...other
We shall defer a detailed discussion of the nature of the transformation until Section  5 .
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...lengths
Since the images were acquired using a camera mounted a fixed distance above the tabletop, matching words should have approximately the same length in the two images. For more general viewing conditions, matching could be attempted using the relative lengths of adjacent words.
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A.H. Gee
Wed Jun 25 11:02:12 BST 1997