Statistical features of speckle-patterns for stereophotogrammetric 3D-reconstruction

In an active stereophotogrammetric setup sinusoidal, bandlimited or speckle-patterns are projected sequentially onto an object to find a time based correlation. Out of these three only the speckle-patterns have a high depth of field and allow at the same time a high speed pattern generation. However their statistics limit their application compared to, for example, band limited patterns. The histogram of a speckle-distribution shows a clear concentration of intensities around an average value. In this work, we present a technique for speckle-based setups to decrease this disadvantageous effect by frequency filtering of the pattern and adapting the reconstruction algorithm to the statistical features of speckle-patterns. Possible advantages and disadvantages for the performance are investigated.