**5. Conclusions**

Based on digital image processing technology, this paper presents a novel method for structural overall deformation monitoring. Using the proposed method, a series of deformation measurement experiments are carried out on a steel–concrete composite beam, and the main conclusions are as the following:


some parts of the measuring structures are obscured. Under such a situation, the postprocessing method, such as the fitting, can be applied to obtain the approximation data of the blocked parts.

**Author Contributions:** X.C. conceived this study, designed the computational algorithms, wrote the program code, and wrote the manuscript. Z.Z. proposed some valuable suggestions and guided the experiments. G.D., X.D. acquired the test images and performed the experiments. X.J. carried out the measurements and analyzed the experimental data.

**Funding:** This research was funded by the National Natural Science Foundation Projects (Grant No.: 51778094, 51708068).

**Acknowledgments:** Special thanks to J.L. Heng at the Southwest Jiaotong University.

**Conflicts of Interest:** The authors declare no conflict of interest.
