CN114877898A - Sun dynamic tracking method based on underwater polarization attitude and refraction coupling inversion - Google Patents
Sun dynamic tracking method based on underwater polarization attitude and refraction coupling inversion Download PDFInfo
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Abstract
The invention relates to a solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion. Firstly, an underwater polarization angle image is calculated by utilizing a polarized light intensity image acquired by an underwater polarization sensor, and an imaging pixel in a Snell window is determined by combining a horizontal attitude angle; then calculating an underwater refraction angle of light rays entering the underwater polarization sensor by using the two horizontal attitude angles, converting an underwater polarization angle image in a Snell window into an atmosphere 8-shaped polarization angle image, further extracting a solar meridian from the atmospheric 8-shaped polarization angle image, and dividing the atmospheric 8-shaped polarization angle image into two regions by taking the atmospheric meridian as a boundary; and finally, solving the sun vector by respectively utilizing the polarization E-vector and the polarization degree of the atmosphere solved by the pixels of the two regions. The invention considers the attitude dynamic change information of the carrier and expands the application scene of the sun tracking method based on polarized light in the underwater Snell window.
Description
Technical Field
The invention belongs to the field of underwater autonomous navigation, and particularly relates to a solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion.
Background
The bionic polarized light navigation is a novel navigation means inspired by the behavior of determining the self course by sensing atmospheric polarized light by insects, has the advantages of complete autonomy, no error accumulation and the like, has been widely researched in the atmospheric environment at present, and the research of applying the polarized light navigation to underwater is still in the starting stage. The polarized light can provide navigation information because it contains sun information, so the basic idea of polarized light navigation is to solve the position of the sun through the acquired polarization information, and then realize navigation capability through the sun.
Solving the position of the sun based on polarized light is a precondition for realizing navigation by utilizing the polarized light. The Chinese patent CN201410652332.8 of the invention utilizes the atmospheric polarization distribution mode to resolve the position of the sun by a cluster analysis method; the Chinese patent of invention CN201710027484.2 utilizes the polarization E-vector of the atmosphere to establish the optimal estimation array of the sun vector to solve the sun position information; the chinese invention patent CN201810592616.0 proposes a sun position calculating method based on atmospheric polarization degree. However, in an underwater environment, in the process of transmitting polarized light from the atmosphere into water, a refraction phenomenon occurs on the water surface, and the refraction changes the propagation direction of the polarized light and the deflection of a polarization plane, so that the above method for calculating the sun vector in the atmospheric environment is not suitable for the underwater environment; the chinese invention patent CN201911252040.4 proposes a sun tracking method based on polarized light in an underwater snell window, which compensates the effect of refraction on polarized light, but is only applicable to the application scenario of a horizontal static base, and cannot be applied to the scenario of dynamic attitude change. When dynamic change of the attitude exists, the imaging position of the snell window in the image also changes, and the image identification-based method is utilized, the invention patent CN202011307276.6 in china proposes a method for identifying the edge in the image to extract the snell window, but the image processing algorithm has a large calculation amount and cannot be applied to real-time calculation of an underwater dynamic scene.
Different from the atmospheric environment, the sun tracking method based on the underwater polarized light field has obvious difference in two scenes, namely the dynamic change of the carrier attitude in the underwater environment and the horizontal static base. The water surface refraction phenomenon occurs under a navigation coordinate system, and the compensation of the refraction action needs to calculate the horizontal posture first to obtain information such as a refraction angle. Therefore, dynamic coupling of attitude and refraction phenomena exists in the underwater environment, which seriously affects the solar dynamic tracking precision based on the underwater polarized light field. Quantification and compensation of refraction in dynamic change of carrier attitude are key problems for improving applicability of dynamic application scenes of the sun tracking method.
Disclosure of Invention
In order to solve the technical problem, the invention provides a solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion, two horizontal attitude angles of a pitch angle and a roll angle are introduced to determine the imaging position of a Snell window and the refraction angle of light in the observation direction in the window, thereby compensating the influence of light bending and polarization plane deflection caused by refraction and realizing the solar dynamic tracking under the attitude/refraction coupling action. Furthermore, the polarization degree reflects the quality of polarized light, and the polarization degree is introduced as the weight of each polarization E vector, so that the robustness of solar dynamic tracking can be improved. The invention combines the attitude information of the carrier, and inverts the refraction polarization light distribution mode in the underwater Snell window obtained under any attitude to obtain the polarization E-vector of the atmosphere by dynamic compensation of the refraction action on the water surface, thereby calculating the sun vector.
The technical scheme adopted by the invention for solving the technical problems is as follows: the solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion comprises the following implementation steps:
step (1), obtaining a polarized light intensity image by using an underwater polarization sensorP k （kFor analyzing the polarization direction) to calculate an underwater polarization angle image I, and combining the underwater polarization angle image I with a pitch angleθAnd roll angleγDetermining imaging pixels in a Snell window by the two horizontal attitude angles;
step (2) calculating the underwater refraction angle of the light entering the underwater polarization sensor by using the two horizontal attitude anglesrThe polarization angle image I in the underwater Snell window is processed by compensating refraction in Performing inversion calculation to obtain an atmospheric 8-shaped polarization angle image I in8 ；
Step (3), obtaining an atmospheric 8-shaped polarization angle image I in the step (2) in8 Extracting the solar meridian and dividing I by the solar meridian in8 Divided into two regionsp Ⅰ Andp Ⅱ ；
step (4), utilizing the atmospheric 8-shaped polarization angle image I obtained in the step (3) in8 Inp Ⅰ And withp Ⅱ And the pixels of the two regions solve the polarization E-vector and the polarization degree of the atmosphere, and solve the sun vector according to the orthogonal relation of the polarization E-vector and the sun vector of the atmosphere.
Further, the specific steps of step (1) are as follows:
defining a horizontal coordinate system (hSystem), carrier pitch angle and roll angle are respectivelyθAndγthen the carrier coordinate system (bSystem) andhthe coordinate transformation matrix between the systems is represented as:
coordinates of each pixel in underwater polarization angle image I (m,n) In thatbObservation vector under systeml b Inverted from the camera lens model Θ:
l b =Θ(m,n)
then the observation vector is inhIs represented as follows:
if it ishObservation vector under systeml h Underwater angle of refraction of directionally incident lightrIn an azimuth ofφThen, thenl h Can be expressed as:
l h = [cosφsinr sinφsinr cosr] T
angle of refractionrIs acute angle, and has sine value of
. Whereinl h Is represented byl h The first element of (1). Known from Snell's law of refraction, the angle of refraction underwaterrThe relationship between the angle of incidence of the light ray is:
wherein the content of the first and second substances,n a andn w respectively representing the refractive indices in the atmosphere and in water,iis the angle of incidence of the light. When in usei<At 90 deg., the incident ray can be refracted. The sine function is a monotone decreasing function in the acute angle range, so that the refraction angle in the Snell windowrThe requirements are satisfied:
then, the underwater polarization angle image I is satisfied
The pixel is judged to be in the Snell window, and the underwater Snell window polarization angle image I is obtained in 。
Further, the specific steps of the step (2) are as follows:
polarization angle image I in underwater snell window in The value of each pixel is the included angle between the polarization E-vector of the atmosphere in the observation direction of the point and the zero position of the imageαWherein, in the step (A),
. The observation vector of the pixel obtained in the step (1) isl h Then, thenl h The azimuth angle of (A) is:
ϕ=arctan2(l h (2),l h (1))
the underwater "8" polarization azimuth angle χ of the pixel u Comprises the following steps:
χ u =α−ϕ
observation vectorl h Angle of refraction of directionally incident light rays under waterrComprises the following steps:
the angle of incidence of the beam from the atmosphere can be calculated from snell's law of refraction:
whereiniRepresenting the incident angle of the light, since the incident angle of the light is acute, then:
then the "8" polarization azimuth angle χ of the atmospheric incident ray a ：
And simultaneously calculating the propagation vector of the incident light of the atmosphere:
imaging the directional atmospheric incident light directly through the camera lens, imaging pixel coordinates: (m a ,n a ) Comprises the following steps:
wherein the content of the first and second substances,round(. x) denotes rounding operation. Thereby obtainingm a ,n a ) Is a pixel coordinate of χ a Atmospheric "8" polarization angle image I of pixel values in8 。
Further, the specific steps in step (2) are as follows:
atmospheric 8-shaped polarization angle image I calculated in step (2) in8 The atmospheric polarization E-vector of the atmospheric incident polarized light corresponding to each pixel is:
because the E-vector of the atmospheric polarization is perpendicular to the sun vector, the E-vector of the atmospheric polarization on the sun meridian is perpendicular to the sun meridian, and the 8-shaped polarization azimuth angle chi of the atmospheric incident light ray a And the polarization E-vector z-axis azimuth component of the atmosphere on the solar meridian is zero by substituting the formula. Therefore, a threshold value is set according to the actual situationκ,(κ>0) Is selected to satisfy
Is formed by a plurality of pixelsp * As pixels near the solar meridian
Whereine a (3) Representing a vectore a The third element of (1); and fitting the pixels meeting the condition to form a straight linem+kn+b=0, whereinkAndbrespectively, the linear parameters are the atmospheric 8-shaped polarization angle image I in8 The middle solar meridian.
When I is in8 Inner pixel coordinate satisfiesm+kn+b>At 0, the pixel is on one side of the solar meridian, and the set of all pixels in the area is defined asp Ⅰ (ii) a In the same way, when I in8 Inner pixel coordinate satisfiesm+kn+b<At 0, the pixels are on the other side of the solar meridian, and the set of all pixels in the area is defined asp Ⅱ 。
Further, the specific steps of the step (4) are as follows:
obtaining polarized light intensity image by underwater polarization sensorPSolving out images of degree of polarizationDAnd from I to I calculated in step (2) and step (3) in8 By a polarization degree imageDDetermination of I in8 The polarization degree corresponding to each pixel in the image is obtained to obtain an atmospheric polarization degree imageD in8 . The sum vector of the polarization E-vectors respectively constructing the two regional atmospheres is as follows:
wherein the content of the first and second substances,E Ⅰ ，E Ⅱ respectively representing the sum vector of the polarization E-vectors of the two regional atmospheres,
representing images of atmospheric polarization degreeD in8 The middle pixel coordinate is (m a ,n a ) The pixel value of (a), i.e., the degree of polarization;
by the expression I in8 The middle pixel coordinate is (m a ,n a ) Pixel value χ a And solving the calculated atmospheric polarization E-vector of the atmospheric incident polarized light.
Then to solvehSystematic ambiguity sun vectors h′ Comprises the following steps:
taking into account that the sun is above the horizon during the day, the zenith vector is utilized
To resolve the ambiguity, the final sun vector is as follows:
whereinsign(v) represents the sign of v, from which the solution is derivedhIs the lower sun vector.
Has the advantages that:
compared with the prior art, the invention has the following advantages: the existing sun tracking method based on underwater polarized light is only suitable for a horizontal static base scene. According to the solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion, pixels in a Snell window in polarization imaging are dynamically selected through the acquired horizontal attitude angle, the effect of refraction on atmospheric incident polarized light is dynamically compensated, the polarization degree is introduced to serve as the atmospheric polarization E-vector weight, and the precision and robustness of solar dynamic tracking are improved.
Drawings
FIG. 1 is a flow chart of a solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion according to the present invention;
FIG. 2 is a schematic diagram of a coordinate system and refraction according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person skilled in the art based on the embodiments of the present invention belong to the protection scope of the present invention without creative efforts.
According to an embodiment of the present invention, as shown in fig. 1, the solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion of the present invention includes the following steps:
step 1, obtaining a polarized light intensity image by using an underwater polarization sensorP k Solving underwater polarization angle imageICombined with carrier pitch angleθAnd roll angleγThe two horizontal attitude angles determine the imaging pixels within the snell window, wherekIs the polarization detection direction. The method comprises the following specific steps:
in this embodiment, taking a four-channel underwater polarization sensor as an example, the four-channel polarization detection directions are respectively 0 °,45 °,90 ° and 135 °, so that the underwater polarization sensor obtains the polarized light intensity imageP 0 ,P 45 ,P 90 ,P 135 From this, the underwater polarization angle image I can be calculated as:
defining a horizontal coordinate system (hSystem), carrier pitch angle and roll angle are respectivelyθAndγthen the carrier coordinate system (bSystem) andhthe coordinate transformation matrix between the systems is represented as:
coordinates of each pixel in underwater polarization angle image I (m,n) In thatbObservation vector under systeml b Inverted from the camera lens model Θ:
l b =Θ(m,n)
then the observation vector is inhIs represented as follows:
if it ishObservation vector under systeml h The angle of refraction of a directionally incident ray under water isrIn an azimuth ofφThen, thenl h Can be expressed as:
l h = [cosφsinr sinφsinr cosr] T
angle of refractionrIs acute angle, and has sine value of
。
Angle of refraction known from Snell's law of refractionrAngle of incidence to lightiThe relationship between them is:
wherein the content of the first and second substances,n a andn w respectively representing the refractive indices in the atmosphere and in water,iis the angle of incidence of the light.
When in usei<At 90 deg., the light is refracted. The sine function is a monotone decreasing function in the acute angle range, so the refraction angle in the Snell windowrThe requirements are satisfied:
then, it is satisfied in the underwater polarization angle image I
The pixel is judged to be in the Snell window, and the polarization angle image I in the underwater Snell window is obtained in . Whereinl h Is represented byl h The first element of (1).
Step 2, calculating the refraction angle of the light entering the underwater polarization sensor by using the two horizontal attitude anglesrThe polarization angle image I in the underwater Snell window is obtained by compensating refraction in Performing inversion calculation to obtain an atmospheric 8-shaped polarization angle image I in8 . The method comprises the following specific steps:
polarization angle image I in underwater snell window in The value of each pixel is the included angle between the polarized light vibration direction and the image zero position in the observation direction of the pointαWherein, in the step (A),αin the range of
。
The observation vector of the pixel obtained from step 1 isl h Then, thenl h The azimuth angle of (A) is:
ϕ=arctan2(l h (2),l h (1))
the underwater 8-shaped polarization azimuth angle of the pixelχ u Comprises the following steps:
χ u =α−ϕ
observation vectorl h Angle of refraction of directionally incident light rays under waterrComprises the following steps:
the incident angle of the beam of light from the atmosphereiCan be calculated from snell's law of refraction:
whereiniRepresenting the angle of incidence of the light. Since the incident angle of the light is acute, it is obtained:
as shown in FIG. 2, the E-vector of polarization of the atmosphere can be decomposed into two orthogonal components, each perpendicular to the plane of refractione ⊥ And parallel to the refracting surfacese ‖ . When the water surface refraction occurs, the attenuation degrees of the two components are different, and the polarized light is refracted by airInto the water, the two components being represented ast ⊥ Andt ‖ from the fresnel refraction equation:
the following relation exists between the atmospheric and underwater 8-shaped polarization azimuth angles before and after refraction:
then the "8" polarization azimuth angle χ of the atmospheric incident ray a Can be expressed as:
observation vectorl h In an azimuth ofϕThe zenith angle is equal to the refraction anglerThen, thenl h Can be expressed as:
l h = [cosϕsinr sinϕsinr cosr] T
the azimuth angle of the atmospheric incident light before and after refraction is unchanged, and only the zenith angle is changed. The zenith angle of atmospheric incident light is the incident angle of lightiThen, as shown in FIG. 2, the propagation vector of the incident light of the atmospherel a In thathIs represented as
Due to the fact that
Therefore:
imaging the directional atmospheric incident light directly through the camera lens, imaging pixel coordinates: (m a ,n a ) Comprises the following steps:
whereinround(. x) denotes rounding operation. Thereby obtainingm a ,n a ) Is a pixel coordinate of χ a Atmospheric "8" polarization angle image I of pixel values in8 。
Step 3, obtaining an atmospheric 8-shaped polarization angle image I in the step 2 in8 Extracting the solar meridian and dividing I by the solar meridian in8 Divided into two regionsp Ⅰ Andp Ⅱ . The method comprises the following specific steps:
atmospheric 8-shaped polarization angle image I calculated in step 2 in8 Each pixel value in the set of pixel values is the atmospheric polarization E-vector of the atmospheric incident polarized light corresponding to the pixele a In thathIs represented as follows:
e a =v cosχ a +u sinχ a
whereinv,uRespectively represent the tangential unit vector of the meridian direction and the latitude direction of the celestial sphere observation point in the over-atmosphere, and the tangential unit vector is as follows:
v=[cosicosφcosisinφ−sini] T
u=[−sinφcosφ0] T
this gives:
since the E-vector of the atmospheric polarization is perpendicular to the sun vector, the atmospheric polarization lies in the solar meridianThe E-vector is perpendicular to the solar meridian, so that the '8' -shaped polarization azimuth angle of the atmospheric incident lightχ a And the polarization E-vector z-axis azimuth component of the atmosphere on the solar meridian is zero by substituting the formula. Therefore, a threshold value is set according to the actual situationκ,(κ>0) Is selected to satisfy
Is formed by a plurality of pixelsp * As pixels near the solar meridian
Whereine a (3) Representing a vectore a The third element of (1); and fitting the pixels meeting the condition to form a straight linem+kn+b=0, whereinkAndbrespectively, the linear parameters are the atmospheric 8-shaped polarization angle image I in8 The middle solar meridian.
When I is in8 Inner pixel coordinate satisfiesm+kn+b>At 0, the pixel is on one side of the solar meridian, and the set of all pixels in the area is defined asp Ⅰ (ii) a In the same way, when I in8 Inner pixel coordinate satisfiesm+kn+b<At 0, the pixels are on the other side of the solar meridian, and the set of all pixels in the area is defined asp Ⅱ 。
Step 4, utilizing the atmospheric 8-shaped polarization angle image I obtained in the step 3 in8 Inp Ⅰ Andp Ⅱ and the pixels of the two regions solve the polarization E-vector and the polarization degree of the atmosphere, and solve the sun vector according to the orthogonal relation of the polarization E-vector and the sun vector of the atmosphere. The method comprises the following specific steps:
obtaining polarized light intensity image by underwater polarization sensorP k Solving out images of degree of polarizationD：
From I to I calculated in step 2 and step 3 in8 Using polarization degree imagesDDetermination of I in8 Obtaining an atmospheric polarization degree image by the corresponding polarization degree of each pixelD in8 . Then order:
wherein the content of the first and second substances,E Ⅰ ，E Ⅱ respectively representing the sum vector of the polarization E-vectors of the two regional atmospheres,
representing images of atmospheric polarization degreeD in8 The middle pixel coordinate is (m a ,n a ) The pixel value of (a), i.e., the degree of polarization;
by the expression I in8 The middle pixel coordinate is (m a ,n a ) Pixel value χ a And solving the calculated atmospheric polarization E-vector of the atmospheric incident polarized light.
Then to solvehSystematic ambiguity sun vectors h′ Comprises the following steps:
the zenith vector is utilized in view of the fact that the sun is usually above the horizon during the day
To resolve the ambiguity, the final sun vector is as follows:
whereinsign(*)The sign of #is expressed, and then the sign is solvedhIs the lower sun vector.
Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, but various changes may be apparent to those skilled in the art, and it is intended that all inventive concepts utilizing the inventive concepts set forth herein be protected without departing from the spirit and scope of the present invention as defined and limited by the appended claims.
Claims (5)
1. A solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion is characterized by comprising the following steps:
step (1), obtaining a polarized light intensity image by using an underwater polarization sensorP k Calculating underwater polarization angle image I and combining pitch angleθAnd roll angleγThe two horizontal attitude angles determine the imaging pixels within the snell window, wherekIs the direction of polarization analysis;
step (2) calculating the underwater refraction angle of the light entering the underwater polarization sensor by using the two horizontal attitude anglesrThe polarization angle image I in the underwater Snell window is obtained by compensating refraction in Performing inversion calculation to obtain an atmospheric 8-shaped polarization angle image I in8 ；
Step (3), obtaining an atmospheric 8-shaped polarization angle image I in the step (2) in8 Extracting the solar meridian and dividing I by the solar meridian in8 Divided into two regionsp Ⅰ Andp Ⅱ ；
step (4), utilizing the atmospheric 8-shaped polarization angle image I obtained in the step (3) in8 Inp Ⅰ Andp Ⅱ and the pixels of the two regions solve the polarization E-vector and the polarization degree of the atmosphere, and solve the sun vector according to the orthogonal relation of the polarization E-vector and the sun vector of the atmosphere.
2. The solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion of claim 1, characterized in that:
the specific steps of the step (1) are as follows:
defining a horizontal coordinate system, and the pitch angle and the roll angle of the carrier are respectivelyθAndγthen, the coordinate transformation matrix between the carrier coordinate system and the horizontal coordinate system is expressed as:
wherein the horizontal coordinate system ishSystem, carrier coordinate systembIs a step of;
coordinates of each pixel in underwater polarization angle image I (a)m,n) In thatbObservation vector under systeml b Inverted from the camera lens model Θ:
l b =Θ(m,n)
then the observation vector is inhIs represented as follows:
satisfaction in underwater polarization angle image I
The pixel is judged to be in the Snell window, and the polarization angle image I in the underwater Snell window is obtained in (ii) a Whereinl h Is represented byl h The first element of (a) is,n a andn w respectively, the refractive indices in the atmosphere and water.
3. The solar dynamic tracking method based on underwater polarization attitude and refraction coupling inversion of claim 2, characterized in that:
the specific steps of the step (2) are as follows:
polarization angle image I in underwater snell window in The value of each pixel is the included angle between the polarization E-vector of the atmosphere in the observation direction of the point and the zero position of the imageαWherein, in the step (A),αin the range of
；
The observation vector of the imaging pixel obtained in the step (1) isl h The underwater "8" polarization azimuth angle χ of the imaging pixel u Comprises the following steps:
χ u =α−arctan2(l h (2),l h (1))
observation vectorl h Angle of refraction of directionally incident light rays under waterrComprises the following steps:
then the "8" polarization azimuth angle χ of the atmospheric incident ray a Comprises the following steps:
and simultaneously calculating the propagation vector of the incident light of the atmosphere:
imaging the directional atmospheric incident light directly through the camera lens, imaging pixel coordinates: (m a ,n a ) Comprises the following steps:
whereinround(x) represents rounding to the rounding operation;
thereby obtaining (A) am a ,n a ) Is a pixel coordinate of χ a Atmospheric "8" polarization angle image I of pixel values in8 。
4. The method of claim 3 for solar dynamic tracking based on underwater polarization attitude and refraction coupling inversion, characterized in that:
the specific steps of the step (3) are as follows:
atmospheric 8-shaped polarization angle image I calculated in step (2) in8 The atmospheric polarization E-vector of the atmospheric incident polarized light corresponding to each pixel is:
because the E-vector of the atmospheric polarization is perpendicular to the sun vector, the E-vector of the atmospheric polarization on the sun meridian is perpendicular to the sun meridian, and the 8-shaped polarization azimuth angle chi of the atmospheric incident light a The polarization E-vector z-axis azimuth component of the atmosphere on the solar meridian is zero by substituting the formula; therefore, a threshold value is setκ,(κ>0) Is selected to satisfy
Is formed by a plurality of pixelsp * As pixels near the solar meridian
Whereine a (3) Representing a vectore a The third element of (1); and fitting the pixels meeting the conditions to form a straight linem+kn+b=0, whereinkAndbrespectively, the linear parameters are the atmospheric 8-shaped polarization angle image I in8 The solar meridian of middle;
when I is in8 Inner pixel coordinate satisfiesm+kn+b>At 0, the pixel is on one side of the solar meridian, and the set of all pixels in the area is defined asp Ⅰ (ii) a When I is in8 Inner pixel coordinate satisfiesm+kn+b<At 0, the pixels are on the other side of the solar meridian, and the set of all pixels in the area is defined asp Ⅱ 。
5. The method of claim 4 for solar dynamic tracking based on underwater polarization attitude and refraction coupling inversion, characterized in that:
the specific steps of the step (4) are as follows:
obtaining polarized light intensity image by underwater polarization sensorP k Solving out images of degree of polarizationDAnd from I to I calculated in the step (2) and the step (3) in8 By a polarization degree imageDDetermination of I in8 The corresponding polarization degree of each pixel in the image is obtained to obtain an atmospheric polarization degree imageD in8 (ii) a The sum vector of the polarization E-vectors respectively constructing the two regional atmospheres is as follows:
wherein the content of the first and second substances,E Ⅰ ，E Ⅱ respectively representing the sum vector of the polarization E-vectors of the two regional atmospheres,
representing images of atmospheric polarization degreeD in8 The middle pixel coordinate is (m a ,n a ) The pixel value of (a), i.e., the degree of polarization;
by the expression I in8 The middle pixel coordinate is (m a ,n a ) Pixel value χ a Solving the calculated atmospheric polarization E-vector of the atmospheric incident polarized light;
solution tohSystematic ambiguity sun vectors h′ Comprises the following steps:
because the sun is above the horizon in the daytime, the zenith vector is utilized
Disambiguation, the final sun vector is as follows:
whereinsign(v) represents the sign of v, from which the solution is derivedhIs the lower sun vector.
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| CN116222580A (en) * | 2023-05-09 | 2023-06-06 | 北京航空航天大学 | Underwater polarization orientation method based on cross-medium refraction interference compensation correction |
| CN117109594A (en) * | 2023-10-23 | 2023-11-24 | 北京航空航天大学 | Autonomous orientation method based on underwater light intensity gradient |
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