4. A system comprising: a memory configured to store an image file representing an image comprising text, the text comprising a plurality of letters; and a processing device coupled to the memory, the processing device configured to: classify one or more of the plurality of letters into one of a plurality of initial letterform classes; group a first set of the plurality of initial letterform classes into a first initial letterform class group and a second set of the plurality of initial letterform classes into a second initial letterform class group; generate a data structure comprising terminal nodes representing the initial letterform classes and parent nodes representing the initial letterform class groups wherein a first initial letterform class group represented by a first parent node is associated with a plurality of initial letterform classes of different letters having common letter properties; and merge the first parent node with a second parent node of the data structure to determine a set of final letterform classes using the data structure, wherein each final letterform class of the set of final letterform classes represents a different letterform of one or more of the plurality of letters.
11. The system of claim 4 , wherein the data structure comprises a set of nodes, wherein the set of nodes comprises a plurality of parent nodes, each of the parent nodes associated with one or more terminal nodes, wherein each of the terminal nodes represents an initial letterform class and each of the parent nodes represents an initial letterform class group.