Matching of Double-Sided Document Images to Remove Interference

The National Archives of Singapore keeps a large volume of historical handwritten documents. One common problem with the archives is that over the years, ink sipped through the pages of these documents such that characters on the reverse side become visible and interfere with the characters on the front side. This paper addresses this problem and develops a novel algorithm to extract clear textual images from the interference. We achieve this by mapping images from both sides of a page such that interfering strokes seen on the front side are matched with the strokes originating from the reverse side so as to achieve a cancellation effect. The resultant image is further subjected to an improved Canny edge detection to eliminate remaining background interference. Experimental results have confirmed the validity of our proposed method.