Automatic Traffic Data Collection under Varying Lighting and Temperature Conditions in Multimodal Environments: Thermal versus Visible Spectrum Video-Based Systems

Table 6

Vehicle speed performance for different lighting conditions—thermal and regular video.

Lighting condition	Thermal video			Regular video
	Calibration model			Calibration model
Daytime
Overcast			0.91			0.95
Sun, little shadow	= + 2.91		0.96	= + 1.77		0.92
Sun, slight shadows	= + 2.50		0.93	= + 5.75		0.90
Sun, strong shadows	= + 0.20		0.88			0.56
Nighttime
High visibility	= + 4.49		0.93	= + 0.01		0.92
Medium visibility	= + 2.45		0.86	= + 4.14		0.46
Low visibility	= + 0.17		0.97	= + 0.83		0.93
Lighting condition	Thermal video			Regular video
	MRE	RAE	RPE	MRE	RAE	RPE
Daytime
Overcast	0.067	0.058	0.067	0.059	0.001	0.059
Sun, little shadow	0.106	0.116	0.045	0.069	0.071	0.062
Sun, slight shadows	0.103	0.105	0.047	0.226	0.242	0.063
Sun, strong shadows	0.061	0.005	0.061	0.108	0.053	0.097
Nighttime
High visibility	0.150	0.151	0.047	0.051	0.000	0.051
Medium visibility	0.104	0.082	0.072	0.150	0.138	0.104
Low visibility	0.036	0.026	0.033	0.060	0.005	0.059