Our approach for solving this problem is to use a line of cameras as a scanner. The system will continuously take images as the vehicle drives over, then mosaic all of those images into a single image used for inspection. The dense coverage of the vehicle bottom by camera images as the vehicle drives over allows for relatively easy mosaicing of the vehicle underside image. As a result of camera view overlap, we can also create multiple mosaics with pseudo-parallel projection representations that preserve the occlusion information from different viewing angles in favor of vehicle inspection.
The algorithm design effort will focus on adapting the geo-registered mosaic methodology
developed
for the UMass
environmental
monitoring program to the problem of generating mosaics from a
"virtual"
bed of 2D camera array for under vehicle inspection. Challenging
technical
issues include (1) calibration of the 1D camera array; (2) estimation
of
the motion of the vehicle while creating the mosaics and (3) seamless
mosaicing
with 2D "array of cameras" with different viewpoints. .
To study some of these issues we captured several single-camera sequences of digital images using the UVIS (Under Vehicle Inspection System) laboratory test facility. The results were very encouraging. Although some minor geometric distortion was observed, we clearly demonstrated the ability of the UMass mosaic algorithm to create smooth, topologically correct mosaics under each of the test conditions. Figure 1 shows a test mosaic made from 4 cameras spaced 4 inches apart with a 45 degree field-of-view.
Figure 1. A test mosaic made from 4 cameras spaced 4 inches apart
with
a 45 degree field-of-view (click picture for the high-resolution
version)
Figure 2. Stereo mosaics for 3D recovery or direct 3D viewing ( click picture to download a Powerpoint slide showing multiple stereo mosaics from 5 different viewing directions)
Howard Schultz, Senior Research Scientist
Gary Whitten, Research Faculty
Allen R. Hanson, Professor
Edward M. Riseman, ProfessorPaul Dickson, graduate student
James Li, undergraduate student
Atlantic Coast Technologies, Inc. (industrial subcontract), Under-Vehicle Inspection System (UVIS), 01/01/01-12/31/01