The Using Of Lateral Shearing Interferometry In3D Measuring By Lighting Projection

Three-dimensional shape measurement based on structured light method is one of the most important measurement,In this technique,the phase have been limited in (-π,π] range,In order to obtain the correct phase.we must carry on the expansion of the wrapped phase (Also known as phase unwrapping),Therefore the phase unwrapping is a key technique in structured light3D measurement. In the actual situation,Because the fringe breaks, the shadow and noise etc, Especially the under-sampling effect,a lot of residual points will be introduced.Phase unwrapping is difficult, even on failure, thus it affect the3D shape recovery.Aimed at the problem on how to realize the phase unwrapping in the under sampling,many algorithms have been proposed and make some success in different degree.But in more serious under-sampling,many algorithms’s ability of resisting under-sampling is not satisfactory.In this paper,we do the research on how to apply the least squares algorithm based on the principle of transverse shear (LSBLS) to phase’s expansion in grating projection.First the wrapped phase obtained from the grating projection is constructed light field,Finally,do phase unwrapping combining with the least squares.This algorithm is applied to the projected grating phase unwrapping.We found the first shearing also can’t get correct results,when under-sampling is very serious.So we improved this algorithm and do the second shearing on the construction’s light field based on the first shearing to further reduce the spatial frequency phase. Thus proposed the improved phase unwrapping algorithmSimulation and experimental results show that the introduction of the LSBLS algorithm can realize phase expansion in the serious under sampling, this algorithm can get the better result than the traditional least squares algorithms The results also show that the improved LSBLS algorithm can also get the good result in very serious under-sampling.The algorithm can guarantee that the correct result can be obtained when the absolute value of two order discrete derivative is less π...