High-Imperceptibility Data Hiding Scheme for JPEG Images Based on Direction Modification.

Data hiding (DH) is an important technology for securely transmitting secret data in networks, and has increasing become a research hotspot throughout the world. However, for Joint photographic experts group (JPEG) images, it is difficult to balance the contradiction among embedded capacity, visual quality and the file size increment in existing data hiding schemes. Thus, to deal with this problem, a high-imperceptibility data hiding for JPEG images is proposed based on direction modification. First, this proposed scheme sorts all of the quantized discrete cosine transform (DCT) block in ascending order according to the number of non-consecutive-zero alternating current (AC) coefficients. Then it selects non-consecutive-zero AC coefficients with absolute values less than or equal to 1 at the same frequency position in two adjacent blocks for pairing. Finally, the 2-bit secret data can be embedded into a coefficient-pair by using the filled reference matrix and the designed direction modification rules. The experiment was conducted on 5 standard test images and 1000 images of BOSSbase dataset, respectively. The experimental results showed that the visual quality of the proposed scheme was improved by 1~4 dB compared with the comparison schemes, and the file size increment was reduced at most to 15% of the comparison schemes.