A Multilevel Image Thresholding Method Based on Subspace Elimination Optimization

Table 4

Maximum entropy multilevel thresholding.

Image	Number of thresholds	Index	Exhaustion method	PSO	SSEO
Female	1	Entropy	8.8020	8.8015	8.8020
		Thresholds	101	100	100
		Time(s)	0.102574	0.112157	0.127748
		Variance of the Time		5.25562E-05	9.34983E-07
	2	Entropy	12.4804	12.4794	12.4803
		Thresholds	78 154	78 153	77 153
		Time(s)	1.260250	0.269593	0.227045
		Variance of the Time		2.69640E-02	6.11216E-06
	3	Entropy	15.6532	15.6440	15.6452
		Thresholds	56 105 157	55 105 158	56 104 160
		Time(s)	96.463659	0.465068	0.392787
		Variance of the Time		1.87901E-02	1.20258E-05
	4	Entropy	18.5869	18.5527	18.5644
		Thresholds	55 103 151 189	56 103 151 190	55 103 150 188
		Time(s)	8569.387408	1.410479	1.202857
		Variance of the Time		1.38343E+00	2.44926E-04
Jelly beans	1	Entropy	8.0707	8.0698	8.0707
		Thresholds	165	164	164
		Time(s)	0.100219	0.111406	0.125397
		Variance of the Time		9.62990E-05	5.44680E-06
	2	Entropy	11.5128	11.5097	11.5127
		Thresholds	104 167	104 166	103 166
		Time(s)	1.179629	3.592932	0.214063
		Variance of the Time		5.54159E+01	4.61903E-06
	3	Entropy	14.4455	14.4372	14.4398
		Thresholds	183 126 169	83 126 167	82 123 167
		Time(s)	98.183702	0.986705	0.395346
		Variance of the Time		1.40280E+00	6.48835E-06
	4	Entropy	17.0383	17.0220	17.0224
		Thresholds	63 94 131 169	62 94 131 167	62 93 130 167
		Time(s)	5906.410023	4.553701	1.213194
		Variance of the Time		3.14459E+01	2.5204E-05
San Diego	1	Entropy	8.9271	8.9270	8.9270
		Thresholds	135	134	134
		Time(s)	0.109754	0.112083	0.141757
		Variance of the Time		1.14090E-04	2.89662E-06
	2	Entropy	12.4042	12.4016	12.4041
		Thresholds	60 141	59 141	59 140
		Time(s)	1.227037	0.237745	0.244125
		Variance of the Time		5.27638E-03	1.02371E-05
	3	Entropy	15.5268	15.5216	15.5243
		Thresholds	57 113 164	57 112 164	55 110 163
		Time(s)	99.006925	0.453377	0.419603
		Variance of the Time		7.76216E-02	7.25335E-06
	4	Entropy	18.3835	18.3722	18.3729
		Thresholds	54 101 143 183	54 101 142 183	53 100 142 181
		Time(s)	6188.493106	2.247213	1.270564
		Variance of the Time		8.36189E+00	2.08382E-05
Sailboat	1	Entropy	8.9890	8.9890	8.9890
		Thresholds	125	125	124
		Time(s)	0.112816	0.117312	0.140577
		Variance of the Time		3.41402E-05	5.37697E-06
	2	Entropy	12.5254	12.5242	12.5254
		Thresholds	92 163	92 164	91 162
		Time(s)	1.257669	0.210157	0.242673
		Variance of the Time		3.78777E-03	7.77268E-06
	3	Entropy	15.5654	15.5611	15.5619
		Thresholds	73 120 170	73 120 169	73 120 170
		Time(s)	101.733913	0.609797	0.420331
		Variance of the Time		9.89256E-02	8.98313E-06
	4	Entropy	18.3682	18.3577	18.3582
		Thresholds	71 113 157 196	71 112 157 195	69 111 156 195
		Time(s)	6206.751312	2.575215	1.287299
		Variance of the Time		7.95833E+00	2.50911E-04