- Fringe projection profiometry (FPP) is a kind of non-contact, active and full-frame 3D measurement method.
- Regular fringe patterns are projected onto the object to be measured. By measuring the changes in the phase angles of the fringe patterns (due to height of the object), the 3D profile of the object can be measured.
- Similar to many phase based imaging systems, a phase unwrapping process is needed at the end since all FPP methods can only provide a modulo-2π estimation of the phase.
- It requires the availability of all wrapped phase data, which cannot be achieved if there is any discontinuity in the fringe image, such as the object has a sharp change in height or the object is occluded by another object.
- In this project, a code pattern is embedded into the fringe pattern to provide the period number of the fringes. Phase unwrapping can thus be restarted from the discontinuity point in the fringe image.
- This work is one the first which applies the sparse dictionary learning technique to FPP.