We developed a method to obtain 3D shape
of object surface from the polarization state of
reflected light on transparent objects observed from two
views.
We set the object into the middle of plastic
white sphere, and illuminate the sphere from three
direction with incandescent lamps. There is a hole on top
of the sphere, and we observed the object from the hole
by polarizer-mounted gray CCD camera. We calculate the
polarization data from 3 or more images taken by rotating
the polarizer each for different angles. Then, we rotate
the object in a small angle with the rotation axis who is
vertical to the viewing direction. We also obtain the
polarization data of the rotated object. We applied a
region segmentation method to both two DOP(degree of
polarization) data. Region segmentation is done so that
the boundary of the region are consisted of locally
maximum DOP. In each region, we detect a point which DOP
is minimum and surface normal is parallel to rotation
direction. We compare two DOPs taken before/after
rotation at such minimum DOP points, and determine the
surface normal. We obtain the surface shape of
transparent objects from calculated surface normal. |
