# Comparative study of image quality acquired on a new portable dynamic laboratory test bench using two thermal time constant uncooled IRFPA microbolometric camera

Boualem Merainani, Thibaud Toullier, Jean Dumoulin

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Boualem Merainani, Thibaud Toullier, Jean Dumoulin. Comparative study of image quality acquired on a new portable dynamic laboratory test bench using two thermal time constant uncooled IRFPA microbolometric camera. QIRT Asia 2025 - 5th Quantitative InfraRed Thermography Conference Asia, Jul 2025, Harbin, China. hal-05357087

HAL Id: hal-05357087

https://inria.hal.science/hal-05357087v1

Submitted on 10 Nov 2025

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# Comparative study of image quality acquired on a new portable dynamic laboratory test bench using two thermal time constant uncooled IRFPA microbolometric camera

by B. Merainani*, T. Toullier* and J. Dumoulin*

** Univ. Gustave Eiffel, Inria, COSYS-SII, I4S Team, F-44344, Bouguenais, France, jean.dumoulin@univ-eiffel.fr

## Abstract

An experimental setup dedicated to assessing and comparing the image quality of uncooled IRFPA microbolometer cameras with different thermal time constants has been designed and realized. Initially, we explored a concept involving heated objects mounted on two opposing arms rotating at different temperatures; However, practical constraints, such as the need for electrical brushes to transfer current, as well as significant challenges related to mass balance and installation complexity, made this approach impractical. Consequently, we adopted a new solution comprising fixed thermal panels and a self-designed rotating disk inspired by optical choppers. We designed the test bench to be compact and portable, enhancing its versatility and making it adaptable to various testing environments. Figure 1 illustrates both the CAD design and the real implementation of the test bench.

<figure><img src="image_2.png" /><figcaption>**Fig. 1.** CAD Design and Real Prototype of the Test Bench with Copper Thermal Panels – IR image illustration</figcaption></figure>

The setup employs a high-performance Maxon EC-max 40 brushless motor equipped with Hall sensors, providing accurate speed measurement and precise control. Motor speed is effectively controlled through an ESCON 50/5 servo controller utilizing closed-loop PWM signals generated by an Arduino microcontroller.

To comprehensively evaluate thermal imaging performance across a range of conditions, we integrated two independently heated thermal panels, each powered by Thermofoil polyimide heaters. The rear thermal panels are built with high thermal conductivity material, which ensures rapid and uniform heat distribution. The temperature of each panel is closely monitored and controlled using small thermal probes integrated into a PID regulatory framework. Additionally, the thermal panels are mounted on adjustable sliders, enabling analysis of how varying distances between the panels and the rotating disk affect thermal image quality.

For real-time monitoring and precise data acquisition, the system employs a 4-channel ADS1115 16-bit analog-to-digital converter module, interfaced with the Arduino microcontroller. The measurement data, including motor speed and thermal panel temperatures, is displayed on a user-friendly 20x4 character LCD, facilitating easy operation and monitoring.

Results obtained at different rotating speed and back panel temperature will be presented and discussed for two thermal time constant uncooled IRFPA microbolometer camera. One available on the market (10 ms) and a prototype one (5 ms) built in the BRIGHTER's framework project.

## Acknowledgments

BRIGHTER project has received funding from the Chips Joint Undertaking (Chips JU) under grant agreement N°101096985. The JU receives support from the European Union's Horizon Europe research and innovation program and France, Belgium, Portugal, Spain, Turkey