Method, device and equipment for extracting spot noise spectrum of track area and storage medium

Abstract

The application provides a method, device, equipment and storage medium for extracting a spectrum of spot noise in a along-track area, which comprises the following steps: when the along-track direction is perpendicular to the sea wave propagation direction, determining a boundary spectrum of spot noise of the along-track area and a non-along-track area by using a spectrum of spot noise in the non-along-track area; determining a sea wave modulation spectrum of the along-track area under a corresponding relative observation angle by using the boundary spectrum of spot noise; determining a spectrum of spot noise in the along-track area under the relative observation angle by using the sea wave modulation spectrum of the along-track area; and determining a spectrum of spot noise in a target observation angle of a target along-track area under the same sea surface condition by using the spectra of spot noise in the along-track area under different relative observation angles, wherein the sea surface condition comprises a sea surface wind speed and an effective wave height. The method can improve the accuracy of extracting the spectrum of spot noise in the along-track area.

Description

Technical Field

[0001] The present application relates to the field of extracting speckle noise spectrum, and in particular, to a method, apparatus, device and storage medium for extracting speckle noise spectrum in an along-track area. Background Art

[0002] Currently, studying many dynamic processes in the ocean requires precise information about ocean waves. Ocean waves are random and can be considered a random process. Currently, the most effective way to describe ocean waves is the wave directional spectrum, which is defined as the distribution of wave energy with respect to frequency and direction. The wave directional spectrum not only characterizes the distribution of wave energy in various directions but can also be used to calculate various wave parameters, such as significant wave height and main wave direction. Therefore, obtaining accurate speckle noise spectrum samples in the along-track region is a key task in wave research. Existing empirical methods directly use along-track wave spectrum samples to represent along-track speckle noise spectrum samples.

[0003] The above-mentioned basic method has great limitations. The wave spectrum often contains the wave modulation spectrum. Especially when the sea conditions are large or the along-track area is located near the wave direction, the wave modulation spectrum is large, resulting in inaccurate speckle noise spectrum obtained subsequently.

[0004] Therefore, how to improve the accuracy of extracting the speckle noise spectrum in the along-track area is a technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of the embodiments of the present application is to provide a method for extracting the speckle noise spectrum of the along-track area. Through the technical solution of the embodiments of the present application, the accuracy of extracting the speckle noise spectrum of the along-track area can be improved.

[0006] In a first aspect, an embodiment of the present application provides a method for extracting a speckle noise spectrum of an along-track area, comprising: when the along-track direction is perpendicular to the wave propagation direction, determining the boundary speckle noise spectrum of the along-track area and the non-along-track area through the speckle noise spectrum of the non-along-track area; determining the wave modulation spectrum of the along-track area under the corresponding relative observation angle through the boundary speckle noise spectrum; determining the speckle noise spectrum of the along-track area under each relative observation angle through the wave modulation spectrum of the along-track area; and determining the speckle noise spectrum of the target along-track area under the target observation angle under the same sea surface conditions through the speckle noise spectrum of the along-track area under each relative observation angle, wherein the sea surface conditions include sea surface wind speed and effective wave height of waves.

[0007] In the above embodiments of the present application, the speckle noise spectrum of the non-extended track area and the along-track area boundary can be determined through the speckle noise spectrum of the non-extended track area, and then the wave modulation spectrum of the non-extended track area and the along-track area boundary can be obtained. The speckle noise spectrum of the along-track area under the relative observation angle can be determined in the lateral wave direction, that is, the speckle noise spectrum of the target along-track area under the relative observation angle. The above method can be used to remove the wave modulation spectrum in the wave fluctuation spectrum, and then an accurate speckle noise spectrum can be obtained, thereby achieving the effect of improving the accuracy of extracting the speckle noise spectrum of the along-track area.

[0008] In some embodiments, under the same sea surface conditions, the speckle noise spectrum of the along-track area and the speckle noise spectrum of the target along-track area at the target observation angle are the same.

[0009] When the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum in the along-track area remains unchanged;

[0010] The speckle noise spectrum in the non-along-track area is the same as that in the boundary area.

[0011] In the above process, according to the above principle of invariant conditions, the wave modulation spectrum in the along-track area can be accurately determined by the boundary wave modulation spectrum between the along-track area and the non-track area when the along-track direction is perpendicular to the wave propagation direction.

[0012] In some embodiments, when the along-track direction is perpendicular to the wave propagation direction, before determining the boundary speckle noise spectrum between the along-track region and the non-along-track region using the speckle noise spectrum of the non-along-track region, the method further includes:

[0013] Under the sea condition of a single wave component, wave fluctuation spectrum samples within the preset sea surface conditions and the preset wave direction angle range are selected as the speckle noise spectrum of the non-track area.

[0014] In the above process, the embodiment of the present application can measure the wave fluctuation spectrum samples as the non-along-track area speckle noise spectrum under the preset sea surface conditions and the preset wave direction angle range.

[0015] In some embodiments, determining the wave modulation spectrum of the along-track area corresponding to the relative observation angle by using the boundary speckle noise spectrum includes:

[0016] The boundary wave modulation spectrum of the along-track area and the non-along-track area is determined by the boundary speckle noise spectrum;

[0017] The wave modulation spectrum in the area along the track is determined by the boundary wave modulation spectrum.

[0018] In the above process of the embodiment of the present application, when the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum of the entire along-track area can be accurately determined according to the principle that the wave modulation spectrum of the along-track area remains unchanged.

[0019] In some embodiments, determining the speckle noise spectrum of the along-track area at each relative observation angle using the wave modulation spectrum of the along-track area includes:

[0020] Obtain the wave spectrum of the along-track area corresponding to the relative observation angle;

[0021] The wave modulation spectrum along the track area is removed from the wave fluctuation spectrum along the track area to obtain the speckle noise spectrum along the track area.

[0022] In the above process, the embodiment of the present application can remove the wave modulation spectrum from the acquired wave fluctuation spectrum, and accurately obtain the speckle noise spectrum of the along-track area.

[0023] In some embodiments, the speckle noise spectrum of the along-track region at each relative observation angle is obtained by the following formula:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030] Where k represents the wave number, represents the relative observation angle used to divide the along-track area and the non-along-track area, represents any observation angle under the relative observation angles, The relative observation angle is The boundary speckle noise spectrum when represents the speckle noise spectrum in the non-along-track area, The relative observation angle is The boundary wave spectrum between the trackside area and the non-trackside area is: The relative observation angle is The boundary wave modulation spectrum between the along-track area and the non-along-track area is: The relative observation angle is The wave modulation spectrum of the area along the track is The relative observation angle is The wave spectrum of the area along the track is: The relative observation angle is The wave modulation spectrum of the area along the track, P IR(k) represents the wave impulse response spectrum, The relative observation angle is The speckle noise spectrum of the along-track area is shown in FIG.

[0031] In the above process, the embodiment of the present application uses the above algorithm to accurately calculate the speckle noise spectrum of the along-track area, and further accurately determine the speckle noise spectrum of the target along-track area when the relative observation angle remains unchanged.

[0032] In a second aspect, an embodiment of the present application provides a device for extracting a speckle noise spectrum in an along-track area, comprising:

[0033] The first determination module is configured to determine the boundary speckle noise spectrum of the along-track area and the non-along-track area based on the speckle noise spectrum of the non-along-track area when the along-track direction is perpendicular to the wave propagation direction;

[0034] The second determination module is used to determine the wave modulation spectrum of the along-track area corresponding to the relative observation angle through the boundary speckle noise spectrum;

[0035] The third determination module is configured to determine the speckle noise spectrum of the along-track area at each relative observation angle based on the wave modulation spectrum of the along-track area;

[0036] The fourth determination module is used to determine the speckle noise spectrum of the target along-track area at the target observation angle through the speckle noise spectrum of the along-track area at each relative observation angle under the same sea surface conditions, wherein the sea surface conditions include sea surface wind speed and wave effective wave height.

[0037] Optionally, under the same sea surface conditions, the speckle noise spectrum of the along-track area at the target observation angle is the same as the speckle noise spectrum of the target along-track area;

[0038] When the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum in the along-track area remains unchanged;

[0039] The speckle noise spectrum in the non-along-track area is the same as that in the boundary area.

[0040] Optionally, the device further includes:

[0041] A screening module is used for selecting, under sea conditions with a single wave component, wave fluctuation spectrum samples within preset sea surface conditions and within preset wave direction angle ranges as the speckle noise spectrum of the non-track area before the first determination module determines the boundary speckle noise spectrum of the along-track area and the non-track area through the speckle noise spectrum of the non-track area when the along-track direction is perpendicular to the wave propagation direction.

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

[0043] The boundary wave modulation spectrum of the along-track area and the non-along-track area is determined by the boundary speckle noise spectrum;

[0044] The wave modulation spectrum in the area along the track is determined by the boundary wave modulation spectrum.

[0045] Optionally, the third determining module is specifically configured to:

[0046] Obtain the wave spectrum of the along-track area relative to the observation angle;

[0047] The wave modulation spectrum along the track area is removed from the wave fluctuation spectrum along the track area to obtain the speckle noise spectrum along the track area.

[0048] Optionally, the speckle noise spectrum of the along-track area at each relative observation angle is obtained by the following formula:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055] Where k represents the wave number, represents the relative observation angle used to divide the along-track area and the non-along-track area, represents any observation angle under the relative observation angles, The relative observation angle is The boundary speckle noise spectrum when represents the speckle noise spectrum in the non-along-track area, The relative observation angle is The boundary wave spectrum between the trackside area and the non-trackside area is: The relative observation angle is The boundary wave modulation spectrum between the along-track area and the non-along-track area is: The relative observation angle is The wave modulation spectrum of the area along the track is The relative observation angle is The wave spectrum of the area along the track is: The relative observation angle is The wave modulation spectrum of the area along the track, P IR (k) represents the wave impulse response spectrum, The relative observation angle is The speckle noise spectrum of the along-track area is shown in FIG.

[0056] In a third aspect, an embodiment of the present application provides an electronic device comprising a processor and a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the steps in the method provided in the first aspect above are executed.

[0057] In a fourth aspect, an embodiment of the present application provides a readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps in the method provided in the first aspect are executed.

[0058] Other features and advantages of the present application will be described in the following description and, in part, will become apparent from the description or be understood by practicing the embodiments of the present application. The objectives and other advantages of the present application can be achieved and obtained through the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0060] Figure 1 A flowchart of a method for extracting speckle noise spectrum in an along-track area provided in an embodiment of the present application;

[0061] Figure 2 A flowchart of an implementation method for extracting speckle noise spectrum in an along-track area provided in an embodiment of the present application;

[0062] Figure 3 A schematic block diagram of an apparatus for extracting speckle noise spectrum in an along-track area provided in an embodiment of the present application;

[0063] Figure 4 A schematic diagram of the structure of a device for extracting speckle noise spectrum in an along-track area provided in an embodiment of the present application. DETAILED DESCRIPTION

[0064] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with 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 of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here 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 application for protection, but merely represents the 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 making creative work fall within the scope of protection of the present application.

[0065] 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 or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0066] First, some of the terms involved in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

[0067] Terminal device: can be a mobile terminal, fixed terminal or portable terminal, such as a mobile phone, station, unit, device, multimedia computer, multimedia tablet, Internet node, communicator, desktop computer, laptop computer, notebook computer, netbook computer, tablet computer, personal communication system device, personal navigation device, personal digital assistant, audio / video player, digital camera / camcorder, positioning device, television receiver, radio broadcast receiver, e-book device, gaming 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 user interface (such as wearable device), etc.

[0068] Server: It can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, and big data and artificial intelligence platforms.

[0069] Spectrometer: SWIM (Surface Wave Investigation and Monitoring) is the world's first spaceborne microwave radar focused on ocean wave spectrum detection. SWIM illuminates the sea surface with six beams, 0°, 2°, 4°, 6°, 8°, and 10°, with the antenna rotating between 0 and 360°. Adjacent azimuths within the same beam are separated by 220ms, with a 7.5° azimuth interval. Signals from adjacent azimuths are incoherent, making it impossible to accurately measure and remove speckle noise using the cross-spectral method.

[0070] Speckle noise spectrum: The distribution of speckle noise with direction and frequency.

[0071] Spaceborne Spectrometer: SWIM (Surface Wave Investigation and Monitoring) is the world's first spaceborne microwave radar focused on ocean wave spectrum detection. SWIM illuminates the sea surface with six beams, sequentially at 0°, 2°, 4°, 6°, 8°, and 10°, with the antenna rotating between 0 and 360°. Adjacent macrocycles within the same beam are separated by 220ms and 7.5° in azimuth. Signals from adjacent macrocycles are incoherent, making it impossible to accurately measure and remove speckle noise using the cross-spectral method.

[0072] The ocean wave spectrum describes the distribution of energy within a wave relative to frequency and direction. Also known as the ocean energy spectrum, it is a key concept in the study of ocean waves. The wave spectrum not only reveals the internal composition of a wave but also provides information about its external characteristics.

[0073] Wave modulation spectrum: The spectrometer transmits a linear frequency modulation signal to the sea surface and receives the backscattered signal from the sea surface. The wave modulation spectrum can be obtained by calculating the Fourier transform of the autocorrelation.

[0074] The present application is applied to the scenario of extracting speckle noise spectrum. The specific scenario is to determine the speckle noise spectrum of the side wave area of ​​the vertical wave at the relative observation angle, and then determine the speckle noise spectrum of the target along-track area at the same relative observation angle.

[0075] Currently, the study of many dynamic processes in the ocean requires precise information about ocean waves. Ocean waves are random and can be considered a random process. Currently, the most effective way to describe ocean waves is the wave propagation directional spectrum, which is defined as the distribution of ocean wave energy with respect to frequency and direction. The wave propagation directional spectrum not only characterizes the distribution of ocean wave energy in various directions, but can also be used to calculate various wave parameters, such as significant wave height and main wave direction. Therefore, obtaining accurate speckle noise spectrum samples in the along-track area is one of the key tasks in ocean wave research. Existing empirical methods directly use along-track area wave spectrum samples to represent along-track area speckle noise spectrum samples. The above-mentioned basic method has significant limitations. The wave spectrum often contains the wave modulation spectrum. In particular, when the sea conditions are large or the along-track area is located near the wave direction, the wave modulation spectrum is large, resulting in inaccurate speckle noise spectrum obtained subsequently.

[0076] To this end, the present application determines the boundary speckle noise spectrum of the along-track area and the non-along-track area by using the speckle noise spectrum of the non-along-track area when the along-track direction is perpendicular to the wave propagation direction; determines the wave modulation spectrum of the along-track area under the corresponding relative observation angle by using the boundary speckle noise spectrum; determines the speckle noise spectrum of the along-track area under each relative observation angle by using the wave modulation spectrum of the along-track area; determines the speckle noise spectrum of the target along-track area under the target observation angle by using the speckle noise spectrum of the along-track area under each relative observation angle under the same sea surface conditions, wherein the sea surface conditions include sea surface wind speed and effective wave height of the waves. The speckle noise spectrum of the boundary between the non-extended track area and the along-track area can be determined by using the speckle noise spectrum of the non-extended track area, and then the wave modulation spectrum of the boundary between the non-extended track area and the along-track area can be obtained. The speckle noise spectrum of the along-track area under the relative observation angle can be determined in the lateral wave direction, that is, the speckle noise spectrum of the target along-track area under the relative observation angle. The above method can remove the wave modulation spectrum in the wave fluctuation spectrum, and then obtain an accurate speckle noise spectrum, thereby achieving the effect of improving the accuracy of extracting the speckle noise spectrum of the along-track area.

[0077] In the embodiment of the present application, the execution entity may be a device for extracting speckle noise spectrum in the along-track area in the system for extracting speckle noise spectrum in the along-track area. In actual applications, the device for extracting speckle noise spectrum in the along-track area may be an electronic device such as a terminal device and a server, and no limitation is made here.

[0078] The following combination Figure 1 The method for extracting the speckle noise spectrum of the along-track area in an embodiment of the present application is described in detail.

[0079] Please see Figure 1 , Figure 1 A flowchart of a method for extracting speckle noise spectrum along the track area provided in an embodiment of the present application is shown as follows: Figure 1 The method for extracting the speckle noise spectrum of the along-track area shown includes:

[0080] Step 110: When the along-track direction is perpendicular to the wave propagation direction, the boundary speckle noise spectrum between the along-track area and the non-along-track area is determined by the speckle noise spectrum of the non-along-track area.

[0081] The direction perpendicular to the wave propagation direction can also be called the side wave direction, which is the along-track direction. The along-track direction is the along-track direction perpendicular to the wave propagation direction, and can be the current satellite's flight trajectory. The speckle noise spectrum of the along-track region when the along-track direction is perpendicular to the wave propagation direction can be used to determine the speckle noise spectrum of the along-track region of the current satellite's flight. The off-track region can be any region outside the satellite's flight area. The boundary speckle noise spectrum represents the speckle noise spectrum at the boundary between the on-track and off-track regions.

[0082] In some embodiments of the present application, under the same sea surface conditions, the speckle noise spectrum of the along-track area at the target observation angle is the same as the speckle noise spectrum of the target along-track area; when the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum on the along-track area remains unchanged; the speckle noise spectrum of the non-along-track area is the same as the boundary speckle noise spectrum.

[0083] In the above process of the embodiment of the present application, through the above-mentioned principle of unchanged conditions, the speckle noise spectrum of the along-track area under the relative observation angle can be determined under the condition that the sea surface conditions remain unchanged, that is, the speckle noise spectrum of the target along-track area can be accurately obtained. When the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum of the along-track area can be accurately determined through the boundary wave modulation spectrum between the along-track area and the non-track area. When the speckle noise spectrum of the non-track area remains unchanged, the boundary speckle noise spectrum of the along-track area and the non-track area can be accurately determined.

[0084] Sea surface conditions include wind speed and significant wave height. The relative observation angle represents the angle between the flight angle of the satellite carrying the spectrometer and the observation azimuth of the onboard spectrometer. While the leading-track region represents the along-track region under the current satellite's flight trajectory, the along-track region represents the region in the direction of side waves perpendicular to the wave propagation direction. This region may represent the along-track region formed when the satellite flies along the direction of side waves. The boundary between the along-track region and the non-along-track region belongs to both the along-track region and the non-along-track region. This boundary can be determined by the principle that the speckle noise spectrum of the non-along-track region is the same, i.e., the speckle noise spectrum of the non-along-track region does not change with relative observation angle, sea surface conditions, or sea state. The speckle noise spectrum of the along-track region decreases with increasing relative observation angle. When the relative observation angle reaches a threshold, the speckle noise spectrum no longer changes with increasing relative observation angle. The region under this relative observation angle is then used to divide the along-track region and the non-along-track region.

[0085] In some embodiments of the present application, when the along-track direction is perpendicular to the wave propagation direction, before determining the boundary speckle noise spectrum between the along-track region and the non-along-track region by the speckle noise spectrum of the non-along-track region, Figure 1 The method shown also includes: under sea conditions with a single wave component, selecting wave fluctuation spectrum samples within preset sea surface conditions and preset wave direction angle range limits as non-along-track area speckle noise spectra.

[0086] In the above process, the embodiment of the present application can measure the wave fluctuation spectrum samples as the non-along-track area speckle noise spectrum under the preset sea surface conditions and the preset wave direction angle range.

[0087] Sea conditions with a single wave component include pure wind waves or pure swell waves. Preset sea surface conditions include a preset sea surface wind speed range and a preset wave significant wave height range. The preset wave direction angle represents the angle range between the spectrometer's observation angle and the wave propagation direction. The speckle noise spectrum can be more accurately determined when the wave energy is minimal, the wave modulation spectrum in the wave fluctuation spectrum is minimal, or even absent.

[0088] Step 120: Determine the wave modulation spectrum of the along-track area corresponding to the relative observation angle through the boundary speckle noise spectrum.

[0089] Among them, the wave fluctuation spectrum at different positions along the track area is different, and the wave fluctuation spectrum can be directly measured by the satellite-borne spectrometer.

[0090] In some embodiments of the present application, the wave modulation spectrum of the along-track area corresponding to the relative observation angle is determined by the boundary speckle noise spectrum, including: determining the boundary wave modulation spectrum of the along-track area and the non-along-track area by the boundary speckle noise spectrum; determining the wave modulation spectrum of the along-track area by the boundary wave modulation spectrum.

[0091] In the above process of the present application, when the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum of the entire along-track area can be accurately determined by the principle that the wave modulation spectrum of the along-track area is unchanged.

[0092] Among them, the wave fluctuation spectrum at the boundary between the along-track area and the non-track area can be obtained through a satellite-borne spectrometer. According to the principle that the speckle noise spectrum of the non-track area remains unchanged when the sea surface conditions and wave direction angle remain unchanged, the speckle noise spectrum of the non-track area in the boundary wave fluctuation spectrum can be removed to obtain the boundary wave modulation spectrum. According to the principle that the wave modulation spectrum of the along-track area remains unchanged when the along-track direction is perpendicular to the wave propagation direction, the boundary wave modulation spectrum, i.e., the wave modulation spectrum of the along-track area, can be obtained.

[0093] Step 130: Determine the speckle noise spectrum of the along-track area at each relative observation angle through the wave modulation spectrum of the along-track area.

[0094] In some embodiments of the present application, the speckle noise spectrum of the along-track area at each relative observation angle is determined through the wave modulation spectrum of the along-track area, including: obtaining the wave fluctuation spectrum of the along-track area at the relative observation angle; removing the wave modulation spectrum of the along-track area from the wave fluctuation spectrum of the along-track area to obtain the speckle noise spectrum of the along-track area.

[0095] In the above process, the present application can remove the wave modulation spectrum from the acquired wave fluctuation spectrum, and accurately obtain the speckle noise spectrum of the along-track area.

[0096] Among them, the wave fluctuation spectrum of the along-track area under a certain relative observation angle can be obtained through the satellite-borne spectrometer.

[0097] In some embodiments of the present application, the speckle noise spectrum of the along-track region at each relative observation angle is obtained by the following formula:

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] Where k represents the wave number, represents the relative observation angle used to divide the along-track area and the non-along-track area, represents any observation angle under the relative observation angles, The relative observation angle is The boundary speckle noise spectrum when represents the speckle noise spectrum in the non-along-track area, The relative observation angle is The boundary wave spectrum between the trackside area and the non-trackside area is: The relative observation angle is The boundary wave modulation spectrum between the along-track area and the non-along-track area is: The relative observation angle is The wave modulation spectrum of the area along the track is The relative observation angle is The wave spectrum of the area along the track is: The relative observation angle is The wave modulation spectrum of the area along the track, P IR(k) represents the wave impulse response spectrum, The relative observation angle is The speckle noise spectrum of the along-track area is shown in FIG.

[0105] In the above process, the present application can accurately calculate the speckle noise spectrum of the along-track area through the above algorithm, and then accurately determine the speckle noise spectrum of the target along-track area when the relative observation angle remains unchanged.

[0106] Where n is P n The wave spectrum index of the area along the track; a and sp are Boundary speckle noise spectrum index; n and sp are The speckle noise spectrum index of the non-along-track area; z is P z Boundary wave spectrum index; IR is P IR (k) Ocean wave impact spectrum index; m is P m The wave modulation spectrum index of the along-track area; s and a are The speckle noise spectrum of the along-track area decreases sharply with the increase of the relative observation angle until it reaches a certain angle. At this time, the speckle noise spectrum no longer changes with the increase of the relative observation angle, and Divide the track area and non-track area. Under different sea surface conditions and sea conditions, The sizes are different. Considering that the azimuth interval of the satellite-borne spectrometer is 7.5°, the The value of, for example, can be 15°.

[0107] Step 140: Under the same sea surface conditions, determine the speckle noise spectrum of the target along-track area at the target observation angle through the speckle noise spectrum of the along-track area at each relative observation angle.

[0108] Sea surface conditions include wind speed and significant wave height. Given that the speckle noise spectrum remains the same when the sea surface conditions and relative observation angle remain unchanged, the speckle noise spectrum in the side wave direction can be used as the speckle noise spectrum in the target along-track region.

[0109] In the above Figure 1In the process, the present application determines the boundary speckle noise spectrum of the along-track region and the off-track region by the speckle noise spectrum of the off-track region when the track direction is perpendicular to the wave propagation direction, determines the wave modulation spectrum of the along-track region under the corresponding relative observation angle by the boundary speckle noise spectrum, determines the speckle noise spectrum of the along-track region under each relative observation angle by the wave modulation spectrum of the along-track region, and determines the speckle noise spectrum of the target observation angle of the target along-track region under the same sea surface condition, wherein the sea surface condition includes the sea surface wind speed and the effective wave height. The speckle noise spectrum of the boundary between the off-track region and the along-track region can be determined by the speckle noise spectrum of the off-track region, and then the wave modulation spectrum of the boundary between the off-track region and the along-track region is obtained, and the speckle noise spectrum of the along-track region under the relative observation angle, i.e., the speckle noise spectrum of the target along-track region under the relative observation angle, can be determined in the side wave direction. The wave modulation spectrum in the wave fluctuation spectrum can be removed by the above method, and then the accurate speckle noise spectrum is obtained, and the effect of improving the accuracy of extracting the speckle noise spectrum of the along-track region is achieved.

[0110] In some embodiments of the present application, the speckle noise spectrum of the along-track region is extracted at the relative observation angles of 0°, 5° and 15° by steps 110-140 and the traditional method in sequence. Four types of sea surface conditions are used as follows:

[0111] H s <2m, U 10 <5m / s H s <2m, 5m / s<U 10 <10m / s; 2m<H s <4m, 0m / s<U 10 <10m / s; H s >4m or U 10 >10m / s.

[0112] wherein H s is the effective wave height, and U 10 is the wind speed. It is proved that, compared with the existing empirical method, the speckle noise spectrum of the along-track region extracted by the method of the present application can effectively remove the wave modulation spectrum in the fluctuation spectrum of the along-track region, and accurately extract the speckle noise spectrum of the along-track region, whether in smaller sea conditions (the first and second types of sea surface conditions) or in larger sea conditions (the third and fourth types of sea surface conditions).

[0113] The implementation method of extracting the speckle noise spectrum of the along-track region according to the embodiments of the present application will be described in detail below. Figure 2

[0114] Please refer to Figure 2 , Figure 2 The flowchart of an implementation method of extracting the speckle noise spectrum of the along-track region provided by the embodiments of the present application is as follows:​ Figure 2 The method for extracting the along-track region's speckle noise spectrum comprises the following steps:

[0115] Step 210: determining the boundary speckle noise spectrum of the along-track region and the off-track region.

[0116] Specifically, when the along-track direction is perpendicular to the sea wave propagation direction, the boundary speckle noise spectrum of the along-track region and the off-track region is determined by the off-track region's speckle noise spectrum.

[0117] Step 220: determining the sea wave modulation spectrum of the along-track region under the relative observation angle.

[0118] Specifically, the sea wave modulation spectrum of the along-track region under the corresponding relative observation angle is determined by the boundary speckle noise spectrum.

[0119] Step 230: determining the speckle noise spectrum of the along-track region under each relative observation angle.

[0120] Specifically, the speckle noise spectrum of the along-track region under each relative observation angle is determined by the sea wave modulation spectrum of the along-track region.

[0121] Step 240: determining the speckle noise spectrum of the target along-track region under the target observation angle.

[0122] Specifically, under the same sea surface condition, the speckle noise spectrum of the target along-track region under the target observation angle is determined by the speckle noise spectrum of the along-track region under each relative observation angle.

[0123] In addition, Figure 2 The specific method and steps shown can be referred to Figure 1 The method shown will not be described in detail here.

[0124] The foregoing describes the method for extracting the along-track region's speckle noise spectrum, and the following describes the device for extracting the along-track region's speckle noise spectrum. Figure 1-Figure 2 The foregoing describes the method for extracting the along-track region's speckle noise spectrum, and the following describes the device for extracting the along-track region's speckle noise spectrum. Figure 3-Figure 4 The foregoing describes the method for extracting the along-track region's speckle noise spectrum, and the following describes the device for extracting the along-track region's speckle noise spectrum.

[0125] Please refer to Figure 3 , which is a schematic block diagram of a device 300 for extracting the along-track region's speckle noise spectrum provided in the embodiments of the present application. The device 300 can be a module, a program segment or code on an electronic device. The device 300 corresponds to the method embodiments described above and can perform each step involved in the method embodiments described above. The specific functions of the device 300 can be referred to the description below, and the detailed description is appropriately omitted here to avoid repetition. Figure 1 The foregoing describes the method for extracting the along-track region's speckle noise spectrum, and the following describes the device for extracting the along-track region's speckle noise spectrum. Figure 1 The foregoing describes the method for extracting the along-track region's speckle noise spectrum, and the following describes the device for extracting the along-track region's speckle noise spectrum.

[0126] Optionally, the device 300 comprises:

[0127] The first determining module 310 is configured to determine a boundary spot noise spectrum of the along-track region and the off-track region by using the off-track region spot noise spectrum when the along-track direction is perpendicular to the sea wave propagation direction.

[0128] The second determining module 320 is configured to determine a sea wave modulation spectrum of the along-track region at a corresponding relative observation angle by using the boundary spot noise spectrum.

[0129] The third determining module 330 is configured to determine a spot noise spectrum of the along-track region at each relative observation angle by using the sea wave modulation spectrum of the along-track region.

[0130] The fourth determining module 340 is configured to determine a spot noise spectrum of the target along-track region at a target observation angle by using the spot noise spectrum of the along-track region at each relative observation angle under the same sea surface condition, wherein the sea surface condition includes a sea surface wind speed and a sea wave effective wave height.

[0131] Optionally, the spot noise spectrum of the target along-track region at the target observation angle is the same as the spot noise spectrum of the along-track region at the target observation angle under the same sea surface condition; the sea wave modulation spectrum on the along-track region is unchanged when the along-track direction is perpendicular to the sea wave propagation direction; and the off-track region spot noise spectrum is the same as the boundary spot noise spectrum.

[0132] Optionally, the device further comprises:

[0133] The screening module is configured to select a sea wave fluctuation spectrum sample under a preset sea surface condition and a preset wave direction angle range limit as the off-track region spot noise spectrum before the first determining module determines the boundary spot noise spectrum of the along-track region and the off-track region by using the off-track region spot noise spectrum when the along-track direction is perpendicular to the sea wave propagation direction.

[0134] Optionally, the second determining module is specifically configured to:

[0135] determine a boundary sea wave modulation spectrum of the along-track region and the off-track region by using the boundary spot noise spectrum; and determine the sea wave modulation spectrum of the along-track region by using the boundary sea wave modulation spectrum.

[0136] Optionally, the third determining module is specifically configured to:

[0137] obtain a sea wave fluctuation spectrum of the along-track region at a relative observation angle; and remove the sea wave modulation spectrum of the along-track region from the sea wave fluctuation spectrum of the along-track region to obtain the spot noise spectrum of the along-track region.

[0138] Optionally, the spot noise spectrum of the along-track region at each relative observation angle is obtained by using the following formula:

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145] Where k represents the wave number, represents the relative observation angle used to divide the along-track area and the non-along-track area, represents any observation angle under the relative observation angles, The relative observation angle is The boundary speckle noise spectrum when represents the speckle noise spectrum in the non-along-track area, The relative observation angle is The boundary wave spectrum between the trackside area and the non-trackside area is: The relative observation angle is The boundary wave modulation spectrum between the along-track area and the non-along-track area is: The relative observation angle is The wave modulation spectrum of the area along the track is The relative observation angle is The wave spectrum of the area along the track is: The relative observation angle is The wave modulation spectrum of the area along the track, P IR (k) represents the wave impulse response spectrum, The relative observation angle is The speckle noise spectrum of the along-track area is shown in FIG.

[0146] Please refer to Figure 4 This is a schematic diagram of the structure of a device for extracting speckle noise spectrum along the track area provided in an embodiment of the present application. The device may include a memory 410 and a processor 420. Optionally, the device may also include: a communication interface 430 and a communication bus 440. The device is similar to the above Figure 1 The method embodiment corresponds to the embodiment that can be executed Figure 1 The various steps involved in the method embodiment and the specific functions of the device can be found in the description below.

[0147] Specifically, the memory 410 is used to store computer-readable instructions.

[0148] Processor 420 is used to process the readable instructions stored in the memory and can execute Figure 1The steps in the method.

[0149] The communication interface 430 is used for signaling or data communication with other node devices, for example, for communication with a server or terminal, or for communication with other device nodes, but the embodiments of the present application are not limited thereto.

[0150] The communication bus 440 is used to realize direct connection and communication among the above components.

[0151] Among them, the communication interface 430 of the device in the embodiment of the present application is used to communicate signaling or data with other node devices. The memory 410 can be a high-speed RAM memory or a non-volatile memory (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. When the computer-readable instructions are executed by the processor 420, the electronic device executes the above-mentioned Figure 1 The method process shown. The processor 420 can be used on the device 300 and is used to perform the functions in the present application. Exemplarily, the above-mentioned processor 420 can be a general-purpose 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, or a discrete hardware component, but the embodiments of the present application are not limited thereto.

[0152] The embodiment of the present application further provides a readable storage medium, wherein when the computer program is executed by a processor, Figure 1 The method process in the illustrated method embodiment is performed by the electronic device.

[0153] Those skilled in the art will 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 aforementioned method, and will not be described in detail here.

[0154] In summary, the embodiment of the present application provides a method, device, equipment and storage medium for extracting a spot noise spectrum of a along-track area. When the along-track direction is perpendicular to the sea wave propagation direction, the boundary spot noise spectrum of the along-track area and a non-along-track area is determined by using a non-along-track area spot noise spectrum. The sea wave modulation spectrum of the along-track area corresponding to a relative observation angle is determined by using the boundary spot noise spectrum. The spot noise spectrum of the along-track area corresponding to each relative observation angle is determined by using the sea wave modulation spectrum of the along-track area. The spot noise spectrum of the target observation angle of the target along-track area is determined by using the spot noise spectrum of the along-track area corresponding to each relative observation angle under the same sea surface condition, wherein the sea surface condition includes the sea surface wind speed and the effective wave height. The method can improve the accuracy of extracting the spot noise spectrum of the along-track area.

[0155] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can also be implemented by other manners. The apparatus embodiments described above are only schematic, for example, the flow charts and block diagrams in the drawings show the possible implementation architectures, functions and operations of the apparatus, method and computer program product according to the embodiments of the present application. In this regard, each block in the flow charts or block diagrams can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logical functions. It should also be noted that, in some alternative implementations, the functions noted in the blocks can occur in different orders from those described 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 diagrams and / or flow charts, and the combination of blocks in the block diagrams and / or flow charts, can be implemented by a dedicated hardware-based system, or by a combination of dedicated hardware and computer instructions.

[0156] In addition, each functional module in the 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.

[0157] 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 solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling 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 method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0158] The foregoing is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures.

[0159] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

[0160] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

Claims

1. A method for extracting speckle noise spectrum in the along-track area, characterized in that: include: When the along-track direction is perpendicular to the wave propagation direction, the speckle noise spectrum of the boundary between the along-track area and the non-along-track area is determined by the speckle noise spectrum of the non-along-track area. Determining the wave modulation spectrum of the along-track area corresponding to the relative observation angle by using the boundary speckle noise spectrum; determining a speckle noise spectrum of the along-track area at each relative observation angle based on the wave modulation spectrum of the along-track area; Under the same sea surface conditions, the speckle noise spectrum of the target along-track area at the target observation angle is determined by the speckle noise spectrum of the along-track area at each relative observation angle, wherein the sea surface conditions include sea surface wind speed and wave significant wave height.

2. The method according to claim 1, characterized in that Under the same sea surface conditions, the speckle noise spectrum of the along-track area at the target observation angle is the same as the speckle noise spectrum of the target along-track area; When the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum in the along-track area remains unchanged; The speckle noise spectrum of the non-along-track area is the same as the speckle noise spectrum of the boundary area.

3. The method according to claim 1 or 2, characterized in that Before determining the boundary speckle noise spectrum between the along-track area and the non-along-track area by using the speckle noise spectrum of the non-along-track area when the along-track direction is perpendicular to the wave propagation direction, the method further comprises: Under the sea condition of a single wave component, wave fluctuation spectrum samples within the preset sea surface conditions and within the preset wave direction angle range are selected as the non-along-track area speckle noise spectrum.

4. The method according to claim 1 or 2, characterized in that Determining the wave modulation spectrum of the along-track area corresponding to the relative observation angle by using the boundary speckle noise spectrum includes: Determining boundary wave modulation spectra of the along-track area and the non-along-track area through the boundary speckle noise spectrum; The wave modulation spectrum of the along-track area is determined by the boundary wave modulation spectrum.

5. The method according to claim 1 or 2, characterized in that The determining, by using the wave modulation spectrum of the along-track area, the speckle noise spectrum of the along-track area at each relative observation angle comprises: Obtaining a wave spectrum of the along-track area at the corresponding relative observation angle; The wave modulation spectrum of the along-track area is removed from the wave fluctuation spectrum at each relative observation angle in the along-track area to obtain a speckle noise spectrum at each relative observation angle in the along-track area.

6. The method according to claim 1 or 2, characterized in that The speckle noise spectrum of the along-track area at each relative observation angle is obtained by the following formula: Where k represents the wave number, represents the relative observation angle used to divide the along-track area and the non-along-track area, represents any observation angle under the relative observation angles, The relative observation angle is The boundary speckle noise spectrum when represents the speckle noise spectrum in the non-along-track area, The relative observation angle is The boundary wave spectrum between the trackside area and the non-trackside area is: The relative observation angle is The boundary wave modulation spectrum between the along-track area and the non-along-track area is: The relative observation angle is The wave modulation spectrum of the area along the track is The relative observation angle is The wave spectrum of the area along the track is: The relative observation angle is The wave modulation spectrum of the area along the track, P IR (k) represents the wave impulse response spectrum, The relative observation angle is The speckle noise spectrum of the along-track area is shown in FIG.

7. A device for extracting speckle noise spectrum in an along-track area, characterized in that: include: The first determination module is configured to determine the boundary speckle noise spectrum of the along-track area and the non-along-track area based on the speckle noise spectrum of the non-along-track area when the along-track direction is perpendicular to the wave propagation direction; A second determining module is configured to determine, by using the boundary speckle noise spectrum, an ocean wave modulation spectrum of the along-track area corresponding to a relative observation angle; a third determining module, configured to determine a speckle noise spectrum of the along-track area at each relative observation angle based on the wave modulation spectrum of the along-track area; The fourth determination module is used to determine the speckle noise spectrum of the target along-track area at the target observation angle through the speckle noise spectrum of the along-track area at each relative observation angle under the same sea surface conditions, wherein the sea surface conditions include sea surface wind speed and wave effective wave height.

8. The device according to claim 7, characterized in that Under the same sea surface conditions, the speckle noise spectrum of the along-track area at the target observation angle is the same as the speckle noise spectrum of the target along-track area; When the along-track direction is perpendicular to the wave propagation direction, the wave modulation spectrum in the along-track area remains unchanged; The speckle noise spectrum of the non-along-track area is the same as the speckle noise spectrum of the boundary area.

9. An electronic device, characterized in that: include: 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 of the method according to any one of claims 1 to 6 are executed.

10. A computer-readable storage medium, characterized in that include: A computer program, when running on a computer, causes the computer to perform the method according to any one of claims 1 to 6.

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