PERFORMANCE EVALUATION OF THERMOGRAPHIC CAMERAS FOR PHOTOGRAMMETRIC DOCUMENTATION OF HISTORICAL BUILDINGS

Abstract

Thermographic cameras record temperatures emitted by objects in the infrared
region. These thermal images can be used for texture analysis and deformation
caused by moisture and isolation problems. For accurate geometric survey of the
deformations, the geometric calibration and performance evaluation of the
thermographic camera should be conducted properly. In this study, an approach is
proposed for the geometric calibration of the thermal cameras for the geometric
survey of deformation caused by moisture. A 3D test object was designed and used
for the geometric calibration and performance evaluation. The geometric calibration
parameters, including focal length, position of principal point, and radial and
tangential distortions, were determined for both the thermographic and the digital
camera. The digital image rectification performance of the thermographic camera
was tested for photogrammetric documentation of deformation caused by moisture.
The obtained results from the thermographic camera were compared with the results
from digital camera based on the experimental investigation performed on a study
area.