Monitoring device, control method thereof and computer readable storage medium

Abstract

The invention provides a monitoring device and a control method thereof, and a computer readable storage medium, and relates to the technical field of monitoring, the monitoring device comprises a first PIR sensor, a second PIR sensor and a processor; a first detection area corresponding to the first PIR sensor and a second detection area corresponding to the second PIR sensor have an overlapping area; the processor is used for detecting whether a moving target enters an overlapping area within a preset duration based on first PIR data collected by the first PIR sensor and second PIR data collected by the second PIR sensor when it is determined that the moving target appears in the first detection area or the second detection area; if yes, according to the first PIR data and the second PIR data, determining whether the motion trail of the moving target meets an alarm triggering condition or not; and if yes, outputting alarm information. According to the technical scheme provided by the invention, the monitoring device can be effectively prevented from generating false alarms, and the detection accuracy of the monitoring device is improved.

Description

Technical Field

[0001] The present application relates to the field of monitoring technology, and in particular to a monitoring device and a control method thereof, and a computer-readable storage medium. Background Art

[0002] Pyroelectric Passive Infrared Ray (PIR) sensor is a sensor commonly used in the security field. It can detect infrared radiation emitted by objects and is particularly suitable for detecting the movement of warm objects such as humans or animals.

[0003] However, since the PIR sensor is easily disturbed by the fluctuation of the ambient temperature difference, the monitoring device will have many false alarms in actual applications, affecting the detection accuracy of the monitoring device. Summary of the invention

[0004] The present application provides a monitoring device and a control method thereof, and a computer-readable storage medium, which can effectively avoid false alarms from the monitoring device and improve the detection accuracy of the monitoring device.

[0005] In a first aspect, the present application provides a monitoring device, which includes a first PIR sensor, a second PIR sensor, and a processor; a first detection area corresponding to the first PIR sensor and a second detection area corresponding to the second PIR sensor have an overlapping area; the processor is used to:

[0006] Determining that a moving target appears in the first detection area or the second detection area;

[0007] Based on the first PIR data collected by the first PIR sensor and the second PIR data collected by the second PIR sensor, detecting whether the moving target enters the overlapping area within a preset time period;

[0008] When the moving target is detected to enter the overlapping area, determining whether the moving trajectory of the moving target meets the alarm triggering condition according to the first PIR data and the second PIR data;

[0009] If the motion trajectory meets the above alarm triggering conditions, the alarm information is output.

[0010] In some embodiments, the processor is specifically configured to:

[0011] Obtain the first PIR data and the second PIR data;

[0012] Down-sampling the first PIR data to obtain a first PIR signal, and down-sampling the second PIR data to obtain a second PIR signal;

[0013] When the first signal change rate of the first PIR signal at two adjacent sampling time points is greater than a preset change threshold, it is determined that a moving target appears in the first detection area;

[0014] When the second signal change rate of the second PIR signal at two adjacent sampling time points is greater than the change threshold, it is determined that a moving target appears in the second detection area.

[0015] In some embodiments, the processor is specifically configured to:

[0016] Determine a differential signal corresponding to the first PIR signal and the second PIR signal within a preset time length;

[0017] Determine whether the amplitude of the differential signal at the sampling time point t is less than a first threshold;

[0018] If the amplitude of the differential signal at the sampling time point t is less than the first threshold, determining whether a third signal change rate of the differential signal at the sampling time point t compared to the sampling time point t-1 is greater than a second threshold;

[0019] When the third signal change rate is greater than the second threshold, it is determined that the moving target enters the overlapping area.

[0020] In some embodiments, the processor is specifically configured to:

[0021] Determine whether the current detection environment is stable according to changes in the first PIR signal and the second PIR signal;

[0022] If the current detection environment is stable, the first threshold and / or the second threshold are updated.

[0023] In some embodiments, the processor is specifically configured to:

[0024] According to a preset sampling time window, respectively obtain at least one signal feature of the following items: a first PIR signal, a second PIR signal, a differential signal, a first signal change rate, a second signal change rate, and a third signal change rate; the above signal features include variance and peak-to-peak value;

[0025] The first threshold and / or the second threshold are updated according to the signal characteristics acquired in multiple sampling time windows.

[0026] In some embodiments, the processor is specifically configured to:

[0027] According to a preset sliding time window, an extreme value point in the first PIR signal and an extreme value point in the second PIR signal are obtained;

[0028] According to the extreme value point in the first PIR signal and the extreme value point in the second PIR signal, it is determined whether the motion trajectory of the mobile target meets the alarm triggering condition.

[0029] In some embodiments, the processor is specifically configured to:

[0030] Determine whether the moving target's trajectory meets the alarm triggering conditions in the following ways:

[0031] ;

[0032] ;

[0033] ;

[0034] in, and Respectively represent the number of minimum and maximum points in the first PIR signal, and Respectively represent the number of minimum and maximum points in the second PIR signal, Represents the maximum value of each minimum point in the first PIR signal, Represents the minimum value of each minimum point in the first PIR signal, Represents the maximum value of each minimum point in the second PIR signal, Represents the minimum value of each minimum point in the second PIR signal, Indicates the extreme point quantity difference threshold, represents the extreme difference threshold of the extreme point, =1, it is determined that the moving target's trajectory meets the alarm triggering condition. =0, it is determined that the motion trajectory of the moving target does not meet the alarm triggering conditions.

[0035] In some embodiments, the phase between the first PIR sensor and the second PIR sensor is adjustable.

[0036] In a second aspect, the present application provides a monitoring device control method, which is applied to a monitoring device, wherein the monitoring device includes a first PIR sensor, a second PIR sensor, and a processor; a first detection area corresponding to the first PIR sensor and a second detection area corresponding to the second PIR sensor have an overlapping area; the method includes:

[0037] Determining that a moving target appears in the first detection area or the second detection area;

[0038] Based on the first PIR data collected by the first PIR sensor and the second PIR data collected by the second PIR sensor, detecting whether the moving target enters the overlapping area within a preset time period;

[0039] When the moving target is detected to enter the overlapping area, determining whether the moving trajectory of the moving target meets the alarm triggering condition according to the first PIR data and the second PIR data;

[0040] If the motion trajectory meets the above alarm triggering conditions, the alarm information is output.

[0041] In a third aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the monitoring device control method provided in the second aspect.

[0042] The monitoring device and its control method, and computer-readable storage medium provided by the present application utilize the first PIR sensor and the second PIR sensor to jointly detect moving targets, which can significantly expand the detection field of view. At the same time, the edge monitoring area of ​​the single PIR sensor is used as a warning area. When the mobile target enters the warning area, the monitoring device can issue an early warning, thereby speeding up the capture speed. In addition, when it is determined that the mobile target enters the overlapping area, the authenticity of the mobile target can be further verified based on the motion trajectory of the mobile target, thereby effectively reducing false alarms and missed alarms and improving the detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0044] Figure 1 A schematic diagram of the structure of a monitoring device provided in an embodiment of the present application;

[0045] Figure 2 A schematic diagram of a monitoring area of ​​a monitoring device provided in an embodiment of the present application;

[0046] Figure 3 A control flow diagram of a monitoring device provided in an embodiment of the present application Figure 1 ;

[0047] Figure 4 A control flow diagram of a monitoring device provided in an embodiment of the present application Figure 2 ;

[0048] Figure 5 A schematic diagram of a feature extraction process provided in an embodiment of the present application;

[0049] Figure 6 A schematic diagram of a flow chart of a timed update judgment threshold provided in an embodiment of the present application;

[0050] Figure 7 This is a schematic diagram of the distribution of extreme value points under a PIR signal misalignment provided in an embodiment of the present application.

[0051] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope 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 DESCRIPTION

[0052] Here, each exemplary embodiment of the present application will be described in detail. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0053] In order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, "exemplary", "for example", etc. are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0054] In the embodiments of the present application, words such as "first" and "second" are used to distinguish the same or similar items with substantially the same functions and effects. For example, the first PIR signal and the second PIR signal are only used to distinguish different signals, and their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0055] In the embodiments of the present application, "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0056] The PIR sensor is a non-contact detection sensor based on the pyroelectric effect. Its working principle is to receive infrared radiation from human or animal through the internal pyroelectric element. When a person or animal moves within its detection range, the temperature difference between the person or animal and the surrounding environment will cause the infrared radiation field to change. This change will cause the above pyroelectric element to generate a weak electrical signal. After this signal is amplified and analyzed by the signal processor, once it exceeds the preset threshold, it can be determined that there is human or animal activity.

[0057] At present, in the field of video surveillance, PIR sensors are mainstream motion detection sensors with low power consumption and low cost, and have high detection capabilities. However, since PIR sensors are easily affected by ambient temperature differences, they are mostly used indoors. For outdoor monitoring scenarios, there will be more false alarms. For example, when the ambient temperature changes or is disturbed by other heat sources (such as direct sunlight, heating equipment, hot air currents, etc.), the PIR sensor may trigger an alarm by mistake. In addition, the activities of small animals and light fluctuations may also cause false alarms, affecting the detection accuracy.

[0058] For outdoor monitoring scenarios, in some solutions, a light and dark partition lens can be designed on the PIR sensor, and a delay mechanism can be added to reduce false alarms, but this solution will increase missed alarms and is not conducive to reducing power consumption. In other solutions, a temperature difference sensor can be used to monitor the ambient temperature difference and adjust the sensitivity of the PIR sensor according to the ambient temperature difference. Although this solution can reduce the probability of false alarms to a certain extent, it requires a high-precision ambient temperature detection capability, otherwise the ambient temperature error will still affect the detection effect.

[0059] In view of the above technical problems, a monitoring device is provided in an embodiment of the present application, which can use multiple PIR sensors to capture moving targets in indoor and outdoor scenes, and by adjusting the phase between the PIR sensors, the monitorable range of the field of view can be expanded. Compared with the detection scheme using a single PIR sensor, it can detect faster and review the detection results, thereby improving the detection accuracy.

[0060] The technical solution provided by the present application is described in detail below through specific embodiments. It should be noted that the following embodiments can exist independently or in combination with each other, and the same or similar contents will not be described repeatedly in different embodiments.

[0061] Reference Figure 1 , Figure 1 A schematic diagram of the structure of a monitoring device provided in an embodiment of the present application.

[0062] In some embodiments, the monitoring device 100 includes a first PIR sensor 101 , a second PIR sensor 102 , and a processor 103 .

[0063] The first PIR sensor 101 and the second PIR sensor 102 are used to detect infrared radiation from people or animals in their detection areas. Taking the first PIR sensor 101 as an example, when a biological body (such as a human or an animal) moves in its detection area, the first PIR sensor 101 can capture the changes in infrared radiation released by these biological bodies and convert them into electrical signals. The electrical signals are then sent to the processor 103 for further processing and analysis.

[0064] In some embodiments, the detection area of ​​the second PIR sensor 102 may partially overlap with the detection area of ​​the first PIR sensor 101 .

[0065] For example, refer to Figure 2 , Figure 2 A schematic diagram of a monitoring area of ​​a monitoring device provided in an embodiment of the present application.

[0066] exist Figure 2 In the present invention, the first detection area is the detection area corresponding to the first PIR sensor. When a moving target (such as a person or an animal) moves in the first detection area, the first PIR sensor can detect the change of infrared radiation released by the moving target.

[0067] The second detection area is the detection area corresponding to the second PIR sensor. When a moving target moves within the second detection area, the second PIR sensor can detect changes in infrared radiation released by the moving target.

[0068] There is an overlapping area between the first detection area and the second detection area. In this area, both the first PIR sensor and the second PIR sensor can detect the change of infrared radiation released by the moving target.

[0069] In some embodiments, the phase between the first PIR sensor and the second PIR sensor is adjustable.

[0070] In some implementations, the phase misalignment angle between the first PIR sensor and the second PIR sensor may be adjusted according to actual scenario requirements, thereby improving the robustness and adaptability of the monitoring device.

[0071] Reference Figure 3 , Figure 3 A control flow diagram of a monitoring device provided in an embodiment of the present application Figure 1 In some embodiments, the control process includes:

[0072] S301: Determine whether a moving target enters.

[0073] In some embodiments, the processor may acquire in real time first PIR data collected by the first PIR sensor and second PIR data collected by the second PIR sensor, determine whether a mobile target appears in the first detection area based on the first PIR data, and determine whether a mobile target appears in the second detection area based on the second PIR data.

[0074] When it is determined that a moving target appears in the first detection area or the second detection area, step S302 may be continued to be performed. Otherwise, the first PIR data and the second PIR data may be continued to be monitored.

[0075] S302: Acquire first PIR data collected by the first PIR sensor and second PIR data collected by the second PIR sensor.

[0076] In some embodiments, when it is determined that a mobile target appears in any of the first detection area or the second detection area, the latest PIR data of the first PIR sensor and the second PIR sensor can continue to be obtained to further verify the authenticity of the mobile target.

[0077] S303: Based on the first PIR data and the second PIR data, detect whether the moving target enters the overlapping area.

[0078] In some implementations, when it is determined that the moving target enters the overlapping area, S305 may be continued to be executed, otherwise S304 is executed.

[0079] S304, determining whether the preset time period has been exceeded.

[0080] In some embodiments, a preset time length may be pre-set to wait for the mobile target to enter the overlapping area or leave the detection area. If the alarm triggering condition is still not met after the preset time length (such as the mobile target has not entered the overlapping area, or has left the first detection area or the second detection area), the process returns to S301 and restarts monitoring the first PIR data and the second PIR data to determine whether a mobile target has entered. If the preset time length is not exceeded, the process returns to S302 to continue acquiring and updating PIR data to detect whether the mobile target has entered the overlapping area.

[0081] S305: Determine whether the motion trajectory of the moving target meets an alarm triggering condition according to the first PIR data and the second PIR data.

[0082] In some implementations, the motion trajectory of the moving target may be analyzed based on the first PIR data and the second PIR data. If the motion trajectory of the moving target meets the alarm triggering condition, then continue to execute S306; otherwise, return to execute S304.

[0083] S306: Output warning information.

[0084] In some implementations, when the motion trajectory of the moving target meets the alarm triggering condition, an alarm message is output. Optionally, the alarm message can be conveyed to the user or the monitoring system by sound, light, screen display, etc.

[0085] The present application provides a monitoring device that can achieve the following beneficial effects:

[0086] (1) By combining the PIR data collected by the first PIR sensor and the second PIR sensor, the detection field of view of the monitoring device can be significantly expanded, which helps to cover a wider monitoring area and improve the coverage of the monitoring device.

[0087] (2) The edge monitoring area of ​​a single PIR sensor is used as a warning area. When a moving target enters the warning area, the monitoring device can issue an early warning, thereby speeding up the capture speed.

[0088] (3) The left and right fields of view of the dual PIR sensors can be adjusted according to the actual scene requirements. By adjusting the phase misalignment angle between the first PIR sensor and the second PIR sensor, the detection range of the monitoring device can be optimized to better adapt to different monitoring environments.

[0089] (4) When it is determined that a moving target has entered the overlapping area, the authenticity of the moving target can be further verified based on the moving target's motion trajectory, thereby reducing false positives and false negatives and improving detection accuracy.

[0090] Reference Figure 4 , Figure 4 A control flow diagram of a monitoring device provided in an embodiment of the present application Figure 2 In some embodiments, the control process includes:

[0091] S401: Determine whether a moving target enters.

[0092] In some embodiments, the processor may acquire in real time first PIR data collected by the first PIR sensor and second PIR data collected by the second PIR sensor, determine whether a mobile target appears in the first detection area based on the first PIR data, and determine whether a mobile target appears in the second detection area based on the second PIR data.

[0093] When it is determined that a moving target appears in the first detection area or the second detection area, step S402 may be continued to be performed. Otherwise, the first PIR data and the second PIR data are continuously monitored to determine whether a moving target enters.

[0094] S402: down-sampling and differential processing are performed on the first PIR data collected by the first PIR sensor and the second PIR data collected by the second PIR sensor.

[0095] In some embodiments, the processor may obtain the first PIR data and the second PIR data; down-sample the first PIR data to obtain a first PIR signal, and down-sample the second PIR data to obtain a second PIR signal; when a first signal change rate of the first PIR signal at two adjacent sampling time points is greater than a preset change threshold, it is determined that a moving target appears in the first detection area; when a second signal change rate of the second PIR signal at two adjacent sampling time points is greater than a change threshold, it is determined that a moving target appears in the second detection area.

[0096] S403: Determine a judgment threshold.

[0097] In some embodiments, whether the current detection environment is stable can be determined based on changes in the first PIR signal and the second PIR signal; if the current detection environment is stable, the above judgment threshold is updated, otherwise the above judgment threshold is not updated.

[0098] In some embodiments, the judgment threshold may include a first threshold and a second threshold. The first threshold is a judgment threshold for detecting whether the mobile target enters the overlapping area, and the second threshold is a judgment threshold for detecting whether the first PIR signal and the second PIR signal are interference signals.

[0099] S404: Based on the above judgment threshold, detect whether the moving target enters the overlapping area.

[0100] In some implementations, when it is determined that the moving target enters the overlapping area, S406 may be continued to be executed, otherwise S405 is executed.

[0101] S405: Determine whether the preset time period has been exceeded.

[0102] In some embodiments, if the alarm triggering condition is not met after the preset time (such as the moving target does not enter the overlapping area), the process returns to S401 and restarts monitoring whether a moving target enters. If the preset time is not exceeded, the process returns to S402 and continues to acquire and update the first PIR data and the second PIR data.

[0103] S406. Extreme point statistics.

[0104] In some implementations, the extreme value changes of the first PIR signal and the second PIR signal within a fixed time window may be statistically analyzed to determine the movement trajectory of the moving target transversely crossing the overlapping area.

[0105] S407: Determine whether the motion trajectory of the moving target satisfies an alarm triggering condition.

[0106] It is understandable that if the phase of the first PIR sensor and the second PIR sensor is misaligned by 1 / 2 (or 1 / 4) cycle, when the mobile target passes through the overlapping area, the phase difference between the extreme points of the first PIR signal and the second PIR signal is 1 / 2 (or 1 / 4) cycle. In some embodiments, the logic of the alternating extreme points of the first PIR signal and the second PIR signal can be used to determine whether the motion trajectory of the mobile target is continuous. If it is not continuous, it means that there is a large noise interference in the field of view, and the motion trajectory of the mobile target does not meet the alarm triggering condition, and the false alarm information needs to be filtered.

[0107] In some implementations, if the motion trajectory of the moving target meets the alarm triggering condition, then continue to execute S408; otherwise, return to execute S405.

[0108] S408: Output warning information.

[0109] In order to better understand the embodiments of the present application, the above steps S402 to S407 are described in detail below.

[0110] In step S402, it can be understood that when the mobile target enters the first detection area or the second detection area, there is a temperature difference ∆T between the mobile target (heat source) and the ambient temperature, and the radiation generated by the mobile target will be absorbed by the first PIR sensor or the second PIR sensor, thereby generating movement of sufficient charge, causing the detection value of the first PIR sensor or the second PIR sensor to change significantly, and when the mobile target moves, it can be observed in the time series that the detection value of the first PIR sensor or the second PIR sensor shows a trend of rapid increase or decrease.

[0111] In some embodiments, the first PIR sensor and the second PIR sensor may be equipped with a lens system, and the lens may be divided into a plurality of light and dark partitions. When a moving target passes through these light and dark partitions of the lens, each partition may have different absorption and focusing effects on radiation, thereby causing the detection values ​​of the first PIR sensor and / or the second PIR sensor to fluctuate significantly. This fluctuation pattern not only provides evidence of the existence of a moving target, but can also be used to further analyze the target's motion trajectory and speed.

[0112] In order to quickly and effectively identify the fluctuation of the above detection values, the single-channel PIR signal can be differentially processed to extract the fluctuation characteristics, so that the monitoring device can enter the early warning detection mode in advance and improve the real-time performance of the capture.

[0113] For example, assuming that the first PIR data corresponding to the first detection area is , the second PIR data corresponding to the second detection area is When the moving target enters the edge of the first detection area or the second detection area, the monitoring device will be awakened and the first PIR data With the second PIR data Perform down-sampling to obtain the first PIR signal arranged horizontally With the second PIR signal , the relationship is as follows:

[0114] ;

[0115] Among them, i represents the i-th PIR signal, is the observation frequency of the effective waveform, is the system timing sampling time, is the sampling function.

[0116] In some implementations, the speed and time at which the moving target enters the first detection area or the second detection area may be obtained by performing differential processing on the first PIR signal or the second PIR signal.

[0117] For example:

[0118] ;

[0119] in, It indicates the result of differential processing of PIR signal corresponding to channel i at time t. When the value is greater than the set change threshold, it means that the moving target crosses the detection area of ​​the i-th PIR sensor, and the monitoring device can enter the early warning detection stage at this time.

[0120] In step S404, the differential signal corresponding to the first PIR signal and the second PIR signal within a preset time period can be determined. ; Determine the differential signal The amplitude at sampling time t Is it less than the first threshold L? is less than L, then the above differential signal is determined The third signal change rate at sampling time point t compared to sampling time point t-1 Is it greater than the second threshold? ;when Greater than , it is determined that the moving target enters the above-mentioned overlapping area.

[0121] Specifically, when When the following formula is satisfied, it is determined that the moving target enters the above overlapping area:

[0122] ;

[0123] It can be understood that, since the viewing angle of the monitoring device is substantially consistent with the overlapping area, when the moving target enters the overlapping area from the edge of the first detection area or the second detection area, the differential signal Will shrink dramatically.

[0124] In step S403, at least one of the following signal characteristics may be obtained according to a preset sampling time window: the first PIR signal , Second PIR signal , differential signal , the first signal change rate , the second signal change rate , the third signal change rate The above signal characteristics include variance and peak-to-peak value. Update the first threshold value according to the signal characteristics obtained in multiple sampling time windows and / or a second threshold .

[0125] For example, when a moving target enters the first detection area or the second detection area and triggers an early warning, the signal characteristics in the current time domain can be obtained: signal change rate variance and , signal variance and , signal change rate peak-to-peak and And the peak-to-peak value of the signal and .

[0126] In order to extract the feature differences before and after the trigger, the embodiment of the present application adopts a timed sampling method, the main purpose of which is to record the environmental features after the monitoring device is awakened, and update the and .

[0127] Reference Figure 5 , Figure 5 A schematic diagram of a feature extraction process provided in an embodiment of the present application.

[0128] In some embodiments, the variance and peak-to-peak value of the source data and data change rate in different time series can be obtained by periodically sampling the cache (collecting N data) in multiple time periods. Based on the variance and peak-to-peak value of the M-segment queue, the optimal variance and peak-to-peak value for an interference-free environment are calculated, and the peak-to-peak value is used as the basis for updating the threshold.

[0129] Exemplarily, the first threshold With the second threshold The following formula can be satisfied:

[0130] ;

[0131] ;

[0132] ;

[0133] ;

[0134] in, It is a characteristic value queue of the targetless environment with regular sampling statistics (the elements are the variance and peak-to-peak value of the statistical time period). For The result after sorting the variance elements in the first row of the queue in ascending order, is the sorting algorithm, Represents the threshold amplification factor.

[0135] In some implementations, when the maximum variance in any of the above queues is much larger than the mean variance of the current queue, the maximum variance may be deleted, otherwise it is used as a reference for updating the threshold.

[0136] Reference Figure 6 , Figure 6 A schematic diagram of a flow chart for periodically updating a judgment threshold value provided in an embodiment of the present application.

[0137] In some implementations, the process of periodically updating the judgment threshold includes:

[0138] S601: Determine timer interruption.

[0139] In some implementations, a timer may be pre-set, and the timer may periodically trigger an interruption. The timer may ensure that the above-mentioned process of regularly updating the judgment threshold value may be executed regularly.

[0140] S602: PIR signal sampling and buffering.

[0141] In some implementations, the PIR signal sampling buffer includes a first PIR signal sampling buffer and a second PIR signal sampling buffer.

[0142] In some implementations, after the timer interrupt is triggered, the first PIR signal and the second PIR signal may be collected and cached.

[0143] S603: Determine whether the number of sampling points is greater than or equal to a preset number threshold.

[0144] In some implementations, it may be checked whether the number of cached PIR signal sampling points has reached a preset number threshold. If the number of sampling points is sufficient, the next step S604 is continued; otherwise, the process returns to S602 to continue collecting and caching more PIR signals.

[0145] S604: Determine whether to trigger a detection warning.

[0146] In some embodiments, after the number of sampling points reaches a preset number threshold, the sampling points may be analyzed to determine whether a detection warning is triggered. If a detection warning is triggered, the next step S605 is continued; otherwise, the process returns to S602 to continue collecting and caching PIR signals.

[0147] S605: Determine signal characteristics.

[0148] In some implementations, after determining that a detection warning is triggered, the cached PIR signal sampling points may be further analyzed to determine the signal characteristics thereof.

[0149] S606: Update the judgment threshold.

[0150] In some embodiments, based on the signal characteristics obtained through analysis, the above-mentioned judgment threshold can be updated to improve the adaptability and accuracy of the monitoring device, so that it can better cope with target detection tasks in different environments and conditions.

[0151] In some embodiments, in a non-interference environment, the above-mentioned signal features can be directly extracted as a reference for determining threshold updates; in an interference environment, the above-mentioned queue under the alarm environment can be screened until the next update of valid signal features, and then included in the statistics and update links.

[0152] In some embodiments, for step S406, the extreme points in the first PIR signal and the extreme points in the second PIR signal can be obtained according to a preset sliding time window; based on the extreme points in the first PIR signal and the extreme points in the second PIR signal, it is determined whether the motion trajectory of the mobile target meets the alarm triggering conditions.

[0153] For example, when it is determined that the mobile target enters the overlapping area, the current first PIR signal and the second PIR signal can be sampled and counted to extract the sliding time window The minimum point in the data and maximum point , cache the current extreme point data.

[0154] In some implementations, when it is determined that the moving target enters the overlapping area, the timestamp count and the magnitude of the extreme value point are recorded, and the relevant formula is as follows:

[0155] ;

[0156] ;

[0157] in, is the timestamp subscript of the minimum point, is the minimum value size in the sliding window, A sequence is source data cached within a sliding time window.

[0158] ;

[0159] ;

[0160] in, is the timestamp subscript of the maximum point, is the maximum value in the sliding time window, A sequence is source data cached within a sliding time window.

[0161] For example, refer to Figure 7 , Figure 7 This is a schematic diagram of the distribution of extreme value points under a PIR signal misalignment provided in an embodiment of the present application.

[0162] Since the lateral field of view of the PIR sensor lens is adjustable, by adjusting the spacing between the first PIR sensor and the second PIR sensor lens partitions, the light and dark partitions of the PIR field of view can be misaligned, thereby generating more partitions. When a moving target passes through these partitions, the PIR signal will rise or fall, generating multiple peaks and troughs. Through continuity (such as Figure 7 By comparing the peaks and troughs, it can be determined whether the current moving target's motion trajectory meets the alarm triggering conditions.

[0163] from Figure 7 It can be seen that after the phase shift of the first PIR signal and the second PIR signal, the moving target is in the dark area compared to the first PIR sensor and in the bright area compared to the second PIR sensor at the same position. The motion trajectory of a single moving target has an obvious lag in the first PIR signal and the second PIR signal. According to the extreme point information of the first PIR signal and the second PIR signal when the moving target crosses the bright and dark areas, two curves can be fitted.

[0164] If the two curves have a high degree of overlap, it means that the moving target actually exists; if the overlap is low and the number of extreme points between the first PIR signal and the second PIR signal is significantly different, it means that there are interference sources at multiple points in the environment, which can be regarded as a false alarm.

[0165] Through the above method, the interference of environmental factors such as leaf swinging can be effectively filtered out, and the excitation signal generated by the repeated switching between the shadow side and the illuminated side of the leaves in a single partition can be eliminated.

[0166] In some embodiments, due to the uncertainty of outdoor environment and moving targets, the maximum value sequence and the minimum value sequence will not be clearly distinguished in terms of value, and due to the continuity of the trajectory, the number of extreme values ​​should be close. and When the number difference is large, it can be considered that the current ambient temperature change causes the amplitude to continue to increase. At the same time, a certain number of extreme points should be met to indicate that there are moving targets in the detection environment, thereby filtering the excitation signals generated by factors such as environmental disturbances.

[0167] The following are the prerequisites for extreme value continuity judgment:

[0168] ;

[0169] In the above formula, Represents a function that counts the number of sequence elements. is a minimum value sequence, is a maximum value sequence, To detect the upper limit of the number of effective extreme points, It is the lower limit of the difference in the number of extreme points for judging the symmetry of the motion trajectory.

[0170] In some embodiments of the present application, since the radiation amount of the same moving target to the above-mentioned overlapping area is basically consistent, and the corresponding extreme point curves have the same trend in the overlapping part and the phases are staggered, the motion trajectory equation of the target can be obtained by comparing the number and size of the extreme points of the PIR sensors distributed on the left and right, thereby screening out the influence of PIR false alarm data on the results.

[0171] Exemplarily, whether the motion trajectory of the moving target meets the alarm triggering condition may be determined in the following manner:

[0172] ;

[0173] ;

[0174] ;

[0175] in, and Respectively represent the number of minimum and maximum points in the first PIR signal, and Respectively represent the number of minimum and maximum points in the second PIR signal, Represents the maximum value of each minimum point in the first PIR signal, Represents the minimum value of each minimum point in the first PIR signal, Represents the maximum value of each minimum point in the second PIR signal, Represents the minimum value of each minimum point in the second PIR signal, Indicates the extreme point quantity difference threshold, The extreme difference threshold that represents extreme points.

[0176] R is the PIR alarm output result, is the result of judging the number of extreme points, It is the result of judging the extreme value.

[0177] In some embodiments, =1, it is determined that the moving target's trajectory meets the alarm triggering condition. =0, it is determined that the motion trajectory of the moving target does not meet the alarm triggering conditions.

[0178] In some embodiments, when the number of extreme points of the two PIR signals is close, it means that the target trajectories overlap and the mobile target detection is effective; when the number of extreme points of the two PIR signals differs greatly, it means that the mobile target has only entered the warning boundary of a single PIR sensor, or there is environmental noise (such as wind blowing leaves) interference in the detection area, and direct filtering is performed.

[0179] In some embodiments, when it is determined that the motion trajectory of the mobile target does not meet the alarm triggering conditions, an alarm is triggered. Otherwise, a timeout mechanism is entered to wait for judgment. Detection continues within the time range, and detection is stopped outside the time range, waiting for the next detection of the mobile target entering before re-warning and review.

[0180] The monitoring device provided by the present application utilizes a combination of multiple PIR sensors. By adjusting the phases between the PIR sensors, the monitorable range of the field of view can be expanded. Compared with a single PIR sensor, it can detect and conduct misjudgment review faster, thereby improving the detection accuracy. In the use scenario of low-power devices, physical partition changes are achieved through optical structural parts, and differential feature extraction and target trajectory tracking of misaligned PIR signals are performed through software algorithms, which can ensure both real-time detection and snapshot accuracy.

[0181] In addition, the monitoring device provided by the present application can capture fast-moving targets in real time by extracting the differential characteristics of the signal, and has a higher real-time detection and capture capability for fast-moving targets; by recording the maximum and minimum points before and after the moving target crosses multiple partitions, the position of the current moving target in the PIR field of view can be determined by the number and distribution of extreme points; through the staggered distribution of dual PIR sensors, the signal change characteristics in the short-term time series can be detected, and the lateral crossing trajectory of the moving target can be tracked according to the alternating change characteristics of the staggered signal, and the authenticity of the target can be re-judged through the trajectory continuity, thereby improving the detection accuracy of regional crossing.

[0182] In some embodiments of the present application, a monitoring device control method is further provided, which can be applied to a monitoring device, wherein the monitoring device includes a first PIR sensor, a second PIR sensor, and a processor; a first detection area corresponding to the first PIR sensor and a second detection area corresponding to the second PIR sensor have an overlapping area; the above monitoring device control method includes:

[0183] Determining that a moving target appears in the first detection area or the second detection area;

[0184] Based on the first PIR data collected by the first PIR sensor and the second PIR data collected by the second PIR sensor, detecting whether the moving target enters the overlapping area within a preset time period;

[0185] When the moving target is detected to enter the overlapping area, determining whether the moving trajectory of the moving target meets the alarm triggering condition according to the first PIR data and the second PIR data;

[0186] If the motion trajectory meets the above alarm triggering conditions, the alarm information is output.

[0187] The monitoring device control method provided in the present application utilizes the first PIR sensor and the second PIR sensor to jointly detect the moving target, which can significantly expand the detection field of view. At the same time, the edge monitoring area of ​​the single PIR sensor is used as the early warning area. When the mobile target enters the early warning area, the monitoring device can issue an early warning, thereby speeding up the capture speed. In addition, when it is determined that the mobile target enters the overlapping area, the authenticity of the mobile target can be further verified based on the motion trajectory of the mobile target, thereby effectively reducing false alarms and missed alarms and improving the detection accuracy.

[0188] In some embodiments, the above method further comprises:

[0189] Acquire the first PIR data and the second PIR data;

[0190] Down-sampling the first PIR data to obtain a first PIR signal, and down-sampling the second PIR data to obtain a second PIR signal;

[0191] When a first signal change rate of the first PIR signal at two adjacent sampling time points is greater than a preset change threshold, it is determined that a moving target appears in the first detection area;

[0192] When a second signal change rate of the second PIR signal at two adjacent sampling time points is greater than the change threshold, it is determined that a moving target appears in the second detection area.

[0193] In some embodiments, the above-mentioned detecting whether the moving target enters the overlapping area within a preset time period based on the first PIR data collected by the first PIR sensor and the second PIR data collected by the second PIR sensor includes:

[0194] Determine a differential signal corresponding to the first PIR signal and the second PIR signal within a preset time length;

[0195] Determine whether the amplitude of the differential signal at the sampling time point t is less than a first threshold;

[0196] If the amplitude of the differential signal at the sampling time point t is less than the first threshold, determining whether a third signal change rate of the differential signal at the sampling time point t compared to the sampling time point t-1 is greater than a second threshold;

[0197] When the third signal change rate is greater than the second threshold, it is determined that the moving object enters the overlapping area.

[0198] In some embodiments, the above method further comprises:

[0199] Determine whether the current detection environment is stable according to changes in the first PIR signal and the second PIR signal;

[0200] If the current detection environment is stable, the first threshold and / or the second threshold is updated.

[0201] In some embodiments, updating the first threshold and / or the second threshold includes:

[0202] According to a preset sampling time window, respectively obtain at least one signal feature of the following items: a first PIR signal, a second PIR signal, a differential signal, a first signal change rate, a second signal change rate, and a third signal change rate; the above signal features include variance and peak-to-peak value;

[0203] The first threshold and / or the second threshold are updated according to the signal characteristics acquired in the multiple sampling time windows.

[0204] In some embodiments, determining whether the motion trajectory of the mobile target meets the alarm triggering condition according to the first PIR data and the second PIR data includes:

[0205] According to a preset sliding time window, an extreme value point in the first PIR signal and an extreme value point in the second PIR signal are obtained;

[0206] According to the extreme value point in the first PIR signal and the extreme value point in the second PIR signal, it is determined whether the motion trajectory of the mobile target meets the alarm triggering condition.

[0207] In some embodiments, the above-mentioned determining whether the motion trajectory of the mobile target meets the alarm triggering condition according to the extreme value point in the first PIR signal and the extreme value point in the second PIR signal includes:

[0208] Determine whether the moving target's trajectory meets the alarm triggering conditions in the following ways:

[0209] ;

[0210] ;

[0211] ;

[0212] in, and Respectively represent the number of minimum and maximum points in the first PIR signal, and Respectively represent the number of minimum and maximum points in the second PIR signal, Represents the maximum value of each minimum point in the first PIR signal, Represents the minimum value of each minimum point in the first PIR signal, Represents the maximum value of each minimum point in the second PIR signal, Represents the minimum value of each minimum point in the second PIR signal, Indicates the extreme point quantity difference threshold, represents the extreme difference threshold of the extreme point, =1, it is determined that the moving target's trajectory meets the alarm triggering condition. =0, it is determined that the motion trajectory of the moving target does not meet the alarm triggering conditions.

[0213] The present application also provides a computer-readable storage medium, which stores a computer program (also referred to as code or instruction). When the computer program is executed, the monitoring device control method provided in the above-mentioned embodiment can be implemented.

[0214] The present application also provides a computer program product, which includes: a computer program (also referred to as code, or instruction). When the computer program is executed, the monitoring device control method provided in the above-mentioned embodiment can be implemented.

[0215] It is understandable that the division of each unit or module in the above-mentioned monitoring device is only a division of logical functions. Each function may correspond to a unit / functional module, or two or more functions may be integrated into one unit / functional module. In actual implementation, all or part of the units / modules may be integrated into one physical entity, or they may be distributed in different physical entities. In addition, the above-mentioned functional modules may be implemented in the form of hardware, software, or a combination of hardware and software, depending on the actual situation. Whether a function is executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0216] In the above embodiments, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The steps of the method provided in the present application may be directly embodied as being executed by a hardware processor, or may be executed by a combination of hardware and software modules in the processor.

[0217] The functional units in the various embodiments of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0218] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can essentially or in other words, the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0219] Finally, it should be noted that this application is intended to cover any variation, use or adaptation of this application, which follows the general principles of this application and includes common knowledge or customary technical means in the technical field that are not applied for in this application, is not limited to the precise structure described above and shown in the drawings, and can be modified and changed in various ways without departing from the scope thereof. The scope of this application is limited only by the appended claims.

Claims

1. A monitoring device, characterized in that: The monitoring device includes a first pyroelectric infrared (PIR) sensor, a second PIR sensor, and a processor; a first detection area corresponding to the first PIR sensor and a second detection area corresponding to the second PIR sensor have an overlapping area; the processor is used to: Determine that a moving target appears in the first detection area or the second detection area; Based on the first PIR data collected by the first PIR sensor and the second PIR data collected by the second PIR sensor, detecting whether the moving target enters the overlapping area within a preset time period; When it is detected that the mobile target enters the overlapping area, determining whether the motion trajectory of the mobile target meets the alarm triggering condition according to the first PIR data and the second PIR data; If the motion trajectory meets the alarm triggering condition, the alarm information is output.

2. The monitoring device according to claim 1, characterized in that: The processor is further configured to: Acquire the first PIR data and the second PIR data; Down-sampling the first PIR data to obtain a first PIR signal, and down-sampling the second PIR data to obtain a second PIR signal; When a first signal change rate of the first PIR signal at two adjacent sampling time points is greater than a preset change threshold, it is determined that a moving target appears in the first detection area; When a second signal change rate of the second PIR signal at two adjacent sampling time points is greater than the change threshold, it is determined that a moving target appears in the second detection area.

3. The monitoring device according to claim 2, characterized in that: The processor is specifically used for: Determine a differential signal corresponding to the first PIR signal and the second PIR signal within the preset time length; Determining whether the amplitude of the differential signal at the sampling time point t is less than a first threshold; If the amplitude of the differential signal at the sampling time point t is less than the first threshold, determining whether a third signal change rate of the differential signal at the sampling time point t compared to the sampling time point t-1 is greater than a second threshold; When the third signal change rate is greater than the second threshold, it is determined that the moving object enters the overlapping area.

4. The monitoring device according to claim 3, characterized in that: The processor is further configured to: Determining whether the current detection environment is stable according to changes in the first PIR signal and the second PIR signal; If the current detection environment is stable, the first threshold and / or the second threshold are updated.

5. The monitoring device according to claim 4, characterized in that: The processor is specifically used for: According to a preset sampling time window, respectively obtain at least one signal feature of the following items: the first PIR signal, the second PIR signal, the differential signal, the first signal change rate, the second signal change rate, and the third signal change rate; the signal features include variance and peak-to-peak value; The first threshold and / or the second threshold are updated according to the signal characteristics acquired in multiple sampling time windows.

6. The monitoring device according to claim 2, characterized in that: The processor is specifically used for: According to a preset sliding time window, acquiring an extreme value point in the first PIR signal and an extreme value point in the second PIR signal; According to the extreme value point in the first PIR signal and the extreme value point in the second PIR signal, it is determined whether the motion trajectory of the mobile target meets the alarm triggering condition.

7. The monitoring device according to claim 6, characterized in that: The processor is specifically used for: Determine whether the motion trajectory of the moving target meets the alarm triggering condition in the following manner: ； ； ； in, and respectively represent the number of minimum and maximum points in the first PIR signal, and Respectively represent the number of minimum and maximum points in the second PIR signal, represents the maximum value of each minimum point in the first PIR signal, represents the minimum value of each minimum point in the first PIR signal, represents the maximum value of each minimum point in the second PIR signal, represents the minimum value of each minimum point in the second PIR signal, Indicates the extreme point quantity difference threshold, represents the extreme difference threshold of the extreme point, =1, it is determined that the motion trajectory of the moving target meets the alarm triggering condition, =0, it is determined that the motion trajectory of the moving target does not satisfy the alarm triggering condition.

8. The monitoring device according to any one of claims 1 to 7, characterized in that: The phase between the first PIR sensor and the second PIR sensor is adjustable.

9. A monitoring device control method, characterized in that: Applied to a monitoring device, the monitoring device includes a first PIR sensor, a second PIR sensor and a processor; a first detection area corresponding to the first PIR sensor and a second detection area corresponding to the second PIR sensor have an overlapping area; the method includes: Determine that a moving target appears in the first detection area or the second detection area; Based on the first PIR data collected by the first PIR sensor and the second PIR data collected by the second PIR sensor, detecting whether the moving target enters the overlapping area within a preset time period; When it is detected that the mobile target enters the overlapping area, determining whether the motion trajectory of the mobile target meets the alarm triggering condition according to the first PIR data and the second PIR data; If the motion trajectory meets the alarm triggering condition, the alarm information is output.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the monitoring device control method according to claim 9 is implemented.

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