Patent ID: 7583387

Claim:
An instrument for studying an object, comprising: an interferometer having a source of coherent object light and a source producing a reference beam which is coherent with the object beam, and detector, in which: the coherent light source is expanded and arranged to direct a converging object beam towards a point beyond the object and to produce a reflected object beam reflected from the object; the reflected object beam and reference beam combine to produce a speckle pattern of light representing the effects of the reflection from the object; and the speckle pattern is detected by the detector, wherein: the detector comprises a plurality of arrays of detectors; the detector arrays are arranged in a line extending in the direction of movement of the instruments; the instrument further includes means for generating at least one additional converging laser beam; there are at least three detector arrays, each arranged to detect a speckle pattern of light reflected from a respective laser beam; and the three detector arrays are arranged to have three different sensitivity directions.