Automated Glass Fragmentation Analysis
Abstract
This paper describes a novel automated inspection
process for tempered safety glass. The system is geared toward the
European Community (EC) import regulations which are based on fragment
count and dimensions in a fractured glass sample. The automation of
this test presents two key challenges: image acquisition, and robust
particle segmentation. The image acquisition must perform well both
for clear and opaque glass. Opaque regions of glass are common in the
American auto industry due to painted styling or adhesives (e.g.
defroster cables). The system presented uses a multiple light source,
reflected light imaging technique, rather than transmitted light
imaging which is often used in manual versions of this inspection
test. Segmentation of the glass fragments in the resulting images
must produce clean and completely connected crack lines in order to
compute the correct particle count. Processing must be therefore be
robust with respect to noise in the imaging process such as dust and
glint on the glass. The system presented takes advantage of
mathematical morphology algorithms, in particular the watershed
algorithm, to perform robust preprocessing and segmentation. Example
images and image segmentation results are shown for tempered safety
glass which has been painted on the outside edges for styling
purposes.
Keywords: segmentation, morphology, inspection, fracture analysis
G. G. Gordon, "Automated Glass Fragmentation Analysis",
Proc. of the
SPIE, Machine Vision Applications in Industrial Inspection IV,
Vol. 2665, San Jose, CA Feb 1996.