Data-Hiding Scheme Using Multidirectional Pixel-Value Differencing on Colour Images
Algorithm 4
The proposed extraction algorithm.
In the extraction process, we split the two stego colour images into nonoverlapping blocks and decompose each colour image into R, G, and B. Then, the PVD extraction algorithm is applied to R, G, and B to extract secret data. The extraction algorithm is as follows.
Step 1: Divide the two stego colour images and into 2 2 size blocks. If the -th block is , then the pixels in are defined as .
Step 2: Decompose two stego colour images and into R, G, and B. is decomposed into ,, and
Step 3: Extract the secret data by using the following equation. means extraction algorithm of PVD scheme. .
