Achieving Stronger Compaction for DCT-Based Steganography: A Region-Growing Approach

Abstract

The strong energy compaction property of the Discrete Cosine Transform (DCT) has inspired researchers to utilize the DCT transform technique in steganography. The DCT transform can effectively represent a signal within a few significant coefficients leaving a large area with insignificant coefficients that can be safely replaced by a substantial amount of secret data. It has been proven that this strong energy compaction property has a relation with the correlation of the signal. The higher the correlation, the stronger the compaction, and thus more data can be hidden. Therefore, several state-of-the-art image steganography techniques tend to segment the cover image into homogeneous segments to exploit the strong compaction property of the DCT. In this paper, a precise segmentation process using the region-growing segmentation method is applied to maximize the homogeneity level between pixels in a segment, and thus, maximizing the hiding capacity while achieving improved stego quality.