A Hidden Chaotic Attractor with an Independent Amplitude-Frequency Controller

Figure 9

Correlation and autocorrelation of R channel adjacent pixels of the pepper image and its ciphered image: (a) horizontal direction of the pepper image; (b) vertical direction of the pepper image; (c) diagonal direction of the pepper image; (d) horizontal direction of the pepper ciphered image; (e) vertical direction of the pepper ciphered image; (f) diagonal direction of the pepper ciphered image.