Thermally Isolated Hot Stop Aperture for Accurate Thermal Imaging
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Solution Overview
Problem
Thermal imaging systems face bias in recorded temperature due to external thermal energy entering the camera when the optical field of view exceeds the camera's view, especially in environments where apertures cannot be substantially cooled, leading to transient temperature variations that affect imaging accuracy.
Innovation Solution
A hot stop aperture fixture is introduced, comprising a hot aperture and a cold aperture thermally isolated by a thermal isolation block, with separate heat sinks to stabilize the apertures' temperatures, minimizing bias effects through controlled thermal exchange and active compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide optical field of view is used to capture more target information, then the measurement coverage is improved, but external thermal energy enters the camera causing temperature bias
Solution Approach 1:
An aperture stop is introduced as an intermediary component between the target and the camera. This aperture stop has a cold surface that blocks external thermal energy from entering the camera while allowing optical information to pass through, thus mediating between the need for wide field of view and the need to prevent thermal contamination
Solution Approach 2:
The harmful thermal energy is extracted and blocked by the cold aperture stop surface, which selectively removes external thermal radiation from the optical path while preserving the target's thermal information that needs to be captured by the camera
2Device complexity
If the aperture is not substantially cooled, then the device complexity is reduced, but transient temperature variations affect imaging accuracy
Solution Approach 1:
The aperture stop is pre-cooled to a stable temperature before use, establishing a cold reference state in advance. This preliminary cooling action creates a stable thermal baseline that prevents transient temperature variations from affecting the imaging accuracy, without requiring continuous complex cooling systems during operation
3Device complexity
If external thermal energy enters the camera, then the device structure is simplified, but bias is introduced in the recorded temperature
Solution Approach 1:
The aperture stop serves as a simple intermediary component that introduces minimal structural complexity while effectively blocking external thermal energy. It provides a straightforward solution that prevents temperature bias without requiring complex active cooling or filtering systems
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
The hot stop aperture fixture stabilizes the cold aperture temperature, reducing bias and enhancing imaging accuracy by maintaining a consistent 'cold stop' temperature, allowing for effective characterization and compensation of transient thermal variations.
Implementation Method 1
The hot stop assembly includes a hot aperture having a first surface configured to face the target and a second surface configured to face an interior portion of the hot stop assembly. The hot stop assembly also includes a cold aperture having a first surface configured to face the camera and a second surface configured to face the interior portion of the hot stop assembly. The hot aperture is thermally isolated from the cold aperture.
Implementation Method 2
manipulating thermal radiation from the target before the thermal radiation reaches the camera using an optical assembly disposed between the camera and the target
Data Source
AI summary
A system includes a camera configured to detect thermal radiation emitted from a target. The system also includes an optical assembly configured to be disposed between the camera and the target. The system further includes a hot stop assembly disposed between the camera and the optical assembly. The hot stop assembly includes a hot aperture having a first surface configured to face the target and a second surface configured to face an interior portion of the hot stop assembly. The hot stop assembly also includes a cold aperture having a first surface configured to face the camera and a second surface configured to face the interior portion of the hot stop assembly. The hot aperture is thermally isolated from the cold aperture and reduces transient temperature changes from the environment on the images.