DIGITAL WATERMARKING

A watermarking method and device to embed a digitized watermark into a digital image file in the transformation domain is disclosed. In the watermarking technology of this invention, the digitized watermark is first error corrected to enhance its robustness. The digital image file to be embedded with the digitized watermark is first processed such that capacity of each element of the digital image file is calculated. The capacity of an element of the digital image file represents the highest value of tolerance for an element of the watermark to be added to the said element of the digital image file. Elements of the digital image file to which watermark elements may be added are selected and their addresses are recorded. The selected elements are then modulated so that they are suited to be embedded with elements of the digital watermark. After modulation the digitized watermark is embedded into the digital file by distributing the modulated elements of the watermark into the selected addresses. A 3*3 mask is used to calculate the capacity of each element of the digital image file.