[OPTICAL REVIEW Vol. 8, No. 4 (2001) 235-240]

Detection of Label Area by Comb-Shaped Illumination

Masataka SHIRATSUCHI* and Yoshinori HONGUH

Corporate R&D Center, Toshiba Corporation, 1 Komukai-Toshiba-cho, Saiwai-ku, Kawasaki, 212-8582 Japan

(Received January 30, 2001; Accepted June 19, 2001)

We have developed a non-contacting technique to detect small steps on a surface such as label edges on a letter by using a spatially modulated illumination. Steps can be detected correctly with this new technique even if there are printed patterns on the same surface. Thus the technique is effective for determining label areas that are often seen on pieces of direct mail.

Key words : step difference, comb-shaped illumination, address label, cellophane window, letter handling machine, optical character recognition