Cooking safety control method and system based on microwave molecular motion detection

Abstract

The invention relates to a cooking safety control method and system based on microwave molecular motion detection, and the method comprises the steps: obtaining a microwave emission signal and a corresponding microwave reflection signal, and enabling the microwave emission signal to be emitted to a cooking pot on a kitchen range; calculating a difference frequency signal based on the microwave emission signal and the corresponding microwave reflection signal; performing band-pass filtering processing on the difference frequency signal based on a preset frequency band to obtain a first target signal; the preset frequency band is obtained based on the frequency shift characteristic of liquid molecules; based on the first target signal, analyzing the distribution condition of energy on a frequency spectrum to obtain a frequency spectrum entropy; based on the frequency spectrum entropy, the working states of the kitchen range and the range hood are controlled, the problem that the intelligent control degree of cooking safety is insufficient is solved, through analysis of the frequency spectrum entropy, the hysteresis quality that response can only be conducted after the temperature is too high or oil smoke is generated is avoided, timely intervention can be conducted at the beginning of risks, intelligent active prevention and control of the risks are achieved, and the safety of cooking is improved. And the use experience is improved.

Description

Technical Field

[0001] This application relates to the field of intelligent control technology, and in particular to a cooking safety control method and system based on microwave molecular motion detection. Background Technology

[0002] As core appliances in modern kitchens, range hoods and cooktops are still in the early stages of intelligent development. Currently, the intelligent functions of mainstream kitchen appliances mainly focus on Wi-Fi network control, contactless gesture switches, and basic air quality monitoring, without exploring proactive safety protection mechanisms during the cooking process.

[0003] In practical use, users often become distracted, causing liquids in the pot to boil dry, potentially posing a fire hazard. Existing products rely heavily on temperature sensors or smoke detectors to sense the state inside the pot, but these technologies are significantly lagging and cannot provide timely warnings or interventions when risks first appear. Furthermore, even if the system detects an anomaly through temperature sensors or smoke detectors, it only provides an alarm notification; users usually still need to manually adjust the fan speed or turn off the device, failing to achieve true "autonomous driving" in the cooking field.

[0004] There is currently no effective solution to the problem of insufficient intelligent control over cooking safety in related technologies. Summary of the Invention

[0005] This embodiment provides a cooking safety control method and system based on microwave molecular motion detection to address the lack of intelligent control over cooking safety in related technologies.

[0006] In a first aspect, this embodiment provides a cooking safety control method based on microwave molecular motion detection, the method comprising:

[0007] Acquire microwave transmission signals and corresponding microwave reflection signals; the microwave transmission signals are used to direct the microwaves towards the cooking pot on the stove.

[0008] The difference frequency signal is calculated based on the microwave transmitted signal and the corresponding microwave reflected signal;

[0009] The difference frequency signal is bandpass filtered based on a preset frequency band to obtain the first target signal; the preset frequency band is obtained based on the frequency shift characteristics of liquid molecules.

[0010] Based on the first target signal, the distribution of energy in the spectrum is analyzed to obtain the spectral entropy;

[0011] The working status of the stove and range hood is controlled based on the spectrum entropy.

[0012] In some of these embodiments, the preset frequency band is 80-600Hz.

[0013] In some embodiments, based on the first target signal, the distribution of energy in the spectrum is analyzed to obtain the spectral entropy, including:

[0014] Calculate the first power spectral density corresponding to the first target signal;

[0015] The first power spectral density is normalized, and the spectral entropy is calculated based on the normalization result.

[0016] In some embodiments, controlling the operating state of the cooktop and range hood based on the spectral entropy includes:

[0017] If the spectral entropy is less than a preset first dry-burning threshold and the rate of change of the spectral entropy is greater than a second dry-burning threshold, then a dry-burning warning is triggered.

[0018] Based on the dry burning warning, the range hood's exhaust level is adjusted to the highest level, the stove's heating power is reduced by a preset amount, and the audible and visual alarm module is activated.

[0019] In some embodiments, after the dry-burning warning is triggered, the method further includes:

[0020] The spectrum entropy is continuously updated within a preset alarm time.

[0021] If the updated spectral entropy is greater than the third dry-burning threshold, then the cooktop and the range hood are controlled to return to the working state before the dry-burning warning was triggered; the third dry-burning threshold is greater than the first dry-burning threshold.

[0022] If the updated spectral entropy is less than the third dry-burning threshold, then the heat source of the stove is turned off.

[0023] In some embodiments, controlling the operating state of the cooktop and range hood based on the spectral entropy further includes:

[0024] If the spectral entropy is less than a preset first dry-burning threshold and the rate of change of the spectral entropy is less than a second dry-burning threshold, then it is determined whether the spectral entropy is less than a fourth dry-burning threshold; the fourth dry-burning threshold is less than the first dry-burning threshold.

[0025] If the spectral entropy is less than the fourth dry-burning threshold, then the stove and the range hood are controlled to enter standby mode;

[0026] If the spectral entropy is greater than the fourth dry-burning threshold, then the exhaust level of the range hood is adjusted to the lowest level.

[0027] In some embodiments, controlling the operating state of the cooktop and range hood based on the spectral entropy further includes:

[0028] If the spectral entropy is greater than a preset first dry-burning threshold and the rate of change of the spectral entropy is less than a second dry-burning threshold, then the centroid frequency of the corresponding power spectrum is calculated based on the first target signal.

[0029] A temperature prediction model is obtained by inputting the center of gravity frequency into the oil temperature prediction model to obtain the current oil temperature; the oil temperature prediction model is used to reflect the relationship between the oil temperature and the change of the center of gravity frequency.

[0030] Based on the current oil temperature, control the working status of the stove and the range hood.

[0031] In some embodiments, the method further includes:

[0032] The difference frequency signal is low-pass filtered from 0 to 5 kHz to obtain the second target signal;

[0033] Based on the second target signal, calculate the corresponding second power spectral density;

[0034] Based on the second power spectral density, the corresponding power spectral mean and power spectral standard deviation are calculated; based on the second power spectral density, the power spectral mean, and the power spectral standard deviation, the spectral kurtosis is calculated.

[0035] Based on the second power spectral density, the ratio of the total power in the high-frequency band to the total power in the low-frequency band is calculated to obtain the energy ratio.

[0036] If the spectral kurtosis is greater than the first fire threshold and the energy ratio is greater than the second fire threshold, then the stove and the range hood are controlled to be turned off.

[0037] Secondly, this embodiment provides an intelligent range hood and cooktop linkage system, the system including: a range hood, a cooktop, a microwave transceiver module, and a control module;

[0038] The range hood is installed opposite to the stove and is used to exhaust cooking fumes from the cooking environment.

[0039] The stove is used to heat cooking pots;

[0040] The microwave transceiver module is installed on the range hood and is used to transmit microwave signals to the cooking pot and receive microwave reflected signals reflected from the surface of the cooking pot.

[0041] The control module is connected to the range hood, the cooktop, and the microwave transceiver module, and is used to perform the steps of the method described in any one of the first aspects.

[0042] Thirdly, this embodiment provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in any one of the first aspects.

[0043] Compared with related technologies, the cooking safety control method and system based on microwave molecular motion detection provided in this embodiment acquires microwave emission signals and corresponding microwave reflection signals. The microwave emission signals are directed at the cooking pot on the stove. Based on the microwave emission signals and the corresponding microwave reflection signals, a difference frequency signal is calculated. The difference frequency signal is bandpass filtered based on a preset frequency band to obtain a first target signal. The preset frequency band is obtained based on the frequency shift characteristics of liquid molecules. Based on the first target signal, the energy distribution in the spectrum is analyzed to obtain the spectral entropy. Based on the spectral entropy, the working state of the stove and range hood is controlled. This solves the problem of insufficient intelligent control of cooking safety. By analyzing the spectral entropy, the lag in response after the temperature is too high or oil fumes are generated is avoided. Timely intervention can be carried out when risks first appear, realizing intelligent and proactive risk prevention and control, thereby improving the user experience.

[0044] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0045] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0046] Figure 1 This is a structural block diagram of the intelligent range hood and stove linkage system in the embodiments of this application;

[0047] Figure 2 This is a schematic flowchart of the cooking safety control method based on microwave molecular motion detection in the embodiments of this application;

[0048] Figure 3 This is a schematic diagram of an intelligent control process based on dry burning warning in one embodiment of this application;

[0049] Figure 4 This is a schematic diagram of an intelligent control process based on fire early warning in one embodiment of this application;

[0050] Figure 5 This is a schematic diagram of the intelligent range hood and stove linkage system in the embodiments of this application.

[0051] Reference numerals: 100, range hood; 110, smoke baffle; 200, cooktop; 300, microwave transceiver module; 400, control module; 500, cooking pot. Detailed Implementation

[0052] To better understand the purpose, technical solution, and advantages of this application, the application is described and explained below in conjunction with the accompanying drawings and embodiments.

[0053] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these” used in this application do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to these processes, methods, products, or devices. Words such as “connected,” “linked,” and “coupled” used in this application are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. Normally, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," "third," etc., used in this application are merely to distinguish similar objects and do not represent a specific order of objects.

[0054] This embodiment provides a cooking safety control method based on microwave molecular motion detection, which is applied in a kitchen setting, for example, to... Figure 1The intelligent range hood and cooktop linkage system shown includes: a range hood 100, a cooktop 200, a microwave transceiver module 300, and a control module 400. The range hood 100, installed opposite the cooktop 200, is used to exhaust cooking fumes from the cooking environment using a built-in fan. The cooktop 200 is used to heat a cooking pot 500. The microwave transceiver module 300, mounted on the range hood 100, transmits microwave signals to the cooking pot 500 on the cooktop 200 and receives microwave reflection signals from the surface of the cooking pot 500. The control module 400, connected to the range hood 100, cooktop 200, and microwave transceiver module 300, is used to execute the steps of a cooking safety control method based on microwave molecular motion detection. The control module 400 can be mounted on a computing terminal, or on the range hood 100 or the cooktop 200; this embodiment is not limited to these components.

[0055] Figure 2 This is a flowchart of the cooking safety control method based on microwave molecular motion detection in this embodiment. Figure 2 As shown, the method includes:

[0056] Step S210: Obtain the microwave transmission signal and the corresponding microwave reflection signal; the microwave transmission signal is used to direct the microwave to the cooking pot on the stove.

[0057] Specifically, the microwave transceiver module is used to generate and transmit microwave signals, and to receive corresponding microwave reflection signals. The microwave transceiver module is positioned above the cooktop, for example, mounted on a range hood, covering the cooking pots and pans in the cooking area. During cooking, the cooking pots and pans often contain liquid (water or oil). The microwave transmission signal is reflected by the liquid inside the cooking pot or by the dry-heated pot itself, resulting in the microwave reflection signal.

[0058] Step S220: Calculate the difference frequency signal based on the microwave transmitted signal and the corresponding microwave reflected signal.

[0059] Specifically, different reflective objects exhibit varying degrees of microwave reflection. This is due to factors such as molecular velocity (Doppler effect), structural micro-movements (e.g., rotation, vibration), or complex scattering (multipath, dispersion), causing the frequency of the reflected microwave signal to shift or become "disrupted" relative to the transmitted microwave signal. During normal cooking, liquid molecules within the cookware rotate at high speeds due to high temperatures or boiling, resulting in a frequency shift in the reflected signal. The reflected microwave signal often resembles a noisy broadcast, exhibiting a high spectral entropy. When the cookware is dry-heated, the absence of liquid molecules allows the cookware itself to directly interact with the transmitted microwave signal. This leads to a monotonous microwave reflection effect, with the frequency shift essentially disappearing, resulting in a quiet buzzing sound and a sharp drop in spectral entropy. Therefore, it is possible to first calculate the frequency shift between the transmitted and reflected microwave signals. Specifically, this involves mixing the transmitted and reflected microwave signals (multiplication) to obtain a mixed output. A low-pass filter is then used to remove high-frequency noise above 24Hz to eliminate interference from WiFi / Bluetooth signals, yielding the difference frequency signal. The frequency of the difference frequency signal is the Doppler frequency shift, which can be used to reflect the motion of liquid molecules.

[0060] Step S230: Bandpass filtering is performed on the difference frequency signal based on a preset frequency band to obtain the first target signal; the preset frequency band is obtained based on the frequency shift characteristics of liquid molecules.

[0061] Specifically, the rotational speed of water molecules is generally in the range of 0.5-3 m / s. Substituting this into the formula, we obtain the Doppler frequency shift formula:

[0062] ;

[0063] Among them, f d Indicates Doppler frequency shift, v r The radial velocity of the scatterer is represented by c (e.g., the projection of the tangential velocity of a water molecule's rotation), and c represents the speed of light (3 × 10⁻⁶). 8 From this, the effective frequency shift bandwidth of water can be obtained: 80-480Hz (the maximum and minimum velocities are substituted into the Doppler frequency shift formula to determine the effective signal range, which can cover the motion of water molecules). Oil, because its temperature is higher than water, has a relatively higher rotational speed (1.6-3 m / s), and its calculated frequency shift range is 250-600Hz. Based on this, a preset frequency band can be configured, for example, set to 80-600Hz, to cover commonly used liquids in cooking. Selective filtering can be achieved based on the frequency shift characteristics of liquid molecules, preserving key signals.

[0064] Step S240: Based on the first target signal, analyze the energy distribution in the spectrum to obtain the spectral entropy.

[0065] Specifically, because there are many moving liquid blobs inside the cooking pot, and different blobs have different velocities, the state cannot be directly characterized by a specific frequency shift, but it can be characterized by a spectral entropy value. A fast Fourier transform is performed on the first target signal to obtain the first power spectral density; the first power spectral density is normalized, and based on the normalization result, the spectral entropy H is calculated using the following formula:

[0066] ;

[0067] Where, p i This represents the first power spectral density after normalization.

[0068] Step S250: Based on the spectrum entropy, control the working status of the stove and range hood.

[0069] Specifically, when a liquid is heated, water molecules move violently, resulting in spectral broadening, increased disorder, and a rise in spectral entropy. Under the critical state of dry burning, water molecules gradually disappear, resulting in spectral peaks, decreased disorder, and a sharp drop in spectral entropy. Based on this, different entropy threshold ranges are set for different cooking states (including stillness, boiling, frying, and dry burning). According to the correspondence between the currently calculated spectral entropy and the entropy threshold range, the heat output of the stove, the airflow of the range hood, and its on / off status are adjusted accordingly. Furthermore, the spectral entropy H can be combined with the rate of change of spectral entropy ΔH / Δt to serve as the basis for adjusting the working state of the stove and range hood. For example, the classification of cooking state recognition features is shown in Table 1.

[0070] Table 1

[0071]

[0072] In this embodiment, a difference frequency signal is calculated based on the microwave transmission signal and the corresponding microwave reflection signal; the difference frequency signal is then bandpass filtered based on a preset frequency band to obtain a first target signal; the preset frequency band is obtained based on the frequency shift characteristics of liquid molecules; based on the first target signal, the energy distribution in the spectrum is analyzed to obtain the spectral entropy; based on the spectral entropy, the working status of the stove and range hood is controlled, solving the problem of insufficient intelligent control of cooking safety. By analyzing the spectral entropy, the fan and range hood can be automatically intervened in a timely manner when a risk first appears, avoiding the lag of needing manual control after the temperature is too high or oil fumes are generated, realizing intelligent and proactive risk prevention and control, thereby improving the user experience.

[0073] In some embodiments, for step S250, the operating states of the cooktop and range hood are controlled based on spectral entropy; see [link to relevant documentation]. Figure 3 Specifically, it includes the following steps:

[0074] Step S251: Determine whether the spectral entropy is less than the preset first dry-burning threshold and whether the rate of change of the spectral entropy is greater than the second dry-burning threshold.

[0075] Step S252: If the spectral entropy is less than the preset first dry burning threshold and the rate of change of the spectral entropy is greater than the second dry burning threshold, then a dry burning warning is triggered.

[0076] Step S253: Based on the dry burning warning, control the range hood to adjust its exhaust level to the highest level, control the stove to reduce its heating power by a preset amount (e.g., reduce by 30% or 100%), and control the sound and light alarm module to be turned on.

[0077] Specifically, in the rate of change of spectral entropy ΔH / Δt, Δt is a preset time interval, and ΔH is the change in spectral entropy before and after that time interval. The first dry-burning threshold characterizes the spectral entropy value of a narrow peak spectrum. The appearance of a narrow peak spectrum indicates weaker liquid molecule movement, resulting in a smaller frequency shift of the reflected signal relative to the transmitted signal. Preferably, the first dry-burning threshold is set to 3.2 bits. The second dry-burning threshold characterizes the rate of change of instantaneous spectral narrowing, which corresponds to the critical state of liquid drying out. Preferably, the second dry-burning threshold is set to 0.8 bits / s. After the dry-burning warning is triggered, the range hood operates at its highest exhaust setting, the stove's firepower decreases, and the audible and visual alarm module simultaneously alerts the user with an audible and visual alarm.

[0078] In this embodiment, by combining the first dry-burning threshold and the second dry-burning threshold, the abnormal state of dry burning is accurately identified, reducing the probability of misjudgment. This allows for timely response before the cookware temperature rises and smoke is generated, thereby improving the reliability of active protection.

[0079] In some of these embodiments, see Figure 3 After triggering the dry-burning warning, the following are also included:

[0080] Step S310: Continuously update the spectrum entropy within the preset alarm time.

[0081] Specifically, repeat steps S210 to S240 above to obtain the latest spectral entropy.

[0082] Step S320: If the updated spectral entropy is greater than the third dry-burning threshold (e.g., 4.0 bits), it indicates that the dry-burning danger has been eliminated. The cooktop and range hood are then restored to their operating state before the dry-burning warning was triggered, automatically returning to normal cooking conditions. The third dry-burning threshold is greater than the first dry-burning threshold; it characterizes the energy distribution during spectral broadening, indicating stronger movement of liquid molecules. If the updated spectral entropy is less than the third dry-burning threshold, it indicates that the dry-burning danger has not been eliminated. The heat source of the cooktop is then turned off to prevent further dry-burning.

[0083] In this application, the spectrum entropy is continuously updated to automatically identify whether the danger of dry burning has been eliminated, thereby making different responses to further improve the intelligent control of safe cooking and enhance the user experience.

[0084] In some of these embodiments, see Figure 3 The process includes the following steps after step S251:

[0085] Step S330: If the spectral entropy is less than the preset first dry-burning threshold and the rate of change of the spectral entropy is less than the second dry-burning threshold, then determine whether the spectral entropy is less than the fourth dry-burning threshold; the fourth dry-burning threshold is less than the first dry-burning threshold.

[0086] Specifically, the fourth dry-burning threshold is the spectral entropy value corresponding to a single-peak narrowband spectrum, used to distinguish whether the liquid in the cooking pot is cooling down or has already cooled down in a static state without cooking. Preferably, the fourth dry-burning threshold is set to 2.0 bits.

[0087] In step S340, if the spectrum entropy is less than the fourth dry-burning threshold, it indicates that no cooking is taking place and the temperature inside the cooking pot is low (e.g., close to room temperature), then the stove and range hood are controlled to enter standby mode; if the spectrum entropy is greater than the fourth dry-burning threshold, it indicates that no cooking is taking place and the cooking pot is cooling down, then the range hood's exhaust level is controlled to be adjusted to the lowest level.

[0088] In this embodiment, the fourth dry-burning threshold is used to further distinguish different states when not cooking, so as to finely control the application scenario with low oil smoke and low risk and enhance intelligence.

[0089] In some of these embodiments, see Figure 4 The process includes the following steps after step S251:

[0090] Step S410: If the spectral entropy is greater than the preset first dry burning threshold, or the rate of change of the spectral entropy is less than the second dry burning threshold, then the centroid frequency of the corresponding power spectrum is calculated based on the first target signal.

[0091] Specifically, the center of gravity frequency f mean The "centroid" position of the power spectrum P(f), i.e., the frequency range where the signal energy is mainly distributed, is essentially a weighted average value on the frequency axis, with the weights being f at each frequency point. i Power density P(f i The calculation formula is:

[0092] .

[0093] Step S420: Obtain the oil temperature prediction model by inputting the center of gravity frequency into the oil temperature prediction model to obtain the current oil temperature; the oil temperature prediction model is used to reflect the relationship between the oil temperature and the center of gravity frequency.

[0094] Specifically, the viscosity of liquids, especially oil, in cooking pots decreases as temperature rises, resulting in reduced molecular rotational resistance, increased velocity, and a greater average Doppler frequency shift. Based on this, a model representing the average Doppler frequency shift is established using the center-of-gravity frequency, thus creating an oil temperature prediction model. This model can be obtained by training a neural network model based on historical data or by fitting a quadratic function or other similar relationships.

[0095] In some of these embodiments, the oil temperature prediction model is expressed as follows:

[0096] ;

[0097] Where T represents the predicted current oil temperature, f mean The value represents the centroid frequency, and k1, k2, and k3 represent calibration coefficients, which are obtained by fitting historical data from the laboratory.

[0098] Step S430: Based on the current oil temperature, control the working status of the stove and range hood.

[0099] Specifically, if the current oil temperature is greater than the first temperature threshold T1 (e.g., 280℃), then it continues to determine whether the current oil temperature is greater than the second temperature threshold T2 (e.g., 300℃): if so, it indicates a high risk of fire, so the stove is controlled to reduce the firepower, a red alarm is triggered to remind the user that the oil temperature is too high, and the exhaust fan of the range hood is adjusted to the highest level; if not, a yellow alarm is triggered to remind the user that the oil temperature is too high, and the stove and range hood are not changed and continue to maintain their current working state.

[0100] If the current oil temperature is less than (or equal to) the first temperature threshold T1 (e.g., 280℃), assess the current cooking status and control the stove and range hood accordingly based on the classification of the cooking status. The classification method for the cooking status is shown in Table 1.

[0101] If H is greater than the third dry-burning threshold (e.g., 4.5 bits), the cooking state is determined to be boiling. Based on the boiling state, the heat source level of the stove is controlled to drop to the preset safe level, and the exhaust level of the range hood fan is controlled to be adjusted to the middle level.

[0102] If H∈[first dry burning threshold, third dry burning threshold], then the cooking state is determined to be frying state, and the exhaust level of the range hood fan is adjusted to the highest level based on the frying state.

[0103] If H∈[fourth dry burning threshold, first dry burning threshold), then the cooking state is determined to be a cooling state under static conditions, the stove is controlled to be in standby mode, and the exhaust level of the range hood fan is adjusted to the lowest level.

[0104] If H is less than the fourth dry-burning threshold, the cooking state is determined to be a static, non-cooking state. Based on the static, non-cooking state, the stove and range hood are controlled to be in standby mode.

[0105] If H is less than the first dry-burning threshold and ΔH / Δt is greater than the second dry-burning threshold, the cooking state is determined to be dry-burning, the stove is turned off immediately, and the range hood fan is adjusted to the maximum exhaust level.

[0106] In this embodiment, the problem of severe temperature lag in infrared sensors is overcome, improving the real-time performance of temperature data so as to detect abnormal oil temperatures in a timely manner and reduce the risk of fire.

[0107] In some embodiments, the cooking safety control method based on microwave molecular motion detection further includes:

[0108] Step S260: Perform low-pass filtering of the difference frequency signal from 0 to 5 kHz to obtain the second target signal; calculate the corresponding second power spectral density based on the second target signal.

[0109] Step S270: Based on the second power spectral density, calculate the corresponding power spectral mean and power spectral standard deviation; based on the second power spectral density, power spectral mean, and power spectral standard deviation, calculate the spectral kurtosis.

[0110] Specifically, the formula for calculating the spectral kurtosis K is as follows:

[0111] ;

[0112] Where μ is the N-frequency point f i The statistical mean (power spectrum mean), σ is the frequency point N f i Standard deviation (standard deviation of the rate spectrum), P(f i ) represents the second power spectral density.

[0113] Step S280: Based on the second power spectral density, calculate the ratio of the total power in the high-frequency band to the total power in the low-frequency band to obtain the energy ratio.

[0114] Specifically, taking 1kHz as the dividing line between the high-frequency and low-frequency bands as an example, the formula for calculating the energy ratio R is as follows:

[0115] ;

[0116] Where P(f) represents the second power spectral density.

[0117] Step S290: If the spectral kurtosis is greater than the first fire threshold and the energy ratio is greater than the second fire threshold, then control the stove and range hood to turn off.

[0118] For details, see Figure 4Because flames entering the cooking pot will generate high-frequency random scattering, the spectrum will contain non-Gaussian noise, with a relatively increased proportion of high frequencies. The kurtosis K corresponding to a Gaussian distribution is 3, which can be used to set a first fire threshold, for example, 5. When non-Gaussian noise (K>5) appears in the spectrum (1kHz-5kHz), to avoid misjudgment, the energy ratio is further checked to see if it is greater than a second fire threshold (preferably set to 0.2). If the energy ratio is also greater than the second fire threshold, it indicates a high fire risk. The stove's power / gas supply should be immediately cut off, a fire extinguishing warning should be issued, and the range hood fan should be turned off to prevent the range hood duct from catching fire.

[0119] In this embodiment, the spectral kurtosis is correlated with fire to improve the timeliness of fire warning, and the reliability of the results is verified by combining the energy ratio, thereby making a timely and accurate response and ensuring cooking safety.

[0120] This embodiment also provides an intelligent range hood and stove linkage system, such as Figure 1 The system shown includes: a range hood 100, a cooktop 200, a microwave transceiver module 300, and a control module 400. The range hood 100, installed opposite to the cooktop 200, is used to exhaust cooking fumes from the cooking environment; the cooktop 200 is used to heat a cooking pot 500; the microwave transceiver module 300, mounted on the range hood 100, is used to transmit microwave signals to the cooking pot 500 and receive microwave reflection signals reflected from the surface of the cooking pot 500; the control module 400, connected to the range hood 100, the cooktop 200, and the microwave transceiver module 300, is used to execute the steps of the cooking safety control method based on microwave molecular motion detection in any of the above embodiments.

[0121] In this embodiment, the control module calculates the difference frequency signal based on the microwave transmission signal and the corresponding microwave reflection signal; it performs bandpass filtering on the difference frequency signal based on a preset frequency band to obtain the first target signal; the preset frequency band is obtained based on the frequency shift characteristics of liquid molecules; based on the first target signal, it analyzes the energy distribution in the spectrum to obtain the spectrum entropy; based on the spectrum entropy, it controls the working status of the stove and range hood, solving the problem of insufficient intelligent control of cooking safety. By analyzing the spectrum entropy, the fan and range hood can be automatically intervened in time when a risk first appears, avoiding the lag of needing manual control after the temperature is too high or oil fumes are generated, realizing intelligent and proactive risk prevention and control, thereby improving the user experience.

[0122] The present embodiment will now be described and illustrated through preferred embodiments.

[0123] Figure 5 This is a schematic diagram illustrating an application scenario of this preferred embodiment. For example... Figure 5 As shown, the intelligent range hood and cooktop linkage system includes: a range hood 100, a cooktop 200, a microwave transceiver module 300, and a control module 400.

[0124] A range hood 100, installed opposite to a cooktop 200, is used to exhaust cooking fumes from the cooking environment. The cooktop 200 is used to heat a cooking pot 500. A microwave transceiver module 300, mounted on the baffle plate 110 of the range hood 100, is used to transmit microwave signals to the cooking pot 500 and receive microwave reflection signals from the surface of the cooking pot 500. A control module 400, connected to the range hood 100, the cooktop 200, and the microwave transceiver module 300, is used to execute the steps of a cooking safety control method based on microwave molecular motion detection.

[0125] like Figure 4 As shown, the cooking safety control method based on microwave molecular motion detection in this preferred embodiment includes the following steps:

[0126] S1. After the intelligent range hood and stove linkage system is turned on, the user can select the working mode, which includes intelligent mode and manual mode.

[0127] S2. After entering intelligent mode, control the microwave transceiver module 300 to start working.

[0128] S3. Obtain the microwave transmitted signal and the corresponding microwave reflected signal output by the microwave transceiver module 300. Calculate the difference frequency signal based on the microwave transmitted signal and the corresponding microwave reflected signal.

[0129] S4. Perform bandpass filtering on the difference frequency signal based on a preset frequency band to obtain the first target signal; the preset frequency band is 80-600Hz; based on the first target signal, analyze the energy distribution in the spectrum to obtain the spectral entropy H. Determine whether the spectral entropy H is less than the preset first dry-burning threshold (3.2 bits).

[0130] S5. If H < 3.2 bits, calculate the rate of change of the spectral entropy ΔH / Δt based on the spectral entropy H and the sampling interval Δt; determine whether the rate of change of the spectral entropy ΔH / Δt is greater than the second dry-burning threshold (0.8 bits / s). If H ≥ 3.2 bits, proceed to step S7.

[0131] S6. If H < 3.2 bits and ΔH / Δt > 0.8 bits / s, a dry-burning warning is triggered. Based on the dry-burning warning, the exhaust fan speed of the range hood 100 is adjusted to the highest level, and the heat source speed of the stove 200 is lowered to the preset safe level. If H < 3.2 bits and ΔH / Δt ≤ 0.8 bits / s, proceed to step S7.

[0132] S7. If H ≥ 3.2 bits or ΔH / Δt ≤ 0.8 bits / s, then calculate the centroid frequency f of the corresponding power spectrum based on the first target signal. meanObtain the oil temperature prediction model, input the center of gravity frequency into the oil temperature prediction model, and obtain the current oil temperature T.

[0133] S8. Determine whether the current oil temperature T is greater than the first temperature threshold T1 (280℃).

[0134] S9. If T > 280℃, determine whether the current oil temperature T is greater than the second temperature threshold T2 (300℃). If T > 300℃, it indicates a high fire risk. Control the stove 200 to reduce the firepower, and use a red alarm to remind the user that the oil temperature is too high. At the same time, control the range hood 100 to adjust the exhaust level to the highest setting. If T ≤ 300℃, use a yellow alarm to remind the user that the oil temperature is too high. Do not control the stove 200 and range hood 100, and continue to maintain their current operating status.

[0135] S10. If T≤280℃, then the cooking state is determined based on the spectral entropy H.

[0136] S11. Determine if the spectral entropy H is greater than 4.5 bits. If H > 4.5 bits, determine that the cooking state is boiling. Based on the boiling state, control the heat source level of the stove 200 to drop to the preset safe level, and control the exhaust level of the range hood 100 to adjust to the middle level.

[0137] S12. If H ≤ 4.5 bits, determine if the spectral entropy H is greater than 3.2 bits. If H ≤ 4.5 bits and H ≥ 3.2 bits, determine that the cooking state is frying / stir-frying, and adjust the exhaust level of the range hood 100 to the highest level based on the frying / stir-frying state. If H < 3.2 bits, determine if the spectral entropy H is greater than 2.0 bits.

[0138] S13. If H < 2.0 bit, the cooking state is determined to be a static, non-cooking state. Based on the static, non-cooking state, the cooktop 200 and range hood 100 are controlled to be in standby mode. If H < 3.2 bit and H ≥ 2.0 bit, the cooking state is determined to be a static, cooling state. The cooktop 200 is controlled to be in standby mode, and the exhaust level of the range hood 100 is adjusted to the lowest level.

[0139] After step S3, the following steps can be performed in parallel:

[0140] S14. Perform a low-pass filter of 0-5kHz on the difference frequency signal to obtain the second target signal; calculate the corresponding second power spectral density based on the second target signal.

[0141] S15. Based on the second power spectral density, calculate the corresponding power spectral mean and standard deviation; based on the second power spectral density, power spectral mean, and power spectral standard deviation, calculate the spectral kurtosis K. Based on the second power spectral density, calculate the ratio of the total power in the high-frequency band to the total power in the low-frequency band, and obtain the energy ratio R.

[0142] S16. If the spectral kurtosis K is greater than the first fire threshold (first fire threshold = 5) and the energy ratio R is greater than the second fire threshold (second fire threshold = 0.2), then control the stove 200 and the range hood 100 to turn off. The control priority of step S16 is higher than that of steps S6-S13.

[0143] In this preferred embodiment, the traditional lag in temperature / smoke detection is overcome, triggering an early warning 5-8 seconds before dry burning. The warning response time is ≤1 second, the false alarm rate is <3%, and multiple functions such as oil temperature estimation, cooking status recognition, and fire protection are simultaneously achieved. Furthermore, zero-contact detection is achieved, without relying on modifications to the cookware. This preferred embodiment improves the intelligent control of cooking safety, enables intelligent proactive risk prevention, and significantly enhances the user experience.

[0144] It should be noted that the steps shown in the above process or in the flowchart of the accompanying figures can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0145] Furthermore, in conjunction with the cooking safety control method based on microwave molecular motion detection provided in the above embodiments, this embodiment can also provide a storage medium for implementation. This storage medium stores a computer program; when executed by a processor, the computer program implements any of the cooking safety control methods based on microwave molecular motion detection in the above embodiments.

[0146] It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. All other embodiments derived by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0147] Obviously, the accompanying drawings are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar situations based on these drawings without any creative effort. Furthermore, it is understood that although the work done in this development process may be complex and lengthy, for those skilled in the art, certain design, manufacturing, or production modifications made based on the technical content disclosed in this application are merely conventional technical means and should not be considered as insufficient disclosure of this application.

[0148] The term "embodiment" in this application refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply that it is mutually exclusive with or independent of other embodiments. It will be clearly or implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0149] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A cooking safety control method based on microwave molecular motion detection, characterized in that, The method includes: Acquire microwave transmission signals and corresponding microwave reflection signals; the microwave transmission signals are used to direct the microwaves towards the cooking pot on the stove. The difference frequency signal is calculated based on the microwave transmitted signal and the corresponding microwave reflected signal; The difference frequency signal is bandpass filtered based on a preset frequency band to obtain the first target signal; the preset frequency band is obtained based on the frequency shift characteristics of liquid molecules. Based on the first target signal, the distribution of energy in the spectrum is analyzed to obtain the spectral entropy; The working status of the stove and range hood is controlled based on the spectrum entropy.

2. The cooking safety control method based on microwave molecular motion detection according to claim 1, characterized in that, The preset frequency band is 80-600Hz.

3. The cooking safety control method based on microwave molecular motion detection according to claim 1, characterized in that, Based on the first target signal, the energy distribution in the spectrum is analyzed to obtain the spectral entropy, including: Calculate the first power spectral density corresponding to the first target signal; The first power spectral density is normalized, and the spectral entropy is calculated based on the normalization result.

4. The cooking safety control method based on microwave molecular motion detection according to claim 1, characterized in that, Based on the spectral entropy, controlling the operating state of the stove and range hood includes: If the spectral entropy is less than a preset first dry-burning threshold and the rate of change of the spectral entropy is greater than a second dry-burning threshold, then a dry-burning warning is triggered. Based on the dry burning warning, the range hood's exhaust level is adjusted to the highest level, the stove's heating power is reduced by a preset amount, and the audible and visual alarm module is activated.

5. The cooking safety control method based on microwave molecular motion detection according to claim 4, characterized in that, After triggering the dry burning warning, the following is also included: The spectrum entropy is continuously updated within a preset alarm time. If the updated spectral entropy is greater than the third dry-burning threshold, then the cooktop and the range hood are controlled to return to the working state before the dry-burning warning was triggered; the third dry-burning threshold is greater than the first dry-burning threshold. If the updated spectral entropy is less than the third dry-burning threshold, then the heat source of the stove is turned off.

6. The cooking safety control method based on microwave molecular motion detection according to claim 4, characterized in that, Based on the spectral entropy, controlling the operating state of the stove and range hood further includes: If the spectral entropy is less than a preset first dry-burning threshold and the rate of change of the spectral entropy is less than a second dry-burning threshold, then it is determined whether the spectral entropy is less than a fourth dry-burning threshold; the fourth dry-burning threshold is less than the first dry-burning threshold. If the spectral entropy is less than the fourth dry-burning threshold, then the stove and the range hood are controlled to enter standby mode; If the spectral entropy is greater than the fourth dry-burning threshold, then the exhaust level of the range hood is adjusted to the lowest level.

7. The cooking safety control method based on microwave molecular motion detection according to claim 4, characterized in that, Based on the spectral entropy, controlling the operating state of the stove and range hood further includes: If the spectral entropy is greater than a preset first dry-burning threshold and the rate of change of the spectral entropy is less than a second dry-burning threshold, then the centroid frequency of the corresponding power spectrum is calculated based on the first target signal. A temperature prediction model is obtained by inputting the center of gravity frequency into the oil temperature prediction model to obtain the current oil temperature; the oil temperature prediction model is used to reflect the relationship between the oil temperature and the change of the center of gravity frequency. Based on the current oil temperature, control the working status of the stove and the range hood.

8. The cooking safety control method based on microwave molecular motion detection according to claim 1, characterized in that, The method further includes: The difference frequency signal is low-pass filtered from 0 to 5 kHz to obtain the second target signal; Based on the second target signal, calculate the corresponding second power spectral density; Based on the second power spectral density, the corresponding power spectral mean and power spectral standard deviation are calculated; based on the second power spectral density, the power spectral mean, and the power spectral standard deviation, the spectral kurtosis is calculated. Based on the second power spectral density, the ratio of the total power in the high-frequency band to the total power in the low-frequency band is calculated to obtain the energy ratio. If the spectral kurtosis is greater than the first fire threshold and the energy ratio is greater than the second fire threshold, then the stove and the range hood are controlled to be turned off.

9. An intelligent range hood and stove linkage system, characterized in that, The system includes: a range hood, a cooktop, a microwave transceiver module, and a control module; The range hood is installed opposite to the stove and is used to exhaust cooking fumes from the cooking environment. The stove is used to heat cooking pots; The microwave transceiver module is installed on the range hood and is used to transmit microwave signals to the cooking pot and receive microwave reflected signals reflected from the surface of the cooking pot. The control module is connected to the range hood, the cooktop, and the microwave transceiver module, and is used to execute the steps of the method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 8.

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