Table 2.

Peak signal-to-noise ratio (PSNR) of comparison methods. $M_U$ , $M_D$, and $M_R$ represent the three kinds of networks described in Section 2.1. Yang91 is a standard training set that was firstly used by Yang [3].

Testing Images	Bicubic	SCSR	SRCNN “Jilin-1”	SRCNN “Yang91”	${\mathit{M}}_{\mathit{U}}$	${\mathit{M}}_{\mathit{D}}$	${\mathit{M}}_{\mathit{R}}$
Kabul (Afghanistan) (1)	31.88	34.15	26.85	34.03	35.78	36.23	35.82
Kabul (Afghanistan) (2)	34.48	36.70	27.59	36.56	38.08	38.37	38.09
Kabul (Afghanistan) (3)	36.65	38.61	27.76	38.68	39.60	39.88	39.67
Long Beach (USA) (1)	34.92	37.35	29.54	37.38	38.18	39.01	38.81
Long Beach (USA) (2)	37.96	40.83	30.84	40.53	41.23	42.09	41.74
Long Beach (USA) (3)	37.06	39.50	31.33	39.02	40.09	40.82	40.58
Tianjin (China) (1)	34.91	37.15	30.63	36.88	38.14	38.52	38.00
Tianjin (China) (2)	35.57	37.76	31.90	37.34	38.53	38.74	38.58
Durango (Mexico)	31.04	32.83	22.41	32.88	33.00	33.19	33.18