Tri-Field IR Imaging System with Removable Afocal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing passive IR imaging systems face challenges in achieving a large field of view while maintaining sensitivity and cost-effectiveness, as reducing the focal length to increase the field of view leads to sensitivity degradation, and existing scanning methods are insufficient for automatic detection algorithms.
Innovation Solution
A dual-field optical device coupled with a scanning platform and a back-scanning device, using a removable afocal and counter-scanning mirror to achieve a tri-field imaging system with a 30° x 30° field, allowing for a 90° horizontal field coverage with a single IR detector and maintaining constant entrance pupil size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the focal length is reduced to increase the field of view, then the field of view is improved, but the sensitivity of the system is degraded
Solution Approach 1:
The patent employs a variable focal length optical system that can dynamically adjust between different focal lengths. The optical device includes a first optical system for small field of view and a second optical system for large field of view, allowing the system to adapt its focal length based on operational requirements. This dynamic adjustment enables the system to maintain sensitivity when needed while achieving panoramic coverage when required.
Solution Approach 2:
The optical system is segmented into multiple independent optical subsystems: a first optical system optimized for small field of view (2°-4°) and a second optical system optimized for large field of view (30°-90°). Each subsystem has its own optical path and can be selectively activated. This segmentation allows the system to maintain optimal sensitivity for each function while providing both capabilities through a single integrated device.
2Productivity
If scanning speed is increased to achieve sufficient scanning rate for automatic detection algorithms, then the productivity is improved, but the integration time of the detector is exceeded
Solution Approach 1:
The patent uses a dual optical system that enables rapid switching between narrow and wide fields of view. The second optical system with its large field of view (30°-90°) allows the system to achieve panoramic coverage without requiring extremely fast scanning, as the wider angle reduces the number of scan positions needed. This dynamic field adjustment helps maintain scanning rates above 0.5 Hz while respecting detector integration time constraints.
3Ease of manufacture
If a single detector is used to limit cost, then the manufacturing cost is reduced, but the device complexity increases to achieve multi-field functionality
Solution Approach 1:
The patent designs a universal optical device that performs multiple functions through a single integrated structure. The device includes a first optical system for small field detection and a second optical system for panoramic observation, both sharing common components such as the detector, housing, and control electronics. This multi-functional design allows a single detector to serve both PC and GC modes, reducing overall system cost while managing complexity through shared architecture.
Solution Approach 2:
The optical device is segmented into functionally independent but physically integrated subsystems. The first optical system (for small field) and second optical system (for large field) are distinct optical paths that can be selectively activated. This segmentation allows each subsystem to be optimized for its specific function while sharing common support infrastructure, thereby controlling overall complexity while enabling multi-field operation with a single detector.
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 recognition, identification, and detection with a compact system capable of scanning at a sufficient rate for operational targets, maintaining sensitivity and reducing the size of the entrance window, while supporting a larger field of view without sensitivity loss.
Implementation Method 1
a back-scanning device making it possible to stabilize the image during the shooting
Implementation Method 2
a removable afocal of determined magnification G placed upstream of the forming means of image
Implementation Method 3
an IR matrix detector, a two-field optical device, capable of forming an image on the detector
Data Source
Figure 1a~1c
Figure 2~3
Figure 4a~4c
AI summary
The invention concerns an IR passive imagery system (200) including: an IR matrix detector (10), - a two-field optical device, capable of forming an image on the detector and including image formation methods on an optical axis (20'), a removable afocal (30) of determined G magnification placed upstream of the image formation methods, an aperture diaphragm (40) placed between the detector and the image formation methods. It includes scanning methods (70') in the directional angle of the detective assembly and two-field optical device, since the aperture diaphragm (40) is removable and the optical device includes, in addition, a blockable backflushing mirror (81), arranged upstream of the image formation methods, and the image formation methods include methods for obtaining a third field, the backflushing mirror (81) and the methods for obtaining a third field being arranged on said optical axis and capable of forming an image on said detector (10) with the goal of obtaining a three-field imaging system.