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

Table 5

The correlation coefficient of adjacent pixels of Skull image

Direction	Proposed		FRFT	ASFS	CENN
	Plaintext	Ciphertext
Horizontal	0.97762	0.0001	0.0018	0.0029	0.0195
Vertical	0.97742	0.0035	−0.0098	−0.0007	−0.0092
Diagonal	0.96126	−0.0026	0.0012	0.0009	0.0165