Table 1.

Comparison between CW THz imaging system and TPI system [61].

Parameter	CW THz Imaging System	TPI System
Cost	USD 50,000–150,000	USD 300,000–1,000,000
System complexity	Data	Data
Data complexity	Low	High
Weight	About 2 kg	About 300 kg
Information	Transmitted energy	Magnitude information; Phase information; Shape of pulse; Transmission time; Absorption spectrum; Depth
Speed	0.005 s per point 1 mm step size	20–0.05 s per waveform