tac_contact_mask — 2D tactile op

Data kinds: imageregion

Call: fullseye.apply(img, "tac_contact_mask", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])

Usage

Contact region of a tactile frame by pseudo-reference background subtraction: `dev = |v - G_sigma(v)| with sigma = max(2, min(H,W)/6) (the low-frequency envelope stands in for the undeformed reference frame), thresholded at thr = 0.005 + 0.145*a gray levels, then cleaned with round(3*b) iterations of binary opening followed by binary closing (3x3, 8-connected). a = deviation threshold (sensitivity), b` = morphological cleanup strength. Returns a BINARY 0/1 float64 region of the input HxW; a perfectly flat (constant) frame has zero deviation everywhere and therefore yields an EMPTY mask.

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

Runnable examples (verified samples that actually call this op)

sim2real_and_alifepy -3.11 examples/sim2real_and_alife.py

Ops the type connects to (they accept region as input)

identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small

Same category (tactile)

tac_height_from_shading · tac_surface_normal · tac_pressure_proxy · tac_shear_field


*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.