## 6 Quality Analysis of the Reconstructed Image
### Review and Analysis of Subjective Measurement Results  
In this article, the subjective assessment of image quality is performed using the double stimulus continuous quality scale. The image evaluation was performed by 40 observers, 8 of whom were female and 32 of whom were male. The observers first saw the original image, then the same image or the decoded image was shown. The subjective evaluation was performed using Table 22. After grading, the cumulative MOS was calculated for each tested image. The analysis for the image _horse_ is shown in Table 23.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Rating** & **Quantity** \\ \hline
1 & Unwatchable \\
2 & Barely watchable \\
3 & Watchable \\
4 & Good \\
5 & Excellent \\ \hline \hline \end{tabular}
\end{table}
Table 22: Image quality ratings.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Rating** & **Distortion** \\ \hline
1 & Particularly irritating \\
2 & Irritating \\
3 & Slightly irritating \\
4 & Noticeably \\
5 & Not noticeably \\ \hline \hline \end{tabular}
\end{table}
Table 21: Image distortion ratings.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**bpp** & **JPEG** & **JPEG 2000** & **EDDC BSSP** \\ \hline
0.8 & 4.53 & 4.52 & 4.13 \\
0.4 & 3.41 & 3.80 & 4.24 \\
0.2 & 2.06 & 2.81 & 2.65 \\
0.1 & 1.23 & 1.61 & 1.96 \\
0.05 & / & 1.13 & 1.57 \\ \hline \hline \end{tabular}
\end{table}
Table 23: MOS values for image _horse_ at various compression ratios.  
The values provided and the corresponding graph show that, for image _beauty_, JPEG 2000 performs best at all compression ratios except 0.05 bpp, and JPEG performs by far the worst at all compression ratios.  
The calculated values of MOS for the test image _mask_ are listed in Table 25. The graph of agreement is shown in Figure 20.  
For the image _mask_, JPEG was rated the worst for all compression ratios, but still JPEG 2000 and EEDC-BSSP are very close according to the results. It is really hard to distinguish these two algorithms for this image. The results for these two algorithms are similar except that, at 0.2 bpp, JPEG 2000 was rated as better than EEDC-BSSP, but, at 0.4 bpp, the roles reversed, i.e., EEDC-BSSP was better than JPEG 2000.  
The numerical values of the MOS rating for the _pills_ image are provided in Table 26 and the graph for this image is shown in Figure 21.  
For the image _pills_, JPEG 2000 was generally rated as the best compression method, but had a lower value than EEDC-BSSP at 0.2 bpp (seen as a \"drop\" at 0.2 bpp in Figure 21). Interestingly, JPEG was ranked better than EEDC-BSSP at 0.8 bpp, but all other values followed the same regularity as the previous images.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**bpp** & **JPEG** & **JPEG 2000** & **EEDC BSSP** \\ \hline
0.8 & 4.73 & 4.84 & 4.00 \\
0.4 & 3.16 & 3.92 & 3.62 \\
0.2 & 2.40 & 2.34 & 2.73 \\
0.1 & 1.22 & 1.91 & 1.76 \\
0.05 & / & 1.00 & 1.14 \\ \hline \hline \end{tabular}
\end{table}
Table 26: MOS values for image _pills_ at various compression ratios.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**bpp** & **JPEG** & **JPEG 2000** & **EEDC BSSP** \\ \hline
0.8 & 4.91 & 4.95 & 4.92 \\
0.4 & 3.50 & 4.04 & 4.46 \\
0.2 & 2.91 & 3.36 & 3.16 \\
0.1 & 2.05 & 2.16 & 2.17 \\
0.05 & / & 1.16 & 1.11 \\ \hline \hline \end{tabular}
\end{table}
Table 25: MOS values for image _mask_ at various compression ratios.  
Figure 20: MOS values comparison for EEDC-BSSP with JPEG and JPEG 2000 for image _mask_.