First experiments for the Diagnosis and Thermophysical Sampling Using Impulse IR thermography from Unmanned Aerial Vehicle (UAV)
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/19th January 2016, L. E. Mavromatidis, J.-L. Dauvergne, R. Saleri, J.-C. Batsale/ Infrared (IR) thermography is a control method widely used for building diagnosis to investigate structural blemishes and thermal heat losses. Usually, collecting the thermal heat flux naturally emitted by a studied surface via an IR camera, we obtain critical information regarding its structure through passive infrared thermography. The thermogram can then reveal an abnormal variation of the heat flux and highlight a defection.
However, on building applications in the case of Non Destructive Testing and Energy Consumption Investigation, spare control often only emits no significant heat due to the high thermal inertia materials that are often used. To overcome such problem, active impulse infrared thermography is an interesting alternative method, since we can access to information not provided spontaneously by analyzing the passive thermal emission of the surface. Hence, in this work, the front face flash method is proposed in order to analyse the subsurface thermal properties. Furthermore, it is proposed to couple impulse IR thermography with a stable Unmanned Aircraft Systems (UAV) to record and analyse the transient temperature response during convenient time duration. Preliminary results and several practical problems for the implementation of such experimental device are given and discussed here.
According to international normative standards the enhanced amount of old civil infrastructure and residential buildings has become an important issue regarding their energy consumption, their ageing process and hence life cycle management. Conventional means for monitoring the condition of those buildings could not provide the information needed to perform detailed simulation in order to obtain accurate results regarding their thermal performance. Classic UAV mainly provide integral information about cracking condition and possibly detachment of the covering layers of concrete or stone based structures, however, impulse IR thermography from unmanned aerial vehicle could provide more precise information regarding structural degradation on exterior layers and thermophysical sampling.
Furthermore, conducting impulse IR investigation we potentially could be able to estimate with accepted accuracy thermophysical properties of building’s constructive material and hence we could be able to estimate the influence of ageing in thermal performance issues. Effort required in providing this information can become laborious when considering structures of a high altitude since significant lifting equipment is required for such inspection. To circumvent this effort the use of UAV and at small scales of micro aerial vehicles (MAV) equipped with high resolution thermal imaging camera to capture the required data is used in the framework of this paper.
The main purpose of this work is to introduce a simple experimental protocol regarding the realization of simple flash methods combined with UAV active IR thermography systems on large surfaces (for instance for buildings’ evaluations). This first approach has as main objective to investigate and evaluate the technical performances of such a system. The main principle and aim of the experiment is on the one hand to employ a UAV equipped with an IR camera; on the other hand to use a flash lamp that could be implemented independently from the UAV on a stable position or on a second UAV. The first experimental approaches and the technical problems to implement such devices are presented here and compared to classic laboratory experiments.
In the framework of this study, a rotary wing octocopter micro air vehicle (MAV) system (Push-Pull Octocopter DS8X-N3) equipped with a high resolution thermal imaging camera (Flir A320), has been used in laboratory conditions to scan surfaces for defection diagnosis and thermophysical sampling purposes. The MAV has been equipped with a microcontroller based flight control system and different sensors for manual navigation and flight stabilization. Thermograms have been taken at a high speed and frequency, following a real time computer stored procedure while the MAV was up in the air. The IR camera was continuously connected to a PC monitor and provided real-time radiometric thermal images that accurately revealed heat patterns and thermal anomalies.
According to the flight protocol the MAV system flight from 2 up to 8 m distance from the samples while keeping the same altitude throughout the entire experimental procedure. Taken IR images have then been analyzed together to obtain a full 2D image having as main aim to observe damages and cracking in the millimeter range. Furthermore, these pictures have been compared to pictures obtained from stable positioning of the active IR camera system for the same samples and under the same conditions. In a follow-on step an image processing software developed on the LabVIEW environment has been employed while software that allows cracking patterns to be specifically filtered out for further pattern stabilization to erase noising due to MAV’s instabilities has been used in a future step.
The full research paper you can download from here: First experiments for the Diagnosis and Thermophysical Sampling Using Impulse IR thermography from Unmanned Aerial Vehicle (UAV)
According to international normative standards the enhanced amount of old civil infrastructure and residential buildings has become an important issue regarding their energy consumption, their ageing process and hence life cycle management. Conventional means for monitoring the condition of those buildings could not provide the information needed to perform detailed simulation in order to obtain accurate results regarding their thermal performance. Classic UAV mainly provide integral information about cracking condition and possibly detachment of the covering layers of concrete or stone based structures, however, impulse IR thermography from unmanned aerial vehicle could provide more precise information regarding structural degradation on exterior layers and thermophysical sampling.
Furthermore, conducting impulse IR investigation we potentially could be able to estimate with accepted accuracy thermophysical properties of building’s constructive material and hence we could be able to estimate the influence of ageing in thermal performance issues. Effort required in providing this information can become laborious when considering structures of a high altitude since significant lifting equipment is required for such inspection. To circumvent this effort the use of UAV and at small scales of micro aerial vehicles (MAV) equipped with high resolution thermal imaging camera to capture the required data is used in the framework of this paper.
The main purpose of this work is to introduce a simple experimental protocol regarding the realization of simple flash methods combined with UAV active IR thermography systems on large surfaces (for instance for buildings’ evaluations). This first approach has as main objective to investigate and evaluate the technical performances of such a system. The main principle and aim of the experiment is on the one hand to employ a UAV equipped with an IR camera; on the other hand to use a flash lamp that could be implemented independently from the UAV on a stable position or on a second UAV. The first experimental approaches and the technical problems to implement such devices are presented here and compared to classic laboratory experiments.
In the framework of this study, a rotary wing octocopter micro air vehicle (MAV) system (Push-Pull Octocopter DS8X-N3) equipped with a high resolution thermal imaging camera (Flir A320), has been used in laboratory conditions to scan surfaces for defection diagnosis and thermophysical sampling purposes. The MAV has been equipped with a microcontroller based flight control system and different sensors for manual navigation and flight stabilization. Thermograms have been taken at a high speed and frequency, following a real time computer stored procedure while the MAV was up in the air. The IR camera was continuously connected to a PC monitor and provided real-time radiometric thermal images that accurately revealed heat patterns and thermal anomalies.
According to the flight protocol the MAV system flight from 2 up to 8 m distance from the samples while keeping the same altitude throughout the entire experimental procedure. Taken IR images have then been analyzed together to obtain a full 2D image having as main aim to observe damages and cracking in the millimeter range. Furthermore, these pictures have been compared to pictures obtained from stable positioning of the active IR camera system for the same samples and under the same conditions. In a follow-on step an image processing software developed on the LabVIEW environment has been employed while software that allows cracking patterns to be specifically filtered out for further pattern stabilization to erase noising due to MAV’s instabilities has been used in a future step.
The full research paper you can download from here: First experiments for the Diagnosis and Thermophysical Sampling Using Impulse IR thermography from Unmanned Aerial Vehicle (UAV)
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