Patent ID: 6415054
Filing Date: 2002-07-02
Classification: B41J,G06K,H04N

Abstract:
A method of decoding, in real time, data stored at a high pitch rate on a print media not withstanding rotations of said print media of up to substantially one degree, said print media comprising data printed in a data area, as a pattern of dots, said data area being at least preceded by a first predetermined number of targets each target printed as a pattern of dots having a plurality of rows and columns with each target offset a predetermined distance from the start of said data area and rotationally invariant under rotations of said print media, said method comprising the steps of:sensing dots on said print media at a high pitch rate; detecting an initial position of said data area by detecting the location of said targets, estimating a line substantially through at least a second predetermined number of said targets from positions located thereon and determining from said line and said location of targets said start of said data area; sensing dots from said data area to form sensed data; decoding the sensed data so as to determine a corresponding bit pattern of said data; wherein said step of decoding commences prior to completion of said step of detecting.