Is the second oscillation (where it goes from blue to red and then back to blue again) expected? This does not seem to be modeled, even if I select a resolution range in which it is included in the data:
We’d like to take a look into this phenomenon, and it would help if we had data that can reproduce this. If either of you are willing to confidentially share data with the CryoSPARC team (and still have access to the data causing the phenomenon!), please let me know in this thread or via DM, and I can follow-up with further instructions.
After looking more closely at the data, I believe this is a benign plotting artefact. The “data for odd terms” plots (where the multiple oscillations show) hold the per-pixel estimated phase residual in radians. So it’s the per-pixel independent estimate of the phase residual modulo 2pi, because phases are only uniquely determined up to additions of 2*pi. So where the second band of blue/red values start, that’s actually the phase wrapping around from pi to -pi (discontinuously).
The “fit” plots show the regression results of the phase residual (regressing across all pixels in the image) as per Zivanov et al. Here they vary continuously over frequency (by construction of the regression, because the phase is expressed as a linear combination of continuous zernicke polynomials) and aren’t limited to [-pi, pi], so no wrapping happens when they exceed this range.
Here’s a scatterplot of the raw data (“data for odd terms”) vs. the predicted phase (“fit”) and this confirms that they are the same +/- 2pi, so still indicating a strong agreement between data and fit.