# SIPNet & SAHI: Multiscale Sunspot Extraction for High-Resolution Full Solar Images
## 4 Results and Discussion  
### Instances  
Figure 5a shows a full-disk solar image observed by SDO/HMI on 8 November 2013 at 12:00 UT. It can be seen that there are many multiscale sunspots. We have labeled them from R1 to R11, and they are magnified four times in Figure 5c,d. Figure 5b shows the detection and segmentation result by SIPNet & SAHI. Figure 5c,d show enlarged views of the original sunspot regions and the segmentation results, respectively. For example, the sunspot in the red box of region R9 represents a large sunspot occupying about 600 msh; the sunspot in R11 represents a medium sunspot occupying about 120 msh; the sunspot in R10 represents a small sunspot occupying about 10 msh; and both sunspots in R6 and R8 are ultra-small sunspots occupying about 4 and 3 msh, respectively. Table 1 lists the number of manually counted and detected sunspots with different scales in each region of Figure 5. According to the results proposed by [PERSON] [1,7], we divided the sunspots into six groups according to their sizes: (0, 4] msh, (4, 10] msh, (10, 20] msh, (20, 100] msh, (100, 200] msh, and (200, +\(\infty\)] msh. The large sunspots are in the minority, while the ultra-small sunspots form the majority. There are four missed identifications and four false detections. All of them are ultra-sunspots smaller than 4 msh. For example, the sunspots pointed by red arrows in R1 and R3 are missed, and the sunspots pointed by blue arrows in R2 and R9 are false detected. The comparison results show that the multiscale sunspots in high-resolution solar full-disk images can be effectively detected by this proposed method, especially the ultra-small sunspots. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline
\begin{tabular}{c} **Region/** \\ **msh** \\ \end{tabular} & \multicolumn{2}{c}{**(0, 4]**} & \multicolumn{2}{c}{**(4, 10]**} & \multicolumn{2}{c}{**(10, 20]**} & \multicolumn{2}{c}{**(20, 100]**} & \multicolumn{2}{c}{**(100, 200]**} & \multicolumn{2}{c}{**(200, +\(\infty\)]**} & \multicolumn{2}{c}{**Total**} \\ \hline  & **Manual** & **Detected** & **Manual** & **Detected** & **Manual** & **Detected** & **Manual** & **Detected** & **Manual** & **Detected** & **Manual** & **Detected** \\ \hline R1 & 9 & 7 & 9 & 9 & 0 & 0 & 1 & 1 & 0 & 0 & 0 & 19 & 17 \\ \hline R2 & 2 & 3 & 2 & 2 & 1 & 1 & 0 & 0 & 0 & 0 & 0 & 5 & 6 \\ \hline R3 & 3 & 2 & 4 & 4 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 7 & 6 \\ \hline R4 & 8 & 7 & 1 & 1 & 1 & 1 & 3 & 3 & 1 & 1 & 0 & 0 & 14 & 13 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The number of manual counting and detected sunspots in different scales for each region in Figure 5.  
Figure 5: **(a)** A 4096 \(\times\) 4096 pixel\({}^{2}\) full-disk solar image observed by SDO/HMI on 8 November 2013 at 12:00 UT. The multiscale sunspots are labeled from R1 to R11, which are magnified four times in (**c,d**), respectively. **(b)** The detection and segmentation result of SIPNet & SAHI. **(c,d**)** Enlarged views of the origin sunspot regions and segmentation results, respectively, where the red arrows in R1 and R3 refer to missed sunspots and the blue arrows in R2 and R9 represent misdetected sunspots. Figure 6a shows a relatively quiet solar image observed on 12 September 2013 at 8:00 UT. There are a few small sunspots on the sun, which we have labeled R1 to R4 and are magnified four times in Figure 6c,d. Figure 6b shows the results of the detection and segmentation. Figure 6c,d show enlarged views of the original sunspot regions and the segmentation results, respectively. The sunspot in the red box in R4 is a small sunspot, occupying about 50 msh. The sunspot in R3 is also a small sunspot, occupying about 8 msh. The sunspot in the red box in R2 is an ultra-small sunspot, occupying about 2 msh. Table 2 lists the number of manually counted and detected sunspots with different scales in each region of Figure 6. There are no missed identifications, and only one false