BTFDBB: BTF Database Bonn and Measurement Lab

Dome setup from outside.
One side of the camera-hemisphere with sample holder (bottom).
Camera-hemisphere as seen through the empty sample holder.
Close up of the cameras installed on the gantry.

The camera DOME

The camera Dome is a prototypical setup for the rapid synchronous acquisition of BTF materials. The hardware consists of 151 digital consumer cameras mounted on a rack and is completely computer-controlled.

The functionality of this setup is demonstrated in the following video, showing the example acquisition of a 3D object with BTF:

undefinedMultiview Dome 3D Object Acquisition.mpg

Originally, the Dome was equipped with 151 Canon PowerShot A75 cameras, evenly distributed over the hemisphere with an angular spacing of 15 degrees. As of mid 2009 these have been completely replaced by the better Canon PowerShot G9 model, exhibiting a spatial resolution of 12 Megapixels.

The cameras are remotely controlled via USB2.0 and are connected to a total of 8 control-computers, facilitating the direct transfer of the cameras' data to the computer's hardrives in a matter of seconds.

The main reasoning behind this setup is the simultaneous acquisition of 151 different view directions, improving capture times considerably with respect to the old measurement device. The cameras are also used as light sources, illuminating the material-sample with their internal flashes. Thus, a bidirectional angular sampling of 151 x 151 is achieved.

From August 2011 on, the dome is also equipped with 9 additional LG HS200G projectors, allowing for the automated acquisition of whole 3D objects.