The detection of bridge deck delaminations using Infrared Thermography is carried out according to ASTM D 4788 –03 using high-resolution, distance-triggered infrared and video cameras operated from an elevated platform attached to a survey vehicle. The infrared camera is capable of capturing a full lane width of data per driving pass, has a frame rate of 60 frames per second, and thermal sensitivity of less than 0.1 degree C. All data collection is carried out at normal driving speeds so that typically no closures are required. In some cases, infrared data can also be collected using fixed-wing aircraft or Unmanned Aerial Vehicles (UAV), such as drones.
Available in “cooled” and “uncooled” models that are optimized for different applications. “Cooled” cameras use cryocoolers integrated into the image sensor in order to reduce thermally-induced noise to levels below those of the recording signal. This technology allows the camera to record extremely narrow temperature differences, target small thermal targets, and record at high frame rates for crisp images during high-speed data collection, perfect for high-speed vehicle-based surveys. The compromise is that these cameras are heavier and more expensive; uncooled cameras use standard microbolometer technology, which allows the camera to be lightweight and more affordable. Microbolometer IR cameras are more appropriate for UAV and slow-speed vehicle mounted surveys.