Forest security inspection method and system

Abstract

The invention discloses a forest security inspection method and system, and belongs to the technical field of security inspection, the method adopts a moving mechanism carrying a forest security inspection system to carry out security inspection, and the method comprises the following steps: preprocessing the forest security inspection system, the preprocessing comprising setting a security inspection route; the moving mechanism carries out security inspection according to the set route, wherein the security inspection comprises logging detection and fire detection; when an illegal felling behavior is detected, a moving mechanism is driven to move to an illegal felling position according to a sound source positioning and navigation method, voice broadcasting is carried out to drive an illegal felling person, illegal felling information is uploaded to a forest security inspection system control end, and the illegal felling information comprises illegal felling positioning information and illegal felling image information; when a fire is detected, a fire alarm is broadcasted through voice, and fire information is uploaded to a control end of the forest security inspection system, wherein the fire information comprises fire positioning information and fire image information. The system and the method are suitable for daily security inspection of forest theft felling and fire disasters.

Description

Technical Field

[0001] The present invention belongs to the technical field of security patrol for forests, and particularly relates to a method and system for security patrol in forest security. Background Art

[0002] In recent years, forest theft and fires have been common, causing great damage to forestry resources and the ecological environment. At present, preventing forest theft mainly relies on manual inspections and reports from the public. This method has great limitations in terms of time and space, and the logging and transportation tools of thieves are becoming more and more advanced, which also increases the difficulty of inspections.

[0003] Using satellite remote sensing is another way to detect logging behavior. However, satellite remote sensing can only detect large and obvious logging areas, and it is difficult to detect logging in a timely manner. Moreover, the hardware construction and operation costs of satellite remote sensing are high, and it requires a high level of technical expertise for maintenance personnel, so its popularity is not good.

[0004] In response to the frequent occurrence of forest fires, common patrol methods include drones and satellite remote sensing. However, it is not easy to detect fire risks in the early stage of a fire, thus losing valuable time for fire fighting and causing huge property and ecological losses. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method and system for security patrol in forest security, which is suitable for daily security patrol of forest theft and fires.

[0006] To achieve the above object, the present invention is implemented by the following technical solutions:

[0007] In the first aspect, the present invention provides a method for security patrol in forest security, which uses a mobile mechanism equipped with a forest security patrol system to conduct security patrol, including:

[0008] S1: Preprocess the forest security patrol system, and the preprocessing includes setting a security patrol route;

[0009] S2: The mobile mechanism conducts security patrol according to the route set in step S1, and the security patrol includes logging detection and fire detection;

[0010] S3: When logging behavior is detected in step S2, the mobile mechanism is driven to move to the logging location according to the sound source localization and navigation method, and a voice broadcast is used to drive away the loggers and upload the logging information to the control end of the forest security patrol system. The logging information includes logging location information and logging image information;

[0011] When a fire is detected in step S2, a voice broadcast of a fire warning is made and the fire information is uploaded to the control terminal of the forest security patrol system. The fire information includes fire location information and fire image information.

[0012] The aforementioned forest security patrol method further includes:

[0013] S4: The control terminal of the forest security patrol system performs alarm processing on the logging information and / or fire information reported in step S3. After the processing is completed, the mobile mechanism returns to the original security patrol route to continue the security patrol of the remaining route or performs the security patrol according to the set new route;

[0014] S5: When the security patrol route set in step S1 or step S4 is completed, the mobile mechanism returns to the preset starting point or performs the next security patrol.

[0015] In the aforementioned forest security patrol method, the logging detection method in step S2 includes:

[0016] S211: Set the spectral characteristics of the logging sound and the similarity threshold of the logging sound according to the pre-experiment results;

[0017] S212: During the security patrol process, collect audio data for a preset duration;

[0018] S213: Preprocess the audio data collected in step S212;

[0019] S214: Perform feature analysis on the audio data processed in step S213. The feature analysis includes spectral analysis and cross-correlation calculation;

[0020] S215: Compare the spectral analysis result of step S214 with the spectral characteristics of the logging sound set in step S211 to determine whether the audio data collected in step S212 meets the spectral characteristics conditions of the logging sound;

[0021] Compare the cross-correlation calculation result of step S214 with the similarity threshold of the logging sound set in step S211 to determine whether the audio data collected in step S212 meets the similarity conditions of the logging sound;

[0022] S216: Determine whether the audio collected in step S12 is logging audio according to the judgment result of step S215;

[0023] When the audio data collected in step S212 meets the spectral characteristics conditions and similarity conditions of the logging sound in step S215, it is determined that the audio data collected in step S212 is logging audio;

[0024] When the audio data collected in step S212 does not meet the logging sound spectrum feature condition and / or the logging sound similarity condition of step S215, jump to step S212;

[0025] S217: Accumulate the number of times of determining whether it is logging audio in step S216 to a preset determination number of times;

[0026] S218: Determine whether the accumulated number of times of determining as logging audio in the preset determination number of times in step S217 reaches a preset number threshold;

[0027] S219: If the accumulated number of times of determining as logging audio reaches the preset number threshold, it is determined that illegal logging behavior is detected; if the accumulated number of times of determining as logging audio does not reach the preset number threshold, initialize the accumulated number of times in step S217 and jump to step S212.

[0028] In the aforementioned forest security patrol method, the fire detection method in step S2 includes detecting fire by thermal imaging;

[0029] The detecting fire by thermal imaging includes:

[0030] S221: Initialize and set parameters for the microcontroller and infrared imaging sensor for thermal imaging detection, and the parameter setting includes a preset temperature threshold;

[0031] S222: Use the infrared imaging sensor in step S221 to collect data to generate an image;

[0032] S223: Detect bad pixels in the image pixels generated in step S222 and perform averaging processing on the bad pixels;

[0033] S224: After a preset delay, transmit the corresponding highest temperature value among the pixels processed in step S223 to the microcontroller in step S221;

[0034] S225: Compare the highest temperature value in step S224 with the preset temperature threshold in step S221;

[0035] S226: When the highest temperature value is greater than the preset temperature threshold, it is determined that a fire has occurred in the data collection area in step S222;

[0036] When the highest temperature value is not greater than the preset temperature value, jump to step S222.

[0037] In the aforementioned forest security patrol method, the fire detection in step S2 further includes detecting fire by smoke alarm, and the detecting fire by smoke alarm includes:

[0038] S231: The smoke sensor collects smoke information;

[0039] S232: Count the number of alarms of the smoke sensor;

[0040] S233: When the number of alarms of the smoke sensor exceeds the set threshold, it is determined that a fire has occurred in the smoke alarm detection and collection area.

[0041] In the aforementioned forest security patrol method, in step S3, driving the mobile mechanism to move to the deforestation location according to the sound source localization and navigation method includes:

[0042] S31: Perform sound source localization according to the sound source localization method;

[0043] S32: Drive the mobile mechanism to move to the deforestation location according to the sound source localization obtained in step S31 in combination with the sound source navigation method;

[0044] Step S31 includes:

[0045] S311: Calculate the time difference of arrival of multiple sound source receivers respectively;

[0046] S312: Perform sound source localization according to the time difference of arrival calculated in step S311, the sound propagation speed, and the distance between the sound source receivers;

[0047] In step S311, the calculation method of the time difference of arrival of each sound source receiver includes:

[0048] S3111: Sample two groups of sound source data using an analog-to-digital converter;

[0049] S3112: Perform fast Fourier transform on the sound source data sampled in step S3111 in groups;

[0050] S3113: Perform conjugate processing on one group of the data after the fast Fourier transform in step S3112;

[0051] S3114: Multiply the data after the conjugate processing in step S3113 by the other group of data;

[0052] S3115: Perform inverse fast Fourier transform on the multiplication result in step S3114 to obtain the cross-correlation function of the two groups of sound source data;

[0053] S3116: Record the peak subscript of the cross-correlation function in step S3115;

[0054] S3117: Convert the peak subscript in step S3116 to time to obtain the time difference of arrival.

[0055] In the aforementioned forest security patrol method, step S32 includes:

[0056] S321: Determine the target forward direction and target forward distance of the mobile mechanism according to the current position of the mobile mechanism and the sound source localization obtained in step S31;

[0057] S322: Determine the current heading angle and moving speed according to the distance from surrounding obstacles, the target forward direction, and the target forward distance, in combination with the PID algorithm;

[0058] S223: Loop and execute steps S321 and S322 until the moving mechanism moves to the illegal logging location.

[0059] In a second aspect, the present invention provides a forest security patrol system for the forest security patrol method described in the first aspect. The forest security patrol system includes a logging detection module, a fire detection module, a sound source localization module, a sound source navigation module, and a voice broadcast module;

[0060] The logging detection module is used to detect illegal logging behavior according to the logging detection method;

[0061] The fire detection module is used to detect fires according to the fire detection method;

[0062] The sound source localization module is used to perform sound source localization on the illegal logging location after the logging detection module detects illegal logging behavior;

[0063] The sound source navigation module is used to drive the moving mechanism to move to the illegal logging location determined by the sound source localization module;

[0064] The voice broadcast module is used to broadcast corresponding voices according to the security patrol situation. When the logging detection module detects a fire, the voice broadcast module broadcasts a fire warning; when the moving mechanism moves to the illegal logging location, the voice broadcast module broadcasts to drive away the illegal loggers.

[0065] The aforementioned forest security patrol system further includes a power supply module, a communication module, and an image transmission module;

[0066] The power supply module is used to supply power to the forest security patrol system and the moving mechanism;

[0067] The communication module is used for communication between the forest security patrol system and the control end of the forest security patrol system. The communication module is signal-connected to the control end of the forest security patrol system, and the communication module is respectively connected to the logging detection module, the fire detection module, the sound source localization module, the sound source navigation module, the voice broadcast module, the power supply module, and the image transmission module;

[0068] The image transmission module is used to store the image information during the security patrol and upload the stored image information to the control end of the forest security patrol system. When the fire detection module detects a fire, the image transmission module uploads the fire image information; when the moving mechanism moves to the illegal logging location, the image transmission module uploads the illegal logging image information;

[0069] The fire image information includes the fire scene image and the fire thermal imaging image. The generation of the fire thermal imaging image includes: transmitting the thermal imaging image detected by the fire detection module to the image transmission module after bilinear interpolation processing.

[0070] The aforementioned forest security patrol system, the control end of the forest security patrol system includes a control end human-computer interaction interface, and the control end human-computer interaction interface includes a control page and a data page;

[0071] The control page includes alarm information display, remote control, and manual voice broadcast;

[0072] The alarms of the alarm information display are divided into illegal logging alarms and fire alarms. The information display of the illegal logging alarm includes illegal logging location information and illegal logging image information, and the information display of the fire alarm includes fire location information and fire image information;

[0073] Remote control is used to remotely control the movement of the mobile mechanism and call and view the security patrol site images; the movement of the mobile mechanism includes forward, backward, left turn, right turn, and stop moving, and the security patrol site images include historical images and real-time images of the security patrol site;

[0074] Manual voice broadcast is used to manually send voice broadcasts to the forest security patrol system. The voice broadcasts include driving away illegal loggers and fire warnings, or, the voice broadcasts include driving away illegal loggers, fire warnings, and custom voice content;

[0075] The data page is used to display the positioning information of the mobile mechanism on the map, and set or change the security patrol route;

[0076] Or,

[0077] Display the positioning information of the mobile mechanism on the map, and set or change the security patrol route;

[0078] The positioning information of the mobile mechanism displayed on the map includes: zooming in or out the image display area of the mobile mechanism on the map;

[0079] There are several security patrol routes, and the setting or changing of the security patrol route includes:

[0080] Respectively set or change the starting position, ending position, patrol start time, patrol start and patrol stop of each security patrol route;

[0081] After setting or changing a security patrol route, the mobile mechanism stops patrolling and returns to the preset starting point or starts the next security patrol route;

[0082] When there are multiple security patrol routes, set or change the execution order of the security patrol routes.

[0083] Advantages achieved by the present invention compared with the prior art:

[0084] The present invention uses a mobile mechanism equipped with a forest security inspection system for security inspections. The mobile mechanism conducts security inspections on illegal logging behaviors and fire situations according to a set route, and corresponding treatment measures are taken for detected illegal logging behaviors and / or fire situations, which is applicable to the daily security inspections of forest illegal logging and fires.

[0085] Compared with the existing manual inspections, by equipping the mobile mechanism with a sound source receiver and using a logging detection method and a sound source localization method, the present invention can quickly lock in illegal logging behaviors, issue alarms in a timely manner and drive away illegal loggers, effectively protecting forest resources from illegal infringement.

[0086] Compared with the existing unmanned aerial vehicles and remote sensing technologies, by using infrared thermal imaging technology, the mobile mechanism of the present invention can detect abnormal high-temperature areas at the initial stage of a fire, quickly upload the fire coordinate information, win valuable time for early fire fighting, and greatly reduce the damage of the fire to forest resources.

[0087] Through the human-machine interaction interface of the control terminal of the forest security inspection system, managers can remotely monitor the inspection images, process alarm information, and can remotely operate the mobile mechanism to efficiently perform security tasks; the mobile mechanism can conduct security inspections according to the set route by itself, avoiding managers facing the illegal loggers or the fire scene alarm situation directly, and improving the personal safety of managers during security inspections. The present invention has good adaptability to the supporting mobile mechanism, so different mobile mechanisms can be selected according to the geographical characteristics of different security inspection areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 is a schematic flow chart of the forest security inspection method according to Embodiment 1 of the present invention;

[0089] Figure 2 is a schematic structural diagram of a forest security inspection system according to Embodiment 2 of the present invention;

[0090] Figure 3 is a schematic flow chart of a logging detection method according to Embodiment 1 of the present invention;

[0091] Figure 4 is a schematic flow chart of detecting a fire by thermal imaging according to Embodiment 1 of the present invention;

[0092] Figure 5 is a schematic flow chart of a sound source localization method according to Embodiment 1 of the present invention;

[0093] Figure 6 is a schematic flow chart of a sound source navigation method according to Embodiment 1 of the present invention;

[0094] Figure 7 It is a schematic diagram of a man - machine interaction interface of the control end of the forest security inspection system in Embodiment 2 of the present invention Figure 1 ;

[0095] Figure 8 It is a schematic diagram of a man - machine interaction interface of the control end of the forest security inspection system in Embodiment 2 of the present invention Figure 2 ; Detailed implementation manners

[0096] The technical solution of the present invention will be described in detail below through the accompanying drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other

[0097] The term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after

[0098] Embodiment 1:

[0099] Figure 1 It is a flow chart of a forest security inspection method in Embodiment 1 of the present invention. This flow chart only shows the logical order of the method described in this embodiment. On the premise of no conflict, in other possible embodiments of the present invention, the steps shown or described can be completed in a different order Figure 1 than that shown

[0100] The forest security inspection method in this embodiment uses a mobile mechanism equipped with a forest security inspection system to perform security inspections, including:

[0101] S1: Pre - process the forest security inspection system, and the pre - processing includes setting a security inspection route;

[0102] S2: The mobile mechanism performs security inspections according to the route set in step S1, and the security inspections include logging detection and fire detection;

[0103] S3: When the logging behavior is detected in step S2, drive the mobile mechanism to move to the logging location according to the sound source localization and navigation method, perform voice broadcast to drive away the loggers, and upload the logging information to the control end of the forest security inspection system. The logging information includes logging location information and logging image information;

[0104] When a fire is detected in step S2, a voice broadcast of a fire warning is made and the fire information, including fire location information and fire image information, is uploaded to the control end of the forest security patrol system.

[0105] The above forest security patrol method can be applied to the daily security patrol of forest logging and fires.

[0106] When logging information and / or fire information is detected, in addition to the processing at the patrol site, it is also necessary to notify the control end of the forest security patrol system and perform subsequent processing on the mobile mechanism. Therefore, the forest security patrol method of this embodiment further includes:

[0107] S4: The control end of the forest security patrol system performs alarm processing on the logging information and / or fire information reported in step S3. After the processing is completed, the mobile mechanism returns to the original security patrol route to continue the security patrol of the remaining route or performs the security patrol according to the set new route.

[0108] After the control end of the forest security patrol system receives the alarm information, different treatments are carried out according to the severity and development of the alarm situation. For example, when large-scale logging is detected, while the forest security patrol system monitors the logging process in real time, forest rangers are organized to go to the logging site for treatment.

[0109] S5: When the security patrol route set in step S1 or step S4 is completed, the mobile mechanism returns to the preset starting point or performs the next security patrol.

[0110] When specifically implementing the forest security patrol method of this embodiment:

[0111] The logging detection method in step S2, as Figure 3 shown, includes:

[0112] S211: Set the logging sound spectrum characteristics and the logging sound similarity threshold according to the pre-experiment results.

[0113] The aforementioned pre-experiment refers to conducting comparative experiments under various environmental conditions, measuring sound data, analyzing the measured sound data, extracting the logging sound spectrum characteristics that mark the logging sound and the logging sound similarity threshold for judging the logging sound, and setting the logging sound similarity threshold and the logging sound spectrum characteristics according to the extracted data results. The aforementioned various environments refer to the experimental environment with other sounds superimposed on the logging sound and the experimental environment with only the logging sound. Among them, the logging sound includes different logging sounds generated by different logging tools.

[0114] S212: During the security patrol process, collect audio data for a preset duration.

[0115] Too short audio data cannot extract sufficient effective information for subsequent processing, while too long audio data affects the timeliness of subsequent processing. Therefore, it is necessary to collect audio data of a preset duration for subsequent unified processing to avoid the collected audio data affecting the accuracy and timeliness of the subsequent judgment result of logging sounds. The preset duration can be determined through pre-experiments. In this embodiment, the preset duration is set to 4 seconds.

[0116] S213: Preprocess the audio data collected in step S212;

[0117] The preprocessing includes passing through a filter to filter out noise, and other noise reduction methods can also be used to remove the background noise that may be introduced during the audio data collection process to improve the quality of the audio data. The preprocessing also includes normalization processing to adjust the amplitude of the audio data, making the collected audio data easier to compare and improving the accuracy of subsequent cross-correlation calculation and spectral feature comparison.

[0118] S214: Perform feature analysis on the audio data processed in step S213. The feature analysis includes spectral analysis and cross-correlation calculation; the spectral analysis is to convert the audio data processed in step S213 into a spectrum for feature comparison, and the cross-correlation calculation is a calculation to measure the similarity degree between two audio data.

[0119] Step S214 specifically includes: performing Fourier transform, spectral processing and feature extraction on the audio data processed in step S213 to convert the audio data processed in step S213 into a spectrum for feature comparison; performing cross-correlation calculation on the audio data processed in step S213 and the preset audio data including the spectral features of logging sounds.

[0120] S215: Compare the spectral analysis result of step S214 with the logging sound spectral features set in step S211 to determine whether the audio data collected in step S212 meets the logging sound spectral feature conditions;

[0121] Compare the cross-correlation calculation result of step S214 with the logging sound similarity threshold set in step S211 to determine whether the audio data collected in step S212 meets the logging sound similarity conditions;

[0122] In this embodiment, if the cross-correlation calculation result of step S214 is greater than the logging sound similarity threshold set in step S211, it is determined that the audio data collected in step S212 meets the logging sound similarity conditions; if the spectral analysis result of step S214 includes the logging sound spectral features set in step S211, it is determined that the audio data collected in step S212 meets the logging sound spectral feature conditions.

[0123] S216: Determine whether the audio collected in step S12 is logging audio according to the judgment result of step S215;

[0124] When the audio data collected in step S212 meets the logging sound spectrum feature condition and the logging and sound similarity condition of step S215, it is determined that the audio data collected in step S212 is logging audio;

[0125] When the audio data collected in step S212 does not meet the logging sound spectrum feature condition and / or the logging sound similarity condition of step S215, jump to step S212;

[0126] In this embodiment, when the audio data collected in step S212 meets both the logging sound spectrum feature condition and the logging and sound similarity condition, it is determined that the audio data collected in step S212 is logging audio; otherwise, jump to step S212 to re-collect audio data.

[0127] S217: Accumulate the number of times of determining whether it is logging audio in step S216 to a preset determination number; in order to reduce the misjudgment probability of illegal logging behavior, it is necessary to determine the illegal logging behavior based on multiple logging audio.

[0128] S218: Determine whether the accumulated number of times determined as logging audio in the preset determination number of step S217 reaches the preset number threshold;

[0129] S219: If the accumulated number of times determined as logging audio reaches the preset number threshold, it is determined that an illegal logging behavior is detected; if the accumulated number of times determined as logging audio does not reach the preset number threshold, initialize the accumulated number of times in step S217, re-count, and jump to step S212 to re-collect audio data.

[0130] The fire detection method in step S2 includes thermal imaging detection, such as Figure 4 As shown, the thermal imaging detection of fire includes:

[0131] S221: Initialize and set parameters for the microcontroller and infrared imaging sensor of the thermal imaging detection, and the parameter setting includes a preset temperature threshold;

[0132] The initialization settings of the infrared imaging sensor include setting the acquisition frame rate and acquisition mode. It should be noted that a higher frame rate may bring greater noise, so an appropriate frame rate should be selected according to the actual application scenario. In this embodiment, the microcontroller uses the STM32F411 chip as the processor, the infrared imaging sensor uses the MLX90640, and the acquisition mode of the infrared imaging sensor MLX90640 is set to the chessboard mode.

[0133] S222: Use the infrared imaging sensor in step S221 to collect data and generate an image. In this embodiment, the image resolution of the MLX90640 infrared imaging sensor is 32x24. In the checkerboard mode, the infrared imaging sensor MLX90640 measures half of the pixel points each time, and these pixel points are staggered in a checkerboard pattern. After collecting twice and stitching them together, a complete image with a resolution of 32x24 (768 pixel points) is obtained.

[0134] S223: Perform bad pixel detection on the pixel points of the image generated in step S222 and perform averaging processing on the bad pixels.

[0135] The purpose of bad pixel detection is to identify and mark abnormal or unreliable pixel points in the data. These bad pixels may be caused by sensor failures, environmental interference, data transmission errors, etc. Averaging processing is used to reduce the impact of noise and outliers in the data. In this embodiment, there may be up to 4 unusable pixels in each MLX90640 sensor, which is related to the production process of the sensor. These bad pixels are usually recorded in the EEPROM (Electrically Erasable Programmable Read-Only Memory) of the sensor at the factory. By checking the EEPROM (Electrically Erasable Programmable Read-Only Memory) flag bits, the bad pixels can be found. During actual use, in order to obtain more accurate measurement results, it is necessary to read this information in the EEPROM and perform special processing on the possible bad pixels during imaging. A common processing method is to use the average temperature of the adjacent and normal pixel points of the bad pixel to replace the value of the bad pixel, thereby reducing the impact of the bad pixel on the overall temperature measurement result.

[0136] S224: After a preset delay, transmit the corresponding highest temperature value among the pixel points processed in step S223 to the microcontroller in step S221.

[0137] Each pixel point corresponds to a temperature value. Finding the highest temperature value in the image is used for subsequent temperature judgment. In this embodiment, the preset delay is 100 ms, and the found highest temperature value is transmitted once every 100 ms.

[0138] S225: Compare the highest temperature value in step S224 with the preset temperature threshold in step S221.

[0139] S226: When the highest temperature value is greater than the preset temperature threshold, it is determined that a fire has occurred in the data acquisition area in step S222.

[0140] When the highest temperature value is not greater than the preset temperature value, jump to step S222 to re-collect data and generate an image.

[0141] To further improve the effectiveness of fire detection, in addition to using thermal imaging to detect fires, the fire detection in step S2 also includes smoke alarm to detect fires, and the smoke alarm to detect fires includes:

[0142] S231: The smoke sensor collects smoke information;

[0143] S232: Count the number of alarms of the smoke sensor;

[0144] S233: When the number of alarms of the smoke sensor exceeds the set threshold, it is determined that a fire has occurred in the acquisition area of the smoke alarm detection.

[0145] In step S3, according to Figure 5 and Figure 6 the sound source localization and navigation method shown, driving the mobile mechanism to move to the illegal logging location includes:

[0146] S31: Perform sound source localization according to the sound source localization method;

[0147] S32: Drive the mobile mechanism to move to the illegal logging location according to the sound source localization in step S31 combined with the sound source navigation method;

[0148] Step S31 includes:

[0149] S311: Calculate the time difference of arrival of multiple sound source receivers respectively;

[0150] S312: Perform sound source localization according to the time difference of arrival calculated in step S311, the sound propagation speed, and the distance between the sound source receivers;

[0151] In this embodiment, four MAX9814 sound sensors are installed at the ends of a cross-shaped bracket to form a microphone array. Since the time for sound waves to reach each sensor is different, the distance from the sound source to each sound sensor can be calculated by calculating these time differences of arrival, and then the position of the sound source can be determined. Calculate the time differences of arrival between the four MAX9814 sound sensors respectively, and use the principle of calculating the sound propagation distance with the known time differences of arrival and the sound propagation speed in the air, and use these known data for triangulation or other geometric localization methods to calculate the position of the sound source.

[0152] As Figure 5 shown, the method for calculating the time difference of arrival of each sound source receiver in step S311 includes:

[0153] S3111: Sample two groups of sound source data using an analog-to-digital converter;

[0154] In this embodiment, the analog-to-digital converter of each sound source receiver needs to synchronously collect these two groups of discretized sound source data. The synchronous sampling can be achieved by using a common clock signal or a synchronous trigger signal.

[0155] S3112: Group the sound source data sampled in step S3111 and perform a fast Fourier transform (FFT).

[0156] This step will transform the two sets of discretized sound source data from the time domain to the frequency domain.

[0157] S3113: Perform conjugate processing on one set of the data after the fast Fourier transform (FFT) in step S3112.

[0158] S3114: Multiply the data after the conjugate processing in step S3113 by the other set of data.

[0159] S3115: Perform an inverse fast Fourier transform (IFFT) on the multiplication result in step S3114 to obtain the cross-correlation function of the two sets of sound source data.

[0160] S3116: Record the peak subscript of the cross-correlation function in step S3115.

[0161] In the cross-correlation function, find the position of the maximum value, i.e., the peak. This peak corresponds to the maximum correlation between the two sets of signals. Record the position (subscript) of the peak in the cross-correlation function. This position represents the time delay or time difference of arrival between the two sets of signals.

[0162] S3117: Convert the peak subscript in step S3116 to time to obtain the time difference of arrival.

[0163] As shown in the sound source navigation method of Figure 6 , step S32 includes:

[0164] S321: Determine the target forward direction and target forward distance of the mobile mechanism according to the current position of the mobile mechanism and the sound source localization obtained in step S31.

[0165] S322: Determine the current heading angle and moving speed according to the distance from surrounding obstacles, the target forward direction, and the target forward distance, in combination with the PID algorithm.

[0166] In this embodiment, laser ranging is used to detect obstacles in real time. During the driving process of the mobile mechanism, obstacles are detected in real time. When the distance to the obstacle in front is within the preset distance threshold, the mobile mechanism adjusts the current heading angle and moving speed.

[0167] The PID algorithm (Proportional-Integral-Derivative algorithm) includes the control of the steering loop and the speed loop. The PID algorithm adjusts the control input by controlling the steering and speed to reduce the system error, thereby driving the mobile mechanism to move to the illegal logging location.

[0168] In the application of tracking the sound source position, the steering ring is responsible for controlling the steering of the tracking device so that the device can point in the direction of the sound source. This is usually achieved by adjusting the differential rotation of the left and right wheels.

[0169] Determine the target direction: The sound source positioning obtained in step S31 determines the position and direction of the sound source relative to the mobile mechanism.

[0170] Calculate the error: Compare the current direction of the mobile mechanism with the target direction and calculate the course angle error.

[0171] Apply the PID algorithm: Use the course angle error as the input of the PID algorithm to calculate the control output (such as a PWM signal) for adjusting the current course angle of the mobile mechanism.

[0172] The speed loop is responsible for controlling the forward and backward travel speed of the mobile mechanism to ensure that the mobile mechanism can approach the sound source quickly and stably.

[0173] Determine the target speed: Determine the target moving speed according to the distance between the mobile mechanism and the sound source positioning obtained in step S31 and the desired moving speed.

[0174] Calculate the speed error: Compare the current moving speed of the mobile mechanism with the target moving speed and calculate the speed error.

[0175] Apply the PID algorithm: Use the speed error as the input of the PID algorithm to calculate the control output (such as a motor drive signal) for adjusting the moving speed of the mobile mechanism.

[0176] S223: Loop and execute steps S321 and S322 until the mobile mechanism moves to the illegal logging location.

[0177] Embodiment 2:

[0178] Based on the same inventive concept as Embodiment 1, as Figure 2 shown, this embodiment introduces a forest security patrol system for the forest security patrol method described in Embodiment 1. The forest security patrol system includes a logging detection module, a fire detection module, a sound source positioning module, a sound source navigation module, and a voice broadcast module;

[0179] The logging detection module is used to detect illegal logging behavior according to the logging detection method;

[0180] The fire detection module is used to detect fires according to the fire detection method;

[0181] The sound source positioning module is used to perform sound source positioning on the illegal logging location after the logging detection module detects illegal logging behavior;

[0182] The sound source navigation module is used to drive the mobile mechanism to move to the illegal logging location determined by the sound source positioning module;

[0183] The voice broadcast module is used to broadcast corresponding voices according to the security inspection situation. When the logging detection module detects a fire, the voice broadcast module broadcasts a fire warning; when the mobile mechanism moves to the illegal logging location, the voice broadcast module broadcasts to drive away the illegal loggers.

[0184] In addition to the above main functional modules for security inspection, the forest security inspection system of this embodiment further includes a power supply module, a communication module, and an image transmission module;

[0185] The power supply module is used to supply power to the forest security inspection system and the mobile mechanism;

[0186] The communication module is used for communication between the forest security inspection system and the control end of the forest security inspection system. The communication module is signal-connected to the control end of the forest security inspection system, and the communication module is respectively connected to the logging detection module, the fire detection module, the sound source positioning module, the sound source navigation module, the voice broadcast module, the power supply module, and the image transmission module;

[0187] The image transmission module is used to store the image information during security inspection and upload the stored image information to the control end of the forest security inspection system. When the fire detection module detects a fire, the image transmission module uploads the fire image information; when the mobile mechanism moves to the illegal logging location, the image transmission module uploads the illegal logging image information;

[0188] The image transmission module is connected with a camera to transmit the inspection picture or video to the human-computer interaction interface of the control end of the forest security inspection system in real time, facilitating the management personnel to view and monitor the surrounding environment of the inspection in real time.

[0189] The fire image information includes the fire scene image and the fire thermal imaging image. The generation of the fire thermal imaging image includes: transmitting the thermal imaging image detected by the fire detection module after bilinear interpolation processing to the image transmission module. The fire scene image includes the environmental picture of the fire thermal imaging image data acquisition area.

[0190] The control end of the forest security inspection system includes a control end human-computer interaction interface, and the control end human-computer interaction interface includes a control page and a data page; in this embodiment, the control end human-computer interaction interface is an APP.

[0191] The control page includes alarm information display, remote control, and manual broadcast issuance; Figure 7 This is a schematic diagram of the display of the control page of this embodiment.

[0192] The alarms displayed in the alarm information are divided into illegal logging alarms and fire alarms. The information displayed for illegal logging alarms includes illegal logging location information and illegal logging image information, and the information displayed for fire alarms includes fire location information and fire image information.

[0193] The remote control is used to remotely control the movement of the mobile mechanism and call to view the security inspection scene image; the movement of the mobile mechanism includes forward, backward, left turn, right turn and stop movement, and the security inspection scene image includes the historical image and real-time image of the security inspection scene;

[0194] Manual broadcast is used to manually send voice broadcasts to the forest security patrol system. The voice broadcasts include driving away illegal loggers and fire warnings, or the voice broadcasts include driving away illegal loggers, fire warnings and customized voice content. The customized voice content is customized by the management personnel. According to different applicable scenarios, the customized voice content includes forest protection slogans, search and rescue broadcasts, bird-repelling audio, songs and other forms. Manual alarm also includes a refresh button.

[0195] The data pages are used to:

[0196] The image displays the location information of the mobile mechanism on the map, and sets or changes the security inspection route;

[0197] or,

[0198] The image displays the location information of the mobile mechanism on the map, and sets or changes the security inspection route;

[0199] The image display of the positioning information of the mobile mechanism in the map includes: enlarging or reducing the image display area of ​​the mobile mechanism in the map, such as Figure 8 As shown, the manager can zoom in or out the image display area by touching and moving two fingers on the touch screen to view more specific positioning information, or zoom in or out the image display area by using the plus sign or minus sign in the lower right corner of the interface;

[0200] The security inspection route includes several routes, and the setting or changing of the security inspection route includes:

[0201] Set or change the starting point, end point, start time, start time and stop time of each security inspection route;

[0202] After setting or changing a security inspection route, the mobile mechanism stops the inspection and returns to the preset starting point or starts the next security inspection route;

[0203] Set or change the execution order of security inspection routes when there are multiple security inspection routes.

[0204] After the manual operation of the control page is completed, the management personnel can, through the settings on the data page, make the mobile mechanism return to the original security inspection route and automatically continue the security inspection of the remaining route, or automatically conduct the security inspection according to the set new route.

[0205] In a specific embodiment, as Figure 2 shown, the forest security inspection system of the present invention is mounted on a mobile mechanism, and the mobile mechanism is an inspection vehicle. To adapt to the movement in the forest terrain, the inspection vehicle includes a crawler chassis; the forest security inspection system is mounted on the crawler chassis; the main control board of the forest security inspection system uses the STM32F407 chip as the microprocessor, and the main control board is connected to each module of the forest security inspection system to implement the forest security inspection method.

[0206] The fire detection module includes a thermal imaging detection component and / or a smoke detection component.

[0207] To ensure the stability of the thermal imaging detection data acquisition, the thermal imaging detection module is mounted on a servo motor. A servo motor is a motor that can precisely control the angle and position. The thermal imaging detection module can be connected to the output shaft of the servo motor through a bracket or a fixing device; when the servo motor rotates, the thermal imaging module will also rotate accordingly, so as to realize the observation in different directions; the thermal imaging detection component includes a microcontroller with the STM32F411 chip as the processor and an infrared thermal imaging sensor MLX90640. In addition to uploading the fire thermal imaging image to the forest security inspection system, the thermal imaging detection component is also equipped with an LCD screen as the display carrier of the thermal imaging image of the inspection vehicle. To improve the image quality of the thermal imaging image display and realize the conversion of low-resolution temperature data into high-resolution data, in this embodiment, the 24*32 image collected by the infrared thermal imaging sensor MLX90640 is processed by bilinear interpolation to a 120*160 image, and the image after bilinear interpolation processing is subjected to data mirroring, displayed on the LCD screen and stored in the local storage module connected to the main control board for data storage. Bilinear interpolation processing is to perform linear interpolation once in two directions (usually the X and Y directions) to obtain the pixel value of the target point, so as to obtain a smooth and continuous image display effect. Similarly, the fire thermal imaging image uploaded to the image transmission module also undergoes bilinear interpolation processing. The image transmission module is connected to a camera, and the camera transmits the inspection picture or video in real time to the human-computer interaction interface at the control end of the forest security inspection system. The camera can rotate the angle to realize the observation in different directions, and the image storage of the camera also includes local storage.

[0208] The sound source localization module includes a microphone array.

[0209] The sound source navigation module includes a GPS positioning component, a ranging component, and an attitude detection component; the ranging component is used for laser ranging to detect obstacles; the attitude detection component includes an MPU6050 sensor, and the MPU6050 is a high-performance and high-precision six-axis motion tracking sensor, and the MPU6050 sensor is used for the attitude and speed control of the inspection vehicle during movement;

[0210] The communication module includes a Fibocom L610, and the Fibocom L610 is a high-performance LTE Cat 1 bis wireless communication module; the Fibocom L610 module supports the transmission of various data types, including text, numerical values, pictures, videos, audio, as well as binary and sensor data, etc. This enables the Fibocom L610 module to have broad application prospects in multiple fields such as the Internet of Things, video surveillance, and remote calls.

[0211] The power supply module includes 5V and 12V power supplies; the main control board, the motor drive board, and the image transmission module are powered by the 12V power supply, and the servo is powered by the 5V power supply.

[0212] After the forest security inspection system is started, initialization operations are performed on each module; GPS information is collected in real time; movement is started, and the inspection vehicle starts security inspections according to the preset security inspection route; the microphone array collects audio data in real time, and detects illegal logging behavior through the logging detection method. If illegal logging behavior is detected, it will go to the illegal logging location where the sound source is located through the sound source positioning method and the sound source navigation method; when it arrives at the illegal logging location, it will broadcast a voice to drive away the illegal loggers and report the alarm information to the APP; the thermal imaging detects the surrounding temperature in real time, and the smoke sensor monitors the smoke information in real time. If it is judged that a fire has occurred through the fire detection method, the alarm information will be immediately reported to the APP; the APP monitors the road conditions of the inspection vehicle in real time. If it receives the pop-up vibration and the alarm coordinate information, the management personnel will immediately make a response; the management personnel on the APP side can see the positioning information of the inspection vehicle on the map and the security inspection site image in real time; the management personnel on the APP side can set the security inspection route on the data page, so that the inspection vehicle conducts security inspections according to the set route, and can also remotely control the inspection vehicle to work and call up and view the historical security inspection site images on the control page temporarily.

[0213] The mobile mechanism of the present invention can be an inspection vehicle or other mobile mechanisms such as an unmanned aerial vehicle. The forest security inspection system of the present invention can conduct security inspections on-site with inspection personnel, or can be remotely monitored by management personnel for security inspections. It has high flexibility. The security inspection personnel do not have to directly contact the security inspection environment, avoiding management personnel directly contacting the police situation. While being able to complete daily security inspection tasks, it improves the protection of the personal safety of management personnel.

[0214] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memory, CD-ROM, optical memory, etc.) that contain computer-usable program code.

[0215] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0216] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including instruction means, and the instruction means implement the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0217] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Therefore, the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one Figure 1 flow or multiple flows and / or blocks Figure 1 or multiple blocks.

[0218] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A forest security inspection method, characterized in that: Use a mobile mechanism equipped with a forest security inspection system for safety inspections, including: S1: Preprocessing the forest security inspection system, wherein the preprocessing includes setting a security inspection route; S2: The mobile mechanism performs security inspection according to the route set in step S1, wherein the security inspection includes logging inspection and fire inspection; S3: When illegal logging is detected in step S2, the mobile mechanism is driven to the illegal logging location according to the sound source positioning and navigation method, and voice broadcast is performed to drive away the illegal loggers and upload illegal logging information to the control end of the forest security inspection system, wherein the illegal logging information includes illegal logging location information and illegal logging image information; When a fire is detected in step S2, a voice fire warning is broadcast and fire information is uploaded to the control end of the forest security patrol system, wherein the fire information includes fire location information and fire image information.

2. The forest security inspection method according to claim 1, characterized in that: Also includes: S4: The control end of the forest security inspection system performs alarm processing on the illegal logging information and / or fire information reported in step S3. After the processing is completed, the mobile mechanism returns to the original security inspection route to continue the security inspection of the remaining routes or performs security inspection according to the set new route; S5: When the security inspection route set in step S1 or step S4 is completed, the mobile mechanism returns to the preset starting point or performs the next security inspection.

3. The forest security inspection method according to claim 1 or 2, characterized in that: The logging detection method of step S2 includes: S211: setting the spectral characteristics of logging sounds and the similarity threshold of logging sounds according to the pre-experimental results; S212: During the security inspection, audio data of a preset duration is collected; S213: pre-processing the audio data collected in step S212; S214: performing feature analysis on the audio data processed in step S213, wherein the feature analysis includes spectrum analysis and cross-correlation calculation; S215: Compare the spectrum analysis result of step S214 with the spectrum characteristics of the logging sound set in step S211 to determine whether the audio data collected in step S212 meets the spectrum characteristics of the logging sound; Compare the cross-correlation calculation result of step S214 with the logging sound similarity threshold set in step S211 to determine whether the audio data collected in step S212 meets the logging sound similarity condition; S216: Determine whether the audio collected in step S12 is lumberjack audio according to the judgment result of step S215; When the audio data collected in step S212 meets the wood-cutting sound spectrum characteristic condition and the wood-cutting sound similarity condition in step S215, it is determined that the audio data collected in step S212 is wood-cutting audio; When the audio data collected in step S212 does not meet the logging sound spectrum feature condition and / or logging sound similarity condition in step S215, then jump to step S212; S217: accumulating the number of times of determining whether the audio is logging audio in step S216 to a preset number of determinations; S218: determining whether the cumulative number of times the audio is determined to be felling audio in the preset number of determinations in step S217 reaches a preset number threshold; S219: If it is determined that the cumulative number of logging audios reaches the preset number threshold, it is determined that illegal logging is detected; if it is determined that the cumulative number of logging audios does not reach the preset number threshold, the cumulative number of step S217 is initialized and jump to step S212.

4. The forest security inspection method according to claim 1 or 2, characterized in that: The fire detection method of step S2 includes detecting fire by thermal imaging; The thermal imaging fire detection includes: S221: Initializing and setting parameters of a microcontroller and an infrared imaging sensor for thermal imaging detection, wherein the parameter setting includes a preset temperature threshold; S222: using the infrared imaging sensor of step S221 to collect data and generate an image; S223: performing bad pixel detection on the image pixels generated in step S222 and performing averaging processing on the bad pixels; S224: after a preset delay, transmitting the corresponding highest temperature value of the pixel point processed in step S223 to the microcontroller in step S221; S225: Compare the highest temperature value of step S224 with the preset temperature threshold of step S221; S226: When the highest temperature value is greater than the preset temperature threshold, it is determined that a fire occurs in the data collection area of ​​step S222; When the highest temperature value is not greater than the preset temperature value, jump to step S222.

5. The forest security inspection method according to claim 4, characterized in that: The fire detection in step S2 also includes smoke alarm fire detection, and the smoke alarm fire detection includes: S231: The smoke sensor collects smoke information; S232: Counting the number of alarms of the smoke sensor; S233: When the number of smoke sensor alarms exceeds a set threshold, it is determined that a fire has occurred in the smoke alarm detection collection area.

6. The forest security inspection method according to claim 1 or 2, characterized in that: In step S3, driving the mobile mechanism to move to the illegal logging location according to the sound source positioning and navigation method includes: S31: localizing the sound source according to the sound source localization method; S32: driving the mobile mechanism to move to the illegal logging location according to the sound source positioning combined with the sound source navigation method in step S31; Step S31 includes: S311: Calculate the arrival time difference of multiple sound source receivers respectively; S312: localizing the sound source according to the arrival time difference, sound propagation speed, and distance between the sound source and the receiver calculated in step S311; The method for calculating the arrival time difference of each sound source receiver in step S311 includes: S3111: sampling two sets of sound source data using an analog-to-digital converter; S3112: grouping the sound source data sampled in step S3111 and performing fast Fourier transform; S3113: performing conjugate processing on a group of data after fast Fourier transformation in step S3112; S3114: multiplying the data after the conjugate processing in step S3113 by another set of data; S3115: Performing an inverse fast Fourier transform on the multiplication result of step S3114 to obtain a cross-correlation function of the two sets of sound source data; S3116: Record the peak subscript of the cross-correlation function in step S3115; S3117: Convert the peak subscript of step S3116 into time to obtain the arrival time difference.

7. The forest security inspection method according to claim 6, characterized in that: Step S32 includes: S321: Determine the target moving direction and target moving distance of the moving mechanism according to the current position of the moving mechanism and the sound source positioning obtained in step S31; S322: Determine the current heading angle and moving speed based on the distance to surrounding obstacles, the target moving direction and the target moving distance in combination with the PID algorithm; S223: Execute steps S321 and S322 in a loop until the moving mechanism moves to the illegal logging site.

8. A forest security inspection system, characterized in that: Used in the forest security inspection method according to any one of claims 1 to 7, The forest security inspection system includes a logging detection module, a fire detection module, a sound source positioning module, a sound source navigation module, and a voice broadcast module; The logging detection module is used to detect illegal logging according to the logging detection method; The fire detection module is used to detect fire according to the fire detection method; The sound source positioning module is used to locate the sound source of the illegal logging after the logging detection module detects the illegal logging behavior; The sound source navigation module is used to drive the mobile mechanism to move to the illegal logging location determined by the sound source positioning module; The voice broadcast module is used to broadcast corresponding voices according to the security inspection situation. When the logging detection module detects a fire, the voice broadcast module broadcasts a fire warning; when the mobile mechanism moves to the illegal logging site, the voice broadcast module broadcasts a voice to drive away the illegal loggers.

9. The forest security inspection system according to claim 8, characterized in that: It also includes a power module, a communication module and an image transmission module; The power module is used to power the forest security patrol system and the mobile mechanism; The communication module is used for communication between the forest security patrol system and the control end of the forest security patrol system. The communication module signal is connected to the control end of the forest security patrol system. The communication module is respectively connected to the logging detection module, the fire detection module, the sound source positioning module, the sound source navigation module, the voice broadcast module, the power supply module and the image transmission module; The image transmission module is used to store image information during security inspection and upload the stored image information to the control end of the forest security inspection system. When the fire detection module detects a fire, the image transmission module uploads the fire image information; when the mobile mechanism moves to the illegal logging site, the image transmission module uploads the illegal logging image information; The fire image information includes a fire scene image and a fire thermal imaging image. The generation of the fire thermal imaging image includes: transmitting the thermal imaging image detected by the fire detection module to the image transmission module after bilinear difference processing.

10. The forest security inspection system according to claim 9, characterized in that: The control end of the forest security patrol system includes a control end human-computer interaction interface, and the control end human-computer interaction interface includes a control page and a data page; The control page includes alarm information display, remote control and manual broadcasting; The alarms displayed in the alarm information are divided into illegal logging alarms and fire alarms. The information displayed for illegal logging alarms includes illegal logging location information and illegal logging image information, and the information displayed for fire alarms includes fire location information and fire image information. The remote control is used to remotely control the movement of the mobile mechanism and call to view the security inspection scene image; the movement of the mobile mechanism includes forward, backward, left turn, right turn and stop movement, and the security inspection scene image includes the historical image and real-time image of the security inspection scene; Manual broadcast is used to manually send voice broadcast to the forest security patrol system, the voice broadcast includes driving away illegal loggers and fire warning, or the voice broadcast includes driving away illegal loggers, fire warning and custom voice content; The data pages are used to: The image displays the location information of the mobile mechanism on the map, and sets or changes the security inspection route; or, The image displays the location information of the mobile mechanism on the map, and sets or changes the security inspection route; The image displaying the positioning information of the mobile mechanism in the map includes: enlarging or reducing the image display area of ​​the mobile mechanism in the map; The security inspection route includes several routes, and the setting or changing of the security inspection route includes: Set or change the starting point, end point, start time, start time and stop time of each security inspection route; After setting or changing a security inspection route, the mobile mechanism stops the inspection and returns to the preset starting point or starts the next security inspection route; Set or change the execution order of security inspection routes when there are multiple security inspection routes.

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