33 lines
1.5 KiB
Markdown
33 lines
1.5 KiB
Markdown
# Blind Tip Estimate
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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.
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## Inputs
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| Name | Type | Required | Description |
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|------|------|----------|-------------|
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| field | DATA_FIELD | Yes | Measured SPM surface image |
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## Outputs
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| Name | Type | Description |
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|------|------|-------------|
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| tip | DATA_FIELD | Estimated tip shape (apex = maximum value, edges = 0) |
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| certainty | IMAGE | Map marking surface pixels where the tip was in unambiguous single contact |
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## Controls
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| Name | Type | Default | Description |
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|------|------|---------|-------------|
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| n_pixels | INT | 33 | Tip grid size in pixels (odd values only, 3-129) |
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| threshold | FLOAT | 0.0 | Noise floor in metres; increase if the estimated tip is unrealistically sharp |
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| method | dropdown | partial | partial: uses local maxima only (faster, needs sharp isolated features); full: uses all points above morphological opening (slower, more robust) |
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| use_edges | BOOLEAN | False | When enabled, also uses image edge pixels as refinement candidates |
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## Notes
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- Requires sharp, isolated features on the surface for reliable results.
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- Output tip has the same pixel size as the input field; tip deconvolution requires matching pixel sizes.
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- Large tip sizes (n_pixels > ~65) or the full method on large images can be slow.
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- Equivalent to gwy_tip_estimate_partial / gwy_tip_estimate_full + gwy_tip_cmap.
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