A method for aligning a modified document and an original document for emphasizing differences, the method comprising: receiving a first bitmap representative of the modified document, and a second bitmap representative of the original document, the first and second bitmaps each being defined by a plurality of pixels arranged in ordered rows and columns from a left side to a right side, each of the pixels having X-Y pixel coordinates associated therewith; deriving a set of first vertex coordinates for the first bitmap and a set of second vertex coordinates for the second bitmap; aligning the documents by transforming the first bitmap to a common reference based upon the first set of vertex coordinates; and transforming the second bitmap to the common reference based upon the second set of vertex coordinates; wherein transforming the bitmaps includes deriving the sets of vertex coordinates by: storing in a first list for the bitmap the X-pixel coordinates of a leftmost pixel matching a trigger value in every row of the bitmap; storing in a second list for the bitmap the X-pixel coordinates of a rightmost pixel matching the trigger value in every row of the bitmap; storing in sample coordinates lists for the bitmap a subset of the X-pixel coordinates in the first and second list for the bitmap starting with the top as well as the bottom of the lists; evaluating if the respective standard deviation of X-pixel coordinates in the sample coordinates lists is sufficiently small and then if the evaluating step is passed, assigning average pixel coordinates of the respective sample coordinates lists to the set of vertex coordinates for the bitmaps. receiving a first bitmap representative of the modified document, and a second bitmap representative of the original document, the first and second bitmaps each being defined by a plurality of pixels arranged in ordered rows and columns from a left side to a right side, each of the pixels having X-Y pixel coordinates associated therewith; deriving a set of first vertex coordinates for the first bitmap and a set of second vertex coordinates for the second bitmap; aligning the documents by transforming the first bitmap to a common reference based upon the first set of vertex coordinates; and transforming the second bitmap to the common reference based upon the second set of vertex coordinates; wherein transforming the bitmaps includes deriving the sets of vertex coordinates by: storing in a first list for the bitmap the X-pixel coordinates of a leftmost pixel matching a trigger value in every row of the bitmap; storing in a second list for the bitmap the X-pixel coordinates of a rightmost pixel matching the trigger value in every row of the bitmap; storing in sample coordinates lists for the bitmap a subset of the X-pixel coordinates in the first and second list for the bitmap starting with the top as well as the bottom of the lists; evaluating if the respective standard deviation of X-pixel coordinates in the sample coordinates lists is sufficiently small and then if the evaluating step is passed, assigning average pixel coordinates of the respective sample coordinates lists to the set of vertex coordinates for the bitmaps. storing in a first list for the bitmap the X-pixel coordinates of a leftmost pixel matching a trigger value in every row of the bitmap; storing in a second list for the bitmap the X-pixel coordinates of a rightmost pixel matching the trigger value in every row of the bitmap; storing in sample coordinates lists for the bitmap a subset of the X-pixel coordinates in the first and second list for the bitmap starting with the top as well as the bottom of the lists; evaluating if the respective standard deviation of X-pixel coordinates in the sample coordinates lists is sufficiently small and then if the evaluating step is passed, assigning average pixel coordinates of the respective sample coordinates lists to the set of vertex coordinates for the bitmaps.