Hyperspectral imaging equipment for UAVs with geometric scan line stabilization and synchronization with navigation data

Description

[0001] This utility model relates to onboard hyperspectral imaging equipment for unmanned aerial vehicles (UAVs), designed to obtain spatially and spectrally consistent images of the Earth's surface and objects of observation while the vehicle is in motion. The device can be used for remote monitoring, environmental control, mapping, and automated object recognition.

[0002] A hyperspectral camera is known from the prior art (patent for utility model RU No. 1 229 845), based on the Offner circuit, containing an objective, an electronics module, a slit diaphragm, a diffraction grating and a spectral unit, characterized in that the camera has a block structure and includes a cover unit with the cover itself, a lens unit with an objective and an electronics module, a slit diaphragm unit, a diffraction grating unit, a spectral unit, brackets for fastening to the apparatus and a connector for connecting thermal and end sensors, wherein the diffraction grating unit contains a housing in which a cylinder with an external thread is installed by means of a threaded connection with the possibility of axial movement, forming a radial mount, and in turn a diffraction grating and a diffraction grating mirror are installed in it, a stepper motor with a gear transmission is also installed in this unit,wherein the cylinder with the external thread of the diffraction grating is connected to the mounting cylinder of the main mirror of the spectral unit by means of a threaded connection, the main mirror of the spectral unit itself is installed in the mounting cylinder of the spectral unit through a collar with an external thread, which is also installed with the possibility of axial movement due to a stepper motor with a gear transmission installed in the spectral unit, forming a radial mount, wherein the optical circuit of the device itself includes two main lenses installed in the front part of the objective, two small lenses, the main mirror and a small mirror installed in the rear part of the objective, a slit diaphragm, a mirror of the diffraction grating and the main mirror of the spectrometer.

[0003] Also known are hyperspectral line-scanning systems that generate a hyperspectral data cube based on the carrier's motion. Data quality depends on flight stability, speed, roll, pitch, and yaw, as well as the accuracy of temporal and spatial synchronization between frames, navigation data, and inertial measurements.

[0004] Disadvantages of known solutions:

[0005] Geometric distortions when changing the speed and angular position of the UAV;

[0006] Offset of hyperspectral image lines relative to the route;

[0007] Deterioration of spatial alignment of spectral channels;

[0008] The need for complex subsequent geometric correction;

[0009] Data quality deterioration due to vibration, wind gusts and UAV maneuvers.

[0010] Technical task

[0011] Development of hyperspectral imaging equipment for UAVs with geometric stabilization of the scanning line and synchronization with navigation data, which allows for the reduction of geometric distortions and the provision of accurate spatial referencing of hyperspectral data without additional complex correction.

[0012] The solution to the technical problem is achieved in that the hyperspectral imaging equipment for an unmanned aerial vehicle comprises a housing, a lens, an entrance slit, a spectral unit, a photoreceiving module, a control and data processing module, a memory unit, an interface for exchanging with the on-board system of the UAV and a mounting unit, characterized in that it additionally comprises an inertial navigation module, an optical axis angular position sensor, a line of sight stabilization unit made in the form of a lens micro-suspension or a rotating mirror, and a scan line synchronizer, wherein the inertial navigation module, the angular position sensor, the line of sight stabilization unit, the photoreceiving module and the line synchronizer are connected to the control and data processing module, and the scan line synchronizer is configured to assign each line of the hyperspectral image a timestamp, coordinates, altitude,speed and angular position of the unmanned aerial vehicle,

[0013] Technical result

[0014] Reduced geometric distortion, improved accuracy of spatial referencing of scan lines, reduced image blurring, improved object recognition accuracy, improved comparability of data from different flights, improved quality of hyperspectral cube for subsequent processing and mapping.

[0015] Hyperspectral imaging equipment for UAVs contains:

[0016] housing with vibration-isolated mount to minimize the transmission of mechanical vibrations;

[0017] lens with adjustable aperture and focal length;

[0018] entrance slit for forming an optical line;

[0019] spectral unit with a dispersing element (for example, a diffraction grating), collimating and focusing elements;

[0020] Photoreceiving module with high sensitivity matrix;

[0021] control and data processing module with the ability to communicate with the UAV onboard system;

[0022] memory unit and data exchange interface with UAV;

[0023] Carrier mounting unit;

[0024] Inertial navigation module that records the coordinates, speed, roll, pitch and yaw of the UAV;

[0025] optical axis angular position sensor;

[0026] line of sight stabilization unit, made in the form of a micro-suspension of the lens or a rotating mirror;

[0027] Scan line synchronizer, connected to the photoreceiving module, control module and inertial navigation module, ensuring that each line is assigned a timestamp and UAV position parameters.

[0028] By using the structural connection of the optical block, photoreceiving module and navigation module, high accuracy of the formation of the hyperspectral cube and spatial referencing of scanning lines is achieved.

[0029] Before flight, the control module activates the inertial navigation module and the line-of-sight stabilization unit. During flight, the inertial navigation module continuously records the UAV's motion parameters: coordinates, altitude, speed, roll, pitch, and yaw. The optical axis angular position sensor monitors deviations of the line of sight.

[0030] The line-of-sight stabilization unit compensates for optical axis deviations using a lens micro-gimbal or a rotating mirror, ensuring a stable line-of-sight orientation toward the ground surface. At the same time, the scan line synchronizer assigns a timestamp and UAV position parameters, including roll, pitch, yaw, altitude, and speed, to each line of the hyperspectral image.

[0031] All data from the photoreceiver module, navigation module, and inertial unit are fed to the control and data processing module, which generates a corrected hyperspectral cube. The control module synchronizes the data lines with the navigation data in real time, minimizing geometric distortions, ensuring precise spatial alignment of spectral channels, and preparing the data for automated recognition and mapping.

[0032] During flight, the control module periodically checks the synchronization accuracy and, if necessary, adjusts the micro-gimbal or mirror assembly to compensate for changes in the speed and angular position of the UAV, which ensures the stability of the hyperspectral image during maneuvers and vibrations of the carrier.

[0033] Execution example

[0034] The equipment is mounted on the UAV using a vibration-isolated mount. Before flight, the control module and inertial navigation module calibrate the sensors. During flight, the stabilization unit micro-suspenses the lens, compensating for roll, pitch, and yaw, while the line synchronizer assigns timestamps and UAV position parameters to each line of the hyperspectral image. The result is a precise hyperspectral cube suitable for mapping and automated object recognition.

Claims

Hyperspectral imaging equipment for an unmanned aerial vehicle, comprising a housing, a lens, an entrance slit, a spectral unit, a photoreceiving module, a control and data processing module, a memory unit, an interface for communicating with the on-board system of the UAV and a mounting unit, characterized in that it additionally comprises an inertial navigation module, an optical axis angular position sensor, a line of sight stabilization unit made in the form of a lens micro-suspension or a rotating mirror, and a scan line synchronizer, wherein the inertial navigation module, the angular position sensor, the line of sight stabilization unit, the photoreceiving module and the line synchronizer are connected to the control and data processing module, and the scan line synchronizer is configured to assign to each line of the hyperspectral image a timestamp, coordinates, altitude, speed and angular position of the unmanned aerial vehicle.