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Spatial Sampling of Printed Patterns
March 1998 (vol. 20 no. 3)
pp. 344-351

Abstract—The bitmap obtained by scanning a printed pattern depends on the exact location of the scanning grid relative to the pattern. We consider ideal sampling with a regular lattice of delta functions. The displacement of the lattice relative to the pattern is random and obeys a uniform probability density function defined over a unit cell of the lattice. Random-phase sampling affects the edge-pixels of sampled patterns. The resulting number of distinct bitmaps and their relative frequencies can be predicted from a mapping of the original pattern boundary to the unit cell (called a modulo-grid diagram). The theory is supported by both simulated and experimental results. The modulo-grid diagram may be useful in helping to understand the effects of edge-pixel variation on Optical Character Recognition.

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Index Terms:
Spatial sampling, random phase sampling, digitization, optical character recognition, document defect models, scanner models, modulo-grid diagram, locales.
Prateek Sarkar, George Nagy, Jiangying Zhou, Daniel Lopresti, "Spatial Sampling of Printed Patterns," IEEE Transactions on Pattern Analysis and Machine Intelligence, vol. 20, no. 3, pp. 344-351, March 1998, doi:10.1109/34.667892
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