Watermarking

The goal of the project was to implement a chosen digital watermark technique in the Stirmark benchmark.
Togheter with Frederic Wegge, I have chosen the DS-CDMA technique. For the presentation we worked togheter with an other group of students, who had chosen the same technique, to make a comparison between the two different solutions.

DS-CDMA is a technique that encrypts the key so it could be spread all over the image. This is done by calcuting a watermark first depending on random values. The explanation of how this is done will be clearer by the figure below. In this figure the b-values are the binary key and the RP values are random generated values..

By adding this watermark to the compliant pixelvalue there will be a small amount of noise and the watermark will be very robust, even after modifications of the image. To detect the watermark in the image you use the calculations below:

The program is written for the .net environment in C++. The implementation can be found in the embeddll.cpp file.

The documents:

• the paper (in dutch)
• the presentation (in dutch)
• the program