Digital watermarking of color image
Shi-Cheng Chao, Hau-Ming Huang, Chi-Yao Chen · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2006
An analytic method of embedding color watermarks into the color images is proposed. The original image is color image of size 480X640, and the watermark image is 24-bit-gray scale image of size 120X160. The quality variations of the embedded image and extracted watermark are analyzed. From the experimental results they appear that the quality of embedded image varies with the quantization index (QI). They also show that the quality of extracted watermark is dependent on the gray-level of the original image. The relationship between the gray-level and the noise of embedded image has been quantitatively analyzed. The digital quantization method is also important to decrease the noise of embedding image and the error of extracting watermark.