Ground Station Radiometric Correction for Aerial Imagery
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Solution Overview
Problem
Current methods for remotely sensed imagery in agriculture face challenges in calibration and geometric correction, requiring specialized equipment and ground-truthing for radiometric and positional data, which limits the ability to compare imagery across different times and locations, affecting the accuracy of crop health assessments.
Innovation Solution
A ground-based station that combines radiometric readings with light sensors and GPS for post-flight image processing, allowing for remote and automated orthorectification and radiometric correction, reducing the need for on-site personnel and specialized equipment, and enabling accurate GPS coordinates without centimeter-scale accuracy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ground-based stations with light sensors and GPS are used for radiometric correction and orthorectification, then measurement precision and automation are improved, but device complexity increases
Solution Approach 1:
The ground-based station integrates multiple functions into a single device: light sensors for radiometric correction, GPS for positional data, and automated processing capabilities. This multi-functional approach improves measurement precision while managing device complexity through consolidation rather than separate specialized equipment.
Solution Approach 2:
The system performs automated orthorectification and radiometric correction using onboard sensors and processors, eliminating the need for manual ground-truthing by personnel. The station self-calibrates using its own light sensors to measure downwelling and upwelling radiance, and uses GPS for automatic georeferencing.
2Measurement precision
If specialized equipment and ground-truthing are used for radiometric correction, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The ground-based station automatically performs radiometric correction by measuring both downwelling radiance (from sky and sun) and upwelling radiance (from the ground) using its light sensors. This self-calibrating capability eliminates the need for operators to manually deploy specialized equipment or perform complex ground-truthing procedures.
Solution Approach 2:
The system replaces manual mechanical ground-truthing operations with automated electronic sensing and processing. Light sensors electronically measure radiance values, and processors automatically calculate reflectance corrections, substituting complex manual procedures with simpler automated electronic operations.
3Measurement precision
If centimeter-scale GPS accuracy is required for orthorectification, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The system replaces complex high-precision GPS hardware with a simpler GPS receiver combined with ground-based light sensors. The orthorectification is achieved through the integration of GPS positional data with radiometric measurements from the ground station, rather than relying solely on complex GPS positioning systems.
Solution Approach 2:
The ground-based station acts as an intermediary between the aerial imagery and the final orthorectified product. It provides ground truth radiance measurements that mediate the conversion of aerial radiance values to reflectance, while GPS provides positional mediation for georeferencing, reducing the need for centimeter-scale GPS accuracy in the aerial platform.
4Device complexity
If only upwelling radiance is measured without downwelling radiance, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The ground-based station's light sensors are configured to measure both downwelling radiance (from sky and sun) and upwelling radiance (from the ground) using the same hardware platform. This multi-functional sensor configuration enables complete radiometric correction while maintaining device simplicity through unified sensor design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and automated correction of aerial imagery, allowing for remote assessment of crop health and growth, facilitating decision-making for optimal harvest times and enhancing crop yields by providing reliable data for crop management.
Implementation Method 1
measure both downwelling radiance originating from the sky and upwelling radiance incident on the ground within a defined spectral band
Implementation Method 2
reflectance is the ratio of upwelling to downwelling radiation within a defined spectral hand
Implementation Method 3
determining a position of the ground-based station using a global positioning system (GPS)
Data Source
AI summary
The present inventors have developed a ground station that, when installed in a field, can collect upwelling and downwelling radiation, and GPS location coordinates, Data from remotely sensed imagery (RSI) can be used to monitor crop health. Use of the ground station can obviate the need for personnel to be deployed into the field during drone overflights for management of agriculture.