Patent ID: 6938824

Claim:
A method of correcting for convolution distortion in a laser scanner for sweeping a bar code symbol having elements of wide and narrow widths separated by edges and arranged along a scan direction with an oversized laser beam spot having a spot width, as considered along the scan direction, which is at least two times greater than a minimum element width, the method comprising the steps of: a) detecting light reflected by the oversized beam spot off the elements along the scan direction, and generating an analog signal indicative of the symbol being swept; b) convoluting the analog signal with the oversized beam spot to generate a convoluted signal having peaks and valleys, each peak and valley between adjacent elements of different widths being offset by an edge shift from the edge between the adjacent elements of different widths; c) estimating the edge shift to generate an estimated edge shift; and d) correcting each offset peak and valley by the estimated edge shift to align each offset peak and valley with the edge between the adjacent elements of different widths.