Robust Image Hashing Based on Cool and Warm Hue and Space Angle

Table 2

Hamming distance in different attacks.

Operation	Min	Max	Mean	SD
JPEG compression	4	67	20.4250	16.7912
Brightness adjustment	3	37	15.9000	8.7232
Contrast adjustment	2	26	11.8500	7.9092
Salt & pepper	12	83	28.8800	22.1384
Image resizing	6	74	20.9667	16.0763
3 × 3 Gaussian filter	5	51	20.3200	12.8372
Rotation	34	193	121.5250	45.8649
Watermark embedding	0	1	0.3000	0.4661
Gamma correction	12	60	31.9500	15.6692
Speckle	11	73	28.2000	20.2279