Contactless Body Temperature Screening with Face-Matched Thermal Imaging
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Solution Overview
Problem
Existing temperature measurement systems, both contact and non-contact, face challenges in providing accurate, reliable, and stable body temperature readings, especially in dynamic environments, due to environmental interference, operator dependence, and installation complexities, which are exacerbated at access points like building entrances.
Innovation Solution
A non-contact measurement system comprising an infrared camera and a visible spectrum camera mounted on a gantry, with a processing unit to correlate images, and reference standards for calibration, ensuring accurate temperature readings by focusing on the inner corner of the eye, and minimizing environmental interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handheld infrared temperature monitoring systems are used, then contactless measurement is achieved, but measurement accuracy varies over time due to environmental temperature changes and sensor drift
Solution Approach 1:
The system performs preliminary calibration by capturing an infrared image of a reference object with known temperature before measuring the target subject. This preliminary action establishes baseline parameters that compensate for environmental conditions and sensor characteristics, ensuring accurate subsequent measurements without requiring manual recalibration.
Solution Approach 2:
The system uses a reference object with known temperature to provide feedback for validating and adjusting measurement parameters. By comparing measured values against the known reference temperature, the system can detect and correct drift in sensor characteristics, maintaining measurement accuracy over time.
2Measurement precision
If fixed infrared monitoring systems with external blackbody reference are used, then measurement accuracy is improved, but installation complexity increases
Solution Approach 1:
The reference object serves multiple functions: it provides a known temperature reference for calibration, acts as a validation target for measurement accuracy, and can be integrated into existing system structures. This multi-functionality eliminates the need for separate calibration equipment, simplifying installation while maintaining measurement precision.
Solution Approach 2:
The reference object acts as an intermediary between the infrared sensor and the target subject. By measuring the reference object first, the system establishes calibration parameters that mediate the measurement process, allowing accurate temperature determination of subsequent subjects without direct complex calibration procedures.
3Productivity
If measurements are taken at building entrances with multiple people passing by, then access control monitoring is enabled, but measurement accuracy deteriorates due to thermal interference from other individuals
Solution Approach 1:
The system extracts and isolates the thermal signal of the target subject from the combined thermal environment. By using image processing to identify and focus on specific facial features of the target individual, the system separates the subject's temperature signal from the thermal interference of surrounding people, enabling accurate measurement despite high throughput.
Solution Approach 2:
The system measures temperature at specific localized regions of the face (such as the inner eye corner) rather than averaging over the entire face or field of view. This localized measurement approach focuses on areas less affected by environmental exposure and surrounding thermal interference, improving accuracy in high-traffic environments.
4Ease of operation
If handheld infrared systems are used, then portability is achieved, but operator intervention is required for calibration and measurement timing
Solution Approach 1:
The system performs self-calibration by automatically capturing and processing images of the reference object, extracting calibration parameters without operator intervention. The system also automatically triggers measurements based on detected subject presence, eliminating the need for operators to manually time measurements or perform calibration procedures, thus maintaining portability while achieving full automation.
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 provides stable, accurate, and reliable body temperature measurements without operator intervention, reducing environmental disturbances and simplifying installation, by correlating infrared and visible images to determine core body temperature.
Implementation Method 1
an infrared camera (12) configured to produce an electronic image of the individual
Implementation Method 2
a visible spectrum camera (6) configured to produce a visible image of the individual
Implementation Method 3
determine a maximum temperature value (Tmax) associated with the infrared image pixels identified in step S4
Data Source
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AI summary
The present invention relates to a system for measuring the body temperature of an individual comprising: a gantry (11) delimiting a passage channel (9) for an individual; a visible spectrum camera (6) fixed on the gantry (11) such that a visual field (31) of the visible spectrum camera (6) covers at least a portion of the passage channel (9); an infrared camera (12) fixed on the gantry (11) such that a visual field (32) of the infrared camera (12) covers all or part of the portion of the passage channel (9); and a processing unit (15) configured to identify the pixels corresponding to the face of an individual in the visible image, to determine the corresponding pixels in the electronic image and to determine a maximum temperature value associated with the pixels corresponding to the face in order to deduce a body temperature of the individual.