Copyright Embedding Analysis in Color Image Channel based on Non-Blind DCT Method

Image watermarking is the most popular copyright protection technique. Discrete Cosine Transform (DCT) is a transformation method that is still widely used today in image watermarking research. In the grayscale cover image there is only one channel so that the watermark is directly inserted on the channel, while the color cover image generally uses red, green and blue (RGB) color channels. Some previous research did direct copyright insertion on one color channel based on hypothesis and color theory related to the sensitivity of changes in pixel values to the human visual system. So, this research aims to carry out watermarking technique analysis based on the non-blind DCT method on color cover images. The watermarked image was tested by measuring image quality and watermark resistance to attacks. Based on the results of the tests that have been conducted, it can be concluded that the red channel has the best quality based on the value of MSE and PSNR, while the green channel has the best SSIM value. While for the durability of the blue channel watermark has the best average resistance based on the correlation calculation of the results of watermark image extraction.