# A Comparative Analysis of Feature Detectors and Descriptors for Image Stitching
## Appendix A  
We also considered six publicly available datasets: (1) apartment dataset [77], (2) MATLAB dataset (MATLAB vision toolbox dataset), (3) synthetic dataset [78], (4) river dataset (VLFeat dataset), (5) garden dataset [77] and (6) UAV dataset [79]. Input images used from these datasets are shown in Figure 11. The stitched images obtained using different combinations of feature detectors and descriptors from these datasets are shown in Figures 12-17.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Dataset 1** & \multicolumn{3}{c}{**Dataset 2**} & \multicolumn{3}{c}{**Dataset 3**} \\ \hline
**Method** & **Rank** & **Method** & **Rank** & **Method** & **Rank** \\ \hline AKAZE + AKAZE & 1 & AKAZE + AKAZE & 1 & AKAZE + AKAZE & 1 \\ BRISK + FREAK & 2 & SIFT + FREAK & 2 & AGAST + BRIEF & 2 \\ AKAZE + ORB & 2 & Star + BRIEF & 2 & SIFT + BRIEF & 3 \\ AGAST + BRISK & 3 & KAZE + ORB & 3 & AKAZE + FREAK & 4 \\ BRISK + BRIEF & 3 & MSER + DAISY & 3 & AGAST + ORB & 5 \\ SURF + ORB & 3 & AKAZE + FREAK & 4 & AGAST + DAISY & 5 \\ GFT + BRISK & 4 & BRISK + ORB & 4 & SIFT + SIFT & 5 \\ AKAZE + BRISK & 4 & MSER + SURF & 5 & GFTT + SIFT & 6 \\ GFTT + DAISY & 5 & KAZE + FREAK & 5 & GFTT + BRIEF & 6 \\ FAST + BRISK & 5 & KAZE + SURF & 6 & MSD + FREAK & 7 \\ \hline \hline \end{tabular}
\end{table}
Table 20: Top ten detector–descriptor combinations for each dataset.  
Figure 10 shows a subset of output stitched images obtained using various detector-descriptor combinations for the apartment dataset. The first and second rows show a subset of stitched images obtained using different detector-descriptor combinations, which produces a good quality of stitched image in comparison to all other combinations. The third row shows a subset of stitched outputs using different detector-descriptor combinations, which produces poor quality of stitched images. It was observed that AKAZE + AKAZE produced a better quality of stitched image in comparison to all other combinations.  
In Figure 11, a collection of stitched images generated from a range of detector-descriptor combinations on the MATLAB dataset is displayed. The first and second rows exhibit examples of high-quality stitched images, while the third row showcases a sample of poorly stitched outputs resulting from different detector-descriptor combinations. It was noted that the AKAZE + AKAZE combination produced the highest quality stitched image compared to all other combinations.  
Figure 14 displays a variety of stitched images created from a selection of detector-descriptor combinations on the synthetic dataset. The first and second rows illustrate instances of well-stitched images, while the third row features a subset of poorly stitched outputs that resulted from various detector-descriptor combinations. The AKAZE + AKAZE and AGAST + BRIEF combinations were observed to produce the highest quality stitched images compared to all other combinations.  
In Figure 14, a variety of stitched output images obtained from different detector-descriptor combinations on the garden dataset are showcased. The first and second rows exhibit a subset of well-stitched outputs that displayed superior quality compared to all other combinations. Conversely, the third row features a subset of poorly stitched outputs resulting from various detector-descriptor combinations. It was observed that the AKAZE + AKAZE combination produced the highest quality stitched image among all the combinations tested.  
Figure 14 displays a selection of stitched output images that were produced using different detector-descriptor combinations on the UAV dataset. The first and second rows exhibit a subset of well-stitched outputs that demonstrated superior quality compared to all other combinations. However, the third row features a subset of poorly stitched outputs resulting from various detector-descriptor combinations, as evidenced by the outputs in the last row. Among all the combinations tested, it was observed that the AKAZE + AKAZE produced the highest quality stitched image.