
298 ◾ Erwin Hack
e nal step in the measurement process—the transformation of the
phase value into a value of the physical quantity of interest—introduces an
additional uncertainty: the calibration uncertainty. is uncertainty can
either be determined directly using a physical reference material [10, 11]
or be estimated from an analysis, for example, of the sensitivity vector in
digital speckle pattern interferometry (DSPI). In other words, the uncer-
tainty of the phase value must be propagated to the nal result of interest,
such as deformation, shape, or index of refraction. Because this book is
focused on phase measurement, we do not ...