A method for data embedding to printed images based on use of original images

A data embedding to printed images has become an important issue for several applications. In this paper, we assume an original image to be known and the server based data retrieval model, and a new method for the data embedding to the printed images is proposed. For data embedding to printed image, a method using spread spectrum technique has already been proposed. However, there are two problems in this method. One is the small number of data bits and another is misdetection due to the distortion and noise by printing and image capturing. In this paper, we proposed the use of ldquoWalsh coderdquo for diffusion code to increase the number of data bits. This can be also applied to the improvement of the detection process. This technique gives the tolerance to some distortions and noises. In the detection processing, a captured image is forwarded to the server which holds the original image and the embedded data is detected in it. Therefore, the improvement of the detection process by using original image is proposed. As a result, more data embedding and more accurate detection becomes possible than the conventional method.