哈尔滨工业大学学报(英文版)
哈爾濱工業大學學報(英文版)
합이빈공업대학학보(영문판)
JOURNAL OF HARBIN INSTITUTE OF TECHNOLOGY
2004年
3期
237-239
,共3页
copyright notification%visible watermark%HVS%quantization index modulation
A multipurpose image watermarking technique based on DCT is proposed to notify and protect the copyright of digital products. In order to achieve this objective, the DCT coefficients of each image block are divided into two parts for embedding the visible and invisible watermarks. The visible watermark is embedded in each DC DCT coefficient and most of the AC DCT coefficients of every block, and the invisible watermark in the rest. Based on the characteristics of Human Visual System (HVS) , the embedding strength of the visible watermark is varied in accordance with the underlying content of the host image. The invisible watermark is embedded in a quaternity of midrange frequencies. Experimental results show that the visible watermark is hard to remove and the invisible watermark is robust to common digital signal processing operations.
