bright and dark areas are evenly distributed, there is no large blank blind area, and the angular frequency distribution is high. Compared with the highest-speed scene, for the low-speed detection object, a detection effect twice that of it can be achieved, and the detection rate is high.

[0175] Among them, Figure 23 and Figure 24 the abscissa of the waveform shown is time, and the ordinate is amplitude.

[0176] The detection method of the target detection object provided by the embodiment of the present application is applied to the processing module in the pyroelectric lens system. According to the speed of the target detection object and the preset mapping relationship, the target distance is determined; according to the target distance, the distance between adjacent passive infrared detectors (PIRs) in the pyroelectric lens system is adjusted; through the pyroelectric lens system, the target detection object is detected. Among them, the speed of the target detection object is obtained in response to the user's adjustment operation or collected according to the speed sensor, the preset mapping relationship includes the corresponding relationship between speed and distance, and the target distance is proportional to the speed of the target detection object. In this technical solution, considering that the requirements for the bright areas of the pyroelectric lens system by target detection objects with different speeds are different, the distance between adjacent PIRs can be adjusted according to the manually set speed or the speed collected by the speed sensor to generate a bright area using the speed of the target detection object, so as to improve the detection effect on the target detection object.

[0177] Optionally, in some embodiments, the present application also provides a monitoring camera, and the pyroelectric lens system is configured in the monitoring camera.

[0178] Finally, it should be noted that: those skilled in the art will easily think of other implementation schemes of the present invention after considering the specification and practicing the invention disclosed herein. The present invention aims to cover any variations, uses or adaptations of the present invention, and these variations, uses or adaptations follow the general principles of the present invention and include the common general knowledge or conventional technical means in the technical field not disclosed in the present invention. It is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.

Claims

1. A pyroelectric lens system, characterized in that: include: A lens, at least two passive infrared detectors PIR and a processing module; The cross-sectional baseline of the lens is in an arc shape, and the at least two PIRs are parallel to each other and are arranged on the same plane on the concave side of the lens; Each PIR comprises at least two sensing elements, the at least two sensing elements are arranged in parallel, and a line connecting the at least two sensing elements is parallel to a line connecting the at least two PIRs; The processing module is used to adjust the distance between adjacent PIRs to detect the target object, and the distance between adjacent PIRs is proportional to the speed of the target object.

2. The system according to claim 1, characterized in that For any adjacent PIRs, when the distance between the adjacent PIRs is the maximum adjustable distance, a line connecting a first PIR among the adjacent PIRs and a first subarea of ​​the lens is parallel to a line connecting a second PIR among the adjacent PIRs and a second subarea of ​​the lens; The first partition and the second partition are adjacent partitions in the lens, and a relative positional relationship between the first partition and the second partition is the same as a relative positional relationship between the first PIR and the second PIR.

3. The system according to claim 1 or 2, characterized in that: The pyroelectric lens system further comprises a light-proof baffle, which is detachably placed on at least one of the two sides of any PIR.

4. The system according to claim 1 or 2, characterized in that: The pyroelectric lens system further comprises a speed detection sensor, which is used to determine the speed of the target detection object and send it to the processing module; The processing module is used to adjust the distance between the adjacent PIRs according to the speed of the target detection object and a preset mapping relationship, wherein the preset mapping relationship includes a corresponding relationship between speed and distance.

5. The system according to claim 1 or 2, characterized in that: The curved surface profile generatrix of the lens is a cylindrical surface, and the at least two PIRs are deployed on the center plane of the lens.

6. The system according to claim 1 or 2, characterized in that: A silica gel filter is deployed above each PIR.

7. The system according to claim 1 or 2, characterized in that: The inner wall of the lens is a Fresnel focusing structure.

8. A method for detecting a target object, characterized in that: A processing module applied to a pyroelectric lens system according to any one of claims 1 to 7, the method comprising: Determine the target distance according to the speed of the target detection object and a preset mapping relationship, wherein the speed of the target detection object is obtained in response to an adjustment operation of the user or is acquired according to a speed sensor, and the preset mapping relationship includes a corresponding relationship between the speed and the distance, and the target distance is proportional to the speed of the target detection object; According to the target distance, adjusting the distance between adjacent passive infrared detectors PIR in the pyroelectric lens system; The target object is detected by the pyroelectric lens system.

9. The method according to claim 8, characterized in that When the pyroelectric lens system is a structure as shown in claim 2, and the distance between the adjacent PIRs is an adjustable maximum distance, the target detection object is detected by the pyroelectric lens system, including: When any PIR generates an electrical signal, the timing is started, and before the accumulated time obtained by the timing reaches a preset time, it is determined whether other PIRs generate electrical signals; If any other PIR does not generate an electrical signal, it is determined that the target detection object is not detected; If the other PIRs all generate electrical signals, the electrical signals generated by each PIR are superimposed, and the target object is detected according to the superimposed electrical signals.

10. The method according to claim 8, characterized in that When the pyroelectric lens system is of the structure as shown in claim 2, and a light-proof baffle is detachably placed on the left side of the leftmost PIR and on the right side of the rightmost PIR, so as to shield the incident light of the leftmost subarea of ​​the lens of the pyroelectric lens system for the remaining PIRs except the rightmost PIR, and shield the incident light of the rightmost subarea of ​​the lens of the pyroelectric lens system for the remaining PIRs except the leftmost PIR, the method further comprises: After the target object is detected, the position of the target object is determined according to the PIR that generates the electrical signal.

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