Differential radiation detection apparatus

摘要

The indiction of temperature discontinuities in a scene can be used to indicate the boundaries of objects, for example the level of the contents of a storage silo. The thermal radiation from the object scene is imaged upon a pair of adjacent pyroelectric radiation detectors 9, 10. The scene radiation is chopped and the difference in detector outputs displayed to the observer while the field of view of the detectors, aligned with a visual aiming sight, is traversed across the object. The location and sign of a temperature discontinuity in the visual scene enables the observer to measure the silo contents.