Wide multi-angle visible light laser active and passive integrated aerial survey load

Abstract

The invention relates to a wide-width multi-angle visible light laser active and passive integrated aerial survey load. The load comprises a visible light imaging module, a near-infrared imaging module, a laser radar, a positioning and attitude determining system (POS) and a camera body supporting structure. Wherein the passive imaging module comprises a visible light imaging module and a near-infrared imaging module, the visible light imaging module is formed by splicing three cameras, and wide images are synchronously obtained in single flight. The laser radar is an active imaging module, and obtains a large amount of laser point cloud data by actively emitting laser. The laser radar module and the wide imaging module are systematically integrated, the laser radar, the visible light camera and the near-infrared camera work cooperatively under the condition that the field of view is overlapped, laser point cloud data can effectively compensate for image elevation errors, the problem of accuracy loss caused by single-dimensional splicing is solved, multiple application modes are achieved, and the application range is wide. And large-area terrain, landform and urban landscape information can be efficiently obtained.

Description

Technical Field

[0001] This invention belongs to the field of airborne optoelectronic imaging and surveying technology, specifically relating to a wide-swath, multi-angle visible light laser active and passive integrated airborne surveying payload. Background Technology

[0002] The development trend of aerial mapping payloads is to balance large coverage area with high imaging accuracy to meet the needs of efficient and high-precision data acquisition. Currently, there are two main approaches: One approach is the ultra-large format 2D stitching system, which expands simultaneously along both the flight path and lateral directions using multi-lens 2D stitching. This increases the image size to achieve wide coverage and a higher datum-to-height ratio, resulting in high-efficiency and high-precision mapping. The other approach is the wide-format single-dimensional imaging system, which only expands the field of view laterally. While maintaining the aerial survey range, this reduces system complexity, payload size, and weight, significantly lowering implementation difficulty and cost. Payload products using the 2D stitching approach for ultra-large format imaging suffer from system complexity, large size, and weight, making them unsuitable for small and medium-sized UAV platforms. While the single-dimensional stitching wide-format imaging approach simplifies payload composition, it compresses the imaging range along the flight path, reducing the datum-to-height ratio and causing a decrease in elevation accuracy, only meeting the planar accuracy requirements of mapping.

[0003] Currently, domestic lidar technology is becoming increasingly mature. Due to its rapid data acquisition capabilities, non-contact nature, and penetrating power, it is widely used in fields such as digital power grids, urban 3D modeling, and forestry. Combining a large field-of-view lidar with a wide-swath imaging system can simultaneously acquire imagery and ground 3D information, effectively compensating for the loss of elevation accuracy caused by swath compression. Therefore, there is an urgent need for an integrated active and passive aerial survey payload to simultaneously acquire high-precision imagery and 3D data. Summary of the Invention

[0004] The purpose of this invention is to provide a wide-swath, multi-angle visible light laser active and passive integrated aerial survey payload system. It adopts the synergy of multi-angle visible light camera stitching, near-infrared imaging and wide field of view lidar, which can solve the problem of elevation accuracy loss caused by swath compression, while achieving lightweight design and efficient coordination of multiple payloads.

[0005] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions: A wide-swath, multi-angle visible light laser active-passive integrated aerial survey payload includes a visible light imaging module, a near-infrared imaging module, a lidar, a POS system, and a camera main support structure. A visible light imaging module for acquiring visible light images includes three imaging systems, each including a visible light camera lens and a color digital back. Near-infrared imaging module for acquiring near-infrared images, including near-infrared camera lens (14) and black-and-white digital back; LiDAR is used to measure the distance between an object and a sensor. The POS system is used for attitude determination and positioning, and to achieve time synchronization between the visible light imaging module, the near-infrared imaging module, and the lidar. The main camera support structure supports the visible light imaging module, near-infrared imaging module, lidar, and POS system.

[0006] The visible light imaging module includes a first visible light camera lens, a second visible light camera lens, a third visible light camera lens, a first color digital back, a second color digital back, and a third color digital back; the first visible light camera lens and the first color digital back, the second visible light camera lens and the second color digital back, and the third visible light camera lens and the third color digital back respectively form three imaging systems.

[0007] The second visible light camera lens and the second color digital back are the main imaging system and image at an angle perpendicular to the ground. The other two imaging systems are set on both sides of the main imaging system. The optical axes of the near-infrared camera lens and the second visible light camera lens are parallel.

[0008] The lidar is installed along the flight direction, and the scanning direction is perpendicular to the flight direction.

[0009] The positioning coordinate axis of the POS system is parallel to the optical axis of the main camera.

[0010] The three visible light imaging systems have the same parameters. The focal plane stitching direction of the three visible light imaging systems is perpendicular to the flight direction. The side field of view of the near-infrared camera lens and the field of view of the lidar are the same as the side field of view of the three imaging systems after stitching.

[0011] The overlap range of the visible light camera array image plane is not less than 5% of the image plane, and the total width after stitching is not less than 40,000 pixels.

[0012] The near-infrared camera lens has a wavelength range of 760nm-890nm, and its field of view covers the field of view of three visible light cameras stitched together.

[0013] The laser radar has a wavelength of 1450~1650nm, a scanning field of view of 70~80°, and can cover the field of view of three visible light cameras stitched together.

[0014] It also includes an electronic control unit, through which the visible light imaging module, near-infrared imaging module, lidar and POS system (4) are controlled and operated.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: (1) This invention fuses lidar point cloud data with visible light images to directly compensate for elevation errors and solve the problem of accuracy loss caused by single-dimensional stitching.

[0016] (2) The present invention uses three high-resolution cameras to stitch together to achieve simultaneous acquisition of wide-angle images and three-dimensional point cloud data in a single flight.

[0017] (3) The lidar of this invention works in collaboration with visible light and near-infrared cameras when the fields of view overlap, which can effectively improve the fusion accuracy of elevation data and image data. It has multiple application modes and can efficiently acquire large-area terrain, landform and urban landscape information.

[0018] (4) Compared with the two-dimensional matrix large-area array imaging system, the present invention effectively reduces the system complexity, reduces the product size and weight, and forms a compact, efficient and high-precision integrated aerial survey payload solution that is suitable for small and medium-sized UAV platforms. Attached Figure Description

[0019] Figure 1 This is a block diagram of the load system of the present invention; Figure 2 This is a schematic diagram of a wide-span integrated primary and secondary aerial survey payload system according to the present invention; Figure 3 This is a schematic diagram of the visible light lens focal plane splicing of the present invention; Figure 4 This is a schematic diagram of the active and passive imaging of the present invention; Figure 5 This is a schematic diagram of focal plane splicing in an embodiment of the present invention. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: A wide-swath, multi-angle visible light laser active-passive integrated aerial survey payload system, such as Figure 1 As shown, it consists of two parts: the camera body and the camera control system. The camera body includes a camera body support structure 5, a visible light imaging module, a near-infrared imaging module, a lidar 3, and a POS system 4. The camera control system mainly includes an electronic control unit.

[0021] like Figure 2 As shown, the visible light imaging module includes a first visible light camera lens 11, a second visible light camera lens 12, a third visible light camera lens 13, a first color digital back 21, a second color digital back 22, and a third color digital back 23; the near-infrared imaging module includes a near-infrared camera lens 14 and a black and white digital back 24.

[0022] The first visible light camera lens 11, the second visible light camera lens 12, and the third visible light camera lens 13 have the same optical parameters and form three independent optical systems with the first color digital back 21, the second color digital back 22, and the third color digital back 23, respectively. Among them, the second visible light camera lens 12 and the second color digital back 22 are the main imaging systems, which image at an angle perpendicular to the ground. The other two imaging systems are mounted on the camera body support structure 5 at a fixed installation intersection angle with the main camera.

[0023] The optical axes of the near-infrared camera lens 14 and the second visible light camera lens 12 are parallel, and they are mounted on the camera body support structure 5 along with the black and white digital back 24.

[0024] The lidar 3 has the function of actively emitting a laser beam and measuring its return time to accurately calculate the distance between the object and the sensor. The lidar 3 is installed on the camera main support structure 5 along the flight direction, and the scanning direction is perpendicular to the flight direction.

[0025] The POS system 4 consists of an inertial measurement unit (IMU) and a GPS antenna. It has the functions of attitude determination and positioning, as well as time synchronization between three visible light cameras, near-infrared cameras and lidar 3. It is fixed on the camera main support structure 5, and the positioning coordinate axis is parallel to the optical axis of the main camera.

[0026] The diagram shows the effect of stitching together three visible light cameras. Figure 3 As shown, the focal plane splicing direction is perpendicular to the flight direction.

[0027] The lateral (perpendicular to the flight direction) field of view of the near-infrared camera and the field of view of the lidar are the same as the lateral field of view of the large-format camera after stitching together, such as Figure 4 As shown.

[0028] Each payload of the camera system is connected to the system control electronics unit to enable functions such as power supply and synchronous control of multiple payloads, ensuring efficient and coordinated operation of the camera and other components.

[0029] The overlap range of the visible light camera array image plane is not less than 5% of the image plane, and the total width after stitching is not less than 40,000 pixels.

[0030] The near-infrared camera has a wavelength range of 760nm-890nm, and its field of view covers the field of view of three visible light cameras stitched together.

[0031] The laser radar has a wavelength of 1550±100nm, a scanning direction perpendicular to the flight direction, and a scanning field of view of 70~80° that can cover the field of view of the optical system.

[0032] The load system is integrated as follows: Step (1): Assembly of Visible Light / Near Infrared Camera First, the three visible light lenses are integrated with the color digital back to achieve optical focus, and then assembled into three sets of visible light imaging systems with identical parameters. The near-infrared camera lens 14, paired with a near-infrared filter (760nm-890nm), is integrated with the monochrome digital back 24 to achieve optical focus.

[0033] Step (2): Installation of Visible Light / Near Infrared Cameras One of the three assembled visible light imaging systems is selected as the main camera and mounted on the camera's main support structure 5. The main camera's optical axis is calibrated to be perpendicular to the flight direction. The other two visible light imaging systems are mounted on the support, forming a certain intersection angle with the main camera's optical axis, ensuring that the plane formed by the main optical axes of the three visible light cameras coincides. At the same time, a near-infrared camera is mounted on the camera's main support structure 5, with its optical axis parallel to the optical axis of the main camera in the visible light imaging system. The near-infrared camera's field of view covers the stitched field of view of the three visible light cameras.

[0034] Step (3): LiDAR Integration The lidar 3 is mounted onto the camera main support structure 5, aligning the main optical axis of the lidar 3 with that of the main camera, and ensuring that the scanning direction of the lidar 3 coincides with the plane formed by the main optical axes of the three cameras. The scanning field of view of the lidar 3 is consistent with the combined field of view of the three visible light cameras.

[0035] Step (4): POS System Integration The POS system 4 is installed on the camera main support structure 5, with the X-axis of the device pointing to the flight direction of the camera system, that is, perpendicular to the plane formed by the principal optical axis; the Y-axis of the device pointing to the right of the flight direction of the camera system, located on the plane formed by the principal optical axis; and the Z-axis of the device pointing to the main imaging direction of the camera, located on the plane formed by the principal optical axis.

[0036] Step (5): Installation of the system electronics control unit The camera system controls and operates each payload through a control electronics unit, including independent / cooperative operation of each payload, enabling operation modes in various application scenarios.

[0037] Example Step (1): Assembly of Visible Light / Near Infrared Camera like Figure 5As shown, a 110mm focal length visible light lens is integrated with a 14000×11000 pixel (3.76μm pixel size) color digital back to achieve optical fixed focus, forming three sets of visible light imaging systems with identical parameters. The near-infrared camera lens has a 32mm focal length and is paired with a near-infrared filter (760nm-890nm) and integrated with a 14000×11000 pixel (3.76μm pixel size) monochrome digital back to achieve optical fixed focus.

[0038] Step (2): Installation of Visible Light / Near Infrared Cameras One of the three assembled visible light imaging systems was selected as the main camera and mounted on the main support structure of the camera system. The optical axis of the main camera was calibrated to be perpendicular to the flight direction. The other two visible light imaging systems were then mounted on the support structure, ensuring that the planes formed by the main optical axes of the three visible light cameras coincided. The intersection angle between the optical axes of the other two visible light cameras and the main camera was within the range of 27.0°±1°, and the overlap of their fields of view with the main camera was 2.6°. After the cameras were stitched together, as shown... Figure 5 As shown, considering a load operating height of 1000m, the overlap pixels after stitching are 1300 (accounting for 10%), the total frame size is 40000 pixels, and the equivalent field of view of the stitched virtual frame size is 75.0°. Simultaneously, a near-infrared camera is mounted on the camera system bracket, with its optical axis parallel to the optical axis of the main camera of the visible light imaging system. The field of view of the near-infrared camera covers the stitched field of view of the three visible light cameras.

[0039] Step (3): LiDAR Integration A 1550nm wavelength lidar (detection range: 1000m @p≥20%) is mounted on support structure 5, aligning its principal optical axis with that of the main camera. The lidar's scanning direction should coincide with the plane formed by the principal optical axes of the three cameras. The lidar's scanning field of view is consistent with the stitched field of view of the three visible light cameras.

[0040] Step (4): POS System Integration The POS system is mounted on the main support structure of the camera, with the X-axis pointing in the direction of flight of the camera system, that is, perpendicular to the plane formed by the principal optical axis; the Y-axis pointing to the right of the direction of flight of the camera system, located on the plane formed by the principal optical axis; and the Z-axis pointing in the main imaging direction of the camera, located on the plane formed by the principal optical axis.

[0041] Step (5): Installation of the system electronics control unit The camera system controls and operates each payload through a control electronics unit, including independent / cooperative operation of each payload, enabling operation modes in various application scenarios.

[0042] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0043] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A wide-swath, multi-angle visible light laser active / passive integrated aerial survey payload, characterized in that: It comprises a visible light imaging module, a near-infrared imaging module, a laser radar (3), a POS system (4) and a camera body support structure (5), wherein, The visible light imaging module realizes wide-width visible light imaging through splicing and comprises three groups of imaging systems with the same optical parameters, each group of imaging system being composed of a visible light camera lens and a color digital back; The near-infrared imaging module is used for acquiring near-infrared images and comprises a near-infrared camera lens (14) and a black digital back (24); The laser radar (3) is used for emitting laser and receiving echoes to acquire three-dimensional point cloud data; The POS system (4) is used for positioning and orientation and realizing time synchronization among the visible light imaging module, the near-infrared imaging module and the laser radar (3); The camera body support structure (5) is used for mounting and fixing the visible light imaging module, the near-infrared imaging module, the laser radar (3) and the POS system (4).

2. The wide-width multi-angle visible laser active-passive integrated photogrammetry payload according to claim 1, characterized in that: The visible light imaging module comprises a first visible light camera lens (11), a second visible light camera lens (12), a third visible light camera lens (13), a first color digital back (21), a second color digital back (22) and a third color digital back (23); the first visible light camera lens (11), the second visible light camera lens (12) and the third visible light camera lens (13) and the first color digital back (21), the second color digital back (22) and the third color digital back (23) respectively form three imaging systems. 3.The wide swath multi-angle visible laser active-passive integrated photogrammetry payload according to claim 1, characterized in that: The second visible light camera lens (12) and the second color digital back (22) are the main imaging system and image at an angle perpendicular to the ground, and the other two imaging systems are arranged on both sides of the main imaging system; the three imaging systems have the same parameters, and the splicing direction of the focal plane is perpendicular to the flight direction.

4. The wide swath multi-angle visible laser active-passive integrated photogrammetry payload according to claim 1, characterized in that: The laser radar (3) is installed along the flight direction, the scanning direction is perpendicular to the flight direction, and the scanning field of view angle can cover the field of view of the three visible light cameras after splicing.

5. The wide swath multi-angle visible laser active-passive integrated photogrammetry payload according to claim 1, characterized in that: The positioning coordinate axis of the POS system (4) is parallel to the main camera optical axis.

6. The wide swath multi-angle visible laser active-passive integrated photogrammetric payload according to claim 1, characterized in that: The visible light camera array image surface overlap range is not less than 5% of the image surface, and the total width after splicing is greater than twice of the single imaging system.

7. The wide swath multi-angle visible laser active-passive integrated photogrammetric payload according to claim 1, characterized in that: The optical axis of the near-infrared camera lens (14) and the second visible light camera lens (12) is parallel, the wavelength range of the near-infrared camera lens (14) is 760nm-890nm, and the lateral field of view angle covers the field of view of the three visible light cameras after splicing.

8. The wide swath multi-angle visible laser active-passive integrated photogrammetric payload according to claim 1, characterized in that: It further comprises an electronic control unit, and the visible light imaging module, the near-infrared imaging module, the laser radar (3) and the POS system (4) are controlled and operated through the electronic control unit.

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