Figure 5.

Diagram of a single FPM reconstruction algorithm iteration n. It starts by initializing a high-resolution image estimate o₀(r), which was an interpolated experimental brightfield image. For each illumination angle, a region of the high-resolution estimate spectrum, corresponding to illumination angle i is low-pass filtered to produce an estimate of the low-resolution image: ${\mathrm{\psi }}_{\mathit{n}}^{(\mathit{i})}$. A new estimate, ${\phi }_{\mathit{n}}^{(\mathit{i})}$ is obtained by replacing the amplitude of ${\mathrm{\psi }}_{\mathit{n}}^{(\mathit{i})}$ with the amplitude of the demosaiced recorded image, $\sqrt{\mathit{I}}$, while retaining the phase of ${\mathrm{\psi }}_{\mathit{n}}^{(\mathit{i})}$. The low-resolution spectrum is added into the high-resolution spectrum using eqs (6) and (7) to yield the updated object spectrum and pupil functions O_n+1(k) and P_n+1(k). The whole process continues till spectrum regions corresponding to all illumination angles are updated. An example of the reconstructed spectrum is shown at the bottom of the figure.