Short-wave broadcast message transmission method, device, equipment and medium

Abstract

A short-wave broadcast message transmission method, apparatus and device, and a medium, the method comprising: generating an embedded audio based on an original audio, using a PN sequence as an original watermark signal; supplementing the original audio and obtaining an audio feature signal through a feature extraction model; a watermark signal with a specific bandwidth is obtained based on the PN sequence, shaping is carried out by using an audio characteristic signal, and a message escape result is mapped to the shaped PN sequence to form an embedded watermark; the audio processor is used for synthesizing an audio with a watermark based on the embedded audio and the embedded watermark and outputting the audio with the watermark to the transmitting end; an audio frequency band containing a watermark is obtained based on the audio of a receiving end, correlation operation is carried out on each frame of the audio frequency band and a PN sequence, correlation judgment is carried out through correlation peak values and positions, and if continuous three frames meet correlation judgment conditions, it is considered that one byte is successfully de-embedded; and judging whether the adjacent result and the previous result are the same group of data according to the correlation peak position. According to the invention, the arrival rate of the transmission message in the short-wave broadcast is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of shortwave communication, and in particular to a shortwave broadcast message transmission method, device, equipment and medium. Background Art

[0002] As a radio transmission technology, shortwave communication has the characteristics of strong penetration, good anti-interference ability, no restrictions on network hubs and active repeater systems, and low operating costs. In various scenarios such as military, emergency response, and disaster relief, its unique advantages and wide applicability make shortwave broadcast message transmission a preferred method, and even a strategic backup communication method.

[0003] When transmitting messages in shortwave broadcasting, since the shortwave broadcasting transmission system has strict requirements on transmission indicators, including amplitude-frequency characteristics, signal-to-noise ratio, harmonic distortion, etc., when the message is embedded at the transmitter, it is easy to be mismatched with the working frequency band, transmission power and modulation method of the existing transmission system, affecting its various transmission indicators. At the same time, the shortwave channel transmission environment is harsh, and the signal is easily affected by ionospheric changes, resulting in serious signal attenuation, multipath effects and interference. In long-distance transmission, the same area may be covered by shortwave signals from different sources, which increases the difficulty of message identification and analysis. These factors have a negative impact on the arrival rate of messages. Summary of the invention

[0004] The present invention provides a shortwave broadcast message transmission method, device, equipment and medium, which solves the problem of how to improve the arrival rate of messages transmitted in shortwave broadcasting.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, a shortwave broadcast message transmission method is provided, comprising:

[0007] Based on the original audio of the input program of the shortwave broadcast transmitter, an embedded audio for synthesizing the watermarked audio is generated through a band-stop filter with a set bandwidth, wherein a PN sequence is used as the original watermark signal;

[0008] The original audio is divided into frames and the frame length is adjusted to make the frame front and back padded, and an audio feature signal for shaping the watermark signal is obtained based on the PN sequence and the padded original audio through a feature extraction model;

[0009] Based on the PN sequence, a watermark signal of a specific bandwidth is obtained by a bandpass filter with a set bandwidth, the watermark signal of the specific bandwidth is shaped by using the audio characteristic signal, and the message escape result is mapped to the shaped PN sequence to form an embedded watermark;

[0010] synthesizing watermarked audio based on the embedded audio and the embedded watermark, and outputting the synthesized audio to an audio processor of the shortwave broadcast transmitter;

[0011] For the audio received by the shortwave broadcast receiving end, the audio frequency band containing the embedded watermark is obtained through a filter, each frame is subjected to FFT processing and correlation operation is performed with the PN sequence processed by FFT, and after IFFT processing, correlation judgment is made through correlation peak value and position, and if three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded;

[0012] After a byte is successfully de-embedded, the byte adjacent to it is called an adjacent result. Whether the adjacent result is the same group of data as the previous result is determined based on its correlation peak position. If the distance between the correlation peak position of the adjacent result and the correlation peak position of the previous byte is less than a threshold, it is determined that they are the same group of data; otherwise, it is determined that they belong to two groups of data.

[0013] In a first possible implementation manner of the first aspect, synchronization data is added in front of the message escape result, wherein each byte of the synchronization data and the message escape result is configured as triple redundancy.

[0014] In a second possible implementation of the first aspect, the blocking bandwidth of the band-stop filter is 0 Hz to 3 kHz; the passing bandwidth of the bandpass filter is 3 kHz to 5 kHz; and the embedded watermark is embedded between the 3 kHz to 5 kHz frequency band of the watermarked audio.

[0015] In a third possible implementation manner of the first aspect, obtaining the audio feature signal for shaping the watermark signal based on the PN sequence and the padded original audio by using a feature extraction model specifically includes:

[0016] Using 32 sub-band analysis filters to obtain the PN sequence and the sub-band signal vector sets X and Y of the padded original audio respectively;

[0017] X={X1,X2,…,X 32}; Y = {Y1, Y2, ..., Y 32};

[0018] The ratio calculated by using the padded original audio and the subband signal of the PN sequence is the audio feature signal; the audio feature signal is a vector set Z:

[0019] Z={Z1,Z2,…,Z 32}

[0020] Z k =|X k | / (Y k 2+eps) 0.5 , k=1,2,…,32

[0021] Among them, Z k is the kth ratio signal of the audio feature signal, X k is the kth sub-band signal of the completed original audio sub-band signal vector set X, Y k It is the kth subband signal of the subband signal vector set Y of the PN sequence.

[0022] Based on the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the sub-band signal vector set W embedded with the watermark is calculated by the following formula:

[0023] W k =Y k ·Z k ,k=1,2,…,32

[0024] Among them, W k is the subband signal of the subband signal vector set W embedded with the watermark, W = {W1, W2, …, W 32}, Z k is the kth ratio signal of the audio feature signal, Y k It is the kth subband signal of the subband signal vector set Y of the PN sequence.

[0025] In a fifth possible implementation manner of the first aspect, the correlation judgment is made by using the correlation peak value and the position, and if three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded, specifically including:

[0026] Get the correlation peak and position of the current frame.

[0027] Determine whether the peak value is less than the threshold. If the relevant peak value is less than the set threshold, it is considered that the frame is not successfully de-embedded;

[0028] If the correlation peak value is greater than or equal to the threshold, the number of frames with continuous successful correlation is checked, and if the current frame is the first time that the correlation peak value is detected to be greater than the threshold, the number of frames with continuous successful correlation is set to 1;

[0029] If the current frame is not the first time that the correlation peak value is detected to be greater than the threshold, it is determined whether the distance between the correlation peak position of the current frame and the correlation peak position of the previous frame is greater than the threshold. If the distance is greater than the threshold, it is considered that the continuous correlation is successful, and the number of frames with the continuous correlation success is increased by 1;

[0030] If the distance is less than or equal to the threshold, it is determined whether the number of frames with continuous successful correlation reaches the threshold. If so, the continuous correlation is considered to have failed, and the number of frames with continuous successful correlation is set to 0; if not, the continuous correlation is considered to have succeeded, and the number of frames with continuous successful correlation is increased by 1.

[0031] In a second aspect, a shortwave broadcast message transmission device is provided, comprising:

[0032] An audio preprocessing module is used to generate embedded audio for synthesizing watermarked audio based on the original audio of the input program of the shortwave broadcast transmitter through a band-stop filter with a set bandwidth, wherein a PN sequence is used as the original watermark signal;

[0033] An audio feature signal extraction module, used for framing the original audio and adjusting the frame length to make the frame front and back padded, and obtaining an audio feature signal for shaping the watermark signal based on the PN sequence and the padded original audio through a feature extraction model;

[0034] A message watermark generation module is used to obtain a watermark signal of a specific bandwidth based on the PN sequence through a bandpass filter with a set bandwidth, shape the watermark signal of the specific bandwidth using the audio characteristic signal, and map the message escape result to the shaped PN sequence to form an embedded watermark;

[0035] A watermarked audio synthesis module, used for synthesizing the watermarked audio based on the embedded audio and the embedded watermark, and outputting the synthesized watermarked audio to the audio processor of the shortwave broadcast transmitter;

[0036] The single-frame de-embedding module is used to obtain the audio frequency band containing the embedded watermark through a filter for the audio received by the shortwave broadcast receiving end, perform FFT processing on each frame and perform correlation operation with the PN sequence processed by FFT, and make correlation judgment based on the correlation peak value and position after IFFT processing. If three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded;

[0037] The adjacent result judgment module is used to successfully de-embed a byte and call the adjacent de-embedded byte as an adjacent result. It is judged whether the adjacent result is the same group of data as the previous result based on its correlation peak position. If the distance between the adjacent result correlation peak position and the previous byte correlation peak position is less than a threshold, it is judged that they are the same group of data. Otherwise, it is judged that they belong to two groups of data.

[0038] In a first possible implementation manner of the second aspect, synchronization data is added in front of the message escape result, wherein each byte of the synchronization data and the message escape result is configured as triple redundancy.

[0039] In a third aspect, an electronic device is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of the shortwave broadcast message transmission method as described in the first aspect.

[0040] In a fourth aspect, a readable storage medium is provided, on which a program or instruction is stored. When the program or instruction is executed by a processor, the steps of the shortwave broadcast message transmission method as described in the first aspect are implemented.

[0041] The shortwave broadcast message transmission method of the present invention has the following advantages:

[0042] By embedding a watermark in the program content before the audio processor at the shortwave broadcast transmitting end, de-embedding the watermark on the demodulated program audio at the receiving end, and restoring the message from the de-embedded result for subsequent application, the watermark content is hidden in the audio program and cannot be detected by the human ear. After the fading interference of the shortwave ionosphere, the watermark can still be ensured to arrive at the receiving location with the program content. The message embedding and de-embedding scheme makes the message highly robust and can distinguish the message content from different sources. When watermarks from more than one source arrive at the same time, they can be detected separately, thereby achieving the effect of ensuring a high arrival rate of the message content without affecting the transmission indicators of the existing transmission system.

[0043] The device, electronic device and readable storage medium corresponding to the shortwave broadcast message transmission method of the present invention can achieve the same technical effects, and will not be described here to avoid repetition. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A schematic flow chart of a shortwave broadcast message transmission method provided in an embodiment of the present application;

[0045] Figure 2 A schematic diagram of a frame structure provided in an embodiment of the present application;

[0046] Figure 3 A schematic flow chart of a watermark embedding process provided in an embodiment of the present application;

[0047] Figure 4 A schematic diagram of a watermark embedding position frequency domain provided in an embodiment of the present application;

[0048] Figure 5 A schematic flow chart of a single-frame data de-embedding process provided in an embodiment of the present application;

[0049] Figure 6 A schematic flowchart of a correlation determination process provided in an embodiment of the present application;

[0050] Figure 7 A schematic diagram of a shortwave broadcast message transmission link provided in an embodiment of the present application;

[0051] Figure 8 A schematic diagram of the structure of a shortwave broadcast message transmission device provided in an embodiment of the present application;

[0052] Fig. 9 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0053] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose, the technical solutions in the embodiments of the present application are clearly described. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0054] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0055] The description of the method flow in the specification of the present application and the steps of the flowchart in the drawings of the present specification do not have to be strictly executed according to the step numbers, and the method steps can be executed in a different order. Moreover, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0056] The following is a detailed description of a shortwave broadcast message transmission method, device, equipment and medium provided in an embodiment of the present application in conjunction with the accompanying drawings and preferred embodiments.

[0057] First, an application scenario of a shortwave broadcast message transmission method in an embodiment of the present application is described in detail.

[0058] The application background of transmitting messages in shortwave mainly comes from the unique advantages of shortwave communication and its wide applicability.

[0059] First of all, shortwave communication is not restricted by geographical location and can achieve long-distance communication, especially in mountainous areas, deserts, oceans and other areas where ultra-short waves cannot reach. Shortwave communication has become the preferred means of long-distance communication.

[0060] Secondly, shortwave communication has strong autonomous communication capability and anti-destruction capability. Once a war or disaster occurs, various communication networks may be destroyed, while shortwave communication can maintain relatively stable communication capabilities. This makes shortwave communication also play an important role in crisis response and disaster relief.

[0061] In addition, shortwave communication also has the advantage of low operating costs. Compared with satellite communications, the shortwave communication system has mature sending and receiving equipment, very low operating and maintenance costs, and no need to pay phone bills. This is a more economical option for some institutions and organizations with limited budgets.

[0062] In the solution for transmitting messages in shortwave broadcasting:

[0063] 1) Does not affect the launch indicators of the existing launch system.

[0064] The shortwave broadcast transmission system has strict requirements on transmission indicators, including amplitude-frequency characteristics, signal-to-noise ratio, harmonic distortion, etc. Embedding messages at the transmitter needs to ensure that they match the operating frequency band, transmission power and modulation mode of the existing transmission system and cannot affect its various transmission indicators.

[0065] 2) Ensure the arrival rate of message content.

[0066] Shortwave channel transmission often faces severe signal attenuation, multipath effects and interference, and the transmission environment is extremely harsh. At the same time, due to the long propagation distance of shortwave, the same area may be covered by shortwave signals from different sources. The message embedding and de-embedding scheme needs to make the message highly robust and able to distinguish the message content from different sources to ensure the arrival rate of the message content.

[0067] Based on this, the embodiment of the present application provides a shortwave broadcast message transmission method based on a digital audio watermarking technology of a PN sequence and a feature extraction model. The method can covertly embed the message into the audio of the shortwave broadcast program in the form of a watermark without affecting the transmission index of the existing transmission system. By optimizing the message embedding algorithm and the de-embedding algorithm, the method can effectively resist the strong interference caused by the ionosphere to the shortwave broadcast program, and ensure the stability and reliability of the message during long-distance transmission.

[0068] See also Figure 1 , the embodiment of the present application provides a shortwave broadcast message transmission method, such as Figure 1 As shown, the recommended method of the embodiment of the present application includes:

[0069] Step S1, based on the original audio of the input program of the shortwave broadcast transmitter, an embedded audio for synthesizing watermarked audio is generated through a band-stop filter with a set bandwidth, wherein a PN sequence is used as the original watermark signal.

[0070] Step S2, dividing the original audio into frames and adjusting the frame length to make the frame front and back padded, and obtaining an audio feature signal for shaping the watermark signal based on the PN sequence and the padded original audio through a feature extraction model.

[0071] Step S3, based on the PN sequence, obtain a watermark signal of a specific bandwidth through a bandpass filter with a set bandwidth, use the audio characteristic signal to shape the watermark signal of the specific bandwidth, map the message escape result to the shaped PN sequence, and form an embedded watermark.

[0072] In some possible implementations, considering the timeliness of message transmission and the autocorrelation of PN sequences of different lengths, for audio with a sampling rate of 48kHz, 8192 samples are used as a frame, and synchronization data is added to the front of each group of message escape results, wherein the synchronization data and each byte are transmitted in triple redundancy. The frame structure design for splitting audio is as follows: Figure 2 The synchronization data is used to help the receiving end identify the start position of the frame.

[0073] Among them, message escape refers to converting the original text or digital content into a form suitable for transmission. The message content can be numbers, letters, Chinese characters and common symbols. The process of character encoding conversion and numerical mapping is completed through the simplified Chinese character encoding standard GBK, and the content is finally converted into a code from 0 to 9. GBK uses multiple bytes (usually double bytes) to represent a character. This encoding method can cover a large number of Chinese characters and other symbols. When the embodiment of the present application converts a piece of content using GBK encoding, each character will be converted into a corresponding GBK encoding value. These encoding values ​​usually exist in the form of byte sequences. For Chinese characters, each character usually occupies two bytes. These GBK-encoded characters are converted into codes from 0 to 9 through numerical mapping. The steps are as follows:

[0074] (1) Extract GBK encoding value: First, extract the encoding value of each character from the GBK-encoded byte sequence. For double-byte characters, this usually means combining two consecutive bytes into a 16-bit value.

[0075] (2) Numerical mapping: Then, the extracted GBK code value is numerically mapped to convert it into a number between 0 and 9. This process is achieved through modulo operation, that is, dividing the GBK code value by 10 and taking the remainder. In this way, no matter what the original GBK code value is, the final mapping result will be a number between 0 and 9.

[0076] (3) Processing multi-byte characters: Since GBK encoding is a multi-byte encoding, in order to ensure that the encoding value of each character can be correctly extracted and mapped, the content containing multi-byte characters needs to be processed byte by byte and combined into a complete character encoding value before mapping.

[0077] (4) Output result: Finally, the mapped numbers from 0 to 9 are arranged in the order of the characters in the original content, and the final message escape result is output.

[0078] Step S4, synthesizing watermarked audio based on the embedded audio and the embedded watermark, and outputting the synthesized watermarked audio to the audio processor of the shortwave broadcast transmitter.

[0079] See also Figure 3 In the above steps S1 to S4, the original audio is passed through a band-stop filter of a specific bandwidth to generate audio for synthesis with a watermark, and at the same time, the frame length is adjusted, front and back padding is performed, and the feature vector of the signal is obtained through the feature extraction model, which is used to shape the PN sequence. The shaped PN sequence is embedded in the audio after filtering by a specific filter to generate audio carrying a watermark. It is worth noting that the embedding position of the embodiment of the present application is at the shortwave broadcast transmitter, and the audio processor embeds the watermark in the program content before (see Figure 7 ).

[0080] Furthermore, the blocking bandwidth of the band-stop filter is 0 Hz to 3 kHz; the passing bandwidth of the band-pass filter is 3 kHz to 5 kHz; and the embedded watermark is embedded between the 3 kHz to 5 kHz frequency band of the watermarked audio.

[0081] See also Figure 4 In terms of the selection of watermark embedding position, firstly, the bandwidth of shortwave broadcast modulation audio is 5kHz. Secondly, the main energy of audio is concentrated within 3k, which will significantly affect the audio quality, and the audio itself will cause strong interference to the watermark. Therefore, the watermark is embedded between 3kHz and 5kHz, which will not be cut by shortwave broadcast modulation, nor will it be interfered by the high energy of the original audio.

[0082] In some possible implementations, obtaining an audio feature signal for shaping the watermark signal based on the PN sequence and the padded original audio by using a feature extraction model specifically includes:

[0083] Step S201, using 32 sub-band analysis filters to obtain a PN sequence and a set of sub-band signal vectors X and Y of the padded original audio;

[0084] X={X1,X2,…,X 32}; Y = {Y1, Y2, ..., Y 32};

[0085] Step S202: The ratio calculated by using the padded original audio and the subband signal of the PN sequence is the audio feature signal; the audio feature signal is a vector set Z:

[0086] Z={Z1,Z2,…,Z 32}

[0087] Z k =|X k | / (Y k 2 +eps) 0.5 , k=1,2,…,32

[0088] Among them, Z k is the kth ratio signal of the audio feature signal, X k is the kth sub-band signal of the completed original audio sub-band signal vector set X, Y k It is the kth subband signal of the subband signal vector set Y of the PN sequence.

[0089] Furthermore, the subband signal vector set W embedded with the watermark is calculated by the following formula:

[0090] W k =Y k ·Z k ,k=1,2,…,32

[0091] Among them, W k is the subband signal of the subband signal vector set W embedded with the watermark, W = {W1, W2, …, W 32}, Z k is the kth ratio signal of the audio feature signal, Y k is the kth subband signal of the PN sequence subband signal vector set Y. This formula indicates that the audio feature signal is multiplied element by element by the PN sequence subband signal to obtain a subband signal vector set embedded with a watermark.

[0092] Step S5, for the audio received by the shortwave broadcast receiving end, the audio frequency band containing the embedded watermark is obtained through a filter, each frame is subjected to FFT processing and correlation operation is performed with the PN sequence processed by FFT, and after IFFT processing, correlation judgment is made through the correlation peak value and position; if three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded.

[0093] This step S5 is single frame de-embedding, see Figure 5-6During the implementation, a specific filter is used to filter out the specified audio frequency band, i.e., audio data from 3kHz to 5kHz, for each frame of data to be processed. Then, a fast Fourier transform (FFT) is performed to convert the data from the time domain to the frequency domain, and a correlation operation is performed with the PN sequence after FFT. Then, the inverse fast Fourier transform (IFFT) is used to return to the time domain. Based on the correlation peak value and its position, it is determined whether a byte of content is successfully de-embedded. If three consecutive frames meet the conditions, the de-embedding is confirmed to be successful. Specifically, it includes:

[0094] Step S501, obtaining the correlation peak value and position of the current frame.

[0095] Step S502, determining whether the peak value is less than a threshold. If the correlation peak value is less than the set threshold, it is considered that the frame is not successfully de-embedded.

[0096] Step S503, if the correlation peak value is greater than or equal to the threshold, check the number of frames with continuous successful correlation. If the current frame is the first time that the correlation peak value is detected to be greater than the threshold (that is, the number of frames with continuous successful correlation is 0), set the number of frames with continuous successful correlation to 1.

[0097] Step S504, if the current frame is not the first time that the correlation peak value is detected to be greater than the threshold, it is determined whether the distance between the correlation peak position of the current frame and the correlation peak position of the previous frame is greater than the threshold. If the distance is greater than the threshold, it is considered that the continuous correlation is successful, and the number of frames with successful continuous correlation is increased by 1.

[0098] Step S505, if the distance is less than or equal to the threshold, determine whether the number of frames with continuous successful correlation reaches the threshold. If so, it is considered that the continuous correlation fails and the number of frames with continuous successful correlation is set to 0; if not, it is considered that the continuous correlation is successful and the number of frames with continuous successful correlation is increased by 1.

[0099] In specific implementation, the correlation judgment principle is based on the value of the correlation peak and its position. If three consecutive frames meet the conditions, it can be determined that a byte of content is de-embedded. The first frame meets the correlation peak exceeding the threshold, the second frame meets the correlation peak exceeding the threshold and the distance between the peak position and the peak position of the previous frame is less than the threshold. The judgment standard for the third frame is the same as the second frame. If three consecutive frames meet the conditions, it is determined that a byte of content is de-embedded.

[0100] Step S6, after a byte is successfully de-embedded, the bytes de-embedded adjacent to it are called adjacent results. The adjacent results are judged whether they are the same group of data as the previous results based on their correlation peak positions. If the distance between the correlation peak position of the adjacent result and the correlation peak position of the previous byte is less than a threshold, they are judged to be the same group of data. Otherwise, they are judged to belong to two groups of data.

[0101] The above steps S5 to S6 are the watermark de-embedding process. In the watermark de-embedding process, based on the autocorrelation characteristics of the PN sequence, a single-frame de-embedding algorithm and adjacent result determination are included. The single-frame de-embedding algorithm uses a PN sequence set to correlate each frame of data with a signal in a specific bandwidth range in the audio, and determines its correlation based on the correlation peak and position. The adjacent result determination method is used to determine the continuity of adjacent correlation success results.

[0102] Based on the above technical solution, the embodiments of the present application have the following effects and advantages:

[0103] The embodiment of the present application embeds a watermark in the program content before the audio processor at the shortwave broadcast transmitting end, de-embeds the watermark on the demodulated program audio at the receiving end, and restores the message from the de-embedded result for subsequent application, so as to hide the watermark content in the audio program and make it imperceptible to the human ear. The watermark can still be ensured to arrive at the receiving location with the program content after the fading interference of the shortwave ionosphere. The message embedding and de-embedding scheme makes the message highly robust and can distinguish the message content from different sources. When watermarks from more than one source arrive at the same time, they can be detected separately, thereby achieving the effect of ensuring a high arrival rate of the message content without affecting the transmission indicators of the existing transmission system.

[0104] See also Figure 8 , corresponding to the above-mentioned shortwave broadcast message transmission method embodiment, the embodiment of the present application provides a shortwave broadcast message transmission device, the device comprising:

[0105] The audio preprocessing module 1001 is used to generate embedded audio for synthesizing watermarked audio based on the original audio of the input program of the shortwave broadcast transmitter through a band-stop filter with a set bandwidth, wherein a PN sequence is used as the original watermark signal;

[0106] The audio feature signal extraction module 1002 is used to divide the original audio into frames and adjust the frame length to make the frame front and back padded, and obtain the audio feature signal for shaping the watermark signal based on the PN sequence and the padded original audio through the feature extraction model;

[0107] The message watermark generation module 1003 is used to obtain a watermark signal of a specific bandwidth based on the PN sequence through a bandpass filter with a set bandwidth, reshape the watermark signal of the specific bandwidth using the audio characteristic signal, and map the message escape result to the reshaped PN sequence to form an embedded watermark;

[0108] A watermarked audio synthesis module 1004, used to synthesize the watermarked audio based on the embedded audio and the embedded watermark, and output it to the audio processor of the shortwave broadcast transmitter;

[0109] The single frame de-embedding module 1005 is used to obtain the audio frequency band containing the embedded watermark through a filter for the audio received by the shortwave broadcast receiving end, perform FFT processing on each frame and perform correlation operation with the PN sequence processed by FFT, and make correlation judgment based on the correlation peak value and position after IFFT processing. If three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded;

[0110] The adjacent result determination module 1006 is used to call the bytes adjacent to the bytes successfully de-embedded as adjacent results, and judge whether the adjacent results are the same group of data as the previous results based on their correlation peak positions. If the distance between the correlation peak position of the adjacent result and the correlation peak position of the previous byte is less than a threshold, they are determined to be the same group of data; otherwise, they are determined to belong to two groups of data.

[0111] Furthermore, synchronization data is added in front of the message escape result, wherein each byte of the synchronization data and the message escape result is configured as triple redundancy.

[0112] The above-mentioned shortwave broadcast message transmission device implements the steps and various processes of the above-mentioned shortwave broadcast message transmission method embodiment and can achieve the same technical effect. To avoid repetition, they are not described here.

[0113] See also Fig. 9 Corresponding to the above-mentioned shortwave broadcast message transmission method embodiment, the embodiment of the present application provides an electronic device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the steps of the above-mentioned shortwave broadcast message transmission method embodiment and the various processes of the embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0114] The memory 1009 can be used to store software programs and various data. The memory 1009 may mainly include a first storage area for storing programs or instructions and a second storage area for storing data, wherein the first storage area may store an operating system, an application program or instructions required for at least one function (such as a sound playback function, an image playback function, etc.), etc. In addition, the memory 1009 may include a volatile memory or a non-volatile memory, or the memory 1009 may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), a static random access memory (SRAM), a dynamic random access memory (DRAM), a synchronous dynamic random access memory (SDRAM), a double data rate synchronous dynamic random access memory (DDRSDRAM), an enhanced synchronous dynamic random access memory (ESDRAM), a synchronous link dynamic random access memory (SLDRAM) and a direct memory bus random access memory (DRRAM). The memory 1009 in the embodiment of the present application includes but is not limited to these and any other suitable types of memory.

[0115] The processor 1010 may include one or more processing units; optionally, the processor 1010 integrates an application processor and a modem processor, wherein the application processor mainly processes operations related to an operating system, a user interface, and application programs, and the modem processor mainly processes wireless communication signals, such as a baseband processor. It is understandable that the modem processor may not be integrated into the processor 1010.

[0116] Corresponding to the above-mentioned shortwave broadcast message transmission method embodiment, the embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by the processor, the steps of the above-mentioned shortwave broadcast message transmission method embodiment and the various processes of the embodiment are implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0117] The processor is the processor in the electronic device described in the above embodiment of the present application. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk or an optical disk.

[0118] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0119] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, a disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0120] It can be understood that the embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific embodiments, which are merely illustrative and not restrictive, and those skilled in the art are aware that various changes or equivalent replacements can be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, those of ordinary skill in the art can modify these features and embodiments to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention under the inspiration or teaching of the present application. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application belong to the scope protected by the present invention.

Claims

1. A shortwave broadcast message transmission method, characterized in that: include: Based on the original audio of the input program of the shortwave broadcast transmitter, an embedded audio for synthesizing the watermarked audio is generated through a band-stop filter with a set bandwidth, wherein a PN sequence is used as the original watermark signal; The original audio is divided into frames and the frame length is adjusted to make the frame front and back padded, and an audio feature signal for shaping the watermark signal is obtained based on the PN sequence and the padded original audio through a feature extraction model; Based on the PN sequence, a watermark signal of a specific bandwidth is obtained by a bandpass filter with a set bandwidth, the watermark signal of the specific bandwidth is shaped by using the audio characteristic signal, and the message escape result is mapped to the shaped PN sequence to form an embedded watermark; synthesizing watermarked audio based on the embedded audio and the embedded watermark, and outputting the synthesized audio to an audio processor of the shortwave broadcast transmitter; For the audio received by the shortwave broadcast receiving end, the audio frequency band containing the embedded watermark is obtained through a filter, each frame is subjected to FFT processing and correlation operation is performed with the PN sequence processed by FFT, and after IFFT processing, correlation judgment is made through correlation peak value and position, and if three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded; After a byte is successfully de-embedded, the byte adjacent to it is called an adjacent result. Whether the adjacent result is the same group of data as the previous result is determined based on its correlation peak position. If the distance between the correlation peak position of the adjacent result and the correlation peak position of the previous byte is less than a threshold, it is determined that they are the same group of data; otherwise, it is determined that they belong to two groups of data.

2. The shortwave broadcast message transmission method according to claim 1, characterized in that: The message escape result is preceded by synchronization data, wherein each byte of the synchronization data and the message escape result is configured as triple redundancy.

3. The shortwave broadcast message transmission method according to claim 1, characterized in that: The blocking bandwidth of the band-stop filter is 0 Hz to 3 kHz; the passing bandwidth of the band-pass filter is 3 kHz to 5 kHz; and the embedded watermark is embedded between the 3 kHz to 5 kHz frequency band of the watermarked audio.

4. The shortwave broadcast message transmission method according to claim 1, characterized in that: The method of obtaining the audio feature signal for shaping the watermark signal based on the PN sequence and the padded original audio by the feature extraction model specifically includes: Using 32 sub-band analysis filters to obtain the PN sequence and the sub-band signal vector sets X and Y of the padded original audio respectively; X={X1,X2,…,X 32 };Y={Y1,Y2,…,Y 32 }; The ratio calculated by using the padded original audio and the subband signal of the PN sequence is the audio feature signal; the audio feature signal is a vector set Z: Z={Z1,Z2,…,Z 32 } From k =|X k | / (Y k 2 +eps) 0.5 ,k=1,2,…,32 Among them, Z k is the kth ratio signal of the audio feature signal, X k is the kth sub-band signal of the completed original audio sub-band signal vector set X, Y k It is the kth subband signal of the subband signal vector set Y of the PN sequence.

5. The shortwave broadcast message transmission method according to claim 4, characterized in that: The subband signal vector set W embedded with the watermark is calculated by the following formula: W k =Y k ·Z k ,k=1,2,…,32 Among them, W k is the sub-band signal of the sub-band signal vector set W embedded with the watermark, W = {W1, W2, …, W 32 }, Z k is the kth ratio signal of the audio feature signal, Y k It is the kth subband signal of the subband signal vector set Y of the PN sequence.

6. The shortwave broadcast message transmission method according to claim 1, characterized in that: The correlation judgment is made by using the correlation peak value and position. If three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded, which specifically includes: Get the correlation peak and position of the current frame. Determine whether the peak value is less than the threshold. If the relevant peak value is less than the set threshold, it is considered that the frame is not successfully de-embedded; If the correlation peak value is greater than or equal to the threshold, the number of frames with continuous successful correlation is checked, and if the current frame is the first time that the correlation peak value is detected to be greater than the threshold, the number of frames with continuous successful correlation is set to 1; If the current frame is not the first time that the correlation peak value is detected to be greater than the threshold, it is determined whether the distance between the correlation peak position of the current frame and the correlation peak position of the previous frame is greater than the threshold. If the distance is greater than the threshold, it is considered that the continuous correlation is successful, and the number of frames with the continuous correlation success is increased by 1; If the distance is less than or equal to the threshold, it is determined whether the number of frames with continuous successful correlation reaches the threshold. If so, the continuous correlation is considered to have failed, and the number of frames with continuous successful correlation is set to 0; if not, the continuous correlation is considered to have succeeded, and the number of frames with continuous successful correlation is increased by 1.

7. A shortwave broadcast message transmission device, characterized in that: include: An audio preprocessing module is used to generate embedded audio for synthesizing watermarked audio based on the original audio of the input program of the shortwave broadcast transmitter through a band-stop filter with a set bandwidth, wherein a PN sequence is used as the original watermark signal; An audio feature signal extraction module, used for framing the original audio and adjusting the frame length to make the frame front and back padded, and obtaining an audio feature signal for shaping the watermark signal based on the PN sequence and the padded original audio through a feature extraction model; A message watermark generation module is used to obtain a watermark signal of a specific bandwidth based on the PN sequence through a bandpass filter with a set bandwidth, shape the watermark signal of the specific bandwidth using the audio characteristic signal, and map the message escape result to the shaped PN sequence to form an embedded watermark; A watermarked audio synthesis module, used for synthesizing the watermarked audio based on the embedded audio and the embedded watermark, and outputting the watermarked audio to the audio processor of the shortwave broadcast transmitter; The single-frame de-embedding module is used to obtain the audio frequency band containing the embedded watermark through a filter for the audio received by the shortwave broadcast receiving end, perform FFT processing on each frame and perform correlation operation with the PN sequence processed by FFT, and make correlation judgment based on the correlation peak value and position after IFFT processing. If three consecutive frames meet the correlation judgment condition, it is considered that one byte is successfully de-embedded; The adjacent result judgment module is used to successfully de-embed a byte and call the adjacent de-embedded byte as an adjacent result. It is judged whether the adjacent result is the same group of data as the previous result based on its correlation peak position. If the distance between the adjacent result correlation peak position and the previous byte correlation peak position is less than a threshold, it is judged that they are the same group of data. Otherwise, it is judged that they belong to two groups of data.

8. The shortwave broadcast message transmission device according to claim 7, characterized in that: The message escape result is preceded by synchronization data, wherein each byte of the synchronization data and the message escape result is configured as triple redundancy.

9. An electronic device, characterized in that: The electronic device comprises: a memory, a processor and a computer program stored in the memory and executable on the processor. When the computer program is executed by the processor, the steps of the shortwave broadcast message transmission method as claimed in any one of claims 1 to 6 are implemented.

10. A readable storage medium, characterized in that: The readable storage medium stores a program or instruction, and when the program or instruction is executed by the processor, the steps of the shortwave broadcast message transmission method according to any one of claims 1 to 6 are implemented.

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