Radiometric Calibration of Infrared Detector Using Movable Mirror
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Solution Overview
Problem
Conventional calibration systems for imaging detectors in space-based devices are cumbersome due to size and weight constraints, making regular recalibration challenging and unserviceable, especially in environments where size and weight impact the overall assembly and launch costs, and require complex systems that are not easily maintainable.
Innovation Solution
A calibration system using a movable mirror and a fixed mirror to selectively image multiple blackbody sources onto an infrared focal plane array, allowing for radiometric calibration with a compact and serviceable mechanism that can be easily integrated into the optical path for periodic recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex calibration system is used to ensure accurate radiometric calibration, then measurement precision is improved, but device complexity and weight increase
Solution Approach 1:
The patent combines multiple calibration functions into a single integrated optical path. The movable mirror serves dual purposes: it both inserts the calibration source into the optical path and selects between multiple blackbody sources. The fixed mirror simultaneously performs imaging of the selected blackbody source onto the detector, eliminating the need for separate insertion and selection mechanisms.
Solution Approach 2:
The movable mirror is designed as a multi-functional element that performs both the insertion of calibration sources and the selection between multiple blackbody sources. The fixed mirror provides universal imaging capability for all blackbody sources onto the detector, allowing a single calibration mechanism to serve multiple calibration functions.
2Measurement precision
If a complex calibration system is used to ensure accurate radiometric calibration, then measurement precision is improved, but weight increases
Solution Approach 1:
The patent combines multiple calibration functions into a single integrated optical path. The movable mirror serves dual purposes: it both inserts the calibration source into the optical path and selects between multiple blackbody sources. The fixed mirror simultaneously performs imaging of the selected blackbody source onto the detector, eliminating the need for separate insertion and selection mechanisms.
Solution Approach 2:
The movable mirror is designed as a multi-functional element that performs both the insertion of calibration sources and the selection between multiple blackbody sources. The fixed mirror provides universal imaging capability for all blackbody sources onto the detector, allowing a single calibration mechanism to serve multiple calibration functions.
3Measurement precision
If a complex calibration system is used to ensure accurate radiometric calibration, then measurement precision is improved, but ease of repair deteriorates
Solution Approach 1:
The calibration system is segmented into distinct functional modules: a movable mirror for source insertion and selection, a fixed mirror for imaging, and multiple blackbody sources. This modular segmentation allows individual components to be independently serviced, replaced, or adjusted without affecting the entire calibration system, significantly improving ease of repair.
Solution Approach 2:
The calibration system is designed to be self-contained and self-servicing. The movable and fixed mirrors are positioned within the optical path to allow for easy access and adjustment. The blackbody sources are independently controllable, allowing the system to perform self-diagnosis and self-calibration without requiring external service intervention for routine maintenance.
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 efficient and accurate recalibration of imaging systems with reduced size and weight, allowing for precise correction of pixel-to-pixel variations and changes over time, while maintaining the system's operational integrity and reducing maintenance complexity.
Implementation Method 1
a primary optical element to reflect the collected energy
Implementation Method 2
a secondary optical element to reflect energy from the primary optical element to the sensor
Implementation Method 3
a movable first mirror configured to be selectively inserted into the optical path between the secondary optical element and an intermediate image during calibration
Implementation Method 4
first and second calibration energy sources
Data Source
AI summary
Methods and apparatus for sensor calibration of a system having an aperture, primary mirror, secondary mirror, and a sensor, such as an FPA IR sensor. A calibration system includes calibration energy sources with a movable first mirror configured to be selectively inserted into the optical path and select one of the calibration energy sources and a second mirror configured to image the selected calibration energy source.