Human body moving direction identification method based on one-dimensional Fresnel array

Abstract

The invention belongs to the field of detection, and particularly relates to a human body moving direction identification method based on a one-dimensional Fresnel array, the identification method adopts an infrared induction probe, a Fresnel lens and a control module, and the Fresnel lens is provided with a one-dimensional Fresnel array area. The infrared induction probe detects a wavelength signal emitted by human body infrared through the one-dimensional Fresnel array area so as to output a corresponding voltage signal waveform to the control module, and the control module recognizes the moving direction of the human body according to the voltage signal waveform. According to the invention, human body images are not directly collected, so that the dispute of privacy disclosure is avoided, and the multi-scene compatibility of the infrared sensing probe is better; besides, in the recognition method, human body movement recognition can be completed only through one infrared induction probe, the equipment hardware cost is lower, and ultra-low power consumption can be achieved.

Description

Technical Field

[0001] The present invention belongs to the field of detection, and particularly relates to a method for identifying the moving direction of a human body based on a one-dimensional Fresnel array. Background Art

[0002] With the rapid development of intelligent sensing technology, the demand for human body movement recognition in the fields of intelligent security, health monitoring, human-computer interaction, etc. is increasing day by day. In the prior art, human body movement recognition is mainly realized based on vision recognition technology. Traditional monitoring systems rely on cameras and image processing algorithms (such as optical flow method, background modeling) to detect human body movement. However, such technologies have obvious defects: 1. The camera directly collects the user's image, which is likely to cause disputes over privacy leakage; 2. Insufficient light, occlusions, and complex backgrounds will significantly reduce the recognition accuracy. Summary of the Invention

[0003] In order to solve the above problems, the primary object of the present invention is to provide a method for identifying the moving direction of a human body based on a one-dimensional Fresnel array, which has better privacy protection and multi-scenario compatibility.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows.

[0005] A method for identifying the moving direction of a human body based on a one-dimensional Fresnel array, the identification method uses an infrared induction probe, a Fresnel lens, and a control module, wherein a one-dimensional Fresnel array area is provided on the Fresnel lens, and the infrared induction probe detects the wavelength signal emitted by the human body's infrared through the one-dimensional Fresnel array area to output a corresponding voltage signal waveform to the control module, and the control module identifies the moving direction of the human body based on the voltage signal waveform.

[0006] In the present invention, the infrared induction probe detects the wavelength signal emitted by the human body's infrared through the one-dimensional Fresnel array area, and the control module identifies the moving direction of the human body based on the voltage signal waveform. During this process, the human body image is not directly collected, avoiding disputes over privacy leakage, and the infrared induction probe has better multi-scenario compatibility; in addition, in this identification method, only one infrared induction probe is required to complete the human body movement recognition, which not only has lower device hardware cost but also can achieve ultra-low power consumption. Brief Description of the Drawings

[0007] Figure 1 It is a flowchart for the control module to identify the moving direction of the human body based on the voltage signal waveform.

[0008] Figure 2 It is a schematic diagram of the equivalent circuit of the infrared probe.

[0009] Figure 3 It is a schematic diagram of the one-dimensional Fresnel array area.

[0010] Figure 4 It is a schematic diagram of a multi-dimensional Fresnel array area.

[0011] Figure 5 It is a schematic diagram of the signal output of an infrared induction probe to an amplifier circuit.

[0012] Figure 6 It is a waveform diagram of human body movement from left to right. Specific implementation manners

[0013] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] See Figures 1-6 , the present invention provides a method for identifying the moving direction of a human body based on a one-dimensional Fresnel array. The identification method uses an infrared induction probe, a Fresnel lens and a control module. A one-dimensional Fresnel array area is provided on the Fresnel lens. The infrared induction probe detects the wavelength signal emitted by the human body's infrared through the one-dimensional Fresnel array area to output a corresponding voltage signal waveform to the control module. The control module identifies the moving direction of the human body based on the voltage signal waveform. In this process, there is no need to directly collect the human body image, avoiding disputes over privacy leakage.

[0015] In this embodiment, as for the infrared induction probe, the infrared induction probe can be composed of four parts:

[0016] Filter: Filter out infrared rays of other wavelengths emitted by non-human bodies; it is worth noting that the wavelength of infrared rays emitted by the human body is specific (generally about 10uM). By adding a filter, it is possible to allow only infrared rays of a specific wavelength (7-14uM) to enter the infrared induction probe. Through the selection function of the filter, it can be ensured that the infrared induction probe is only sensitive to human body infrared rays, thereby reducing environmental interference.

[0017] Induction unit: When certain crystals (such as lithium tantalate, triglycine sulfate, etc.) are heated by infrared radiation, the surface charge will decrease, which is equivalent to releasing a part of the charge. This phenomenon is called the pyroelectric effect; therefore, the induction unit can be made of materials with high pyroelectric coefficients, such as lead zirconate titanate-based ceramics, lithium tantalate, triglycine titanate, etc. These materials will generate charge changes when receiving infrared radiation;

[0018] Amplifier: The infrared induction probe amplifies and converts the released charge signal into a voltage output through a MOS transistor, thereby realizing the detection of infrared radiation;

[0019] Socket: Combine and package the filter, induction unit, and amplifier into an infrared induction probe.

[0020] Specifically, the sensing unit of the infrared sensing probe is perpendicular to the one-dimensional Fresnel array area.

[0021] Regarding the infrared sensing probe, referring to Figure 2 the equivalent circuit of the infrared sensing probe, it can be known that there are two sensing elements in the sensing unit; when the infrared radiation of the human body passes through the one-dimensional Fresnel array area of the Fresnel lens and is received by the sensing elements, based on the different heat received by the two sensing elements, the generated charges are also different and cannot be offset. Therefore, the output detection signal can be obtained through this.

[0022] It should be noted that when the infrared ray IR emitted by the human body moves vertically from top to bottom or from bottom to top with respect to the mirror surface, there is a sequence in the infrared rays received by the two sensing elements. During this process, one of the sensing elements will generate charges first. As the movement progresses, the light on this sensing element decreases and the charges decrease, while the light incident on the other sensing element increases and gradually generates charges. For the same moving direction, a fixed current direction can be obtained, and due to the existence of RG, the current is converted into a voltage signal.

[0023] Therefore, as long as it is perpendicular to the mirror surface and the two photosensitive elements receive light successively, different voltage signal waveforms can appear. So, by determining the direction of the window of the infrared sensing probe, when the human body moves from left to right and from right to left relatively, different voltage signal waveforms can be obtained.

[0024] Regarding the Fresnel lens, the Fresnel lens is a threaded lens injection-molded from polyolefin materials (it can also be made of glass), with one side of the lens surface being smooth and the other side engraved with concentric circles from small to large. Referring to Figure 3 this one-dimensional Fresnel array, it takes the adjustment of a larger range of external light into concentrating the light at one place to form a central focus, in order to cooperate with the above-mentioned infrared sensing probe in receiving the infrared rays emitted by the human body, so that the infrared sensing probe generates a current in a fixed direction for the movement in the same direction.

[0025] Specifically, when the human body moves from left to the middle, at this stage, the focus gradually moves from below the infrared sensing probe to the sensing element located below; during this stage, the charge of the lower sensing element changes from zero to non-zero, and the light first shines on the lower sensing element, generating a clockwise flowing current; continuing to move, when the entire focus is completely on the sensing element, the current reaches the maximum value; continuing to move, the focus gradually moves out of the sensing element and the current decreases; when the person reaches the middle, the focus is between the two sensing elements and the current is zero.

[0026] The human body moves from the middle to the right. During this stage, the focus gradually moves from the middle of the two sensors to above the infrared sensor probe. During this stage, the charge of the upper sensor changes from zero to non-zero. The light first shines on the upper sensor, generating a current that flows counterclockwise. As the movement continues, when the entire focus is completely on the sensor, the current reaches its maximum value. As the movement continues further, the focus gradually moves out of the sensor and the current decreases. When the person reaches the right side, the focus moves above the infrared sensor probe and the current becomes zero.

[0027] See Figure 4 , it should be emphasized that if it is a two-dimensional or more two-dimensional array lens (two or more partitions), it will cause the problem of light interference, making the direction of the current generated by the infrared sensor probe not fixed, and the recognition method in this application cannot be realized.

[0028] In this embodiment, the voltage signal waveform includes a sine signal corresponding to the human body moving from left to right and a negative sine signal corresponding to the human body moving from right to left.

[0029] Specifically, see Figure 5 , the positive terminal of the amplifier is connected to 1 / 2 of the power supply voltage, and the negative terminal is connected to the signal of the infrared sensor probe. In this way, the output signal is a signal that fluctuates above and below 1 / 2 of the power supply voltage. The maximum amplitude is the power supply voltage, and the minimum amplitude is 0V. It can be determined that the zero point of the signal is 1 / 2 of the power supply voltage;

[0030] When powered by a 2V power supply, the waveform corresponding to the human body moving from left to right is shown in Figure 6 , which is a sine signal: The movement of the human body from right to left is the reverse process of the above process. Similarly, it can be deduced that it is a negative sine signal.

[0031] In this embodiment, the control module confirms the signal data of the zero point value when the infrared sensor probe does not detect a human body. The signal data of this zero point value is specifically the signal data when it is 1 / 2 of the power supply voltage. The process by which the control module identifies the human body movement direction based on the voltage signal waveform includes the following steps:

[0032] Step 1: Continuously read the signal data of the infrared sensor probe;

[0033] Step 2: Determine whether the signal data continuously remains at the zero point value; if not, return to Step 1; if yes, proceed to Step 3;

[0034] Step 3: Continuously read the signal data of the infrared sensor probe and judge the waveform of the read signal data of the infrared sensor probe;

[0035] Step 4: Judge the human body movement direction according to the waveform of the signal data of the infrared sensor probe.

[0036] In this embodiment, a data retention period is set to only retain signal data within a certain period of time in real time; specifically, step 1 is as follows: Continuously read the signal data of the infrared induction probe and save it in an array; the array saves the signal data within the data retention period, and saves it recursively, with the first-in, first-out principle.

[0037] In this embodiment, the data retention period is 1S. That is to say, the array only retains the signal data within 1S in real time, saves it recursively, with the first-in, first-out principle.

[0038] In this embodiment, the control module sets a threshold for determining whether the signal data continuously remains at the zero value. The threshold is 0.2V (which can also be dynamically adjusted according to the actual situation). Step 2 specifically includes the following steps:

[0039] Step 2.1: Judge whether the difference between the maximum value and the minimum value in the array is less than the threshold; if not, return to step 1; if so, enter step 2.2;

[0040] Step 2.2: Judge whether the difference between all the signal data in the array and the signal data at the zero value is less than the threshold; if not, return to step 1; if so, enter step 3.

[0041] In this embodiment, a duration value is set. Step 3 includes the following steps:

[0042] Step 3.1: Continuously read the signal data of the infrared induction probe, and calculate the difference between the current value of the signal data of the infrared induction probe read in real time and the average value of the array, and mark the value of the current value whose difference is greater than the threshold;

[0043] Step 3.2: Judge whether the duration of the marked value is greater than the duration value; if not, return to step 3.1; if so, enter step 3.3;

[0044] Step 3.3: Judge the change trend of the difference between the marked signal data and the signal data at the zero value to confirm the waveform of the change of the marked signal data.

[0045] It should be noted that when the control module confirms the waveform of the change of the marked signal data, it is based on the characteristics of the extracted sine waveform and negative sine waveform, and fits the change of the signal data with the characteristics of the extracted sine waveform and negative sine waveform to confirm the waveform of the change of the signal data; specifically, the sine waveform starts from zero and rises first; the negative sine waveform starts from zero and falls first.

[0046] In this embodiment, the duration value is 100ms.

[0047] In this embodiment, in step 4, after judging the human movement direction, process the human movement direction and return to step 1.

[0048] In this embodiment, in step 4, processing the human movement direction includes controlling the voice IC to perform voice broadcast.

[0049] In this embodiment, the control module is an MCU, which continuously reads the signal data of the infrared induction probe by reading the AD value of the signal pin. Specifically, the model of the MCU can preferably be FT61EC23.

[0050] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for identifying the moving direction of a human body based on a one-dimensional Fresnel array, characterized in that This recognition method uses an infrared induction probe, a Fresnel lens, and a control module. There is a one-dimensional Fresnel array area on the Fresnel lens. The infrared induction probe detects the wavelength signal emitted by the human body through the one-dimensional Fresnel array area to output a corresponding voltage signal waveform to the control module, and the control module identifies the moving direction of the human body based on the voltage signal waveform.

2. The human body movement direction recognition method based on a one-dimensional Fresnel array according to claim 1, wherein, The voltage signal waveform includes a sine signal corresponding to the human body moving from left to right and a negative sine signal corresponding to the human body moving from right to left.

3. The human body movement direction recognition method based on a one-dimensional Fresnel array according to claim 2, wherein The control module confirms the signal data of the zero value when the infrared induction probe does not detect the human body, and the process of the control module identifying the moving direction of the human body based on the voltage signal waveform includes the following steps: Step 1: Continuously read the signal data of the infrared induction probe. Step 2: Determine whether the signal data continuously remains at the zero value; if not, return to Step 1; if yes, enter Step 3. Step 3: Continuously read the signal data of the infrared induction probe and judge the waveform of the signal data read from the infrared induction probe. Step 4: Judge the moving direction of the human body according to the waveform of the signal data of the infrared induction probe.

4. The human body movement direction recognition method based on a one-dimensional Fresnel array according to claim 3, wherein There is a data retention period. Step 1 is specifically: continuously read the signal data of the infrared induction probe and save it in an array; the array saves the signal data within the data retention period, and saves it recursively, first in first out.

5. A method for identifying the moving direction of a human body based on a one-dimensional Fresnel array according to claim 4, characterized in that, The data retention period is 1S.

6. A method for identifying the moving direction of a human body based on a one-dimensional Fresnel array according to claim 4, characterized in that The control module sets a threshold for determining whether the signal data continuously remains at the zero value. Step 2 specifically includes the following steps: Step 2.1: Judge whether the difference between the maximum value and the minimum value in the array is less than the threshold; if not, return to Step 1; if yes, enter Step 2.

2. Step 2.2: Judge whether the difference between all the signal data in the array and the signal data of the zero value is less than the threshold; if not, return to Step 1; if yes, enter Step 3.

7. The human body movement direction recognition method based on a one-dimensional Fresnel array according to claim 6, characterized in that, There is a set duration value. Step 3 includes the following steps: Step 3.1: Continuously read the signal data of the infrared induction probe, and subtract the current value of the signal data read from the infrared induction probe in real time from the average value of the array, and mark the value of the current value whose difference is greater than the threshold. Step 3.2: Judge whether the duration of the marked value is greater than the duration value; if not, return to Step 3.1; if yes, enter Step 3.

3. Step 3.3: Judge the change trend of the difference between the marked signal data and the signal data of the zero value to confirm the waveform of the change of the marked signal data.

8. A method for identifying the moving direction of a human body based on a one-dimensional Fresnel array according to claim 7, characterized in that, The duration value is 100ms.

9. A method for identifying the moving direction of a human body based on a one-dimensional Fresnel array according to claim 1, characterized in that, In Step 4, after judging the moving direction of the human body, process the moving direction of the human body and return to Step 1.

10. A method for identifying the moving direction of a human body based on a one-dimensional Fresnel array according to claim 9, characterized in that, In Step 4, processing the moving direction of the human body includes controlling the voice IC to perform voice broadcast.

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