Digital watermarking in digital images

The paper presents some properties of digital image watermarking based on discrete orthogonal transforms (DCT-discrete cosine transform and KLT-Karhunen Loeve Transform). This contribution is focused on the logical describing of watermarking method. In this paper basic analysis for the process of watermark implementation is presented. Comparing of two digital watermarking methods, both based on discrete orthogonal transforms, is described. In generally, discrete orthogonal transforms (mainly DCT) is a base for loss image compression. All information, which may be lost during lossy compression, is possible to leave in the image and these information may be modified during watermark embedding. Thus, a question is satisfying of remaining watermark requirements.