Table 4: The quantitative comparison results of average PSNR/SSIM for  $2 \times$ ,  $3 \times$ ,  $4 \times$  image SR. The best results are highlighted in black bold and the second best is in underline.
Scale	Method	Params	Set5 PSNR/SSIM	Set14 PSNR/SSIM	B100 PSNR/SSIM	Urban100 PSNR/SSIM	Manga109 PSNR/SSIM	DIV2K valid PSNR/SSIM
2×	FSRCNN [10]	24.5K	33.09/0.9180	30.02/0.8625	29.44/0.8396	26.77/0.8320	30.29/0.9172	32.18/0.8989
SamplingAug [39]	24.5K	34.71/0.9414	31.24/0.8942	30.51/0.8766	27.83/0.8667	32.28/0.9452	33.46/0.9225
UDN [31]	24.5K	34.79/0.9412	31.29/0.8940	30.50/0.8758	27.81/0.8660	32.34/0.9448	33.47/0.9223
BSPA (ours)	24.5K	34.80/0.9420	31.27/0.8943	30.54/0.8772	27.86/0.8682	32.27/0.9454	33.50/0.9232
EDSR基礎 [23]	1.4M	37.58/0.9590	33.15/0.9140	31.89/0.8959	30.89/0.9156	37.57/0.9745	35.54/0.9411
SamplingAug [39]	1.4M	37.65/0.9591	33.25/0.9146	31.96/0.8969	31.15/0.9184	37.76/0.9747	35.66/0.9420
UDN [31]	1.4M	37.60/0.9590	33.12/0.9137	31.89/0.8960	30.93/0.9160	37.67/0.9747	35.56/0.9411
BSPA (ours)	1.4M	37.70/0.9594	33.27/0.9149	31.96/0.8968	31.18/0.9185	37.78/0.9752	35.69/0.9420
RCAN [52]	15.4M	37.71/0.9596	33.31/0.9151	31.99/0.8976	31.41/0.9213	37.93/0.9755	35.74/0.9428
SamplingAug [39]	15.4M	37.89/0.9599	33.47/0.9161	32.05/0.8978	31.69/0.9240	38.39/0.9762	35.91/0.9436
UDN [31]	15.4M	37.86/0.9601	33.43/0.9162	32.05/0.8983	31.65/0.9239	38.15/0.9760	35.89/0.9440
BSPA (ours)	15.4M	37.94/0.9603	33.58/0.9181	32.14/0.8994	31.98/0.9272	38.49/0.9767	36.06/0.9449
3×	FSRCNN [10]	24.5K	29.91/0.8520	27.26/0.7625	27.07/0.7309	24.34/0.7237	26.46/0.8318	29.38/0.8221
SamplingAug [39]	24.5K	31.02/0.8794	28.13/0.7978	27.69/0.7657	24.97/0.7574	27.58/0.8632	30.18/0.8476
UDN [31]	24.5K	31.21/0.8825	28.27/0.8018	27.75/0.7701	25.03/0.7613	27.78/0.8682	30.28/0.8504
BSPA (ours)	24.5K	31.13/0.8823	28.20/0.8008	27.74/0.7693	25.01/0.7611	27.65/0.8680	30.24/0.8498
EDSR基礎 [23]	1.6M	33.79/0.9219	29.91/0.8340	28.83/0.7979	27.21/0.8305	32.30/0.9345	31.87/0.8787
SamplingAug [39]	1.6M	33.85/0.9223	30.00/0.8353	28.86/0.7987	27.35/0.8344	32.55/0.9361	31.95/0.8800
UDN [31]	1.6M	33.75/0.9216	29.89/0.8335	28.82/0.7978	27.15/0.8298	32.33/0.9344	31.85/0.8786
BSPA (ours)	1.6M	33.97/0.9237	30.03/0.8361	28.89/0.7999	27.42/0.8359	32.60/0.9372	31.99/0.8807
RCAN [52]	15.6M	33.70/0.9206	29.87/0.8328	28.78/0.7970	27.11/0.8274	32.10/0.9320	31.81/0.8776
SamplingAug [39]	15.6M	34.15/0.9247	30.20/0.8390	28.96/0.8011	27.78/0.8439	33.13/0.9403	32.14/0.8830
UDN [31]	15.6M	34.26/0.9255	30.22/0.8397	29.00/0.8026	27.80/0.8448	33.05/0.9407	32.23/0.8846
BSPA (ours)	15.6M	34.35/0.9268	30.31/0.8413	29.07/0.8044	28.15/0.8519	33.35/0.9432	32.36/0.8867
4×	FSRCNN [10]	24.5K	28.14/0.7960	25.91/0.6979	25.94/0.6660	23.14/0.6537	24.71/0.7705	28.00/0.7710
SamplingAug [39]	24.5K	29.02/0.8242	26.52/0.7266	26.37/0.6936	23.59/0.6813	25.40/0.7950	28.57/0.7919
UDN [31]	24.5K	29.11/0.8250	26.53/0.7272	26.37/0.6936	23.58/0.6811	25.45/0.7965	28.60/0.7927
BSPA (ours)	24.5K	29.04/0.8241	26.51/0.7261	26.35/0.6921	23.55/0.6790	25.40/0.7957	28.56/0.7912
EDSR基礎 [23]	1.5M	31.57/0.8861	28.22/0.7723	27.31/0.7268	25.27/0.7574	29.27/0.8902	29.97/0.8265
SamplingAug [39]	1.5M	31.72/0.8876	28.29/0.7735	27.34/0.7281	25.39/0.7624	29.57/0.8936	30.04/0.8279
UDN [31]	1.5M	31.44/0.8833	28.15/0.7707	27.27/0.7257	25.17/0.7539	29.05/0.8866	29.90/0.8253
BSPA (ours)	1.5M	31.80/0.8897	28.37/0.7765	27.40/0.7312	25.53/0.7685	29.72/0.8972	30.13/0.8312
RCAN [52]	15.6M	31.92/0.8910	28.38/0.7763	27.40/0.7306	25.54/0.7684	29.77/0.8982	30.16/0.8311
SamplingAug [39]	15.6M	32.00/0.8915	28.48/0.7788	27.47/0.7323	25.80/0.7771	30.17/0.9027	30.23/0.8331
UDN [31]	15.6M	31.91/0.8907	28.45/0.7773	27.45/0.7311	25.70/0.7721	29.86/0.8989	30.21/0.8321
BSPA (ours)	15.6M	32.18/0.8943	28.56/0.7807	27.54/0.7348	26.02/0.7839	30.34/0.9060	30.39/0.8363