Conference,
A New Robust Watermarking Scheme for Document Images by Randomized Distribution of Watermark Segments
(2014)
Abstract
A new robust watermarking scheme for protection of document image contents
using redundant watermark segments is proposed in this work. A wavelet-based
watermarking scheme for embedding a logo has been developed for robust watermarking.
At the sender side, a level-2 wavelet transformation is applied on the source document
image. LL-sub-band of level-2 of the transformed image is subdivided into blocks of
uniform size. A logo watermark of size same as the transformed image block is considered.
The watermark is divided into a number of segments. A number of sets of transformed
image blocks are formed pseudo-randomly and the total size of all the blocks in a set is
equal to the size of the watermark. The watermark segments are embedded into blocks of
each set using quantization technique. The amount of quantization is controlled based on its
strength. Thus, multiple copies of watermark are available and each input image block
need not include the entire watermark. At the receiver side, the extracted segments from
each set of blocks are merged to obtain a single extracted watermark. Based on the
quantization step-size, size of the logo and the level of wavelet transform, the watermark is
extracted without accessing the original image. The experimental results show that the
proposed technique is highly robust. The performance evaluation results show that the
proposed approach is better t
han the existing method 1.
