An intrusion detector based on microlens array and single-pixel imaging
By using microlens arrays and single-pixel imaging, the intrusion detector solves the problems of easy beam identification and limited beam width of laser beam detectors, achieving large field of view and high resolution intrusion detection. It is suitable for micro targets and non-cooperative areas, reducing the false alarm rate and the number of devices and costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING INST OF TECH
- Filing Date
- 2023-09-26
- Publication Date
- 2026-07-21
AI Technical Summary
Existing laser beam intrusion detectors have limitations such as easily identifiable beam positions, limited beam width, and high costs. They are not suitable for micro-targets or non-cooperative areas, and require the placement of light walls at both ends in trusted areas.
An intrusion detector based on microlens array and single-pixel imaging is used. It collects light signals through microlens array and uses single-pixel imaging algorithm to achieve high-speed imaging. Combined with servo alarm, it makes intrusion judgment. The transceiver integrated design is suitable for non-cooperative target areas.
It achieves target imaging with a large field of view and high resolution, reduces the false alarm rate and the missed detection rate, is suitable for non-cooperative target areas, and saves on the number of devices and operation and maintenance costs.
Smart Images
Figure CN117058828B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of intrusion detection technology, specifically relating to an intrusion detector based on microlens arrays and single-pixel imaging. Background Technology
[0002] Most existing area security measures employ infrared laser beam intrusion detection, which consists of a light source, a detector, a receiver, and a transmitter. The light source emits multiple beams of infrared laser light, which are then directed at each other in parallel to form a light wall. The light source and detector are arranged in pairs at equal intervals, with the beams parallel. The transmitter and receiver are placed at opposite ends of the light wall.
[0003] The above detection method has the following problems:
[0004] (1) The beam position is obvious, and the position of the optical path can be deduced from the position of the light source and the detector. It cannot detect intelligent intruders that actively determine the position of the beam.
[0005] (2) The beamwidth of the laser beam is extremely limited, and the spacing between parallel beams is relatively large. Reducing the beam spacing requires increasing the number of parallel beams, so the cost increases linearly with the number of parallel beams, making it unsuitable for micro-drones, micro-bionic robots, and other small targets.
[0006] (3) The transmitter and receiver are located at opposite ends of the optical wall. This requires close cooperation between the light source and detector at both ends of the optical wall. Both ends of the optical wall must be trusted and secure areas.
[0007] Therefore, the aforementioned laser beam detector is not suitable for non-cooperative target areas where one end is a location with unknown security. Summary of the Invention
[0008] The present invention aims to provide an intrusion detector based on microlens array and single-pixel imaging, and aims to solve the technical problems existing in the prior art.
[0009] To achieve the above objectives, the present invention provides the following technical solution: an intrusion detector based on a microlens array and single-pixel imaging, comprising a transmitter and a receiver. The transmitter includes a central controller, a data image processor, a semiconductor laser, a phase modulator, a spatial light modulator, and a collimating lens; the receiver includes a microlens array, a photon detector, a data image processor, and a servo alarm.
[0010] In another preferred embodiment of the invention, the transmitter and receiver are integrated into one unit. Installation and use are simple.
[0011] In another preferred embodiment of the invention, the semiconductor laser emits laser light in the near-infrared band at 800nm. This wavelength is invisible to the naked eye, providing strong concealment. Simultaneously, it is easily integrated with laser night vision systems.
[0012] In another preferred embodiment of the invention, both the microlens array and the photon detector are provided in pairs. The signals from the paired microlenses are temporally correlated, thus exhibiting strong anti-interference capabilities.
[0013] In another preferred embodiment of the present invention, the photon detector is a detector with photon resolution capability, which is an avalanche photodiode detector operating in Geiger mode or a superconducting single-photon detector with a superconducting mechanism.
[0014] In another preferred embodiment of the present invention, the servo alarm includes an image input interface, an alarm feedback output interface, a siren drive output interface, a warning light drive output interface, an alarm message output interface, and a discrimination algorithm. It can perform intrusion signal discrimination and alarm activation.
[0015] In another preferred embodiment of the present invention, the specific usage process is as follows:
[0016] The central controller sends a control signal to the semiconductor laser, causing the semiconductor laser to emit laser light. At the same time, the data image processor sends a modulation signal to the phase modulator to change the modulation mode on the spatial light modulator. The light signal modulated by the spatial light modulator is output through the collimating lens, reaches the measured area or the measured object, and returns an echo signal.
[0017] The echo signal returned from the measured area or the measured object is received by the microlens array, then detected by the photon detector, and the detection signal of the photon detector is received and processed by the data image processor.
[0018] When the test signal emitted by the data image processor is a background test signal, a background image of the target scene is formed; when the test signal emitted by the data image processor is a real-time test signal, a real-time image of the target scene is formed; and the data image processor sends the background image and the real-time image of the target scene to the servo alarm through the image input interface, and the discrimination algorithm in the servo alarm determines whether there is an intrusion.
[0019] If an intrusion is detected, the alarm feedback output interface will be used to send a signal to the central controller, which will then initiate an intrusion response strategy and begin target scene tracking and detection under intrusion conditions. Simultaneously, the alarm siren, alarm light, and alarm record text will be output through the siren drive output interface, the alarm light drive output interface, and the alarm text output interface, respectively.
[0020] In another preferred embodiment of the invention, the image acquisition by the data image processor uses a single-pixel imaging algorithm.
[0021] In another preferred embodiment of the present invention, the ratio of the background test signal to the real-time test signal is 1:5 to 1:100. The discrimination threshold can be flexibly adjusted according to the control level.
[0022] In another preferred embodiment of the present invention, the discrimination algorithm of the servo alarm is as follows: set a threshold ε, calculate the difference δ between the real-time imaging of the target scene and the background imaging of the target scene, and then calculate the function f(δ). If f(δ) > ε, it is determined that there is an intrusion; otherwise, it is determined that there is no intrusion.
[0023] This invention features an integrated transceiver design that enables high-speed imaging of the inspected area through efficient reflected light collection via a microlens array and a highly efficient single-pixel imaging algorithm. This avoids the limitations of narrow coverage and susceptibility to evasion inherent in laser-based intrusion detectors, significantly reducing false alarm rates and enhancing the adaptability and robustness of the intrusion detector.
[0024] It can achieve scene monitoring through the emission of a three-dimensional cone-shaped beam and the inversion algorithm of diffuse reflection echo signals from the target scene. Due to the use of a microlens array, it can achieve target imaging with a large field of view and equal resolution, solving the problem of missed detection caused by the narrow beam of laser through-beam intrusion detectors. Furthermore, due to its integrated transceiver design, it eliminates the need for remote deployment, making it more suitable for intrusion detection in non-cooperative target areas or security control in known areas.
[0025] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0026] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0027] Figure 1 This is a schematic diagram of an embodiment of this application.
[0028] Figure 2 This is a schematic diagram of the alarm server in the embodiments of this application.
[0029] Figure 3 This is a flowchart of the background imaging of the target scene in the embodiments of this application.
[0030] Figure 4 This is a flowchart of real-time imaging of the target scene in an embodiment of this application.
[0031] Figure 5This is a timing logic diagram of the background test timing signal and the real-time test timing signal in the embodiments of this application.
[0032] Figure 6 This is a flowchart of the discrimination algorithm in the alarm server in the embodiments of this application.
[0033] Figure 7 This is a schematic diagram of the experimental application of this application. Detailed Implementation
[0034] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.
[0035] Semiconductor laser: LASER
[0036] Phase modulator: φ
[0037] Spatial light modulator: SLM
[0038] Collimating lens: LEN
[0039] Microlens arrays: ML1, ML2
[0040] Photon detectors: PD1, PD2
[0041] Figure 2 31 is the image input interface, 32 is the alarm feedback output interface, 33 is the siren drive output interface, 34 is the alarm light drive output interface, 35 is the alarm message output interface, and 36 is the discrimination algorithm.
[0042] This invention provides an intrusion detector based on a microlens array and single-pixel imaging, such as... Figure 1 As shown, it includes a transmitter and a receiver, which are integrated into one unit.
[0043] The transmitter includes a central controller, a data image processor, a semiconductor laser, a phase modulator, a spatial light modulator, and a collimating lens.
[0044] When in use, the semiconductor laser emits laser light in the near-infrared band at 800nm, which is invisible to the naked eye and has strong stealth capabilities.
[0045] The receiver includes a microlens array, a photon detector, a data image processor, and a servo alarm, with the microlens array and photon detector each configured as a pair.
[0046] The photon detector employs a detector with photon resolution capability, operates with high-speed repetition frequency pulses, and uses either an avalanche photodiode detector operating in Geiger mode or a superconducting single-photon detector with a superconducting mechanism.
[0047] Combination Figure 2 As shown, the servo alarm includes an image input interface, an alarm feedback output interface, a siren drive output interface, a warning light drive output interface, an alarm message output interface, and a discrimination algorithm.
[0048] The specific usage process of the intrusion detector based on microlens array and single-pixel imaging is as follows:
[0049] Inside the transmitter:
[0050] The central controller sends control signals to the semiconductor laser, causing it to emit laser light. Simultaneously, the data image processor sends modulation signals to the phase modulator, changing the modulation mode on the spatial light modulator. The light signal modulated by the spatial light modulator passes through a collimating lens, reaches the measured area or object, and returns as an echo signal.
[0051] Within the receiving end:
[0052] The echo light signal returned from the measured area or object is first received by a pair of microlens arrays, and then detected by a pair of photon detectors. The detection signal of the photon detectors is received and processed by a data image processor, which uses a single-pixel imaging algorithm for image reception.
[0053] Detect non-invasive target scenes to form background images of the target scenes, and combine them with... Figure 3 As shown, a data image processor sends four control signals with encoded parameters φ = 0, φ = π / 2, φ = π, and φ = 3π / 2 to a spatial light modulator. Photon count data are recorded by a microlens array and a single-photon detector, respectively. After weighted calculation of the four types of data, the background image I0(x, y) of the target scene is recovered by inverse Fourier transform.
[0054] Real-time imaging of the target scene is formed by utilizing real-time detection signals, combined with Figure 4 As shown, a data image processor sends four control signals with encoded parameters φ = π / 4, φ = 3π / 4, φ = 5π / 4, and φ = 7π / 4 to a spatial light modulator. Photon count data are recorded by a microlens array and a single-photon detector, respectively. After weighting the four types of data, an inverse Fourier transform is used to recover the real-time image I1(x, y) of the target scene.
[0055] The data image processor then uses the background image and real-time image of the target scene to send them to the servo alarm via the image input interface. The servo alarm then uses its built-in discrimination algorithm to determine whether an intrusion has occurred.
[0056] If an intrusion is confirmed, feedback information is sent to the central controller via the alarm feedback output interface. The central controller then activates the intrusion response strategy, initiating target scene tracking and detection under intrusion conditions. Simultaneously, the siren driver output interface activates the siren, and the sirens driver output interface activates the sirens to achieve the alarm purpose. Finally, the alarm log text is output via the alarm text output interface.
[0057] Combination Figure 5 As shown, both the baseline test timing signal and the real-time test timing signal are true when they are high. When the baseline test timing signal is true, the phase detector is locked sequentially at φ = 0, φ = π / 2, φ = π, and φ = 3π / 2. When the real-time test timing signal is true, the phase detector is locked sequentially at φ = π / 4, φ = 3π / 4, φ = 5π / 4, and φ = 7π / 4. The ratio of the baseline test timing signal to the real-time test timing signal is 1:5 to 1:100; in this embodiment, a ratio of 1:9 is selected.
[0058] Combination Figure 6 As shown, the discrimination algorithm of the servo alarm is to set a threshold ε, which is a decimal between 0.01 and 0.0001, depending on the security requirements of the intrusion detection.
[0059] Calculate the difference δ between the background image I0(x,y) and the real-time image I1(x,y) of the target scene, where δ = I1(x,y) - I0(x,y), and then calculate the function f(δ), which takes the second norm of the matrix.
[0060] If f(δ) > ε, then it is determined that an intrusion exists; otherwise, it is determined that no intrusion exists.
[0061] experiment:
[0062] Experiments were conducted on multi-array detection applications to achieve coverage of a location region with a distance of D and a length of L.
[0063] Specifically, given L = 75m, D = 30m, and a beam divergence angle of 60°, three intrusion detectors are sufficient to cover the area at L = 75m; (Further details to be added) Figure 7 As shown, three intrusion detectors of the same specifications are set up and made to work in parallel.
[0064] In contrast, if parallel beams with a minimum spacing of d = 0.1m are used for through-beam transmission, L / d pairs, or 750 pairs, of LED light sources and photodetectors would be required. Even if 5 pairs of cascaded integrated transmitters and receivers are used, approximately 150 sets would still be needed to achieve effective coverage of the L = 75m area.
[0065] In summary, this invention, based on a microlens array and single-pixel imaging, provides a continuous, large-area coverage capability, avoiding the potential vulnerabilities caused by the limited number of beams in beam-based intrusion detectors, and effectively reducing the false negative rate of intrusion detection systems. Furthermore, due to its integrated transceiver design, it can be deployed at one end, making it particularly suitable for security and monitoring of unknown areas. Moreover, by employing a beam-shaped light spot and high-speed image post-processing, this invention can effectively reduce the number of intrusion detectors required for large-area detection tasks, saving on operating and maintenance costs.
[0066] In the description of this specification, references to terms such as "preferred embodiment," "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0067] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims
1. An intrusion detector based on a microlens array and single-pixel imaging, comprising a transmitter and a receiver, characterized in that: The transmitting end includes a central controller, a data image processor, a semiconductor laser, a phase modulator, a spatial light modulator, and a collimating lens; the receiving end includes a microlens array, a photon detector, a data image processor, and a servo alarm. The transmitter and receiver are integrated; a pair of microlens arrays and photon detectors are provided; the photon detectors are detectors with photon resolution capability, and the photon detectors are either Geiger mode avalanche photodiode detectors or superconducting single-photon detectors with superconducting mechanisms; the servo alarm includes an image input interface, an alarm feedback output interface, a siren drive output interface, a warning light drive output interface, an alarm message output interface, and a discrimination algorithm; The specific usage process is as follows: The central controller sends control signals to the semiconductor laser, causing it to emit laser light; at the same time, the data image processor sends modulation signals to the phase modulator, changing the modulation mode on the spatial light modulator. The optical signal modulated by the spatial light modulator is emitted through the collimating lens, reaches the area or object under test, and returns an echo signal. The echo signal returned from the measured area or the measured object is received by the microlens array, then detected by the photon detector, and the detection signal of the photon detector is received and processed by the data image processor. When the test signal emitted by the data image processor is a background test signal, a background image of the target scene is formed; when the test signal emitted by the data image processor is a real-time test signal, a real-time image of the target scene is formed; and the data image processor sends the background image and the real-time image of the target scene to the servo alarm through the image input interface, and the discrimination algorithm in the servo alarm determines whether there is an intrusion. If an intrusion is detected, the alarm feedback output interface will be used to send a signal to the central controller, which will then initiate an intrusion response strategy and begin target scene tracking and detection under intrusion conditions. Simultaneously, the alarm siren, alarm light, and alarm record text will be output through the siren drive output interface, the alarm light drive output interface, and the alarm text output interface, respectively. The image acquisition of the data image processor uses a single-pixel imaging algorithm.
2. The intrusion detector based on microlens array and single-pixel imaging according to claim 1, characterized in that: The laser emitted by the semiconductor laser is in the near-infrared band at 800nm.
3. An intrusion detector based on a microlens array and single-pixel imaging according to claim 2, characterized in that: The ratio of the background test signal to the real-time test signal is 1:5 to 1:
100.
4. An intrusion detector based on a microlens array and single-pixel imaging according to claim 3, characterized in that: The discrimination algorithm of the servo alarm is as follows: set a threshold ε, calculate the difference δ between the real-time imaging of the target scene and the background imaging of the target scene, and then calculate the function f(δ). If f(δ) > ε, it is judged that there is an intrusion; otherwise, it is judged that there is no intrusion.