K. Korner et R. Windecker, Absolute macroscopic 3-D measurements with the innovative depth-scanning fringe projection technique (DSFP), OPTIK, 112(9), 2001, pp. 433-441
We are presenting a new depth-scanning fringe projection technique (DSFP) o
n the basis of triangulation for the absolute 3-D measurement of a macrosco
pic; scene. The absolute phase can be determined for any desired depth rang
e of the measurement volume. Furthermore, the known limitations of the dept
h of focus occurring by light projection techniques. will be overcome. Duri
ng the measurement procedure, an illuminated Ronchi grating in front of a p
rojection lens is moved both in z- and x-directions by two perpendicularly
arranged linear translation stages. This results in an oblique shift of the
projected grating, resulting in a oblique scan of the projected fringe pat
tern in the measurement volume i.e. the object space. For a well-focussed i
mage acquisition, a CCD-camera placed oil the same z-stage in front of an o
bservation lens takes a series of images of the scene in different z-positi
ons. This focusing allows the use of large apertures and therefore a better
exploitation of light. In our assembled sensor, the triangulation basis of
75 mm approximately corresponds to the distance of a person's pupils.