(a) ODSs from the polynomial method with m = 5 with different scan frequencies at an excitation frequency of 111 Hz, (b) ODSs from the polynomial method with m = 7 with different scan frequencies at an excitation frequency of 335 Hz, (c) ODSs from the polynomial method with m = 8 with different scan frequencies at an excitation frequency of 688 Hz, and (d) ODSs from the polynomial method with m = 9 with different scan frequencies at an excitation frequency of 1193 Hz