Resolving handwriting from background printing using photometric stereo

摘要

We propose a scheme to resolve handwriting from background printing. The scheme detects the indentations made by the pen in the paper. Photometric stereo is used to recover the surface; a matched filter and classifier are used to detect the stroke indentation. We assess the effect of uniform and textured backgrounds on the recovery of the stroke and test the scheme on practical examples. The technique was found to work well with script written with a ballpoint pen and could effectively suppress even dark and strongly textured backgrounds. We conclude that this is a useful complement to existing techniques for background removal and is especially useful when there is no template available.