Patent ID: 7965899

Claim:
A method for processing an image of a two-dimensional (2D) matrix code having a plurality of data modules and a discontinuous finder pattern, each distorted by “donut effects” such that a resulting processed image contains an image of the 2D matrix code having a continuous finder pattern suitable for conventional data matrix locating techniques, and having a plurality of data modules, each data module having a center more truly representative of intended data, and suitable for conventional 2D matrix symbol sampling and decoding, the method comprising: removing noise from the distorted image so as to provide a noise-reduced image with improved signal-to-noise-ratio; sharpening the noise-reduced image so as to remove low frequency image features while preserving high frequency image features, thereby providing a high-pass filtered image; amplifying the sharpened image so as to increase contrast in the sharpened image, thereby providing an amplified sharpened image; and smoothing the amplified high-pass filtered image using a moving window over the high-pass filtered image so as to provide a smoothed image, the moving window and a module of the 2D matrix code being of substantially similar size.