An acoustic data compression and transmission method and system for ocean buoys

Abstract

This invention provides a method and system for acoustic data compression and transmission for marine buoys, comprising the following steps: fusing floating-point data output from multiple channels into a single data stream; dividing all data in the single data stream into M frames of fixed length (N data points per frame), and performing data compression processing on each data point in each frame to compress the floating-point value of each data point into a three-digit integer code; encoding all data points in each frame to form a data packet, the single data stream forming M data packets, and transmitting the M data packets back to the ground station via satellite; this invention has the following advantages: by optimizing the data encoding and compression mechanism, this invention significantly reduces the data size while maintaining key acoustic characteristics, enabling the processed acoustic signal amplitude data to be reliably output under limited serial communication and low-bandwidth satellite channel conditions, thereby improving the availability and data transmission efficiency of the marine acoustic monitoring system.

Description

Technical Field

[0001] This invention relates to the field of marine acoustics technology, and in particular to a method and system for acoustic data compression and transmission for marine buoys. Background Technology

[0002] Sound travels with minimal propagation loss and long distances in water, making it one of the most important and reliable means of detection and communication in the marine environment. To continuously acquire acoustic information in open ocean or unmanned environments, buoys are widely used to carry various sonar systems for routine maritime acoustic observations due to their ease of deployment, independent power supply, and good resistance to wind and waves. With increasing monitoring demands, single-channel acoustic signal processing is increasingly limited in feature extraction; therefore, multi-channel processing structures are typically constructed to achieve richer acoustic feature extraction through parallel data processing.

[0003] However, in the context of ocean buoys, uplinks often rely on low-speed satellite communication, which has extremely limited channel bandwidth, making it difficult to directly transmit raw acoustic data. To adapt to the limited channel conditions, it is necessary to effectively compress and encode the multi-channel acoustic data collected at the buoy end, in order to complete the data uplink while preserving as much key feature information as possible, thus ensuring the feasibility of remote monitoring and data analysis. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method and system for acoustic data compression and transmission for marine buoys, in order to solve the problem that in the current marine buoy scenario, the uplink mostly relies on low-speed satellite communication, whose channel bandwidth is extremely limited, making it difficult to directly transmit the raw acoustic data.

[0005] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0006] An acoustic data compression and transmission method for marine buoys includes the following steps: receiving acoustic data collected by a transducer; dividing the data into multiple logical channels using an algorithm; and fusing the floating-point data output from the multiple channels into a single data stream according to the channel sampling frequency in ascending order; dividing all data in the single data stream into M frames of a fixed length of N data points per frame; and performing data compression processing on each data point in each frame to compress the floating-point value of each data point into a three-bit integer code; after encoding all data in each frame, there are W-bit integer codes, and K-bit packet header integer codes and K-bit packet count integer codes are added before each frame to form a data packet; since all data in the single data stream is divided into M frames, the single data stream forms M data packets, and the M data packets are transmitted back to the ground station via satellite, where N, M, W, and K are all > 0 and are all positive integers.

[0007] In one embodiment of the present invention, the step of performing data compression processing on each data in each frame to compress the floating-point value of each data into a three-digit integer code includes: performing a threshold judgment on the audio signal amplitude data of each data in each frame, outputting a corresponding value according to the threshold judgment result, and then judging the positive or negative sign of the audio signal amplitude data of each data in each frame; taking the first non-zero number in the audio signal amplitude data as the first bit code, the second non-zero number as the second bit code, and the decimal point shift number as the third bit code, wherein the first bit code, the second bit code, and the third bit code can be respectively denoted as... , and Based on the judgment result, if the amplitude data of the sound signal is <0, then Thus, the final encoding of the sound signal amplitude data is obtained, and the final encoding is: .

[0008] An acoustic data compression and transmission system for marine buoys includes a data acquisition subsystem, a data processing subsystem, and a data compression and transmission subsystem; wherein, the data acquisition subsystem is used to realize acoustic data acquisition function; the data processing subsystem is used to realize target acoustic event recognition and multi-channel data fusion function; and the data compression and transmission subsystem is used to realize sound data compression and transmission function adapted to low bandwidth links.

[0009] In one embodiment of the present invention, the data acquisition subsystem includes a transducer, a preamplifier, a filter, and an analog-to-digital converter; wherein the transducer is used to receive underwater acoustic signals and convert the acoustic signals into electrical signals; the preamplifier is used to amplify the electrical signals output by the transducer; the filter is used to filter out out-of-band noise; and the analog-to-digital converter is used to convert analog signals into digital signals.

[0010] In one embodiment of the present invention, the data processing subsystem includes a plurality of downsampling units and an envelope detector; wherein, the downsampling units are used to downsample the acquired data, and different downsampling units have different downsampling coefficients; the envelope detectors are used to perform envelope detection on the downsampled data.

[0011] In one embodiment of the present invention, the data compression and transmission subsystem includes a multi-channel data fusion unit and a fixed-length framing module. The data compression and transmission subsystem further includes a data compression module and a packetization module. The multi-channel data fusion unit is used to fuse data detected from each channel. The fixed-length framing module divides the audio data into frames according to the data frame length within the data packet. The data compression module is used to encode the floating-point audio data within the frame using three-bit integer encoding. The packetization module is used to add a packet header and packet count before the encoded data.

[0012] In one embodiment of the present invention, the data compression module includes a threshold discrimination unit, a sign discrimination unit, a significant digit extraction unit, a decimal point position encoding unit, and a combined encoding unit; wherein, the threshold discrimination unit is used to perform threshold judgment on the sound signal amplitude data to limit the maximum / minimum amplitude and zero value of the output signal; the sign discrimination unit is used to determine the positive or negative sign of the sound signal amplitude data; the significant digit extraction unit is used to extract the first and second digits of the three-digit integer encoding; the decimal point position encoding unit is used to encode the decimal point position; and the combined encoding unit is used to form the final three-digit integer encoding.

[0013] As described above, the acoustic data compression and transmission method and system for marine buoys of the present invention have the following beneficial effects: The present invention can realize real-time acquisition and preprocessing of acoustic signals. Through optimized data encoding and compression mechanisms, it significantly reduces the data size while maintaining key acoustic characteristics, enabling the processed sound signal amplitude data to be reliably output under limited serial communication and low-bandwidth satellite channel conditions, thereby improving the availability and data transmission efficiency of the marine acoustic monitoring system. Moreover, the present invention uses an integer encoding method to map continuous floating-point amplitudes to fixed-length short codes, significantly reducing the representation overhead of individual data. Furthermore, it introduces the concept of "dynamic precision," adaptively adjusting the expression of effective bits and orders of magnitude according to the amplitude size. While maintaining the signal change trend and relative precision, it retains only the most informative effective digits, thereby achieving "precision preservation on demand and compression on demand." This method avoids the precision waste caused by fixed quantization and takes into account the expression needs of different amplitude ranges, ensuring that acoustic data still has usability and engineering value under extremely low bandwidth conditions. Attached Figure Description

[0014] Figure 1 This is a flowchart of the acoustic data compression and transmission method for marine buoys according to the first embodiment of the present invention;

[0015] Figure 2 This is an overall schematic diagram of the acoustic data compression and transmission system for marine buoys according to the second embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram of the data compression module in the acoustic data compression and transmission system for marine buoys according to the second embodiment of the present invention. Detailed Implementation

[0017] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0018] The first embodiment of the present invention relates to a method for acoustic data compression and transmission for marine buoys, and also to a method for acoustic data compression and transmission for marine buoys oriented towards low-bandwidth links. The process is as follows: Figure 1 As shown, the details are as follows:

[0019] Step 101: Receive acoustic data collected by the transducer, divide and generate multiple logical channels through an algorithm, and merge the floating-point data output by the multiple channels into one data channel in order of increasing channel sampling frequency.

[0020] Specifically, the acoustic data collected by the transducer in this embodiment is floating-point data.

[0021] Step 102: Divide all the data in one channel into M frames according to a fixed length of N data per frame, and perform data compression processing on each data in each frame to compress the floating-point value of each data into a three-digit integer code.

[0022] Specifically, each data point in each frame is compressed to encode its floating-point value into a three-digit integer. The process includes: first, thresholding the audio signal amplitude data `num` for each data point in each frame; if `num` > 3.3, outputting 330; if `num` < 3.3, outputting 335; if |num| < 0.001, outputting 0. Here, ±3.3 represents the maximum / minimum amplitude output by the analog-to-digital converter (ADC), and different ADCs have different maximum / minimum amplitudes. In this embodiment, the ADC used has a maximum / minimum amplitude of ±3.3. Then, the sign of the audio signal amplitude data `num` for each data point in each frame is determined.

[0023] Then, the first non-zero number in the amplitude data num of the sound signal is used as the first bit for encoding. The second non-zero number is used as the second bit of the code. The number of decimal point shifts is used as the third bit of the encoding. Finally, based on the judgment result, if the sound signal amplitude data num < 0, then... Thus, the final encoding of the sound signal amplitude data num is obtained, and the final encoding is: .

[0024] Step 103: All data in each frame is encoded with W-bit integer code, and K-bit header integer code and K-bit packet count integer code are added before each frame to form a data packet.

[0025] Step 104: All data in one data stream is divided into M frames, and the data stream forms M data packets, which are then transmitted back to the ground station via satellite.

[0026] In practical applications, the steps of acoustic data compression and transmission methods are as follows:

[0027] Step 1: Fuse floating-point data from multiple channels into one stream according to the channel sampling frequency in ascending order. For example, 4 channels, each with 1280 data points, are fused into one stream of 5120 data points. Step 2: Divide all data into 80 frames of a fixed length of 64 data points per frame. Step 3: Compress each data point in each frame, converting the floating-point value of each data point into a three-digit integer code. See steps a) to e) for specific data compression steps. Step 4: Each frame, after encoding, has 192 (… The first step involves adding a 4-bit header integer code and a 4-bit packet count integer code to the beginning of the frame, totaling 200 bits as a packet. The second step involves dividing all 5120 data points into 80 frames to form 80 data packets, which are then transmitted back to the ground station via satellite.

[0028] If the sound signal amplitude data num is -0.0256, first perform step a): threshold judgment: num does not meet the threshold judgment conditions of being greater than 3.3 or less than -3.3, and |num|<0.001; then perform step b): judge num as negative; according to step c): the first non-zero number is 2, then , , This represents the number of decimal places the decimal point moves when the exponent value `num` becomes a single-digit number with an absolute value greater than 0 and less than 10. In this example, to change from -0.0256 to 2.56, the decimal point needs to be shifted two places to the right. According to step d): if num < 0, then The value is 7; in step e), the final encoding is: .

[0029] The second embodiment of the present invention relates to an acoustic data compression and transmission system for ocean buoys, and is also an acoustic data compression and transmission system for ocean buoys oriented towards low-bandwidth links. Please refer to [link to relevant documentation]. Figure 2 and Figure 3 It includes a data acquisition subsystem, a data processing subsystem, and a data compression and transmission subsystem.

[0030] The data acquisition subsystem is used to realize the acoustic data acquisition function. The data acquisition subsystem includes a transducer, a preamplifier, a filter, and an analog-to-digital converter. The transducer is used to receive underwater acoustic signals and convert the acoustic signals into electrical signals; the preamplifier is used to amplify the electrical signals output by the transducer; the filter is used to filter out out-of-band noise; and the analog-to-digital converter is used to convert analog signals into digital signals.

[0031] The data processing subsystem is used to realize target acoustic event recognition and multi-channel data fusion functions. The data processing subsystem includes several downsampling units and envelope detectors. The downsampling units are used to downsample the acquired data, and different downsampling units have different downsampling coefficients. The envelope detectors are used to perform envelope detection on the downsampled data.

[0032] The data compression and transmission subsystem is used to implement audio data compression and transmission functions adapted to low-bandwidth links. The subsystem includes a multi-channel data fusion unit, a fixed-length framing module, a data compression module, and a packetization module. The multi-channel data fusion unit fuses the data detected from each channel; the fixed-length framing module frames the audio data according to the data frame length within the data packet; the data compression module encodes the floating-point audio data within the frame using three-bit integer encoding; and the packetization module adds a packet header and packet count before the encoded data.

[0033] The data compression module includes a threshold discrimination unit, a sign discrimination unit, a significant digit extraction unit, a decimal point position encoding unit, and a combined encoding unit. The threshold discrimination unit performs threshold judgment on the sound signal amplitude data, limiting the maximum / minimum amplitude and zero value of the output signal. The sign discrimination unit determines the positive or negative sign of the sound signal amplitude data. The significant digit extraction unit extracts the first and second digits of the three-digit integer encoding. The decimal point position encoding unit encodes the decimal point position. The combined encoding unit forms the final three-digit integer encoding. It should be noted that each unit in this data compression module processes the sound signal numerical data filtered by the envelope detector sequentially, mapping continuous floating-point amplitudes to fixed-length integer codes. While maintaining the amplitude variation trend and relative size relationship of the data, this significantly reduces the representation length of a single sample.

[0034] It is not difficult to see that this embodiment is a system implementation corresponding to the first embodiment, and this embodiment can be implemented in conjunction with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the first embodiment.

[0035] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0036] In summary, in restricted communication scenarios such as offshore buoys, direct transmission of floating-point numbers suffers from large data volume and high representation redundancy. The same amplitude value often requires multiple bytes to be fully expressed, which not only occupies valuable link bandwidth but also increases transmission latency and energy consumption. In contrast, this invention uses an integer encoding method to map continuous floating-point amplitude values ​​to fixed-length short codes, significantly reducing the representation overhead of individual data. Furthermore, it introduces the concept of "dynamic precision," adaptively adjusting the expression method of effective bits and orders of magnitude according to the amplitude size. While maintaining the signal change trend and relative accuracy, it retains only the most informative effective digits, thereby achieving "precision preservation on demand and compression on demand." This method avoids the precision waste caused by fixed quantization and takes into account the expression needs of different amplitude ranges, ensuring that acoustic data still has usability and engineering value under extremely low bandwidth conditions.

[0037] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. All equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A method for acoustic data compression and transmission for marine buoys, characterized in that, Includes the following steps: The system receives acoustic data collected by the transducer, divides it into multiple logical channels using an algorithm, and merges the floating-point data output from the multiple channels into one data stream according to the channel sampling frequency in ascending order. All data in the aforementioned data stream is divided into M frames of a fixed length of N data points per frame, and each data point in each frame is compressed to compress the floating-point value of each data point into a three-digit integer code. All data in each frame is encoded with W-bit integer codes, and K-bit header integer codes and K-bit packet count integer codes are added before each frame to form a data packet; All data in the data stream is divided into M frames, and the data stream forms M data packets. The M data packets are then transmitted back to the ground station via satellite, where N, M, W, and K are all > 0 and are all positive integers. The step of performing data compression processing on each piece of data in each frame, thereby compressing the floating-point value of each piece of data into a three-digit integer code, includes: The system performs threshold judgment on the audio signal amplitude data of each data in each frame, outputs the corresponding value based on the threshold judgment result, and then determines the positive or negative sign of the audio signal amplitude data of each data in each frame. The first non-zero number in the sound signal amplitude data is used as the first bit code, the second non-zero number as the second bit code, and the decimal point shift number as the third bit code. The first, second, and third bit codes can be denoted as follows: , and ; Based on the judgment result, if the amplitude data of the sound signal is <0, then Thus, the final encoding of the sound signal amplitude data is obtained, and the final encoding is: .

2. An acoustic data compression and transmission system for marine buoys, the system being used to implement the acoustic data compression and transmission method for marine buoys as described in claim 1, characterized in that: It includes a data acquisition subsystem, a data processing subsystem, and a data compression and transmission subsystem; The data acquisition subsystem is used to realize acoustic data acquisition; the data processing subsystem is used to realize target acoustic event recognition and multi-channel data fusion; and the data compression and transmission subsystem is used to realize sound data compression and transmission adapted to low-bandwidth links.

3. The acoustic data compression and transmission system for marine buoys according to claim 2, characterized in that: The data acquisition subsystem includes a transducer, a preamplifier, a filter, and an analog-to-digital converter; The transducer is used to receive underwater acoustic signals and convert the acoustic signals into electrical signals; the preamplifier is used to amplify the electrical signals output by the transducer; the filter is used to filter out out-of-band noise; and the analog-to-digital converter is used to convert analog signals into digital signals.

4. The acoustic data compression and transmission system for marine buoys according to claim 2, characterized in that: The data processing subsystem includes several down-conversion units and envelope detectors; The downsampling unit is used to downsample the acquired data, and different downsampling units have different downsampling coefficients; the envelope detector is used to perform envelope detection on the downsampled data.

5. The acoustic data compression and transmission system for marine buoys according to claim 2, characterized in that: The data compression and transmission subsystem includes a multi-channel data fusion unit and a fixed-length framing module. The data compression and transmission subsystem also includes a data compression module and a packetization module. The multi-channel data fusion unit is used to fuse the data detected from each channel; the fixed-length framing module divides the audio data into frames according to the length of the data frame within the data packet; the data compression module is used to encode the floating-point audio data within the frame using three-digit integers; and the packetization module is used to add a packet header and packet count before the encoded data.

6. The acoustic data compression and transmission system for marine buoys according to claim 5, characterized in that: The data compression module includes a threshold discrimination unit, a sign discrimination unit, a significant digit extraction unit, a decimal point position encoding unit, and a combined encoding unit; The threshold discrimination unit is used to perform threshold judgment on the amplitude data of the sound signal to limit the maximum / minimum amplitude and zero value of the output signal; the sign discrimination unit is used to determine the positive or negative sign of the amplitude data of the sound signal; the significant digit extraction unit is used to extract the first and second digits of the three-digit integer code; the decimal point position encoding unit is used to encode the decimal point position; and the combination encoding unit is used to form the final three-digit integer code.

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