DMT-based reversible watermarking for CT images

In this paper, a double modification testing (DMT)-based reversible watermarking scheme for use in increasing the capacity of CT images is presented. The scheme works by dividing the image into two parts (region of Dot and region of Cross). All pixels in the two regions are checked according to the definition of DMT i.e., expandable pixel, shiftable pixd, non-expandable pixel and non-shiftable pixel. However, DMT should be modified for use with CT DICOM (16 bits) images. An issue of DMT that is confusing has been solved. A new formula is used for embedding. Moreover, the two-bit embedding strategy is applied for this work. The experimental results demonstrate that the proposed scheme is able to achieve high embedding capacity with low distortion.