Normalization techniques for handprinted numerals

A family of pattern standardization techniques based on geometrical projection is applied to a file of digitized handprinted numerals obtained from sales clerks. The principle involves transforming a quadrilateral specified in terms of the convex hull of each pattern into a square. The amount of overlap within each class of characters versus the amount between classes is used to evaluate the degree of normalization achieved with respect to other published methods including size and shear normalization through moments. © 1970, ACM. All rights reserved.