A reversible steganographic scheme for VQ indices based on joint neighboring coding

• A novel reversible steganographic scheme for VQ indices based in joint neighboring coding is proposed.
• The proposed scheme can embed n secret bits into one VQ index, where n = 1, 2, 3, or 4.
• The proposed scheme can provide high embedding rates, low bit rates, and high embedding efficiencies.

Obtaining a high embedding rate measured in bit per index (bpi) and a low bit rate measured in bit per pixel (bpp) is the main goal of a reversible data hiding scheme in the vector quantization (VQ) compressed domain. This paper proposes a reversible steganographic scheme for VQ indexes based on the joint neighboring coding technique. The proposed method uses the difference values between the current VQ index and the left, upper, top-left neighboring VQ indices, and their combinations to embed n secret bits into one VQ index. The experimental results show that the proposed scheme achieves the different embedding rates of 0.984, 1.969, 2.953, and 3.938 bpi and average bit rates of 0.426, 0.503, 0.571, and 0.634 bpp for n = 1, 2, 3, and 4, respectively. These results confirm that the proposed scheme surpasses other selected reversible data hiding schemes.