Perceptual Image Hashing Based on Multitask Neural Network

Table 2

Eight common content retention operations (attack operations) for images.

Operations	Parameter name	Values of parameter
Speckle noise	Variance	0.01, 0.05, 0.1, 0.2, 0.3
Scaling	Scaling ratio	0.2, 0.3, 0.4, 0.5, 1.5, 2, 4
Median filtering	Filter size	1, 3, 5, 7, 9, 11, 13, 15, 17, 19
Circle average filtering	Filter size	1, 5, 10, 15, 20, 25, 30, 35, 40
JPEG compression	Quality factor	1, 5, 10, 30, 50, 70, 90, 95
Rotation and cropping	Rotation angle	1, 2, 3, 4, 5, 6, 8, 10, 12
Gamma correction	Γ	0.55, 0.65, 0.75, 0.85, 0.95, 1.05, 1.15, 1.25, 1.35, 1.45
Gaussian filtering	Variance	0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.15, 0.2, 0.25