Laser scanning system mounted over a conveyor belt along which packages bearing bar code symbols are transported and scanned

Abstract

An over-the-conveyor bar code symbol reading system for scanning bar coded packages transported through a 3-D scanning volume having a plurality of focal planes. The system comprises a conveyor belt, first and second laser scanning subsystems mounted thereabove, and a scan data processor. The first laser scanning subsystem generates a first laser scanning pattern above the conveyor belt for scanning each bar coded package transported therealong, and produces bar code position data indicative of the position of the bar code symbol on each scanned package. The second laser scanning subsystem generates and scans a second laser beam to produce a second laser scanning pattern within a 3-D scanning volume above the conveyor belt and having a plurality of focal planes. In response to scanning the transported package, the second laser scanning subsystem produces scan data indicative of the scanned bar code symbol thereon. This scan data is processed to detect each scanned bar code symbol and determine within which one of the plurality of focal planes the detected bar code symbol resides on the transported package. During operation of the system, produced bar code position data is used to automatically set the focal length of the first laser beam to spatially coincide with the focal plane within which the detected bar code symbol resides on the transported package. By virtue of the present invention, bar coded packages of varying height can now be read using a system having reduced complexity and greater compactness for mounting above space-restricted conveyor belts.

Dependencies are inferred from the claim text.