(ii) Digital camera. A Color Digital Camera (CDC), model
Power Shot A70 (Canon, USA), was located vertically
over the sample at a distance of 22 cm. A black cover
was used over the sample illuminators and the CDC to
avoid the external light and reflections. Images of the
originally adjoining faces of the chips were taken on a
matte black background using a resolution of
1024768 pixels and stored in jpg format. The CDC
was connected to the USB port of a personal computer
Pentium III to acquire and store the images.