tactile op• Data kinds: image → region
• 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])

*The figure is the real output on a synthetic 128×128 input. Left: input, right: output (a non-image return value is shown as the value itself).*
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.
• 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.
The program below has been verified to run (same input as the figure). In Studio's help this block becomes buttons that load and run it on the spot.
tac_contact_mask 0.50 0.50
▸ Load this pipeline · Load & run
• sim2real_and_alife — py -3.11 examples/sim2real_and_alife.py
region as input)identity · reg_erode · reg_dilate · reg_open · reg_close · fill_holes · select_largest · remove_small
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.