PCB Blackbody Calibration Source for Human-Temperature Thermal Imaging
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Solution Overview
Problem
Existing mass producible thermal imaging devices struggle to accurately determine temperatures within the narrow range of human body temperatures, separating normal from fever, due to limitations in performance and manufacturing tolerances.
Innovation Solution
A cost-effective, field-deployable temperature-controlled calibration source is provided, utilizing a PCB-based blackbody calibration source with a heat conductive layer and resistive heater, powered by common power sources, to maintain a uniform temperature for precise thermal camera calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mass producible thermal imaging devices are used, then cost is reduced and production volume increases, but measurement precision deteriorates in narrow temperature ranges
Solution Approach 1:
The system performs preliminary calibration by capturing a reference image of a blackbody source at a known temperature before measuring the target. This preliminary action establishes a baseline that compensates for manufacturing variations in the thermal imaging device, enabling accurate temperature measurements in narrow ranges despite mass production tolerances.
Solution Approach 2:
The system changes the temperature parameter of the blackbody calibration source to match the expected target temperature range. By adjusting the calibration source temperature to be close to the measurement target temperature, the system optimizes the calibration effectiveness for that specific temperature range, improving measurement precision without sacrificing mass producibility.
2Adaptability or versatility
If conventional thermal imaging processes are used, then general applicability is maintained, but accuracy deteriorates in specific narrow temperature ranges
Solution Approach 1:
The system applies local quality by using a blackbody calibration source with a specific emissivity coating (e.g., matte black paint with emissivity ≥0.95) tailored for the narrow temperature range of interest. This localized optimization of the calibration source properties enhances measurement accuracy in the specific temperature range while maintaining the overall versatility of the thermal imaging device for other applications.
Solution Approach 2:
The system performs a preliminary calibration step using a blackbody source at a known temperature before actual measurements. This preliminary action captures a reference image that accounts for device-specific characteristics, enabling accurate measurements in narrow temperature ranges while preserving the device's general applicability through a reusable calibration approach.
3Ease of operation
If field deployable calibration sources are used, then ease of operation improves, but device complexity increases
Solution Approach 1:
The system uses a simple, inexpensive blackbody calibration source that can be deployed in the field without requiring complex infrastructure. The calibration source is designed to be portable and self-contained, accepting trade-offs in long-term durability for ease of deployment and operation. The simplicity of the calibration source design reduces device complexity while maintaining field deployability.
Solution Approach 2:
The system performs self-calibration by using an onboard blackbody source that can be activated independently to capture reference images. This self-service capability eliminates the need for external calibration equipment or complex setup procedures, improving ease of operation in the field while keeping the overall device complexity manageable through integration.
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 accurate temperature measurements within a few degrees of human body temperature, enhancing the performance of low-cost thermal imaging devices for fever detection applications.
Implementation Method 1
a resistive heater spanning a heated region is disposed on a first side of the PCB
Implementation Method 2
a heat conductive layer spanning at least a portion of the heated region is disposed on the at least one copper layer of the PCB opposite the resistive heater
Implementation Method 3
An even temperature-controlled blackbody calibration source for thermal camera calibration may be provided
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
A temperature controlled calibration source for thermal imaging that provides for extremely inexpensive, mass producible, field deployable thermal calibration in specific, relatively low temperature ranges, and in particular temperatures near nominal human body temperature. A calibration source suitable for such applications may be implemented primarily as a suitable designed Printed Circuit Board (PCB), packaged in a thermally isolating housing and powered of commonly available power sources such as USB chargers.