On-Orbit RPC Calibration for Segmented Linear-Array Camera Splicing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional geometric calibration methods for spaceborne segmented linear-array cameras are complex and non-uniform, requiring intricate RPM construction and diverse satellite-specific models, making them difficult to implement and standardize.
Innovation Solution
A robust on-orbit geometric calibration method using a rational polynomial coefficient (RPC) model, which includes stepwise absolute and relative calibration to correct geometric distortions, eliminating gross errors and compensating for bias field-of-view distortions, allowing for standardized geometric processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional RPM-based geometric calibration is used, then geometric calibration accuracy is maintained, but the process complexity and difficulty of implementation increase significantly
Solution Approach 1:
The patent extracts the essential geometric calibration function from the complex RPM framework and implements it independently through RPC models. Each CCD segment is calibrated using standalone RPC models that capture the dominant geometric transformations without requiring the full RPM construction process, thereby reducing complexity while maintaining accuracy
Solution Approach 2:
The patent divides the segmented linear-array camera into multiple independent CCD segments, each processed separately with its own RPC model. This segmentation allows each segment to be calibrated independently using simplified models, avoiding the need to process the entire complex system as a unified RPM model
2Measurement precision
If satellite-specific RPM models are constructed for different satellites, then accurate geometric calibration is achieved, but the inability to unify GC across different satellites increases processing complexity
Solution Approach 1:
The patent adopts a universal RPC model framework that can be applied to any segmented linear-array camera regardless of satellite platform. The same RPC-based calibration methodology works across different satellites, orbits, and camera configurations, providing a multi-functional solution that eliminates the need for satellite-specific model development
3Ease of operation
If RPC-based GC is used, then the process is simplified and standardized, but challenges arise in correcting distortion across multiple segmented CCDs
Solution Approach 1:
The patent merges the calibration results from multiple independent CCD segments into a unified geometric correction. By processing each segment with RPC models and then integrating the results through coordinate transformation and splicing, the method achieves both standardized processing and accurate distortion correction across the entire segmented camera system
Data Source
AI summary
A robust on-orbit geometric calibration (GC) method based on the rational polynomial coefficient (RPC) model for spaceborne segmented linear-array camera is proposed. Through a series of processing steps, including obtaining reliable ground control point (GCP) observations based a priori gross error elimination, constructing the adjustment model for GC parameters, GC for absolute geometric distortion, GC for relative geometric distortions among segmented charge-coupled devices (CCDs), and the correction for the created bias field-of-view (FOV) distortion, this invention is able to achieve robust GC for camera distortion, as well as accurate geometric splicing and registration of segmented CCDs under the same geometric benchmark.