Farmland video monitoring-based ad hoc network decoder and data transmission method

Abstract

The invention discloses a farmland video monitoring-based ad hoc network decoder and a data transmission method, and relates to the technical field of communication and agricultural automation, the farmland video monitoring-based ad hoc network decoder comprises a dual-core processor module which adopts a dual-core ARMCortex-A7 architecture, a first core executes H.265 video coding and decoding, a second core processes valve state data packaging, and dual cores exchange data through a shared memory address; the Wi-SUN communication module adopts a wi-sun communication module meeting the iee802.15. 4 g standard, wireless communication based on a wi-sun protocol supports self-adaptive transmission of a dynamic channel bandwidth of 1MHz-2.5 MHz, and a time division multiple access (TDMA) scheduler is arranged in the Wi-SUN communication module; through the wi-sun communication technology, high-speed transmission of video large-flow data in a local area network is achieved, compared with a traditional wireless transmission mode, the transmission speed is increased by several times, seedling condition information and valve opening and closing information can be transmitted to a user in real time, and a basis is provided for timely decision making.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication and agricultural automation, and particularly relates to a self-organizing network decoder based on farmland video monitoring and a data transmission method. BACKGROUND

[0002] In the farmland irrigation system, it is very crucial to grasp the real-time seedling information and accurately monitor the valve opening and closing state. The traditional farmland monitoring method has many drawbacks, for example, manual monitoring is inefficient and cannot provide real-time feedback information. Some existing wireless transmission schemes are prone to slow transmission speed and poor stability when facing video large flow data transmission, and cannot meet the demand of modern agriculture for accurate and efficient irrigation.

[0003] Wi-sun communication technology, as a wireless communication network technology based on IEEE 802.15.4 standard, has the advantages of long-distance communication, high coverage, low power consumption, low cost, high security, good interoperability, high data throughput and low delay, etc., which provides a new possibility for solving the above problems. However, there is no mature scheme to combine wi-sun communication technology with valve controller or valve decoder in the farmland irrigation system to realize high-speed and stable transmission of video large flow data.

[0004] The prior art has the following disadvantages: the existing farmland video monitoring and irrigation control has many disadvantages, for example, the LoRa / ZigBee bandwidth used in current data transmission is insufficient to carry 1080P video stream, and the seedling video and valve state are transmitted separately, which leads to lack of spatio-temporal consistency in irrigation decision-making, multi-path fading caused by farmland metal irrigation pipe network, high video packet loss rate, poor reliability, and lack of online closed loop with cloud AI model, which cannot dynamically adjust the irrigation strategy according to the crop growth.

[0005] The above information disclosed in the background section is only used to enhance the understanding of the background of the present disclosure, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to provide a self-organizing network decoder based on farmland video monitoring and a data transmission method. The present application realizes high-speed transmission of video large flow data in the local area network through wi-sun communication technology, wi-sun self-organizing network and anti-interference capability, and reduces signal interruption and data loss, to solve the problems in the above background technology.

[0007] In order to achieve the above object, the present application provides the following technical scheme: based on farmland video monitoring ad hoc network decoder, including dual-core processor module: using dual-core ARM Cortex-A7 architecture, the first core executes H.265 video codec, and the second core processes valve state data packaging, and the dual-core carries out data exchange through shared memory address; Wi-SUN communication module: using wi-sun communication module conforming to ieee802.15.4g standard, and based on the wireless communication of wi-sun protocol, supporting adaptive transmission of 1MHz-2.5MHz dynamic channel bandwidth, built-in TDMA scheduler; Video acquisition module: using Sony IMX415 sensor, connecting the first core of dual-core processor module to execute H.265 encoder, outputting compressed video stream with timestamp and GPS coordinates of seedling condition area; RS485 interface module: polling valve state every 500ms as a cycle, triggering interrupt and recording timestamp when valve state changes; Storage module: using large-capacity SPI-flash memory, divided into cyclically covered video cache area and non-volatile valve state information area, when the absolute value difference between video frame timestamp and valve state timestamp is less than 50ms, generating space-time synchronization package.

[0008] Optionally, the processing steps of the dual-core processor module are as follows: The first core receives compressed video stream of farmland video monitoring, adds frame priority label according to I / P frame type, and records timestamp of each frame and GPS coordinates of seedling condition area corresponding to each frame image, wherein the timestamp of the first core is ; The second core monitors valve state interrupt signal in real time, records state value and timestamp corresponding to valve ID in combination with valve ID, wherein the timestamp of the second core is ; When the absolute difference between the timestamp of the first core and the timestamp of the second core is less than fifty milliseconds, that is , the second core sends synchronization request to the first core; The dual-core processor module maintains timestamp register in shared memory, the timestamp register is written by the timestamp of the first core when video frame acquisition is completed , and the timestamp of the second core when valve state change interrupt arrives , to realize the judgment of space-time synchronization; The first core receives and responds to the synchronization request of the second core, and packs the current video frame and valve state into space-time synchronization package containing common timestamp .

[0009] Optionally, the data exchange step of the shared memory is as follows: A synchronization flag register is set in the shared memory area, and the shared memory address is 0xFFFF0000-0xFFFF1FFF; The second core sets the byte low bit Bit0 of the register when writing a synchronization request; The first core starts the time-space package after reading the byte low bit Bit0, and resets the byte low bit Bit0.

[0010] Wi-SUN communication module: adopt wi-sun communication module conforming to ieee802.15.4g standard, and support adaptive transmission of 1MHz-2.5MHz dynamic channel bandwidth based on wi-sun protocol, and built-in time division multiple access TDMA scheduler.

[0011] Optionally, the step of supporting adaptive transmission of the Wi-SUN communication module is as follows: The Wi-SUN communication module detects the received signal strength indication RSSI in real time, and when RSSI<-85dBm, it switches to 2.5MHz wide channel, and automatically shortens the time division multiple access TDMA time slot length, i.e. shortens the TDMA time slot length from 10ms to 4ms, for maintaining the real-time of video frame and reducing the channel occupation conflict probability; Select a relay node with a load rate less than 60% as the next hop based on the neighbor node load table, wherein the neighbor node load table is updated in the form of a sliding window in memory, and the window length is 10s, and the update frequency is 1Hz, for dynamically reflecting the instantaneous interference caused by metal irrigation facilities in the farmland environment; According to the time division multiple access TDMA mechanism, the TDMA mechanism needs to allocate time slots to meet the requirements of video I frame being greater than valve state being greater than video P frame being greater than video B frame.

[0012] Optionally, the collection step of the video collection module is as follows: Sony IMX415 sensor collects raw video with resolution of 1080P and sampling rate of 25-30fps; The first core in the dual-core processor module controls the H.265 compression code rate at 1.2Mbps, to ensure that the video time slot utilization rate is ≤75% under 2.5MHz channel, so that the original video is compressed to 45%±5% of the original size through H.265 encoding; And add millisecond-level timestamp and seedling region GPS coordinates to each frame of video.

[0013] Optionally, the execution step of the RS485 interface module is as follows: Poll the Modbus-RTU protocol bus connected to the valve controller at a period of every 500ms; When the level jump of the valve state is detected, the hardware interrupt is triggered immediately, and then when the valve state contains a fault code, the second core sends a forced preemption signal to the Wi-SUN communication module immediately, interrupts the current video time slot, and transmits the valve data preferentially; The valve ID and the state value are extracted, and a common timestamp aligned with the time when the interrupt is triggered is attached.

[0014] Optionally, the division step of the storage module is as follows: The physical interface QSPI of the storage module is connected to the dual-core processor module; The storage area of the storage module is divided into a cyclically covered video cache area at 0x0000-0x7FFFFF; The storage area is divided into a non-volatile valve state information area at 0x800000-0x81FFFF; The storage area is divided into a firmware and OTA backup area at 0x820000-0x83FFFF.

[0015] Optionally, the structure of the space-time synchronization packet is composed of a packet header, video data, valve data, and a packet tail, wherein the packet header contains a type identifier 0xFF, a common timestamp , and a GPS coordinate of the growth area, wherein the type identifier 0xFF triggers the receiving end to perform space-time alignment processing; The video data contains I / P frames; The valve data contains a valve ID and a state value corresponding to the valve ID; The packet tail is a CRC32 verification block; The generation steps of the space-time synchronization packet are as follows: When the valve state change occurs within 50ms after the start of video frame collection, the valve data is considered as a same space-time event as the corresponding frame video data, otherwise, the valve data is packaged independently and space-time binding is not performed.

[0016] The data transmission method based on the farmland video monitoring ad hoc network decoder includes the following steps: S1, data acquisition cooperation: after the video acquisition module collects a frame of 1080P image, the first core in the dual-core processor module performs H.265 encoding, and writes the growth area GPS coordinate and timestamp into the packet header; when the RS485 interface module polls the valve state change, the second core in the dual-core processor module encapsulates the valve ID, state value, and timestamp into an emergency flag packet; S2, space-time synchronization packet generation: the second core appends the valve emergency flag packet to the packet header of the same video frame to form a space-time synchronization packet, and delivers it to the Wi-SUN communication module through a ring buffer in shared memory; S3, Wi-SUN adaptive transmission: the Wi-SUN communication module detects the received signal strength indication (RSSI) in real time, and when RSSI < -85dBm, it switches to a 2.5MHz wide channel, selects a relay node with a load rate less than 60% as the next hop by querying the neighbor node load table; S4, receiving end synchronization verification: the receiving end completes pixel-level space-time alignment according to the timestamp in the packet header and the timestamp of the emergency flag packet, and superimposes a valve status icon on the display interface playing the video; when the CRC32 verification fails, the receiving end returns a NACK code to require the sending end to retransmit the last N packets, and N is configured by the user to be between 2-5.

[0017] Optionally, when the receiving end superimposes the valve status icon on the display interface playing the video in step S4, it can superimpose the valve status icon on the display interface playing the video according to the difference between the timestamp of the first core and the current system time Color prompt: When , green is displayed; When , yellow is displayed; When , red is displayed and a local alarm is triggered.

[0018] In the above technical solution, the present application has the following technical effects and advantages: The present application realizes high-speed transmission of video large-flow data in a local area network through wi-sun communication technology, and the transmission speed is improved by several times compared with traditional wireless transmission methods, which can transmit seedling condition information and valve switching information to users in real time, providing a basis for timely decision-making, realizing pixel-level alignment of valve action and seedling video by using a hardware timestamp register, and realizing real-time seedling condition and valve state monitoring, which helps users to adjust irrigation strategies in a timely manner according to actual conditions, realizes precise irrigation, improves water resource utilization efficiency, and promotes the intelligent and modern development of agricultural production; The use of dual-core processors realizes physical isolation of video encoding and decoding and network scheduling, avoids resource contention, and combines TDMA time slot allocation and dynamic channel switching to resist metal interference of the irrigation system, further ensuring the reliable operation of the farmland irrigation system; In addition, efficient video encoding algorithms and data compression algorithms are used to minimize the size of video data and reduce the transmission burden on the premise of ensuring video quality, and a data synchronization mechanism and a verification algorithm are introduced to ensure the accuracy and integrity of video data and valve switching information during data transmission, the sending end adds a timestamp and a verification code in the data, the receiving end sorts and synchronizes the data according to the timestamp, and the verification code is used to verify whether the data has errors during transmission, thereby improving the stability and reliability of data transmission. BRIEF DESCRIPTION OF DRAWINGS

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0020] Figure 1 This is a block diagram of the module structure of the self-organizing network decoder for farmland video surveillance based on the present invention.

[0021] Figure 2 This is a flowchart of the data transmission method based on the self-organizing network decoder for farmland video surveillance according to the present invention. Detailed Implementation

[0022] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0023] Example 1 This invention provides, for example Figure 1 The decoder shown is based on a self-organizing network for farmland video surveillance, including Dual-core processor module: Adopting a dual-core ARM Cortex-A7 architecture, the first core performs H.265 video encoding and decoding, and the second core processes valve status data encapsulation. The two cores exchange data through a shared memory address to achieve physical layer isolation between the video stream and the control stream. Specifically, the processing steps of the dual-core processor module are as follows: The first core receives compressed video streams from farmland video monitoring, adds frame priority markers according to I / P frame type, and records the timestamp of each frame and the GPS coordinates of the crop condition area corresponding to each frame image. The timestamp of the first core is marked as follows: ; The second core monitors the valve status interruption signal in real time, and records the status value and timestamp of the corresponding valve ID based on the valve ID. The timestamp of the second core is marked as follows: ; When the absolute difference between the timestamps of the first core and the second core is less than fifty milliseconds, that is... The second core sends a synchronization request to the first core; The dual-core processor module maintains a timestamp register in shared memory. The timestamp register is written to the first core by the first core when video frame acquisition is completed. The timestamp is written to the second core when the valve state change interruption occurs. To achieve the determination of spatiotemporal synchronization; The first core receives and responds to the synchronization request from the second core, packaging the current video frame and valve status into a single file containing a common timestamp. The spacetime synchronization package.

[0024] Specifically, the data exchange steps for shared memory are as follows: Set the synchronization flag register in the shared memory area, and the shared memory address is 0xFFFF0000-0xFFFF1FFF; When the second core writes a synchronization request, it sets the least significant bit (Bit 0) of the register. After the first core reads the least significant bit (Bit0) of the byte, it starts the empty packet encapsulation and completes the reset of the least significant bit (Bit0) of the byte.

[0025] Wi-SUN communication module: It adopts the Wi-SUN communication module that conforms to the IEEE 802.15.4g standard, and supports adaptive transmission with dynamic channel bandwidth of 1MHz-2.5MHz based on the Wi-SUN protocol. It has a built-in Time Division Multiple Access (TDMA) scheduler and pre-allocates 80% of the TDMA time slots to video data. Specifically, the steps for Wi-SUN communication modules to support adaptive transmission are as follows: The Wi-SUN communication module detects the Received Signal Strength Indicator (RSSI) in real time. When RSSI < -85dBm, it switches to a 2.5MHz wide channel and automatically shortens the Time Division Multiple Access (TDMA) time slot length, reducing the TDMA time slot length from 10ms to 4ms to maintain the real-time performance of video frames and reduce the probability of channel occupancy conflicts. The relay node with a load rate of less than 60% is selected as the next hop based on the neighbor node load table. The neighbor node load table is updated in memory in the form of a sliding window with a window length of 10 seconds and an update frequency of 1 Hz, which is used to dynamically reflect the instantaneous interference caused by metal irrigation facilities in the farmland environment. When allocating time slots using the Time Division Multiple Access (TDMA) mechanism, the TDMA mechanism must ensure that the time slot allocation satisfies the following conditions: video I-frame > valve state > video P-frame > video B-frame.

[0026] Specifically, the transmission strategy of the wi-sun communication module is as follows: The time-space synchronization packet forcibly preempts I-frame time slot transmission or directly occupies the pre-allocated video time slot; The independent valve package preempts the current time slot and inserts a high-priority marker; Data packets containing valve fault codes preempt all low-priority time slots; Forward error correction (FEC) codes are added to the B-frames of the video and then retransmitted during idle time slots.

[0027] Video acquisition module: It adopts a Sony IMX415 sensor, which is connected to the first core of the dual-core processor module to execute an H.265 encoder and output a compressed video stream with timestamps and GPS coordinates of the seedling area; Specifically, the video capture module's capture steps are as follows: The Sony IMX415 sensor captures raw video at a resolution of 1080P and a sampling rate of 25-30fps. The first core in the dual-core processor module controls the H.265 compressed bitrate at 1.2Mbps to ensure that the video slot utilization rate is ≤75% under the 2.5MHz channel, so that the original video is compressed to 45%±5% of its original size through H.265 encoding; And add millisecond-level timestamps and GPS coordinates of the crop growth area to each frame of video; The compressed data is transmitted to the dual-core processor module according to the preset segmentation rules.

[0028] RS485 interface module: Polls the valve status every 500ms, triggers an interrupt and records the timestamp when the valve status changes; Specifically, the execution steps of the RS485 interface module are as follows: The Modbus-RTU protocol bus connected to the valve controller is polled periodically every 500ms. When a level change in the valve status is detected, a hardware interrupt is immediately triggered. When a fault code is detected in the valve status, the second core immediately sends a forced preemption signal to the Wi-SUN communication module, interrupting the current video time slot and prioritizing the transmission of valve data. Extract the valve ID and status value, and append a common timestamp aligned with the interrupt trigger time.

[0029] Storage module: It adopts a large-capacity SPI-flash memory, which is divided into a video buffer area with cyclic coverage and a non-volatile valve status information area. When the absolute difference between the video frame timestamp and the valve status timestamp is less than 50ms through the second verification, a time-space synchronization packet is generated to prevent data loss due to network interruption.

[0030] Specifically, the steps for dividing the storage module are as follows: The storage module's physical interface, QSPI, connects to the dual-core processor module; The storage area of ​​the storage module is divided into a circularly overwritten video buffer from 0x0000 to 0x7FFFFF; The storage area from 0x800000 to 0x81FFFF is divided into a non-volatile valve status information area; The storage area from 0x820000 to 0x83FFFF is divided into firmware and OTA backup areas.

[0031] Specifically, the spatiotemporal synchronization packet consists of a header, video data, valve data, and a trailer. The header includes a type identifier (0xFF) and a common timestamp. GPS coordinates of the seedling area, where the type identifier 0xFF triggers the receiver to perform spatiotemporal alignment processing; Video data includes I / P frames; Valve data includes the valve ID and the status value of the corresponding valve ID; The packet ends with a CRC32 verification block; The steps for generating a spacetime synchronization package are as follows: If a valve state change occurs within 50ms after the start of video frame acquisition, the valve data is considered to be the same spatiotemporal event as the corresponding frame video data; otherwise, the valve data is packaged independently and spatiotemporal binding is not performed.

[0032] Example 2 This invention provides, for example Figure 2 The data transmission method based on the farmland video surveillance self-organizing network decoder shown includes the following steps: S1. Data Acquisition Collaboration: After the video acquisition module acquires a 1080P image frame, the first core of the dual-core processor module performs H.265 encoding and writes the GPS coordinates and timestamp of the seedling area into the packet header. When the RS485 interface module polls for a change in valve status, the second core of the dual-core processor module encapsulates the valve ID, status value and timestamp into an emergency flag packet. S2, Spatiotemporal Synchronization Packet Generation: The second core appends the valve emergency flag packet to the header of the same video frame to form a spatiotemporal synchronization packet, and passes it to the Wi-SUN communication module through a circular buffer in shared memory; S3, Wi-SUN Adaptive Transmission: The Wi-SUN communication module detects the received signal strength indicator RSSI in real time. When RSSI < -85dBm, it switches to the 2.5MHz wide channel and selects a relay node with a load rate < 60% as the next hop by querying the neighbor node load table. S4. Receiver Synchronization Verification: The receiver performs pixel-level spatiotemporal alignment based on the timestamp in the packet header and the timestamp of the emergency flag packet, and overlays the valve status icon on the video playback display interface. When the CRC32 verification fails, the receiver returns a NACK code to request the sender to retransmit the last N packets, and N is configured by the user between 2 and 5.

[0033] Specifically, in step S4, when the receiving end overlays the valve status icon on the video playback display interface, it can... The difference between the timestamp of the first core and the current system time Provide color-coded prompts: when When green is displayed; when When it is yellow, it will be displayed. when When this occurs, a red indicator will be displayed and a local alarm will be triggered.

[0034] Specifically, the collaborative processing steps at the receiving end in step S4 are as follows: Parse the packet header type identifier; if it is 0xFF, extract the timestamp t1. Overlay video frames and valve status icons on the same playback timeline; Verify the CRC32 checksum at the end of the packet; if it fails, return a NACK instruction and the sequence number of the retransmitted packet.

[0035] Specifically, the mechanism by which the NACK code requires the sender to retransmit is as follows: The NACK retransmission mechanism employs an exponential backoff strategy, including an initial retransmission interval of 20 ms, which doubles after each failed retransmission, with a maximum of 3 retransmissions. If all three retransmissions fail, an exception log is recorded in the non-volatile area of ​​the storage module for subsequent offline analysis.

[0036] The data transmission method based on the self-organizing network decoder for farmland video surveillance provided in this embodiment of the invention is implemented by the aforementioned self-organizing network decoder for farmland video surveillance. For details of the specific method and process of the data transmission method based on the self-organizing network decoder for farmland video surveillance, please refer to the aforementioned embodiment based on the self-organizing network decoder for farmland video surveillance, which will not be repeated here.

[0037] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0038] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. A semiconductor medium can be a solid-state drive.

[0039] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0040] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0041] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A decoder based on a self-organizing network for farmland video surveillance, characterized in that: Includes a dual-core processor module: It employs a dual-core ARM Cortex-A7 architecture, with the first core executing H.265 video encoding / decoding and the second core processing valve status data encapsulation. The two cores exchange data via a shared memory address. Wi-SUN communication module: It adopts the Wi-SUN communication module that conforms to the IEEE 802.15.4g standard, and supports adaptive transmission with dynamic channel bandwidth of 1MHz-2.5MHz based on the Wi-SUN protocol. It has a built-in Time Division Multiple Access (TDMA) scheduler. Video acquisition module: It adopts a Sony IMX415 sensor, which is connected to the first core of the dual-core processor module to execute an H.265 encoder and output a compressed video stream with timestamps and GPS coordinates of the seedling area; RS485 interface module: Polls the valve status every 500ms, triggers an interrupt and records the timestamp when the valve status changes; Storage module: It adopts a large-capacity SPI-flash memory, which is divided into a video buffer area with cyclic coverage and a non-volatile valve status information area. When the absolute difference between the video frame timestamp and the valve status timestamp is less than 50ms, a time-space synchronization packet is generated.

2. The decoder based on a self-organizing network for farmland video surveillance according to claim 1, characterized in that, The processing steps of the dual-core processor module are as follows: The first core receives compressed video streams from farmland video monitoring, adds frame priority markers according to I / P frame type, and records the timestamp of each frame and the GPS coordinates of the crop condition area corresponding to each frame image. The timestamp of the first core is marked as follows: ; The second core monitors the valve status interruption signal in real time, and records the status value and timestamp of the corresponding valve ID based on the valve ID. The timestamp of the second core is marked as follows: ; When the absolute difference between the timestamps of the first core and the second core is less than fifty milliseconds, that is... The second core sends a synchronization request to the first core; The dual-core processor module maintains a timestamp register in shared memory. The timestamp register is written to the first core by the first core when video frame acquisition is completed. The timestamp is written to the second core when the valve state change interruption occurs. To achieve the determination of spatiotemporal synchronization; The first core receives and responds to the synchronization request from the second core, packaging the current video frame and valve status into a single file containing a common timestamp. The spacetime synchronization package.

3. The decoder based on a self-organizing network for farmland video surveillance according to claim 2, characterized in that, The data exchange steps for the shared memory are as follows: Set the synchronization flag register in the shared memory area, and the shared memory address is 0xFFFF0000-0xFFFF1FFF; When the second core writes a synchronization request, it sets the least significant bit (Bit 0) of the register. After the first core reads the least significant bit (Bit0) of the byte, it starts the empty packet encapsulation and completes the reset of the least significant bit (Bit0) of the byte. Wi-SUN communication module: It adopts the Wi-SUN communication module that conforms to the IEEE 802.15.4g standard, and supports adaptive transmission with dynamic channel bandwidth of 1MHz-2.5MHz based on the Wi-SUN protocol. It has a built-in Time Division Multiple Access (TDMA) scheduler.

4. The decoder based on a self-organizing network for farmland video surveillance according to claim 3, characterized in that, The steps for the Wi-SUN communication module to support adaptive transmission are as follows: The Wi-SUN communication module detects the Received Signal Strength Indicator (RSSI) in real time. When RSSI < -85dBm, it switches to a 2.5MHz wide channel and automatically shortens the Time Division Multiple Access (TDMA) time slot length, reducing the TDMA time slot length from 10ms to 4ms to maintain the real-time performance of video frames and reduce the probability of channel occupancy conflicts. The relay node with a load rate of less than 60% is selected as the next hop based on the neighbor node load table. The neighbor node load table is updated in memory in the form of a sliding window with a window length of 10 seconds and an update frequency of 1 Hz, which is used to dynamically reflect the instantaneous interference caused by metal irrigation facilities in the farmland environment. When allocating time slots using the Time Division Multiple Access (TDMA) mechanism, the TDMA mechanism must ensure that the time slot allocation satisfies the following conditions: video I-frame > valve state > video P-frame > video B-frame.

5. The decoder based on a self-organizing network for farmland video surveillance according to claim 4, characterized in that, The video acquisition module's acquisition steps are as follows: The Sony IMX415 sensor captures raw video at a resolution of 1080P and a sampling rate of 25-30fps. The first core in the dual-core processor module controls the H.265 compressed bitrate at 1.2Mbps to ensure that the video slot utilization rate is ≤75% under the 2.5MHz channel, so that the original video is compressed to 45%±5% of its original size through H.265 encoding; Each video frame is also updated with a millisecond-level timestamp and GPS coordinates of the crop growth area.

6. The decoder based on a self-organizing network for farmland video surveillance according to claim 5, characterized in that, The execution steps of the RS485 interface module are as follows: The Modbus-RTU protocol bus connected to the valve controller is polled periodically every 500ms. When a level change in the valve status is detected, a hardware interrupt is immediately triggered. When a fault code is detected in the valve status, the second core immediately sends a forced preemption signal to the Wi-SUN communication module, interrupting the current video time slot and prioritizing the transmission of valve data. Extract the valve ID and status value, and append a common timestamp aligned with the interrupt trigger time.

7. The decoder based on a self-organizing network for farmland video surveillance according to claim 6, characterized in that, The steps for partitioning the storage module are as follows: The storage module's physical interface, QSPI, connects to the dual-core processor module; The storage area of ​​the storage module is divided into a circularly overwritten video buffer from 0x0000 to 0x7FFFFF; The storage area from 0x800000 to 0x81FFFF is divided into a non-volatile valve status information area; The storage area from 0x820000 to 0x83FFFF is divided into firmware and OTA backup areas.

8. The decoder based on a self-organizing network for farmland video surveillance according to claim 7, characterized in that, The spatiotemporal synchronization packet consists of a header, video data, valve data, and a trailer. The header includes a type identifier (0xFF) and a common timestamp. GPS coordinates of the seedling area, where the type identifier 0xFF triggers the receiver to perform spatiotemporal alignment processing; Video data includes I / P frames; Valve data includes the valve ID and the status value of the corresponding valve ID; The packet ends with a CRC32 verification block; The steps for generating a spacetime synchronization package are as follows: If a valve state change occurs within 50ms after the start of video frame acquisition, the valve data is considered to be the same spatiotemporal event as the corresponding frame video data; otherwise, the valve data is packaged independently and spatiotemporal binding is not performed.

9. A data transmission method based on a farmland video surveillance self-organizing network decoder, implemented by the farmland video surveillance self-organizing network decoder as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Data Acquisition Collaboration: After the video acquisition module acquires a 1080P image frame, the first core of the dual-core processor module performs H.265 encoding and writes the GPS coordinates and timestamp of the seedling area into the packet header. When the RS485 interface module polls for a change in valve status, the second core of the dual-core processor module encapsulates the valve ID, status value and timestamp into an emergency flag packet. S2, Spatiotemporal Synchronization Packet Generation: The second core appends the valve emergency flag packet to the header of the same video frame to form a spatiotemporal synchronization packet, and passes it to the Wi-SUN communication module through a circular buffer in shared memory; S3, Wi-SUN Adaptive Transmission: The Wi-SUN communication module detects the received signal strength indicator RSSI in real time. When RSSI < -85dBm, it switches to the 2.5MHz wide channel and selects a relay node with a load rate of less than 60% as the next hop by querying the neighbor node load table. S4. Receiver Synchronization Verification: The receiver performs pixel-level spatiotemporal alignment based on the timestamp in the packet header and the timestamp of the emergency flag packet, and overlays the valve status icon on the video playback display interface. When the CRC32 verification fails, the receiver returns a NACK code to request the sender to retransmit the last N packets, and N is configured by the user between 2 and 5.

10. The data transmission method based on the self-organizing network decoder for farmland video surveillance according to claim 8, characterized in that, In step S4, when the receiving end overlays the valve status icon on the video playback display interface, it can... The difference between the timestamp of the first core and the current system time Provide color-coded prompts: when When green is displayed; when When it is yellow, it will be displayed. when When this occurs, a red indicator will be displayed and a local alarm will be triggered.

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