DISCO - Acquisition of Translucent Objects

  1. Abstract
  2. Data Acquisition
  3. Pictures
  4. Movies
  5. Literature

Abstract

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.

Data Acquisition

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.


Acquisition setup.

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.



Movie



Literature