DISCO - Acquisition of Translucent Objects
- Data Acquisition
Translucent objects are characterized by diffuse light scattering
beneath the object's surface. Light enters and leaves an object at
possibly distinct surface locations. This paper presents the first
method to acquire this transport behavior for arbitrary
inhomogeneous objects. Individual surface points are illuminated in
our DISCO measurement facility and the object's impulse response is
recorded with a high-dynamic range video camera. The acquired data
is resampled into a hierarchical model of the object's light
scattering properties. Missing values are consistently interpolated
resulting in measurement-based, complete and accurate
representations of real translucent objects which can be rendered
with various algorithms.
We acquire the geometry of the object by use of a 3D scanner, e.g. a
structured light or computer tomography scanner, yielding a triangular
mesh. In order to capture the subsurface scattering a laser beam
illuminates each surface point individually, and a HDR video camera is
used to measure the impulse response of all other surface points. In
order to illuminate all points the laser sweeps over the surface and
the object is rotated from time to time. In order to capture all
surface points the camera is placed at different locations. The
overall acquisition process takes 8 to 20 hours.
Here some pictures
Horse Head - back lighting
Left: Photograph of a back lit alabaster horse. Right: Rendered image of the acquired model.
Horse Head - projected shadow edge
Rendered response to local illumination caused by casting a shadow edge. From left to right: incident illumination, response closed to the point of incidence, global part, combined result.
Comparison with two different gamma settings to show both the local and the global light transport. Left: Photograph under projected shadow edge. Right: Renderings.
M. Goesele, H.P.A. Lensch, J. Lang, C. Fuchs, H.-P. Seidel:
DISCO - Acquisition of Translucent Objects.
Proc. of SIGGRAPH '04 (Special issue of ACM Transactions on
Graphics), 2004, 835-844
- H.P.A. Lensch, M. Goesele, P. Bekaert, J. Kautz, M.A. Magnor, J. Lang and H.-P. Seidel:
Interactive Rendering of Translucent
Proc. of Pacific Graphics 2002, Beijing, China, October, 9-11, IEEE Computer Society, Los Alamitos, 2002, 214-224.