A dual-camera joint sea surface aerial photography method and device

Abstract

The main problem solved by the present application is how to simplify the shooting method and image synthesis algorithm between two parallel cameras when flying over the sea. A double-camera joint sea flight method, comprising the following steps: obtaining the earth coordinates of the aircraft, wherein the elevation is converted into altitude; obtaining the altitude of the ground directly below the aircraft according to the earth coordinates of the aircraft; two transverse parallel cameras are installed below the aircraft, and the rotation angle of each camera around the respective visual intersection point is adjusted according to the height difference h between the camera and the sea surface directly below, the visual angle α of each camera, and the distance i between the visual intersection points of the two cameras, so that the visual axis of each camera is adjusted to an angle β=α / 2-arctan(0.5i / h) with the vertical direction, so that the ground area photographed by the two cameras is spliced together in the transverse direction. The beneficial effect is that the shooting method and image synthesis algorithm between the two parallel cameras are simple and easy to implement; there is no mutual overlapping area, and the shooting efficiency is higher.

Description

Technical Field

[0001] This invention relates to the field of aerial photography technology, and in particular to a dual-camera combined aerial photography device and method for the sea surface. Background Technology

[0002] Aerial photography of the sea surface refers to the use of cameras mounted on the underside of an aircraft to photograph the sea surface while the aircraft is in flight.

[0003] With its unique aerial perspective and flexible and efficient operation capabilities, marine aerial photography technology has become a revolutionary tool for applications in many fields.

[0004] In terms of natural landscape documentation and tourism promotion, aerial photography can precisely capture stunning images such as surging waves and sunsets on beaches. Through the creation of high-resolution images and dynamic videos, it injects visual appeal into social media dissemination and tourism promotion. This type of content not only evokes public resonance with the beauty of the ocean but also significantly enhances the brand influence of tourist destinations by showcasing the ecological characteristics of seaside resorts in a panoramic way.

[0005] In the fields of science and environment, drone aerial photography breaks through the spatial and temporal limitations of traditional observation. Equipped with specialized equipment such as multispectral sensors and thermal imagers, researchers can acquire key data in real time, including ocean surface temperature and chlorophyll concentration, while simultaneously tracking environmental events such as red tide spread and oil spill migration. Combined with AI image recognition technology, aerial photography systems can also perform ecological studies such as whale migration trajectory analysis, coral bleaching assessment, and interannual evolution of mangrove wetlands, providing precise data support for marine life conservation and pollution control. Their rapid response capabilities further significantly improve the monitoring efficiency of sudden environmental disasters.

[0006] In commercial applications, aerial photography of the sea demonstrates significant practical value. The real estate industry uses aerial imagery to present the locational advantages and scenic resources of coastal properties in a three-dimensional way, helping clients build an immersive spatial understanding. In the geographic information field, aerial data is used to generate high-precision 3D maps, supporting coastal zone planning and resource management. By integrating multi-source data and intelligent analysis, this technology has evolved into a highly efficient solution connecting nature exploration, scientific research, and business innovation, continuously driving the digital reconstruction of the relationship between humans and the sea.

[0007] The problem is that if the aircraft is at a low altitude above the sea surface, the shooting range is small, and if the aircraft is at a high altitude, the resolution will be reduced. It is difficult for a single camera to achieve both a wide range and high resolution at the same time. In the existing technology, there are solutions for shooting with multiple cameras in parallel, but the shooting methods and image synthesis algorithms between multiple cameras are complex, which affects the shooting effect and efficiency. Summary of the Invention

[0008] The main problem this invention addresses is how to simplify the shooting method and image synthesis algorithm between two parallel cameras for aerial photography over the sea.

[0009] A method for joint aerial photography of the sea surface using dual cameras includes the following steps: Obtain the Earth coordinates of the spacecraft, where elevation is converted to altitude; Based on the Earth coordinates of the spacecraft, obtain the elevation of the ground directly below it; Two horizontally parallel cameras are mounted under the aircraft. Based on the Earth coordinates of the aircraft and the relative position between the cameras and the aircraft, the altitude difference h between the cameras and the sea surface directly below is determined. Each camera can rotate around its respective angle intersection point to adjust the shooting angle. The angle intersection point is the intersection of the horizontal extension lines of the angle of view when each camera is imaging. When each camera is shooting downwards, its respective angle intersection point is located above the camera objective lens. Based on the altitude difference h between the cameras and the sea surface directly below, the angle α of each camera, and the distance i between the two camera angle intersection points, the rotation angle of each camera around its respective angle intersection point is adjusted so that the visual axis of each camera is adjusted to an angle β = α / 2 - arctan(0.5i / h) with the vertical direction, so that the ground area captured by the two cameras is stitched together in the horizontal direction.

[0010] The beneficial effects are that, as long as the viewing axes of each camera are adjusted to the angle with the vertical direction, the ground areas captured by the two cameras are stitched together in the horizontal direction, making the shooting method and image synthesis algorithm of the two parallel cameras simple and easy to implement when taking aerial photos of the sea. Since the ground areas captured by the two cameras are directly stitched together in the horizontal direction without overlapping areas, the overall shooting range of the two cameras is larger and the shooting efficiency is higher. When the aircraft is at a large altitude above the sea surface, because there are two cameras shooting side by side and they can be stitched together to form a complete photo or video, it is possible to achieve both large range and high resolution at the same time, and to quickly capture high-resolution photos of the sea surface. The angle intersection point is the intersection of the backward extensions of the horizontal viewing angles when each camera is imaging. No matter how the camera angle is adjusted, the position of the angle intersection point and the relative position of the two angle intersection points remain unchanged, ensuring the simplicity and reliability of the algorithm. In addition, the reason why this invention can accurately achieve the stitching of images from each camera at an altitude of h is that the sea surface is flat and the height of the sea surface is basically determined, and the calculation can be strictly based on planar and geometric relationships, resulting in high accuracy. According to Baidu Encyclopedia, an aircraft is a device that flies within or outside the atmosphere (space). The aircraft described in this invention mainly refers to those that fly within the atmosphere, such as balloons, airplanes (including drones), etc. The specific aircraft can be selected according to the actual situation.

[0011] Each camera uses a fixed-focus lens, and the intersection point of the viewing angles of each camera is fixed.

[0012] The beneficial effect is that it takes into account the influence of camera size, and at the same time makes the rotation center point of each camera very accurate, strictly conforming to the calculation formula, thus ensuring the accuracy of the calculation results. A fixed-focus lens is a lens with a fixed focal length. Since all cameras use fixed-focus lenses, their viewing angles are fixed. Therefore, the intersection of the backward extensions of the viewing angles of each camera is fixed in position, which makes it easier to install the camera position and calculate accurately.

[0013] The point of intersection of the viewing angles is located on the optical axis of the lens. Let the focal length of the lens be f, and the point of intersection of the camera's viewing angles be located at a distance f from the camera image sensor toward the lens.

[0014] The beneficial effect is that the intersection point of the viewing angles, which is also the optical center point of the lens, is accurately located, ensuring that the calculations strictly follow the formula. The specific positions of the intersection points of the viewing angles of each camera can be determined through experiments or based on relevant camera parameters.

[0015] The images captured by the two cameras are stretched horizontally by a factor of [cosβ+sinβ*cot(π / 2-α / 2-β)].

[0016] The beneficial effect is that, since the cameras on both sides are shooting at an angle, the width of their images is smaller than the actual width of the ground. In order to match the coordinates of each point on the image with the coordinates on the ground, the images captured by the two cameras are stretched in the horizontal direction.

[0017] The image stretching from the two cameras is based on the stitching line of the images; the image from the left camera is stretched to the left, and the image from the right camera is stretched to the right.

[0018] The beneficial effects are that it ensures accurate stitching of images captured by the two cameras, matches the coordinates of each point in the image with those on the ground, and the operation and algorithm are very simple. The only drawback is that the horizontal resolution of the image decreases slightly due to horizontal stretching, but the stretching ratio is usually small, and the decrease in horizontal resolution is minimal, so it has virtually no impact on the overall aerial photography effect over the sea.

[0019] After the aircraft flies a certain distance, the camera below it takes another picture, so that the ground area captured by the two pictures can be perfectly stitched together in the longitudinal direction.

[0020] The beneficial effect is that this allows for the creation of continuous aerial images along the flight path.

[0021] The camera is recording video.

[0022] The beneficial effect is that, similar to the principle of horizontal image stitching, videos can also be stitched horizontally, and large-scale, high-resolution videos can also be captured.

[0023] A dual-camera combined aerial photography device for the sea surface is characterized by comprising an angle adjustment module, a rotating shaft, and two cameras mounted horizontally side-by-side beneath the aircraft. Based on the Earth coordinates of the aircraft and the relative position between the cameras and the aircraft, the altitude difference h between the cameras and the sea surface directly below is determined. Each camera can rotate around its respective viewing angle intersection point to adjust the shooting angle. The viewing angle intersection point is the intersection of the horizontally extended lines of the reverse perspective when each camera is imaging. When each camera is shooting downwards, its respective viewing angle intersection point is located above the camera's objective lens. Based on the altitude difference h between the cameras and the sea surface directly below, the viewing angle α of each camera, and the distance i between the two cameras' viewing angle intersection points, a rotating shaft is provided at the viewing angle intersection point. The angle adjustment module enables the cameras to rotate around the rotating shaft, thereby adjusting the rotation angle of each camera around its respective viewing angle intersection point. When the viewing axes of each camera are adjusted to an angle β = α / 2 - arctan(0.5i / h) with the vertical direction, the ground areas captured by the two cameras are combined horizontally.

[0024] The beneficial effects are that, as long as the viewing axes of each camera are adjusted to the angle with the vertical direction, the ground areas captured by the two cameras are stitched together in the horizontal direction, making the shooting method and image synthesis algorithm of the two parallel cameras simple and easy to implement when taking aerial photos of the sea. Since the ground areas captured by the two cameras are directly stitched together in the horizontal direction without overlapping areas, the overall shooting range of the two cameras is larger and the shooting efficiency is higher. When the aircraft is at a large altitude above the sea surface, because there are two cameras shooting side by side and they can be stitched together to form a complete photo or video, it is possible to achieve both large range and high resolution at the same time, and to quickly capture high-resolution photos of the sea surface. The angle intersection point is the intersection of the backward extensions of the horizontal viewing angles when each camera is imaging. No matter how the camera angle is adjusted, the position of the angle intersection point and the relative position of the two angle intersection points remain unchanged, ensuring the simplicity and reliability of the algorithm. In addition, the reason why this invention can accurately achieve the stitching of images from each camera at an altitude of h is that the sea surface is flat and the height of the sea surface is basically determined, and the calculation can be strictly based on planar and geometric relationships, resulting in high accuracy.

[0025] Each camera uses a fixed-focus lens, and the intersection point of the viewing angles of each camera is fixed.

[0026] The beneficial effect is that it takes into account the influence of camera size, and at the same time makes the rotation center point of each camera very accurate, strictly conforming to the calculation formula, thus ensuring the accuracy of the calculation results. A fixed-focus lens is a lens with a fixed focal length. Since all cameras use fixed-focus lenses, their viewing angles are fixed. Therefore, the intersection of the backward extensions of the viewing angles of each camera is fixed in position, which makes it easier to install the camera position and calculate accurately. Attached Figure Description

[0027] Figure 1 A schematic diagram of a dual-camera combined aerial photography device for the sea surface; Figure 2 Schematic diagram of camera installation structure; Figure 3 A schematic diagram of the shooting principle of a dual-camera combined aerial photography device for the sea surface (the center O is the location of the rotation axis of one camera, that is, the point where the viewpoints intersect). Figure 4 .Diagram of the camera location; Figure 5 Calculation principle diagram.

[0028] In the image: 1. Aircraft, 2. Camera, 3. Rotating shaft, 21. Lens, 22. Image sensor. Detailed Implementation

[0029] Example

[0030] As shown in 1-5, a dual-camera combined aerial photography method for the sea surface includes the following steps: Obtain the Earth coordinates of the spacecraft, where elevation is converted to altitude; Based on the Earth coordinates of the spacecraft, obtain the elevation of the ground directly below it; Two horizontally parallel cameras are mounted under the aircraft. Based on the Earth coordinates of the aircraft and the relative position between the cameras and the aircraft, the altitude difference h between the cameras and the sea surface directly below is determined. Each camera can rotate around its respective angle intersection point to adjust the shooting angle. The angle intersection point is the intersection of the horizontal extension lines of the angle of view when each camera is imaging. When each camera is shooting downwards, its respective angle intersection point is located above the camera objective lens. Based on the altitude difference h between the cameras and the sea surface directly below, the angle α of each camera, and the distance i between the two camera angle intersection points, the rotation angle of each camera around its respective angle intersection point is adjusted so that the visual axis of each camera is adjusted to an angle β = α / 2 - arctan(0.5i / h) with the vertical direction, so that the ground area captured by the two cameras is stitched together in the horizontal direction.

[0031] Specific calculations are as follows: Figure 5As shown, OD is the vertical line passing through point O, OE is the angle bisector of ∠AOB, ∠AOD = arctan(0.5i / h), β = ∠AOE - ∠AOD = α / 2 - arctan(0.5i / h).

[0032] Each camera uses a fixed-focus lens, and the intersection point of the viewing angles of each camera is fixed.

[0033] The point of intersection of the viewing angles is located on the optical axis of the lens. Let the focal length of the lens be f, and the point of intersection of the camera's viewing angles be located at a distance f from the camera image sensor toward the lens.

[0034] The images captured by the two cameras are stretched horizontally by a factor of [cosβ+sinβ*cot(π / 2-α / 2-β)].

[0035] Specific calculations are as follows: Figure 5 As shown, in triangle ABC, ∠ABC=π / 2-α / 2-β, ∠ACB=π / 2+α / 2, ∠CAB=β, AB=AC*cos∠CAB+AC*sinβ*cot∠ABC= AB=AC*[ cosβ+sinβ*cot (π / 2-α / 2-β)].

[0036] The image stretching from the two cameras is based on the stitching line of the images; the image from the left camera is stretched to the left, and the image from the right camera is stretched to the right.

[0037] After the aircraft flies a certain distance, the camera below it takes another picture, so that the ground area captured by the two pictures can be perfectly stitched together in the longitudinal direction.

[0038] The camera is recording video. Example

[0039] As shown in Figures 1-5, a dual-camera combined aerial photography device for the sea surface is characterized by including an angle adjustment module, a rotating shaft, and two cameras. The two cameras are horizontally mounted side by side under the aircraft. Based on the Earth coordinates of the aircraft and the relative position between the cameras and the aircraft, the altitude difference h between the cameras and the sea surface directly below them is determined. Each camera can rotate around its respective viewing angle intersection point to adjust the shooting angle. The viewing angle intersection point is the intersection of the horizontal extension lines of the viewing angles of each camera when it is imaging. When each camera is shooting downwards, its respective viewing angle intersection point is located above the camera lens. Based on the altitude difference h between the cameras and the sea surface directly below them, the viewing angle α of each camera, and the distance i between the viewing angle intersection points of the two cameras, a rotating shaft is set at the viewing angle intersection point. The angle adjustment module enables the cameras to rotate around the rotating shaft, thereby adjusting the rotation angle of each camera around its respective viewing angle intersection point. When the viewing axis of each camera is adjusted to an angle β = α / 2 - arctan(0.5i / h) with the vertical direction, the ground areas captured by the two cameras are combined in the horizontal direction.

[0040] The specific algorithm is as follows: Figure 5 As shown, OD is the vertical line passing through point O, OE is the angle bisector of ∠AOB, ∠AOD = arctan(0.5i / h), β = ∠AOE - ∠AOD = α / 2 - arctan(0.5i / h).

[0041] Each camera uses a fixed-focus lens, and the intersection point of the viewing angles of each camera is fixed.

Claims

1. A method for joint aerial photography of the sea surface using dual cameras, comprising the following steps: Obtain the Earth coordinates of the spacecraft, where elevation is converted to altitude; Based on the Earth coordinates of the spacecraft, obtain the elevation of the ground directly below it; Two horizontally parallel cameras are mounted under the aircraft. Based on the Earth coordinates of the aircraft and the relative position between the cameras and the aircraft, the altitude difference h between the cameras and the sea surface directly below is determined. Each camera can rotate around its respective angle intersection point to adjust the shooting angle. The angle intersection point is the intersection of the horizontal extension lines of the angle of view when each camera is imaging. When each camera is shooting downwards, its respective angle intersection point is located above the camera objective lens. Based on the altitude difference h between the cameras and the sea surface directly below, the angle α of each camera, and the distance i between the two camera angle intersection points, the rotation angle of each camera around its respective angle intersection point is adjusted so that the visual axis of each camera is adjusted to an angle β = α / 2 - arctan(0.5i / h) with the vertical direction, so that the ground area captured by the two cameras is stitched together in the horizontal direction.

2. The method for joint aerial photography of the sea surface using dual cameras according to claim 1, characterized in that, Each camera uses a fixed-focus lens, and the intersection point of the viewing angles of each camera is fixed.

3. The method for joint aerial photography of the sea surface using dual cameras according to claim 2, characterized in that, The point of intersection of the viewing angles is located on the optical axis of the lens. Let the focal length of the lens be f, and the point of intersection of the camera's viewing angles be located at a distance f from the camera image sensor toward the lens.

4. A method for joint aerial photography of the sea surface using dual cameras according to claim 1, characterized in that, The images captured by the two cameras are stretched horizontally by a factor of [cosβ+sinβ*cot(π / 2-α / 2-β)].

5. The method for joint aerial photography of the sea surface using dual cameras according to claim 4, characterized in that, The image stretching from the two cameras is based on the stitching line of the images; the image from the left camera is stretched to the left, and the image from the right camera is stretched to the right.

6. The method for joint aerial photography of the sea surface using dual cameras according to claim 1, characterized in that, After the aircraft flies a certain distance, the camera below it takes another picture, so that the ground area captured by the two pictures can be perfectly stitched together in the longitudinal direction.

7. The method for joint aerial photography of the sea surface using dual cameras according to claim 1, characterized in that, The camera is recording video.

8. A dual-camera combined aerial photography device for the sea surface, characterized in that, The system includes an angle adjustment module, a rotating shaft, and two cameras mounted horizontally side-by-side beneath the aircraft. Based on the aircraft's Earth coordinates and the relative positions of the cameras, the altitude difference *h* between the cameras and the sea surface directly below is determined. Each camera can rotate around its respective viewing angle intersection point to adjust its shooting angle. This intersection point is the point where the horizontal extensions of the viewing angles of each camera intersect. When each camera shoots downwards, its respective viewing angle intersection point is located above the camera's objective lens. Based on the altitude difference *h* between the cameras and the sea surface directly below, the viewing angle *α* of each camera, and the distance *i* between the two cameras' viewing angle intersection points, a rotating shaft is installed at the intersection point. The angle adjustment module allows the cameras to rotate around this shaft, thereby adjusting the rotation angle of each camera around its respective viewing angle intersection point. When the viewing axes of each camera are adjusted to an angle *β* = *α / 2* - *arctan(0.5i / h)* with the vertical direction, the ground areas captured by the two cameras are combined horizontally.

9. A dual-camera combined marine aerial photography device according to claim 8, characterized in that, Each camera uses a fixed-focus lens, and the intersection point of the viewing angles of each camera is fixed.

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