Thermal Imaging Accuracy via Reference Calibration
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Solution Overview
Problem
Current thermal imaging systems are inadequate for accurately detecting elevated core body temperatures due to insufficient detectability, lack of accurate reference targets, and failure to correct for environmental and physiological effects, leading to unreliable fever detection.
Innovation Solution
A temperature detection system incorporating a thermal imaging system, a reference illumination system, and a data correction system that includes shutter-based nonuniformity correction, gain uniformization, and temperature conversion to provide accurate temperature measurements, while also accounting for ambient and physiological corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a highly uniform thermal image sensor with accuracy of ±0.5°C is used, then measurement precision is improved, but device complexity and cost increase due to requirement for cooled sensors
Solution Approach 1:
A reference illumination source is introduced as an intermediary element to provide a known thermal reference that can be captured by the thermal image sensor. This reference target with known temperature and high uniformity allows the system to calibrate and correct measurements, enabling accurate temperature detection without requiring the sensor itself to have high intrinsic uniformity and accuracy
Solution Approach 2:
The system changes the parameters of the measurement approach by using a reference target with known temperature characteristics rather than relying solely on the sensor's intrinsic accuracy. By capturing images of the reference target at known temperatures and using these to establish calibration curves, the system transforms the measurement problem from one requiring high-precision sensors to one solvable through reference-based calibration
2Measurement precision
If a reference illumination source is added to improve accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The reference illumination source serves as a mediator that bridges the gap between the thermal image sensor and the target object. By providing a known thermal reference that can be captured alongside or instead of the target, it enables calibration and correction of sensor measurements without requiring complex sensor modifications
Solution Approach 2:
The reference illumination source is used to perform preliminary calibration actions before actual temperature measurements are taken. By capturing images of the reference target at known temperatures and establishing calibration curves in advance, the system prepares the measurement parameters beforehand, simplifying the actual measurement process
3Productivity
If thermal imaging systems are used for fever detection, then productivity is improved through non-contact measurement, but reliability deteriorates due to inability to accurately detect temperatures around 100.4°F
Solution Approach 1:
The system uses the reference illumination source to provide feedback for calibration. By continuously or periodically capturing images of the reference target with known temperature and comparing these against expected values, the system can detect and correct drift or inaccuracies in the thermal image sensor, maintaining reliable fever detection capability
Solution Approach 2:
The reference target acts as an intermediary standard that enables the system to verify and calibrate its measurements against a known reference. This allows the system to maintain accuracy for detecting fevers at 100.4°F while preserving the rapid non-contact measurement capability
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 system achieves accurate temperature measurements with a precision of ±0.5°C, enabling reliable detection of fevers around 100.4°F, reducing false positives, and improving the reliability of thermal imaging in healthcare settings.
Implementation Method 1
Thermal imaging devices detect radiation emitted by objects by sensing infrared photons and identifying the flux thereof
Implementation Method 2
The reference illumination system includes at least one reference calibration unit that is visible to the thermal imaging system
Data Source
AI summary
A temperature detection system includes a housing, a thermal imaging system at least partially disposed within the housing, and a data correction system communicatively coupled with the thermal imaging system. The thermal imaging system is configured to capture at least one thermal image of a subject. The data correction system is configured to correct at least one error associated with the at least one thermal image of the subject.