Figure 6

Phase transform T{ χ }, in case when measured (solid black) and expected (dashed black) phase are close. The gray dotted line is the difference $\chi ={\widehat{\psi }}_{\mathit{\text{i}}\ell }\left[n\right]-{\psi }_{\mathit{\text{i}}\ell }^0\left[n\right]$ between both phases. The transform T{χ} (solid gray) produces a high value at frequency bins relevant for the harmonic sieve (assuming matching phases) and furthermore acts as an unwrapping function.