Abstract: A camera contains a row of diodes sensitive to infrared radiation and mounted on a turntable for rotation about the optical axis of the camera. The signals from the diodes provide a temperature profile of a band across the width of a strip of hot rolled steel moving in a direction orthogonal to the optical axis and to the length of the row of diodes. Since the diodes are low accuracy devices, their measurements are compensated by normalizing co-efficients derived by comparison with the signal provided by an optical pyrometer viewing the central part of the steel strip in the region of the optical axis. To enable all diodes to be calibrated, calibration is effected with the turntable rotated 90.degree. to align all the diodes with the central part of the strip as viewed by the pyrometer. The camera may be mounted on one arm of a C-frame having X-ray tubes in an arm and X-ray detectors in the other arm for the purpose of measuring the thickness profile of the strip in known way.

Abstract: A thermal reference source which includes a blackbody element and which is capable of being either heated or cooled based on a measured temperature of a scene of interest of an infrared system.

Abstract: Apparatus for calibrating and testing infrared detection devices is provided. The apparatus comprises a substrate which supports a target pattern of dielectric material which is at least partially absorbing to infrared radiation. A heater is used to supply heat to the substrate. Since the substrate and dielectric material have different emissivities, an apparent temperature difference is perceived by an IR detection device. As a consequence, temperature differences as low as about 0.02.degree. C. and below can be generated for calibrating and testing IR imaging devices.