| The light sectioning principle uses a plane projected onto the object
(Fig. 2). This plane marks a profile-line at the object. All the points
of the line are thus marked optically. Looking to the profile-line from
the viewpoint of the camera, the line appears to be curved in the image.
The lateral displacement shows the elevations and indentations of the
object's surface.
If the position of the light source, the orientation of the light
plane, and the position and orientation of the camera are all known,
a vision system can calculate the position of each of the points on
the bright line in three dimensions. For each profile line one picture
must be captured. To obtain a full depth-scaled image, of, say 500
lines, too much time (here 20 s) is needed for many industrial applications
when using conventional video systems operating at the standard 25
full images per second.
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