Cost-Effective and Ultraportable Smartphone-Based Vision System for Structural Deflection Monitoring

Table 1

Results of displacement measurement by smartphone and dial gauges.

Loading and unloading		Target 1			Target 2			Target 3
Stages	Load(N)	SP (mm)	DG (mm)	Error	SP (mm)	DG (mm)	Error	SP (mm)	DG (mm)	Error
Before loading	0	0.002	0.000		0.003	0.000		0.001	0.000
First loading	9.8	2.732	2.742	0.36%	1.404	1.409	0.35%	0.301	0.304	0.99%
Second loading	29.4	7.291	7.306	0.20%	3.738	3.766	0.74%	0.818	0.819	0.12%
Third loading	34.3	8.437	8.465	0.33%	4.321	4.361	0.92%	0.947	0.949	0.21%
Fourth loading	39.2	9.597	9.608	0.11%	4.916	4.951	0.71%	1.081	1.079	0.19%
First unloading	34.3	8.474	8.484	0.12%	4.342	4.376	0.78%	0.953	0.954	0.10%
Second unloading	29.4	7.35	7.349	0.01%	3.776	3.794	0.47%	0.821	0.827	0.73%
Third unloading	9.8	2.803	2.785	0.65%	1.444	1.447	0.21%	0.314	0.312	0.64%
Fourth unloading	0	0.005	0.003		0.002	0.001		0.001	0.001