  This paper presents a reversible data hiding in encrypted image (RDHEI),
which divides image into non-overlapping blocks. In each block, central pixel
of the block is considered as leader pixel and others as follower ones. The
prediction errors between the intensity of follower pixels and leader ones are
calculated and analyzed to determine a feature for block embedding capacity.
This feature indicates the amount of data that can be embedded in a block.
Using this pre-process for whole blocks, we vacate rooms before the encryption
of the original image to achieve high embedding capacity. Also, using the
features of all blocks, embedded data is extracted and the original image is
perfectly reconstructed at the decoding phase. In effect, comparing to existent
RDHEI algorithms, embedding capacity is significantly increased in the proposed
algorithm. Experimental results confirm that the proposed algorithm outperforms
state of the art ones.
