Position Detection For a Camera Pen Using LLAH and Dot Patterns

In this report, we present a method of position detection for a low-cost camera-pen. Our method allows reconstruction of handwriting, as well as retrieval of the particular document that is being written onto. For this matter, we use a point pattern printed onto the document’s background, which is indexed using Locally Likely Arrangement Hashing. For position detection, the dot pattern is extracted from the camera image and then matched to the hash table. Experimental results show high retrieval accuracy (80.4%∼100.0%) when the pattern is disturbed by the document’s foreground only to a certain extent.