Camera device detection method and related equipment

Abstract

The embodiment of the invention discloses a camera device detection method and related equipment, which are used for detecting a camera device under the condition of reducing the missing report rate of camera device detection. The method comprises the steps of collecting an electromagnetic signal generated by electronic equipment in a to-be-detected area, and if the electromagnetic signal meets characteristics corresponding to a harmonic signal of a crystal oscillator of the camera device, determining that the camera device exists in the to-be-detected area.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of camera detection, and more particularly, to a camera detection method, a camera detection device, a camera detection equipment, a computer readable storage medium, and a computer program product containing instructions. BACKGROUND

[0002] Pinhole cameras, miniature cameras, and other miniature photoelectric spying devices are currently the mainstream way to steal important information, and also have certain concealment characteristics. The popularity of various small devices has also seriously threatened the field of information security. Without the use of professional equipment for detection, it is difficult to detect by the naked eye alone.

[0003] Traditional camera detection methods mainly rely on the signal transmission of the camera. This method relies on the fact that the camera must send video signals through a wireless network (such as Wi-Fi, Bluetooth, 4G / 5G, etc.) in order to detect the camera. For example, a detection device scans the surrounding wireless signals, and if it identifies the video signals emitted by the camera, it determines that there is one.

[0004] However, this method can only detect cameras that are transmitting wireless signals, and cannot detect cameras that do not send wireless signals (such as cameras that only transmit signals through a wired connection or do not transmit signals). Therefore, the traditional camera detection method has a high false negative rate. SUMMARY

[0005] Embodiments of the present application provide a camera detection method, a camera detection device, a camera detection equipment, a computer readable storage medium, and a computer program product containing instructions, which can reduce the false negative rate of camera detection.

[0006] In a first aspect, embodiments of the present application provide a camera detection method, comprising:

[0007] Collecting electromagnetic signals generated by electronic devices in a to-be-detected area;

[0008] If the electromagnetic signals meet the characteristics corresponding to the harmonic signals of the camera device, it is determined that the to-be-detected area has a camera device; the frequency of the harmonic signals is an integer multiple of the frequency of the clock signal in the camera device.

[0009] In a second aspect, embodiments of the present application provide a camera detection device, comprising:

[0010] A collection unit for collecting electromagnetic signals generated by electronic devices in a to-be-detected area;

[0011] The determining unit is configured to determine that a camera device exists in the area to be detected if the electromagnetic signal satisfies the characteristics corresponding to the harmonic signal of the camera device; the frequency of the harmonic signal is an integer multiple of the frequency of the clock signal inside the camera device.

[0012] Thirdly, embodiments of this application provide a camera device detection apparatus, comprising:

[0013] Central processing unit, memory, input / output interfaces, wired or wireless network interfaces, and power supply;

[0014] The memory is either a short-term storage memory or a persistent storage memory;

[0015] The central processing unit is configured to communicate with the memory and execute instructions in the memory to perform the aforementioned camera device detection method.

[0016] Fourthly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a computer, cause the computer to perform the aforementioned camera device detection method.

[0017] Fifthly, embodiments of this application provide a computer program product containing instructions, which, when run on a computer, causes the computer to execute the aforementioned camera device detection method.

[0018] As can be seen from the above technical solutions, the embodiments of this application have the following advantages: The camera device detection method of this application determines the presence of a camera device by collecting electromagnetic signals and analyzing whether they conform to the characteristics corresponding to the harmonic signals of the camera device. Wherein, as long as the camera device is powered on, the electromagnetic signals it generates satisfy the characteristics corresponding to the harmonic signals. Therefore, regardless of whether the camera device transmits signals via wired or wireless means, or even if it does not transmit signals, as long as the camera device is powered on and working normally, its presence can be detected based on the characteristics of the harmonic signals, thereby reducing the false negative rate. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of a camera device detection method disclosed in an embodiment of this application.

[0020] Figure 2 for Figure 1 The illustrated embodiment shows a schematic diagram of one specific process of the camera device detection method.

[0021] Figure 3 for Figure 2 The illustrated embodiment shows a schematic diagram of one specific process of the camera device detection method.

[0022] Figure 4-1This is a spectrum diagram of the camera device in a smaller bandwidth in one embodiment of this application.

[0023] Figure 4-2 This is a spectrum diagram of the camera device in a larger bandwidth in another embodiment of this application.

[0024] Figure 4-3 This is a schematic diagram of the first frequency domain data in one embodiment of this application.

[0025] Figure 4-4 In order to be in Figure 4-3 A schematic diagram of frequency domain data with several peak points marked on it.

[0026] Figure 5 For this application Figure 3 The illustrated embodiment shows a specific flowchart of step S311.

[0027] Figure 6 for Figure 5 The illustrated embodiment is a schematic diagram of one specific process.

[0028] Figure 7 for Figure 6 The illustrated embodiment shows a specific flowchart of step S3c.

[0029] Figure 8 for Figure 7 The illustrated embodiment shows a detailed flowchart of step S3c2.

[0030] Figure 9 This is a schematic diagram of the first specific process of the camera device detection method in combination with the above embodiments.

[0031] Figure 10 for Figure 2 Another specific flowchart of the camera device detection method shown in the embodiment is illustrated.

[0032] Figure 11 This is a spectrum diagram of a second frequency domain data disclosed in one embodiment of this application.

[0033] Figure 12 for Figure 1 The illustrated embodiment shows a flowchart of a camera device detection method with added light stimulation.

[0034] Figure 13 for Figure 12 The illustrated embodiment is a schematic diagram of one specific process.

[0035] Figure 14-1 This is a time-domain diagram of a light-stimulated front camera device in an embodiment of this application.

[0036] Figure 14-2A time-domain graph after light stimulation in an embodiment of the present application.

[0037] Figure 14-3 A frequency spectrum graph before light stimulation in an embodiment of the present application.

[0038] Figure 14-4 A frequency spectrum graph after light stimulation and marking the light frequency in an embodiment of the present application.

[0039] Figure 15 A second specific flowchart of the camera detection method provided in the embodiments of the present application in combination with the above embodiments;

[0040] Figure 16 A third specific flowchart of the camera detection method provided in the embodiments of the present application in combination with the above embodiments;

[0041] Figure 17 A module diagram of a camera detection device in an embodiment of the present application.

[0042] Figure 18 A module diagram of a camera detection device in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The embodiments of the present application provide a camera detection method, a camera detection device, a camera detection equipment, a computer readable storage medium and a computer program product containing instructions, which can reduce the false negative rate of camera detection.

[0044] The traditional camera detection method mainly relies on the signal transmission of the camera. For example, if the camera transmits video signals through a wireless network, the detection equipment can determine whether the camera exists in the current detection area by identifying the wireless transmission signals. However, this method can only detect the camera that is transmitting wireless signals, and it is helpless for the camera that is connected through a wire or does not transmit signals wirelessly, and the false negative rate is high.

[0045] Therefore, in the embodiments of the present application, a camera detection method is provided, which analyzes and determines whether the camera exists by collecting the electromagnetic signals radiated by the camera itself. The electromagnetic signals radiated by the camera itself are inherent characteristics when the camera is working. As long as the camera is powered on and working, whether it transmits signals wirelessly or not, it will radiate detectable electromagnetic signals, which is not affected by specific scene conditions. Therefore, the embodiments of the present application are suitable for all types of cameras in any scene, significantly improving the accuracy, reliability and applicability of detection, and reducing the false negative rate.

[0046] Please refer to Figure 1The embodiment of the present application discloses a camera detection method, which can be applied to a camera detection device, for example, a processor in the camera detection device can execute the method. The camera detection device includes but is not limited to a portable device (such as a handheld detector), a fixedly installed detection device, or a detection device integrated in other systems, etc. The method can be used to detect whether there is a camera in the detection area. The camera is a device that can capture and record visual information of the surrounding environment, which is used to take pictures or record videos, for example, a camera. The method includes the following steps.

[0047] Step S100: Collecting electromagnetic signals generated by electronic devices in the detection area.

[0048] In an optional embodiment, the detection area represents a specific space or range that needs to be detected by the camera, which can be an indoor place (such as a conference room, a bedroom, etc.), or an outdoor area (such as a parking lot, a public place, etc.). The electronic device represents various electronic devices existing in the detection area, including but not limited to a camera, a mobile phone, a computer, etc. Among them, if the detection area has a camera (i.e., the electronic device is a camera), the camera will radiate a unique electromagnetic signal (i.e., the electromagnetic signal, the principle is described below), so whether the detection area has a camera can be determined based on the collected electromagnetic signal.

[0049] It can be understood that the way of collecting electromagnetic signals includes but is not limited to real-time collection, non-real-time collection, etc., which is not limited here. It should be noted that the electromagnetic signal here can be a signal directly radiated by the electronic device, or a signal processed (such as filtering, amplification, etc.) from the electromagnetic wave signal directly radiated by the electronic device. Assuming that the method is executed by the processor, for the former (i.e., the electromagnetic signal is the signal directly radiated by the electronic device), the receiving antenna can directly send the received signal to the processor. For the latter, the receiving antenna can first send the received signal to the subsequent signal processing circuit (for example, including a mixer, a filter, an amplifier) for processing, and then the signal processing circuit sends the processed signal to the processor.

[0050] Step S300: If the electromagnetic signal meets the characteristics of the harmonic signal of the camera, it is determined that the detection area has a camera. The frequency of the harmonic signal is an integer multiple of the frequency of the clock signal in the camera.

[0051] In an optional embodiment, the collected electromagnetic signal can be analyzed to determine whether the electromagnetic signal has the characteristics of the harmonic signal of the camera. If the electromagnetic signal meets the characteristics of the harmonic signal of the camera, it is determined that the detection area has a camera.

[0052] It needs to be understood that in the hardware system structure of the camera, a standard external crystal oscillator source is generally provided to provide a stable clock signal (such as a pixel clock, an internal processing clock (ISP), a data interface clock, and a frequency of 27 MHz, 24 MHz) for the image sensor. The clock signal usually generates a harmonic signal. At the same time, due to the existence of nonlinear elements in the circuit of the camera, when the clock signal passes through the nonlinear element, the harmonic signal is amplified due to the modulation or nonlinear effect in the circuit, that is, the energy of the harmonic signal is stronger, and the harmonic signal is more likely to be detected. Therefore, the camera can be identified by acquiring the harmonic signal.

[0053] It needs to be pointed out that the harmonic signal can only include the harmonic signal (assuming that the frequency of the clock signal is 27 MHz, the harmonic signal is, for example, 297 MHz), or a signal including the harmonic signal and having a certain bandwidth. The characteristics corresponding to the harmonic signal refer to the characteristics of the harmonic signal radiated by the camera, such as the frequency distribution law of the harmonic signal, the energy distribution law of the harmonic signal, the distribution law of the harmonic signal in the time domain, etc. Therefore, if the electromagnetic signal collected is radiated by the camera, the electromagnetic signal must have the characteristics corresponding to the harmonic signal, so that it can be determined that the camera exists in the detection area. For example: the camera detection device internally pre-stores the characteristics corresponding to the harmonic signal of the camera, and in actual detection, the collected electromagnetic signal is compared with the stored characteristics corresponding to the harmonic signal. If it is judged that the two are consistent, it can be determined that the camera exists in the detection area, that is, the emission source (i.e. electronic equipment) of the currently collected electromagnetic signal is the camera.

[0054] It is worth mentioning that the camera device detection method of this application determines the presence of a camera device by collecting electromagnetic signals and analyzing whether they conform to the characteristics of the camera device's harmonic signals, regardless of whether the camera device transmits wireless signals. Therefore, regardless of whether the camera device transmits signals via wired or wireless means, or even if it does not transmit signals at all, as long as the camera device is powered on and working normally, it will generate harmonic signals and can be detected. In other words, this application embodiment can detect camera devices that traditional technologies cannot detect, and can comprehensively and accurately detect actual camera devices with a low false alarm rate. Furthermore, this application embodiment determines the presence of a camera device by judging whether the electromagnetic signals conform to the harmonic signal characteristics of the camera device, which can more accurately identify the camera device signals, thereby improving the accuracy and reliability of detection and reducing the false alarm rate. Furthermore, this application embodiment is applicable to all types of camera devices, whether digital or analog, and regardless of the transmission method used or whether real-time signal transmission is performed, as long as the camera device is powered on and working normally, it will generate such harmonic signals. Therefore, the method of this application embodiment has wider applicability. Furthermore, since the harmonic signals of the camera device's crystal oscillator are an inherent characteristic of the camera device during operation and are not affected by specific scene conditions, detectable harmonic signals will be generated as long as the camera device is powered on. Therefore, the embodiments of this application are applicable to all types of camera devices under any scene conditions, significantly improving the accuracy, reliability, and applicability of camera device detection, and reducing the false negative rate of camera device detection.

[0055] In one optional implementation, determining whether an electromagnetic signal possesses characteristics corresponding to a harmonic signal can be achieved by performing real-time analysis on the acquired electromagnetic signal. Thus, by acquiring electromagnetic signals in real time and analyzing their compliance with the harmonic signal characteristics of the camera device's crystal oscillator, the presence of the camera device can be determined in real time, improving the timeliness and efficiency of camera device detection.

[0056] It is understandable that other reasonable methods for determining whether an electromagnetic signal has the characteristics corresponding to a harmonic signal could be other methods, such as non-real-time judgment of non-real-time acquired electromagnetic signals, which are not limited here.

[0057] In one alternative implementation, such as Figure 2 As shown, after acquiring the electromagnetic signals generated by the electronic device in the area to be detected, i.e. after step S100 above, the method further includes step S200: converting the electromagnetic signals into frequency domain data.

[0058] Accordingly, step S300 can be step S310: if the frequency domain data satisfies the set frequency distribution law corresponding to the harmonic signal of the camera device, then it is determined that there is a camera device in the area to be detected.

[0059] It can be understood that the collected electromagnetic signal can be frequency domain data that can be directly used for comparison with the stored characteristic corresponding to the harmonic signal, or can be time domain data. If the electromagnetic signal is frequency domain data, the above step S200 does not need to be performed. If the electromagnetic signal is time domain data, the electromagnetic signal can be converted into frequency domain data by FFT (Fast Fourier Transformation) or the like.

[0060] It needs to be understood that whether it is a digital camera or an analog camera, image information must be acquired through pixel scanning of an image sensor. The specific way is to convert the captured light signal into an electric signal and process the electric signal to form an image. During the pixel scanning of the image sensor, specific information will be generated, including F0 (set harmonic), Fm (total number of lines scanned per second by the camera) and Fp (frame rate of the camera), which will be modulated onto the harmonic signal, so that the harmonic signal has a specific frequency distribution rule (i.e. the above-mentioned set frequency distribution rule). The following is a specific explanation.

[0061] 1. For F0 (set harmonic): F0 is the set harmonic of the camera, that is, the harmonic of the crystal oscillator of the camera. The crystal oscillator of the camera provides a stable reference clock signal for the image sensor. In addition, the frequencies of the reference clock signals generated by the crystal oscillators of different models of cameras can be different. These differences will be amplified many times in the harmonics after the non-linear element, and the higher the order, the greater the difference.

[0062] 2. For Fm (total number of lines scanned per second by the camera): Fm is determined by Fp (frame rate of the camera), Rp (Pixel Rows, number of pixel rows, i.e. how many rows of pixels the image sensor has) and Rb (Blanking Rows, number of blanking rows), and the calculation formula is Fm = Fp x (Rp + Rb). Rb is one or more rows scanned in addition to the pixel rows during the scanning process of each frame of image. Rb specifically refers to a signal in a video signal used to eliminate the interference lines between the scanning lines on the display that are not visible, which is usually one or more rows inserted during the scanning process of each frame, with the purpose of avoiding visible horizontal lines or flicker when the display is re-scanned. In addition, even if the frame rates of the cameras are the same, different numbers of pixel rows and blanking rows will result in different Fm.

[0063] 3. For Fp (frame rate of the camera): Fp of different cameras can be different. Fp reflects the number of times the camera captures a complete picture per second, which is an important characteristic parameter of the camera.

[0064] It needs to be understood that as long as the camera device, Fm, Fp will be modulated to F0, therefore, as long as the judgment frequency domain data exists F0 modulated with Fm, or F0 modulated with Fp, or F0 modulated with Fm and Fp at the same time, the characteristics can be determined to be detected region exists camera device. That is, the frequency distribution law can include but not limited to "F0 modulated with Fm", "F0 modulated with Fp" and "F0 modulated with Fm and Fp" and other camera device specific frequency distribution law, not limited here. For example: for the distribution law of F0 modulated with Fm, if it is determined that the frequency domain data exists 297MHz (one kind of F0), and on the left and right of 297MHz frequency point, each appears a frequency point with equal frequency distance (all Fm) of 297MHz frequency point, it can be determined that there is a camera device.

[0065] It is worth mentioning that after the collected electromagnetic signal is converted into frequency domain data, the distribution law of electromagnetic signal in frequency domain can be more clearly identified. Because the frequencies of F0, Fm and Fp are different, it is easier to identify in the frequency domain. Therefore, by analyzing the distribution law of electromagnetic signal in frequency domain, the presence of camera device can be more easily identified, thereby the detection efficiency can be improved.

[0066] Next, the specific principles of identifying camera device according to the two frequency distribution laws of F0 modulated with Fm and F0 modulated with Fp will be described respectively.

[0067] As shown in Figure 3 In one embodiment, the camera device is identified according to the frequency distribution law of F0 modulated with Fm (hereinafter referred to as Fm detection scheme), and the specific principle is as follows.

[0068] The above step S100 specifically includes S110: collecting a first electromagnetic signal with a bandwidth less than a first threshold and a frequency of a set harmonic generated by an electronic device in a to-be-detected region. The above step S200 specifically includes step S210: converting the first electromagnetic signal into first frequency domain data. The above step S310 specifically includes step S311: if it is judged that there is a frequency point conforming to the formula F0±N×Fm in the first frequency domain data, it is determined that there is a camera device in the to-be-detected region. Wherein, F0 is a set harmonic, N is greater than or equal to 1, and Fm is the total number of lines scanned per second by the camera device.

[0069] Among them, the collected first electromagnetic signal can be specifically: the electromagnetic wave signal in the to-be-detected region collected under a certain bandwidth in the frequency band of the crystal oscillator harmonic of various camera devices.

[0070] Specifically, the electromagnetic wave signal generated by the electronic device in the to-be-detected region can be collected in the frequency band of the crystal oscillator harmonic of various camera devices in turn with a certain bandwidth (the bandwidth is less than the first threshold).

[0071] It needs to be understood that the bandwidth (BW) refers to the width of the frequency range of interest in the signal acquisition and analysis process, which determines the signal from which frequency to which frequency will be collected and analyzed. The first threshold value represents an upper limit value of the bandwidth. The bandwidth less than the first threshold value and the frequency of the first electromagnetic signal of the set harmonic, represents that the collected first electromagnetic signal is a narrowband signal covering the set harmonic frequency band. The purpose of such setting is: since the camera device is detected by analyzing the frequency distribution law of the harmonic signal, the frequency range of the collected electromagnetic signal is limited to the frequency range of the harmonic signal, which can quickly capture the frequency distribution law of the harmonic signal.

[0072] In addition, in this embodiment, the frequency band of the crystal oscillator harmonic of various camera devices can be set according to the common crystal oscillator frequency f0' (for example, 27MHz, 24MHz) of various camera devices. The relationship between the harmonic f0 and the crystal oscillator frequency f0' is f0=f0'xM, M is a positive integer. For example, the crystal oscillator frequency f0' = 27MHz, then its harmonic f0 can be 54MHz (M=2), 81MHz (M=3), etc. Since the harmonic signal will be amplified when passing through the nonlinear element, and usually the higher the order of the harmonic, the easier it is to be excited out, it is more convenient to detect, therefore, in this embodiment, the frequency band corresponding to the high harmonic is selected for analysis, for example, take 10≤M≤100.

[0073] Taking the set harmonic of the camera device crystal oscillator as the 11th harmonic (M=11) as an example, and the frequency of the crystal oscillator is f0'=27MHz, then the set harmonic is 297MHz (27MHzx11). If the bandwidth is 200kHz, it means that the signal in the range of 100kHz offset downward from the frequency of the harmonic signal 297MHz to 100kHz offset upward will be collected, that is, the frequency range of the collected signal is between 296.9MHz to 297.1MHz. That is, the first frequency domain data of the harmonic contains the frequency of the set harmonic and the frequency around it, which is used for further analyzing the existence of the camera device.

[0074] It should also be understood that there are different types of camera devices on the market, and different camera devices have different crystal frequencies (such as 27 MHz, 24 MHz, etc.), so the frequencies of the harmonics to be collected will also be different. For example, assume that there is a camera A whose crystal frequency is 27 MHz, and its harmonics can include the 2nd harmonic "54 MHz = (27 MHz x 2)", the 3rd harmonic "81 MHz = (27 MHz x 3)", and the 11th harmonic "297 MHz = (27 MHz x 11)". Another camera device B has a crystal frequency of 24 MHz, and its harmonics can include the 2nd harmonic "48 MHz = (24 MHz x 2)", the 3rd harmonic "72 MHz = (24 MHz x 3)", and the 10th harmonic "240 MHz = (24 MHz x 10)". When detecting, for camera A, 27 MHz, 54 MHz, 81 MHz, 297 MHz, etc. can be selected as the set harmonics for signal collection in turn. For camera B, 24 MHz, 48 MHz, 72 MHz, 240 MHz, etc. can be selected as the set harmonics for signal collection in turn. And for the data collected in each frequency band, the same detection method is performed, for example Figure 3 the method shown in

[0075] After the first electromagnetic signal is collected, FFT can be used for frequency domain conversion to obtain first frequency domain data. Next, the frequency distribution of the first frequency domain data can be analyzed, and if it has the characteristics of F0 modulation with Fm, it can be considered that the camera device exists in the detection area. After Fm is modulated to F0, a specific frequency distribution will be formed in the frequency domain, for example, as shown in Figure 4-1 , 4-2 , there will be a frequency distribution centered on F0, and there will be a frequency distribution that meets the formula F0 ± n x Fm (n is a positive integer). In other words, there are several pairs of frequency pairs on both sides of F0 whose frequency difference absolute value is an integer multiple of Fm (referred to as frequency pairs with Fm characteristics). For example, Figure 4-1 shows a pair of frequency pairs with Fm characteristics on both sides of F0, Figure 4-2 shows several pairs of frequency pairs with Fm characteristics on both sides of F0. This specific frequency distribution is an important characteristic of the camera device crystal harmonic signal, and is an inherent property of the camera device, so the camera device can be identified according to this characteristic.

[0076] It should be noted that in actual detection, it is sufficient to determine the presence of a frequency point that conforms to the formula F0±N×Fm (where N is greater than or equal to 1). For example, if a frequency pair conforming to the formula F0±Fm is found, the presence of a camera device can be directly determined. Similarly, if a frequency pair conforming to the formula F0±2Fm is found, the presence of a camera device can also be directly determined. Alternatively, to improve accuracy, the presence of both F0±Fm and F0±2Fm frequency pairs can also be determined.

[0077] Furthermore, the bandwidth can be greater than or equal to 4 times the Fm. The bandwidth value can be between 200KHz and 300KHz. After numerous tests by the inventors, a bandwidth value between 200KHz and 300KHz can detect 98% of the camera devices on the market.

[0078] Furthermore, the bandwidth is smaller than the absolute value of the frequency difference between the set harmonic and its adjacent harmonics. For example, assuming a crystal oscillator of 24MHz, there will be frequencies (24 + N × 24) MHz (i.e., harmonics) in the spectrum, where N is a multiple of 0.5. If the harmonic is 72MHz, then its adjacent harmonics are 60MHz and 84MHz. For instance, assuming the set harmonic is 297MHz and its adjacent harmonic is 283.5MHz, the absolute value of the frequency difference between them is 13.5MHz = 13500kHz. Therefore, the bandwidth of the above-mentioned acquisition is much smaller than 13500kHz. The advantage of this setting is that when searching for frequency pairs with Fm characteristics based on the set harmonic, the search only occurs in the frequency range near the set harmonic, without overlapping with the frequency ranges near other harmonics, thus improving the detection accuracy.

[0079] It is worth mentioning that by limiting the acquired electromagnetic signal to a bandwidth less than the first threshold, other irrelevant high-frequency noise and interference signals can be effectively filtered out. This allows the acquired electromagnetic signal to be more focused near the harmonic frequency of the camera device's crystal oscillator, thus more accurately capturing the frequency components with specific distribution patterns generated by the camera device during operation and avoiding excessive interference from irrelevant signals. Secondly, after converting the acquired electromagnetic signal into frequency domain data, the presence of a camera device is determined using the formula F0±N×Fm. This method fully utilizes the inherent characteristics of the camera device's operation. By detecting this specific distribution pattern in the frequency domain data, the signal generated by the camera device can be effectively distinguished from signals generated by other electronic devices, thereby improving the accuracy of the detection.

[0080] like Figure 5 As shown, in an optional implementation, step S311, i.e., if it is determined that there is a frequency point in the first frequency domain data that conforms to the formula F0±N×Fm, then it is determined that there is a camera device in the area to be detected, specifically includes the following steps.

[0081] Step S3a: determining the target peak point.

[0082] Step S3b: if it is determined that there is a frequency point conforming to the formula F0±NxFm in the first frequency domain data according to the frequency difference between the target peak point and the peak points on both sides of the target peak point, it is determined that the camera exists in the region to be detected.

[0083] It should be understood that the peak point refers to a frequency point with a relatively high signal amplitude (or power) relative to nearby frequency points, which usually represents the main frequency component in the signal, such as Figure 4-3 The harmonic signal of the camera crystal oscillator usually exhibits a significant peak in the frequency domain, and the target peak point refers to the peak point with a probability of being the set harmonic (F0) of the camera crystal oscillator selected in the current analysis process. For example, the frequencies are arranged in ascending order, and for the peak points on both sides of the target peak point, the frequency of the peak point on the left side of the target peak point is less than the frequency of the target peak point, and the frequency of the peak point on the right side of the target peak point is greater than the frequency of the target peak point.

[0084] The implementation process of step S3b can be: taking the target peak point as the center, checking the peak points on both sides of it, and calculating the frequency difference between the target peak point and these two side peak points. If it is found that the absolute value of the frequency difference between the two side peak points and the target peak point is an integer multiple of a certain specific value, and the farther away from the target peak point, the greater the absolute value of the frequency difference, it is considered that there is a frequency point conforming to the formula F0±NxFm, at this time, the specific value can be identified as Fm, and the target peak point can be identified as F0.

[0085] For example, assume that the first frequency domain data contains the following peak points (unit: MHz): 296.96, 296.97, 296.976, 296.98, 296.99, 297.0, 297.01, 297.02, 297.027, 297.03, 297.04. The specific implementation is that the selected peak point in the first frequency domain data, such as the highest peak point 297.0 MHz, is taken as the target peak point. Then the frequency difference between the target peak point and the peak points located on the right side of the target peak point can be determined in sequence, that is, the frequency differences between the peak points 297.01, 297.02, 297.03, 297.04 and the target peak point 297.0 are 0.01 MHz=10 kHz, 0.02 MHz=20 kHz, 0.03 MHz=30 kHz and 0.04 MHz=40 kHz respectively, that is, all are integer multiples of 10 kHz. And the frequency differences between the target peak point and the peak points located on the left side of the target peak point can be determined in sequence, that is, the frequency differences between the peak points 296.96, 296.97, 296.98, 296.99 and the target peak point 297.0 are -0.04 MHz=-40 kHz, -0.03 MHz=-30 kHz, -0.02 MHz=-20 kHz and -0.01 MHz=-10 kHz respectively, that is, all are integer multiples of -10 kHz. Then it can be determined that the frequencies of the peak points on the left side gradually decrease at intervals of 10 kHz and the frequencies of the peak points on the right side gradually increase at intervals of 10 kHz with 297.0 MHz as the center, so it can be considered that the target peak point 297.0 MHz is F0 and the frequency difference 10 kHz is determined as Fm. If the frequency difference does not conform to the above rule, it is considered that there is no frequency point conforming to the formula F0±N×Fm. For example, assume that the frequency differences between the peak points 292.01, 293.02, 294.027, 295.03, 296.04 on the right side and the target peak point 297.0 are not all integer multiples of a certain specific value. Or, the frequency differences between the peak points 277.96, 280.97, 282.976, 286.98, 289.99 on the left side and the target peak point 290.0 are also not all integer multiples of a certain specific value, then it is considered that there is no frequency point conforming to the formula F0±N×Fm in the first frequency domain data.

[0086] In this embodiment, by determining the target peak point, the search range can be quickly narrowed down, and then only the peak points around the target peak point need to be calculated for the frequency difference, so as to quickly judge whether there is a frequency point conforming to the formula F0±N×Fm. The calculation efficiency of this method is relatively high, which can quickly process a large amount of frequency domain data and accurately detect whether there is a camera device.

[0087] In an alternative implementation, as Figure 6As shown, the step S3a can be step S3a1: taking the highest peak point in the first frequency domain data as the target peak point. Correspondingly, the step S3b can specifically include: step S3c: if it is judged that there is a frequency point with a frequency complying with the formula F0±NxFm in the first frequency domain data according to the frequency difference between the target peak point and the peak points located on both sides of the target peak point, it is determined that the camera device exists in the to-be-detected region. Step S3d: if it is unable to judge that there is a frequency point with a frequency complying with the formula F0±NxFm in the first frequency domain data according to the frequency difference between the target peak point and the peak points located on both sides of the target peak point, taking other peak points in the first frequency domain data as new target peak points. Step S3e: judging whether there is a frequency point complying with the formula F0±NxFm in the first frequency domain data according to the frequency difference between the new target peak point and the peak points located on both sides of the new target peak point.

[0088] The highest peak point can be a peak point with the highest amplitude or power. The implementation of taking the highest peak point in the first frequency domain data as the target peak point can be, for example, finding all the peak points in the first frequency domain data. All the peak points are sorted in descending order according to the amplitude, and the first M peak points are selected as candidate peak points. These candidate peak points are used to update the target peak point. In order to avoid missing possible harmonic frequencies, M should not be too small, and in an embodiment, M can be set to a natural number greater than 5. Then, the highest peak point is taken as the target peak point. For example Figure 4-4 As shown, the peak points P1, P2, P6, P3 and P9 with the top 5 amplitudes are taken as candidate peak points to update the target peak point.

[0089] It can be understood that the way of selecting candidate peak points can also be to filter out the peak points with amplitudes greater than a preset amplitude value from all the peak points, and then take the filtered peak points as candidate peak points. The preset amplitude value can be a fixed value or a dynamic value adjusted in real time according to different environments, and the specific value of the preset amplitude value is not limited here. It can be understood that the implementation of taking the highest peak point in the first frequency domain data as the target peak point can also be other reasonable implementations, and the specific implementation is not limited here.

[0090] It can be understood that if it is judged that the highest peak point and the peak points on both sides thereof do not conform to the formula F0±NxFm, other peak points in the first frequency domain data can be taken as new target peak points for analysis. The implementation of taking other peak points in the first frequency domain data as new target peak points can be to select the peak points from the alternative peak points in the order of high to low in signal strength (such as the second highest peak point, the third highest peak point, etc.). Since the peak points with higher peak values are all likely to be harmonic signals of the camera device, after sorting according to the signal strength, the frequency points conforming to the formula F0±NxFm can be found quickly, unnecessary calculation is reduced, and the efficiency of camera device detection is improved. The implementation of taking other peak points in the first frequency domain data as new target peak points can also be to traverse all unmeasured peak points. Through the traversal manner, it can be ensured that all peak points are analyzed, and possible camera device signals can be avoided from being missed. In the case that the frequency domain data is complex and multiple electronic device signals are mixed, the comprehensiveness of camera device detection can be improved. The implementation of taking other peak points in the first frequency domain as new target peak points can also be other reasonable implementations of taking other peak points in the first frequency domain as new target peak points, which are not limited here. In summary, other peak points can be tried in turn until the peak points conforming to the formula are found.

[0091] Specifically, by identifying the highest peak point in the first frequency domain data as the starting point, it is determined whether it conforms to the formula F0±NxFm according to the frequency difference of the peak points on both sides. If it matches, it can be determined that there is a camera. If it cannot be matched, other peak points are selected as new target peak points in turn and further detection is continued according to the same method to ensure the comprehensiveness of the camera detection. For example, assuming that the first frequency domain data contains the following frequency peak points (unit: MHz): 296.96, 296.97, 296.976, 296.98, 296.99, 297.0, 297.01, 297.02, 297.027, 297.03, 297.04. Among them, the peak points with the top 5 amplitudes are: 297.01, 297.0, 296.99, 297.02, 297.027, and these 5 peak points are the candidate peak points. Assuming that the peak point with the highest amplitude is 297.01, 297.01 is first selected as the target peak point. Then it can be determined that the frequency difference between the target peak point 297.01 and the peak points on both sides is not an integer multiple of a certain value, so it cannot be determined that there is a frequency point in the first frequency domain data that conforms to the formula F0±NxFm. At this time, the peak point 297.0 with the second highest amplitude value can be selected as a new target peak point, and then the frequency difference between the new target peak point 297.0 and the peak points on both sides can be determined in turn. If the absolute value of the frequency difference is an integer multiple of 10 kHz, it is considered that there is a frequency point in the first frequency domain data that conforms to the formula F0±NxFm, and the frequency 297.0 MHz of the new target peak point is F0 and 10 kHz is Fm. In addition, if the target peak point 297.0 cannot determine whether there is a camera, other peak points in the candidate peak points are selected as new target peak points, and the cycle is executed in turn. If all the peak points in the candidate peak points are traversed, it is still not possible to determine whether there is a camera, and the above step S110 can be re-executed, or other detection scheme steps can be executed.

[0092] It is worth mentioning that starting from the highest peak point for analysis can quickly focus on the strongest frequency component in the signal, which helps to accurately locate the characteristic signal of the camera device, can improve the efficiency of camera device detection, and can avoid wasting computing resources on weaker signal components. Secondly, if the highest peak point does not conform to the formula F0±NxFm, by switching to other peak points for further analysis, the comprehensiveness of camera device detection can be ensured, and the flexibility and accuracy of camera device detection can be improved by avoiding missing cameras due to false judgment of a single peak point.

[0093] For the above step S3c, as Figure 7As shown, in an optional embodiment, if it is determined that there is a frequency point in the first frequency domain data that meets the formula F0±NxFm according to the frequency difference between the target peak point and the peak points on both sides of the target peak point, it is determined that the camera exists in the to-be-detected region, which can include the following steps S3c1-S3c4.

[0094] Step S3c1: The absolute value of the frequency difference between the first peak point and the target peak point is recorded as fm1. The first peak point is the peak point on the first side of the target peak point and has the minimum absolute value of the frequency difference with the target peak point.

[0095] Step S3c2: If there is a peak point on the second side of the target peak point that has an absolute value of the frequency difference with the target peak point equal to fm1, it is determined that the camera exists in the to-be-detected region. And fm1 is Fm, and the target peak point is F0.

[0096] It should be understood that the first side is the left side or the right side of the target peak point. If the first side is the left side, then the second side is the right side. If the first side is the right side, then the second side is the left side. The specific first side and second side of the target peak point are not limited by the embodiments of the present application. For example, in Figure 4-2 , the frequency of the peak point on the left side of the peak point F0 is less than the frequency of the peak point F0, and the frequency of the peak point on the right side of the peak point F0 is greater than the frequency of the peak point F0.

[0097] Specifically, P peak points near the target peak point can be found to form a test array. Among them, there are P / 2 peak points on the first side and the second side of the target peak point. In order to reduce false negatives, the number of peak points on both sides should be greater than or equal to a preset number, for example, P is greater than or equal to 50. The first peak point is on the first side of the target peak point and is closest to the target peak point. In this embodiment, the absolute value of the frequency difference between the first peak point and the target peak point is recorded as fm1, and then it is determined whether there is a peak point on the second side whose absolute value of the frequency difference with the target peak point is also fm1. If so, it is considered that fm1 is the Fm of the camera, which represents the existence of the camera. For example, Figure 4-4 As shown, assuming that P1 is the target peak point first, P2 is the first peak point, and the absolute value of the frequency difference between P2 and P1 is 10 kHz, and then it is determined that the absolute value of the frequency difference between P6 on the right side of P1 and P1 is also 10 kHz, it is considered that the 10 kHz is the Fm of the camera, and the frequency of P1 is the set harmonic F0 of the camera.

[0098] It should be understood that the test array contains P peak points selected from the peak point array and closest to the target peak point. These peak points are used in the actual detection operation to determine whether there is a frequency point that meets the formula F0±N×Fm. By limiting the detection range to the P peak points closest to the target peak point, the calculation and comparison of the frequency difference can be more efficient, and the detection efficiency can be improved.

[0099] In an alternative embodiment, the specific implementation of step S3c includes the following steps after step S3c1, as shown in the figure. Figure 7

[0100] Step S3c3: If there is no peak point on the second side of the target peak point whose absolute value of the frequency difference from the target peak point is equal to fm1, the absolute value of the frequency difference between the second peak point and the target peak point is recorded as fm2. The second peak point is on the first side of the target peak point, and the absolute value of the frequency difference between the second peak point and the target peak point is greater than the absolute value of the frequency difference between the first peak point and the target peak point.

[0101] Step S3c4: If there is a frequency point on the second side of the target peak point whose absolute value of the frequency difference from the target peak point is equal to fm2, it is determined that the camera exists in the to-be-detected region. And fm2 is Fm, and the target peak point is F0.

[0102] It should be understood that the second peak point can be any peak point on the first side of the target peak point whose absolute value of the frequency difference from the target peak point is greater than fm1, or the second closest peak point on the first side of the target peak point, or other reasonable peak point whose absolute value of the frequency difference from the target peak point is greater than fm1, which is not limited here.

[0103] If there is no peak point on the second side of the target peak point whose absolute value of the frequency difference from the target peak point is equal to fm1, it means that fm1 is not Fm of the camera, and a new value needs to be found for verification. In this embodiment, the second closest peak point on the first side of the target peak point is recorded as the second peak point, and the absolute value of the frequency difference between the second peak point and the target peak point is recorded as fm2, i.e., fm2 is the updated to-be-verified value. If there is a peak point on the second side of the target peak point whose absolute value of the frequency difference from the target peak point is equal to fm2, it is determined that there is a frequency point in the first frequency domain data that meets the formula F0±N×Fm, and fm2 is Fm and the target peak point is F0. If not, the third, fourth, and P / 2 closest peak points on the first side are found in turn, and the above steps are repeated.

[0104] ​In one alternative implementation, to verify Fm, such as Figure 8 As shown, step S3c2 above, that is, if there is a peak point on the second side of the target peak point with an absolute value of frequency difference equal to fm1, then it is determined that there is a camera device in the area to be detected, can specifically include the following steps A to C.

[0105] Step A: If there is a peak point on the second side of the target peak point whose absolute value of the frequency difference with the target peak point is equal to fm1, then proceed to step B.

[0106] Step B: Find the peak point on the first side of the target peak point where the absolute value of the frequency difference between the peak point and the target peak point is 2fm1.

[0107] Step C: If there is a peak point on the second side of the target peak point with an absolute frequency difference of 2fm1 from the target peak point, then it is determined that there is a camera device in the area to be detected.

[0108] In this embodiment, it is first determined that there exists a pair of peak points on both sides of the target peak point with an absolute frequency difference of fm1 from the target peak point. Then, fm1 is further verified to confirm whether it is necessarily Fm. Since the camera device has the characteristic of F0±n×Fm, if fm1 is Fm in the formula, then there should exist other peak points with an absolute frequency difference from the target peak point that is an integer multiple of fm1. Therefore, the further confirmation method in this embodiment is: determine whether there are peak points on both sides of the target peak point with an absolute frequency difference of 2fm1 from the target peak point. If so, it can be confirmed that fm1 is Fm. This step-by-step verification method can effectively filter out accidental similarities, reduce the possibility of misjudgment, and lower the false alarm rate.

[0109] It is understandable that, in order to further reduce the false alarm rate, it is also possible to further verify whether there are other peak points on both sides of the target peak point with an absolute frequency difference of fm1. The principle is similar to the above steps AC, so it will not be repeated here.

[0110] Next, in conjunction with the above embodiments, a complete and specific implementation of a camera device identification method based on the frequency distribution law of Fm modulated by F0 will be described, such as... Figure 9 As shown, the camera device detection method includes the following.

[0111] Step S1 (i.e., step S110 above): Collect a first electromagnetic signal with a bandwidth less than the first threshold and a frequency of a set harmonic generated by an electronic device within the area to be detected.

[0112] Step S2 (i.e., step S210 above): Convert the first electromagnetic signal into first frequency domain data.

[0113] Step S3 (i.e. the above-mentioned step S3a1): taking the highest peak point in the first frequency domain data as a target peak point.

[0114] Step S4 (i.e. the above-mentioned step S3c1): taking the absolute value of the frequency difference between the first peak point and the target peak point as fm1.

[0115] Step S5: judging whether there is a peak point in the peak points on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is equal to the above-mentioned fm1, if yes, executing the following step S8, if no, executing the following step S6.

[0116] In this step, the peak points on the second side of the target peak point are traversed, if it is judged that the absolute value of the frequency difference between a peak point and the target peak point is fm1, the following step S8 is executed (the principle can be referred to the above-mentioned step S3c2). If it is judged that none of the peak points on the second side of the target peak point (for example, all the P / 2 peak points on the second side of the target peak point) has the absolute value of the frequency difference with the target peak point equal to fm1, the following step S6 is executed.

[0117] Step S6 (i.e. the above-mentioned step S3c3): taking the absolute value of the frequency difference between the second peak point and the target peak point as fm2.

[0118] Step S7: judging whether there is a peak point in the peak points on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is equal to fm2, if yes, executing the following step S8, if no, executing step S9.

[0119] In this step, if it is judged that there is a peak point on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is fm2, step S8 is executed (the principle can be referred to the above-mentioned step S3c4). If it is judged that none of the peak points on the second side of the target peak point (for example, all the P / 2 peak points on the second side of the target peak point) has the absolute value of the frequency difference with the target peak point equal to fm2, the following step S9 is executed.

[0120] Step S9: updating the second peak point, and judging whether the second peak point is traversed, if yes, executing the following step S10, if no, continuing to execute the above-mentioned step S6.

[0121] In this step, a new peak point can be selected from the P / 2 peak points on the first side of the target peak point as a new second peak point, for example, Figure 4-4In the embodiment, if P1 is the current target peak point, the first peak point is P2, if there is no peak point on the second side of P1 which is symmetrical to P2 (the peak point symmetrical to P2 refers to the peak point whose frequency difference absolute value with P1 is the same as the frequency difference absolute value of P2 with P1), the second peak point can be updated to P3, and then it is judged whether there is a peak point on the second side of the target peak point which is symmetrical to P3 (i.e. the above step S6 is performed on the updated second peak point), if not, P4 is continuously taken as the new second peak point, and the cycle is continued until all P / 2 peak points on the first side of P1 are traversed, and then step S10 is performed.

[0122] Step S10: taking other peak points in the first frequency domain data as new target peak points. The step can refer to the above step S3d.

[0123] Step S11: judging whether the target peak point is traversed, if yes, step S1 is performed, if not, step S4 is performed.

[0124] In the embodiment, the target peak point can be selected from the above-mentioned peak points in turn, for example Figure 4-4 In the embodiment, the peak points include P1, P2, P6, P3, P9, if these peak points are taken as the target peak points in turn, and all of them are performed according to steps S4-S11, it is considered that the target peak point is traversed.

[0125] Step S8: judging that the camera exists in the to-be-detected region.

[0126] Next, the specific detection principle of the camera according to the frequency distribution rule that F0 is modulated by Fp (hereinafter referred to as “Fp detection scheme”) is introduced.

[0127] As shown in Figure 10 The step S100 of the above-mentioned camera detection method specifically includes:

[0128] Step S120: collecting a second electromagnetic signal in the to-be-detected region, the bandwidth of the second electromagnetic signal is less than a second threshold, and the frequency of the second electromagnetic signal is a set harmonic generated by the electronic device. The second threshold is less than the first threshold.

[0129] The above-mentioned step S200 specifically includes step S220: converting the second electromagnetic signal into second frequency domain data.

[0130] The above-mentioned step S310 specifically includes step S312: if there is a frequency point in the second frequency domain data which meets the formula F0±N×Fp, it is judged that the camera exists in the to-be-detected region. In the formula, F0 is a set harmonic, N is greater than or equal to 1, and Fp is the frame rate of the camera.

[0131] It needs to be understood that due to the uniqueness of F0 and Fp, the electromagnetic signal generated by the camera will form a specific frequency distribution rule in the frequency domain, such as in the second frequency domain data, there is a frequency point distribution conforming to the formula F0±n×Fp (n is a positive integer) centered on F0, as shown in Figure 11 This specific frequency distribution rule is an important feature of the camera crystal oscillator harmonic signal and is an inherent property of the camera operation. Such signal characteristics are usually generated by the camera.

[0132] Specifically, the acquisition method of the second electromagnetic signal and the second frequency domain data is basically the same as that of the first electromagnetic signal and the first frequency domain data in the Fm detection scheme, please refer to step S200 for details, the difference is that the bandwidth of the second electromagnetic signal is reduced. In addition, the set harmonics of the first electromagnetic signal and the second electromagnetic signal are the same, the first electromagnetic signal can be understood as including the set harmonic and a signal in a larger frequency range near the set harmonic, and the second electromagnetic signal can be understood as including the set harmonic and a signal in a smaller frequency range near the set harmonic.

[0133] Figure 11 A frequency spectrum diagram of the second frequency domain data disclosed in an embodiment of the present application. On this basis, the RBW (Resolution Bandwidth, resolution bandwidth) can also be reduced. For example, the frequency range of the second electromagnetic signal can be limited to a 2KHz range centered on the set harmonic of the camera crystal oscillator. Since Fp is smaller than Fm, the second electromagnetic signal has a smaller bandwidth in this embodiment, which can more accurately focus on the characteristics related to Fp and improve the sensitivity of identifying Fp. In addition, setting the RBW to a small value such as 2Hz means that the frequency resolution in the second frequency domain data reaches 2Hz, so that it can cover more types of cameras on the market, and also facilitate clear identification of the Fp characteristics in the second frequency domain data. As shown in Figure 11 For the camera, if Fp is modulated to F0, the frequency distribution rule of F0±n×Fp (n is a positive integer) will also appear, so whether the camera exists in the detection area can be determined by judging whether the second electromagnetic signal has this frequency distribution rule.

[0134] In this embodiment, after converting the acquired second electromagnetic signal into second frequency domain data, the presence of a camera device is determined by whether the second frequency domain data conforms to F0±N×Fp. It should be noted that in actual detection, it is sufficient to determine the presence of a frequency point conforming to the formula F0±N×Fp (N is greater than or equal to 1). For example, if a pair of frequencies conforming to the formula F0±Fp is found, the presence of a camera device can be directly determined. Alternatively, if a pair of frequencies conforming to the formula F0±2Fp is found, the presence of a camera device can also be directly determined. Alternatively, to improve accuracy, if both pairs of frequencies, F0±Fp and F0±2Fp, are found, the presence of a camera device can also be determined.

[0135] Specifically, Figure 10 In the Fp detection scheme shown, the principles of each step are the same as described above, except for the difference in bandwidth and the replacement of Fm with Fp. Figure 3 The illustrated embodiment. For example, the highest peak point is first selected as the target peak point. It is then determined whether there are peak points on both sides of the target peak point with the same absolute value of frequency difference. If so, the absolute value of the frequency difference is Fp, and the target peak point is F0. If not, other peak points are traversed. If, after traversing all peak points, no peak point with the same absolute value of frequency difference on both sides is found, the target peak point is changed, and the same judgment process is repeated. If no target peak point is found after traversing all target peak points, step S120 is executed again.

[0136] This embodiment also makes full use of the characteristic of the camera device having Fp. By analyzing whether the second frequency domain data has a specific distribution pattern of frequency points of F0±N×Fp, it can effectively distinguish the signal generated by the camera device from the signal generated by other electronic devices, thereby improving the accuracy of detection.

[0137] It needs to be understood that the camera searching by using Fp and the camera searching by using Fm are both based on the specific frequency distribution rule of the camera crystal oscillator signal. In the specific implementation process, the implementation mode can be selected according to the actual detection scene or requirement. For example, since Fm is greater than Fp, the detection speed of the Fm detection scheme is obviously superior to that of the Fp detection scheme in the actual detection (for example, the detection time of the Fm detection scheme can be about 5 ms, and the detection time of the Fp detection scheme is about 0.2 s). Moreover, compared with Fp, the corresponding energy of the Fm modulated harmonic signal is greater, and the detection distance is also greater. Therefore, the Fm detection scheme is suitable for the scene that needs to quickly detect a large area. If a more accurate detection result is required, the Fm detection scheme and the Fp detection scheme can be used at the same time. If the camera cannot be detected by the Fm detection scheme, the Fp detection scheme can also be tried to supplement the detection.

[0138] It can be understood that when detecting the camera, the Fp detection scheme or the Fm detection scheme can be selected alone for camera detection, or both schemes can be used at the same time to further improve the accuracy of the detection result and reduce the false negative rate. Using the schemes at the same time means that the two schemes can be performed in parallel (at the same time) or sequentially. Parallel detection means that the Fm detection scheme and the Fp detection scheme are executed at the same time, that is, whether the frequency point distribution conforming to the formula F0±NxFm and F0±NxFp exists in the frequency domain data is judged at the same time. Since the two rules correspond to two independent attributes of the camera respectively, the detection can be performed at the same time without interfering with each other. Sequential detection means that whether the frequency point distribution conforming to the formula F0±NxFm (Fm detection scheme) exists is detected first, and if it is found, it is confirmed that the camera exists. If it is not found, whether the frequency point distribution conforming to the formula F0±NxFp (Fp detection scheme) exists is detected. Alternatively, if it is judged that the frequency point distribution conforming to the formula F0±NxFm exists, it can be further judged whether the frequency point distribution conforming to the formula F0±NxFp exists.

[0139] In order to further distinguish the camera and the electronic screen in the to-be-detected area, the light stimulation method needs to be used for further judgment to improve the accuracy of the camera detection result. As shown in FIG. 3, the step S300 includes the following specific steps. Figure 12

[0140] S320: If the electromagnetic signal meets the characteristics of the harmonic signal of the camera, a third electromagnetic signal generated by the electronic device in the to-be-detected area after accepting the variable frequency light stimulation is collected.

[0141] S500: If it is judged that the third electromagnetic signal has the characteristics corresponding to the light, it is determined that the to-be-detected area exists the camera. ​

[0142] It needs to be understood that if the electromagnetic signal satisfies the set frequency distribution rule corresponding to the harmonic signal of the camera (for example, F0±N×Fm, F0±N×Fp described above), it means that there is a suspicious device in the to-be-detected area, and the suspicious device can be a camera or an electronic screen. Since the electronic screen has similar characteristics as the camera, further light stimulation can be used to further confirm whether it is a camera.

[0143] Specifically, the image sensor in the camera converts the light signal into an electrical signal. The light stimulation will disturb the photoelectric conversion capability of the image sensor, that is, when the image sensor is subjected to light stimulation, the light signal will be converted into an electrical signal, and the electrical signal will radiate corresponding electromagnetic waves in the subsequent circuit conduction, especially after amplification. Therefore, whether the received electromagnetic wave (i.e., the third electromagnetic signal) has characteristics corresponding to the light can be determined after the light stimulation to identify the camera.

[0144] It also needs to be understood that when the camera is subjected to light stimulation, the electromagnetic signal radiated by the camera will exhibit specific changes corresponding to the light in the frequency domain or the time domain, such as the appearance of a frequency point with the same frequency as the light in the frequency domain, or the appearance of a specific amplitude change rule in the time domain. Therefore, the camera can be identified according to the characteristics of the third electromagnetic signal in the time domain or the frequency domain.

[0145] In this embodiment, the determination of whether the to-be-detected area has a camera by combining the determination of whether the electromagnetic signal has characteristics corresponding to the harmonic signal of the camera and the determination of whether the third electromagnetic signal has characteristics corresponding to the light stimulation can further exclude the interference of the electronic screen, thereby improving the accuracy of camera detection. In addition, the light stimulation is used for detection. If the distance to the camera is close, the light beam will produce a specific irradiation area when irradiating on a plane (such as a wall). When the user uses the camera detection device to perform light stimulation on the to-be-detected area, it can not only be determined whether there is a camera in the to-be-detected area, but also be determined that the camera is located in the irradiation area, thereby realizing directional detection (i.e., detecting the area where the camera is located). Moreover, the electromagnetic signal generated by the camera can penetrate the wall, and the light stimulation can also exclude the interference of the camera in other areas (assuming that there is no light stimulation, although there is no camera in the to-be-detected area, the camera in other areas can also emit electromagnetic signals, and once the electromagnetic signal is received, it will be mistaken as a camera in the to-be-detected area. Therefore, the to-be-detected area is stimulated by light, and if there is no camera in the to-be-detected area, the third electromagnetic signal will not have the characteristics of the light, so the interference of the camera in other areas can be excluded), which can quickly and accurately detect the position of the camera in the irradiation area.

[0146] In an alternative embodiment, the step S500 specifically comprises the following steps.

[0147] If it is determined that the amplitude of one or more time points in the time-domain curve corresponding to the third electromagnetic signal is greater than the set jitter threshold, it is determined that the camera exists in the to-be-detected region.

[0148] In this embodiment, the camera is identified by the time-domain characteristics of the third electromagnetic signal. The amplitude of one or more time points being greater than the set jitter threshold represents that the time-domain curve has obvious jitter, and the jitter has some amplitude that is obviously increased. For example, Figure 14-1 Before the light stimulation, the electromagnetic signal is relatively stable and has no obvious fluctuation. At this time, the electromagnetic signal only has the signal (such as the harmonic signal of the crystal oscillator) radiated by the camera itself. For example, Figure 14-2 After the light stimulation, the electromagnetic signal (i.e., the third electromagnetic signal) has obvious jitter. Therefore, if it is determined that the time-domain curve has jitter, it can be considered that the camera exists in the to-be-detected region.

[0149] In this embodiment, the amplitude jitter is determined by analyzing the time-domain curve, which can directly identify the response of the camera and improve the accuracy of camera detection.

[0150] In another embodiment, as shown in FIG. 4, Figure 13 after the step S320, the method further comprises a step S400 of converting the third electromagnetic signal into third frequency-domain data. Meanwhile, the step S500 specifically comprises a step S510 of determining that the camera exists in the to-be-detected region if it is determined that the third frequency-domain data has a frequency point that is the same as the frequency of the light.

[0151] In this embodiment, the camera is identified by the characteristics of the third electromagnetic signal in the frequency domain. The third electromagnetic signal can be converted into third frequency-domain data for identification. Under the light stimulation, if the electronic device is a camera, the third frequency-domain data of the camera will have a frequency point that is the same as the frequency of the light. This indicates that the camera has responded to the light stimulation, and thus the camera can be distinguished from other electronic devices. For example, Figure 14-3 a frequency-domain diagram of the electromagnetic signal before the light stimulation is shown in FIG. 5, Figure 14-4 a frequency-domain diagram of the third frequency-domain data after the light stimulation is shown in FIG. 6. The frequency point marked with an asterisk in the diagram is the frequency point corresponding to the light, and thus it can be determined that the frequency point of the light is increased, i.e., the camera exists in the to-be-detected region.

[0152] Specifically, the light mentioned above can be light with a fixed frequency. Further, in a special case, if the noise signal existing in the surroundings is exactly the same as the signal frequency radiated by the camera after receiving the light stimulation, and the light stimulation is still assumed to be light with a fixed frequency, if there is no camera in the detection area, the noise signal will be received, and it will be mistakenly considered that there is a camera. As another embodiment, in order to overcome the above-mentioned problem, light with a variable frequency can also be used for light stimulation. The variable frequency light represents a light signal with a frequency changing over time. The frequency change of such a light signal can be used to disturb the photoelectric conversion capability of the image sensor of the camera, so as to make it produce a specific electromagnetic response, thereby helping to identify the camera. The variable frequency light stimulation at least includes light with two frequencies. It is assumed that first, light with a low frequency (such as 8 Hz) is irradiated for a period of time, then light with a high frequency (such as 17 Hz) is switched to for a period of time, and then light with a low frequency is switched to, and the cycle is alternately executed.

[0153] Further, when the light stimulation is performed, the bandwidth of the third electromagnetic signal collected can be less than a set value, for example, the bandwidth is 2 KHz. At the same time, the third electromagnetic signal takes a set harmonic as the center frequency. The sampling time can be set to be greater than a sampling threshold value, so as to ensure that the camera with a common frame rate can be detected. The sampling time of the third electromagnetic signal can cover at least two frames of time. For example, the sampling time is set to 0.6 seconds, so that the camera with a frame rate greater than 3.5 Hz can be detected. If the electronic device adds new frequency points in the third frequency domain data after the light stimulation, and the frequencies of these new frequency points are the same as the frequencies of the light (such as 8 Hz or 17 Hz), it is considered that the electronic device is a camera.

[0154] As an embodiment, since most image sensors (CCD and CMOS) are optimized for sensitivity to green light in their spectral response, and the image sensors used by the cameras on the market at present are almost obtained from CCD or CMOS arrays, the camera is usually sensitive to green light. Therefore, when the light stimulation is performed, the electronic device can be stimulated by green light, so that the camera can be more efficiently identified.

[0155] As an embodiment, the frequency of the light should avoid being a multiple of the frame rate (Fp) of the camera, otherwise the newly added frequency will overlap with the frame rate and it is difficult to distinguish. In addition, the frequency of the light should be within a certain interval (for example, between 2-30 Hz), because if the frequency of the light stimulus is too low, the detection time will increase, and if the frequency of the light stimulus is too high, the response of the image sensor will not be obvious enough. In addition, for the above Fm detection scheme, if the frame rate Fp does not need to be detected, the frame rate of the electronic device is not known when the light stimulus is applied, so when the variable frequency light stimulus is used, the frequency should also avoid being a multiple relationship between different light frequencies. For example, the first frequency is 8 Hz, and the second frequency should not be 16 Hz (if the 8 Hz light stimulus is exactly the frame rate of the camera, if the 16 Hz light stimulus is used again, it is also a multiple of the frame rate of the camera, and overlap will occur. If it is not a multiple relationship, although the 8 Hz frequency cannot be identified due to coincidence with the frame rate, if the second frequency is not a multiple of 8 Hz, it can be avoided from overlapping with the frame rate again, so it can be identified. In this way, all light frequencies can be avoided from overlapping with the frame rate, so that the camera cannot be identified, reducing the missed judgment and improving the accuracy of detection.

[0156] Next, in combination with the above embodiments, one specific implementation principle of detecting the camera in combination with the Fm detection scheme, the Fp detection scheme, and the light stimulus scheme will be specifically described. As shown in Figure 15 the following steps are included.

[0157] Step S110 (i.e., step S110 of the above Figure 3 ): Collecting a first electromagnetic signal with a bandwidth less than a first threshold and a frequency of a set harmonic generated by an electronic device in a to-be-detected area.

[0158] Step S210 (i.e., step S210 of the above Figure 3 ): Converting the first electromagnetic signal into first frequency domain data.

[0159] Step S311a: Determine whether there is a frequency point that meets the formula F0±NxFm in the first frequency domain data, if yes, execute step S321; if no, execute step S120.

[0160] The principle of determining whether there is a frequency point that meets the formula F0±NxFm in the first frequency domain data in this step is the same as step S311 in the embodiment shown in the above Figure 3 , which will not be described here. And if it is determined that there is a frequency point that meets the formula F0±NxFm in the first frequency domain data, step S321 is further executed, i.e., further light stimulus is performed to improve the accuracy of detection. If not, step S120 is further executed, i.e., although it is not detected by the Fm detection scheme, the Fp detection scheme can be further used for detection.

[0161] Step S120 (i.e., step S120 in the above Figure 10 : Collecting the second electromagnetic signal with a frequency of a set harmonic generated by the electronic device in the to-be-detected region and with a bandwidth less than a second threshold.

[0162] Step S220 (i.e., step S220 in the above Figure 10 : Converting the second electromagnetic signal into second frequency domain data.

[0163] Step S312a: Determining whether there is a frequency point in the second frequency domain data that meets the formula F0±NxFp, if yes, executing step S321; if no, executing step S110.

[0164] In this step, the principle of determining whether there is a frequency point in the second frequency domain data that meets the formula F0±NxFp is the same as that of step S312 in the above Figure 10 , which will not be repeated here. If there is a frequency point in the second frequency domain data that meets the formula F0±NxFp, step S321 is further executed, that is, light stimulation is also required. If not, it means that there is no camera in the to-be-detected region, and then new data can be collected.

[0165] Step S321: Collecting a third electromagnetic signal generated by the electronic device in the to-be-detected region after receiving light stimulation. The principle of this step can be referred to step S320 in the above Figure 12 .

[0166] Step S500 (i.e., step S500 in the above Figure 12 : If it is determined that the third electromagnetic signal has a characteristic corresponding to the light, it is determined that the to-be-detected region has a camera.

[0167] In this embodiment, the Fm detection scheme is executed first, and then the Fp detection scheme is executed. Since the Fm characteristic of the camera may not be relatively obvious in some scenes, the Fp characteristic can be further used for detection at this time, so that the false negative rate can be reduced. Moreover, light stimulation is finally required to exclude electronic screens and other electronic devices, so that the detection accuracy can be improved.

[0168] It can be understood that in other embodiments, whether to detect Fm first or Fp first can be selected according to actual detection requirements and scene characteristics, so that the most suitable detection method can be selected according to specific scenes and requirements. For example, if the detection speed requirement is high, only the Fm detection scheme combined with the light stimulation scheme can be selected. If it is necessary to further improve the accuracy of the detection result, the Fm detection scheme can be selected first, and then the Fp detection scheme can be selected, so as to meet the needs of different application scenes.

[0169] Figure 16The scheme of detecting Fm first and then detecting Fp is shown, which is different from the above Figure 15 The difference is that when performing step S311a, if it is judged that the first frequency domain data has Fm characteristics (i.e., the first frequency domain data has a frequency point conforming to the formula F0±NxFm), the subsequent Fp detection scheme (i.e., steps S120, S220, S312a) is continued to be performed, and if it is judged that the second frequency domain data has Fp characteristics (i.e., the second frequency domain data has a frequency point conforming to the formula F0±NxFp), the light stimulation (i.e., steps S321, S500) is further performed. This scheme successively adopts the Fm detection scheme, the Fp detection scheme, and the light stimulation scheme, so that the accuracy of detecting the camera can be further improved.

[0170] In an optional embodiment, the above method further comprises: if it is determined that the camera exists in the to-be-detected area, determining the number or the type number of the camera according to the number of the harmonic signals.

[0171] It should be understood that the harmonic signal is, for example, F0 described above.

[0172] For F0: different types of cameras have different F0. Therefore, by using the above camera detection method, it can be determined how many F0 exist in the to-be-detected area, that is, how many types of cameras exist.

[0173] Specifically, when performing step S110 described above, the set harmonic can be determined based on the existing cameras on the market. For example, there are five types of cameras on the market, and the corresponding set harmonics are F01, F02, F03, F04, and F05. First, F01 is used as the current set harmonic to perform the camera detection method of each embodiment described above. If it is finally judged that the camera exists, it means that the camera with the harmonic signal F01 exists. Similarly, F02, F03, F04, and F05 can also be used as set harmonics to perform the camera detection method of each embodiment described above. Finally, it is assumed that after detection with the five set harmonics, it is determined that the camera exists, that is, the number of harmonic signals is five, which means that the type number of the camera in the to-be-detected area is five.

[0174] It can be understood that the type number of the camera can also be determined based on the number of the two parameters Fm and Fp.

[0175] For Fm: Fm is determined by the frame rate Fp and the pixel row Rp and the blanking row Rb of the camera, that is, Fm=Fp×(Rp+Rb). Even if Fp is the same, Fm of different types of cameras can be different, so Fm can be used to distinguish the cameras, and the number of Fm can help to determine the type number of the camera.

[0176] For Fp: different kinds of camera devices can have different frame rates Fp, so the camera devices can also be distinguished by Fp, and the number of Fp can also help determine the number of kinds of camera devices.

[0177] Wherein, as to determining the number of kinds of camera devices by the number of Fm, Fp, the principle is basically the same as the above determination process of F0, which will not be repeated here.

[0178] Further, the embodiment can determine the number of kinds of camera devices according to the number of F0, Fm, Fp. Specifically, the number of kinds of camera devices can be determined according to the maximum value in F0, Fm, Fp. For example:

[0179] Suppose that by the above camera device detection method, F0 has 8 different values, Fm has 10 different values, and Fp has 9 different values, then it can be considered that there are 10 kinds of camera devices.

[0180] It should be noted that if the same kind of camera device also has different F0, Fm, Fp, the number of camera devices can also be identified according to the number of F0, Fm, Fp.

[0181] In summary, the detection method adopted by the embodiment of the application is to detect according to Fm and / or Fp. For the Fm detection scheme, the detection time is about 5ms, and for the Fp detection scheme, the detection time is about 0.2s. After verification, the overall detection time is within 50ms. Secondly, the light stimulation and the Fm detection scheme and the Fp detection scheme can also be parallel processing (the light stimulation can be started as soon as the actual detection starts, that is, even if Fm or Fp has not been detected, the data of the light stimulation can still be received synchronously, in this way, as soon as Fm or Fp is detected, the data of the light stimulation can be used to exclude the interference of the electronic screen, thereby improving the detection efficiency). Among them, the longest residence time of the light stimulation is only about 0.5s, that is, when the user uses the camera device detection device to scan each area, he can completely measure while walking, without deliberately staying in a certain area. For example, for a room of 100 square meters, the detection method adopted by the embodiment of the application can scan the entire room within ten minutes. The detection method in the traditional scheme needs several tens of minutes to several hours to detect a room of the same size, obviously the detection method adopted by the embodiment of the application is more efficient.

[0182] In summary, the camera detection method provided by the embodiments of the present application can achieve the following effects: first, the camera detection method is not limited by whether the camera transmits wireless signals, and as long as the camera is powered on and works normally, the electromagnetic signal of the camera can be detected if the electromagnetic signal meets the characteristics, the actual existing camera can be comprehensively and accurately detected, and the false negative rate is reduced. Second, by analyzing the frequency distribution of the harmonic signal of the crystal oscillator, the camera signal can be more accurately identified, the detection accuracy and reliability are improved, and the false positive rate is reduced. Third, the camera detection method is suitable for all types of cameras, regardless of the transmission method or whether real-time signal transmission is performed, as long as the camera is powered on and works, the harmonic signal can be detected, the detection accuracy, reliability and applicability are significantly improved, and the false negative rate is reduced. Fourth, the harmonic signal of the camera crystal oscillator is an inherent characteristic of the camera when it works, and is not affected by specific scene conditions. Therefore, the camera detection method is suitable for all types of cameras in any scene, the detection accuracy, reliability and applicability are significantly improved, and the false negative rate is reduced.

[0183] In an exemplary embodiment, referring to Figure 17 The embodiments of the present application provide a camera detection device, comprising:

[0184] The collection unit is configured to collect electromagnetic signals generated by electronic devices in a to-be-detected region.

[0185] The determination unit is configured to determine that the to-be-detected region contains a camera if the electromagnetic signals meet the characteristics corresponding to the harmonic signals of the camera.

[0186] The camera detection device further comprises:

[0187] The conversion unit is configured to convert the electromagnetic signals into frequency domain data.

[0188] The determination unit is specifically configured to determine that the to-be-detected region contains a camera if the frequency domain data meet a set frequency distribution rule corresponding to the harmonic signals of the camera.

[0189] The collection unit is specifically configured to collect a first electromagnetic signal with a bandwidth less than a first threshold and generated by an electronic device in a to-be-detected region, the first electromagnetic signal having a frequency of a set harmonic.

[0190] The conversion unit is specifically configured to convert the first electromagnetic signal into first frequency domain data.

[0191] The determination unit is specifically configured to determine that the to-be-detected region contains a camera if it is determined that there is a frequency point meeting the formula F0±N×Fm in the first frequency domain data, where F0 is the set harmonic, N is a natural number, and Fm is the number of pixel rows scanned per second by the camera.

[0192] The determining unit is specifically configured to determine a target peak point, and determine that the camera exists in the to-be-detected region if it is determined according to a frequency difference between the target peak point and peak points located on both sides of the target peak point that there is a frequency point in the first frequency domain data that meets the formula F0±N×Fm.

[0193] The determining unit is specifically configured to take the highest peak point in the first frequency domain data as the target peak point.

[0194] The determining unit is specifically configured to determine that the camera exists in the to-be-detected region if it is determined according to a frequency difference between the target peak point and peak points located on both sides of the target peak point that there is a frequency point in the first frequency domain data that meets the formula F0±N×Fm, and take other peak points in the first frequency domain as new target peak points, and determine whether there is a frequency point in the first frequency domain data that meets the formula F0±N×Fm according to a frequency difference between the new target peak points and peak points located on both sides of the new target peak points.

[0195] The determining unit is specifically configured to take an absolute value of a frequency difference between a first peak point and the target peak point as fm1, wherein the first peak point is a peak point located on a first side of the target peak point and having a minimum absolute value of a frequency difference with the target peak point, and determine that there is a frequency point in the first frequency domain data that meets the formula F0±N×Fm if there is a peak point on a second side of the target peak point and having an absolute value of a frequency difference with the target peak point equal to the fm1, and take the fm1 as the Fm and the target peak point as the F0.

[0196] The determining unit is further configured to take an absolute value of a frequency difference between a second peak point and the target peak point as fm2 if there is no peak point on the second side of the target peak point and having an absolute value of a frequency difference with the target peak point equal to the fm1, wherein the second peak point is located on the first side of the target peak point, and an absolute value of a frequency difference between the second peak point and the target peak point is greater than an absolute value of a frequency difference between the first peak point and the target peak point, and determine that the camera exists in the to-be-detected region if there is a peak point on the second side of the target peak point and having an absolute value of a frequency difference with the target peak point equal to the fm2, and the fm2 is the Fm and the target peak point is the F0.

[0197] The determining unit is specifically configured to: if a peak point with a frequency difference absolute value equal to the fm1 exists between the target peak point and a peak point on the second side of the target peak point, perform step B, wherein step B is to find a peak point with a frequency difference absolute value of 2fm1 on the first side of the target peak point, and step C is to determine that the camera exists in the to-be-detected region if a peak point with a frequency difference absolute value of 2fm1 exists on the second side of the target peak point.

[0198] The collecting unit is specifically configured to collect a second electromagnetic signal with a bandwidth less than a second threshold and a frequency being a set harmonic generated by the electronic device in the to-be-detected region.

[0199] The converting unit is specifically configured to convert the second electromagnetic signal into second frequency domain data.

[0200] The determining unit is specifically configured to determine that the camera exists in the to-be-detected region if a frequency point with a frequency of F0±N×Fp exists in the second frequency domain data. F0 is the set harmonic, N is a natural number, and Fp is a frame rate of the camera.

[0201] The determining unit is specifically configured to collect a third electromagnetic signal generated by the electronic device after accepting light stimulation in the to-be-detected region if the electromagnetic signal satisfies a feature corresponding to a harmonic signal of the camera, and determine that the camera exists in the to-be-detected region if it is determined that the third electromagnetic signal has a feature corresponding to the light.

[0202] The determining unit is specifically configured to determine that the camera exists in the to-be-detected region if it is determined that the amplitude of one or more time points in a time domain curve corresponding to the third electromagnetic signal is greater than a set jitter threshold.

[0203] The converting unit is further configured to convert the third electromagnetic signal into third frequency domain data.

[0204] The determining unit is specifically configured to determine that the camera exists in the to-be-detected region if it is determined that a frequency point with the same frequency as the light frequency exists in the third frequency domain data.

[0205] The determining unit is further configured to determine the number or the type number of the camera according to the number of the harmonic signals if it is determined that the camera exists in the to-be-detected region.

[0206] Further, please refer to Figure 18 An embodiment of the camera detection device in the embodiment of the application includes

[0207] The central processing unit 1801, the memory 1805, the input and output interface 1804, the wired or wireless network interface 1803 and the power supply 1802.

[0208] The memory 1805 is a volatile storage memory or a persistent storage memory.

[0209] The central processing unit 1801 is configured to communicate with the memory 1805 and execute the instruction operation in the memory 1805 to perform the camera detection method in the foregoing embodiments.

[0210] In one exemplary embodiment, the embodiments of the present application further provide a computer readable storage medium including instructions, when the instructions are run on a computer, causing the computer to execute the camera detection method in the foregoing embodiments.

[0211] In one exemplary embodiment, the embodiments of the present application further provide a computer program product including instructions, when the computer program product is run on a computer, causing the computer to execute the camera detection method in the foregoing embodiments.

[0212] It should be understood that, although each step in the flowchart involved in each of the above-described embodiments is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in each of the above-described embodiments can include multiple steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or steps or stages in other steps.

[0213] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0214] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0215] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0216] 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. The integrated unit can be implemented in hardware or as a software functional unit.

[0217] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or 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 application. 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.

Claims

1. An image pickup device detecting method characterized by comprising: The method comprises the following steps: collecting electromagnetic signals generated by electronic devices in a to-be-detected area; if the electromagnetic signals meet the characteristics of the harmonic signals of the camera, it is determined that the to-be-detected area has a camera; the frequency of the harmonic signals is an integer multiple of the frequency of the clock signal in the camera.

2. The method of claim 1, wherein, After the step of collecting electromagnetic signals generated by electronic devices in a to-be-detected area, the method further comprises: converting the electromagnetic signals into frequency domain data; if the electromagnetic signals meet the characteristics of the harmonic signals of the camera, it is determined that the to-be-detected area has a camera, comprising: if the frequency domain data meet the set frequency distribution rule of the harmonic signals of the camera, it is determined that the to-be-detected area has a camera.

3. The method of claim 2, wherein, The step of collecting electromagnetic signals generated by electronic devices in a to-be-detected area comprises: collecting a first electromagnetic signal with a bandwidth less than a first threshold and generated by an electronic device in the to-be-detected area, the frequency of the first electromagnetic signal being a set harmonic; The step of converting the electromagnetic signals into frequency domain data comprises: converting the first electromagnetic signal into first frequency domain data; The step of determining that the to-be-detected area has a camera if the frequency domain data meet the set frequency distribution rule of the harmonic signals of the camera comprises: if it is determined that there are frequency points meeting the formula F0±N×Fm in the first frequency domain data, it is determined that the to-be-detected area has a camera; wherein F0 is the set harmonic; N is greater than or equal to 1; Fm is the total number of lines scanned per second by the camera.

4. The method of claim 3, wherein, The step of determining that the to-be-detected area has a camera if it is determined that there are frequency points meeting the formula F0±N×Fm in the first frequency domain data comprises: determining a target peak point; if it is determined that there are frequency points meeting the formula F0±N×Fm in the first frequency domain data according to the frequency difference between the target peak point and the peak points located on both sides of the target peak point, it is determined that the to-be-detected area has a camera.

5. The method of claim 4, wherein, The step of determining a target peak point comprises: taking the highest peak point in the first frequency domain data as the target peak point; The step of determining that the to-be-detected area has a camera if it is determined that there are frequency points meeting the formula F0±N×Fm in the first frequency domain data according to the frequency difference between the target peak point and the peak points located on both sides of the target peak point comprises: if it is determined that there are frequency points meeting the formula F0±N×Fm in the first frequency domain data according to the frequency difference between the target peak point and the peak points located on both sides of the target peak point, it is determined that the to-be-detected area has a camera; if it is unable to determine that there are frequency points meeting the formula F0±N×Fm in the first frequency domain data according to the frequency difference between the target peak point and the peak points located on both sides of the target peak point, other peak points in the first frequency domain data are taken as new target peak points; whether there are frequency points meeting the formula F0±N×Fm in the first frequency domain data is determined according to the frequency difference between the new target peak points and the peak points located on both sides of the new target peak points.

6. The method of claim 5, wherein, The method further comprises: If the absolute value of the frequency difference between the target peak point and the peak point on the second side of the target peak point is equal to the fm1, it is determined that the to-be-detected region has a camera device; and the fm1 is the Fm, and the target peak point is the F0. After recording the absolute value of the frequency difference between the first peak point and the target peak point as fm1, the method further comprises:

7. The method of claim 6, wherein, If there is no peak point on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is equal to the fm1, the absolute value of the frequency difference between the second peak point and the target peak point is recorded as fm2; the second peak point is located on the first side of the target peak point, and the absolute value of the frequency difference between the second peak point and the target peak point is greater than the absolute value of the frequency difference between the first peak point and the target peak point; If there is a peak point on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is equal to the fm2, it is determined that the to-be-detected region has a camera device; and the fm2 is the Fm, and the target peak point is the F0. The method further comprises:

8. The method of claim 6, wherein, If there is a peak point on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is equal to the fm1, it is determined that the to-be-detected region has a camera device; and the fm1 is the Fm, and the target peak point is the F0. The method further comprises: Step A: If there is a peak point on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is equal to the fm1, execute step B; Step B: Find a peak point on the first side of the target peak point, the absolute value of the frequency difference between which and the target peak point is 2fm1; 9. The method of claim 2, wherein, Step C: If there is a peak point on the second side of the target peak point, the absolute value of the frequency difference between which and the target peak point is 2fm1, it is determined that the to-be-detected region has a camera device. The method further comprises: Collecting a second electromagnetic signal generated by an electronic device in the to-be-detected region, the second electromagnetic signal having a bandwidth less than a second threshold and a frequency being a set harmonic; The method further comprises: Converting the second electromagnetic signal into second frequency domain data; If the frequency domain data satisfies a set frequency distribution rule corresponding to a harmonic signal of a camera device, it is determined that the to-be-detected region has a camera device. If there is a frequency point in the second frequency domain data that meets the formula F0±N×Fp, it is determined that the camera exists in the to-be-detected region; wherein F0 is the set harmonic; N is greater than or equal to 1; and Fp is the frame rate of the camera.

10. The method according to any one of claims 1 to 9, characterized in that, If the electromagnetic signal meets the characteristics corresponding to the harmonic signal of the camera, the third electromagnetic signal generated by the electronic device in the to-be-detected region after receiving the light stimulation is collected. If it is determined that the third electromagnetic signal has characteristics corresponding to the light, it is determined that the camera exists in the to-be-detected region. If it is determined that the third electromagnetic signal has characteristics corresponding to the light, it is determined that the camera exists in the to-be-detected region.

11. The method of claim 10, wherein, If it is determined that the third electromagnetic signal has characteristics corresponding to the light, it is determined that the camera exists in the to-be-detected region. If it is determined that the third electromagnetic signal has characteristics corresponding to the light, it is determined that the camera exists in the to-be-detected region.

12. The method of claim 10, wherein, If it is determined that the third electromagnetic signal has characteristics corresponding to the light, it is determined that the camera exists in the to-be-detected region. The light is a variable frequency light, and the different frequencies of the variable frequency light do not have a multiple relationship. The method further comprises: If it is determined that the camera exists in the to-be-detected region, the number or the type of the camera is determined according to the number of the harmonic signals.

13. The method of claim 10, wherein, The method further comprises:

14. The method according to any one of claims 1-9, characterized in that, The acquisition unit is configured to collect the electromagnetic signal generated by the electronic device in the to-be-detected region. The determination unit is configured to determine that the camera exists in the to-be-detected region if the electromagnetic signal meets the characteristics corresponding to the harmonic signal of the camera; the frequency of the harmonic signal is an integer multiple of the frequency of the clock signal in the camera.

15. An imaging device detection apparatus, comprising: The method further comprises: The central processing unit and the memory; The memory is a transitory memory or a persistent memory; 16. An imaging device detection apparatus, characterized by comprising: The central processing unit is configured to communicate with the memory and execute the instruction operation in the memory to perform the method in any one of claims 1 to 14. The computer readable storage medium comprises instructions, when the instructions are executed on the computer, the computer executes the method in any one of claims 1 to 14. When the computer program product is executed on the computer, the computer executes the method in any one of claims 1 to 14. ​ 17. A computer readable storage medium characterized by: ​ 18. A computer program product comprising instructions, characterized in that, ​

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