Compensating aperture for utilizing shearography from a moving platform

摘要

The invention allows a shearography system to successfully sense ground/surface vibrations while moving at aircraft speeds and altitudes. This is done by effectively making stationary the apparent location of a coherent laser beam illuminating an area on the ground/surface, and also effectively making stationary the apparent location of the aperture of an optical receiver which acquires pairs of sequential images captured and used for shearography. A different laser is used for capturing each of the two images, and the distance between the two lasers is adjusted based on a number of operational parameters. The adjustment of the distance causes the apparent locations of the transmitter and a receiver sub-aperture to remain the same and permits the moving shearography to work.