# Data Hiding and Authentication Scheme for Medical Images Using Double POB
## 4 Analysis of Simulation Result
### Comparison with the Related Schemes  
The comparison results between the proposed scheme and some related schemes are shown in Table 5.  
The algorithm in [3] is designed to irreversibly embed message bits to resist attacks, but it cannot recover the original medical image after extracting information bits. For authentication and integrity reasons, the algorithms in [2; 15] embed message bits in a vulnerable way, but they still cannot recover the original medical image. Compared with other algorithms, the algorithm in [16] modifies the sensitive pixel values in the ROI to a greater extent, which is not allowed in the use of medical images. Although the algorithm in [17] considers the ROI, the difference between the watermark image and the original image is still large. Although the algorithm in [23] adopts the secret sharing method to detect tampering, it does not have the function of embedding watermark messages, and it does not consider the sensitive pixels in the ROI. Although POB system based on secret sharing was considered in [20], it could not guarantee lossless recovery. In [19], a method based on POB system was used to hide data in the peak point, but it did not have the function of preventing tamper detection. The method in this paper not only carries additional secret data during image transmission but also makes use of secret sharing to increase the embedding capacity of data and protect the content security of medical images. In addition, it also has an authentication function that can recover the original image through lossless recovery, which is very suitable for the needs of medical images, and it has better performance in data hiding and lossless recovery.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Test Images**}} & **Tampered** & **Tampered** & **PSNR** & **SSIM** \\  & **Region** & **Methods** & & \\ \hline \multirow{2}{*}{\(512\times 512\)} & Brain 01 & ShareA” & cropping (200 \(\times\) 200) & \(\infty\) & \(1\) \\  & Brain 02 & ShareB” & exchange (256 \(\times\) 256) & \(\infty\) & \(1\) \\  & Pulmonary 01 & ShareA” & text addition & \(\infty\) & \(1\) \\  & Pulmonary 02 & ShareB” & cropping (50 \(\times\) 50) & \(\infty\) & \(1\) \\ \hline \hline \end{tabular}
\end{table}
Table 4: PSNR and SSIM of the recovered image under different tampering methods.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Scheme**} & **Watermarking** & \multirow{2}{*}{**Reversibility**} & **ROI** & **Share** & **Tampered** \\  & **Consideration** & & **Consideration** & **Consideration** & **Consideration** \\ \hline [PERSON] [1] & Robust & No & Yes & No & No \\ [PERSON] [2] & Fragile & No & Yes & No & No \\ [PERSON] [3] & Robust & No & No & No & No \\ [PERSON] [15] & Fragile & No & No & No & No \\ [PERSON] [16] & Fragile & Yes & No & No & No \\ [PERSON] [17] & Fragile & Yes & Yes & No & No \\ [PERSON] [23] & None & No & No & Yes & Yes \\ [PERSON] [20] & Robust & Yes & / & Yes & No \\ [PERSON] [19] & Robust & Yes & / & No & No \\ [PERSON] & Robust & Yes & Yes & Yes & Yes \\ \hline \hline \end{tabular}
\end{table}
Table 5: The comparison between the proposed scheme and some related schemes.