A New V-Net Convolutional Neural Network Based on Four-Dimensional Hyperchaotic System for Medical Image Encryption

Table 4

The correlation coefficient of adjacent pixels of Lena image

Direction	Proposed		FRFT	ASFS	CENN
	Plaintext	Ciphertext
Horizontal	0.97423	−0.0006	0.0020	−0.0003	−0.0009
Vertical	0.98592	0.0024	0.0099	0.0105	0.0139
Diagonal	0.96275	0.0002	−0.0049	0.0078	−0.0006