http://eia.udg.es/~qsalvi/papers/2010-PR.pdf

A state of the art in structured light patterns for surface profilometry

Phase shifting algorithms for fringe projection profilometry: A review

http://eia.udg.edu/~qsalvi/papers/2010-IVC.pdf

Efficient multiple phase shift patterns for dense 3D acquisition in structured light scanning

3D imaging has been widely used within various fields of dentistry to aid diagnosis, in treatment planning and appliance construction. Whereas traditionally this has involved the use of impression materials together with plaster or stone models, modern techniques are continually evolving which use virtual 3D images. These electronic virtual images are created using either contact or non-contact optical scanning techniques, but there are limitations, the most important of which is that any new virtual surface image is created from a series of discrete data points. It is not created from a continuous stream of data relating to the original object. This means that computer software has to be used to recreate a possible best fit, virtual surface from the data obtained. This paper describes the principles behind 3D scanning technology, the limitations of 3D imaging as well as current and possible uses of such imaging in clinical dentistry.

3D surface imaging in dentistry - what we are looking at.

Surface profile measurement of moving objects by using an improved π phase-shifting Fourier transform profilometry

In Fourier transform profilometry (FTP), the zero frequency of the imaged patterns will influence the measurement range and precision. The π phase shifting technique is usually used to eliminate the zero order component, but this method requires the capture of two fringe patterns with a π phase difference between them, which will impede the real time application of the method. In this paper, a novel method is proposed, in which a composite structured light pattern is projected onto the object. The composite structured light pattern is formed by modulating two separate fringe patterns with a π phase difference along the orthogonal direction of the two distinct carrier frequencies. This method can eliminate the zero frequency by using only one fringe pattern. Experiments show that there is no decrease in the precision of this novel method compared with the traditional π phase shifting technique.

Yong-Zhi Liu

Papers

Fourier transform profilometry based on composite structured light pattern