## 3 Proposed Technique
### Watermark Extraction Process
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Image** & **(a)** & **(b)** & **(c)** & **(d)** & **(e)** & **(f)** & **(g)** & **(h)** & **(i)** \\ \hline PSNR & 59.24 & 59.38 & 59.07 & 59.18 & 59.55 & 59.43 & 59.21 & 59.34 & 59.38 \\ \hline Average PSNR & 59.308 & & & & & & & \\ \hline NC & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 & 1.0000 \\ \hline SSIM & 0.9987 & 0.9991 & 0.9983 & 0.9988 & 0.9995 & 0.9992 & 0.9993 & 0.9991 & 0.9991 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: PSNR of different types of colour medical images and SSIM and NC of the extracted watermark without attack. Figure 6: No Attack: Watermarked Image and Extracted Watermark. #### 4.1.1 JPEG Compression

Amidst the COVID-19 pandemic, patients were diagnosed utilising a remote approach. Medical images are frequently transmitted through diverse communication channels. The medical images were either purposefully or accidentally compressed and transformed throughout this procedure. The quality of converted medical images is always lower than the original. Consequently, JPEG compression has rapidly become an established and indispensable tool in the field of image processing. We examined extracted watermark images with various quality parameters scale (from 40 to 90) in Figure 7. The NC and SSIM values that were obtained through the course of our investigation are presented in Table 2. The NC values range from 0.9634 to 1.0 for quality factors 40-90. However, the obtained SSIM values range from 0.8642 to 0.9712 for quality factors 40-90. The obtained results demonstrate that, when exposed to a JPEG compression attack, the proposed approach performed better than expected. Furthermore, upon conducting a comparative analysis of the outcomes with other pre-existing methodologies, namely [28; 30; 31; 32], concerning quality factors 80 and 90 (as presented in Table 3), it was observed that the outcomes of [28; 32] exhibit a resemblance to the proposed scheme at a quality factor of 90. At a quality factor of 80, it can be observed that only the reference [32] is in closer proximity to the subject matter being discussed. Thus, it can be inferred that the proposed methodology exhibited superior performance in comparison to various analogous methodologies. #### 4.1.2 Filtering Attack

The images are distorted by the communication channel signals. The watermark image is also subject to interpolation attacks involving distortion or signal processing. This presents a novel prospect to acquire knowledge on image processing methodologies, \begin{table}
\begin{tabular}{c c c} \hline \hline
**Quality Parameter** & **NC** & **SSIM** \\ \hline
90 & 1 & 0.9712 \\
80 & 0.9985 & 0.9611 \\
70 & 0.9943 & 0.9523 \\
60 & 0.9823 & 0.9383 \\
50 & 0.9774 & 0.8976 \\
40 & 0.9634 & 0.8642 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: JPEG Compression: NC and SSIM of Extracted Watermark. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**QF** & **Proposed Work** & [28] & [31] & [30] & [32] \\ \hline
90 & 1.0000 & 1.0000 & 0.9941 & 0.9901 & 1.0000 \\
80 & 0.9985 & 0.9781 & 0.9897 & 0.9813 & 0.9945 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison of NC Values over JPEG Compression Attack. Figure 7: Extracted watermark after JPEG compression attacks with different quality factors. including the filter attack technique. The performance of the proposed watermarking scheme was effectively evaluated in our experiment, specifically in the context of a filtering attack. The results depicted in Figure 8 indicate that the extraction of the watermark image from the distorted watermarked image remains feasible despite the presence of a filtering attack. The aforementioned outcome exhibits the durability of the watermarking methodology, thus holding potential for further development. The results of our experiment are presented in Table 4, which provides a valuable foundation for subsequent analysis. The findings indicate that the envisaged system exhibited satisfactory performance, even in the presence of a filtering attack.