TABLE I.

Comparison of NLM and NLEM in Terms of PSNR and SSIM, at Noise Levels σ = 10, 20, …, 100 (Averaged Over 10 Noise Realizations). Same Parameters Used: S = 21, k = 7, and h = 10σ

Image	Method	PSNR (dB)
Checker	NLM	40.04	35.16	31.74	27.84	25.21	23.13	21.39	19.96	18.84	17.94
	NLEM	39.73	34.66	31.66	29.37	26.71	24.76	23.22	21.82	20.50	19.45
Circles	NLM	37.31	34.67	31.79	28.82	26.46	24.69	23.10	21.58	20.23	19.03
	NLEM	34.27	34.08	32.33	30.05	27.92	26.24	24.87	23.57	22.36	21.16
House	NLM	34.22	29.78	26.88	25.21	24.07	23.37	22.78	22.38	22.06	21.81
	NLEM	33.96	30.10	27.15	25.39	24.30	23.51	22.96	22.54	22.17	21.95
Barbara	NLM	32.37	27.39	24.93	23.52	22.64	22.04	21.62	21.29	21.07	20.88
	NLEM	32.11	27.75	25.26	23.84	22.90	22.29	21.83	21.48	21.20	21.01
Lena	NLM	33.24	29.31	27.40	26.16	25.24	24.54	24.04	23.66	23.34	23.06
	NLEM	33.15	29.45	27.61	26.40	25.53	24.84	24.31	23.90	23.53	23.24
		SSIM (%)
Checker	NLM	99.41	98.66	97.59	95.51	92.32	88.35	83.37	78.05	72.31	66.47
	NLEM	99.36	98.51	97.60	96.30	94.03	91.18	87.81	84.04	79.59	74.51
Circles	NLM	96.31	94.02	91.43	88.66	85.79	82.49	78.28	73.28	68.13	63.54
	NLEM	95.28	93.60	91.20	88.74	86.30	83.75	80.90	77.85	74.21	70.21
House	NLM	86.90	81.80	76.93	72.97	63.57	66.86	64.38	62.24	60.33	58.55
	NLEM	86.86	81.25	77.61	73.85	70.51	67.77	65.21	62.96	60.97	59.03
Barbara	NLM	89.95	79.48	71.32	65.20	60.79	57.42	54.64	52.58	50.78	49.27
	NLEM	90.25	80.38	72.49	66.48	62.04	58.57	55.64	53.45	51.50	49.86
Lena	NLM	86.95	80.41	76.45	73.42	70.80	68.45	66.46	64.66	62.94	61.32
	NLEM	87.06	80.57	76.77	73.97	71.50	69.21	67.20	65.32	63.52	61.81