Method of aligning page images

A method of aligning a first page image and a second page image is disclosed. The first page image and the second page image are deskewed. Then, the first page image and the second page image are vertically aligned. In particular, a first vertical data set comprising a plurality of first values each first value based on a horizontal scanline of the first page image is generated. Moreover, a second vertical data set comprising a plurality of second values each second value based on a horizontal scanline of the second page image is generated. One of the first and second vertical data sets is dilated. Then, the first and second vertical data sets are cross-correlated to generate cross-correlation data. A maximum value of the cross-correlation data is determined, whereas the maximum value indicates vertical alignment between the first and second page images. Finally, the first and second page images are horizontally aligned.