Modified Multiway Pixel-Value Differencing Methods Based on General Quantization Ranges for Image Steganography

Abstract

A new modified multiway pixel-value differencing steganographic methods using general quantization ranges of pixel pairs' difference values is proposed (where the quantization range is not limited to the power of two), which can be employed to embed secret messages into cover images with a higher embedding rate. The cover images are partitioned into non-overlapping complete or incomplete blocks by using 1×3, 2×2, 2×3, or 3×3 block templates. All the resulting blocks can be embedded with a bitstream of messages whose bit positions are randomized by a random numbering mechanism. Firstly, one pixel in each block is set as a shared pixel; the least significant bits substitution method with the optimal pixel adjustment process is used to embed message bits into the shared pixel. Then, the shared pixel forms multiple pixel pairs with the remaining pixels in the block. Each pixel pair is used to embed message bits by the pixel-value differencing method. A multiple-based number conversion mechanism is employed to implement the use of non-power-of-two range widths, with each shared pixel and each pixel pair being used to embed a digit in the multiple-based number. Accordingly, all the message bits are transformed into a big multiple-based number whose digits are then embedded into the shared pixels and the pixel pairs with a higher embedding rate. Pixel pairs are checked for falling-off-boundary before embedding messages, and the pairs that are likely to be out of bounds are not embedded. The experimental results show that the embedding rates of the proposed data hiding method are higher than that of the existing multiway pixel-value differencing method. The stegoimages after embedding secret messages retain good image quality, and the RS steganalysis cannot detect the presence of the secret messages.INDEX TERMS general quantization ranges, multiway pixel-value differencing, steganography, data hiding, multiple-based number conversion.

Enhancing Steganography through Optimized Quantization Tables

“…Additionally, despite its improved capacity, the technique could remain vulnerable to sophisticated steganalysis methods if not executed with precision, particularly as detection technologies for steganography continue to advance. In [22], a changed multiway pixel-value differencing method using universal quantization ranges to make image steganography better was explained. This approach boosts embedding rates while maintaining high image quality.…”