Pseudorandom Number Generator Based on Three Kinds of Four-Wing Memristive Hyperchaotic System and Its Application in Image Encryption

Table 8

Correlation coefficients analysis.

Image	Direction	Plain image	Encrypted image	Ref. [57]	Ref. [79]	Ref. [80]	Ref. [81]
Lena	Horizontal	0.77724	−0.0045	−0.0031	−0.0084	−0.0124	0.0519
	Vertical	0.84858	0.0004	−0.0293	−0.0017	−0.0038	−0.0385
	Diagonal	0.7369	−0.0194	−0.0077	−0.0194	−0.0090	0.0046
Baboon	Horizontal	0.52256	−0.148	0.0224	—	—	—
	Vertical	0.51042	0.0060	0.0115	—	—	—
	Diagonal	0.41989	0.0069	−0.0025	—	—	—