# Imperceptible-Visible Watermarking to Information Security Tasks in Color Imaging
## 6 Discussion and Analysis  
To improve the previously reported algorithm [23], the proposed algorithm takes advantage of the histogram distortion induced by the embedding strategy. The obtained results show that the proposed algorithm has better performance than the most sophisticated and recent algorithm [24]. These results are obtained considering that the embedding region is selected as the largest homogeneous region satisfying the minimum variance; however, in a real-world scenario, the captured scenes can integrate many homogeneous regions that make it possible to embed multiple watermarks. Figure 12a shows an image that  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Algorithm** & **Image Quality** & \multicolumn{2}{c}{**Image Imperceptibility**} \\ \hline  & **PSNR** & **SSIM** & **NCD** \\
[23] & 50.4186 & 0.9978 & 0.0040 \\
[24] & 48.5215 & 0.9951 & 0.0074 \\ Proposed & 51.2145 & 0.9963 & 0.0060 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Image quality and watermark imperceptibility comparison.  
Figure 11: Performance comparison in terms of compression. (**a**) BER vs. JPEG, (**b**) BER vs. JPEG2000.  
once analyzed chooses three non-overlapping regions to embed the proposed watermarks; Figure 12b-d show the corresponding exhibited watermarks.  
The relation between the embedding and the exhibition strategy of [23; 24], and the proposed algorithm is analyzed by the histogram distortion of the embedding region; this relation makes it possible to share the exhibition strategies among them, mainly the histogram modulation-based strategy. Figure 13a is the same multi-watermarked image of Figure 12a, and Figure 13b-d show the results to share among them regarding histogram modulation as the exhibition strategy. These results are possible due to all the algorithms inducing the same histogram distortion in the appropriate embedding region; however, this strategy is not feasible to exhibit QR codes.  
Figure 12: Multi-Watermarked image, (**a**) Watermarked image PSNR = 48.63 dB, SSIM = 0.9964, NDC = 0.0055, (**b**) Exhibited FI watermark, (**c**) Exhibited QR watermark, (**d**) Exhibited UNAM watermark.  
Figure 13: Histogram modulation-based exhibition strategy applied to the proposed algorithm, (**a**) Multi-Watermarked image, (**b**) Exhibited FI watermark, (**c**) Exhibited QR watermark, (**d**) Exhibited UNAM watermark.  
In [24], the reported algorithm is applied on streaming video and images services, where end-users can exhibit the watermark through clicking a media-player button, which executes the corresponding exhibition strategy. To exhibit the watermark, the exhibition strategy shares a crucial parameters set that was embedded previously by the invisible watermarking algorithm QIM-DM [28], the incorporation of this algorithm increasing the computational cost and decreasing the image quality. In this context and taking into account that the most popular on-demand and streaming services, such as Netflix [44], DisneyPlus [45], and PrimeVideo [46], require a dedicated platform to play their audiovisual content, the crucial parameters to exhibit the watermark can be transmitted by the platform and stored into the memory of the electronic display device. When the end-users want to exhibit the watermark, the proposed algorithm takes advantage of robust image processing capabilities; with this strategy, an additional complex computational algorithm is not required to exhibit the watermark. If the proposed algorithm considers the same crucial parameters to exhibit every watermark, the required memory and the computational cost are low.