1. A method for identifying a particular template paper form of which a selected paper form is an instance based on digital images of the particular template paper form and the selected paper form, the method comprising: generating a template form library by: for each template form of a plurality of template forms: extracting, by a processor implementing a first visual feature extractor, a first plurality of visual features for said each template form based on an image of said each template form; extracting, by the processor implementing a second visual feature extractor, a second plurality of visual features for said each template form based on the image of said each template form; determining, by the processor implementing a clustering algorithm, a plurality of clusters of visual features based on any of the first plurality or the second plurality of visual features; determining, by the processor implementing a bag of visual words vector algorithm, a bag of visual words vector for said each template form based on the plurality of clusters of visual features; and storing, by the processor, the first plurality of visual features, the second plurality of visual features, and the bag of visual words vector; preparing to identify a template form of the plurality of template forms of which a selected form is an instance by: extracting, by the processor implementing the first visual feature extractor, a first plurality of visual features of the selected form based on an image of the selected form, the selected form being an instance of a particular template form of the plurality of template forms; extracting, by the processor implementing the second visual feature extractor, a second plurality of visual features of the selected form based on the image of the selected form; determining, by the processor implementing the clustering algorithm, a first plurality of clusters of visual features of the selected form based on any of the first plurality or the second plurality of visual features of the selected form; and determining, by the processor implementing the bag of visual words vector algorithm, a first bag of visual words vector for the selected form based on the first plurality of clusters of visual features; identifying a first set of candidate template forms of which the selected form may be an instance by: identifying, by the processor implementing a first classifier, a first set of potentially matching template forms of the plurality of template forms based on a correlation between the first plurality of visual features of the selected form and visual features of a first subset of the plurality of template forms extracted by the first visual feature extractor; identifying, by the processor implementing a second classifier, a second set of potentially matching template forms of the plurality of template forms based on a correlation between the second plurality of visual features of the selected form and visual features of a second subset of the plurality of template forms extracted by the second visual feature extractor; and identifying, by the processor implementing a third classifier, a third set of potentially matching template forms of the plurality of template forms based on a correlation between the first bag of visual words vector for the selected template form and a subset of bag of visual words vectors of the plurality of template forms; and identifying the particular template form of which the selected form is an instance by: when the first set, the second set, and the third set of potentially matching template forms are all a same template form: identifying, by the processor, the same template form as being the particular template form of which the selected form is an instance; and when the first set, the second set, and the third set of potentially matching template forms are not all the same template form: comparing, by the processor implementing a matching algorithm, the image of the selected form to images of the first set, the second set, and the third set of potentially matching template forms, and based on results of said comparing, identifying, by the processor, the particular template form of which the selected form is an instance.