Fast Watermark Detection Scheme From Camera-Captured Images On Mobile Phones

Digital watermarking technology would be very useful as part of a related service introduction system (RSIS); which links physical objects in the real world, such as printed photographs, to those in the cyber world. In this paper, we focus on a camera-equipped mobile phone as an RSIS terminal, and propose a fast watermark detection scheme for the captured images. The proposed scheme consists of two processes: to correct geometric distortion of the captured image, and to detect watermark information from the corrected image. For our scheme, we also propose a fast quadrangle detection algorithm and a robust watermarking algorithm. Moreover, we introduce a quantitative evaluation method for determining the reliability of watermark detection, which is essential for RSIS services. Finally, we show that the proposed scheme enables users to detect embedded information far less than one second, even when implemented as a Java application on a mobile phone with limited resources, and our experiments confirm the efficiency of our scheme.