Integration of Thermal and RGB Data Obtained by Means of a Drone for Interdisciplinary Inventory

Abstract

Thermal infrared imagery is very much gaining in importance in the diagnosis of energy losses in cultural heritage through non-destructive measurement methods. Hence, owing to the fact that it is a very innovative and, above all, safe solution, it is possible to determine the condition of the building, locate places exposed to thermal escape, and plan actions to improve the condition of the facility. The presented work is devoted to the technology of creating a dense point cloud and a 3D model, based on data obtained from UAV. It has been shown that it is possible to build a 3D point model based on thermograms with the specified accuracy by using thermal measurement marks and the dense matching method. The results achieved in this way were compared and, as the result of this work, the model obtained from color photos was integrated with the point cloud created on the basis of the thermal images. The discussed approach exploits measurement data obtained with three independent devices (tools/appliances): a Matrice 300 RTK drone (courtesy of NaviGate); a Phantom 4 PRO drone; and a KT-165 thermal imaging camera. A stone church located in the southern part of Poland was chosen as the measuring object.

Condition Assessment of Heritage Buildings via Photogrammetry: A Scoping Review from the Perspective of Decision Makers

“…In particular, this topic aims at relating the visual condition of building surfaces and components with their surveyed physical, mechanical, constructional and performance characteristics. In the case of multispectral imaging, as presented in Section 3.3.1, a direct comparison is enabled between CRP surface colorimetric/metric data and TIR, NIR and/or UV surface data, which might be useful to assess the position and quantitative extent of non-visible anomalies, such as material inhomogeneity [129,130,134], energy losses [131], cracks and mechanical damage [132,136], moist areas [133,135] and weathering patterns [53,60]. Differently, in the case of multisensory data collection, as reported in Section 3.3.2, an indirect comparison is enabled between CRP surface colorimetric/metric data and measurements of constructional discontinuities and pathologies across the components; this comparison is detected as variations in radar reflection from underground structures [143][144][145]147,148]; moist areas [142,146]; or variations in ultrasonic velocities in walls [148,150,151], columns [92,152,153] and pillars [154].…”

“…Differently, in the work by Paziewska and Rzonca [131], the detection of areas showing energy losses on a stone church located in the southern part of Poland was pursued by building a 3D point model based on thermograms by using thermal measurement marks and the dense matching method. Thus, the model obtained from colour photos was integrated with the point cloud created on the basis of the thermal images by migrating the thermal point attributes from the cloud to the vertices of the RGB model.…”

InfraRed Thermography and 3D-Data Fusion for Architectural Heritage: A Scoping Review

“…In comparison to a standard SfM pipeline using TIR images (Workflow 1), fusion methods exploiting RGB and TIR imagery (Workflow 2) demonstrated greater confidence levels, especially for structurally variable buildings. Advances in photogrammetric software are increasing the automation of IRT-3DDF for architectural heritage projects, and whilst software such as Agisoft Metashape is highlighting the capability for thermal models to be generated solely from TIR images [72,73], fusion with RGB-or TLS is fundamental to providing the necessary geometric accuracy for products and insights to be extracted.…”

“…Interestingly, conscious selections of building scale that have been made with the ambition of applying IRT-3DDF to showcase a methodology or application are apparent within the scoping literature. Paziewska and Rzonca [73] employed an unmanned aerial vehicle (UAV) to document a church and its stone tower, comparing an external IRT-3DDF model with internal temperature values to assess thermal leakage. The ability to comprehensively map the tall stone tower externally corroborated findings from internal IRT images that insulation was sufficient.…”

Non-Contact Face Temperature Measurement by Thermopile-Based Data Fusion

“…Current systems offer limited capabilities for remote reconfiguration, such as adjusting calibration data or individual measurement logic. Some researchers are combining RGB and thermal imagery for various applications, such as traffic monitoring and interdisciplinary inventory [ 15 , 16 , 17 ].…”