Figure 7: Texture-enhancement capability comparison. (a) original image, (b) the nonlinearly enhancing the high-frequency components by Butterworth filter, (c) general fractional differentiation of order, (d) enhanced image by FDD operator of order, (e) original image, (f) the nonlinearly enhancing the high-frequency components by Butterworth filter, (g) general fractional differentiation of order, (h) enhanced image by FDD operator of order, (i) original image, (j) the nonlinearly enhancing the high-frequency components by Butterworth filter, (k) general fractional differentiation of order, (l) enhanced image by FDD operator of order, (m) original image, (n) the nonlinearly enhancing the high-frequency components by Butterworth filter, (o) general fractional differentiation of order, and (p) enhanced image by FDD operator of order.