Seamless stitching with shape deformation for historical document images

In historical document images stitching, the arbitrary placement and the low quality of the historical paper always bring in uneven surface of the document, which might introduce local distortion to the image content. In these situations, some traditional methods may fail to find an optimal seam as they just use the content similarity. Some other methods tried to find two corresponding seams in both images, and the contents of the two images at the opposite sides of seams are transformed and stitched together. Although the image contents are correctly aligned with these methods, the transform may lead to huge content deformation and geometric inconsistency. To solve this problem, we proposed a seamless stitching method with shape deformation. In this method, one of the images is first deformed to approximate the other image, then single or dual optimal seams are estimated using an optimization method to minimize the deformation and to maximize the deformation consistency. With this method, the deformation of image content along the seam is consistent, and geometrically consistent elements such as straight lines can be well preserved. Experimental results show the effectiveness and efficiency of the proposed method.