Patent ID: 8472726

Claim:
A computerized method comprising: a. obtaining a first digital image of a first document page; b. obtaining a second digital image of a second document page; c. performing global geometrical transformation on at least one of said first and second digital images to obtain first and second aligned digital images; d. selecting a window of said first aligned digital image; e. selecting a window of said second aligned digital image; f. estimating residual local geometrical shifts, radiometric differences and blurring differences between said selected windows to obtain a second transformation; g. applying said second transformation to at least one of said windows; h. repeating steps (d) through (g) for consecutive windows of said first and second aligned images to obtain first and second similar images; i. comparing said first and second similar images to obtain a difference image; j. analyzing said difference image to determine whether at least one of the group consisting of: characters, images and components thereof have been added, deleted, changed or shifted; and k. displaying said differences.