Electromagnetic signal monitoring methods, devices, equipment and storage media

Abstract

This application provides an electromagnetic signal monitoring method, apparatus, device, and storage medium. The method includes: analyzing electromagnetic signals within a space to determine if an electromagnetic leakage signal exists; if an electromagnetic leakage signal is present, reconstructing the electromagnetic signal to obtain an image; extracting information from the image to obtain textual information; comparing the textual information according to a preset risk strategy to determine risk information and outputting alarm information. This application can promptly reconstruct electromagnetic signals after detecting a leakage signal, allowing users to immediately understand the content of the electromagnetic signal. It also provides timely alarms to users when a risk is detected due to an electromagnetic leakage signal, thereby improving the interaction between electromagnetic signal detection and the user. Furthermore, it visualizes the detection results in text form, improving the efficiency of electromagnetic signal detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computer security protection, in particular to an electromagnetic signal monitoring method and device, equipment and storage medium. BACKGROUND

[0002] Electronic equipment will produce electromagnetic radiation in the running of non-subjective communication, and the electromagnetic signal may contain useful information related to the equipment, causing the leakage of useful information, for example, the electromagnetic leakage of the video cable interface of the display device may contain video information. Therefore, the leakage detection of the electromagnetic signal has become the focus of people's research.

[0003] At present, the main detection method for electromagnetic leakage is manual detection using a detector, but this detection method can only detect the signal and cannot make the detection personnel know the content of the leaked signal, so the detection efficiency is low.

[0004] Therefore, how to improve the detection efficiency of the electromagnetic leakage signal has become a problem to be solved. SUMMARY

[0005] The present application aims at the deficiencies in the prior art, and provides an electromagnetic signal monitoring method, device, equipment and storage medium to solve the problem of low detection efficiency of electromagnetic leakage signals in the prior art.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides an electromagnetic signal monitoring method, which comprises:

[0008] Performing time-frequency domain conversion on the electromagnetic signal in the target space to obtain a frequency domain signal of the electromagnetic signal, performing feature extraction on the frequency domain signal to obtain a wave peak interval and a plurality of wave peak nodes of the frequency domain signal, and determining whether there is an electromagnetic leakage signal in the target space according to a preset signal threshold, the wave peak interval and the plurality of wave peak nodes of the frequency domain signal;

[0009] If yes, performing signal restoration on the electromagnetic signal to obtain an initial image of the electromagnetic signal, wherein the initial image includes text information corresponding to the electromagnetic signal;

[0010] Performing image correction on the initial image according to a synchronization signal extracted from the electromagnetic signal to obtain a corrected image;

[0011] Performing information extraction on the corrected image to obtain text information of the corrected image, and determining whether the text information of the corrected image belongs to risk information according to a preset risk strategy, and if yes, outputting alarm information corresponding to the text information of the corrected image.

[0012] Optionally, the feature extraction on the frequency domain signal to obtain the wave peak interval and the plurality of wave peak nodes of the frequency domain signal comprises:

[0013] performing second-order difference processing on the frequency domain signal to obtain a plurality of initial wave peak nodes corresponding to the frequency domain signal;

[0014] determining the wave peak interval and the plurality of wave peak nodes of the frequency domain signal according to the initial wave peak nodes.

[0015] Optionally, the determining the wave peak interval and the plurality of wave peak nodes of the frequency domain signal according to the initial wave peak nodes comprises:

[0016] performing screening on the plurality of initial wave peak nodes according to a first preset amplitude threshold and amplitudes of the initial wave peak nodes to obtain a plurality of optional wave peak nodes;

[0017] determining a plurality of wave peak node sets in turn by using a sliding window, and determining at least one optional wave peak node from each of the wave peak node sets in turn as the wave peak node, wherein the wave peak node set comprises a plurality of optional wave peak nodes adjacent to each other in turn;

[0018] performing difference calculation on the plurality of wave peak nodes to obtain the wave peak interval of the wave peak node.

[0019] Optionally, the determining whether the electromagnetic leakage signal exists in the target space according to the preset signal threshold and the plurality of wave peak nodes comprises:

[0020] comparing amplitudes of the plurality of wave peak nodes with a second preset amplitude threshold;

[0021] determining whether the electromagnetic leakage signal exists in the target space according to a comparison result and a target leakage judgment strategy.

[0022] Optionally, the signal restoration on the electromagnetic signal to obtain an initial image of the electromagnetic signal comprises:

[0023] storing the electromagnetic signal as phase-amplitude data;

[0024] determining amplitude data of the electromagnetic signal according to a subset of the phase-amplitude data;

[0025] obtaining intermediate amplitude data according to the amplitude data;

[0026] performing rearrangement processing on the intermediate amplitude data according to resolution information to obtain the initial image of the electromagnetic signal.

[0027] Optionally, the image correction on the initial image according to the synchronization signal extracted from the electromagnetic signal comprises:

[0028] vertical correction on the initial image according to a field synchronization signal in the synchronization signal to obtain an intermediate correction image;

[0029] horizontal correction on the intermediate correction image according to a line synchronization signal in the synchronization signal to obtain the corrected image.

[0030] Optionally, the information extraction on the corrected image to obtain the text information of the corrected image, and the determination of whether the text information of the corrected image belongs to risk information according to a preset risk policy, if yes, output of the alarm information corresponding to the text information of the corrected image, comprises:

[0031] information extraction on the corrected image by using a text recognition algorithm to obtain the text information of the corrected image;

[0032] extraction of the to-be-matched text information from the text information of the corrected image;

[0033] matching of the to-be-matched text information with the preset risk policy based on a preset matching algorithm;

[0034] if the to-be-matched text information matches the risk policy, output of the alarm information corresponding to the text information of the corrected image.

[0035] In a second aspect, the present application provides an electromagnetic signal monitoring device, the device comprising:

[0036] a signal analysis module, configured to: perform time-frequency domain conversion on an electromagnetic signal in a target space to obtain a frequency domain signal of the electromagnetic signal, perform feature extraction on the frequency domain signal to obtain a wave peak interval and a plurality of wave peak nodes of the frequency domain signal, and determine whether there is an electromagnetic leakage signal in the target space according to a preset signal threshold, the wave peak interval and the plurality of wave peak nodes of the frequency domain signal;

[0037] a signal restoration module, configured to: if yes, perform signal restoration on the electromagnetic signal to obtain an initial image of the electromagnetic signal, wherein the initial image comprises text information corresponding to the electromagnetic signal;

[0038] an image correction module, configured to: perform image correction on the initial image according to a synchronization signal extracted from the electromagnetic signal to obtain a corrected image;

[0039] an image analysis module, configured to: perform information extraction on the corrected image to obtain text information of the corrected image, and determine whether the text information of the corrected image belongs to risk information according to a preset risk policy, and if so, output alarm information corresponding to the text information of the corrected image.

[0040] Optionally, the signal analysis module is specifically configured to:

[0041] perform second-order difference processing on the frequency domain signal to obtain a plurality of initial wave peak nodes corresponding to the frequency domain signal;

[0042] determine a wave peak interval of the frequency domain signal and a plurality of wave peak nodes according to the initial wave peak nodes.

[0043] Optionally, the signal analysis module is specifically configured to:

[0044] perform screening on the plurality of initial wave peak nodes according to a first preset amplitude threshold and amplitudes of the initial wave peak nodes to obtain a plurality of selectable wave peak nodes;

[0045] determine a plurality of wave peak node sets in turn by using a sliding window, and determine at least one selectable wave peak node from each of the wave peak node sets in turn as the wave peak node, wherein the wave peak node set includes a plurality of selectable wave peak nodes that are adjacent in turn;

[0046] perform difference calculation on the plurality of wave peak nodes to obtain a wave peak interval of the wave peak node.

[0047] Optionally, the signal analysis module is specifically configured to:

[0048] compare the amplitudes of the plurality of wave peak nodes with a second preset amplitude threshold;

[0049] determine whether there is an electromagnetic leakage signal in the target space according to a comparison result and a target leakage determination strategy.

[0050] Optionally, the signal restoration module is specifically configured to:

[0051] store the electromagnetic signal as phase-amplitude data;

[0052] determine amplitude data of the electromagnetic signal according to a subset of the phase-amplitude data;

[0053] obtain intermediate amplitude data according to the amplitude data;

[0054] perform rearrangement processing on the intermediate amplitude data according to resolution information to obtain an initial image of the electromagnetic signal.

[0055] Optionally, the image correction module is specifically configured to:

[0056] correcting the initial image according to a field synchronization signal in the synchronization signals to obtain an intermediate corrected image;

[0057] correcting the intermediate corrected image according to a line synchronization signal in the synchronization signals to obtain the corrected image.

[0058] Optionally, the image analysis module is specifically configured to:

[0059] extracting information from the corrected image by using a character recognition algorithm to obtain character information of the corrected image;

[0060] extracting to-be-matched character information from the character information of the corrected image;

[0061] matching the to-be-matched character information with the preset risk policy based on a preset matching algorithm;

[0062] if the to-be-matched character information matches the risk policy, outputting alarm information corresponding to the character information of the corrected image.

[0063] In a third aspect, the present application provides an electronic device, comprising a processor, a storage medium, and a bus, the storage medium stores machine readable instructions executable by the processor, when the electronic device is running, the processor and the storage medium communicate through the bus, and the processor executes the machine readable instructions to perform the steps of the above electromagnetic signal monitoring method.

[0064] In a fourth aspect, the present application provides a computer readable storage medium, the computer readable storage medium stores a computer program, when the computer program is run by a processor, the steps of the above electromagnetic signal monitoring method are executed.

[0065] The present application has the following beneficial effects: by analyzing the electromagnetic signals in the space, it is determined whether there is an electromagnetic leakage signal in the space, when there is an electromagnetic leakage signal, the electromagnetic signal is restored to obtain an image of the electromagnetic signal, information is extracted from the image to obtain character information of the image, and the character information is compared according to a preset risk policy to determine risk information and output alarm information. The electromagnetic signal monitoring of the present application can restore the electromagnetic signal in time after detecting the electromagnetic leakage signal, so that the user can know the content of the electromagnetic signal in time, and the user can be alarmed in time when the electromagnetic leakage signal has a risk, thereby improving the interaction effect of electromagnetic signal detection and the user, and visualizing the detection result of the electromagnetic signal in the form of text to improve the efficiency of electromagnetic signal detection. BRIEF DESCRIPTION OF DRAWINGS

[0066] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those of ordinary skill in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0067] Figure 1 A schematic diagram of an architecture of an electromagnetic signal monitoring system provided by an embodiment of the present application is shown.

[0068] Figure 2 A flowchart of an electromagnetic signal monitoring method provided by an embodiment of the present application is shown.

[0069] Figure 3 A schematic diagram of a frequency domain signal provided by an embodiment of the present application is shown.

[0070] Figure 4 A flowchart of a self-correlation processing method provided by an embodiment of the present application is shown.

[0071] Figure 5 A flowchart of determining a wave peak node provided by an embodiment of the present application is shown.

[0072] Figure 6 A schematic diagram of screening a wave peak node provided by an embodiment of the present application is shown.

[0073] Figure 7 A flowchart of determining a selectable wave peak node provided by an embodiment of the present application is shown.

[0074] Figure 8 A schematic diagram of a sliding window filtering provided by an embodiment of the present application is shown.

[0075] Figure 9 A flowchart of determining whether there is an electromagnetic leakage signal provided by an embodiment of the present application is shown.

[0076] Figure 10 A flowchart of determining an initial image provided by an embodiment of the present application is shown.

[0077] Figure 11 A schematic diagram of an electromagnetic signal display provided by an embodiment of the present application is shown.

[0078] Figure 12 A flowchart of determining a corrected image provided by an embodiment of the present application is shown.

[0079] Figure 13 A flowchart of image correction provided by an embodiment of the present application is shown.

[0080] Figure 14 A flowchart of determining alarm information is shown according to an embodiment of the present application;

[0081] Figure 15 A structural schematic diagram of an electromagnetic signal monitoring device is shown according to an embodiment of the present application;

[0082] Figure 16 A structural schematic diagram of an electronic device is shown according to an embodiment of the present application. DETAILED DESCRIPTION

[0083] To make the objectives, technical solutions, and superiorities of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application are only intended to illustrate and describe the present application, and are not intended to limit the scope of the present application. In addition, it should be understood that the drawings are not drawn according to the actual proportions. The flowcharts show the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can not be implemented in sequence, and the steps without logical context relationship can be reversed in sequence or implemented simultaneously. In addition, one or more other operations can be added to the flowcharts or removed from the flowcharts under the guidance of the content of the present application.

[0084] In addition, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0085] It should be noted that the term “comprising” will be used in the embodiments of the present application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0086] The current manual detection method for electromagnetic signals can only detect electromagnetic signals, but cannot restore the electromagnetic signals to images. Therefore, when the electromagnetic leakage signals contain useful information, how to know the corresponding content of the electromagnetic leakage signals and timely alarm for the useful information in the electromagnetic leakage signals becomes a problem to be solved.

[0087] To solve the above problems, the present application provides an electromagnetic signal monitoring method, which can be applied to an electromagnetic signal monitoring system, such as Figure 1As shown in FIG. 1, an architecture diagram of an electromagnetic signal monitoring system is given in the present application, referring to Figure 1 The electromagnetic signal monitoring system can include a signal collection layer, a signal analysis layer, a signal restoration layer, and an image analysis layer.

[0088] Referring to Figure 1 The signal collection layer can include at least one signal receiver, which can be arranged in the target space to be monitored to collect electromagnetic signals in the target space. The signal analysis layer can analyze and identify electromagnetic signals to identify electromagnetic leakage signals. The signal restoration layer can analyze and restore electromagnetic signals to obtain image information corresponding to the electromagnetic signals. The image analysis layer can further analyze the image information and make risk judgments and alarms on the image information in combination with risk strategies. The signal analysis layer, the signal restoration layer, and the image analysis layer can be deployed in an electronic device.

[0089] Next, referring to Figure 2 , the electromagnetic signal monitoring method of the present application is further described. The execution subject of the method can be the electronic device described above. As shown in Figure 2 , the method includes:

[0090] S201: performing time-frequency domain conversion on electromagnetic signals in a target space to obtain frequency domain signals of the electromagnetic signals, performing feature extraction on the frequency domain signals to obtain a wave peak interval and a plurality of wave peak nodes of the frequency domain signals, and determining whether there is an electromagnetic leakage signal in the target space according to a preset signal threshold, the wave peak interval, and the plurality of wave peak nodes.

[0091] Optionally, a plurality of signal receivers in the space can be used to collect electromagnetic signals in a certain segment range in the space, and the signal analysis layer described above can be used to convert the electromagnetic signals from time domain signals to frequency domain signals.

[0092] It is worth noting that in order to identify the video leakage signal, the electromagnetic characteristics of the leakage signal need to be known. Because the electromagnetic detection device will receive many electromagnetic signals unrelated to the leakage signal, the electromagnetic characteristics can be used to quickly identify whether the video leakage signal exists, so the electromagnetic signals after time-frequency domain conversion can be subjected to feature extraction.

[0093] Optionally, the characteristics of the electromagnetic signal can include the amplitude and frequency of the electromagnetic signal, and each wave peak node can correspond to an amplitude and frequency value.

[0094] For example, as shown in Figure 3 , the horizontal axis represents the frequency and the vertical axis represents the amplitude. In the figure, points A and B are both wave peak nodes, and the distance between the horizontal coordinates of points A and B is the wave peak interval.

[0095] Optionally, since the electromagnetic characteristics of the electromagnetic leakage signal have particularity, the amplitude and the peak interval will be different, and thus whether the electromagnetic leakage signal exists in the target space can be determined according to the preset signal threshold, the peak interval of the frequency domain signal, and the plurality of peak nodes.

[0096] For example, the preset signal threshold can be a signal threshold preset according to the electromagnetic characteristics of the electromagnetic leakage signal, such as a signal threshold set by a manager according to an experience value or an electromagnetic protection standard.

[0097] S202: If yes, the electromagnetic signal is subjected to signal restoration to obtain an initial image of the electromagnetic signal, and the initial image includes the text information corresponding to the electromagnetic signal.

[0098] Optionally, if the electromagnetic leakage signal exists in the target space, the original electromagnetic signal can be subjected to signal restoration by the signal restoration layer.

[0099] Optionally, the signal restoration layer can first restore the electromagnetic signal to obtain an amplitude sequence corresponding to the electromagnetic signal, and then combine the amplitude sequence with the resolution information of the display to obtain the initial image corresponding to the electromagnetic signal.

[0100] Optionally, taking the monitoring of the video electromagnetic leakage signal as an example, when the electromagnetic signal is a video leakage signal, the text information corresponding to the electromagnetic signal can be the text information in the video picture.

[0101] It should be noted that in different electromagnetic signal monitoring scenarios, the text information of the electromagnetic signal can be the text information corresponding to the signal source, for example, when an electromagnetic leakage signal is generated during the transmission of a picture, the text information can be the text information contained in the picture.

[0102] S203: The initial image is subjected to image correction according to the synchronization signal extracted from the electromagnetic signal to obtain a corrected image.

[0103] Optionally, the synchronization signal can be obtained by subjecting the electromagnetic signal to autocorrelation processing, and the synchronization signal can include a line synchronization signal and a field synchronization signal.

[0104] For example, the autocorrelation processing process can be as shown in Figure 4 , with reference to Figure 4 , wherein v(t) is a video signal, n(t) is a noise signal, s(t) is a received video radiation signal (i.e., an electromagnetic signal), and the video radiation signal is modulated with its own delayed signal to obtain a synchronization signal Rss(t) thereof. The calculation of the synchronization signal Rss(t) can be as shown in the following formula (1):

[0105]

[0106] Wherein, s(t+r) represents a delayed signal of the video radiation signal.

[0107] It should be noted that the resolution of the display can also be calculated according to the synchronization signal. Those skilled in the art know that the line synchronization signal and the field synchronization signal can be determined by the wave crest of the synchronization signal. The line synchronization signal can determine the effective line signal interval on the display, and the field synchronization signal can determine the effective field signal interval on the display, and then the effective video signal interval of the display is determined, so that the resolution of the display is calculated. The specific process is not described here.

[0108] On the basis of obtaining the above-mentioned synchronization signal, the initial image can be image-corrected by the aforementioned image analysis layer to obtain a corrected image.

[0109] S204: Information extraction is performed on the corrected image to obtain text information of the corrected image, and it is determined according to a preset risk policy whether the text information of the corrected image belongs to risk information. If yes, the alarm information corresponding to the text information of the corrected image is output.

[0110] Optionally, the text information of the corrected image can be text information corresponding to the electromagnetic signal.

[0111] Optionally, the preset risk policy can be a preset risk word set. The image analysis layer extracts text information from the corrected image, and compares the text information with the risk word set. If the extracted text information of the corrected image is successfully compared with the risk word set, it can be determined that the text information is risk information, and the alarm information corresponding to the text information of the corrected image is output.

[0112] Optionally, the alarm information can inform the user that there is an electromagnetic leakage, and the electromagnetic leakage signal contains risk information.

[0113] In the embodiments of the present application, by analyzing the electromagnetic signal in the space, it is determined whether there is an electromagnetic leakage signal in the space. When there is an electromagnetic leakage signal, the electromagnetic signal is restored to obtain an image of the electromagnetic signal. Information extraction is performed on the image to obtain text information of the image. The text information is compared according to a preset risk policy to determine risk information and output alarm information. The electromagnetic signal monitoring of the present application can restore the electromagnetic signal in time after detecting the electromagnetic leakage signal, so that the user can know the content of the electromagnetic signal in time, and the user can be alarmed in time when the content of the electromagnetic leakage signal contains risk based on the preset risk policy, thereby improving the interaction effect of electromagnetic signal detection and the user, and visualizing the detection result of the electromagnetic signal in the form of text to improve the efficiency of electromagnetic signal detection.

[0114] The following describes the steps for extracting features from a frequency domain signal to obtain the peak spacing and multiple peak nodes. Figure 5 As shown, the above step S201 includes:

[0115] S501: Perform second-order difference processing on the frequency domain signal to obtain multiple initial peak nodes corresponding to the frequency domain signal.

[0116] Optionally, the aforementioned signal analysis layer can perform second-order difference processing on the frequency domain signal to determine the peaks and troughs in the frequency domain signal. The number of initial peak nodes can be multiple.

[0117] For example, the process of performing second-order difference processing on a frequency domain signal can be as follows.

[0118] Assume the frequency domain array corresponding to the frequency domain signal is F = [f1, f2, f3, f4, ..., f n Find the difference between them: Diff = f i+1 -f i The differenced data is normalized according to the following formula (2):

[0119]

[0120] The normalized results above are then further processed as follows:

[0121] -1if f(i)=0&f(i-1)<0;

[0122] 1 if f(i) = 0 & f(i-1) > 0;

[0123] Perform another difference calculation on the data processed above: Diff = f i+1 -f i -2 / +2 represents the peak / trough.

[0124] S502: Determine the peak spacing and multiple peak nodes of the frequency domain signal based on the initial peak nodes.

[0125] Optionally, based on the initial peak node, the peak spacing and multiple peak nodes of the frequency domain signal can be determined, wherein the peak spacing can characterize the horizontal coordinate distance between two adjacent peak nodes.

[0126] For example, Figure 6 The amplitude-frequency diagram of a frequency domain signal obtained after second-order differential processing is shown. The points marked in the diagram are the initial peak nodes of the frequency domain signal after second-order differential processing.

[0127] The following explains the steps for determining the peak spacing and multiple peak nodes of the frequency domain signal based on the initial peak node. Figure 7As shown, the above step S502 includes:

[0128] S701: Based on the first preset amplitude threshold and the amplitude of each initial peak node, multiple initial peak nodes are filtered to obtain multiple selectable peak nodes.

[0129] Optionally, the first preset amplitude threshold can be a threshold set based on the amplitude of previous electromagnetic leakage signals, for example, refer to Figure 6 Peak nodes whose vertical axis exceeds the range of the dashed line can be considered as optional peak nodes that exceed the first preset amplitude threshold.

[0130] S702: A sliding window is used to determine multiple sets of peak nodes in sequence, and at least one optional peak node is determined from each set of peak nodes as a peak node in sequence, wherein the set of peak nodes includes multiple optional peak nodes that are adjacent to each other in sequence.

[0131] Optionally, a sliding window can be used to filter peak nodes that exceed the first preset amplitude threshold, which can filter out situations where multiple small peaks may exist on the same peak.

[0132] Optionally, a sliding window can be used, moving one step at a time. Each time the window moves, the number of peak nodes within the window range can be calculated. If the number of nodes is greater than one, only the peak node corresponding to the maximum value can be kept, and the other peak nodes can be removed.

[0133] For example, the interval between the signal peaks of the electromagnetic leakage signal is assumed to be between 30kHz and 40kHz, and the width of the sliding window can be in the range of 10kHz to 20kHz, so as to ensure that each sliding only processes one peak node and its adjacent small spikes.

[0134] Reference Figure 8 The sliding window 801 contains two selectable peak nodes, A and C. If the amplitude of point A is greater than that of point C, then point A can be selected as the peak node. Figure 8 The final set of peak nodes can include {A, B, D}.

[0135] S703: Perform differential calculations on multiple peak nodes to obtain the peak interval of the peak nodes.

[0136] Optionally, the adjacent abscissas of the filtered peak nodes can be differentially calculated. If the distances are the same within the allowable error range, the peaks are considered to be equally spaced, and the peak interval of the peak nodes can be obtained.

[0137] It is worth noting that when the peaks are equally spaced, it indicates that the electromagnetic signal is stable. Therefore, the stability of the electromagnetic signal can be determined by the peak spacing.

[0138] In the embodiments of this application, by screening and filtering the peak nodes, more obvious signal features can be extracted, which improves the reliability of subsequent signal feature comparison and reduces the complexity of subsequent signal feature comparison.

[0139] The following explains the steps for determining whether an electromagnetic leakage signal exists in the target space based on a preset signal threshold, the peak spacing of the frequency domain signal, and multiple peak nodes. Figure 9 As shown, the above step S201 includes:

[0140] S901: Compare the amplitude of multiple peak nodes with the second preset amplitude threshold.

[0141] Optionally, after identifying the peak nodes, the amplitude of multiple peak nodes can be compared with a second preset amplitude threshold, which can be preset with reference to electromagnetic protection and confidentiality standards.

[0142] For example, electromagnetic protection and confidentiality standards can be shown in Table 1.

[0143] Table 1

[0144] BMB2-1998 Test method and safety criterion for electromagnetic leakage emission of information equipment in use BMB3-1999 Technical requirement and test method for electromagnetic shielding room handling classified information BMB4-2000 Technical requirement and test method for electromagnetic interference equipment BMB5-2000 Protection requirement for electromagnetic leakage emission of classified information equipment in use BMB6-2001 Limit value for electromagnetic leakage emission of cryptographic equipment BMB7-2001 Test method for electromagnetic leakage emission of cryptographic equipment BMB7.1-2001 Test method for electromagnetic leakage emission of telephone cryptographic equipment BMB19-2006 Technical requirement and test method for electromagnetic leakage emission shielding cabinet GGBB1-1999 Limit value for electromagnetic leakage emission of information equipment GGBB2-1999 Test method for electromagnetic leakage emission of information equipment

[0145] S902: Based on the comparison results and the target leakage judgment strategy, determine whether there is an electromagnetic leakage signal in the target space.

[0146] Optionally, the target leakage determination strategy can refer to the electromagnetic protection and confidentiality standards in Table 1 to determine whether there are electromagnetic leakage signals in the target space under various scenarios.

[0147] The following describes the steps for restoring the electromagnetic signal to obtain an initial image of the electromagnetic signal, as described above. Figure 10 As shown, the above step S202 includes:

[0148] S1001: Stores electromagnetic signals as phase-amplitude data.

[0149] Optionally, when an electromagnetic leakage signal is detected in the space, the signal can be intercepted by a signal receiver and saved as phase-amplitude data (i.e., IQ data).

[0150] S1002: Determine the amplitude data of the electromagnetic signal based on a subset of the phase-amplitude data.

[0151] Optionally, a subset of the field frequency period (e.g., the period of a 60Hz screen refresh rate is 1 / 60 second) can be extracted from the IQ data, and a set of amplitudes can be calculated from it, which can then be used as the amplitude data of the electromagnetic signal.

[0152] It should be noted that because the level of a video signal is related to both the pixel value and the amplitude of the IQ signal, the pixel value can be represented by the amplitude.

[0153] For example, the amplitude can be calculated as shown in equation (3):

[0154]

[0155] Where I represents phase and Q represents amplitude.

[0156] S1003: Obtain intermediate amplitude data based on amplitude data.

[0157] It is worth noting that, in order to reconstruct the image, the number of data points in the amplitude sequence should be the same as the number of pixels in a frame of the image. However, in reality, due to the inconsistent sampling rates of different device models, the number of data points collected within the same period is also inconsistent. Therefore, when the number of data points is greater than the total number of pixels in a frame of the image, the amplitude sequence is resampled; otherwise, it is interpolated to make up the length.

[0158] For example, the interpolation algorithm can be a linear interpolation algorithm, as shown in equation (4) below:

[0159] Y=Y1+(Y2-Y1)×(X-X1) / (X2-X1) (4)

[0160] S1004: Based on the resolution information, the intermediate amplitude data is rearranged to obtain the initial image of the electromagnetic signal.

[0161] Optionally, the resolution information can be determined from the field synchronization signal and the line synchronization signal in the aforementioned synchronization signals.

[0162] Optionally, the intermediate amplitude data can be combined with the display resolution information to reconstruct a two-dimensional array, which can then be displayed as an image to obtain the initial image of the electromagnetic signal.

[0163] For example, such as Figure 11 As shown in the figure, the left side of the figure is the monitor screen, and the right side is a graph showing the relationship between the pixel values ​​on the screen and their corresponding RGB signals. The pixel values ​​are the values ​​in the two-dimensional array obtained by reconstructing the intermediate amplitude data.

[0164] In this embodiment of the application, by restoring the electromagnetic signal to obtain the corresponding image, the electromagnetic signal can be visualized, thereby quickly understanding the content of the electromagnetic signal.

[0165] The following describes the steps for correcting the initial image based on the synchronization signal extracted from the electromagnetic signal to obtain the corrected image. Figure 12 As shown, it includes:

[0166] S1201: The initial image is longitudinally corrected based on the field synchronization signal in the synchronization signal to obtain the intermediate corrected image.

[0167] Optionally, the field synchronization signal can be extracted by bandpass filtering, and the initial image can be corrected for vertical axis offset to obtain an intermediate corrected image.

[0168] S1202: Perform horizontal correction on the intermediate corrected image based on the horizontal synchronization signal in the synchronization signal to obtain the corrected image.

[0169] Optionally, the travel synchronization signal can be extracted by bandpass filtering to correct the horizontal offset of the initial image.

[0170] For example, when correcting the initial image, the diagram illustrating the changes in the image can be as follows: Figure 13 As shown.

[0171] In this application, by correcting the initial image, the electronic device can easily identify the starting position of text information in the image, reducing the complexity of subsequent text information recognition.

[0172] The following describes the steps for extracting information from the corrected image, obtaining the text information of the corrected image, determining whether the text information of the corrected image is risky based on a preset risk strategy, and outputting the corresponding alarm information if it is. Figure 14 As shown, the above step S204 includes:

[0173] S1401: Use a character recognition algorithm to extract information from the corrected image to obtain the text information of the corrected image.

[0174] Optionally, an image recognition algorithm can be used to obtain the text information in the image after correction.

[0175] It is worth noting that multiple images may be reconstructed based on electromagnetic signals. For images without text information, a coarse filter can be performed first, and then text can be extracted from images containing text information.

[0176] S1402: Extract the text information to be matched from the text information of the corrected image.

[0177] Optionally, the text information in the corrected image may include various types, such as Chinese characters, numbers, and letters. Not all text information may have actual meaning. Therefore, the text information with actual meaning can be extracted to obtain the text information to be matched.

[0178] For example, Chinese characters or letters can be used as the text information to be matched.

[0179] S1403: Match the text information to be matched with the preset risk strategy based on the preset matching algorithm.

[0180] Optionally, the preset matching algorithm can be a regular expression matching algorithm or a deep learning matching algorithm. By using the preset matching algorithm, the similarity between the text information to be matched and the risk information in the preset risk strategy can be determined.

[0181] Optionally, the preset risk strategy may include risk information, such as risk words, risk number combinations, or other risk characters determined by the user. This application does not impose any restrictions on this.

[0182] S1404: If the text information to be matched matches the risk strategy, then output the alarm information corresponding to the text information of the corrected image.

[0183] Optionally, if the text information to be matched successfully matches the risk strategy, it indicates that there is a risk of leakage of the text information to be matched. At this time, the electronic device can output the alarm information corresponding to the text information of the corrected image to prompt the user to check and deal with the electromagnetic leakage signal.

[0184] In this embodiment of the application, by identifying and screening the text information in the restored image, electromagnetic leakage signals that pose a risk can be identified in a timely manner, thereby improving the efficiency of electromagnetic signal detection.

[0185] Based on the same inventive concept, this application also provides an electromagnetic signal monitoring device corresponding to the electromagnetic signal monitoring method. Since the principle of the device in this application is similar to the electromagnetic signal monitoring method described above in this application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0186] Reference Figure 15 The diagram shown is a schematic of an electromagnetic signal monitoring device provided in an embodiment of this application. The device includes: a signal analysis module 1501, a signal restoration module 1502, an image correction module 1503, and an image analysis module 1504, wherein:

[0187] The signal analysis module 1501 is used to: perform time-frequency domain conversion on the electromagnetic signal in the target space to obtain the frequency domain signal of the electromagnetic signal, extract features from the frequency domain signal to obtain the peak interval and multiple peak nodes of the frequency domain signal, and determine whether there is an electromagnetic leakage signal in the target space based on the preset signal threshold, the peak interval and multiple peak nodes of the frequency domain signal.

[0188] The signal restoration module 1502 is used to: if so, restore the electromagnetic signal to obtain an initial image of the electromagnetic signal, the initial image including: text information corresponding to the electromagnetic signal;

[0189] Image correction module 1503 is used to: perform image correction on the initial image based on the synchronization signal extracted from the electromagnetic signal to obtain the corrected image;

[0190] The image analysis module 1504 is used to: extract information from the corrected image to obtain the text information of the corrected image, and determine whether the text information of the corrected image belongs to risk information according to the preset risk strategy. If so, it outputs the alarm information corresponding to the text information of the corrected image.

[0191] Optionally, the signal analysis module 1501 is specifically used for:

[0192] By performing second-order difference processing on the frequency domain signal, multiple initial peak nodes corresponding to the frequency domain signal are obtained;

[0193] Based on the initial peak nodes, determine the peak spacing and multiple peak nodes of the frequency domain signal.

[0194] Optionally, the signal analysis module 1501 is specifically used for:

[0195] Based on the first preset amplitude threshold and the amplitude of each initial peak node, multiple initial peak nodes are filtered to obtain multiple selectable peak nodes;

[0196] Multiple peak node sets are determined sequentially using a sliding window, and at least one optional peak node is determined sequentially from each peak node set as a peak node. The peak node set includes multiple optional peak nodes that are sequentially adjacent.

[0197] Differential calculations are performed on multiple peak nodes to obtain the peak interval of the peak nodes.

[0198] Optionally, the signal analysis module 1501 is specifically used for:

[0199] Compare the amplitudes of multiple peak nodes with a second preset amplitude threshold;

[0200] Based on the comparison results and the target leakage determination strategy, it is determined whether there is an electromagnetic leakage signal in the target space.

[0201] Optionally, the signal restoration module 1502 is specifically used for:

[0202] Storing electromagnetic signals as phase-amplitude data;

[0203] The amplitude data of the electromagnetic signal is determined based on a subset of the phase-amplitude data;

[0204] Based on the amplitude data, the intermediate amplitude data is obtained;

[0205] Based on the resolution information, the intermediate amplitude data is rearranged to obtain the initial image of the electromagnetic signal.

[0206] Optionally, the image correction module 1503 is specifically used for:

[0207] The initial image is longitudinally corrected based on the field synchronization signal in the synchronization signal to obtain the intermediate corrected image;

[0208] The intermediate corrected image is horizontally corrected based on the horizontal synchronization signal in the synchronization signal to obtain the corrected image.

[0209] Optionally, the image analysis module 1504 is specifically used for:

[0210] The text information of the corrected image is obtained by using a character recognition algorithm.

[0211] Extract the text information to be matched from the text information of the corrected image;

[0212] The text information to be matched is matched with the preset risk strategy based on the preset matching algorithm;

[0213] If the text information to be matched matches the risk strategy, then the alarm information corresponding to the text information in the corrected image will be output.

[0214] The processing flow of each module in the device and the interaction flow between each module can be referred to the relevant descriptions in the above method embodiments, and will not be detailed here.

[0215] This application's embodiments analyze electromagnetic signals within a space to determine the presence of electromagnetic leakage signals. When leakage is detected, the electromagnetic signal is reconstructed to obtain an image. Information is extracted from the image to obtain textual information. This textual information is then compared against a preset risk strategy to determine risk information and output an alarm. This electromagnetic signal monitoring system can promptly reconstruct electromagnetic signals upon detection of leakage, allowing users to immediately understand the signal's content. It also provides timely alarms when a risk is identified, improving the interaction between electromagnetic signal detection and the user. Furthermore, the detection results are visualized in text form, enhancing the efficiency of electromagnetic signal detection.

[0216] This application also provides an electronic device, such as... Figure 16The diagram shown is a schematic representation of an electronic device structure provided in an embodiment of this application, including: a processor 1601, a memory 1602, and a bus. The memory 1602 stores machine-readable instructions executable by the processor 1601 (e.g., ...). Figure 15 The device includes the signal analysis module 1501, signal restoration module 1502, image correction module 1503, and image analysis module 1504 (and their corresponding execution instructions). When the computer device is running, the processor 1601 and the memory 1602 communicate via a bus. When the machine-readable instructions are executed by the processor 1601, the above-mentioned electromagnetic signal monitoring method is performed.

[0217] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the electromagnetic signal monitoring method described above.

[0218] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and devices described above can be referred to the corresponding processes in the method embodiments, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be through some communication interfaces; the indirect coupling or communication connection of devices or modules can be electrical, mechanical, or other forms.

[0219] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0220] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes 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.

Claims

1. A method of electromagnetic signal monitoring, characterized by, The method includes: The electromagnetic signal in the target space is converted from time to frequency domain to obtain the frequency domain signal. Second-order difference processing is then performed on the frequency domain signal to obtain multiple initial peak nodes. Based on a first preset amplitude threshold and the amplitude of each initial peak node, the multiple initial peak nodes are filtered to obtain multiple selectable peak nodes. A sliding window is used to sequentially determine multiple peak node sets, and at least one selectable peak node is sequentially selected from each peak node set as the peak node. Each peak node set includes multiple sequentially adjacent selectable peak nodes. Difference calculation is performed on the multiple peak nodes to obtain the peak interval of the peak nodes. Based on a preset signal threshold, the peak interval of the frequency domain signal, and the multiple peak nodes, it is determined whether an electromagnetic leakage signal exists in the target space. If so, the electromagnetic signal is restored to obtain an initial image of the electromagnetic signal, which includes text information corresponding to the electromagnetic signal. The initial image is corrected based on the synchronization signal extracted from the electromagnetic signal to obtain the corrected image; Information is extracted from the corrected image to obtain the text information of the corrected image. Based on a preset risk strategy, it is determined whether the text information of the corrected image belongs to risk information. If so, the alarm information corresponding to the text information of the corrected image is output.

2. The method of claim 1, wherein, The step of determining whether an electromagnetic leakage signal exists in the target space based on a preset signal threshold and multiple peak nodes includes: The amplitudes of the multiple peak nodes are compared with a second preset amplitude threshold. Based on the comparison results and the target leakage determination strategy, it is determined whether there is an electromagnetic leakage signal in the target space.

3. The method of claim 1, wherein, The step of restoring the electromagnetic signal to obtain an initial image of the electromagnetic signal includes: The electromagnetic signal is stored as phase-amplitude data; The amplitude data of the electromagnetic signal is determined based on a subset of the phase-amplitude data; Based on the amplitude data, intermediate amplitude data is obtained; Based on the resolution information, the intermediate amplitude data is rearranged to obtain the initial image of the electromagnetic signal.

4. The method of claim 1, wherein, The step of performing image correction on the initial image based on the synchronization signal extracted from the electromagnetic signal to obtain the corrected image includes: The initial image is longitudinally corrected based on the field synchronization signal in the synchronization signal to obtain an intermediate corrected image; The intermediate corrected image is horizontally corrected based on the horizontal synchronization signal in the synchronization signal to obtain the corrected image.

5. The method according to any one of claims 1 to 4, characterized in that, The process involves extracting information from the corrected image to obtain its text information, and determining whether the text information is risky based on a preset risk strategy. If so, an alarm message corresponding to the text information is output, including: The text information of the corrected image is obtained by using a character recognition algorithm. Extract the text information to be matched from the text information of the corrected image; The matching algorithm is preset, and the to-be-matched text information is matched with the preset risk policy; If the to-be-matched text information matches the risk policy, the alarm information corresponding to the text information of the corrected image is output.

6. An electromagnetic signal monitoring device, characterized by Comprise: The signal analysis module is used for: converting the electromagnetic signal in the target space into a time-frequency domain to obtain a frequency domain signal of the electromagnetic signal, and performing second-order difference processing on the frequency domain signal to obtain a plurality of initial wave peak nodes corresponding to the frequency domain signal; According to the first preset amplitude threshold and the amplitudes of the initial wave peak nodes, the plurality of initial wave peak nodes are screened to obtain a plurality of selectable wave peak nodes; A plurality of wave peak node sets are determined in turn by using a sliding window, and at least one selectable wave peak node is determined from each wave peak node set in turn as the wave peak node, wherein the wave peak node set includes a plurality of selectable wave peak nodes that are adjacent in turn; the plurality of wave peak nodes are subjected to difference calculation to obtain a wave peak interval of the wave peak node, and it is determined whether there is an electromagnetic leakage signal in the target space according to a preset signal threshold, the wave peak interval of the frequency domain signal and a plurality of wave peak nodes; The signal restoration module is used for: if yes, performing signal restoration on the electromagnetic signal to obtain an initial image of the electromagnetic signal, wherein the initial image includes text information corresponding to the electromagnetic signal; The image correction module is used for: performing image correction on the initial image according to a synchronization signal extracted from the electromagnetic signal to obtain a corrected image; The image analysis module is used for: performing information extraction on the corrected image to obtain text information of the corrected image, and determining whether the text information of the corrected image belongs to risk information according to a preset risk policy, and if yes, outputting alarm information corresponding to the text information of the corrected image.

7. An electronic device, comprising: Comprise: A processor, a storage medium and a bus, the storage medium stores program instructions executable by the processor, when the electronic device is running, the processor and the storage medium communicate through the bus, the processor executes the program instructions to execute the steps of the electromagnetic signal monitoring method as claimed in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to execute the steps of the electromagnetic signal monitoring method as claimed in any one of claims 1 to 5.

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