Local Negative Base Transform and Image Scrambling

Table 4

GDD and correlation values.

Method name	rounds	GDD	Correlation values
			Horizontal	Vertical	Diagonal
Original image	∖	∖
2D Arnold [10]
Discrete Baker map [26]
Sub-affine [27]
CA [15]
Fibonacci-Q [10]
Hilbert curve [19]
Magic cube [9]
2×2 sampling [28]
LNBT-1
LNBT-2
LNBT-3

Remark: visually, the scrambling performance of the third round of 2x2 sampling transform is best, and the 29th round of LNBT-1 has the best scrambling effect. Figures (i) and (j) are the scrambled images of the third round of 2x2 sampling transform and of the 29th round of LNBT-1, respectively.