Improved Ultimate Link without Markers for Projective Transformation

In our previous work, we have proposed a method that links character string having a certain semantic meaning on papers in real world to the digital content in cyberspace, and call it "Ultimate Link." Ultimate Link adds additional information to characters by drawing colored circles on top of the characters without changing the shape of the characters. A URL can be generated by connecting additional information of semantically organized character strings from an image taken with a digital device. The conventional Ultimate Link drew markers to normalize the drawn circles (markers for projective transformation), similar to the finder pattern in a QR code. In order to achieve a more realistic application, it is desirable it. We report on an improved Ultimate Link that can handle complex multiple character strings. Specifically, improvements were made to enable extraction of information by identifying character strings with embedded additional information from sheets of paper printed with multiple character strings. As a result of experiments, we confirmed that information could be successfully embedded and extracted for both character strings in the target image.