Improved Bat Algorithm Applied to Multilevel Image Thresholding

Table 2

Thresholds, objective function values, and time processing provided by the exhaustive search for Otsu’s method.

Images	𝐾	Threshold values	Objective function	Time (ms)
Barbara	2	82, 147	2608.610778507	39
	3	75, 127, 176	2785.163280467	89
	4	66, 106, 142, 182	2856.262131671	3014
	5	57, 88, 118, 148, 184	2890.976609405	100079
Living room	2	87, 145	1627.909172752	39
	3	76, 123, 163	1760.103018395	88
	4	56, 97, 132, 168	1828.864376614	2945
	5	49, 88, 120, 146, 178	1871.990616316	130397
Boats	2	93, 155	1863.346730649	38
	3	73, 126, 167	1994.536306242	89
	4	65, 114, 147, 179	2059.866280428	2931
	5	51, 90, 126, 152, 183	2092.775965336	75879
Goldhill	2	94, 161	2069.510202452	38
	3	83, 126, 179	2220.372641501	88
	4	69, 102, 138, 186	2295.380469158	2775
	5	63, 91, 117, 147, 191	2331.156597921	74674
Lake	2	85, 154	3974.738214185	39
	3	78, 140, 194	4112.631097687	89
	4	67, 110, 158, 198	4180.886161109	2613
	5	57, 88, 127, 166, 200	4216.943583790	73019
Aerial	2	125, 178	1808.171050536	46
	3	109, 147, 190	1905.410606582	103
	4	104, 134, 167, 202	1957.017965982	2670
	5	99, 123, 148, 175, 205	1980.656737348	99880