Apparatus and method for reading a luminescent bar code on a background surface whose reflectance may vary over the coded area, including a light source for providing light to scan, and to excite luminescence in the bar code or to reflect from the background surface of the coded area; a first detector...http://www.google.ca/patents/US6119071?utm_source=gb-gplus-sharePatent US6119071 - Edge effect compensating bar code reader
