Fringe Projection Profilometry measures 3D shape by projecting striped light patterns onto an object and reading how the stripes bend. When you shrink the projector down to a tiny diffractive optical element, though, the patterns come out distorted in nonlinear ways, and the depth reconstruction picks up bad phase errors.

The authors correct this by modeling the errors along the rays leaving the projector's pinhole, using the projector's geometry rather than smoothing things in the image itself. They add a way to estimate that pinhole from a single hyperbolic fringe pattern, so no stereo calibration is needed, and they build the correction from just one calibration pose to keep it data-light. Experiments on miniaturized DOE systems show clearer improvements in accuracy under these distorted conditions.

This is a plain read of a fairly technical abstract, so see the paper for the geometry and validation details.