Multiband infrared signal modulation and decoding method and system

Abstract

The invention relates to the field of optical control, in particular to a multi-band infrared signal modulation and decoding method and system, and the method comprises the steps: carrying out the frequency synchronization processing of infrared signals on each group of infrared intrusion detectors through a preset communication protocol, distributing corresponding signal communication frequencies for each group of infrared intrusion detectors, and carrying out the decoding of the infrared signals through the corresponding signal communication frequencies. Generating a corresponding infrared signal based on the signal communication frequency, and performing composite modulation on the infrared signal according to a preset composite modulation algorithm so as to emit a composite modulation signal through an emitter of an infrared correlation detector and receive the infrared signal through a receiver of the infrared correlation detector, and performing signal decoding on the composite modulation signal by using a corresponding demodulation algorithm.

Description

Technical Field

[0001] This invention relates to the field of optical control, specifically to a method and system for modulation and decoding multi-band infrared signals. Background Technology

[0002] Infrared beam detectors, as core equipment in perimeter security, work by using an infrared beam barrier formed between a transmitter and a receiver to detect intrusion. A typical structure consists of a pair of transmitters and receivers. The transmitter continuously emits an infrared beam, while the receiver monitors the beam's on / off state in real time. When the beam is blocked, an alarm signal is triggered. They are widely used for detecting unauthorized intrusions around buildings, walls, doors, and windows. Existing technologies have led to the mainstream solution of fixed-frequency, multi-beam collaborative detection. For example, a series of products launched by Hikvision uses a four-beam design, forming a three-dimensional protective network through multiple infrared beams; a series of products from Aotes uses a composite mode of upper and lower dual detection areas, generating an alarm only when both areas are triggered simultaneously, to reduce false alarms caused by interference from small animals or single light sources. To improve anti-interference capabilities, the industry generally adopts modulation technology improvements, using specific frequency pulse modulation to eliminate external noise interference such as sunlight and vehicle lights, and utilizing special conductive filters to block stray light and radio frequency interference, specifically optimizing false alarm problems in scenarios such as automotive headlight reflection.

[0003] However, existing infrared beam detectors still have many problems in practical applications, which seriously affect their monitoring accuracy and reliability, as follows: 1. Using a single filter material cannot block most interference from other light sources, making the receiver susceptible to external stray light and causing false alarms. 2. Equipped with a small lens, the light focusing and receiving effects are poor, the light receiver is unstable, and the beam angle is too large, making it susceptible to interference from non-target objects; 3. Using low-power infrared transmitters and receivers results in low transmission power, poor anti-interference capability in harsh environments such as fog, rain, and sandstorms, and signal transmission is easily interrupted. 4. Using a fixed frequency makes it impossible to handle interference from adjacent multiple beams and interference from ambient light at the same frequency, resulting in reduced equipment stability. 5. Using a single modulation method, the modulation waveform may overlap with the ambient light waveform, further increasing the possibility of false alarms. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for modulation and decoding of multi-band infrared signals, which can solve the problems in the prior art.

[0005] This invention is achieved through the following technical solution: This invention provides a method for modulation and decoding multi-band infrared signals, comprising: The infrared signals of each group of infrared beam detectors are synchronized using a preset communication protocol, so as to allocate the corresponding signal communication frequency to each group of infrared beam detectors. Based on the signal communication frequency, a corresponding infrared signal is generated, and the infrared signal is compositely modulated so as to transmit the composite modulated signal through the transmitter of the infrared beam detector. The infrared signal is received by the receiver of the infrared beam detector, and the composite modulation signal is decoded using a corresponding demodulation algorithm.

[0006] The present invention provides a modulation and decoding system for multi-band infrared signals, used to implement the modulation and decoding method for multi-band infrared signals as described in any one of the first aspects. The system consists of multiple sets of infrared beam detectors, each set of infrared beam detectors including a transmitter and a receiver.

[0007] In summary, the beneficial effects of this invention are: 1. The composite filter assembly significantly improves the blocking ability against interference from other light sources by using multiple layers of filters with different functions, thus reducing false alarms from the light receiver. 2. The large-size optimized lens enhances the light-gathering and light-receiving effects, reduces the beam angle, makes the light receiver more stable, and reduces interference from non-target objects.

[0008] 3. The combination of high-power infrared emitting tube and high-sensitivity infrared receiving tube improves the transmission power and reception performance, enhances the anti-interference ability in harsh environments, and ensures stable signal transmission. 4. The adaptive frequency adjustment system can dynamically avoid interference from adjacent multi-beams and ambient light interference at the same frequency, thus improving the stability of the equipment operation. 5. The composite modulation method gives the modulation waveform a uniqueness, reduces the risk of overlap with the ambient light waveform, and further reduces false alarms.

[0009] 6. The occlusion recognition system can accurately identify the uniqueness of beam occlusion and the time of occlusion, which improves the accuracy of judging real intrusion behavior and reduces the false judgment rate. Attached Figure Description

[0010] For ease of explanation, the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0011] Figure 1 This is a schematic diagram illustrating the steps of a multi-band infrared signal modulation and decoding method according to the present invention; Figure 2This is a schematic diagram of the working process of each group of infrared beam detectors in a multi-band infrared signal modulation and decoding system of the present invention. Figure 3 This is a schematic diagram of the transmitter's operation in the infrared beam detector of a multi-band infrared signal modulation and decoding system according to the present invention. Figure 4 This is a schematic diagram of the working process of the receiver in the infrared beam detector of the multi-band infrared signal modulation and decoding system of the present invention. Detailed Implementation

[0012] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0013] The following is combined with Figure 1-4 The present invention will be described in detail below.

[0014] like Figure 1 As shown, the present invention provides a method for modulation and decoding of multi-band infrared signals, comprising: S1: The infrared signals of each group of infrared beam detectors are synchronized through a preset communication protocol to allocate corresponding signal communication frequencies to each group of infrared beam detectors. S2: Generate a corresponding infrared signal based on the signal communication frequency, and perform composite modulation on the infrared signal according to a preset composite modulation algorithm, so as to transmit the composite modulated signal through the transmitter of the infrared beam detector; S3: Receive the infrared signal through the receiver of the infrared beam detector, and decode the composite modulation signal using a corresponding demodulation algorithm.

[0015] By using a preset communication protocol, the expected signal frequency adjustment time and corresponding signal communication frequency are generated for each group of infrared beam detectors. If different groups of infrared beam detectors use the same or similar frequencies for signal transmission, mutual interference is likely to occur, leading to signal reception errors or loss. By assigning different signal communication frequencies to each group of detectors, this interference can be effectively avoided, ensuring that each detector can transmit signals independently and accurately. The preset communication protocol will assign appropriate frequencies to each group of detectors based on factors such as detector layout and working environment, realizing the rational use of frequency resources and improving the efficiency of the entire system. By assigning different signal communication frequencies to different groups of detectors, signal interference between adjacent detectors is effectively avoided, improving the system's anti-interference capability, enabling the detectors to work stably in complex environments, and reducing false alarms and missed alarms.

[0016] Coordinated communication is conducted among the groups of infrared beam detectors to synchronize and correct their signal frequency adjustment times. Since individual detectors may have clock errors or be affected by other factors, failure to synchronize signal frequency adjustment times could lead to some detectors adjusting their frequencies at different times, resulting in signal confusion or interference during the adjustment process. Coordinated communication and synchronization correction ensure that all detectors adjust their frequencies at the same time, avoiding this problem. By synchronizing the signal frequency adjustment times, the synchronicity of all detectors during the frequency adjustment process is ensured, preventing signal confusion and interference caused by asynchronous frequency adjustments, thus improving the system's reliability and stability.

[0017] When the time meets the signal frequency adjustment time, the transmitter and receiver are adjusted to the signal communication frequency by the frequency adjustment module installed in the transmitter and receiver. When the time reaches the preset signal frequency adjustment time, the transmitter and receiver are adjusted to the specified signal communication frequency by the frequency adjustment module, thereby achieving the purpose of allocating the corresponding frequency to each group of detectors, enabling the detectors to transmit and receive signals according to the predetermined frequency. The preset communication protocol can reasonably allocate frequency resources according to the actual situation of the detectors, so that the frequency resources are fully utilized and the efficiency and performance of the entire system are improved.

[0018] Based on the signal communication frequencies previously allocated to each group of infrared beam detectors, corresponding infrared signals are generated. This process converts the allocated frequency information into specific infrared light signals. The frequency characteristics of these signals are consistent with the allocated signal communication frequencies, ensuring that the transmitted infrared signals match the allocated signal communication frequencies. This allows the receiver to accurately identify the signals. Different groups of detectors use different frequencies to avoid mutual interference and ensure that each detector operates independently and stably. Generating signals according to the frequencies allocated in accordance with the preset communication protocol is the foundation for the orderly operation of the entire system. It conforms to the communication rules designed for the system, enabling signals to be transmitted within the specified frequency range.

[0019] A pre-defined composite modulation algorithm is determined. This algorithm typically includes pulse width modulation (PWM) achieved through a pre-set pulse width sequence and phase modulation (PM) achieved through a pre-set phase change pattern. A single modulation method has a limited capacity to carry information. Composite modulation algorithms combine pulse width modulation and phase modulation, allowing information to be carried on the same signal simultaneously through pulse width and phase changes. This significantly increases the signal's information carrying capacity, enabling the transmission of more data. Different modulation methods have varying resistance to different types of interference. Composite modulation combines the advantages of multiple modulation methods, enabling better resistance to interference in complex environments and improving the reliability of signal transmission.

[0020] The generated infrared signal is pulse-width modulated according to a pre-set pulse width sequence, that is, the width of the pulses in the infrared signal is changed so that the pulse width carries additional information, thereby increasing the amount of data contained in the signal. The change of pulse width can be used as an encoding method to encode different information into the pulse width. The receiver can decode the corresponding information by detecting the change of pulse width, so as to realize the effective transmission of data. Different pulse widths can represent different signal states, such as logic "0" and logic "1", which facilitates the expression and processing of information in digital communication.

[0021] Based on a pre-set phase change pattern, phase modulation is applied to the infrared signal after pulse width modulation (PWM). By changing the signal phase, more information is embedded into the signal. Building upon pulse width modulation, phase modulation can carry additional information in the signal phase, further increasing the signal's information capacity. Phase modulation also exhibits good resistance to certain types of interference. In complex electromagnetic environments, phase changes are relatively stable, reducing the impact of interference on the signal and ensuring its accuracy.

[0022] The composite modulated signal, after pulse width modulation and phase modulation, is transmitted through the transmitter of the infrared beam detector. The signal after composite modulation contains more information and has better anti-interference ability. By transmitting the composite modulated signal through the transmitter, the receiver can receive the encoded and modulated signal, thereby realizing the effective transmission of information.

[0023] The receiver of the infrared beam detector turns on its light-receiving end and waits to receive the composite modulated infrared signal emitted by the transmitter. During the reception process, the receiver uses its front-end optical components (such as composite filter components, large-size lenses, etc.) to perform preliminary signal processing to enhance the signal reception effect.

[0024] The main function of a receiver is to receive signals sent by a transmitter. This is the foundation of the entire signal transmission and decoding process. Only after receiving the signal can subsequent processing and decoding operations be performed to obtain the information sent by the transmitter. Front-end optical components (such as composite filter components, large-size lenses, etc.) can help the receiver receive signals better. Composite filter components can filter out interference light such as visible light and ultraviolet light, allowing only the required infrared light to pass through. Large-size lenses can reduce the beam angle, making light reception more stable and improving the signal reception intensity and accuracy.

[0025] The received signal is filtered to remove noise and interference. This can be achieved through hardware filters (such as bandpass filters) or software filtering algorithms, allowing only signals within a specific frequency range to pass through, thereby improving signal quality. Since the signal will attenuate during transmission, the filtered signal needs to be amplified to achieve an appropriate amplitude so that subsequent demodulation operations can be performed accurately.

[0026] During signal transmission, interference from the external environment, such as electromagnetic interference and stray light, is inevitable. These interferences introduce noise into the signal. Filtering can remove this noise, improve the purity of the signal, and make subsequent demodulation operations more accurate. Signals will attenuate to some extent during transmission. If the signal strength is too low, it will affect the accuracy of demodulation. Amplification can enhance the signal to a suitable amplitude to ensure that subsequent demodulation circuits or algorithms can work properly.

[0027] According to a pre-set phase change pattern, the pre-processed signal is demodulated. By analyzing the phase information of the signal, some of the encoded information it carries is extracted. This usually requires a dedicated phase detection circuit or algorithm to convert the phase change of the signal into a digital signal for further processing. In composite modulation, phase modulation carries some important information. Through phase demodulation, this information can be extracted to provide the necessary data for subsequent signal decoding. Different phase changes represent different encoded information. By accurately detecting phase changes, the relevant data transmitted by the transmitter can be reconstructed.

[0028] After phase demodulation is completed, the signal is pulse-width demodulated according to the pre-set pulse width sequence. The width of the pulse in the signal is detected and converted into the corresponding digital code, thereby extracting the information carried by the pulse width modulation. Pulse width modulation is also an important part of composite modulation. It also carries a lot of information. By detecting the width of the pulse in the signal and converting it into digital code through pulse width demodulation, this information can be obtained and the data required for signal decoding can be further improved.

[0029] The information obtained from phase demodulation and pulse width demodulation is integrated and decoded according to preset encoding rules to restore the original data sent by the transmitter. This step requires logical analysis and processing of the demodulated digital signal to convert it into meaningful information, such as alarm signals and status information. The information obtained from phase demodulation and pulse width demodulation is a scattered and encoded digital signal, which needs to be integrated and decoded to restore the original data sent by the transmitter. This step is the final goal of the entire signal processing process. Only by completing decoding and integration can meaningful information be obtained and the purpose of signal transmission be achieved.

[0030] In one embodiment of the present invention, the step of performing frequency synchronization processing of infrared signals on each group of infrared beam detectors through a preset communication protocol, so as to allocate corresponding signal communication frequencies to each group of infrared beam detectors, includes: S11: Generate the expected signal frequency adjustment time and corresponding signal communication frequency for each group of infrared beam detectors through a preset communication protocol. S12: Coordinate the signal frequency adjustment time of each group of infrared beam detectors to synchronize and correct the signal frequency adjustment time of each group of infrared beam detectors. S13: When the time matches the signal frequency adjustment time, the transmitter and receiver are adjusted to the signal communication frequency by the frequency adjustment module installed in the transmitter and receiver.

[0031] The communication protocol first collects relevant information about each group of infrared beam detectors, such as their location, layout, and operating environment. This information forms the basis for subsequent frequency allocation and timing. Based on the collected information, combined with the overall frequency resources of the system and potential interference, the protocol analyzes the signal communication frequency requirements of each group of detectors. For example, adjacent detectors may need to be allocated different frequencies to avoid interference. Based on the analysis results, the protocol generates the expected signal frequency adjustment time and corresponding signal communication frequency for each group of infrared beam detectors. This process takes into account factors such as the system's operating rules and interference at different times to ensure the rationality and effectiveness of frequency allocation.

[0032] If different groups of infrared beam detectors use the same or similar frequencies for signal transmission, mutual interference can easily occur, leading to signal reception errors or loss. By assigning different signal communication frequencies to each group of detectors, this interference can be effectively avoided, ensuring that each detector can transmit signals independently and accurately. The preset communication protocol allocates appropriate frequencies to each group of detectors based on factors such as detector layout and operating environment, achieving rational utilization of frequency resources and improving the efficiency of the entire system. Furthermore, setting the expected signal frequency adjustment time allows the system to adjust the frequency according to actual conditions at different times, further optimizing the use of frequency resources.

[0033] Communication links are established between the various groups of infrared beam detectors to exchange information on signal frequency adjustment time. This can be achieved through wired or wireless communication, ensuring that the detectors can transmit adjustment time information to each other. The detectors exchange their expected signal frequency adjustment times, so that each detector knows the timing of other detectors. Based on the exchanged information, the signal frequency adjustment times of all detectors are synchronously corrected. This involves fine-tuning the time to ensure that all detectors adjust their frequencies at the same time, avoiding signal interference or confusion caused by time differences.

[0034] Since individual detectors may have clock errors or other factors, if the signal frequency adjustment time is not synchronized, some detectors will adjust their frequencies at different times, resulting in signal confusion or interference during the adjustment process. Through coordinated communication and synchronization correction, it can be ensured that all detectors adjust their frequencies at the same time, avoiding this problem. Synchronized frequency adjustment can make the entire system operate more stably, reduce signal loss or misjudgment caused by asynchronous frequency adjustment, and improve the reliability and stability of the system.

[0035] The transmitter and receiver continuously monitor the current time to determine whether the preset signal frequency adjustment time has been reached. When the time is detected to be in accordance with the signal frequency adjustment time, the frequency adjustment module in the transmitter and receiver is triggered. The frequency adjustment module adjusts the operating frequency of the transmitter and receiver according to the pre-allocated signal communication frequency, so that they switch to the new frequency for signal transmission and reception.

[0036] When the preset signal frequency adjustment time is reached, the transmitter and receiver are adjusted to the specified signal communication frequency by the frequency adjustment module, thereby achieving the purpose of allocating the corresponding frequency to each group of detectors, so that the detectors can transmit and receive signals according to the predetermined frequency. At different times, the system's working environment may change, such as the surrounding electromagnetic interference, the usage of other equipment, etc. By periodically adjusting the frequency, the detectors can adapt to these environmental changes and ensure the quality and stability of signal transmission.

[0037] In one embodiment of the present invention, the construction step of the communication protocol includes: S101: Obtain the relative setting information of each group of infrared beam detectors in order to construct a digital layout model of each group of infrared beam detectors. S102: Based on the selectable frequency channel range of each group of infrared beam detectors, deploy multiple selectable frequency forms for each group of infrared beam detectors within the digital layout model; S103: Based on the digital layout model, simulate the interference between adjacent beams of each group of infrared beam detectors for various candidate frequency forms, and obtain the interference characteristics between various candidate frequency forms of each group of infrared beam detectors. S104: The interference characteristics between various candidate frequency forms of each group of infrared beam detectors are used as the basis for evaluating the value of the collaborative work of each group of infrared beam detectors, and the communication protocol is constructed.

[0038] Using sensors, measuring tools, or manual input, relative setting information such as the installation position, angle, and orientation of each group of infrared beam detectors is collected. This information can be obtained through on-site measurement, the positioning function of the equipment itself, or system recording. Based on the collected relative setting information, a digital layout model is constructed using computer software or algorithms. In the model, each infrared beam detector is represented by a virtual object, and its position, angle, and other attributes correspond to the actual situation, thus intuitively presenting the spatial layout relationship of all detectors.

[0039] By constructing a digital layout model, the relative settings of each group of infrared beam detectors can be presented in an intuitive way. This helps with subsequent analysis and simulation work, enabling developers to better understand the spatial distribution of detectors and providing a foundation for frequency allocation and interference simulation. The digital layout model is an operable virtual model that allows for easy setting and adjustment of various parameters, providing a unified platform for subsequent frequency deployment and interference simulation, thus improving work efficiency and accuracy.

[0040] Consult the technical specifications or relevant documents of the infrared beam detectors to determine the range of available frequency channels for each group of detectors. This range is usually limited by the detector hardware performance and relevant standards. In a digital layout model, multiple different candidate frequency combinations can be assigned to each group of infrared beam detectors. These combinations can be used to try different frequency combinations for each detector to cover all possible frequency usage scenarios.

[0041] Different frequency combinations will have different effects on interference between detectors. Deploying multiple candidate frequency forms for each group of detectors can cover all possible frequency usage scenarios, ensuring that the optimal frequency allocation scheme can be found in subsequent simulations and evaluations, avoiding the omission of some potential available frequency combinations. The deployment of multiple candidate frequency forms can increase the flexibility of the system, enabling the system to adjust frequencies according to actual conditions. When some frequencies are interfered with or fail, other backup frequencies can be switched in a timely manner to ensure the normal operation of the system.

[0042] In the digital layout model, simulation parameters are set, such as the propagation characteristics of the infrared beam and the receiving sensitivity of the detector. These parameters can be set according to actual physical laws and detector performance. For each combination of candidate frequency forms, the beam propagation and interaction between infrared beam detectors are simulated. By calculating and analyzing parameters such as beam intensity and phase, it is determined whether there is interference between adjacent beams, and the degree and frequency of interference are recorded. The simulation results are organized and analyzed to summarize the interference characteristics between various candidate frequency forms, such as which frequency combinations are prone to interference and the relationship between interference intensity and frequency.

[0043] Before actually installing and using infrared beam detectors, simulating the interference between adjacent beams can predict the degree of interference between detectors under different frequency combinations. This helps to identify potential problems in advance and take corresponding measures to optimize them, avoiding false alarms or missed alarms caused by signal interference in actual use. By analyzing the interference characteristics, we can understand which frequency combinations are prone to interference, thereby avoiding these combinations when allocating frequencies and selecting frequencies with less interference for signal transmission, thus improving the system's anti-interference capability and stability.

[0044] Based on interference characteristics, the value of each candidate frequency combination is evaluated. Frequency combinations with lower interference levels have higher value for coordinated operation; conversely, frequency combinations with severe interference have lower value. Quantitative indicators, such as interference probability and interference intensity, can be used to measure the value of each frequency combination. Based on the value evaluation results, a communication protocol is developed. This protocol specifies parameters such as the signal communication frequency and signal frequency adjustment time that each group of infrared beam detectors should use to ensure coordinated operation between detectors, reduce interference, and improve system stability and reliability.

[0045] Using interference characteristics as a basis for evaluating the value of collaborative operation, a reasonable communication protocol can be formulated to ensure that each group of infrared beam detectors can work collaboratively at different frequencies, reducing mutual interference. The communication protocol specifies parameters such as the detector's operating frequency and frequency adjustment time, enabling the entire system to operate in an orderly manner. A reasonable communication protocol can optimize the utilization of frequency resources, improve the system's anti-interference capability and reliability, thereby enhancing the performance of the entire infrared beam detection system and providing more stable and accurate signal transmission and detection services for practical applications.

[0046] In one embodiment of the present invention, the communication protocol further includes ambient light elements. By sensing the ambient light conditions, corresponding ambient light elements are generated and introduced into the communication protocol. The communication protocol analyzes the interference characteristics between various candidate frequency forms of each group of infrared beam detectors under the current ambient light conditions based on the ambient light elements, so as to determine the signal communication frequency allocated to each group of infrared beam detectors. When the communication protocol includes ambient light elements, various ambient light conditions need to be introduced when performing adjacent beam interference simulation during the construction of the communication protocol, so as to simulate adjacent beam interference for each group of infrared beam detectors under various ambient light conditions.

[0047] Light sensors are deployed near each group of infrared beam detectors or at key locations in the system. These sensors can perceive information such as light intensity and spectral distribution in the environment in real time. The light sensors continuously collect ambient light data and transmit the data to the system's data processing module. The collected data includes light information under different time periods and weather conditions to comprehensively reflect changes in ambient light. Ambient light conditions are a dynamic factor; different times, weather, and geographical locations will all lead to differences in light conditions. By deploying light sensors to perceive ambient light in real time, the latest light information can be obtained, providing an accurate data foundation for subsequent analysis and decision-making. Collecting light data under different time periods and weather conditions allows for a comprehensive understanding of the changing patterns of ambient light, enabling the system to adapt to various complex environmental conditions.

[0048] The data processing module processes and analyzes the collected ambient light data, such as calculating the average and variance of light intensity and analyzing spectral characteristics. Based on the analysis results and the characteristics and requirements of the system, it generates corresponding ambient light elements. An ambient light element can be a comprehensive numerical value or a set of parameters used to quantify the degree of influence of ambient light on the infrared beam detector. The influence of ambient light on the infrared beam detector is complex. By generating ambient light elements, this influence can be quantified, facilitating unified processing and analysis in the communication protocol. Ambient light elements provide important decision-making basis for subsequent frequency allocation and interference analysis, enabling the system to make reasonable adjustments based on the actual ambient light conditions.

[0049] By incorporating the generated ambient light elements into the existing communication protocol, the protocol is updated and extended. This allows the communication protocol to adjust its frequency allocation and interference analysis strategies for the detector based on the ambient light elements. Traditional communication protocols do not consider the impact of ambient light. Introducing ambient light elements makes the communication protocol more flexible and adaptable to the actual environment. The protocol can automatically adjust its frequency allocation strategy according to changes in ambient light, improving the stability and reliability of the system. By combining ambient light elements, the communication protocol can better optimize the utilization of frequency resources, reduce the impact of ambient light interference on the detector, and thus improve the performance of the entire system.

[0050] When constructing the communication protocol, various different ambient light conditions are set in the digital layout model, such as bright sunlight, dim light on cloudy days, and nighttime. For each ambient light condition, adjacent beam interference is simulated for various candidate frequency forms of each group of infrared beam detectors. During the simulation, the influence of ambient light on the propagation of infrared beams and the reception of detectors is considered. For example, the scattering and reflection of ambient light will increase background noise and affect the detector's recognition of signals. The interference characteristics between various candidate frequency forms under different ambient light conditions are analyzed, and information such as the type, intensity, and probability of occurrence of interference are recorded.

[0051] In practical applications, ambient light can significantly affect the propagation of infrared beams and the reception of detectors. Introducing various ambient light conditions to simulate adjacent beam interference can more realistically reflect the working conditions of detectors in different environments, providing a more accurate basis for frequency allocation. Different ambient light conditions can cause different types of interference. Through simulation, some potential problems that are not easily detected under ideal conditions can be discovered, allowing for preventative measures to be taken in advance.

[0052] Based on the interference characteristic analysis results considering ambient light factors, a comprehensive evaluation of various candidate frequency forms is conducted. The evaluation considers not only the degree of interference but also the impact of ambient light on frequency stability. Based on the evaluation results, the signal communication frequency allocated to each group of infrared beam detectors under the current ambient light conditions is determined. This ensures that the detectors can operate stably and accurately in different environments. Determining the signal communication frequency based on the interference characteristic analysis results considering ambient light factors ensures that each group of infrared beam detectors can stably and accurately transmit and receive signals under the current ambient light conditions, reducing false alarms and missed alarms. Reasonable frequency allocation can effectively reduce the impact of ambient light interference on the system, improve the system's reliability and stability, and enable the system to operate normally in various complex environments.

[0053] In one embodiment of the present invention, the composite modulation algorithm performs composite modulation on the infrared signal by including pulse width modulation implemented by a pre-set pulse width sequence and phase modulation implemented by a pre-set phase change law.

[0054] Based on system design and communication requirements, a pre-set pulse width sequence is established. Each pulse width in this sequence corresponds to a specific information encoding, such as different binary data. The original infrared signal is generated based on the allocated signal communication frequency. This signal is a basic carrier signal with a fixed frequency and amplitude. The pulse width of the original infrared signal is adjusted according to the pre-set pulse width sequence. Within each signal period, the duration of the signal pulse is changed according to the corresponding pulse width value in the sequence, thereby encoding information into the pulse width. For example, if the current sequence value corresponds to a wider pulse width, the infrared signal pulse will be wider within that signal period; conversely, it will be narrower. After pulse width adjustment, a pulse width modulated infrared signal is obtained, carrying the information encoded by the pulse width.

[0055] A single infrared signal can only carry a limited amount of information. By using pulse width modulation (PWM), different information can be encoded into the pulse width. This allows each signal cycle to represent information not only by the presence or absence of a pulse, but also by the pulse width, thus greatly increasing the signal's information carrying capacity. The pulse width is relatively stable and not easily affected by common interference factors (such as slight electromagnetic interference or small fluctuations in ambient light). At the receiving end, as long as the change in pulse width can be accurately detected, the carried information can be correctly decoded, improving the reliability of signal transmission. The principle and implementation method of pulse width modulation are relatively simple, requiring only the adjustment of the signal's pulse width. This is relatively easy to implement in hardware and has a relatively low cost, making it suitable for large-scale applications.

[0056] Similarly, based on system design and communication requirements, a phase change pattern is pre-set. This pattern can be periodic, random, or generated by a specific algorithm. Different phase changes correspond to different information encodings. The infrared signal after pulse width modulation is used as the input signal, ready for phase modulation. According to the pre-set phase change pattern, the phase of the input signal is adjusted. Within each signal cycle, the phase of the signal is changed according to the pattern, thereby encoding additional information into the phase. For example, the phase of the signal is advanced in some cycles and delayed in others. After phase modulation, the final composite modulated signal is obtained. This signal contains information encoded by both pulse width modulation and phase modulation, and can be transmitted through the transmitter of the infrared beam detector.

[0057] By applying phase modulation to an existing pulse width modulation (PWM) signal, additional information can be carried on the same signal through phase changes. This further enhances the signal's information carrying capacity, enabling it to meet more complex communication needs. Phase modulation also possesses unique resistance to certain types of interference. For example, when interference related to signal amplitude is present, the phase information of a phase-modulated signal remains relatively stable and is less susceptible to influence. Combining PWM and phase modulation fully leverages the advantages of both modulation methods, improving the signal's anti-interference capability in complex environments. By simultaneously encoding information using both pulse width and phase in the signal, more data can be transmitted within the same timeframe, thereby increasing communication efficiency and reducing the time required for information transmission.

[0058] In one embodiment of the present invention, the method further includes continuously sensing the working environment of each group of infrared beam detectors to obtain ambient light intensity characteristics and temperature change trend characteristics; sequentially arranging and vectorizing the ambient light intensity characteristics and temperature change trend characteristics at each time point to generate an environmental sensing feature matrix; performing cluster analysis and correlation analysis based on the environmental sensing feature matrix to generate environmental impact factors according to the analysis results; and substituting the environmental impact factors into the composite modulation algorithm to adjust the composite modulation of the infrared signal accordingly.

[0059] Ambient light and temperature sensors are deployed near each group of infrared beam detectors to monitor the ambient light intensity and temperature of the detector's operating environment in real time. The sensors continuously collect ambient light intensity and temperature data, recording the values ​​at specific time intervals (e.g., per second, per minute). Ambient light intensity and temperature are crucial factors affecting the performance of the infrared beam detectors. Real-time monitoring of these environmental parameters allows for timely understanding of changes in the detector's environment, providing a basis for subsequent adjustments. Accurate environmental data is fundamental for feature extraction and analysis; only with reliable data can effective processing and decision-making be achieved.

[0060] The collected ambient light intensity and temperature data are processed to extract ambient light intensity features (such as average, maximum, minimum, and standard deviation) and temperature change trend features (such as the rate of temperature increase or decrease and the range of temperature fluctuation). The ambient light intensity features and temperature change trend features at each time point are arranged in chronological order to form an ordered sequence. The time-series arranged features are converted into vector form, with each vector representing the environmental feature information at a time point. These vectors are combined to generate an environmental perception feature matrix, where each row of the matrix corresponds to a time point and each column corresponds to a feature dimension.

[0061] Raw environmental data is usually large and complex. Directly processing this data increases computational complexity. By extracting features, the raw data can be simplified into representative features, reducing the amount of data and improving processing efficiency. The features are then arranged in time sequence and vectorized to form an environmental perception feature matrix, giving the data a structured form that facilitates subsequent clustering and correlation analysis.

[0062] Cluster analysis of the environmental perception feature matrix can be performed to divide time nodes with similar environmental features into different categories. Common clustering algorithms, such as K-means clustering, can be used to group data points based on the distance between feature vectors (such as Euclidean distance). The correlation between ambient light intensity features and temperature change trend features can be analyzed to determine the degree of their association. Correlation coefficients (such as Pearson correlation coefficient) can be used to measure the linear correlation between two features.

[0063] Cluster analysis can group similar environmental features together, helping to discover patterns and regularities under different environmental conditions. Correlation analysis can reveal the intrinsic relationship between ambient light intensity and temperature changes, providing theoretical support for understanding the impact of the environment on detectors. The analysis results provide important decision-making basis for generating environmental impact factors. By classifying and analyzing different environmental features, the degree of influence of the environment on infrared signal modulation can be assessed more accurately.

[0064] Based on the results of cluster analysis and correlation analysis, a comprehensive assessment of different categories of environmental characteristics is conducted, considering the impact of ambient light intensity and temperature changes on the signal transmission of the infrared beam detector. Based on the comprehensive assessment results, environmental impact factors are calculated. Environmental impact factors can be a single numerical value or a set of parameters used to quantify the influence of current environmental conditions on the composite modulation of infrared signals.

[0065] Environmental impact factors are a quantitative representation of the degree to which environmental conditions affect the modulation of infrared signals. By calculating environmental impact factors, complex environmental factors can be transformed into operable parameters, which are convenient for application in composite modulation algorithms. Environmental impact factors provide a unified standard for modulation adjustment under different environmental conditions, enabling the system to make reasonable adjustments automatically according to changes in the environment.

[0066] The generated environmental impact factors are substituted into the composite modulation algorithm. Based on the magnitude and direction of the environmental impact factors, relevant parameters in the algorithm are adjusted, such as pulse width sequence and phase change law. According to the adjusted composite modulation algorithm, the infrared signal is composite modulated so that the modulated signal can better adapt to the current environmental conditions.

[0067] Changes in environmental conditions can affect the transmission quality of infrared signals. For example, excessively strong ambient light can cause signal interference, and temperature changes can affect the sensitivity of the detector. By incorporating environmental factors into the composite modulation algorithm and adjusting the modulation parameters, the infrared signal can better adapt to different environmental conditions, improving the stability and reliability of signal transmission. Real-time adjustment of the composite modulation algorithm based on environmental changes can fully utilize the performance of the infrared beam detector, reduce false alarms and missed alarms, and improve the overall system performance and efficiency.

[0068] like Figure 2 As shown, the present invention provides a modulation and decoding system for multi-band infrared signals, used to implement the modulation and decoding method for multi-band infrared signals as described in any one of the first aspects. The system consists of multiple sets of infrared beam detectors, each set of infrared beam detectors including a transmitter and a receiver.

[0069] Preferably, the light-receiving end of the receiver is provided with a composite filter assembly, which includes a filter housing, a filter lens, and a filter receiving tube stacked in sequence. The filter housing is made of a material that can block visible light and ultraviolet light, and is used to filter visible light and ultraviolet light interference. The filter lens is made of a material with high transmittance that can only transmit infrared light, and is used to further filter the required infrared light. The filter receiving tube is made of a material with high transmittance for infrared light of a specific wavelength and high blocking of other wavelengths of light, and is used to further filter the required infrared light to pass through.

[0070] The filter housing is made of materials that can block visible and ultraviolet light. Common materials of this type have special molecular structures or contain specific additives, enabling them to absorb or reflect light in the visible and ultraviolet wavelength ranges. As the outermost layer of the composite filter assembly, the filter housing first performs preliminary filtering of incoming light. Visible and ultraviolet light are common sources of interference in the environment. Their presence can interfere with the reception of infrared signals, leading to receiver misjudgment or a decrease in the quality of the received signal. By blocking these interfering lights, the filter housing reduces stray light components in the light entering subsequent components, creating favorable conditions for subsequent fine filtering.

[0071] The filter lens uses a high-transmittance material that allows only infrared light to pass through. This material has excellent infrared light transmission properties, allowing as much infrared light as possible to pass through, while strongly blocking light of other wavelengths. It is made of special optical crystals or specially treated glass and other materials. After the initial filtering by the filter housing, the filter lens further filters the light. It can further block the remaining non-infrared light components in the light that has passed through the filter housing, allowing only infrared light to pass through. This makes the light entering the filter receiver tube purer, improving the purity and intensity of the signal, and helping the receiver to more accurately identify and process infrared signals.

[0072] The filter receiver tube uses a material with high transmittance for specific wavelengths of infrared light and high blocking power for other wavelengths. This material is precisely designed and manufactured to have extremely high transmittance for specific wavelengths of infrared light while almost completely blocking other wavelengths. It can be specifically optimized for the required infrared signal wavelength according to the system's needs. As the final filtering component of the composite filter assembly, the filter receiver tube performs the final screening of the incoming light. It can further filter out the small amount of non-specific wavelength infrared light present in the light passing through the filter lens, allowing only the specific wavelength of infrared light to reach the photosensitive element of the receiver. This ensures that the signal received by the receiver is an accurate and required infrared signal, greatly improving the accuracy and reliability of the signal.

[0073] Through multi-layer filtering, the composite filter assembly can effectively block interference sources such as visible light, ultraviolet light, and infrared light of non-specific wavelengths, significantly improving the receiver's anti-interference capability in complex lighting environments. Even under strong light or in the presence of a large amount of stray light, the receiver can accurately receive and process the required infrared signal. Multi-stage filtering makes the light entering the receiver purer, reducing the influence of noise and interference signals, thereby enhancing the quality of the infrared signal. This helps to improve the receiver's sensitivity and resolution, enabling the system to more accurately detect and identify target objects, and improving the performance and reliability of the entire infrared beam detection system. Different filter materials with different characteristics can be selected and the parameters of the filter assembly can be adjusted according to different application scenarios and needs to adapt to different wavelengths of infrared signals and different environmental conditions. This flexibility makes this technology have broad application prospects and can meet the infrared signal reception needs in various complex environments.

[0074] Preferably, both the transmitter and receiver of the transmitter are equipped with large-sized lenses. The lenses are made of optical-grade PMMA material with a diameter of 51mm. The curvature of the lenses adopts an aspherical structure to reduce the beam angle to within 5°, making the light reception more stable.

[0075] The lens is made of optical-grade PMMA. PMMA (polymethyl methacrylate) is a plastic with excellent optical properties, and optical-grade PMMA excels in transparency and refractive index. It has high transparency, allowing infrared light to pass through efficiently and reducing light loss during propagation. Simultaneously, its good optical uniformity ensures that light propagating within the lens does not produce significant distortion, guaranteeing the quality of the infrared beam. Using optical-grade PMMA to manufacture lenses results in relatively low cost, ease of processing into various shapes and sizes, and lighter weight compared to some traditional optical glass materials. This facilitates installation and maintenance in practical applications. Furthermore, it has good impact resistance, allowing it to withstand certain vibration and collision environments, ensuring the stability and reliability of the lens.

[0076] The lens features a large 51mm diameter design. This larger diameter means a larger light-transmitting area, allowing more infrared light to be emitted from the transmitter, increasing the propagation distance and intensity of the infrared signal. For the receiver, the larger light-receiving area allows for the collection of more infrared light, improving the receiver's sensitivity and enabling it to more accurately receive weak infrared signals. The large lens also has better light-gathering performance, concentrating the emitted infrared light into a single beam or more effectively focusing the received, scattered infrared light onto the receiver's photosensitive element, reducing light scattering and loss, thereby enhancing signal strength and stability.

[0077] The lens employs an aspherical curvature structure. Traditional spherical lenses are prone to aberrations during imaging, such as spherical aberration and coma. These aberrations lead to inaccurate light focusing and cause the beam to diverge. Aspherical lenses, through special curvature design, can effectively correct these aberrations, allowing light to be focused more accurately on a single point. In infrared signal transmission, this means the beam can be more tightly bound together, reducing the beam divergence angle. By precisely designing the curvature of the aspherical surface, the beam angle emitted by the transmitter can be reduced to within 5°. A smaller beam angle allows infrared light to propagate more concentratedly, reducing the light diffusion range and improving signal directionality and intensity. For the receiver, a more concentrated beam is easier to capture and receive, reducing the influence of external interference and thus making light reception more stable.

[0078] The large-size lens increases light transmission and focusing effect, while the aspherical structure reduces the beam angle. These factors work together to make the infrared signal emitted by the transmitter stronger and more concentrated, and the signal strength received by the receiver is correspondingly improved. The stronger signal is less susceptible to external interference during transmission, ensuring signal reliability. The smaller beam angle makes the infrared signal propagation range narrower, reducing interaction with other objects in the surrounding environment and reducing interference from stray light. At the same time, the lens's precise focusing effect allows the receiver to more accurately capture the target signal, avoiding misjudgment and interference caused by light scattering, thereby improving the stability and accuracy of light reception. In summary, the 51mm large-size aspherical lens made of optical-grade PMMA material on the transmitter and receiver is a carefully designed technical solution aimed at improving the transmission and reception performance of infrared signals and ensuring the stable operation of the entire infrared beam detection system.

[0079] Preferably, the transmitter is equipped with an infrared emitting tube with a chip size greater than 24mil and a transmission power greater than 250mW, and the receiver is equipped with an infrared receiving tube with a chip size greater than 90PD.

[0080] In semiconductor devices, chip size is an important indicator. A larger chip size means that more semiconductor material is used to generate and emit infrared light. The larger the chip size, the more light-emitting units (such as light-emitting diode structures) can be accommodated inside, which can more effectively convert electrical energy into infrared light. Infrared emitting diodes with a chip size greater than 24 mil can provide a larger light-emitting area, which makes the intensity of the emitted infrared light stronger and more uniformly distributed. Larger chips can withstand higher currents without being easily damaged, thus ensuring the stability and reliability of the emitting diode when operating at high power. This helps to improve the propagation distance and coverage of infrared signals, so that the signal can be transmitted to the receiver more effectively.

[0081] The transmission power directly determines the energy of the infrared light emitted by the infrared LED. Higher transmission power means that the infrared signal has stronger penetration ability and a longer propagation distance. In practical applications, when there are certain obstacles or environmental interference, high-power infrared signals can better overcome these adverse factors and ensure that the signal can accurately reach the receiver. In some complex environments, such as in the presence of smoke, dust or long-distance monitoring scenarios, infrared LEDs with a transmission power greater than 250mW are required to ensure effective signal transmission. For example, in the security monitoring system of a large warehouse, in order to cover a large area, high-power infrared LEDs are needed to ensure that the signal in every corner can be accurately received.

[0082] For infrared receiver tubes, the larger the chip size, the larger its photosensitive area. A larger photosensitive area means that more infrared light signals can be received, improving the receiver tube's sensitivity to weak signals. Infrared receiver tubes with chip sizes larger than 90PD can more effectively capture infrared signals from the transmitter. Even in the case of weak signals, they can accurately detect and convert them into electrical signals. Larger chip sizes can also improve the receiver tube's anti-interference ability. In complex electromagnetic environments, external interference signals can affect the reception of infrared signals. Larger chips can better collect and process infrared signals, reducing the impact of interference signals, thereby improving the accuracy and stability of reception.

[0083] The high-power, large-chip infrared emitting tube inside the transmitter and the large-chip infrared receiving tube inside the receiver work together to form a highly efficient infrared signal transmission and reception system. The transmitter emits a powerful and stable infrared signal, and the receiver can sensitively and accurately receive these signals, ensuring that the entire infrared beam detection system can work reliably under various environmental conditions. This improves the system's performance and reliability, and it is widely used in security monitoring, industrial inspection, smart homes and many other fields.

[0084] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any changes or substitutions conceived without creative effort should be included within the scope of protection of the invention.

Claims

1. A method for modulation and decoding multi-band infrared signals, characterized in that, include: The infrared signals of each group of infrared beam detectors are synchronized using a preset communication protocol, so as to allocate the corresponding signal communication frequency to each group of infrared beam detectors. Based on the signal communication frequency, a corresponding infrared signal is generated, and the infrared signal is compositely modulated so as to transmit the composite modulated signal through the transmitter of the infrared beam detector. The infrared signal is received by the receiver of the infrared beam detector, and the composite modulation signal is decoded using a corresponding demodulation algorithm.

2. The modulation and decoding method for multi-band infrared signals as described in claim 1, characterized in that, The steps for synchronizing the infrared signals of each group of infrared beam detectors using a preset communication protocol, and allocating corresponding signal communication frequencies to each group of infrared beam detectors, include: The preset communication protocol generates the expected signal frequency adjustment time and corresponding signal communication frequency for each group of infrared beam detectors. The signal frequency adjustment time of each group of infrared beam detectors is coordinated and communicated in order to synchronously correct the signal frequency adjustment time of each group of infrared beam detectors. When the time matches the signal frequency adjustment time, the transmitter and receiver are adjusted to the signal communication frequency by the frequency adjustment module installed in the transmitter and receiver.

3. The modulation and decoding method for multi-band infrared signals as described in claim 2, characterized in that, The steps for constructing the communication protocol include: Obtain the relative setting information of each group of infrared beam detectors in order to construct a digital layout model of each group of infrared beam detectors; Based on the selectable frequency channel range of each group of infrared beam detectors, multiple candidate frequency forms are deployed for each group of infrared beam detectors within the digital layout model; Based on the digital layout model, adjacent beam interference simulation is performed on various candidate frequency forms of each group of infrared beam detectors to obtain the interference characteristics between various candidate frequency forms of each group of infrared beam detectors. The interference characteristics among various candidate frequency forms of each group of infrared beam detectors are used as the basis for evaluating the value of the collaborative work of each group of infrared beam detectors, and the communication protocol is constructed accordingly.

4. The modulation and decoding method for multi-band infrared signals as described in claim 3, characterized in that, The communication protocol also includes ambient light elements. By sensing the ambient light conditions, corresponding ambient light elements are generated and introduced into the communication protocol. The communication protocol analyzes the interference characteristics between various candidate frequency forms of each group of infrared beam detectors under the current ambient light conditions based on the ambient light elements, so as to determine the signal communication frequency allocated to each group of infrared beam detectors. When the communication protocol includes ambient light elements, various ambient light conditions need to be introduced when performing adjacent beam interference simulation during the construction of the communication protocol, so as to simulate adjacent beam interference for each group of infrared beam detectors under various ambient light conditions.

5. The modulation and decoding method for multi-band infrared signals as described in claim 1, characterized in that, The infrared signal is compositely modulated by the composite modulation algorithm, which includes pulse width modulation achieved by a pre-set pulse width sequence and phase modulation achieved by a pre-set phase change law.

6. The modulation and decoding method for multi-band infrared signals as described in claim 5, characterized in that, It also includes continuously sensing the working environment of each group of infrared beam detectors to obtain ambient light intensity characteristics and temperature change trend characteristics; arranging and vectorizing the ambient light intensity characteristics and temperature change trend characteristics at each time point to generate an environmental sensing feature matrix; performing cluster analysis and correlation analysis based on the environmental sensing feature matrix to generate environmental impact factors according to the analysis results; and substituting the environmental impact factors into the composite modulation algorithm to make corresponding adjustments to the composite modulation of the infrared signal.

7. A modulation and decoding system for multi-band infrared signals, characterized in that, To implement the modulation and decoding method of multi-band infrared signals according to any one of claims 1-6, the system consists of multiple sets of infrared beam detectors, each set of infrared beam detectors including a transmitter and a receiver.

8. The modulation and decoding system for multi-band infrared signals as described in claim 7, characterized in that, The receiver's light-receiving end is equipped with a composite filter assembly, which includes a filter housing, a filter lens, and a filter receiving tube stacked sequentially. The filter housing is made of a material that can block visible light and ultraviolet light, used to filter visible light and ultraviolet light interference. The filter lens is made of a material with high transmittance that can only transmit infrared light, used to further filter the required infrared light. The filter receiving tube is made of a material with high transmittance for infrared light of a specific wavelength and high blocking of other wavelengths, used to further filter the required infrared light to pass through.

9. The modulation and decoding system for multi-band infrared signals as described in claim 7, characterized in that, Both the transmitter and receiver of the transmitter are equipped with large-sized lenses. The lenses are made of optical-grade PMMA material and have a diameter of 51mm. The curvature of the lenses adopts an aspherical structure to reduce the beam angle to within 5°, making the light reception more stable.

10. The modulation and decoding system for multi-band infrared signals as described in claim 7, characterized in that, The transmitter is equipped with an infrared emitting tube with a chip size greater than 24mil and a transmission power greater than 250mW, and the receiver is equipped with an infrared receiving tube with a chip size greater than 90PD.

Images