tactile op• Data kinds: image → image
• Call: fullseye.apply(img, "tac_surface_normal", 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 actual output on a synthetic 128×128 input. Left: input, right: output. Point clouds are drawn as a top-down scatter (brightness = z), 1-D series as a line plot, volumes as the maximum-intensity projection along z, videos as the middle frame, complex images as magnitude; return values that are not pictures are shown as the values themselves.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ tac_surface_normal: knob a sweep (docs site)
Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):
▸ tac_surface_normal: knob b sweep (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ tac_surface_normal: other inputs (docs site)
*The 4th column is a colour (H,W,3) input. This op handles colour without crossing channels (it does not convolve the colour channel as a third spatial axis).*
Surface-normal z-component (slope map) from the shading gradients, using Horn's shape-from-shading normal parameterisation `n = (-p, -q, 1)/sqrt(1+p^2+q^2) so that nz = 1/sqrt(1+p^2+q^2) with p = gain*gx, q = gain*gy. Flat (uncontacted) gel gives nz = 1, steep indentation walls tend to 0, so the map is already a valid [0,1] encoding. a = gradient gain (1..21x -- how steep the shading is taken to be), b` = pre-smoothing sigma of the image (0..3) to tame sensor noise. Constant input -> all-ones (perfectly flat gel).
Blank frame (measured): feeding an image of uniform brightness makes every pixel foreground (1), regardless of the brightness. A frame that is blown out, occluded, or simply has no subject comes back as “100 % defective”, so test for uniformity upstream and reject such frames.
• 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_surface_normal 0.50 0.50
▸ Load this pipeline · Load & run
• sim2real_and_alife — py -3.11 examples/sim2real_and_alife.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
tactile)tac_contact_mask · tac_height_from_shading · 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.