Heatmaps of Zernike aberration coefficients for a 80th-order approximation in full-pyramid representation (a) and in half-pyramid representation (b). To emphasize coefficients with small magnitudes, the coefficients are displayed on a bi-symmetric logarithmic scale [8]. In the full-pyramid representation, the signs of the coefficients are preserved, whereas in the half-pyramid representation, the magnitudes of the respective coefficient pairs are shown.