## 5 Conclusions  
In this research, a novel method of slice template matching model is proposed to measure the full-field temporal-spatial deformation of slender structures, and the indoor experiment shows that STMM is proved to be of high precision and has good application prospects in future bridge health monitoring. The following conclusions can be drawn:  
(1) The slice template matching model proposed can effectively measure the full-field temporal-spatial deflection of structure with large slender ratio, and an indoor experiment was designed and carried out to validate the STMM method. Experiment results show that the displacement measurement result of the STMM agreed well with the theoretical results and laser ranger measurement results.  
(2) Experiment results demonstrated that the temporal full-field displacement measurement error of the STMM is not constant and changes both spatially and temporally, and the maximum displacement measurement error is 0.47 pixels. Transiently, the RMSE  
Figure 21: Gray value distribution of the 3761 th column mask and transversal region in different frames.  
\begin{table}
\begin{tabular}{c c c} \hline
**Source of Data** & **Correlation Coefficient** & **Coefficient of Determination** \\ \hline Reference [17] & 0.9689–0.9887 & 0.9368–0.9775 \\ This Paper & 0.9994 & 0.9986 \\ \hline \end{tabular}
\end{table}
Table 3: Correlation of mid-span displacement time curves of STMM and laser ranger.  
of full-field simply supported beam deflection curve from the STMM measurement and theoretical results is about 0.169 mm. For single points, the correlation coefficient and the determination coefficient of displacement-time history curves of the STMM and laser ranger are 0.9994 and 0.9986, respectively.  
(3) Gray distribution analysis of the transversal region reveals that the STMM is also greatly influenced by the brightness inconstancy caused by optical environment variation, and further study should be carried out to investigate the mechanism of the measurement error and control in complex weather conditions and illumination environments, or structures with complex inelastic mechanical properties and large deformations, for example, cables, bars, and piers.  
Conceptualization and methodology, J.Z. and H.L.; validation, Y.S. and J.H.; formal analysis, J.Z.; investigation, H.L. and Z.Z.; resources, J.Z. and Z.Z.; data curation, J.Z. and Y.S.; writing--original draft preparation, J.Z. and H.L.; writing--review and editing, J.Z. and H.L.; Y.S., supervision, J.Z. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Natural Science Foundation of China (Grant No. 51778094), the National Natural Science Foundation of China (Grant No. 51708068), the Joint Training Base for Postgraduate Construction Project of Chongqing (Grant No. JDLHPYJD2020019), and the Postgraduate Tutor Team Construction Project of Chongqing (Grant No. JDSTD2022003). We also acknowledge the State Key Laboratory of Mountain Bridge and Tunnel Engineering for providing experimental equipment.  
Not applicable.  
The data that support the findings of this study are available from the corresponding author upon reasonable request.  
Author [PERSON] was employed by the company China Merchant Chongqing Communication Research & Design Institute Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.