Biomedical Engineering Reference
In-Depth Information
Fig. 4
Experimental techniques at LOME/INEGI (
left
) reverse engineering with 3D scanning
[
44
]; (
right
) 3D scans
Fig. 5
Objects, models and techniques available at LOME/INEGI
3D scanner methodology is used to create a point cloud of geometric samples
on the object surface, resulting in a very dense and accurate point set [
13
]. These
points will be used in the reconstruction of the object (Fig.
4
), by extrapolating its
shape and the result can be several types of models depending on how reconstruction
occurs and for which application it is. Point cloud files are used in CAD models
(Solidworks
®
,CATIA
®
), polygon mesh models are used for visualization with
reconstruction software (MeshLab
®
, Photomodeler
®
, Rapidform
®
), surface models,
which are editable, have the advantage of being lighter and more adaptable when
exported to CAD (Rapidform
®
,Geomagic
®
, Rhino
®
), solid CAD models, also
editable, are used in industry and engineering applications, with special relevance
on part design, allowing modelers to create not only the CAD model but also shape
and design of the 3D object (Geomagic
®
,Imageware
®
, Rhino
®
).
At Optics and Experimental Mechanics Laboratory (LOME)/Institute of Me-
chanical Engineering and Industrial Management (INEGI) at Porto, 3D scanning
techniques, like photogrammetry and digital videogrammetry, based on different
optical techniques, such as coherent light, Moire pattern, laser stripes, holography
and others, are been used (Fig.
5
). Two of these techniques are illustrated in
Fig.
6
. The first, Coherent Fringe Projector, consists on a camera and a projector
accommodated in a flexible cart-like structure which can move around and enables
3D acquisition of rather large objects based on phase measurement profilometry
