Look-Up Table 기법을 이용한 하프톤 영상의 워터마킹 알고리즘 = Watermarking Algorithm for Halftone Image Using Look-Up Table Method

다국어 초록 (Multilingual Abstract)

In this paper, we propose a new watermark algorithm for halftone images using LUT(Look-Up Table) method. In the proposed method, watermark bits are hidden at pseudo-random locations within a halftone image. To remove the distortions due to the inserted watermark bits and increase the invisibility of watermark, the best halftone pixel are chosen from LUT considering both of the contone value of the current pixel and its neighborhood pixels. The LUT
halftoning will require no arithmetic operations other than memory access. The LUT is built from a sample set of images and halftones of these images. In order to be robust to geometrical modification like cropping or rotation, we insert the same watermark periodically into halftone images. Experiments using printed and scanned images show that the proposed method is a robust method to the geometrical modification and to hide the large amount of data within a halftone image without noticeable distortion.