A Robust Coverless Image Steganography Algorithm Based on Image Retrieval with SURF Features

Table 4

Types of attacks performed on images in experiments and their parameters.

Image processing	The specific parameters
JPEG compression	The quality factors Q: 10%, 50%, and 90%
Gauss noise	The mean μ: 0, the variance σ: 0.001 and 0.005
Salt and pepper noise	The mean μ: 0, the variance σ: 0.001 and 0.005
Speckle noise	The mean μ: 0, the variance σ: 0.001 and 0.005
Gauss low-pass filtering	The window size: 3 × 3
Mean filtering	The window size: 3 × 3
Median filtering	The window size: 3 × 3
Centered cropping	Ratio: 20% and 50%
Edge cropping	Ratio: 10% and 20%
Rotation	Rotation angles: 10°, 30°, and 50°
Translation	In holidays: (80, 50), (160, 100), and (320, 200)
	In ImageNet, Caltech-256: (16, 10), (32, 20), and (40, 25)
Scaling	Ratio: 0.5, 0.75, 1.5, and 3
Color histogram equalization	None
Gamma correction	Factor: 0.8