Figure 3 (a) A small 4 × 4 pixel image. (b) Moduli of the Fourier coefficients of Fig. 3(a); symmetry is visible around (h, k) = (0, 0). (c) Phases of the Fourier coefficients of Fig. 3(a); antisymmetry is visible around (h, k) = (0, 0). Maximum (minimum) values of moduli and phases are white (black).

© International Union of Crystallography 2007