Use Of Close Range Objective Speckles For Displacement Measurement

Abstract

In the past two decades, speckle photography and its electronic counterpart have been extensively used for displacement measurement purposes, the applications ranging from civil engineering over biomechanical field to astronomy. In most applications, a more or less sophisticated imaging process is involved. The simplest way of normal photographing, however, is placing the emulsion in contact with the object; this concept can also be used for speckle correlation purposes. If coherent illumination is used, one can speak about objective speckles; it will be shown that incoherent illumination can also be used, during both recording and data interpretation stages.