Noninvasive Remote Sensing Techniques for Infrastructures Diagnostics

Table 5

Comparison between the oscillation frequencies measured by HFI and GB microwave Radar with the relative percentage difference.

Drop	HFI (HZ)	GB microwave radar (Hz)	Relative percentage difference
1	4.7	4.8	2.1
2	4.5	4.6	2.2
3	4.5	4.5	0.0
4	4.6	3.8	17.4