9. A method comprising: identifying a plurality of document features in a document image; correlating each of the plurality of document features with one or more of different document classes; selecting a first group of document features and a second group of document features from the plurality of document features based on document feature types of the plurality of document features; for the first group of document features, generating a first decision tree that includes one or more nodes corresponding to document features of a document feature type corresponding to the first group; for the second group of document features, generating a second decision tree that includes one or more nodes corresponding to document features of a document feature type corresponding to the second group; and associating the document image with one of the different document classes based at least in part on the first decision tree and the second decision tree.
9. A method comprising: identifying a plurality of document features in a document image; correlating each of the plurality of document features with one or more of different document classes; selecting a first group of document features and a second group of document features from the plurality of document features based on document feature types of the plurality of document features; for the first group of document features, generating a first decision tree that includes one or more nodes corresponding to document features of a document feature type corresponding to the first group; for the second group of document features, generating a second decision tree that includes one or more nodes corresponding to document features of a document feature type corresponding to the second group; and associating the document image with one of the different document classes based at least in part on the first decision tree and the second decision tree. 10. The method of claim 9 , wherein: the feature is a feature that was previously determined to be a feature capable of distinguishing the document image or a document that comprises the document image, and the feature was previously identified by analysis of a plurality of training documents each having at least one unique feature different from at least one of the other training documents.