## 4 Experimental Results and Discussion
### Stereoscopic Image SR Results
#### 4.3.2 Contrast with Depth-Based Methods  
To show the advantages of the proposed method, which fully leverages the correspondence between views without estimating the depth map, comparative experiments were carried out between the depth-based method presented by [PERSON] and the proposed method. As mentioned in [PERSON]'s work [22], for fully considering the high-frequency information of original images, the test sequences, including Dog, Pantomime, Pozan Street, Ballet, and Breakdancers, were resized to \(640\times 480\)  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Images** & **Resolution** & **Scale** & **SC [13]** & **SRCNN [15]** & **Proposed** \\ \hline Sword2 & 2856 \(\times\) 2000 & 2 & 46.76/0.9857 & 51.07/0.9951 & 51.35/0.9951 \\ Umbrella & 2960 \(\times\) 2016 & 2 & 48.11/0.9897 & 51.08/0.9954 & 51.93/0.9955 \\ Vintage & 2912 \(\times\) 1924 & 2 & 40.84/0.9855 & 42.11/0.9903 & 42.23/0.9894 \\ Champagne\_tower & 1280 \(\times\) 960 & 2 & 43.76/0.9856 & 44.83/0.9917 & 46.42/0.9921 \\ Dog & 1280 \(\times\) 960 & 2 & 43.88/0.9799 & 46.20/0.9901 & 46.66/0.9903 \\ Pantomime & 1280 \(\times\) 960 & 2 & 45.71/0.9906 & 46.41/0.9942 & 47.91/0.9948 \\ Newspaper & 1024 \(\times\) 768 & 2 & 41.21/0.9720 & 42.60/0.9834 & 42.54/0.9832 \\ Pozan Street & 1920 \(\times\) 1088 & 2 & 40.77/0.9600 & 42.49/0.9787 & 42.69/0.9788 \\ Ballet & 1024 \(\times\) 768 & 2 & 41.01/0.9590 & 42.40/0.9699 & 42.82/0.9714 \\ Breakdancers & 1024 \(\times\) 768 & 2 & 41.08/0.9402 & 42.44/0.9573 & 42.42/0.9573 \\ Average & - & 2 & 43.31/0.9748 & 45.16/0.9846 & 45.70/0.9848 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Comparison with SC [13] and SRCNN [15] for PSNR (dB)/ structural similarity index (SSIM).  
Figure 10: SR results and PSNR values in the Y channel for the first frame of the Pantomime sequence. (**a**) Ground truth; (**b**) local amplification region of the ground truth; (**c**) local amplification region of SC [13]; (**d**) local amplification region of SRCNN [15]; and (**e**) local amplification region of the proposed method.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Images** & **Resolution** & **Scale** & **SC [13]** & **SRCNN [15]** & **Proposed** \\ \hline Sword2 & 2856 \(\times\) 2000 & 2 & 67.94 & 48.05 & 46.34 \\ Umbrella & 2960 \(\times\) 2016 & 2 & 77.60 & 41.75 & 40.20 \\ Vintage & 2912 \(\times\) 1924 & 2 & 62.65 & 42.70 & 37.65 \\ Champagne\_tower & 1280 \(\times\) 960 & 2 & 62.23 & 39.89 & 36.81 \\ Dog & 1280 \(\times\) 960 & 2 & 42.29 & 40.31 & 38.39 \\ Pantomime & 1280 \(\times\) 960 & 2 & 79.83 & 40.77 & 40.39 \\ Newspaper & 1024 \(\times\) 768 & 2 & 46.70 & 36.86 & 34.21 \\ Pozan Street & 1920 \(\times\) 1088 & 2 & 47.65 & 41.25 & 38.79 \\ Ballet & 1024 \(\times\) 768 & 2 & 63.22 & 41.77 & 39.26 \\ Breakdancers & 1024 \(\times\) 768 & 2 & 52.09 & 32.56 & 30.53 \\ Average & - & 2 & 60.22 & 40.59 & 38.56 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparison with SC [13] and SRCNN [15] for blind/referenceless image spatial quality evaluator (BRISQUE).  
640 \(\times\) 480, 960 \(\times\) 544, 512 \(\times\) 384, and 256 \(\times\) 192, respectively, by using a six-tap Lanczos interpolation filter. To ensure consistency, we employed these downsampled images for testing the original images under the same conditions.  
As depicted in Table 3, the average PSNR value of the proposed method increased by 1.14 dB compared with [PERSON]'s method [22]. Two significant characteristics of the proposed method contributed to the improvement; (1) the estimation of the high-precision view difference image between views owing to modified CNN in the first stage and (2) the gradual improvement of the reconstructed right view by enforcing the global reconstruction constraint to incorporate the right view.