A method for aligning a modified document and an original document is provided according to an aspect of the present invention. The method includes a step of receiving a first bitmap representative of the modified document, including a first anchor. Additionally, a second bitmap representative of the original document including a second anchor is received. The method also includes the step of deriving a set of first vertex coordinates of the first anchor, and a set of second vertex coordinates of the second anchor. The method further includes the step of transforming the first bitmap to a common reference based upon the first set of vertex coordinates, and the step of transforming the second bitmap to the common reference based upon the second set of vertex coordinates.