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docs/nodes/Blind Tip Estimate.md

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+# Blind Tip Estimate
+
+Blind tip estimation from a measured SPM image using the Villarrubia algorithm. Iteratively refines the tip shape using only the sharpest image features without knowing the true surface in advance.
+
+## Inputs
+
+| Name | Type | Required | Description |
+|------|------|----------|-------------|
+| field | DATA_FIELD | Yes | Measured SPM surface image |
+
+## Outputs
+
+| Name | Type | Description |
+|------|------|-------------|
+| tip | DATA_FIELD | Estimated tip shape (apex = maximum value, edges = 0) |
+| certainty | IMAGE | Map marking surface pixels where the tip was in unambiguous single contact |
+
+## Controls
+
+| Name | Type | Default | Description |
+|------|------|---------|-------------|
+| n_pixels | INT | 33 | Tip grid size in pixels (odd values only, 3–129) |
+| threshold | FLOAT | 0.0 | Noise floor in metres; increase if the estimated tip is unrealistically sharp |
+| method | dropdown | partial | partial: uses local maxima only (faster, needs sharp isolated features); full: uses all points above morphological opening (slower, more robust) |
+| use_edges | BOOLEAN | False | When enabled, also uses image edge pixels as refinement candidates |
+
+## Limitations
+
+- Requires sharp, isolated features on the surface for reliable results.
+- Output tip has the same pixel size as the input field; tip deconvolution requires matching pixel sizes.
+- Large tip sizes (n_pixels > ~65) or the full method on large images can be slow.
+- Equivalent to gwy_tip_estimate_partial / gwy_tip_estimate_full + gwy_tip_cmap.