Four test images were used, namely (a) Barbara, (b) Boat, (c) Lena, and (d) Peppers. All of them are 512×512 pixels gray-scale images, which are shown in Fig. 9. The experiment uses the MATLAB random function generator to generate a sequence of bit streams as the secret data. The peak signal-to-noise ratio (PSNR), defined as
Figure 9. Ten test images with the size of 512×512 pixels and 256 levels (8 bits) per pixel: (a) Barbara, (b) Boat, (c) Lena, (d) Peppers, (e) Airplane, (f) Couple, (g) Elaine, (h) House, (i) Lake, and (j) Tiffany.
where MSE is the mean square error between the cover image and stego-image, (1) can be used to evaluate the distortion of the stego-image after the secret data have been embedded. MSE is defended as
where pi, j and qi, j represent the pixel values of the cover image I and the stego-image SI, respectively. The embedding capacity (EC) is defined as the maximal number of bits that can be embedded for each pixel (bpp).
If the PSNR value gets larger, then the quality of the image is closer to its original image. In general, a PSNR value greater than 30 dB indicates the closeness of the stego-image and the cover image. Thus, the quality of the stego-image with the PSNR value greater than 30 dB is taken as perceptually acceptable.
Table 1 shows the comparison of the proposed scheme with the other three related schemes proposed by Chang et al., Chang et al., and Lee et al., respectively, in terms of the embedding capacity and image quality. From Table 1, the proposed scheme has 2 bpp of embedded capacity which is the same with the Pencil-shape scheme and higher than those of the schemes proposed by Chang et al. and Chang et al..
Name Sudoku scheme Turtle-shape scheme Pencil-shape scheme Proposed scheme PSNR (dB) EC (bpp) PSNR (dB) EC (bpp) PSNR (dB) EC (bpp) PSNR (dB) EC (bpp) Lena 44.97 1.5 49.42 1.5 42.87 2.0 44.14 2.0 Baboon 44.68 1.5 49.39 1.5 42.88 2.0 44.14 2.0 Peppers 44.67 1.5 49.40 1.5 42.88 2.0 44.14 2.0 Airplane 45.02 1.5 49.39 1.5 42.84 2.0 44.17 2.0 Boat 44.94 1.5 49.40 1.5 42.88 2.0 44.02 2.0 Average 44.85 1.5 49.40 1.5 42.87 2.0 44.12 2.0
Table 1. PSNR and embedding capacity (EC)
Experimental results show that the proposed scheme, in comparison with Sudoku and Turtle-shaped schemes, outperforms in terms of embedding capacity and security. However, compared with Sudoku and Turtle-shaped schemes, it outperforms in terms of embedding capacity and security, but needs to pay the cost of image distortion. Compared with the pencil-shaped pattern embedding scheme, the proposed scheme has an equal amount of embedding capacity, but our scheme improves the image visual quality. The average PSNR values reach 44.12 dB higher than that with 42.87 dB of the pencil-shape scheme. Table 1 shows lower PSNR values compared with those of schemes proposed by Chang et al. and Chang et al.. However, when weighing up the relative advantages of embedding capacity and image quality in PSNR values, we are more concerned about whether our method has a higher payload. High embedding capacity indicates the better ability of information embedding and transmission. That means, under the same level of imperceptivity, that a cover image can carry more secret messages at once, which will earn in the data transfer rate, thus further reducing transmission complexity.
In Table 2, we use test images such as Lena, Baboon, Peppers, Airplane, and Boat to observe the change of image quality under different payloads in the proposed method. This experimental result shows the payloads at each stage are 1×105 bits, 2×105 bits, 3×105 bits, 4×105 bits, and 5×105 bits, respectively, and the corresponding image quality by PSNR will change with the payload. For example, when the payload is 1×105 bits, PSNR of Lena, Baboon, Peppers, Airplane, and Boat reaches 53.9 dB on average. Next, when the payload is 2×105 bits, PSNR reaches 50.9 dB on average. Even if the payload is up to 5×105 bits, PSNR still preserves in 46.9 dB on average. PSNR of each image is very close at each stage of payload; thus, our proposed method has good stability.
Name PSNR under various payloads Payloads (bits) 1×105 2×105 3×105 4×105 5×105 Lena 53.9464 50.9252 49.1569 47.9134 46.9423 Baboon 53.9069 50.9398 49.1622 47.9175 46.9447 Peppers 53.9426 50.9436 49.1790 47.9174 46.9472 Airplane 53.9471 50.9410 49.1633 47.9195 46.9551 Boat 53.9520 50.9373 49.1814 47.9382 46.9444
Table 2. Proposed method results of PSNR under various payloads
Secure Image Hiding Scheme Based on Magic Signet
- Received Date: 2018-02-06
- Rev Recd Date: 2018-05-07
- Available Online: 2020-05-06
- Publish Date: 2020-03-01
Abstract: Image data hiding technology is secret communications that carry hidden data in such a way that no one except the sender and intended recipients can even realize there is a hidden message. High embedding capacity, good images quality, and security are three important essentials. In this paper, each confidential hexadecimal will be carried by two cover pixels based on a magic matrix generated from a square template to reach the goal of higher embedding capacity while keeping good image visualization. Experimental results reveal that the proposed scheme guarantees higher embedding capacity of 2 bits per pixel and has the peak signal-to-noise ratio (PSNR) of 44.7 dB on average. Moreover, secret keys are used to ensure security consideration.
|Citation:||Chin-Feng Lee, Ying-Xiang Wang. Secure Image Hiding Scheme Based on Magic Signet[J]. Journal of Electronic Science and Technology, 2020, 18(1): 93-101. doi: 10.11989/JEST.1674-862X.80206200|