# Weak-Edge Extraction of Nuclear Plate Fuel Neutron Images at Low Lining Degree
## 5 Conclusions  
Our study aimed at meeting various challenges facing plate fuel neutron imaging at low lining degrees. This paper provides a PC-based approach to edge extraction. The proposed method has the following features:  
1. The use of the classical perceptual field mode enhances the details of neutron images, thereby improving the clarity of weak edges;
2. The introduction of the PC model utilizes its contrast-invariant property rather than relying on image gradient changes and can detect weak edges with slow grayscale changes. In addition, calculating the amplitude and phase in six directions improves the accuracy of the edge localization;
3. The non-maximum suppression further ensures precise localization and avoids edge breaks;
4. The area-opening mathematical morphology operation eliminates noise, such as pseudo-edges, resulting in clean binary edge results.  
This method effectively solves the problem of cladding edge breakage and missing in fuel neutron images and obtains a complete and accurate boundary of the fuel pellet and its cladding, with an improved edge integrity of 64.1% and edge positioning accuracy reaching 94.3% compared with conventional gradient methods. This new approach to edge extraction for fuel element neutron images will be of great practical value in our follow-up, improving the enrichment analysis of fuel elements. In addition, it has a certain level of robustness and generality to be applied in other neutron image processing scenarios.  
Conceptualization, Q.W. and B.T.; data curation, Y.S. and Y.W.; methodology, Q.W. and Y.L.; writing--original draft preparation, Q.W. and Y.L.; writing--review and editing, Y.S. and S.P.; project administration, S.P. and X.T.; funding acquisition, S.P. and X.T.; All authors contributed to discussing and analyzing the results. All authors have read and agreed to the published version of the manuscript.  
This work was funded in part by the National Natural Science Foundation of China, (Grant No. 42004151), the Sichuan Postdoctoral Research Program (Grant No. TB2022035), the Nuclear Energy Development Research Program (Research on High Energy X-ray Imaging of Nuclear Fuel).  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**Image and Method** & **A** & **B** & **C** & **C/A** & **C/B** \\ \hline \multirow{2}{*}{zirconium alloy} & Canny & 28.587 & 3743 & 423 & 0.0148 & 0.0920 \\  & Sobel & 18.396 & 6713 & 1324 & 0.0720 & 0.1972 \\  & Ours & 17.278 & 5205 & 240 & 0.0138 & 0.0813 \\ \hline \multirow{2}{*}{red nuclear fuel} & Canny & 16,125 & 1845 & 356 & 0.0221 & 0.1930 \\  & Sobel & 12,042 & 2724 & 351 & 0.0291 & 0.1289 \\ \cline{1-1}  & Ours & 34,258 & 2877 & 207 & 0.0060 & 0.0719 \\ \hline \multirow{2}{*}{mechanical structural component neutron image} & Canny & 49.863 & 7912 & 1401 & 0.0281 & 0.1771 \\  & Sobel & 28.961 & 10,441 & 2829 & 0.0977 & 0.2710 \\ \cline{1-1}  & Ours & 26,658 & 6131 & 376 & 0.0141 & 0.0613 \\ \hline \end{tabular}
\end{table}
Table 4: Result of edge evaluation method based on connection component for three different materials neutron images.  
Data Availability Statement: All the data generated and analyzed during this study are included in this paper or are available from the corresponding authors on reasonable request.  
The authors declare no conflict of interest.