Digital holographic interferometry and speckle interferometry applied on objects with heterogeneous reflecting...

In digital holographic and speckle interferometry devoted to solid object displacement measurement, the reflecting properties of the object under study are of importance in designing the observation and laser illumination systems. In practical cases, the objects can show separate zones in which the surface property can simultaneously cause either scattering or specular reflectivity. We present strategies for dealing with both reflectivity types at a time in digital holographic and speckle interferometers. The scattered surface is illuminated with a point source whereas the specular one is illuminated by a diffuser. Both types of surfaces visible across the field-of-view give rise to a specific interferogram with gaps in between, which in turn are interpreted separately related to the sensitivity vector, the latter being defined differently for scattering and specular areas.