Secure and Efficient Image Retrieval over Encrypted Cloud Data

Table 2

Minimal Dunn index of each level.

Algorithm	Level of the Index Tree
	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
BBC	0.47	0.01	0.01	0.02	0.01	0.01	0.01	0.01	0.01	0.02		-	-	-	-	-
Bkmeans	0.47	0.01	0.02	0.01	0.02	0.02	0.02	0.03	0.04	0.24	0.73		-	-	-	-
Kmeans++	0.21	0.01	0.01	0.01	0.01	0.01	0.01	0.01	0.02	0.03	0.22	1.05		-	-	-
FSCL	0.47	0.04	0.05	0.06	0.07	0.1	0.15	0.19	0.23	0.38	0.28	0.58	0.62	0.66	0.95