发明名称 |
Background compensating bar code readers |
摘要 |
Methods and apparatus for reading a luminescent and substantially transparent bar code 1 on a background surface 2 whose reflectance may vary over the coded area. Light 7 scans (70), and excites luminescence 8 in, the bar code 1. The light 7 also reflects (9) without luminescence from the background surface 2 of the bar code 1. A first electrical or optical signal 11 is provided (4) responsive to the reflected nonluminescent light 9, and a second electrical or optical signal 10 is provided (4) responsive to the luminescent 8. Typically the first signal 11 is processed (5) to provide a third signal 31 that varies with background reflectance substantially as does the second signal 10; and the second and third signals 10, 31 are combined (5) to provide a fourth signal 12 that is substantially independent of background reflectance in the coded area, and which is decoded (6) to provide the desired reading.
|
申请公布号 |
US4983817(A) |
申请公布日期 |
1991.01.08 |
申请号 |
US19890392171 |
申请日期 |
1989.08.10 |
申请人 |
BATTELLE MEMORIAL INSTITUTE |
发明人 |
DOLASH, THOMAS M.;ANDUS, PAUL G.;O'LOUGHLIN, MARK E. |
分类号 |
B07C3/14;G06K7/10;G06K7/12 |
主分类号 |
B07C3/14 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|