Update data card: corrected eSAF gain stats and known-issues notes

README.md

@@ -107,8 +107,10 @@ and `..._ref.png` (each `.mat` holds the raw RF, the in-plane DAS, the metadata
 the eSAF output produced with the published algorithm `../matlab/saf/safrot_backproj.m`:
 in-plane DAS → `recon_3d` → `safrot_backproj`, f-number 45/8). A FWHM-vs-depth
 overview across probes is `sim_dataset_out/dataset_overview_r4.png`
-(`../sim/dataset_overview.m`). (`.mat`/`.hdf5` are git-ignored; the zea `.hdf5` set
-plus these `.mat`/`_ref.png` are delivered via Drive/S3.)
+(`../sim/dataset_overview.m`). The zea `.hdf5` acquisitions are **hosted on Hugging
+Face** at <https://huggingface.co/datasets/RyoMurakami/OpenH-RF-eSAF> (git-LFS; not
+committed to the GitHub code repo). The MATLAB `.mat`/`_ref.png` intermediates are
+reproducible from source and kept on lab storage.
 
 ## Dataset Quantification
 - **Acquisitions:** **195** = **190 simulated** + **5 measured phantom**.
@@ -166,13 +168,22 @@ images and a FWHM-vs-depth overview accompany the MATLAB `.mat` release
 - **Paired SAF label — on-axis targets (r0 = 0) do not narrow, by design.** eSAF
   refocuses the *rotational elevation smear*; a target sitting on the rotation axis has
   essentially no smear, so its `saf_bmode_volume` is not sharper than the input (arc-FWHM
-  gain < 1). This is expected physics, not a defect — the 40 on-axis cases (median gain
-  ~0.5×) are included so the pair covers the degenerate no-smear case. Off-axis targets
-  away from the 45 mm focus improve most (median ~1.35×; up to ~5–9×); targets at the
-  focal depth (~45 mm) and weak-elevation-focus probes (`efocus_deep_90`, `elev_unfocused`)
-  have little smear to recover. The eSAF back-projection uses a fixed elevational focus
-  of 45 mm; per-depth focus tuning (see `../docs/eSAF_focus_depth_study_JP.md`) can further
-  sharpen deep off-axis cases but was not applied here (single as-designed focus).
+  gain ≈ 1). This is expected physics, not a defect — the 40 on-axis cases (median gain
+  1.00×) are included so the pair covers the degenerate no-smear case. Off-axis targets
+  (n=120, median gain 1.75×, up to ~12×) and paired/oblique targets (n=30, median 3.71×)
+  improve clearly; targets at the focal depth (~45 mm) and weak-elevation-focus probes
+  (`efocus_deep_90`, `elev_unfocused`) have less smear to recover. Across all 195 cases,
+  median arc-FWHM gain is 1.36× (42 cases < 1×, mostly the on-axis/near-focus group above).
+  Arc-FWHM is measured on a **centred** reconstruction: the smear circle passes through both
+  the rotation axis and the target (not a circle centred on the rotation axis). The eSAF
+  back-projection uses a fixed elevational focus of 45 mm; per-depth focus tuning (see
+  `../docs/eSAF_focus_depth_study_JP.md`) can further sharpen deep off-axis cases but was
+  not applied here (single as-designed focus).
+- **Measured phantom depth window.** The real reflector bead sits **~4 mm off the rotation
+  axis** (not on-axis) and, for each scan, slightly deeper than the folder's nominal depth
+  label; labels are reconstructed over the interactively-identified reflector depth window
+  (not a naive nominal-depth ± 2 mm window), which matters because a mis-centred window can
+  pick up near-axis clutter instead of the actual bead.
 - **Simulated** data (Field II spatial-impulse-response model): realistic transducer
   field, but no tissue attenuation, aberration, multiple scattering, or electronic
   noise. Not a substitute for measured data.