A research project evaluated the application of infrared thermography for the detection of asphalt cracking. Such detection has generally relied on image processing of pictures and videos of asphalt produced by analog and digital cameras that operate in the visual range of light The presence of shadows, poor light conditions, white cracks, and a variety of other problems have presented serious challenges to automated crack identification and detection in this frequency region. The research reported here is primarily aimed at testing the hypothesis that asphalt cracks cause changes to surface conditions and emissivity, leading to perceived temperature differentials that can be exploited by infrared detectors in cameras. The research involved the production of tens of images from both conventional and infrared cameras. Several parameters were evaluated for both flexible and rigid pavements, including choice of infrared detection range, various lenses, and exposure during day and night hours. Under the right conditions, infrared thermography can yield superior results and allow the identification of tiny cracks about 1 mm in width, which are virtually impossible to detect with conventional cameras.
