Patent ID: 6220513
Filing Date: 2001-04-24
Classification: G06K

Abstract:
A bar code scanner comprising:a laser;an optical assembly having a spinner, the optical assembly being operative to conduct light transmitted by the laser and receive light reflected back from a surface;a motor attached to the spinner, the motor being operative to rotate the optical assembly;a synchronization label attached to the bar code scanner and fixedly positioned to receive and reflect light from the laser when the spinner is at a predetermined angular position; anda position detector for determining the angular position of the motor at the time of a scan, the position detector being operative to receive video data when light from the synchronization label is received and determine the angular position of the motor at the time the light from the synchronization label is received, the position detector being further operative to determine an angular position of the spinner during operation of the bar code scanner by determining the angular position of the motor at the particular time, determining an angular offset of the motor at the particular time from the angular position of the motor at the time the light from the synchronization label is received, and adding the angular offset to the known angular position of the spinner when the light is received from the synchronization label.