Human motion recognition detection method and PIR detector

Abstract

The application discloses a human motion recognition and detection method, which comprises the following steps: collecting and amplifying a thermal release infrared signal at a first sampling frequency to obtain a thermal release infrared amplified signal; recording the thermal release infrared amplified signal as a sample; collecting and saving all samples in a first sampling period, and judging whether a detection target is biological motion according to the samples; if the detection target is biological motion, recording all saved samples as biological motion samples; obtaining a peak value of the biological motion samples in a first half of the sampling period, and performing voltage analysis on the peak value of the biological motion samples; and if the peak value of the biological motion samples is greater than or equal to a second voltage threshold, judging that the detection target is human motion. A PIR detector is also provided. The above method can exclude the false triggering of domestic pets in gentle motion, and avoid misjudgment in the above case.

Description

Technical Field

[0001] This invention relates to the field of motion recognition and detection technology, and in particular to a human motion recognition and detection method and a PIR detector. Background Technology

[0002] PIR sensors use photoelectric technology to passively detect the infrared radiation emitted by objects, calculating the temperature of each point on the object's surface and displaying different temperatures with different colors, thus converting them into images and graphics that can be distinguished by human vision. The PIR sensor transmits the signal received by its sensing element to a signal processing circuit for amplification, filtering, and analysis to determine if human movement is occurring. If human movement is detected, it generates an output signal, typically a voltage pulse or digital signal, which can be used to trigger alarm systems, lighting equipment, or other control devices. PIR sensors can overcome the limitations of human vision, detecting objects in complete darkness, even in the presence of smoke or dust, and without requiring a light source, making them suitable for all-weather use. Due to its advantages such as good concealment, strong anti-interference capabilities, strong target recognition ability, and all-weather operation, infrared thermal imaging is playing an increasingly important role in both military and civilian fields.

[0003] While infrared signals can be used to detect objects, many households keep small or large pets such as cats and dogs in addition to humans. When pets walk or jump, the infrared signals they emit can be captured by PIR sensors, and even the movement of non-living things that generate heat can trigger false alarms. This is especially problematic in home security systems, where pet activity can cause frequent alarms, compromising the accuracy of infrared detection.

[0004] The purpose of this application is to provide at least one human motion recognition and detection method and its PIR detector that solves the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a human motion recognition and detection method and a PIR detector to overcome the shortcomings of the above-mentioned technologies.

[0006] The present invention provides a human motion recognition and detection method, comprising the following steps: Within the area to be detected, the pyroelectric infrared signal of the target is acquired in real time at the first sampling frequency, and the acquired signal is amplified to obtain the real-time pyroelectric infrared amplified signal. Based on the pyroelectric infrared amplified signal, the pyroelectric infrared amplified signal is recorded as a sample; Collect and save all the samples within the first sampling period, and determine whether the detection target is biological movement based on the samples; If the target of the detection is determined to be biological motion, all the saved samples will be recorded as biological motion samples; The peak value of the biological motion sample in the first half of the sampling period is obtained, and the voltage of the peak value of the biological motion sample is analyzed. If it is determined that the peak value of the biological motion sample is greater than or equal to the second voltage threshold, then the detection target is determined to be human motion.

[0007] Preferably, the voltage analysis of the peak value of the biological motion sample further includes the following steps: If the peak value of the biological motion sample is determined to be less than or equal to the third voltage threshold, then the detection target is determined to be human motion.

[0008] Preferably, the step of obtaining the peak value of the biological motion sample in the first half of the sampling period and performing voltage analysis on the peak value of the biological motion sample includes the following steps: The peak value of the biological motion sample in the first half of the sampling period was obtained by using the peak detection method. The peak value of the biological motion sample is compared with the second voltage threshold. When it is determined that the peak value of the biological motion sample is greater than or equal to the second voltage threshold, it is preliminarily determined that the detection target is human motion. The peak value of the biological motion sample is then compared with the third voltage threshold. If the peak value of the biological motion sample is less than or equal to the third voltage threshold, the detection target is determined to be human motion.

[0009] Preferably, before obtaining the peak value of the biological motion sample in the first half of the sampling period, the following steps are also included: Voltage analysis is performed on the voltage values ​​of the biological motion samples in the first half of the sampling period, specifically including: Determine whether there is a biological motion sample whose voltage value is greater than or equal to a second voltage threshold in the first half of the sampling period. If the voltage value of the biological motion sample is greater than or equal to the second voltage threshold, then the biological motion sample is recorded as a valid signal. Determine whether the number of valid signals is greater than a set proportion of the total number of biological motion samples in the first half of the sampling period. If the number of valid signals is greater than the set proportion, then obtain the peak value of the biological motion samples in the first half of the sampling period.

[0010] Preferably, the process of collecting and storing all samples within the first sampling period, and determining whether the detected target is a biological movement based on the samples, includes the following steps: A first number of samples are collected and saved at a second sampling frequency. Then, the voltage values ​​of all samples in the first half of the first sampling period are averaged and voltage analysis is performed. If the average voltage value is greater than or equal to a first voltage threshold, the detection target is determined to be biological motion. Wherein, the first sampling period is equal to the product of the second sampling frequency and the first quantity.

[0011] Preferably, the method involves collecting and storing a first number of samples at a second sampling frequency, then averaging the voltage values ​​of all samples in the first half of the first sampling period and performing voltage analysis. If the average voltage value is greater than or equal to a first voltage threshold, the detection target is determined to be biological motion. This includes the following steps: The pyroelectric infrared amplified signal continues to be sampled at the second sampling frequency; Determine whether the number of samples acquired at the second sampling frequency reaches the first number. When it is determined that the number of acquired samples reaches the first number, save the first number of samples acquired at the second sampling frequency. Then, use the averaging method to calculate the average voltage of all samples in the first half of the first sampling period. The average voltage is compared with the first voltage threshold. If the average voltage is greater than or equal to the first voltage threshold, the detection target is determined to be biological motion.

[0012] Preferably, the step of recording the pyroelectric infrared amplified signal as a sample based on the pyroelectric infrared amplified signal includes the following steps: Voltage analysis is performed on the collected pyroelectric infrared amplified signal. If the voltage value of the pyroelectric infrared amplified signal is greater than or equal to a first voltage threshold, it is preliminarily determined that the detected target is biological motion, and the pyroelectric infrared amplified signal after the first voltage threshold is recorded as a sample.

[0013] Preferably, the acquisition of the pyroelectric infrared signal of the target is achieved using a PIR sensor combined with a Fresnel lens.

[0014] Preferably, the PIR sensor is electrically connected to the signal amplification and processing unit to amplify the collected pyroelectric infrared signal in multiple stages to obtain a real-time pyroelectric infrared amplified signal. The signal amplification and processing unit includes an interface electrically connected to a PIR sensor and a PIR signal terminal electrically connected to a control unit. An operational amplifier circuit and a secondary operational amplifier circuit are sequentially connected between the interface and the PIR signal terminal. The output terminal of the operational amplifier circuit, the output terminal of the secondary operational amplifier circuit, and the interface are respectively connected to a channel analog switch electrically connected to the control unit.

[0015] Preferably, the step of recording all saved samples as biomovement samples includes the following steps: The slope of the samples in the first half of the first sampling period is analyzed between different sampling time points to determine whether the slope change of the sample is from an upward trend to a downward trend. If the slope change of the sample is from an upward trend to a downward trend, then all the saved samples are recorded as biological motion samples.

[0016] The present invention also provides a PIR detector that employs the aforementioned human motion recognition and detection method.

[0017] Preferably, the PIR detector includes: Fresnel lenses are used for zonal focusing to achieve zonal identification of targets within the area to be detected; A PIR sensor is located at the rear end of a Fresnel lens to receive infrared radiation focused by the Fresnel lens to obtain a pyroelectric infrared signal. The signal amplification and processing unit is electrically connected to the PIR sensor and is used to amplify and process the pyroelectric infrared signal in multiple stages to obtain the real-time pyroelectric infrared amplified signal. The first voltage analysis unit is used to perform voltage analysis on the pyroelectric infrared amplified signal in the aforementioned detection method; The storage unit is used to implement the function of saving the first number of samples collected at the second sampling frequency in the aforementioned detection method; The second voltage analysis unit is used to perform voltage analysis by averaging the voltage values ​​of all samples in the first half of the first sampling period in the aforementioned detection method. The slope analysis unit is used to implement the function of analyzing the slope of the sample in the first half of the first sampling period between different sampling time points in the aforementioned detection method. The third voltage analysis unit is used to determine whether the voltage value of a biological motion sample is greater than or equal to the second voltage threshold in the first half of the sampling cycle of the aforementioned detection method. The effective signal quantity analysis unit is used to realize the function of judging the quantity of the effective signals in the aforementioned detection method; The fourth voltage analysis unit is used to perform voltage analysis on the peak value of the biological motion sample in the aforementioned detection method; The control unit is used to control the working status of the first voltage analysis unit, the storage unit, the second voltage analysis unit, the slope analysis unit, the third voltage analysis unit, the effective signal quantity analysis unit, and the fourth voltage analysis unit respectively according to the aforementioned detection method.

[0018] The technical advantage of this invention is that after amplifying the pyroelectric infrared signal, the biological motion sample in the first half of the first sampling period is compared with the second voltage threshold to determine whether the target in the detection area is human motion. This can eliminate false triggering situations such as pets moving slowly, thus avoiding misjudgment in the above situations. It can accurately detect human motion with high detection accuracy.

[0019] By comparing biological motion samples with a third voltage threshold, false triggering caused by large domestic pets jumping is eliminated. By comparing the number of valid signals with a set ratio of the total number of biological motion samples in the first half of the sampling period, false triggering caused by non-continuous movement in non-human motion is eliminated. By analyzing the slope of the samples between different sampling time points, false triggering caused by sensor failure is eliminated. By comparing the average voltage of the samples with a first voltage threshold, false triggering caused by jumping movements of small domestic pets and random infrared signal interference from external infrared light sources is eliminated. By comparing the voltage value of the samples with the first voltage threshold, the accuracy and validity of the samples are ensured. The above methods are applicable to usage scenarios where large domestic pets are kept in the home.

[0020] Using a PIR sensor in conjunction with a structurally improved Fresnel lens, it can detect biological motion signals in each area in a segmented manner. It can detect human motion signals, is simple to set up, occupies little space, and makes data processing even simpler. It is widely used in home security systems, intrusion alarm systems in commercial buildings, and other fields. It has high sensitivity, fast response speed, and low power consumption. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating a human motion recognition and detection method provided by the present invention; Figure 2 This is a logic diagram of steps S3-S6 in a human motion recognition and detection method provided by the present invention; Figure 3 This is a schematic diagram of the detection range of the Fresnel lens and PIR sensor provided by the present invention; Figure 4 This is a schematic diagram comparing the test waveforms of a human and a cat under the same period, with PIR signal as the vertical axis and sampling time as the horizontal axis, provided by the present invention. Figure 5 This is a schematic diagram comparing the test waveforms of a human and a cat under the same period, with PIR signal as the vertical axis and sampling time as the horizontal axis, provided by the present invention. Figure 6 This is a structural principle block diagram of a PIR detector provided by the present invention; Figure 7This is a circuit diagram of the signal amplification and refining unit provided by the present invention; Figure 8 This is a schematic diagram of the Fresnel lens provided by the present invention.

[0022] The attached figures are labeled as follows: 1. Fresnel lens; 121. Near-field detection; 122. Mid-field detection; 123. Far-field detection; 2. PIR sensor; 3. Signal amplification and processing unit; 4. Control unit; 5. First voltage analysis unit; 6. Storage unit; 7. Second voltage analysis unit; 8. Slope analysis unit; 9. Third voltage analysis unit; 10. Effective signal quantity analysis unit; 11. Fourth voltage analysis unit. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0024] In this embodiment, as Figure 1-2 As shown, the present invention discloses a human motion recognition and detection method, which includes the following steps: S1: In the area to be detected, the pyroelectric infrared signal of the target is acquired in real time at the first sampling frequency. After the acquired signal is amplified, the real-time pyroelectric infrared amplified signal is obtained and the process proceeds to step S2.

[0025] Specifically, at the first sampling frequency, the pyroelectric infrared signal of the target is continuously sampled without interruption to obtain the real-time pyroelectric infrared amplified signal of the target.

[0026] In this embodiment, the detection range of the detection target is set with moving organisms as reference. In particular, it can detect moving human bodies with a height of 150cm or more, a weight of 40kg or more, and a standard movement speed of 0.5m / s-1.5m / s in an indoor environment, and exclude the situation of sudden jumping of human bodies, so that the human body can maintain a stable walking.

[0027] When collecting pyroelectric infrared signals from the target, a PIR sensor combined with a Fresnel lens is used. The PIR sensor is electrically connected to a signal amplification and processing unit to amplify the collected pyroelectric infrared signals in multiple stages to obtain real-time amplified pyroelectric infrared signals.

[0028] A PIR sensor is a temperature-sensitive sensor. When a human or pet enters the detection area, the temperature of the human or pet differs from the ambient temperature, creating a temperature difference. Therefore, the PIR sensor outputs a voltage signal. However, when the human or pet remains stationary after entering the detection area, the temperature does not change, and the PIR sensor does not output a voltage signal. Thus, it can detect moving human or pets.

[0029] Among them, such as Figure 8 As shown, the principle of combining the Fresnel lens 1 and the PIR sensor 2 is as follows: The Fresnel lens 1 includes a near-field detection area 121, a middle detection area 122, and a far-field detection area 123 distributed sequentially from bottom to top, and each detection area includes multiple lens units. Therefore, the Fresnel lens 1 can divide the area to be detected into regions, so that each lens unit in different regions of the Fresnel lens 1 corresponds to a unique region, and the biological motion signal in each region is focused by the lens unit and refracted onto a PIR sensor 2 to collect the pyroelectric infrared signal.

[0030] In this embodiment, the number of lens units in the near detection zone 121, the middle detection zone 122, and the far detection zone 123 increases sequentially. Furthermore, the tooth depth of the lens units in the near detection zone 121, the middle detection zone 122, and the far detection zone 123 decreases sequentially. By regularly setting the number and tooth depth of each lens unit in the near detection zone 121, the middle detection zone 122, and the far detection zone 123, the deviation in the electrical signal values ​​of the thermal radiation from the same target in the near, middle, and far regions is reduced. This ensures that the output energy of the same target on the PIR sensor 2 is consistent throughout the entire detection area, resulting in a regular electrical signal fed back to the PIR sensor 2. This makes the collected pyroelectric infrared signal more accurate, eliminating interference from electrical signal changes when the same human or pet moves between different detection zones. This lays a solid foundation for the data validity of the detection method, enabling the differentiation of motion waveforms between humans and pets using the corresponding detection method.

[0031] like Figure 7 As shown, in this embodiment, the signal amplification and processing unit 3 includes an interface U2 electrically connected to the PIR sensor 2 and a PIR signal terminal electrically connected to the control unit 4. An operational amplifier circuit (including operational amplifier U4-A) and a secondary operational amplifier circuit (including operational amplifier U4-B) are sequentially connected between the interface U2 and the PIR signal terminal. The output terminals of the operational amplifier circuit, the secondary operational amplifier circuit, and the interface U2 are respectively connected to channel analog switches electrically connected to the control unit 4, namely SW1, SW2, and SW3. By simulating a signal fault, no signal is output at the corresponding position. The amplification factor can also be adjusted according to the signal saturation to achieve the required signal strength, making the signal easier to identify.

[0032] S2: Based on the pyroelectric infrared amplified signal, record the pyroelectric infrared amplified signal as a sample.

[0033] Specifically, voltage analysis is performed on the collected pyroelectric infrared amplified signal. If the voltage value of the pyroelectric infrared amplified signal is greater than or equal to the first voltage threshold, it is preliminarily determined that the target is biological movement. The pyroelectric infrared amplified signal after the first voltage threshold is recorded as a sample, and then the process proceeds to step S3. Otherwise, the process returns to step S1.

[0034] The first voltage threshold can be between 2.8V and 3.0V, specifically set to 2.8V. Only when a pyroelectric infrared amplified signal greater than or equal to the first voltage threshold is the subsequently acquired signal considered accurate and valid.

[0035] S3: Collect and save all the samples within the first sampling period, and determine whether the target being detected is a biological movement based on the samples.

[0036] A first number of samples are collected and saved at the second sampling frequency. Then, the voltage values ​​of all samples in the first half of the first sampling period are averaged and voltage analysis is performed. If the average voltage value is greater than or equal to the first voltage threshold, the detection target is determined to be biological motion, and the process proceeds to step S4.

[0037] Step S3 specifically includes four steps: S31-S34.

[0038] S31: After the pyroelectric infrared amplified signal is greater than or equal to the first voltage threshold, the pyroelectric infrared signal is continuously sampled at the second sampling frequency and the process proceeds to step S32. The second sampling frequency is set to be greater than or equal to the first sampling frequency; in this embodiment, the second sampling frequency is 1000Hz.

[0039] In some embodiments, the first sampling frequency is 1000Hz, and the next moment of the pyroelectric infrared amplified signal that is greater than or equal to the first voltage threshold is the next moment of the corresponding pyroelectric infrared amplified signal according to the first sampling frequency; that is, after acquiring the pyroelectric infrared amplified signal that is greater than or equal to the first voltage threshold for 1ms, sampling continues to be performed according to the second sampling frequency to obtain samples.

[0040] In another embodiment, the first sampling frequency is 1000Hz, and the next moment of the pyroelectric infrared amplified signal that is greater than or equal to the first voltage threshold is the next moment of the corresponding pyroelectric infrared amplified signal according to the second sampling frequency; wherein, the second sampling frequency is 2000Hz, that is, after acquiring the pyroelectric infrared amplified signal that is greater than or equal to the first voltage threshold for 0.5ms, sampling continues according to the second sampling frequency to obtain samples.

[0041] S32: Determine whether the number of samples acquired at the second sampling frequency has reached the first number. If the number of samples acquired has reached the first number, save the first number of samples acquired at the second sampling frequency and proceed to step S33; otherwise, return to step S31.

[0042] Since the set movement cycle of the human body within the established detection range is 1.5-2.5 seconds, theoretically, the first sampling period is between 1.5 and 2.5 seconds. The first sampling period is equal to the product of the sampling frequency and the number of samples. Based on the above formula, the second sampling frequency and the first number of samples can be set. Firstly, the setting of the first number is determined by the data processing capability of the control unit. Generally, 1000-5000 samples can be collected within one first sampling period. When the second sampling frequency is 1000Hz, i.e., sampling once every 1ms, the first number needs to include 1500-2500 samples to constitute a complete first sampling period. In this embodiment, sampling is performed once every 1ms, collecting a total of 2000 samples. Therefore, the first sampling period is 1ms. 2000 = 2s.

[0043] S33: Calculate the average voltage of all samples in the first half of the first sampling period using the averaging method, and then proceed to step S34.

[0044] like Figure 4 , 5 As shown, since the distribution of samples over the sampling time is roughly waveform-like, a waveform test diagram is used to display the peak value, motion period, and waveform amplitude for ease of explanation. However, the detection method of this invention does not require analysis of the data based on the waveform test diagram. The peak value is the position of the waveform's crest, i.e., the sample with the highest voltage value; the waveform amplitude is the voltage value corresponding to each point on the waveform. Furthermore, since the waveform of the first half of the sampling period is symmetrical to that of the second half, voltage analysis is only required for the samples in the first half of the sampling period. That is, all samples collected within the first half of the sampling period (i.e., within 1 second) need to be analyzed. Since the number of samples in the first sampling period is 2000, the number of samples in half a sampling period is specifically the first 1000 samples.

[0045] At the first sampling frequency, it is still necessary to compare pyroelectric infrared amplified signals that are less than the first voltage threshold. Therefore, the waveform test diagram also includes sampling time points that are less than the first voltage threshold. Furthermore, since only the sampled data after reaching the first voltage threshold needs to be analyzed in subsequent data analysis, in the actual detection method, before the detected pyroelectric infrared amplified signal is greater than or equal to the first voltage threshold, only the sampled voltage values ​​are compared and judged, and they are not saved.

[0046] The averaging method involves summing the voltage values ​​of all samples in the first half of the sampling period and then dividing by the number of samples in the first half of the sampling period to obtain the average value of that sample. If it is only occasional interference, in the example of a waveform test diagram, it would be a short-duration, high-amplitude spike pulse. This interference signal will be averaged in this step, which will, to some extent, eliminate the influence of the spike pulse on determining whether it is biological motion.

[0047] S34: Compare the average voltage value with the first voltage threshold. If the average voltage value is greater than or equal to the first voltage threshold, determine that the target is biological motion and proceed to step S4. If the average voltage value is less than the first voltage threshold, return to step S1.

[0048] Since the sample voltage values ​​obtained at different sampling time points are different, in order to eliminate signal interference such as light or sampling spikes and ensure that the collected samples are accurate and effective, it is necessary to calculate the average voltage of the samples and then compare the average voltage with the first voltage threshold.

[0049] In one embodiment, the averaging method can also exclude interference from small pets, such as when a small pet occasionally jumps and moves, the voltage value collected is greater than the first voltage threshold, but when further judged based on the average voltage value, it is less than the first voltage threshold.

[0050] S4: Record all saved samples as biological motion samples.

[0051] Based on the saved samples from the first sampling period, the slope of the samples in the first half of the first sampling period is analyzed between different sampling time points to determine whether the slope change is from an upward trend to a downward trend. If the slope change is from an upward trend to a downward trend, all saved samples are recorded as biological motion samples and the process proceeds to step S5. If the slope change is not from an upward trend to a downward trend, the process returns to step S1. This improves the accuracy of the analysis of the pyroelectric infrared amplified signal, eliminates the possibility of a rise in the overall voltage of the sample without slope change due to sensor damage, and avoids false triggering.

[0052] In this embodiment, the slope change is calculated as follows: the first or second derivative of the pyroelectric infrared amplified signal is calculated using conventional differential operations, and then the upward or downward trend of the slope is determined based on the positive or negative change of the corresponding derivative. The upward or downward trend of the slope is reflected in the waveform test graph as an upward or downward trend in the waveform.

[0053] S5: Perform voltage analysis on the voltage value of the biological motion sample in the first half of the sampling period.

[0054] Specifically, the voltage analysis involves determining whether there is a biological motion sample whose voltage value is greater than or equal to the second voltage threshold in the first half of the sampling period. If the voltage value of the biological motion sample is greater than or equal to the second voltage threshold, then the biological motion sample is recorded as a valid signal. It also involves determining whether the number of valid signals is greater than a set proportion of the total number of biological motion samples in the first half of the sampling period. If the number of valid signals is greater than the set proportion, then proceed to step S6; otherwise, return to step S1.

[0055] Specifically, the voltage analysis at this point includes two steps, S51 and S52.

[0056] S51: Compare the voltage value (i.e. the amplitude corresponding to each point on the waveform) of the biological motion sample in the first half of the sampling period with the second voltage threshold, obtain the biological motion sample with a voltage value greater than the second voltage threshold in the first half of the sampling period, and record it as a valid signal. Obtain the number of valid signals and then proceed to step S52.

[0057] In this embodiment, within the set detection range, the second voltage threshold can be between 3.2V and 4V, specifically 3.8V. This setting can exclude the voltage signal output by the PIR sensor during the gentle movement of small domestic pets. The biological movement samples in the first half of the sampling cycle are 1000.

[0058] S52: Compare the number of valid signals with the total number of biological motion samples in the first half of the sampling period. If the number of valid signals is greater than the set proportion of the total number of biological motion samples in the first half of the sampling period, proceed to step S6; if the number of valid signals is less than or equal to the set proportion of the total number of biological motion samples in the first half of the sampling period, return to step S1.

[0059] The set ratio can be 0.5-0.6. In this embodiment, the set ratio is 0.5, that is, the number of valid signals must be more than half of the total number of biological motion samples in the first half of the sampling period. Since there are 1000 biological motion samples in the first half of the sampling period, the process proceeds to step S6 as long as there are more than 500 valid signals.

[0060] S6: Obtain the peak value of the biological motion sample in the first half of the sampling period, and perform voltage analysis on the peak value of the biological motion sample. If it is determined that the peak value of the biological motion sample is greater than or equal to the second voltage threshold, then the target is determined to be human motion. If it is determined that the peak value of the biological motion sample is less than or equal to the third voltage threshold, then the target is determined to be human motion.

[0061] Specifically, the voltage analysis of this peak value includes three steps: S61-S63.

[0062] S61: Using the peak detection method, the peak value of the biological motion sample in the first half of the sampling period is obtained, and then proceed to step S62.

[0063] Specifically, peak values ​​are detected by finding maximum or minimum points in biological motion samples. Conventional difference operations are used to calculate the first or second derivative of the biological motion samples and find the zero-crossing points of the corresponding derivative changes. These points usually correspond to the peak values ​​of the biological motion samples.

[0064] S62: Compare the peak value of the biological motion sample with the second voltage threshold. If the peak value of the biological motion sample is greater than or equal to the second voltage threshold, it is preliminarily determined that the target is human motion and proceeds to step S63. If the peak value of the biological motion sample is less than the second voltage threshold, return to step S1.

[0065] S63: Then compare the peak value of the biological motion sample with the third voltage threshold. When it is determined that the peak value of the biological motion sample is less than or equal to the third voltage threshold, the detection target is determined to be human motion.

[0066] The third voltage threshold can be between 4.2V and 5.0V; in this embodiment, it is specifically set to 4.8V. This setting allows for the detection of abnormal movements in pets, such as jumping, where the PIR sensor outputs a higher voltage signal, resulting in a peak value exceeding the third voltage threshold. This helps to mitigate interference from the pet's jumping movements. In one embodiment, this peak value determination can exclude interference from medium to large-sized pets. For example, the signal voltage value collected when a medium to large-sized pet is walking normally is greater than or equal to the second voltage threshold, but when it jumps, the signal voltage value will be greater than the third voltage threshold.

[0067] Since the waveform amplitude, peak value of biological motion sample, first sampling period and voltage threshold values ​​mentioned above are affected by human height, weight and movement speed, they can be adjusted according to the test situation and application scenario.

[0068] Within the same detection area, taking a common-sized domestic pet as an example, the peak value of the human body output by the PIR sensor is greater than that of the pet. In this embodiment, as... Figure 3 As shown, the horizontal axis represents the horizontal distance between a person or pet and the PIR sensor, and the vertical axis represents the vertical distance between the person or pet and the PIR sensor. The human figure is defined as an adult 160cm tall and weighing 60kg, and the pet figure is defined as a pet less than 80cm tall and weighing less than 45kg. Figure 4 As shown, the peak value of the human body output by the PIR sensor is greater than that of the pet, and the points that constitute the PIR signal waveform correspond to biological motion samples.

[0069] Waveform test diagrams can also illustrate the differences in movement between humans and domestic pets, with the common domestic pet being the cat. Figure 5 As shown, in this embodiment, the pet's movement cycle includes a portion of normal walking or gentle movement, and a portion of jumping or rapid movement. Within a complete movement cycle (i.e., 2 seconds), when the pet is performing normal walking or gentle movement, the time period of normal walking in the pet's waveform is no more than 1 second; and the waveform amplitude is small, not reaching the first voltage threshold; the pyroelectric infrared amplified signal output by the signal amplification and processing unit is excluded when entering step S2. When the pet is performing jumping or rapid movement, the time period of jumping in the pet's waveform is no more than 1 second; and the waveform amplitude is large, with the peak value exceeding the third voltage threshold. When a human is moving, refer to the human waveform; this waveform has a long and gentle cycle, and at least half of the samples in the waveform within the first second have a voltage value greater than the second voltage threshold. Therefore, by judging the number of effective signals in the biological movement samples and the peak value of the biological movement samples, it is possible to determine whether the detected target is human movement or domestic pet movement.

[0070] like Figure 6 As shown, the present invention also provides a PIR detector employing the aforementioned human motion recognition detection method. The PIR detector includes: a Fresnel lens 1 for performing zoned focusing to achieve zoned recognition of the target within the detection area; a PIR sensor 2 disposed at the rear end of the Fresnel lens 1 to receive the infrared radiation focused by the Fresnel lens 1 to obtain a pyroelectric infrared signal; a signal amplification and processing unit 3 electrically connected to the PIR sensor 2 for performing multi-stage amplification and processing of the pyroelectric infrared signal to obtain a real-time pyroelectric infrared amplified signal; and a control unit 4 including an MCU.

[0071] The first voltage analysis unit 5 is used to perform voltage analysis on the pyroelectric infrared amplified signal in the aforementioned detection method. In one embodiment, the first voltage analysis unit 5 is located inside the MCU.

[0072] Storage unit 6 is used to implement the function of saving the first number of samples collected at the second sampling frequency in the aforementioned detection method. In one embodiment, storage unit 6 is disposed inside control unit 4. In another embodiment, storage unit 6 is disposed in a separate memory, and the MCU and the memory can communicate with each other.

[0073] The second voltage analysis unit 7 is used to implement the voltage analysis function in the aforementioned detection method, which involves averaging the voltage values ​​of all samples in the first half of the first sampling period. In one embodiment, the second voltage analysis unit 7 is located inside the MCU.

[0074] The slope analysis unit 8 is used to implement the function of analyzing the slope of the sample between different sampling time points in the first half of the first sampling period in the aforementioned detection method. In one embodiment, the slope analysis unit 8 is located inside the MCU.

[0075] The third voltage analysis unit 9 is used to determine whether the voltage value of a biological moving sample is greater than or equal to the second voltage threshold in the first half of the sampling period of the aforementioned detection method. In one embodiment, the third voltage analysis unit 9 is located inside the MCU.

[0076] The effective signal quantity analysis unit 10 is used to implement the function of judging the quantity of effective signals in the aforementioned detection method. In one embodiment, the effective signal quantity analysis unit 10 is disposed inside the MCU.

[0077] The fourth voltage analysis unit 11 is used to perform voltage analysis on the peak value of the biological motion sample in the aforementioned detection method. In one embodiment, the fourth voltage analysis unit 11 is located inside the MCU.

[0078] The control unit 4 is used to control the working status of the first voltage analysis unit 5, the storage unit 6, the second voltage analysis unit 7, the slope analysis unit 8, the third voltage analysis unit 9, the effective signal quantity analysis unit 10, and the fourth voltage analysis unit 11 respectively according to the aforementioned detection method.

[0079] The PIR detector also includes a power supply unit to power the control unit 4 and the electronic components in the PIR detector.

[0080] like Figure 8 As shown, to avoid the inconsistent and irregular energy collected by a conventional Fresnel lens 1 at different distances for a target of the same volume and temperature, resulting in an irregular electrical signal reflected on the PIR sensor 2, it is impossible to distinguish between human and non-human movement through subsequent algorithms.

[0081] Based on the principles of PIR sensor 2 and Fresnel lens 1, the focusing capability is altered by changing the lens structure. Fresnel lens 1 is divided into three regions: a near-field detection region 121, a middle-field detection region 122, and a far-field detection region 123, distributed sequentially from bottom to top. Each detection region includes multiple lens units, with the number of lens units increasing sequentially from near-field to far-field. Furthermore, the tooth depth of the lens units decreases sequentially from near-field to far-field. Fresnel lens 1 enables the focusing, collection, and dispersion of light, improving the performance and efficiency of optical equipment. The staggered arrangement of the centers of individual lens units in each detection region effectively reduces blind spots in the detection area. Moreover, the larger the area of ​​the lens unit, the more infrared light it receives, resulting in a stronger signal.

[0082] By simply placing the PIR sensor 2 at a height of 1-3 meters above the ground and an installation angle of 15-30°, ensuring that the Fresnel lens 1 is parallel to the PIR sensor 2, an area up to 20 meters away from the PIR sensor 2 can be detected. The installation height and angle are determined based on the installation environment, and the actual detection range depends on the structure of the Fresnel lens 1 and the power of the PIR sensor 2. Figure 3 As shown, in this embodiment, the detection range of the far-field detection is 6-9m, the detection range of the middle-field detection is 4-6m, and the detection range of the near-field detection is 2-4m. By increasing the power of the PIR sensor 2, the detection range of each detection area can be expanded.

[0083] The signal is weaker at locations far from the heat source. Multiple lens units can be used to focus the signal, converging multiple weak signals onto the PIR sensor 2. After being amplified by the signal amplification and processing unit 3, the signal becomes close to that of the near-field detection area 121. The lens units in the far-field detection area 123 have shallower tooth depths, enhancing the reception of light signals and making them suitable for long-distance detection.

[0084] The signal is stronger at locations closer to the heat source, allowing for focusing with fewer lenses. This concentrates a smaller amount of strong signal onto the PIR sensor 2, where it is amplified by the signal amplification and processing unit 3 to reach a signal close to that of the detection range 123. The lens unit in the near-field detection range 121 has deeper teeth, weakening the light signal and making it suitable for close-range detection.

[0085] The signal at the midpoint of the heat source is moderate. Using an appropriate lens to focus the signal, the appropriate amount of signal is converged to the PIR sensor 2. After being amplified by the signal amplification and processing unit 3, the signal in the detection middle area 122 is close to that in the detection far area 123 and the detection near area 121.

[0086] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A method for human motion recognition and detection, characterized in that, The steps include the following: Within the area to be detected, the pyroelectric infrared signal of the target is acquired in real time at the first sampling frequency, and the acquired signal is amplified to obtain the real-time pyroelectric infrared amplified signal. Based on the pyroelectric infrared amplified signal, the pyroelectric infrared amplified signal is recorded as a sample; Collect and save all the samples within the first sampling period, and determine whether the detection target is biological movement based on the samples; If the target of the detection is determined to be biological motion, all the saved samples will be recorded as biological motion samples; The peak value of the biological motion sample in the first half of the sampling period is obtained, and voltage analysis is performed on the peak value of the biological motion sample. The peak value of the biological motion sample is compared with a second voltage threshold. If it is determined that the peak value of the biological motion sample is greater than or equal to the second voltage threshold, the detection target is initially determined to be human motion. Then, the peak value of the biological motion sample is compared with a third voltage threshold. If it is determined that the peak value of the biological motion sample is less than or equal to the third voltage threshold, the detection target is determined to be human motion.

2. The human motion recognition and detection method as described in claim 1, characterized in that, The method for obtaining the peak value of biological motion samples in the first half of the sampling period includes the following steps: The peak value of the biological motion sample in the first half of the sampling period was obtained by using the peak detection method.

3. The human motion recognition and detection method as described in claim 1, characterized in that, Before obtaining the peak value of the biological motion samples in the first half of the sampling period, the following steps are also included: Voltage analysis is performed on the voltage values ​​of the biological motion samples in the first half of the sampling period, specifically including: Determine whether there is a biological motion sample whose voltage value is greater than or equal to a second voltage threshold in the first half of the sampling period. If the voltage value of the biological motion sample is greater than or equal to the second voltage threshold, then the biological motion sample is recorded as a valid signal. Determine whether the number of valid signals is greater than a set proportion of the total number of biological motion samples in the first half of the sampling period. If the number of valid signals is greater than the set proportion, then obtain the peak value of the biological motion samples in the first half of the sampling period.

4. The human motion recognition and detection method as described in claim 1, characterized in that, The process of collecting and storing all samples within the first sampling period, and determining whether the detected target is a biological movement based on the samples, includes the following steps: A first number of samples are collected and saved at a second sampling frequency. Then, the voltage values ​​of all samples in the first half of the first sampling period are averaged and voltage analysis is performed. If the average voltage value is greater than or equal to a first voltage threshold, the detection target is determined to be biological motion. Wherein, the first sampling period is equal to the product of the second sampling frequency and the first quantity.

5. The human motion recognition and detection method as described in claim 4, characterized in that, The process of collecting and storing a first number of samples at a second sampling frequency, then averaging the voltage values ​​of all samples in the first half of the first sampling period and performing voltage analysis, and determining the detection target as biological motion if the average voltage is greater than or equal to a first voltage threshold, includes the following steps: The pyroelectric infrared amplified signal continues to be sampled at the second sampling frequency; Determine whether the number of samples acquired at the second sampling frequency reaches the first number. When it is determined that the number of acquired samples reaches the first number, save the first number of samples acquired at the second sampling frequency. Then, use the averaging method to calculate the average voltage of all samples in the first half of the first sampling period. The average voltage is compared with the first voltage threshold. If the average voltage is greater than or equal to the first voltage threshold, the detection target is determined to be biological motion.

6. The human motion recognition and detection method as described in claim 4, characterized in that, The step of recording the pyroelectric infrared amplified signal as a sample based on the pyroelectric infrared amplified signal includes the following steps: Voltage analysis is performed on the collected pyroelectric infrared amplified signal. If the voltage value of the pyroelectric infrared amplified signal is greater than or equal to a first voltage threshold, it is preliminarily determined that the detected target is biological motion, and the pyroelectric infrared amplified signal after the first voltage threshold is recorded as a sample.

7. The human motion recognition and detection method according to any one of claims 1-6, characterized in that, The acquisition of the pyroelectric infrared signal of the target is achieved using a PIR sensor combined with a Fresnel lens.

8. The human motion recognition and detection method as described in claim 7, characterized in that: The PIR sensor is electrically connected to the signal amplification and processing unit, which amplifies the collected pyroelectric infrared signal in multiple stages to obtain a real-time pyroelectric infrared amplified signal. The signal amplification and processing unit (3) includes an interface electrically connected to the PIR sensor (2) and a PIR signal terminal electrically connected to the control unit (4). An operational amplifier circuit and a secondary operational amplifier circuit are sequentially connected between the interface and the PIR signal terminal. The output terminal of the operational amplifier circuit, the output terminal of the secondary operational amplifier circuit, and the interface are respectively connected to a channel analog switch electrically connected to the control unit (4).

9. The human motion recognition and detection method according to any one of claims 1-6, characterized in that, All saved samples are recorded as biological motion samples, including the following steps: The slope of the samples in the first half of the first sampling period is analyzed between different sampling time points to determine whether the slope change of the sample is from an upward trend to a downward trend. If the slope change of the sample is from an upward trend to a downward trend, then all the saved samples are recorded as biological motion samples.

10. A PIR detector, characterized in that, The human motion recognition and detection method as described in any one of claims 1-9 is adopted.

11. The PIR detector as claimed in claim 10, characterized in that, The PIR detector includes: Fresnel lens (1) is used for zonal focusing to achieve zonal identification of the target in the area to be detected; PIR sensor (2) is located at the rear end of Fresnel lens (1) and receives infrared radiation focused by Fresnel lens (1) to obtain pyroelectric infrared signal; The signal amplification and processing unit (3) is electrically connected to the PIR sensor (2) and is used to amplify and process the pyroelectric infrared signal in multiple stages to obtain the real-time pyroelectric infrared amplified signal. The first voltage analysis unit (5) is used to perform voltage analysis on the pyroelectric infrared amplified signal in the aforementioned detection method; Storage unit (6) is used to implement the function of saving the first number of samples collected at the second sampling frequency in the aforementioned detection method; The second voltage analysis unit (7) is used to perform voltage analysis by averaging the voltage values ​​of all samples in the first half of the first sampling period in the aforementioned detection method. The slope analysis unit (8) is used to implement the function of analyzing the slope of the sample in the first half of the sampling period of the first sampling period between different sampling time points in the aforementioned detection method. The third voltage analysis unit (9) is used to determine whether the voltage value of a biological motion sample is greater than or equal to the second voltage threshold in the first half of the sampling period of the aforementioned detection method. The effective signal quantity analysis unit (10) is used to realize the function of judging the quantity of the effective signals in the aforementioned detection method; The fourth voltage analysis unit (11) is used to perform voltage analysis on the peak value of the biological motion sample in the aforementioned detection method; The control unit (4) is used to control the working status of the first voltage analysis unit (5), the storage unit (6), the second voltage analysis unit (7), the slope analysis unit (8), the third voltage analysis unit (9), the effective signal quantity analysis unit (10), and the fourth voltage analysis unit (11) according to the aforementioned detection method.

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