Visibility detection method and device

Abstract

The present invention belongs to the field of visibility monitoring, and in particular relates to a visibility detection method and device. The method first generates a variable coded pulse train based on an initial duty cycle preset in a visibility detection device and a discrete time-sharing coding control rule, and then obtains a multi-level variable coded pulse train through a signal power amplifier. Utilizing a hierarchical power control model and emission angle intervals, infrared signals of different light intensities and emission angles are cyclically excited in a target detection area. A signal receiving device collects scattered infrared signals in real time, and a filtering discrimination evaluation model is used in combination with multi-level variable coded pulse train information to determine whether an infrared signal of a corresponding power level exists. If so, the visibility of the target detection interval is obtained and updated in real time based on the infrared signal of the current power level and a preset signal power level-visibility mapping table. The method achieves efficient, real-time, and low-cost visibility monitoring through time-sharing coding and multi-level power control.

Description

Technical Field

[0001] The present invention belongs to the field of visibility monitoring, and in particular relates to a visibility detection method and device. Background Art

[0002] In the fields of transportation and meteorology, visibility detection is crucial to driving safety and weather forecasting. Low visibility environments will significantly increase the risk of traffic accidents, and the meteorological field requires accurate data to support weather forecasts and climate research. However, existing technologies have significant defects: First, they rely on high-cost hardware. For example, traditional laser scatterometers or transmission visibility meters require expensive optical components, and the cost of a single device is as high as tens of thousands of yuan, making it difficult to deploy on a large scale. Second, vision-based methods have poor environmental adaptability. For example, the Chinese patent with authorization announcement number CN110826412B provides a highway visibility detection system and method, and proposes a visibility calculation scheme based on lane line detection. Although visibility is estimated through lane line feature analysis, it relies on high-resolution cameras and deep profile feature processing hardware, which is expensive and fails on unstructured roads (such as no clear lane lines) or in bad weather (lane lines are covered with snow); for example, the Chinese patent with authorization announcement number CN110020642B The present invention provides a visibility recognition method based on vehicle detection, which adopts vehicle detection and trajectory tracking technology and requires a high-frame-rate camera to capture the target movement details. However, in scenarios with sparse traffic, the algorithm fails due to the lack of detection targets, and vehicle tracking is easily disturbed by rain and snow, causing trajectory breakage, and the visibility estimation error exceeds 30%. In addition, existing image detection methods generally rely on high-computing power models (such as deep learning), require cloud computing resource support, and are difficult to run in real time on low-cost edge devices. Moreover, most of the existing visibility detection technologies deploy high-precision detection devices and models at the detection end for detection. There are few methods that achieve low-cost, multi-node detection methods by improving the signal adjustment method at the transmitting end. For this reason, the present invention provides a visibility detection method and device. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention proposes a visibility detection method and device, which first generates a variable coded pulse string based on the initial duty cycle and discrete time-sharing coding control rules preset by the visibility detection device, and then obtains a multi-level variable coded pulse string through a signal power amplifier device; utilizes a hierarchical power control model and an emission angle interval to cyclically excite infrared signals of different light intensities and emission angles in the target detection area; collects scattered infrared signals in real time through a signal receiving device, and uses a filtering discrimination evaluation model combined with multi-level variable coded pulse string information to determine whether there is an infrared signal of the corresponding power level; if so, obtains the visibility of the target detection interval based on the current power level infrared signal and a preset signal power level-visibility mapping table and updates and displays it in real time; this method achieves efficient, real-time and low-cost visibility monitoring through time-sharing coding and multi-level power control.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A visibility detection method, comprising:

[0006] Based on the initial duty cycle preset by the visibility detection device and the preset discrete time-sharing coding control rule, a variable coded pulse train is generated;

[0007] Based on the variable coded pulse train, a multi-level variable coded pulse train is obtained through a signal power amplifier;

[0008] Based on the multi-level variable coded pulse train, a preset hierarchical power control model is combined with a preset emission angle interval to cyclically stimulate infrared signals of different light intensities and emission angles in the target detection area;

[0009] The signal receiving device configured in the visibility detection device collects the infrared signals scattered from the target detection area in real time, and uses a preset filtering and discrimination evaluation model to synchronously combine the multi-level variable coded pulse train information to match and judge whether there is an infrared signal of corresponding power level in the infrared signals collected from the target detection area;

[0010] If it exists, the current power level infrared signal obtained by detection is combined with the preset signal power level-visibility one-to-one mapping table to invert the visibility corresponding to the target detection area and update it in real time.

[0011] Specifically, the process of acquiring the multi-level variable coded pulse train includes:

[0012] Generate the reference clock pulse train sequence required by the visibility detection device through clock control at an excitation frequency of 38 kHz and a preset initial duty cycle;

[0013] Using a counter to measure the reference clock pulse train sequence, obtain the period length T corresponding to the reference clock signal and the high-level window width and the adjacent low-level window width in each period;

[0014] Based on the period length T corresponding to the reference clock signal and the high-level window width in each period, the standard duty cycle of the reference clock signal is obtained.

[0015] Specifically, the acquisition process of the multi-level variable coded pulse train also includes:

[0016] Preset the signal excitation instantaneous power level range and obtain the signal transmission information sequence corresponding to the maximum signal detection intensity detected in each historical visibility detection process;

[0017] Based on the signal excitation instantaneous power level interval and the corresponding average power threshold in the signal transmission information sequence, the upper and lower limits of the high-level window width corresponding to the reference clock pulse string, and the transmission angle interval, the duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation and the corresponding search constraints are constructed.

[0018] Specifically, the acquisition process of the multi-level variable coded pulse train also includes:

[0019] Based on the duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation and the corresponding search constraints, a multi-objective optimization discrimination algorithm and a two-way search rule are combined to search and solve the problem. The optimal duty cycle and optimal emission angle corresponding to the maximum probability of detecting the infrared signal at each instantaneous power level are obtained.

[0020] Based on the optimal duty cycle corresponding to each instantaneous power level and the reference clock pulse string, a multi-level variable coded pulse string is obtained and distinguished coding is marked, and decoding information corresponding to the distinguished coding is pre-stored in the signal receiving device.

[0021] Specifically, the process of bidirectional search rules includes:

[0022] Based on the upper and lower limits of the high-level window width and the instantaneous power level range of the signal excitation, the upper limit of the high-level window width corresponding to the standard duty cycle is used as the search starting point, and each high-level window width value is searched downward, and the duty cycle of the corresponding window width is obtained with each high-level window width;

[0023] At the same time, based on the duty cycle corresponding to each window width, a double search is performed from the lower limit to the upper limit of the signal excitation instantaneous power level interval and the emission angle interval, under the condition that the average power threshold corresponding to the emission pulse in a single cycle is met, to obtain each optimal duty cycle and the power level sequence that meets the average power threshold under each optimal duty cycle and the optimal emission angle corresponding to the maximum probability of the infrared signal being detected under the optimal duty cycle.

[0024] Specifically, the steps of obtaining the visibility corresponding to the target detection area include:

[0025] Based on a power level sequence that satisfies an average power threshold corresponding to each duty cycle, infrared rays corresponding to a power level sequence for each duty cycle are generated through the hierarchical power control model, and infrared rays of different power levels with distinguishing codes are cyclically emitted from high to low power levels at the optimal emission angle corresponding to the current duty cycle;

[0026] The signal receiving device configured based on each visibility detection device collects the corresponding target detection area signal in real time, and filters the real-time collected target detection area signal through a filtering algorithm combined with the marked distinction code and the decoding information corresponding to the distinction code, and at the same time determines whether the filtered target detection area collection signal contains an infrared ray signal with a distinction code.

[0027] Specifically, the step of obtaining the visibility corresponding to the target detection area further includes:

[0028] If it exists, the infrared ray signal information with the discriminative code obtained is input into the matching detection algorithm and combined with the signal power level-visibility mapping table to match the infrared ray signal with the discriminative code with the corresponding power level to obtain the visibility of the current target detection area corresponding to the matching level;

[0029] If it does not exist, the infrared ray signal at the power level corresponding to each duty cycle is transmitted, collected and detected and matched in a cyclic manner from high to low power levels until the visibility of the current target detection area is detected;

[0030] When the visibility detection device corresponding to the current interval detects the corresponding visibility, and at least one of the two adjacent visibility detection devices does not detect the corresponding visibility, the power level and duty cycle information corresponding to the current interval visibility are shared to the preset power level-visibility one-to-one mapping table of the adjacent visibility detection device that has not detected the visibility, and the emission priority of the infrared rays corresponding to the shared power level and duty cycle is set to the highest.

[0031] Specifically, the preset emission angle interval is ; The signal receiving device configured in the visibility detection device is a conical total reflection condenser.

[0032] A visibility detection device includes: a pulse train generation module, a power amplification module, and a signal excitation module;

[0033] The pulse train generating module generates a variable coded pulse train based on the initial duty cycle preset by the visibility detection device and the preset discrete time-sharing coding control rule;

[0034] The power amplification module obtains a multi-level variable coded pulse train based on the variable coded pulse train through a signal power amplifier;

[0035] The signal excitation module, based on the multi-level variable coded pulse train, cyclically excites infrared signals of different levels of light intensity and emission angles to the target detection area through a preset hierarchical power control model combined with a preset emission angle interval.

[0036] Specifically, the visibility detection device also includes a detection and discrimination module and a real-time display module;

[0037] The detection and discrimination module collects infrared signals scattered from the target detection area in real time through the signal receiving device configured by the visibility detection device, and uses a preset filtering and discrimination evaluation model to synchronously combine multi-level variable coded pulse train information to match and discriminate whether there is an infrared signal of corresponding power level in the infrared signals collected from the target detection area;

[0038] The real-time display module is used to inversely obtain the visibility corresponding to the target detection area based on the infrared signal of the current power level of the detected target detection area combined with a signal power level-visibility one-to-one mapping table.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] In response to the shortcomings of the existing technology, the present invention breaks through the limitations of existing visibility detection that relies on high-computing power models through innovative signal conditioning at the transmitter, and realizes real-time monitoring of low-cost edge devices. In particular, based on discrete time-sharing coding and multi-level power dynamic control, the matching relationship between high-level width and instantaneous power is optimized through bidirectional search at the transmitter, combined with dynamic adjustment of the emission angle gain, so that the infrared signal of a single node maintains a high signal-to-noise ratio in complex environments without relying on complex cloud-based algorithms; through the coded pulse train generation mechanism of the interval sequence of the visibility detection device, combined with the power level-duty cycle information sharing strategy between adjacent nodes, while ensuring that a single node only needs to process signals of limited power level, the dependence on a single high-precision sensor is reduced; in addition, based on the bidirectional search rule of the duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation, the emission angle gain factor and instantaneous power level can be dynamically optimized according to the real-time noise power spectrum density and the high-level window width, significantly improving the detection stability under low visibility conditions while reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a visibility detection method according to Example 1 of the present invention;

[0042] Figure 2 A logic architecture diagram of a visibility detection method for implementing the present invention;

[0043] Figure 3 A simplified diagram of the infrared ray emission angle of a visibility detection device according to embodiment 1 of the present invention;

[0044] Figure 4 This is a module diagram of a visibility detection device according to embodiment 2 of the present invention. DETAILED DESCRIPTION

[0045] Example 1

[0046] Existing visibility image detection methods generally rely on high-computing models and require cloud computing resources, making them difficult to run in real time on low-cost edge devices. In addition, most existing visibility detection technologies deploy expensive and high-precision detection devices and models at the detection end. Few of them improve the signal conditioning method at the transmitter to achieve low-cost, multi-node detection. This makes it difficult to deploy corresponding visibility detection devices in large quantities, reducing the visibility detection accuracy of the corresponding road sections. For this reason, please refer to Figure 1 and Figure 2 The present invention provides an embodiment of a visibility detection method, comprising the following steps:

[0047] S1. Generate a variable coded pulse train based on the initial duty cycle preset by the visibility detection device and a preset discrete time-sharing coding control rule;

[0048] S2. Based on the variable coded pulse train, obtain a multi-level variable coded pulse train through a signal power amplifier;

[0049] S3. Based on the multi-level variable coded pulse train, a preset hierarchical power control model is used in combination with a preset emission angle interval to cyclically excite infrared signals of different light intensities and emission angles in the target detection area;

[0050] Furthermore, the visibility detection device in this embodiment uses a fully digital CMOS logic circuit without a single-chip processor, so the corresponding anti-interference ability is extremely strong, and it can accurately generate pulse signals and cyclically change the intensity of the modulated emitted infrared rays.

[0051] S4. Using a signal receiving device configured in the visibility detection device, the infrared signal scattered from the target detection area is collected in real time. A preset filtering and discrimination evaluation model is used to synchronously combine the multi-level variable coded pulse train information to match and determine whether there is an infrared signal of a corresponding power level in the infrared signal collected from the target detection area.

[0052] Furthermore, the preset emission angle interval in this embodiment is , see Figure 3 This is a simplified diagram of the visibility detection device emitting infrared rays, where A is the emission angle, the two circles corresponding to 1 and 2 are the corresponding infrared signal emission ports, and Q represents the target detection area;

[0053] The signal receiving device configured in the visibility detection device is a conical total reflection condenser, which has a large amount of light entering and a small overall size of the equipment, greatly reducing the cost of use.

[0054] S5. If it exists, the visibility corresponding to the target detection area is obtained by inverting the infrared signal of the current power level obtained by detection and combining it with a preset signal power level-visibility one-to-one mapping table and updating and displaying it in real time.

[0055] Furthermore, in this embodiment, the process of acquiring the multi-level variable coded pulse train includes:

[0056] Generate the reference clock pulse train sequence required by the visibility detection device through clock control at an excitation frequency of 38 kHz and a preset initial duty cycle;

[0057] Using a counter to measure the reference clock pulse train sequence, obtain the period length T corresponding to the reference clock signal and the high-level window width and the adjacent low-level window width in each period;

[0058] Based on the period length T corresponding to the reference clock signal and the high-level window width in each period, the standard duty cycle of the reference clock signal is obtained.

[0059] Preset the signal excitation instantaneous power level range and obtain the signal transmission information sequence corresponding to the maximum signal detection intensity detected in each historical visibility detection process:

[0060] ,

[0061] in, It represents the instantaneous power corresponding to the pulse train transmitted by the nth visibility detection device at the current time t, Directly determines the emission intensity of the infrared signal. In low-visibility scenarios, aerosol scattering and dielectric absorption significantly weaken the signal strength. Therefore, it is necessary to increase the instantaneous power to penetrate environmental interference and ensure that the receiver can capture the valid echo signal. In this embodiment, by setting different power levels at different duty cycles, the probability of signal detection is increased while reducing the corresponding energy consumption. Indicates the duty cycle of the pulse train transmitted by the nth visibility detection device at the current time t, which is used to adjust the balance between energy consumption and signal duration. The smaller the duty cycle, the lower the average power consumption; Indicates the energy conversion efficiency of the power amplifier of the nth visibility detection device, which characterizes the effectiveness of energy conversion. Improving the energy conversion efficiency can reduce energy loss and allow the same Use higher , It represents the average power corresponding to the pulse transmitted by the nth visibility detection device in a single cycle; represents the signal-to-noise ratio corresponding to the pulse train transmitted by the nth visibility detection device at time t, The noise power spectral density of the ambient noise on the nth visibility detection device's transmitted pulse train, representing the intensity of environmental interference. For example, heavy rain can cause a sudden increase in noise power. In this case, the instantaneous power needs to be dynamically increased or the transmission angle needs to be adjusted to maintain the signal-to-noise ratio above the detection threshold. If the noise primarily comes from heat sources, the noise sampling time in the low-level window needs to be shortened to reduce the cumulative impact of noise. This variable can be used to more accurately balance the duty cycle and instantaneous power of the transmitted pulse train, thereby reducing energy consumption while improving the signal-to-noise ratio of the corresponding power of the transmitted pulse train, keeping the average power consumption corresponding to each transmission cycle at a very low level. It represents the high-level window width corresponding to the pulse train transmitted by the nth visibility detection device at the current time t, Indicates the low-level window width corresponding to the pulse train transmitted by the nth visibility detection device at time t, The emission angle corresponding to the infrared signal emitted by the nth visibility detection device at the current time t, This represents the emission angle gain factor corresponding to the infrared signal emitted by the nth visibility detection device at time t. This factor determines the concentration of infrared signal radiation in a specific direction. By dynamically adjusting the emission angle, for example, from 45° to 30°, the system can focus energy on the target detection area and reduce ineffective scattering losses. It represents the thermal noise value corresponding to the nth visibility detection device, i.e., the ambient thermal noise, which is related to the temperature; represents the probability of the nth visibility detection device being detected when emitting an infrared signal at the mth instantaneous power level; is the single pulse energy of the nth visibility detection device at the current moment t; is the equivalent noise bandwidth of the receiving end corresponding to the nth visibility detection device; further, in this embodiment, ;

[0062] Based on the signal excitation instantaneous power level interval and the average power threshold corresponding to the transmitted pulse in a single cycle in the signal transmission information sequence, the upper and lower limits of the high-level window width corresponding to the reference clock pulse train, and the transmission angle interval, a duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation and corresponding search constraints are constructed;

[0063] Based on the duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation and the corresponding search constraints, a multi-objective optimization discrimination algorithm and a two-way search rule are combined to search and solve the problem. The optimal duty cycle and optimal emission angle corresponding to the maximum probability of detecting the infrared signal at each instantaneous power level are obtained.

[0064] Based on the optimal duty cycle corresponding to each instantaneous power level and the reference clock pulse string, a multi-level variable coded pulse string is obtained and distinguished coding is marked, and decoding information corresponding to the distinguished coding is pre-stored in the signal receiving device.

[0065] Furthermore, a duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation is constructed by those skilled in the art based on the signal-to-noise ratio formula, the relationship formula between average power, instantaneous power and duty cycle, the duty cycle calculation formula, and the maximum detection probability formula corresponding to the signal-to-noise ratio and duty cycle-instantaneous power using the Bayesian algorithm combined with nonlinear mirror kernel function fitting, combined with the above variables, and solved accordingly using a multi-objective linear algorithm;

[0066] Furthermore, the constraints corresponding to the present invention are specifically as follows: ,in 、 They are the lower limit and upper limit of the instantaneous power level range of the signal excitation, respectively. Here, the corresponding power levels are divided according to the density of the corresponding transmitted signal in the actual detection process. The specific division will be made by those skilled in the art according to specific needs; ;

[0067] Furthermore, the total average power corresponding to the visibility detection device in this embodiment per unit time length is less than 0.009W. Therefore, the solar power generation device configured for the visibility detection device of this application can fully meet the power supply process of the corresponding detection device.

[0068] Furthermore, in this embodiment, the average power corresponding to the transmitted pulse in a single cycle is less than the total average power corresponding to the visibility detection device in a unit time length;

[0069] Furthermore, in this embodiment, the average power threshold corresponding to the transmitted pulse in a single cycle is obtained by radial kernel function fitting based on the ratio of the power corresponding to the transmitted pulse in a single cycle of the historical visibility detection device to the power used by the remaining other devices and the corresponding duty cycle; the remaining other devices include the receiving end, the infrared signal transmitting end and the display device, etc.

[0070] Furthermore, in the process of constructing the distinctive code, this embodiment first generates an unpredictable pulse interval sequence based on a modified logistic mapping combined with a pulse train with a corresponding duty cycle. Subsequently, orthogonal subcarriers are superimposed on the fundamental frequency of this pulse interval sequence to form a spectral fingerprint. This is used to obtain the distinctive code of the corresponding pulse train and the corresponding decoding information, which is then synchronously pre-stored at the receiving end. In this embodiment, the modified logistic mapping algorithm is preferably a Cubic-Logistic hybrid mapping algorithm.

[0071] Furthermore, the process of the bidirectional search rule in this embodiment includes:

[0072] Based on the upper and lower limits of the high-level window width and the instantaneous power level range of the signal excitation, the upper limit of the high-level window width corresponding to the standard duty cycle is used as the search starting point, and each high-level window width value is searched downward, and the duty cycle of the corresponding window width is obtained with each high-level window width;

[0073] At the same time, based on the duty cycle corresponding to each window width, a double search is performed from the lower limit to the upper limit of the signal excitation instantaneous power level interval and the emission angle interval, under the condition that the average power threshold corresponding to the emission pulse in a single cycle is met, to obtain each optimal duty cycle and the power level sequence that meets the average power threshold under each optimal duty cycle and the optimal emission angle corresponding to the maximum probability of the infrared signal being detected under the optimal duty cycle.

[0074] Furthermore, in this embodiment, when searching from the lower limit to the upper limit of the signal excitation instantaneous power level interval and the emission angle interval, a fixed emission angle is used within one transmission cycle, and then cyclic transmission is performed from large to small within the signal excitation instantaneous power level interval. When the current cycle is completed, the next emission angle is fixed, and the above power level cycle process is repeated until the search is completed. That is, assuming that the power level sequence includes levels 1-5, if visibility is not detected after transmitting levels 1-5 at the current transmission angle of 39 degrees, the transmission angle is adjusted to 40 degrees and cyclic transmission is performed for power levels 1-5. The above process is repeated in this way to perform cyclic visibility detection within the signal excitation instantaneous power level interval and the emission angle interval.

[0075] Furthermore, in this embodiment, the step of obtaining the visibility corresponding to the target detection area includes:

[0076] Based on a power level sequence that satisfies an average power threshold corresponding to each duty cycle, infrared rays corresponding to a power level sequence for each duty cycle are generated through the hierarchical power control model, and infrared rays of different power levels with distinguishing codes are cyclically emitted from high to low power levels at the optimal emission angle corresponding to the current duty cycle;

[0077] Based on the signal receiving device configured for each visibility detection device, the corresponding target detection area signal is collected in real time, and the real-time collected target detection area signal is filtered by combining the marked distinctive code and the decoding information corresponding to the distinctive code through a filtering algorithm, and at the same time, it is determined whether the filtered target detection area collected signal contains an infrared ray signal with the distinctive code;

[0078] If it exists, the infrared ray signal information with the discriminative code obtained is input into the matching detection algorithm and combined with the signal power level-visibility mapping table to match the infrared ray signal with the discriminative code with the corresponding power level to obtain the visibility of the current target detection area corresponding to the matching level;

[0079] Furthermore, the signal power level-visibility mapping table in this embodiment is constructed by those skilled in the art based on historical experimental test data for different weather conditions and road areas combined with hash table analysis. In actual applications, based on a preset update function, the duty cycle and power level corresponding to the maximum visibility detection probability that are not present in the signal power level-visibility mapping table are updated into the signal power level-visibility mapping table.

[0080] If it does not exist, the infrared ray signal at the power level corresponding to each duty cycle is transmitted, collected and detected and matched in a cyclic manner from high to low power levels until the visibility of the current target detection area is detected;

[0081] When the visibility detection device corresponding to the current interval detects the corresponding visibility, and at least one of the two adjacent visibility detection devices does not detect the corresponding visibility, the power level and duty cycle information corresponding to the current interval visibility are shared to the preset power level-visibility one-to-one mapping table of the adjacent visibility detection device that has not detected the visibility, and the emission priority of the infrared rays corresponding to the shared power level and duty cycle is set to the highest.

[0082] Furthermore, in this embodiment, the process of matching the infrared ray signal with the distinctive code to the corresponding power level includes:

[0083] The identified infrared ray signal is filtered using a Butterworth bandpass filter. By setting the filter cutoff frequency and order, noise in non-target frequency bands is filtered out and the infrared signal to be matched is extracted.

[0084] Based on the infrared signal to be matched, combined with the pre-stored Logistic chaotic sequence, decoding is performed, and the infrared ray signal matching the chaotic sequence is extracted by calculating the cross-correlation function between the signal to be matched and the pre-stored chaotic sequence;

[0085] The power level of the infrared ray signal obtained by the judgment is compensated according to the preset power reduction coefficient. The power reduction coefficient is dynamically adjusted according to the signal attenuation model to compensate for the power loss during the signal transmission process.

[0086] The differential code corresponding to the compensated infrared ray signal is mapped to a hash bucket through a hash function. The hash bucket stores a mapping table between signal power level and visibility. The power level corresponding to the signal is quickly located through hash mapping.

[0087] The key in the distinguishing code in this embodiment is the CRC-16 checksum of the encoded fingerprint, and the value is the power level;

[0088] Furthermore, the power reduction factor in this embodiment is obtained by analyzing historical measured data under different environments and visibility conditions, and is stored in the above-mentioned signal power level-visibility one-to-one mapping table in one-to-one correspondence with the corresponding power level.

[0089] Furthermore, the CRC-16 check value in this embodiment is generated by the improved Logistic mapping, including 256 groups of chaotic sequences (length 64), each group of chaotic sequences corresponding to a unique CRC-16 check value;

[0090] Furthermore, the cyclic emission in this embodiment is a cyclic emission process achieved by emitting infrared rays generated in descending order of power according to a power level sequence corresponding to each optimal duty cycle.

[0091] Furthermore, in this embodiment, in order to more clearly illustrate the process of setting the emission priority of infrared rays corresponding to the shared power level and duty cycle to the highest, for example, when a visibility detection device successfully detects visibility but two adjacent visibility detection devices do not detect it, the system will share the valid parameters of the visibility detection device corresponding to the detected visibility value (such as power level, duty cycle, emission angle) to the two adjacent devices, and put the emission time of the infrared rays corresponding to the shared parameters at the front, and increase the emission frequency.

[0092] Based on the above process, this embodiment can achieve the following effects. In particular, by generating a variable coded pulse train based on the preset initial duty cycle of the visibility detection device in combination with discrete time-sharing coding control rules, and utilizing a signal power amplifier device to obtain a multi-level variable coded pulse train, multi-level power control of the infrared signal is achieved. This design not only adapts to the visibility detection needs under different environmental conditions, but also cyclically excites infrared signals of different light intensities and emission angles through a graded power control model combined with emission angle intervals, thereby significantly improving the signal's penetration and detection accuracy in complex environments. Secondly, the visibility detection device internally utilizes all-digital CMOS logic circuits, eliminating the use of a single-chip processor. This design significantly enhances the system's anti-interference capabilities and ensures the precise generation of pulse signals and the cyclic modulation of infrared ray light intensity. In addition, by configuring a conical total reflection condenser as a signal receiving device, the amount of light entering is significantly increased, while the overall size of the equipment is reduced, the cost of use is reduced, and it provides feasibility for large-scale deployment; secondly, in terms of signal processing, the present invention uses a Butterworth bandpass filter to filter the infrared signal, combines it with a Logistic chaotic sequence for decoding, extracts the matching infrared ray signal, and quickly locates the power level corresponding to the signal through hash mapping. This process not only improves the efficiency of signal processing, but also dynamically compensates the signal power level through a preset power reduction coefficient, further optimizing the stability and reliability of signal transmission. In addition, by constructing a duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation and corresponding search constraints, and combining a multi-objective optimization discrimination algorithm with a two-way search rule for search and solution, the optimal duty cycle and optimal emission angle are obtained, ensuring that the probability of the infrared signal being detected at each instantaneous power level is maximized. This optimized design not only improves the success rate of signal detection, but also reduces invalid scattering losses and further reduces energy consumption by dynamically adjusting the emission angle and power level. Thirdly, in the specific implementation of visibility detection, the present invention generates infrared rays of different power levels through a hierarchical power control model, and filters and matches the target detection area signal in combination with distinguishing encoding and decoding information, thereby achieving accurate inversion of visibility. Through a one-to-one mapping table of signal power level-visibility, the system can update and display the visibility information of the target detection area in real time. In addition, when a visibility detection device successfully detects visibility and an adjacent device does not detect it, the system will share the power level and duty cycle information corresponding to the detected visibility value with the adjacent device, and set the emission priority of the infrared ray corresponding to the shared parameters to the highest.This design not only improves the detection efficiency of adjacent devices, but also further optimizes the overall performance of the system through information sharing and priority adjustment. In addition, this embodiment also generates an unpredictable pulse interval sequence through improved Logistic mapping, and combines orthogonal subcarriers to form a spectrum fingerprint, thereby realizing the pre-storage of distinguishing encoding and decoding information of the pulse string. This design not only improves the security and anti-interference capability of the signal, but also ensures the uniqueness and reliability of the encoding through the CRC-16 check value. In addition, by dynamically adjusting the transmission angle and power level, the system can achieve optimal signal transmission and reception effects under different environmental conditions, further improving the accuracy and stability of visibility detection. Overall, the present invention realizes efficient, accurate, and low-energy visibility detection through multi-level technical optimization and innovative design, providing reliable technical support for visibility monitoring in complex environments.

[0093] Example 2

[0094] See also Figure 4 , another embodiment provided by the present invention: a visibility detection device, comprising: a pulse train generation module, a power amplification module, a signal excitation module, a detection and discrimination module and a real-time display module;

[0095] A pulse train generating module generates a variable coded pulse train based on an initial duty cycle preset by the visibility detection device and a preset discrete time-sharing coding control rule;

[0096] The power amplifier module obtains a multi-level variable coded pulse train based on the variable coded pulse train through the signal power amplifier device;

[0097] The signal excitation module, based on a multi-level variable coded pulse train, uses a preset hierarchical power control model combined with a preset emission angle range to cyclically excite infrared signals of different light intensities and emission angles in the target detection area;

[0098] The detection and discrimination module collects the infrared signals scattered from the target detection area in real time through the signal receiving device configured in the visibility detection device, and uses a preset filtering and discrimination evaluation model to synchronously combine the multi-level variable coded pulse train information to match and discriminate whether there is an infrared signal of the corresponding power level in the infrared signals collected from the target detection area;

[0099] The real-time display module is used to invert the visibility corresponding to the target detection area based on the infrared signal of the current power level of the detected target detection area combined with the signal power level-visibility one-to-one mapping table.

[0100] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also change, modify, replace and modify the above-mentioned embodiments without departing from the scope of protection of the purpose of the present invention and the claims, and all of these are protected by the present invention.

Claims

1. A visibility detection method, characterized in that: include: Based on the initial duty cycle preset by the visibility detection device and the preset discrete time-sharing coding control rule, a variable coded pulse train is generated; Based on the variable coded pulse train, a multi-level variable coded pulse train is obtained through a signal power amplifier; Based on the multi-level variable coded pulse train, a preset hierarchical power control model is combined with a preset emission angle interval to cyclically stimulate infrared signals of different light intensities and emission angles in the target detection area; The signal receiving device configured in the visibility detection device collects the infrared signals scattered from the target detection area in real time, and uses a preset filtering and discrimination evaluation model to synchronously combine the multi-level variable coded pulse train information to match and judge whether there is an infrared signal of corresponding power level in the infrared signals collected from the target detection area; If it exists, the visibility corresponding to the target detection area is inverted by combining the current power level infrared signal detected with the preset signal power level-visibility mapping table and updated in real time; The acquisition process of the multi-level variable coded pulse train includes: Generate the reference clock pulse train sequence required by the visibility detection device through clock control at an excitation frequency of 38 kHz and a preset initial duty cycle; Using a counter to measure the reference clock pulse train sequence, obtain the period length T corresponding to the reference clock signal and the high-level window width and the adjacent low-level window width in each period; Based on the period length T corresponding to the reference clock signal and the high-level window width in each period, a standard duty cycle of the reference clock signal is obtained; Preset the signal excitation instantaneous power level range and obtain the signal transmission information sequence corresponding to the maximum signal detection intensity detected in each historical visibility detection process; Based on the signal excitation instantaneous power level interval and the average power threshold corresponding to the transmitted pulse in a single cycle in the signal transmission information sequence, the upper and lower limits of the high-level window width corresponding to the reference clock pulse train, and the transmission angle interval, the duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation and the corresponding search constraints are constructed.

2. A visibility detection method according to claim 1, characterized in that: The acquisition process of the multi-level variable coded pulse train further includes: Based on the duty cycle-instantaneous power level-maximum signal-to-noise ratio search equation and the corresponding search constraints, a multi-objective optimization discrimination algorithm and a two-way search rule are combined to search and solve the problem. The optimal duty cycle and optimal emission angle corresponding to the maximum probability of detecting the infrared signal at each instantaneous power level are obtained. Based on the optimal duty cycle corresponding to each instantaneous power level and the reference clock pulse string, a multi-level variable coded pulse string is obtained and distinguished coding is marked, and decoding information corresponding to the distinguished coding is pre-stored in the signal receiving device.

3. A visibility detection method according to claim 2, characterized in that: The process of the bidirectional search rule includes: Based on the upper and lower limits of the high-level window width and the instantaneous power level range of the signal excitation, the upper limit of the high-level window width corresponding to the standard duty cycle is used as the search starting point, and each high-level window width value is searched downward, and the duty cycle of the corresponding window width is obtained with each high-level window width; At the same time, based on the duty cycle corresponding to each window width, a double search is performed from the lower limit to the upper limit of the signal excitation instantaneous power level interval and the emission angle interval, under the condition that the average power threshold corresponding to the emission pulse in a single cycle is met, to obtain each optimal duty cycle and the power level sequence that meets the average power threshold under each optimal duty cycle and the optimal emission angle corresponding to the maximum probability of the infrared signal being detected under the optimal duty cycle.

4. A visibility detection method according to claim 3, characterized in that: The step of acquiring the visibility corresponding to the target detection area includes: Based on a power level sequence that satisfies an average power threshold corresponding to each duty cycle, infrared rays corresponding to a power level sequence for each duty cycle are generated through the hierarchical power control model, and infrared rays of different power levels with distinguishing codes are cyclically emitted from high to low power levels at the optimal emission angle corresponding to the current duty cycle; The signal receiving device configured based on each visibility detection device collects the corresponding target detection area signal in real time, and filters the real-time collected target detection area signal through a filtering algorithm combined with the marked distinction code and the decoding information corresponding to the distinction code, and at the same time determines whether the filtered target detection area collection signal contains an infrared ray signal with a distinction code.

5. A visibility detection method according to claim 4, characterized in that: The step of acquiring the visibility corresponding to the target detection area further includes: If it exists, the infrared ray signal information with the discriminative code obtained is input into the matching detection algorithm and combined with the signal power level-visibility mapping table to match the infrared ray signal with the discriminative code with the corresponding power level to obtain the visibility of the current target detection area corresponding to the matching level; If it does not exist, the infrared ray signal at the power level corresponding to each duty cycle is transmitted, collected and detected and matched in a cyclic manner from high to low power levels until the visibility of the current target detection area is detected; When the visibility detection device corresponding to the current interval detects the corresponding visibility, and at least one of the two adjacent visibility detection devices does not detect the corresponding visibility, the power level and duty cycle information corresponding to the current interval visibility are shared to the preset power level-visibility one-to-one mapping table of the adjacent visibility detection device that has not detected the visibility, and the emission priority of the infrared rays corresponding to the shared power level and duty cycle is set to the highest.

6. A visibility detection method according to claim 5, characterized in that: The preset emission angle interval is ; The signal receiving device configured in the visibility detection device is a conical total reflection condenser.

7. A visibility detection device, used to implement a visibility detection method according to any one of claims 1 to 6, characterized in that: include: Pulse train generation module, power amplification module, signal excitation module; The pulse train generating module generates a variable coded pulse train based on the initial duty cycle preset by the visibility detection device and the preset discrete time-sharing coding control rule; The power amplification module obtains a multi-level variable coded pulse train based on the variable coded pulse train through a signal power amplifier; The signal excitation module, based on the multi-level variable coded pulse train, cyclically excites infrared signals of different levels of light intensity and emission angles to the target detection area through a preset hierarchical power control model combined with a preset emission angle interval.

8. A visibility detection device according to claim 7, characterized in that: The visibility detection device also includes a detection and discrimination module and a real-time display module; The detection and discrimination module collects infrared signals scattered from the target detection area in real time through the signal receiving device configured by the visibility detection device, and uses a preset filtering and discrimination evaluation model to synchronously combine multi-level variable coded pulse train information to match and discriminate whether there is an infrared signal of corresponding power level in the infrared signals collected from the target detection area; The real-time display module is used to inversely obtain the visibility corresponding to the target detection area based on the infrared signal of the current power level of the detected target detection area combined with a signal power level-visibility one-to-one mapping table.

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