Otsu Based Optimal Multilevel Image Thresholding Using Firefly Algorithm

Table 2

Comparison of the standard deviation, PSNR, SSIM, and CPU time obtained for test images.

Test images	𝑚	Standard deviation			PSNR (dB)			SSIM			CPU time (sec)
		BDFA	LFFA	FA	BDFA	LFFA	FA	BDFA	LFFA	FA	BDFA	LFFA	FA
Barbara	2	0.00914	0.02582	0.01457	20.0652	25.1241	23.0627	0.8068	0.7540	0.7882	100.46	26.15	47.05
	3	0.07482	0.06925	0.06679	22.0239	25.2267	24.1197	0.8371	0.8201	0.8300	163.05	41.26	43.14
	4	0.50224	0.62528	0.27874	21.7727	23.1895	22.0257	0.8553	0.8227	0.8285	187.25	57.31	50.42
	5	0.62903	0.80425	0.70422	24.8064	24.9632	25.0159	0.8368	0.8113	0.8328	258.15	45.25	73.02
Lena	2	0.02891	0.16251	0.07539	23.2027	27.1066	25.1176	0.8208	0.8011	0.8116	102.36	18.02	25.14
	3	0.04903	0.27180	0.13850	20.9014	22.0823	20.9964	0.8489	0.8246	0.8310	142.47	31.78	61.03
	4	0.31176	0.52319	0.38196	24.1167	25.2476	25.5752	0.8606	0.8165	0.8206	204.52	56.23	71.32
	5	0.58319	0.83251	0.61698	23.2251	24.1466	23.2257	0.8847	0.8542	0.8729	291.02	69.22	108.13
Cameraman	2	0.00176	0.27810	0.07972	25.2568	25.7741	25.8820	0.8258	0.7736	0.8211	104.15	37.28	42.05
	3	0.11874	0.29826	0.31709	23.2942	26.0523	24.0368	0.8432	0.7302	0.8400	131.42	51.35	60.15
	4	0.73652	0.52111	0.37073	25.1117	27.2476	25.8852	0.8478	0.7533	0.8218	128.26	58.13	62.34
	5	0.90362	0.70728	0.74130	26.0004	27.1168	26.4773	0.8633	0.8154	0.8206	142.43	55.28	70.51
Living Room	2	0.03782	0.12671	0.19542	22.0778	22.9625	23.1843	0.8004	0.7699	0.7804	305.35	118.15	136.04
	3	0.07293	0.16729	0.21073	20.2699	22.9952	21.0424	0.8105	0.7811	0.7915	461.55	132.03	130.33
	4	0.38791	0.50981	0.49611	24.9426	26.0731	25.5817	0.8422	0.8102	0.8200	604.46	146.21	172.49
	5	0.82522	0.92351	0.99218	26.0774	26.4426	26.9936	0.8259	0.8246	0.8216	822.50	165.15	190.22
Mandrill	2	0.26681	0.38199	0.28541	23.1159	24.0052	24.1111	0.8077	0.7745	0.7835	89.37	52.11	54.27
	3	0.27916	0.51029	0.39510	21.0002	22.1842	21.2943	0.8322	0.8004	0.8125	114.50	51.58	64.03
	4	0.63441	0.73416	0.73170	24.1883	25.2952	24.7160	0.8421	0.7953	0.8386	172.24	59.13	72.44
	5	0.83551	0.91282	0.90525	21.2683	22.0673	23.0662	0.8257	0.8104	0.7993	166.39	71.35	69.51
Jet	2	0.43203	0.69100	0.28023	23.9864	24.1578	24.0622	0.8414	0.8011	0.8268	79.03	43.35	41.50
	3	0.55871	0.69261	0.63321	21.8552	21.9994	22.0523	0.8528	0.7793	0.8280	82.33	51.29	48.04
	4	0.58352	0.83515	0.70527	26.0316	26.1481	26.1963	0.8234	0.7922	0.8003	97.15	74.22	84.52
	5	0.62253	0.92614	0.88038	25.3806	26.0437	25.5280	0.8943	0.8317	0.8552	133.07	94.25	77.06
Boat	2	0.00256	0.13872	0.02923	23.7731	24.9962	25.0063	0.8018	0.7935	0.7825	59.35	42.55	51.12
	3	0.02361	0.20018	0.06377	20.2579	21.2579	22.0774	0.8280	0.7847	0.7899	63.19	50.32	46.24
	4	0.18389	0.41993	0.21950	21.6589	23.1843	24.1116	0.8146	0.8003	0.8002	89.04	62.13	70.13
	5	0.20871	0.61923	0.37424	25.0227	26.7428	25.8125	0.8593	0.8331	0.8236	107.23	71.35	81.30
Zebra	2	0.10198	0.41092	0.20850	26.0424	27.3566	26.9431	0.8405	0.7999	0.8332	125.31	48.01	72.52
	3	0.18378	0.57708	0.31114	27.1157	27.8841	27.3215	0.8305	0.8110	0.8206	91.26	50.19	42.16
	4	0.18992	0.72119	0.50019	25.6428	27.0053	25.9092	0.8288	0.7845	0.8005	124.20	61.34	71.24
	5	0.39346	0.90371	0.74930	25.7431	27.1579	26.0853	0.8500	0.8003	0.8367	152.43	73.15	80.26
Snake	2	0.00278	0.21309	0.04859	25.0723	25.1589	26.2786	0.8267	0.7945	0.8025	110.52	59.21	61.25
	3	0.07820	0.40192	0.15428	20.6437	20.6318	21.2578	0.8725	0.8264	0.8226	136.11	62.25	82.19
	4	0.13891	0.51223	0.28420	24.0628	24.9132	24.3337	0.8259	0.8077	0.8024	131.35	71.39	59.18
	5	0.20182	0.98801	0.49110	22.1118	23.0075	22.9524	0.8551	0.8205	0.8366	148.52	83.11	93.40
Fish	2	0.00991	0.34992	0.00163	20.0732	22.7737	21.9966	0.8049	0.7883	0.7832	98.01	44.27	54.17
	3	0.01831	0.71027	0.02679	24.0224	24.8512	25.0222	0.8166	0.7935	0.7903	105.39	51.44	67.35
	4	0.01926	0.79926	0.03922	22.7874	24.1817	23.1570	0.8552	0.8154	0.8277	129.56	41.35	82.05
	5	0.28919	0.90172	0.01749	25.0861	25.1119	25.0063	0.8729	0.8553	0.8260	131.03	77.51	90.18
Star Fish	2	0.02813	0.11162	0.01944	20.0004	22.5775	21.7269	0.8428	0.8032	0.8246	91.43	58.51	45.44
	3	0.06321	0.30992	0.03792	20.4882	21.1583	22.0133	0.8333	0.8004	0.8022	116.30	58.03	77.02
	4	0.21739	0.70018	0.13270	21.0632	22.2257	24.5721	0.8510	0.7994	0.8365	108.39	44.00	72.45
	5	0.51910	0.92732	0.42680	23.1567	25.5004	26.1489	0.8371	0.8177	0.8024	111.59	81.25	69.30
Sailor	2	0.12763	0.93471	0.37703	20.7738	22.1268	21.2311	0.8248	0.8210	0.7937	93.51	46.29	55.03
	3	0.28711	0.90182	0.52893	25.9125	25.9984	26.1489	0.8537	0.8422	0.8325	141.38	51.49	50.17
	4	0.48291	0.98271	0.72279	23.3532	23.9552	25.1362	0.8440	0.8001	0.8228	127.51	70.14	68.47
	5	0.71032	0.99013	0.93321	24.0284	25.0061	24.9958	0.8206	0.7990	0.7993	130.09	65.39	82.37