Method, device and apparatus for extracting speckle noise spectrum in off-track area

Abstract

The application provides a method, device and equipment for extracting a non-track area spot noise spectrum, which comprises the following steps: in a sea state of a single sea wave component, determining a sea surface condition range when a sea wave energy density spectrum density is less than a preset density and a wave direction angle range when a value of a direction function is less than a preset function value, wherein the single sea wave component comprises pure wind wave or pure swell, the sea surface condition range comprises a sea surface wind speed range and a sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine a distribution of sea wave energy; and under the limitation of the sea surface condition range and the wave direction angle range, extracting a sea wave fluctuation spectrum of a non-track area to obtain a non-track area spot noise spectrum. Through the method, the accuracy of extracting the non-track area spot noise spectrum can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of extracting speckle noise spectrum, in particular, to a method, device and equipment for extracting speckle noise spectrum in non-tracked area. BACKGROUND

[0002] At present, many dynamic processes of the ocean need to accurately grasp the information of the sea wave. The sea wave has randomness and can be regarded as a random process. At present, the most effective way to describe the sea wave is the sea wave directional spectrum, which is defined as the distribution of sea wave energy relative to frequency and direction. The sea wave directional spectrum not only represents the distribution of sea wave energy in each direction, but also can be used to calculate various sea wave parameters, such as effective wave height, main wave direction, etc. Therefore, obtaining accurate sea wave directional spectrum is one of the key tasks of sea wave research. The existing experience method extracts speckle noise spectrum samples in non-tracked area by using the least variance method, that is, finding the variance minimum of the modulation signal in the 0-360° azimuth angle range. The wave spectrum corresponding to the azimuth angle is equivalent to the speckle noise spectrum.

[0003] The above method has great limitations. When the effective wave height and wind speed on the sea surface are large, the energy density spectrum density of the two-dimensional sea wave spectrum is large, and the modulation signal with the minimum variance will not be located near the side wave direction. At this time, the extracted modulation signal will also contain the sea wave modulation signal, and the accuracy of extracting the speckle noise spectrum in the non-tracked area cannot be improved.

[0004] Therefore, how to improve the accuracy of extracting the speckle noise spectrum in the non-tracked area is a technical problem to be solved. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a method for extracting speckle noise spectrum in non-tracked area. The technical scheme of the embodiments of the present application can achieve the effect of improving the accuracy of extracting the speckle noise spectrum in non-tracked area.

[0006] In a first aspect, the embodiments of the present application provide a method for extracting speckle noise spectrum in non-tracked area, comprising: determining, in a sea condition of a single sea wave component, a sea surface condition range when sea wave energy density spectrum density is less than a preset density and a wave direction angle range when the value of a direction function is less than a preset function value, wherein the single sea wave component includes pure wind wave or pure surge wave, the sea surface condition range includes a sea surface wind speed range and a sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine the distribution of sea wave energy; and extracting, under the limitation of the sea surface condition range and the wave direction angle range, sea wave fluctuation spectrum in non-tracked area to obtain speckle noise spectrum in non-tracked area.

[0007] In the above embodiment, when the sea wave component is single, the sea surface condition range and the wave direction angle of the non-track area are limited, that is, when the sea surface condition range and the wave direction angle of the non-track area meet the requirements, the sea wave fluctuation spectrum of the non-track area is extracted, so that the sea wave fluctuation spectrum extracted at the minimum sea wave energy can be doped with little sea wave modulation spectrum, the extracted sea wave fluctuation spectrum can be regarded as the non-track area speckle noise spectrum extracted by the application, and the accuracy of the extracted non-track area speckle noise spectrum can be improved.

[0008] In some embodiments, in a sea state with a single sea wave component, the sea surface condition range when the sea wave energy density spectrum density is less than a preset density and the wave direction angle range when the value of the direction function is less than a preset function value are determined, including:

[0009] In a sea state with a single sea wave component, the sea surface wind speed when the sea wave fluctuation spectrum extracted by the wave spectrum instrument is affected by the nonlinear modulation less than a preset condition, that is, the minimum value of the sea surface wind speed range.

[0010] In the above embodiment, when the extracted sea wave fluctuation spectrum is affected by the nonlinear modulation and meets the preset condition, the sea surface wind speed at this time can be obtained, that is, the sea surface wind speed at this time can be regarded as the minimum value of the sea surface wind speed range, and the effect of limiting the minimum value of the sea surface wind speed range is achieved.

[0011] In some embodiments, in a sea state with a single sea wave component, the sea surface condition range when the sea wave energy density spectrum density is less than a preset density and the wave direction angle range when the value of the direction function is less than a preset function value are determined, including:

[0012] In a sea state with a single sea wave component, the sea surface condition range when the sea wave energy density spectrum density is less than a preset density is determined.

[0013] The wave direction angle range when the value of the direction function is less than a preset function value is determined.

[0014] In the above embodiment, in a sea state with a single sea wave component, the sea surface condition range and the wave direction angle range can be limited respectively to obtain the sea surface condition range limitation and the wave direction angle range limitation when the non-track area speckle noise spectrum is accurately extracted.

[0015] In some embodiments, the sea surface condition range when the sea wave energy density spectrum density is less than a preset density is determined, including:

[0016] In a pure wind wave sea state, the sea surface wind speed when the sea wave energy density spectrum density is less than a preset density is determined, and in a pure swell sea state, the sea wave effective wave height when the sea wave energy density spectrum density is less than a preset density is determined, that is, the maximum value of the sea surface wind speed range and the maximum value of the sea wave effective wave height range.

[0017] In the above embodiment, the sea surface wind speed and the effective wave height in the sea surface condition range can be limited, so as to improve the accuracy of extracting the speckle noise spectrum in the non-track area under the limitation.

[0018] In some embodiments, the range of the wave direction angle when the value of the directional function is less than the preset function value is determined, including:

[0019] The range of the wave direction angle is determined according to the wave detection azimuth interval value of the wave spectrum instrument and the wave direction angle when the value of the directional function is less than the preset function value.

[0020] In the above embodiment, the range of the wave direction angle can be limited by the above method, so as to improve the accuracy of extracting the speckle noise spectrum in the non-track area under the limitation.

[0021] In some embodiments, in the sea state of a single wave component, the sea surface condition range when the wave energy density spectrum density is less than the preset density and the range of the wave direction angle when the value of the directional function is less than the preset function value are determined, including:

[0022] In the sea state of pure wind wave, the minimum value of the sea surface wind speed range when the wave energy density spectrum density is less than the preset density is 5 m / s, and the maximum value is 10 m / s;

[0023] In the sea state of pure swell, the minimum value of the effective wave height range when the wave energy density spectrum density is less than the preset density is 0, and the maximum value is 1 m;

[0024] The difference between the wave direction angle when the directional function is the minimum value and the wave detection azimuth interval value of the wave spectrum instrument and the sum of the wave direction angle when the directional function is the minimum value and the wave detection azimuth interval value of the wave spectrum instrument are determined, and the minimum value of the range of the wave direction angle is 82.5°, and the maximum value is 97.5°.

[0025] In the above embodiment, according to the actual operation, the sea surface condition range, the sea surface wind speed, the effective wave height and the range of the wave direction angle are accurately calculated, and the accuracy of extracting the speckle noise spectrum in the non-track area can be improved under the limitation of the above conditions.

[0026] In some embodiments, under the limitation of the sea surface condition range and the range of the wave direction angle, the wave fluctuation spectrum in the non-track area is extracted, and the speckle noise spectrum in the non-track area is obtained, including:

[0027] The wave fluctuation spectrum sample under the limitation of the sea surface condition range and the range of the wave direction angle is selected;

[0028] The mean value of the wave fluctuation spectrum sample is calculated to obtain the speckle noise spectrum in the non-track area.

[0029] In the above embodiments, the non-track area speckle noise spectrum obtained by calculating the sea surface condition range and the wave direction angle range under the limitation of the sea wave fluctuation spectrum sample mean value improves the accuracy of extracting the non-track area speckle noise spectrum.

[0030] In a second aspect, the embodiments of the present application provide a device for extracting a non-track area speckle noise spectrum, comprising:

[0031] The determining module is configured to determine, in a sea state of a single sea wave component, a sea surface condition range when a sea wave energy density spectrum density is less than a preset density and a wave direction angle range when a value of a direction function is less than a preset function value, wherein the single sea wave component includes pure wind waves or pure swell, the sea surface condition range includes a sea surface wind speed range and a sea wave significant wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine the distribution of sea wave energy.

[0032] The extracting module is configured to extract, under the limitation of the sea surface condition range and the wave direction angle range, sea wave fluctuation spectra in a non-track area to obtain a non-track area speckle noise spectrum.

[0033] Optionally, the determining module is specifically configured to:

[0034] In the sea state of the single sea wave component, the sea surface wind speed when the sea wave fluctuation spectrum extracted by the wave spectrum instrument is affected by the nonlinear modulation less than a preset condition, that is, the minimum value of the sea surface wind speed range.

[0035] Optionally, the determining module is specifically configured to:

[0036] In the sea state of the single sea wave component, the sea surface condition range when the sea wave energy density spectrum density is less than a preset density.

[0037] The wave direction angle range when the value of the direction function is less than a preset function value.

[0038] Optionally, the determining module is specifically configured to:

[0039] In the pure wind wave sea state, the sea surface wind speed when the sea wave energy density spectrum density is less than a preset density; in the pure swell sea state, the sea wave significant wave height when the sea wave energy density spectrum density is less than a preset density, that is, the maximum value of the sea surface wind speed range and the maximum value of the sea wave significant wave height range.

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

[0041] According to the sea wave detection azimuth angle interval value of the wave spectrum instrument and the wave direction angle when the value of the direction function is less than a preset function value, the wave direction angle range is determined.

[0042] Optionally, the determining module is specifically configured to:

[0043] The minimum value of the sea surface wind speed range when the sea wave energy density spectrum density is less than the preset density is 5 m / s, and the maximum value is 10 m / s;

[0044] The minimum value of the sea wave effective wave height range when the sea wave energy density spectrum density is less than the preset density is 0, and the maximum value is 1 m;

[0045] The difference between the wave direction angle and the sea wave detection azimuth interval value of the wave spectrum instrument when the directional function is the minimum value, and the sum of the wave direction angle and the sea wave detection azimuth interval value of the wave spectrum instrument when the directional function is the minimum value, then the minimum value of the wave direction angle range is 82.5°, and the maximum value is 97.5°.

[0046] Optionally, the extraction module is specifically configured to:

[0047] The sea wave fluctuation spectrum sample under the restriction of the sea surface condition range and the wave direction angle range is selected;

[0048] The mean value of the sea wave fluctuation spectrum sample is calculated to obtain the non-in-track area speckle noise spectrum.

[0049] In a third aspect, an electronic device is provided, including a processor and a memory, the memory storing computer readable instructions that, when executed by the processor, perform the steps of the method of the first aspect.

[0050] In a fourth aspect, a readable storage medium is provided, storing a computer program that, when executed by a processor, performs the steps of the method of the first aspect.

[0051] Other features and advantages of the present application will be described in the following description, and some will become apparent from the description, or will be understood through implementation of the embodiments of the present application. The purpose and other advantages of the present application can be achieved and obtained through the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments of the present application. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0053] Figure 1 A flowchart of a method for extracting a non-in-track area speckle noise spectrum provided by the embodiments of the present application;

[0054] Figure 2A flow chart of an embodiment of a method for extracting a speckle noise spectrum of a non-rail-following region is provided.

[0055] Figure 3 A schematic block diagram of an embodiment of a device for extracting a speckle noise spectrum of a non-rail-following region is provided.

[0056] Figure 4 A structural schematic diagram of an embodiment of a device for extracting a speckle noise spectrum of a non-rail-following region is provided. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0058] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Meanwhile, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0059] First, some terms involved in the embodiments of the present application are explained in order to facilitate understanding by those skilled in the art.

[0060] Terminal device: can be a mobile terminal, a fixed terminal or a portable terminal, for example, a mobile phone, a station, a unit, a device, a multimedia computer, a multimedia tablet, an Internet node, a communicator, a desktop computer, a laptop computer, a notebook computer, a netbook computer, a tablet computer, a personal communication system device, a personal navigation device, a personal digital assistant, an audio / video player, a digital camera / camcorder, a positioning device, a television receiver, a radio broadcast receiver, an electronic book device, a game device, or any combination thereof, including accessories and peripherals of these devices or any combination thereof. It is also foreseeable that the terminal device can support any type of interface for the user (such as wearable devices) and the like.

[0061] Server: can be a stand-alone physical server, can also be a server cluster or distributed system composed of multiple physical servers, can also be a cloud server providing cloud service, cloud database, cloud computing, cloud function, cloud storage, network service, cloud communication, middleware service, domain name service, security service and basic cloud computing services such as big data and artificial intelligence platform.

[0062] Ocean wave spectrum: (ocean wave spectrum) describes the spectrum of energy distribution within the sea wave relative to frequency and direction. Also known as ocean energy spectrum. It is an important concept for studying sea waves. The sea wave spectrum not only shows the internal composition of the sea wave, but also gives the external characteristics of the sea wave.

[0063] Nonlinear modulation: refers to the modulation process in which the modulated parameter in the modulated wave changes nonlinearly with the modulation signal.

[0064] Direction function: usually take the direction spectrum as S(ω,θ)=S(ω)*G(ω,θ), where S(ω) is the frequency spectrum, G(ω,θ) is a function that reflects the energy distribution relative to the direction, and θ is the angle between the main direction of the sea wave (usually the average wind direction) and the wave direction of the wave. G(ω,θ) must be obtained by observation, of which the simplest form is cos. Usually take 2-4, the larger, the more energy is concentrated near the main wave direction. For shallow water waves, it is relatively large.

[0065] Spectrometer: SWIM (Surface Wave Investigation and Monitoring) is the world's first satellite-borne microwave radar for sea wave spectrum detection. SWIM irradiates the sea surface with 6 beams at 0°, 2°, 4°, 6°, 8° and 10° in turn, and the antenna rotates in the range of 0-360°. The adjacent azimuth angles of the same beam are separated by 220ms, and the azimuth angle interval is 7.5°. The two signals of adjacent azimuth angles are incoherent, and the speckle noise spectrum cannot be accurately measured and removed using cross-spectrum method.

[0066] Signal modulation: is the process or method of changing some characteristics of a waveform according to another waveform or signal.

[0067] The present application is applied to the scene of extracting speckle noise spectrum, and the specific scene is to extract the sea wave spectrum in the non-in-track area under the condition of a certain sea surface condition range and wave direction angle limit, and obtain the speckle noise spectrum in the non-in-track area.

[0068] Currently, many dynamic processes of the ocean need to accurately grasp the information of the sea wave. The sea wave has randomness and can be regarded as a random process. At present, the most effective way to describe the sea wave is the sea wave directional spectrum, which is defined as the distribution of sea wave energy relative to frequency and direction. The sea wave directional spectrum not only represents the distribution of sea wave energy in each direction, but also can be used to calculate various sea wave parameters, such as effective wave height, principal wave direction, etc. Therefore, obtaining accurate sea wave directional spectrum is one of the key tasks of sea wave research. The existing experience method uses the minimum variance method to extract the speckle noise spectrum sample in the non-in-orbit area. By searching for the azimuth angle with the minimum variance of the modulation signal in the 0-360° azimuth angle range, the wave spectrum corresponding to the azimuth angle is equivalent to the speckle noise spectrum. The principle of the minimum variance method for extracting the speckle noise spectrum in the non-in-orbit area is that the variance of the modulation signal can reflect the size of the sea wave spectrum, that is, the size of the sea wave signal. It is known that the sea wave signal in the along-waves direction is the largest, and the sea wave signal in the side-waves direction is almost zero, that is, the sea wave modulation spectrum can be ignored, and the sea wave spectrum is determined as the speckle noise spectrum at this time. The above method has great limitations. When the effective wave height and wind speed of the sea surface are large, the energy density spectrum density of the two-dimensional sea wave spectrum is large, and the modulation signal with the minimum variance will not be located near the side-waves direction. At this time, the extracted modulation signal will also contain the sea wave modulation signal, and the accuracy of extracting the speckle noise spectrum in the non-in-orbit area cannot be improved.

[0069] Therefore, the present application determines the sea surface condition range when the sea wave energy density spectrum density is less than the preset density and the wave direction angle range when the value of the direction function is less than the preset function value under the sea condition of a single sea wave component, wherein the single sea wave component includes pure wind wave or pure surge wave, the sea surface condition range includes the sea surface wind speed range and the sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine the distribution of sea wave energy. Under the limitation of the sea surface condition range and the wave direction angle range, the sea wave fluctuation spectrum in the non-in-orbit area is extracted to obtain the speckle noise spectrum in the non-in-orbit area. By limiting the sea surface condition range and the wave direction angle in the non-in-orbit area, that is, by extracting the sea wave fluctuation spectrum in the non-in-orbit area when the sea surface condition range and the wave direction angle in the non-in-orbit area meet the requirements, it is ensured that the extracted sea wave fluctuation spectrum contains very little sea wave modulation spectrum when the sea wave energy is the smallest. The extracted sea wave fluctuation spectrum can be regarded as the speckle noise spectrum extracted by the present application, and the accuracy of extracting the speckle noise spectrum in the non-in-orbit area can be improved.

[0070] In the embodiments of the present application, the execution subject can be a speckle noise spectrum extraction device in a speckle noise spectrum extraction system in the non-in-orbit area. In actual applications, the speckle noise spectrum extraction device in the non-in-orbit area can be a satellite-borne spectrometer, a terminal device, a server, and other electronic devices, which are not limited herein.

[0071] The following will be described in combination with Figure 1The method for extracting the non-track region speckle noise spectrum of the embodiment of the present application is described in detail.

[0072] Please refer to Figure 1 , Figure 1 The flow chart of the method for extracting the non-track region speckle noise spectrum provided by the embodiment of the present application is shown in Figure 1 The method for extracting the non-track region speckle noise spectrum includes the following steps.

[0073] Step 110: In the sea state of a single sea wave component, determining the sea surface condition range when the sea wave energy density spectrum density is less than a preset density and the wave direction angle range when the value of the direction function is less than a preset function value.

[0074] The single sea wave component includes pure wind wave or pure swell, the sea surface condition range includes the sea surface wind speed range and the sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine the distribution of sea wave energy. The sea wave energy density spectrum is used to represent the distribution of the internal energy of the sea wave relative to the frequency and direction. The sea wave energy density spectrum density represents the density of the sea wave energy in the sea wave energy density spectrum. The product of the sea wave energy density spectrum density and the value of the direction function can be considered as the value of the sea wave energy, and the direction function can be a function used to represent the direction of the sea wave. The actual direction function can be directly obtained from the system or manually defined. When the sea wave energy reaches the minimum value, the sea wave energy density spectrum density and the value of the direction function at this time can be taken as the preset density and the preset function value.

[0075] In some embodiments of the present application, in the sea state of a single sea wave component, determining the sea surface condition range when the sea wave energy density spectrum density is less than a preset density and the wave direction angle range when the value of the direction function is less than a preset function value includes: in the sea state of a single sea wave component, determining the sea surface wind speed when the sea wave fluctuation spectrum extracted by the wave spectrum instrument is affected by the non-linear modulation less than a preset condition, i.e., the minimum value of the sea surface wind speed range.

[0076] In the above process, when the extracted sea wave fluctuation spectrum is affected by the non-linear modulation and meets the preset condition, the sea surface wind speed at this time can be obtained, i.e., the sea surface wind speed at this time can be taken as the minimum value of the sea surface wind speed range, thereby achieving the effect of limiting the minimum value of the sea surface wind speed range.

[0077] The preset condition can be the degree of non-linear modulation, and the specific degree can be set according to requirements, for example, the curvature of the non-linear change when the non-linear modulation occurs can be set.

[0078] In some embodiments of the present application, in a sea state of a single sea wave component, the sea surface condition range when the sea wave energy density spectrum density is less than a preset density and the wave direction angle range when the value of the direction function is less than a preset function value are determined, comprising: in a sea state of a single sea wave component, determining the sea surface condition range when the sea wave energy density spectrum density is less than a preset density; determining the wave direction angle range when the value of the direction function is less than a preset function value.

[0079] In the above process, in a sea state of a single sea wave component, the sea surface condition range and the wave direction angle range can be limited respectively to obtain the sea surface condition range limit and the wave direction angle range limit when the non-track region speckle noise spectrum is accurately extracted.

[0080] In some embodiments of the present application, the sea surface condition range when the sea wave energy density spectrum density is less than a preset density is determined, comprising: in a pure wind wave sea state, determining the sea surface wind speed when the sea wave energy density spectrum density is less than a preset density; in a pure swell sea state, determining the sea wave significant wave height when the sea wave energy density spectrum density is less than a preset density, that is, the maximum value of the sea surface wind speed range and the maximum value of the sea wave significant wave height range.

[0081] In the above process, the sea surface wind speed and the sea wave significant wave height in the sea surface condition range can be limited to improve the accuracy of extracting the non-track region speckle noise spectrum under the limited condition.

[0082] Wherein, the sea wave significant wave height and the sea wave spectrum have the following relationship:

[0083]

[0084] Wherein, H s represents the sea wave significant wave height, F(K, φ) represents the sea wave spectrum, k represents the sea wave number, and φ represents the observation azimuth angle.

[0085] In some embodiments of the present application, the wave direction angle range when the value of the direction function is less than a preset function value is determined, comprising: determining the wave direction angle range according to the sea wave detection azimuth angle interval value of the wave spectrum instrument and the wave direction angle when the value of the direction function is less than a preset function value.

[0086] In the above process, the wave direction angle range can be limited by the above method to improve the accuracy of extracting the non-track region speckle noise spectrum under the limited condition.

[0087] Wherein, the sea wave detection azimuth angle represents the angle between the ground projection of the wave spectrum instrument emission beam and the flight direction.

[0088] In some embodiments of the present application, in the sea state of a single sea wave component, when the sea surface condition range in which the sea wave energy density spectrum density is less than the preset density and the wave direction angle range in which the value of the directional function is less than the preset function value are determined, the minimum value of the sea surface wind speed range in which the sea wave energy density spectrum density is less than the preset density is 5 m / s, and the maximum value is 10 m / s; the minimum value of the sea wave significant wave height range in which the sea wave energy density spectrum density is less than the preset density is 0, and the maximum value is 1 m; the difference between the wave direction angle and the wave detection azimuth interval value of the wave spectrum instrument when the directional function is the minimum value, and the sum of the wave direction angle and the wave detection azimuth interval value of the wave spectrum instrument when the directional function is the minimum value, then the minimum value of the wave direction angle range is 82.5°, and the maximum value is 97.5°.

[0089] In the above process, according to the actual operation, the present application accurately calculates the range of the sea surface wind speed and the sea wave significant wave height and the wave direction angle in the sea surface condition range, and under the limitation of the above conditions, the accuracy of extracting the spot noise spectrum in the non-in-track area can be improved.

[0090] Wherein, the sea surface wind speed is at least greater than 5 m / s to make the wave spectrum detected by the wave spectrum instrument less affected by nonlinear modulation, which can meet the preset condition. For pure swell sea conditions, the energy density spectrum decreases with the decrease of the sea wave significant wave height, so under the limitation of the preset density, the sea wave significant wave height can be determined to be less than 1 m; for pure wind wave sea conditions, the energy density spectrum decreases with the decrease of the wind speed, so under the limitation of the preset density, the sea surface wind speed can be determined to be less than 10 m / s, and for the case of a single sea wave, the relative wave direction angle is at the direction of 90°, and the value of the directional function is the minimum, at this time, considering that the SWIM wave spectrum detection azimuth interval is 7.5°, the relative wave direction angle is determined to be in the range of 82.5°-97.5°.

[0091] Step 120: under the limitation of the sea surface condition range and the wave direction angle range, extracting the sea wave fluctuation spectrum in the non-in-track area to obtain the spot noise spectrum in the non-in-track area.

[0092] Wherein, the in-track direction represents the satellite flight direction, accordingly, the in-track area can represent an area within a certain range near the in-track direction, which can be set according to requirements, or can be determined according to the standards in the field, and the other area can be represented as the non-in-track area, the division between the two is whether the spot noise spectrum changes with the sea surface condition and the wave number, when the spot noise spectrum does not change with the sea surface condition and the wave number, the observation area at this time is used as the division basis. The sea wave fluctuation spectrum includes the spot noise spectrum and the sea wave modulation spectrum, when the sea wave modulation spectrum component is reduced to a very small amount or even ignored under the limitation of the sea surface condition range and the wave direction angle range in the present application, the accuracy of the spot noise spectrum in the non-in-track area can be improved.

[0093] In some embodiments of the present application, the sea wave fluctuation spectrum in the non-track area is extracted under the restriction of the sea surface condition range and the wave direction angle range, and a non-track area speckle noise spectrum is obtained, including: selecting sea wave fluctuation spectrum samples under the restriction of the sea surface condition range and the wave direction angle range; and calculating the mean value of the sea wave fluctuation spectrum samples to obtain the non-track area speckle noise spectrum.

[0094] In the above embodiments, the non-track area speckle noise spectrum obtained by calculating the mean value of the sea wave fluctuation spectrum samples under the restriction of the sea surface condition range and the wave direction angle range improves the accuracy of extracting the non-track area speckle noise spectrum.

[0095] In one embodiment, after the sea wave fluctuation spectrum in the non-track area is extracted under the restriction of the sea surface condition range and the wave direction angle range to obtain the non-track area speckle noise spectrum, the process further includes: rotating the antenna of the wave spectrum instrument in a 0-360° (one revolution) azimuth angle range to find the azimuth angle at which the variance of the modulation signal is the smallest, determining the second sea wave fluctuation spectrum corresponding to the azimuth angle, i.e., the second non-track area speckle noise spectrum; determining the sea wave modulation spectrum in the sea wave fluctuation spectrum and the second sea wave modulation spectrum in the second sea wave fluctuation spectrum, and if the sea wave modulation spectrum is less than or equal to the second sea wave modulation spectrum, taking the sea wave modulation spectrum as the non-track area speckle noise spectrum, and if the sea wave modulation spectrum is greater than the second sea wave modulation spectrum, taking the second sea wave modulation spectrum as the non-track area speckle noise spectrum.

[0096] In the above process, the final speckle noise spectrum can be determined by combining the two methods of determining the non-track area speckle noise spectrum, which can exclude the sea wave modulation spectrum as much as possible to improve the accuracy of extracting the speckle noise spectrum.

[0097] In the above Figure 1 In the above process, the sea surface condition range and the wave direction angle range are determined when the sea wave energy density spectrum density is less than a preset density and the value of the direction function is less than a preset function value under the sea condition of a single sea wave component, wherein the single sea wave component includes pure wind wave or pure swell wave, the sea surface condition range includes the sea surface wind speed range and the sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine the distribution of sea wave energy. The sea wave fluctuation spectrum in the non-track area is extracted under the restriction of the sea surface condition range and the wave direction angle range to obtain the non-track area speckle noise spectrum. The sea surface condition range and the wave direction angle in the non-track area are restricted, i.e., the sea wave fluctuation spectrum in the non-track area is extracted when the sea surface condition range and the wave direction angle in the non-track area meet the requirements, so that the sea wave fluctuation spectrum extracted at the minimum sea wave energy is doped with very little sea wave modulation spectrum, the extracted sea wave fluctuation spectrum can be taken as the non-track area speckle noise spectrum extracted by the present application, and the accuracy of extracting the non-track area speckle noise spectrum can be improved.

[0098] The following will be described in combination withFigure 2 The method for extracting the speckle noise spectrum of the non-track area according to the embodiment of the present application is described in detail.

[0099] Please refer to Figure 2 , Figure 2 The flow chart of the method for extracting the speckle noise spectrum of the non-track area according to the embodiment of the present application is shown in Figure 2 The method for extracting the speckle noise spectrum of the non-track area according to the embodiment of the present application includes:

[0100] Step 210: determining the preset sea surface wind speed, the sea wave effective wave height and the wave direction angle.

[0101] Specifically, in the sea state of single sea wave component, the sea surface wind speed range when the sea wave energy density spectrum density is less than the preset density, the sea wave effective wave height range and the wave direction angle range when the value of the direction function is less than the preset function value are determined. That is, the minimum value of the sea surface wind speed range when the sea wave energy density spectrum density is less than the preset density is 5 m / s, and the maximum value is 10 m / s; the minimum value of the sea wave effective wave height range when the sea wave energy density spectrum density is less than the preset density is 0, and the maximum value is 1 m; the difference between the wave direction angle when the direction function is the minimum value and the sea wave detection azimuth interval value of the wave spectrum instrument and the sum of the wave direction angle when the direction function is the minimum value and the sea wave detection azimuth interval value of the wave spectrum instrument, then the minimum value of the wave direction angle range is 82.5°, and the maximum value is 97.5°.

[0102] Step 220: under the condition of the preset sea surface wind speed, the sea wave effective wave height and the wave direction angle, extracting the sea wave fluctuation spectrum of the non-track area to obtain the speckle noise spectrum of the non-track area.

[0103] Specifically, the extracted sea wave fluctuation spectrum of the non-track area is taken as the speckle noise spectrum of the non-track area.

[0104] In addition, Figure 2 The specific method and steps shown in Figure 1 will not be described here in detail.

[0105] The method for extracting the speckle noise spectrum of the non-track area is described above, Figures 1-2 and the device for extracting the speckle noise spectrum of the non-track area is described below in combination with Figures 3-4 .

[0106] Please refer to Figure 3 The schematic block diagram of the device 300 for extracting the speckle noise spectrum of the non-track area according to the embodiment of the present application is shown in the figure, which can be a module, a program segment or code on an electronic device. The device 300 corresponds to the above Figure 1 method embodiment and can execute Figure 1The method embodiment relates to various steps, and the specific functions of the device 300 can be referred to the following description, and the detailed description is appropriately omitted here to avoid repetition.

[0107] Optionally, the device 300 comprises:

[0108] The determining module 310 is configured to determine, in a sea state of a single sea wave component, a sea surface condition range and a wave direction angle range when a sea wave energy density spectrum density is less than a preset density and a value of a direction function is less than a preset function value, wherein the single sea wave component comprises pure wind wave or pure swell, the sea surface condition range comprises a sea surface wind speed range and a sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine the distribution of sea wave energy.

[0109] The extracting module 320 is configured to extract, under the limitation of the sea surface condition range and the wave direction angle range, a sea wave fluctuation spectrum of a non-track area to obtain a non-track area speckle noise spectrum.

[0110] Optionally, the determining module is specifically configured to:

[0111] In the sea state of the single sea wave component, the sea surface wind speed is determined when the sea wave fluctuation spectrum extracted by the wave spectrum instrument is affected by the nonlinear modulation less than a preset condition, that is, the minimum value of the sea surface wind speed range.

[0112] Optionally, the determining module is specifically configured to:

[0113] In the sea state of the single sea wave component, the sea surface condition range is determined when the sea wave energy density spectrum density is less than a preset density; and the wave direction angle range is determined when the value of the direction function is less than a preset function value.

[0114] Optionally, the determining module is specifically configured to:

[0115] In the pure wind wave sea state, the sea surface wind speed is determined when the sea wave energy density spectrum density is less than a preset density; and in the pure swell sea state, the sea wave effective wave height is determined when the sea wave energy density spectrum density is less than a preset density, that is, the maximum value of the sea surface wind speed range and the maximum value of the sea wave effective wave height range.

[0116] Optionally, the determining module is specifically configured to:

[0117] According to the sea wave detection azimuth interval value of the wave spectrum instrument and the wave direction angle when the value of the direction function is less than a preset function value, the wave direction angle range is determined.

[0118] Optionally, the determining module is specifically configured to:

[0119] The minimum value of the sea surface wind speed range when the sea wave energy density spectrum density is less than the preset density is determined as 5 m / s, and the maximum value is determined as 10 m / s; the minimum value of the sea wave effective wave height range when the sea wave energy density spectrum density is less than the preset density is determined as 0, and the maximum value is determined as 1 m; the difference between the wave direction angle and the sea wave detection azimuth interval value of the wave spectrum instrument when the directional function is the minimum value, and the sum of the wave direction angle and the sea wave detection azimuth interval value of the wave spectrum instrument when the directional function is the minimum value, then the minimum value of the wave direction angle range is 82.5°, and the maximum value is 97.5°.

[0120] Optionally, the extraction module is specifically configured to:

[0121] The sea wave fluctuation spectrum sample under the limitation of the sea surface condition range and the wave direction angle range is selected; the mean value of the sea wave fluctuation spectrum sample is calculated to obtain the non-in-track area speckle noise spectrum.

[0122] Please refer to Figure 4 A structure diagram of a device for extracting a non-in-track area speckle noise spectrum provided in an embodiment of the present application, the device can include a memory 410 and a processor 420. Optionally, the device can also include a communication interface 430 and a communication bus 440. The device corresponds to the above-mentioned Figure 1 method embodiment, and can execute Figure 1 each step involved in the method embodiment, and the specific functions of the device can be referred to the description below.

[0123] Specifically, the memory 410 is configured to store computer readable instructions.

[0124] The processor 420 is configured to process the readable instructions stored in the memory, and can execute each step in the Figure 1 method.

[0125] The communication interface 430 is configured to perform signaling or data communication with other node devices. For example, it is configured to perform communication with a server or a terminal, or communication with other device nodes, and the embodiments of the present application are not limited thereto.

[0126] The communication bus 440 is configured to realize direct connection communication of the above-mentioned components.

[0127] In the embodiments of the present application, the communication interface 430 of the device is configured to perform signaling or data communication with other node devices. The memory 410 can be a high-speed RAM memory, or a non-volatile memory such as at least one disk memory. The memory 410 can also be at least one storage device located away from the aforementioned processor. The memory 410 stores computer readable instructions, and when the computer readable instructions are executed by the processor 420, the electronic device executes the above-mentioned Figure 1The processor 420 can be used on the device 300 and used to perform the functions in the present application. For example, the processor 420 described above can be a general processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, and the embodiments of the present application are not limited thereto.

[0128] The embodiments of the present application further provide a readable storage medium, when the computer program is executed by the processor, the method is executed as Figure 1 The embodiments of the present application further provide a readable storage medium, when the computer program is executed by the processor, the method is executed as

[0129] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the foregoing method, and will not be repeated here.

[0130] In summary, the embodiments of the present application provide a method, device and equipment for extracting a speckle noise spectrum of a non-track area, the method comprising: determining a sea surface condition range when a sea wave energy density spectrum density is less than a preset density and a wave direction angle range when a value of a direction function is less than a preset function value, under a sea condition of a single sea wave component, wherein the single sea wave component comprises pure wind wave or pure swell, the sea surface condition range comprises a sea surface wind speed range and a sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine a distribution of sea wave energy; and extracting a sea wave fluctuation spectrum of the non-track area under the limitation of the sea surface condition range and the wave direction angle range, to obtain a speckle noise spectrum of the non-track area. The method can improve the accuracy of extracting the speckle noise spectrum of the non-track area.

[0131] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can also be implemented by other means. The apparatus embodiments described above are only illustrative, for example, the flowcharts and block diagrams in the drawings show the possible implementation architecture, function and operation of the apparatus, method and computer program product according to the embodiments of the present application. In this regard, each block in the flowchart or block diagram can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logic function. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur in different order from that shown in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0132] In addition, the functional modules in the various embodiments of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0133] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various program code storage media.

[0134] The above merely provides an example of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0135] The above merely provides an example of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and thus, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings.

[0136] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

Claims

1. A method of extracting a spectrum of speckle noise in a non-track area, characterized by, The method comprises the following steps: In a sea state of a single sea wave component, determining a sea surface condition range when a sea wave energy density spectrum density is less than a preset density and a wave direction angle range when a value of a direction function is less than a preset function value, wherein the single sea wave component comprises pure wind wave or pure swell, the sea surface condition range comprises a sea surface wind speed range and a sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine a distribution of sea wave energy; Under the limitation of the sea surface condition range and the wave direction angle range, extracting a sea wave fluctuation spectrum of a non-track area to obtain a non-track area speckle noise spectrum.

2. The method of claim 1, wherein, The method of determining the sea surface condition range when the sea wave energy density spectrum density is less than the preset density and the wave direction angle range when the value of the direction function is less than the preset function value in the sea state of the single sea wave component comprises: In the sea state of the single sea wave component, determining a sea surface wind speed when a sea wave fluctuation spectrum extracted by a wave spectrum instrument is affected by nonlinear modulation less than a preset condition, that is, a minimum value of the sea surface wind speed range.

3. The method according to claim 1 or 2, characterized in that, The method of determining the sea surface condition range when the sea wave energy density spectrum density is less than the preset density and the wave direction angle range when the value of the direction function is less than the preset function value in the sea state of the single sea wave component comprises: In the sea state of the single sea wave component, determining the sea surface condition range when the sea wave energy density spectrum density is less than the preset density; Determining the wave direction angle range when the value of the direction function is less than the preset function value.

4. The method of claim 3, wherein, The method of determining the sea surface condition range when the sea wave energy density spectrum density is less than the preset density comprises: In a pure wind wave sea state, determining a sea surface wind speed when the sea wave energy density spectrum density is less than the preset density; in a pure swell sea state, determining a sea wave effective wave height when the sea wave energy density spectrum density is less than the preset density, that is, a maximum value of the sea surface wind speed range and a maximum value of the sea wave effective wave height range.

5. The method of claim 3, wherein, The method of determining the wave direction angle range when the value of the direction function is less than the preset function value comprises: According to a sea wave detection azimuth interval value of a wave spectrum instrument and a wave direction angle when the value of the direction function is less than the preset function value, determining the wave direction angle range.

6. The method of claim 1 or 2, wherein, The method of determining the sea surface condition range when the sea wave energy density spectrum density is less than the preset density and the wave direction angle range when the value of the direction function is less than the preset function value in the sea state of the single sea wave component comprises: Determining a minimum value of the sea surface wind speed range to be 5 m / s and a maximum value to be 10 m / s when the sea wave energy density spectrum density is less than the preset density; Determining a minimum value of the sea wave effective wave height range to be 0 and a maximum value to be 1 m when the sea wave energy density spectrum density is less than the preset density; Determining a difference between a wave direction angle when the direction function is a minimum value and a sea wave detection azimuth interval value of a wave spectrum instrument and a sum of the wave direction angle when the direction function is the minimum value and the sea wave detection azimuth interval value of the wave spectrum instrument, and a minimum value of the wave direction angle range is 82.5° and a maximum value is 97.5°.

7. The method according to claim 1 or 2, characterized in that, The method of extracting the sea wave fluctuation spectrum of the non-track area under the limitation of the sea surface condition range and the wave direction angle range to obtain the non-track area speckle noise spectrum comprises: selecting a sea wave fluctuation spectrum sample under the limitation of the sea surface condition range and the wave direction angle range; calculating the mean value of the sea wave fluctuation spectrum sample to obtain the non-track area speckle noise spectrum.

8. An apparatus for extracting a spectrum of speckle noise in a non-track area, characterized by comprising: The method comprises the steps of: determining, in a sea state with a single sea wave component, a sea surface condition range in which the sea wave energy density spectrum density is less than a preset density and a wave direction angle range in which the value of a direction function is less than a preset function value, wherein the single sea wave component comprises pure wind wave or pure swell, the sea surface condition range comprises a sea surface wind speed range and a sea wave effective wave height range, and the sea wave energy density spectrum density and the value of the direction function are used to determine the distribution of sea wave energy; extracting, under the limitation of the sea surface condition range and the wave direction angle range, a sea wave fluctuation spectrum of a non-track area to obtain a non-track area speckle noise spectrum.

9. An electronic device, comprising: The method comprises the steps of: a memory and a processor, wherein the memory stores computer readable instructions, and when the computer readable instructions are executed by the processor, the steps in the method according to any one of claims 1-7 are performed.

10. A computer-readable storage medium, characterized in that, The computer program, when executed on a computer, causes the computer to perform the method according to any one of claims 1-7. ​

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