A smoke detection method, apparatus and medium

Abstract

The application discloses a smoke detection method and device and a medium, relates to the fire warning technical field, solves the problem of poor anti-interference ability of a smoke detection pulse signal, and has higher anti-interference ability through a chirp coding characteristic value fixed frequency pulse signal, widens the frequency spectrum range of a transmitted signal, improves the suppression ability to a single frequency interference, and obtains a maximum correlation value through correlation demodulation of a sampling digital signal and a chirp coding characteristic value, so that low-frequency interference signals are suppressed or reduced, thereby reducing a low-frequency interference background, improving the anti-interference ability and a signal-to-noise ratio, and since the signal after correlation demodulation has eliminated some low-frequency interference noise signals, and frequency modulation of the signal also improves the anti-interference performance of the signal, which is favorable for reducing smoke false alarms caused by external environmental light or electromagnetic interference.

Description

Technical Field

[0001] This application relates to the field of fire early warning technology, and in particular to a smoke detection method, device and medium. Background Technology

[0002] Photoelectric smoke detectors are a common type of smoke detector. They use photoelectric technology to detect smoke and trigger an alarm when smoke is detected. Photoelectric smoke detectors typically consist of an infrared emitter and a photoelectric receiver. The infrared emitter emits light periodically using a fixed-frequency pulse signal. When smoke is present inside the smoke chamber, the photoelectric receiver receives the pulse signal due to light scattering. It compares the amplitude of the received signal with a set alarm threshold; if the signal amplitude exceeds the threshold, a smoke alarm is triggered.

[0003] In practical applications, smoke detectors are often installed in environments with complex AC ambient light interference. Due to the periodic repetition of the fixed-repetition-frequency pulse signal, interference signals may superimpose on the repetitive portion, leading to strong intermodulation or crosstalk interference. AC interference in the environment can easily be introduced into the received signal, causing it to contain interference components and increasing the probability of false alarms caused by interference.

[0004] Therefore, how to solve the problem of poor anti-interference capability of smoke detection pulse signals is a technical problem that urgently needs to be solved by those in the field. Summary of the Invention

[0005] The purpose of this application is to provide a smoke detection method, device, and medium to solve the problem of poor anti-interference capability of smoke detection pulse signals.

[0006] To solve the above-mentioned technical problems, this application provides a smoke detection method, comprising:

[0007] Obtain chirped encoding feature values;

[0008] According to the preset symbol transmission rate, the chirped encoding feature value is input to the transmitter tube driving circuit to drive the light-emitting tube to emit a detection light signal;

[0009] Acquire actual optical signals and convert them into sampled digital signals;

[0010] The maximum correlation value is obtained by performing correlation demodulation on the sampled digital signal and the chirped coding feature value;

[0011] The presence of smoke is determined based on the maximum correlation value.

[0012] On the other hand, in the above-mentioned smoke detection method, the chirp encoding feature value setting step includes:

[0013] Determine the start frequency, end frequency, and modulation time within a coding cycle;

[0014] A binary chirped code feature value is generated based on the start frequency, the end frequency, and the modulation time.

[0015] On the other hand, in the above-mentioned smoke detection method, the step of inputting the chirped code feature value to the transmitter drive circuit according to the preset symbol emission rate to drive the light-emitting diode to emit a detection light signal includes:

[0016] According to the preset symbol transmission rate, the binary chirped code feature value is sent to the transmitter tube drive circuit;

[0017] The chirped coding feature value is divided into a preset number of pulse periods;

[0018] A corresponding pulse modulation signal is generated within each pulse cycle;

[0019] The pulse modulation signal drives the LED to emit a detection light signal.

[0020] On the other hand, in the above-mentioned smoke detection method, the step of acquiring the actual optical signal and converting it into a sampled digital signal includes:

[0021] The photoelectric receiving device is controlled to collect the actual optical signal, and the sampled voltage signal is obtained;

[0022] The sampled voltage signal is converted from analog to digital according to a preset sampling rate to obtain a sampled digital signal.

[0023] On the other hand, in the above-mentioned smoke detection method, the step of performing correlation demodulation on the sampled digital signal and the chirped code feature value to obtain the maximum correlation value includes:

[0024] The original sequence is obtained based on the chirped encoding feature values;

[0025] A sampling sequence is obtained based on the sampled digital signal;

[0026] The original sequence and the sampled sequence are autocorrelation calculated according to the first formula to obtain the maximum correlation value;

[0027] The first formula is: R(τ)=∫[x(t)*y(t+τ)]dt;

[0028] Where t represents time; τ represents time delay, which is the length of time by which the signal is delayed or advanced by τ at the current time point t; x(t) represents the original sequence; y(t) represents the sampled sequence, and y(t+τ) represents the length of time by which y(t) is delayed or advanced by τ; R(τ) represents the correlation value of the correlation demodulation with time delay τ.

[0029] On the other hand, in the above-mentioned smoke detection method, obtaining the original sequence based on the chirp coding feature value includes:

[0030] The low-level portion of the chirped encoding feature value is replaced with - to obtain the original sequence.

[0031] On the other hand, in the above-mentioned smoke detection method, the step of determining whether smoke exists based on the maximum correlation value includes:

[0032] Determine whether the number of consecutive times the maximum correlation value exceeds the preset alarm threshold has reached the preset number;

[0033] If so, it is determined that smoke is present, and the alarm device is triggered.

[0034] To address the aforementioned technical problems, this application also provides a smoke detection device, comprising:

[0035] The acquisition module is used to acquire chirped coding feature values;

[0036] A light signal generation module is used to input the chirped encoding feature value to the transmitter tube driving circuit according to the preset symbol transmission rate, so as to drive the light-emitting tube to emit a detection light signal;

[0037] The acquisition module is used to acquire actual optical signals and convert them into sampled digital signals;

[0038] The correlation demodulation module is used to perform correlation demodulation on the sampled digital signal and the chirped coded feature value to obtain the maximum correlation value;

[0039] The judgment module is used to determine whether smoke exists based on the maximum correlation value.

[0040] To address the aforementioned technical problems, this application also provides a smoke detection device, comprising:

[0041] Memory, used to store computer programs;

[0042] A processor is used to implement the steps of the smoke detection method described above when executing the computer program.

[0043] To address the aforementioned technical problems, this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the smoke detection method described above.

[0044] The smoke detection method provided in this application obtains chirped code feature values; according to a preset symbol transmission rate, the chirped code feature values ​​are input to the transmitter tube driving circuit to drive the light-emitting tube to emit a detection light signal; the actual light signal is acquired and converted into a sampled digital signal; the sampled digital signal and the chirped code feature values ​​are correlated and demodulated to obtain the maximum correlation value; and the presence of smoke is determined based on the maximum correlation value. The chirped code feature values ​​have higher anti-interference capability than pulse signals with a fixed repetition frequency, broaden the spectrum range of the transmitted signal, and improve the suppression capability against single-frequency interference. Furthermore, by obtaining the maximum correlation value through correlation demodulation of the sampled digital signal and the chirped code feature values, low-frequency interference signals are suppressed or reduced, thereby reducing the low-frequency interference background and improving anti-interference capability and signal-to-noise ratio. Since the correlated demodulated signal has already eliminated some low-frequency interference noise signals, and the frequency conversion modulation of the signal also improves the anti-interference performance of the signal, it is beneficial to reduce false smoke alarms caused by external ambient light or electromagnetic interference.

[0045] In addition, this application also provides an apparatus and a medium that correspond to the above method and have the same effect. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A flowchart of a smoke detection method provided in an embodiment of this application;

[0048] Figure 2 This is a waveform diagram of a pulse modulation signal provided in an embodiment of this application;

[0049] Figure 3 This is a sampling diagram of a sampling voltage signal provided in an embodiment of this application;

[0050] Figure 4 A schematic diagram of a correlation demodulation sliding window provided in an embodiment of this application;

[0051] Figure 5 A structural diagram of a smoke detection device provided in an embodiment of this application;

[0052] Figure 6 This is a structural diagram of another smoke detection device provided in an embodiment of this application. Detailed Implementation

[0053] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0054] The core of this application is to provide a smoke detection method, device, and medium.

[0055] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] Smoke detection is a technology used to detect smoke or flames, aiming to detect fires early and take appropriate measures. It typically consists of a smoke detector, a control panel, and an alarm. When the smoke detector detects smoke or flames, it triggers the control panel, which then sounds an alarm via audible siren, flashing lights, and other alarm mechanisms.

[0057] Photoelectric smoke detectors typically consist of a photosensitive element and an optical reflective smoke chamber. When smoke enters the chamber, smoke particles scatter light, causing the photosensitive element to receive a weakened light signal. When the photosensitive element detects a specific change in light intensity, the alarm is triggered, emitting an audible alarm or flashing light. In existing photoelectric smoke detector technologies, a fixed-frequency pulse signal is typically used to drive a light-emitting diode (LED) to emit a signal. When smoke is present inside the chamber, due to the light scattering effect, this pulse signal is received and amplified by a photoelectric receiver, and finally, the amplitude is obtained through an ADC (Analog-to-Digital Converter). The signal amplitude is compared with a set alarm threshold; if the signal amplitude exceeds the threshold, a fire alarm is triggered.

[0058] A pulse signal with a fixed repetition frequency is generated by a timer peripheral of a dedicated hardware module or chip. Due to the periodic repetition of the pulse signal in time, the interference signal may be superimposed on the repetitive part, resulting in strong intermodulation or crosstalk interference.

[0059] Optoelectronic receivers receive pulse signals and low-frequency or co-frequency interference signals introduced from the environment and amplify them. During signal demodulation, the amplitude of the received pulse signal or the sum of the amplitudes of several pulse signals is usually used as the signal value. Due to the weak signal and insufficient anti-interference capability of the system, the signal-to-noise ratio is often insufficient and the resolution is low.

[0060] To address the aforementioned technical problems, embodiments of this application provide a smoke detection method. Figure 1 A flowchart of a smoke detection method provided in this application embodiment is shown below. Figure 1 As shown, it includes:

[0061] S11: Obtain the chirped coding feature value;

[0062] Chirp is a coded pulse technique belonging to the discipline of coded pulse technology in communications. It represents digital bits by changing the carrier frequency over time, thereby enabling data transmission and demodulation. This modulation method is widely used in radar, wireless communications, and audio equipment.

[0063] In this embodiment, the chirped coding feature value refers to a specific coded signal generated through some preset modulation parameters. This embodiment does not limit the method by which the chirped coding feature value is generated, such as MATLAB, Python, etc.

[0064] For example, a 48-bit chirped code feature value can be generated by encoding, where each feature value represents a symbol (the number of symbols can be set as needed): 07C73531C1F0.

[0065] Specifically, the chirped coding feature value is a binary coding sequence.

[0066] Chirp coding modulation offers several advantages: First, it provides a degree of interference resistance. Second, it features frequency spreading: Chirp signals have a large bandwidth in the frequency domain, making them somewhat immune to narrowband interference. Narrowband interference typically affects only a small portion of the entire spectrum, while chirp signals, through frequency spreading, are distributed over a wider frequency range, thus mitigating the impact of narrowband interference. Third, it suppresses aliasing interference: Chirp signals represent information through linearly varying frequencies, allowing the receiver to separate signals of different frequencies using specific signal processing algorithms. This capability makes chirp coding modulation effective even in the presence of multipath propagation or other aliasing interference, reducing its impact. Fourth, it exhibits transient time-domain characteristics: Chirp signals are continuously varying pulse sequences, meaning their time-domain characteristics are transient. This means that each point in time in a chirp signal has a unique frequency value, which can be used to distinguish and suppress interfering signals.

[0067] Therefore, by using chirped coding eigenvalues, the spectral range of the transmitted signal is broadened, and the ability to suppress single-frequency interference is improved.

[0068] S12: According to the preset symbol transmission rate, the chirped encoding feature value is input to the transmitter tube driving circuit to drive the light-emitting tube to emit a detection light signal;

[0069] Symbol transmission rate refers to the number of symbols (or bits) transmitted per unit time in a digital communication system. A symbol is the basic unit representing digital information, which can be a single bit (0 or 1) or a combination of multiple bits. Symbol transmission rate is usually expressed in baud, which is the number of symbols transmitted per second. For example, if 10 symbols are transmitted per second, the symbol transmission rate is 10 baud. It is important to note that symbol transmission rate and bit rate are not necessarily equal. Bit rate refers to the number of bits (the number of bits of information carried by a symbol) transmitted per unit time. In some modulation methods, a symbol can carry multiple bits of information, so the symbol transmission rate can be lower than the bit rate.

[0070] The driving signal for the transmitter tube driver circuit is typically a pulse-type signal. This signal is transmitted to the transmitter tube in the form of brief high or low level pulses to trigger or control its operating state. Based on the obtained chirp-coded characteristic values, a corresponding pulse signal is generated. This pulse signal is input as the raw pulse signal to the transmitter tube driver circuit to generate an optical signal. When the optical signal enters the air, smoke particles scatter light. The tiny particles in the smoke scatter some of the light, causing changes in the intensity of the transmitted light, and thus altering the waveform amplitude.

[0071] A transmitter driver circuit is a circuit used to control and drive a light-emitting diode (LED). It primarily activates the LED by controlling current or voltage, causing it to emit light. This embodiment does not limit the specific structure of the transmitter driver circuit; it only needs to be able to drive the LED to emit light through pulse signals. The LED mentioned in this embodiment can be a light-emitting diode (LED), a laser diode, etc.

[0072] S13: Acquire actual optical signals and convert them into sampled digital signals;

[0073] This embodiment uses a photosensitive photodetector to acquire the actual received optical signal. The actual optical signal mentioned here may be a detection optical signal superimposed with ambient interference light. Specifically, the photodetector receives the actual optical signal, obtains a sampled electrical signal, and performs analog-to-digital conversion on the sampled electrical signal to obtain a sampled digital signal. A photodetector is a device that converts optical signals into electrical signals and is commonly used in optical communication, remote sensing, and optical control. Converting the optical signal into a digital signal facilitates analysis.

[0074] S14: Perform correlation demodulation on the sampled digital signal and the chirped coded feature value to obtain the maximum correlation value;

[0075] S15: Determine whether smoke is present based on the maximum correlation value.

[0076] Correlation demodulation is a commonly used signal processing technique to reduce low-frequency interference background. Its basic principle is to suppress interference signals and extract the signal of interest (SIO) through correlation operations. In correlation demodulation, a known reference signal or template is first obtained. This reference signal is correlated with the received signal, and the SIO is extracted by calculating their similarity. During this process, low-frequency interference signals are suppressed or reduced, thus minimizing their impact on the SIO. In this embodiment, correlation operations are used to suppress interference signals and extract the SIO. In correlation demodulation, the maximum correlation value represents the degree of similarity or matching between two signals. The magnitude of the maximum correlation value indicates the similarity between the two signals; a larger value indicates a higher degree of matching. By performing correlation calculations on the sampled digital signal and chirped coded feature values, essentially calculating their autocorrelation function, obtaining correlation data, finding the point with the maximum correlation value, and determining the presence of smoke based on the maximum correlation value, the process is completed.

[0077] The smoke detection method provided in this embodiment acquires chirped code feature values; according to a preset symbol transmission rate, the chirped code feature values ​​are input to the transmitter tube driving circuit to drive the light-emitting tube to emit a detection light signal; the actual light signal is acquired and converted into a sampled digital signal; the sampled digital signal and the chirped code feature values ​​are correlated and demodulated to obtain the maximum correlation value; the presence of smoke is determined based on the maximum correlation value. The chirped code feature values ​​have higher anti-interference capability than pulse signals with a fixed repetition frequency, broaden the spectral range of the transmitted signal, and improve the suppression capability against single-frequency interference. Furthermore, by obtaining the maximum correlation value through correlation demodulation of the sampled digital signal and the chirped code feature values, low-frequency interference signals are suppressed or reduced, thereby reducing the low-frequency interference background and improving anti-interference capability and signal-to-noise ratio. Since the correlated demodulated signal has already eliminated some low-frequency interference noise signals, and the frequency conversion modulation of the signal also improves the anti-interference performance of the signal, it is beneficial to reduce false smoke alarms caused by external ambient light or electromagnetic interference.

[0078] In another embodiment, the chirp encoding feature value setting step in the above-described smoke detection method includes:

[0079] Determine the start frequency, end frequency, and modulation time within a coding cycle;

[0080] A binary chirped code feature value is generated based on the start frequency, the end frequency, and the modulation time.

[0081] In chirp coding and modulation, the modulation parameters are determined as follows: the start frequency, end frequency, and modulation time within a coding period are determined; the signal frequency range, i.e., the start and end frequencies, and the modulation duration are determined. A chirp signal is a signal whose frequency changes over time, transitioning linearly or non-linearly from the start frequency to the end frequency.

[0082] Specifically, a binary chirped code feature value is generated based on the start frequency, the end frequency, and the modulation time, including:

[0083] During the modulation time, a frequency signal between the start frequency and the end frequency is received, and a binary chirped code feature value is generated.

[0084] In another embodiment, the smoke detection method described above, wherein the step of inputting the chirped code feature value to the LED driving circuit according to a preset symbol emission rate to drive the LED to emit a detection light signal includes:

[0085] According to the preset symbol transmission rate, the binary chirped code feature value is sent to the transmitter tube drive circuit;

[0086] The chirped coding feature value is divided into a preset number of pulse periods;

[0087] A corresponding pulse modulation signal is generated within each pulse cycle;

[0088] The pulse modulation signal drives the LED to emit a detection light signal.

[0089] In this embodiment, the binary chirped code feature value is sent to the transmitter tube driver circuit according to a preset symbol transmission rate. An appropriate pulse modulation scheme, such as pulse amplitude modulation (PAM), pulse width modulation (PWM), or pulse position modulation (PPM), is selected in advance. Specifically, a pulse width modulation scheme is selected, and the chirped code feature value is divided into a preset number of pulse periods. The duration of each pulse period is determined according to the symbol transmission rate and the modulation scheme. A corresponding pulse modulation signal is generated within each pulse period, and the transmitter tube is driven to emit a detection light signal based on the pulse modulation signal. Specifically, the generated pulse modulation signal is connected to the transmitter tube driver circuit, typically through a level conversion circuit, a current amplifier, or other related circuits to complete signal processing and driving. This embodiment does not limit the specific circuit structure of the transmitter tube driver circuit; it can be set according to actual needs.

[0090] For example, the chirped code feature value is 0x07A7353E1C1F0 (represented in hexadecimal for ease of display); it is divided into N periods:

[0091] First period: The period is M1 code widths: a1 code elements are 0 and b1 code elements are 1;

[0092] Second period: The period is M2 code widths: a2 code elements are 0 and b2 code elements are 1;

[0093] The third period: the period is M3 code widths: a3 code elements are 0 and b3 code elements are 1;

[0094] Fourth period: The period is M4 code widths: a4 code elements are 0 and b4 code elements are 1;

[0095] ...

[0096] The Nth period: The period is Mn code widths: there are an code elements 0 and bn code elements 1;

[0097] Figure 2 A waveform diagram of a pulse modulation signal provided in an embodiment of this application ( Figure 2 (Only a portion of the waveform signal is displayed).

[0098] In addition, to avoid interference from ambient light, the preset symbol transmission rate is set to a range of several hundred kHz to megahertz, but it is not limited to this frequency range and can be adjusted according to the frequency of interference signals in actual applications.

[0099] The solution provided in this embodiment enables the LED of the driving LED circuit to transmit signals according to the chirped coding characteristic value. This results in higher anti-interference capability compared to pulse signals with a fixed repetition frequency, broadens the spectrum range of the transmitted signal, and improves the ability to suppress single-frequency interference.

[0100] In another embodiment, the above-described smoke detection method, wherein acquiring the actual optical signal and converting it into a sampled digital signal includes:

[0101] The photoelectric receiving device is controlled to collect the actual optical signal, and the sampled voltage signal is obtained;

[0102] The sampled voltage signal is converted from analog to digital according to a preset sampling rate to obtain a sampled digital signal.

[0103] The photoelectric receiving device mentioned in this embodiment is a device that converts optical signals into electrical signals. This embodiment does not limit the type of photoelectric receiving device to be selected; it can be selected according to actual needs. For example: photodiode: A photodiode is a semiconductor device that has the characteristic of converting optical signals into current signals. When light shines on a photodiode, photons excite electrons in the photosensitive material, generating current; photoelectric converter: A photoelectric converter is a photoelectric conversion element based on a transistor structure. It changes the number of charge carriers in the base region by light irradiation, thereby regulating the output current or voltage; photomultiplier tube: A photomultiplier tube is a very sensitive photoelectric conversion device that uses the photoelectric effect to convert optical signals into electronic signals and obtains extremely high gain through multi-stage multiplication effect.

[0104] In this embodiment, an actual optical signal is received by a photoelectric receiving device and converted into a sampled voltage signal. The sampled voltage signal is then sampled by an analog-to-digital converter (ADC). This embodiment selects a preset sampling rate to perform the analog-to-digital conversion on the sampled voltage signal to improve signal resolution. Specifically, the preset sampling rate is a multiple of the sampling rate; a multiple of the sampling rate means that the sampling frequency is at least twice the signal bandwidth to satisfy the Nyquist sampling theorem. Figure 3 This application provides a sampling diagram of a voltage signal, as shown in the embodiment of the present application. Figure 3 As shown, the preset sampling rate is four times the sampling rate, meaning one symbol will be sampled four times. After obtaining the sampled digital signal, further processing can be performed, such as filtering, denoising, and correction. This embodiment does not impose specific limitations on these processes.

[0105] In another embodiment, the smoke detection method described above, wherein the step of performing correlation demodulation on the sampled digital signal and the chirped encoded feature value to obtain the maximum correlation value includes:

[0106] The original sequence is obtained based on the chirped encoding feature values;

[0107] A sampling sequence is obtained based on the sampled digital signal;

[0108] The original sequence and the sampled sequence are autocorrelation calculated according to the first formula to obtain the maximum correlation value;

[0109] The first formula is: R(τ)=∫[x(t)*y(t+τ)]dt;

[0110] Where t represents time; τ represents time delay, which is the length of time by which the signal is delayed or advanced by τ at the current time point t; x(t) represents the original sequence; y(t) represents the sampled sequence, and y(t+τ) represents the length of time by which y(t) is delayed or advanced by τ; R(τ) represents the correlation value of the correlation demodulation with time delay τ.

[0111] In this embodiment, obtaining the original sequence based on the chirped coding feature value and the sampled sequence based on the sampled digital signal involves processing the data to facilitate correlation demodulation calculation, ensuring that the two signals are time-aligned, i.e., having the same sampling rate and number of sampling points. If there is a time offset or delay between the two sequences, the correlation demodulation calculation is performed by using one sequence as a fixed pattern and sliding that pattern across the other sequence to find the sliding position where the correlation or cross-correlation function reaches its maximum value, i.e., the optimal alignment between the two sequences.

[0112] Given an input signal x(t) and a delayed signal y(t+τ), this means multiplying the two signals and then integrating them. This integration corresponds to the correlation calculation between the signals, used to measure the correlation between signals x(t) and y(t+τ) under different time delays.

[0113] The calculation of the cross-correlation function can be viewed as a sliding window operation, which iterates through each time point in the sequence for calculation. Figure 4 A schematic diagram of a related demodulation sliding window provided in an embodiment of this application is shown below. Figure 4 As shown, the sampled sequence y(t) is sequentially shifted and accumulated with the original sequence x(t) according to the sliding window direction. After K sliding windows, the correlation value sequence is obtained. When the sliding window ends, the maximum correlation value (correlation peak) is obtained to complete the correlation demodulation. Furthermore, since the signal modulation frequency is much higher than the interference frequency, the signal transmission time is very short, and the amplitude of AC interference remains approximately constant during this transmission time.

[0114] In another embodiment, the smoke detection method described above, wherein obtaining the original sequence based on the chirp coding feature value includes:

[0115] The low-level portion of the chirped encoding feature value that is 0 is replaced with -1 to obtain the original sequence.

[0116] In this embodiment, the low-level portion of the chirped coding feature value that is 0 is replaced with -1 to cancel the background noise. When performing related calculations, the low-level sampled data with -1 is accumulated with the high-level sampled data, and the amplitude of the interference part is approximately subtracted, thus eliminating the background noise.

[0117] In another embodiment, the smoke detection method described above, wherein determining whether smoke is present based on the maximum correlation value, includes:

[0118] Determine whether the number of consecutive times the maximum correlation value exceeds the preset alarm threshold has reached the preset number;

[0119] If so, it is determined that smoke is present, and the alarm device is triggered.

[0120] During smoke detection, the maximum correlation value is compared with a preset alarm threshold. Typically, if the maximum correlation value exceeds the preset alarm threshold, smoke is considered potentially present. If multiple consecutive signal acquisitions and demodulations result in signal values ​​exceeding the preset alarm threshold, a corresponding smoke alarm will be triggered. This embodiment does not limit the alarm device's display, such as a buzzer or warning light. Because the correlated demodulated signal has already eliminated some low-frequency interference noise, and the frequency modulation of the signal also improves its anti-interference performance, it helps reduce false alarms from the detector caused by ambient light or electromagnetic interference during application.

[0121] The smoke detection method has been described in detail in the above embodiments. This application also provides embodiments corresponding to the smoke detection device. It should be noted that this application describes the embodiments of the device from two perspectives: one is based on the functional modules, and the other is based on the hardware.

[0122] From the perspective of functional modules Figure 5 This is a structural diagram of a smoke detection device provided in an embodiment of this application, as shown below. Figure 5 As shown, the smoke detection device includes:

[0123] Module 21 is used to obtain chirped coding feature values;

[0124] The optical signal generation module 22 is used to input the chirped encoding feature value to the transmitting tube driving circuit according to the preset symbol transmission rate, so as to drive the light-emitting tube to emit a detection optical signal;

[0125] Acquisition module 23 is used to acquire actual optical signals and convert them into sampled digital signals;

[0126] The correlation demodulation module 24 is used to perform correlation demodulation on the sampled digital signal and the chirped coded feature value to obtain the maximum correlation value;

[0127] The judgment module 25 is used to determine whether smoke exists based on the maximum correlation value.

[0128] The smoke detection device provided in this embodiment includes an acquisition module 21 for acquiring chirp-coded feature values; a light signal generation module 22 for generating an original pulse signal based on the chirp-coded feature values; a light signal generation module 22 for inputting the original pulse signal to the transmitter tube drive circuit to generate a detection light signal according to a preset symbol transmission rate; an acquisition module 23 for acquiring the actual light signal and converting it into a sampled digital signal; a correlation demodulation module 24 for performing correlation demodulation on the sampled digital signal and the original pulse signal to obtain a maximum correlation value; and a judgment module 26 for judging whether smoke exists based on the maximum correlation value. Chirped coding features offer higher anti-interference capabilities compared to pulse signals with fixed repetition rates, broadening the spectral range of the transmitted signal and improving the suppression of single-frequency interference. Furthermore, by performing correlation demodulation on the sampled digital signal and chirped coding features to obtain the maximum correlation value, low-frequency interference signals are suppressed or reduced, thereby reducing the low-frequency interference background and improving anti-interference capability and signal-to-noise ratio. Since the correlated demodulated signal has already eliminated some low-frequency interference noise signals, and the frequency conversion modulation of the signal also improves the anti-interference performance of the signal, it is beneficial to reduce false smoke alarms caused by external ambient light or electromagnetic interference.

[0129] Since the embodiments of the apparatus and the embodiments of the method correspond to each other, please refer to the description of the embodiments of the method for the embodiments of the apparatus, which will not be repeated here.

[0130] Figure 6 A structural diagram of another smoke detection device provided in the embodiments of this application is shown below. Figure 6 As shown, the smoke detection device includes: a memory 30 for storing computer programs;

[0131] The processor 31 is used to execute a computer program to implement the steps of the method for acquiring user operation habit information as described in the above embodiment (smoke detection method).

[0132] The smoke detection device provided in this embodiment may include, but is not limited to, a laptop computer or a desktop computer.

[0133] The processor 31 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 31 may be implemented using at least one hardware form selected from ARM (Advanced RISC Machines) processors, 51 microcontrollers, and microcontroller units (MCUs). The processor 31 may also include a main processor and a coprocessor. The main processor, also known as the Central Processing Unit (CPU), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 31 may integrate a Graphics Processing Unit (GPU), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor 31 may also include an Artificial Intelligence (AI) processor, which handles computational operations related to machine learning.

[0134] The memory 30 may include one or more computer-readable storage media, which may be non-transitory. The memory 30 may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory 30 is used to store at least the following computer program 301, which, after being loaded and executed by the processor 31, is capable of implementing the relevant steps of the smoke detection method disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory 30 may also include an operating system 302 and data 303, and the storage method may be temporary or permanent storage. The operating system 302 may include Windows, Unix, Linux, etc. The data 303 may include, but is not limited to, data involved in implementing the smoke detection method.

[0135] In some embodiments, the smoke detection device may further include a display screen 32, an input / output interface 33, a communication interface 34, a power supply 35, and a communication bus 36.

[0136] Those skilled in the art will understand that Figure 6 The structure shown does not constitute a limitation on the smoke detection device and may include more or fewer components than shown.

[0137] The smoke detection device provided in this application includes a memory and a processor. When the processor executes the program stored in the memory, it can implement the following method: a smoke detection method, which involves acquiring chirped code feature values; inputting the chirped code feature values ​​to the transmitter tube driving circuit according to a preset symbol transmission rate to drive the light-emitting tube to emit a detection light signal; acquiring the actual light signal and converting it into a sampled digital signal; performing correlation demodulation on the sampled digital signal and the chirped code feature values ​​to obtain the maximum correlation value; and determining whether smoke is present based on the maximum correlation value. The chirped code feature values ​​have higher anti-interference capability than pulse signals with a fixed repetition frequency, broaden the spectrum range of the transmitted signal, and improve the suppression capability against single-frequency interference. Furthermore, by performing correlation demodulation on the sampled digital signal and the chirped code feature values ​​to obtain the maximum correlation value, low-frequency interference signals are suppressed or reduced, thereby reducing the low-frequency interference background and improving anti-interference capability and signal-to-noise ratio. Since the signal after correlation demodulation has already eliminated some low-frequency interference noise signals, and the frequency modulation of the signal also improves the anti-interference performance of the signal, it is beneficial to reduce false smoke alarms caused by external ambient light or electromagnetic interference.

[0138] Finally, this application also provides an embodiment corresponding to a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps described in the above-described smoke detection method embodiment.

[0139] It is understood that if the methods in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0140] The computer-readable storage medium provided in this embodiment stores a computer program. When the processor executes the program, it can implement the following method: a smoke detection method, which involves acquiring chirped code feature values; inputting the chirped code feature values ​​to the transmitter tube driving circuit according to a preset symbol transmission rate to drive the light-emitting tube to emit a detection light signal; acquiring the actual light signal and converting it into a sampled digital signal; performing correlation demodulation on the sampled digital signal and the chirped code feature values ​​to obtain the maximum correlation value; and determining whether smoke is present based on the maximum correlation value. The chirped code feature values ​​have higher anti-interference capabilities than pulse signals with a fixed repetition frequency, broaden the spectral range of the transmitted signal, and improve the suppression capability against single-frequency interference. Furthermore, by performing correlation demodulation on the sampled digital signal and the chirped code feature values ​​to obtain the maximum correlation value, low-frequency interference signals are suppressed or reduced, thereby reducing the low-frequency interference background and improving anti-interference capability and signal-to-noise ratio. Since the signal after correlation demodulation has already eliminated some low-frequency interference noise signals, and the frequency conversion modulation of the signal also improves the anti-interference performance of the signal, it is beneficial to reduce false smoke alarms caused by external ambient light or electromagnetic interference.

[0141] The smoke detection method, apparatus, and medium provided in this application have been described in detail above. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0142] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A smoke detection method, characterized in that, include: Obtain chirped encoding feature values; According to the preset symbol transmission rate, the chirped encoding feature value is input to the transmitter tube driving circuit to drive the light-emitting tube to emit a detection light signal; Acquire actual optical signals and convert them into sampled digital signals; The maximum correlation value is obtained by performing correlation demodulation on the sampled digital signal and the chirped coding feature value. The maximum correlation value represents the degree of similarity or matching between the sampled digital signal and the chirped coding feature value. The presence of smoke is determined based on the maximum correlation value.

2. The smoke detection method according to claim 1, characterized in that, The chirped coding feature value setting step includes: Determine the start frequency, end frequency, and modulation time within a coding cycle; A binary chirped code feature value is generated based on the start frequency, the end frequency, and the modulation time.

3. The smoke detection method according to claim 2, characterized in that, The step of inputting the chirped encoding feature value to the transmitter tube driving circuit according to the preset symbol transmission rate to drive the light-emitting tube to emit a detection light signal includes: According to the preset symbol transmission rate, the binary chirped code feature value is sent to the transmitter tube drive circuit; The chirped coding feature value is divided into a preset number of pulse periods; A corresponding pulse modulation signal is generated within each pulse cycle; The pulse modulation signal drives the LED to emit a detection light signal.

4. The smoke detection method according to claim 1, characterized in that, The process of acquiring actual optical signals and converting them into sampled digital signals includes: The photoelectric receiving device is controlled to collect the actual optical signal, and the sampled voltage signal is obtained; The sampled voltage signal is converted from analog to digital according to a preset sampling rate to obtain a sampled digital signal.

5. The smoke detection method according to claim 1, characterized in that, The step of performing correlation demodulation on the sampled digital signal and the chirped coded feature value to obtain the maximum correlation value includes: The original sequence is obtained based on the chirped encoding feature values; A sampling sequence is obtained based on the sampled digital signal; The original sequence and the sampled sequence are autocorrelation calculated according to the first formula to obtain the maximum correlation value; The first formula is: R(τ)=∫[x(t)*y(t+τ)]dt; Where t represents time; τ represents time delay, which is the length of time by which the signal is delayed or advanced by τ at the current time point t; x(t) represents the original sequence; y(t) represents the sampled sequence, and y(t+τ) represents the length of time by which y(t) is delayed or advanced by τ; R(τ) represents the correlation value of the correlation demodulation with time delay τ.

6. The smoke detection method according to claim 5, characterized in that, Obtaining the original sequence based on the chirped encoding feature value includes: The low-level portion of the chirped encoding feature value that is 0 is replaced with -1 to obtain the original sequence.

7. The smoke detection method according to any one of claims 1 to 6, characterized in that, The step of determining whether smoke exists based on the maximum correlation value includes: Determine whether the number of consecutive times the maximum correlation value exceeds the preset alarm threshold has reached the preset number; If so, it is determined that smoke is present, and the alarm device is triggered.

8. A smoke detection device, characterized in that, include: The acquisition module is used to acquire chirped coding feature values; A light signal generation module is used to input the chirped encoding feature value to the transmitter tube driving circuit according to the preset symbol transmission rate, so as to drive the light-emitting tube to emit a detection light signal; The acquisition module is used to acquire actual optical signals and convert them into sampled digital signals; The correlation demodulation module is used to perform correlation demodulation on the sampled digital signal and the chirped coding feature value to obtain the maximum correlation value, wherein the maximum correlation value represents the degree of similarity or matching between the sampled digital signal and the chirped coding feature value; The judgment module is used to determine whether smoke exists based on the maximum correlation value.

9. A smoke detection device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the smoke detection method as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the smoke detection method as described in any one of claims 1 to 7.

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