texture op• Data kinds: image → image
• Call: fullseye.apply(img, "sk_lbp", 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.*
*The output is shown in a viridis-like pseudo-colour (dark purple = low, yellow = high) so that a field of quantities — distance, phase, orientation, depth — can be read.*
Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):
▸ sk_lbp: knob a sweep (docs site)
Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):
▸ sk_lbp: knob b sweep (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ sk_lbp: 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).*
LBP (Local Binary Pattern). A texture descriptor robust to illumination changes, built by comparing each pixel to its neighbors on a surrounding circle to form a binary code.
HALCON has no direct counterpart. The implementation is feature.local_binary_pattern(v, 8, 1+int(a*3)), normalised — the number of neighbour points P=8 is fixed, a sweeps the radius R over 1-4 (the larger the radius, the coarser the scale of texture picked up). ★b selects the encoding method ― b<0.60 gives 'default' (the default; not rotation-invariant), <0.75 gives 'ror', <0.90 gives 'uniform', and above that 'nri_uniform'.
Measured on real textures, a rotation-invariant encoding does not rescue anisotropic materials ― for brick / grass / gravel, the ratio of the deviation from itself under rotation to the minimum distance between materials is 9.64 / 0.17 / 0.19 with 'default' and 1.72 / 0.02 / 0.01 with 'uniform'. The 2 isotropic ones improve 10 times, yet brick does not drop below 1 (another material is closer than its rotated self). The rotation invariance of LBP concerns the cyclic shift of local patterns and cannot remove the orientation distribution of the material itself. Details = examples/poc_real_texture_invariance.py.
Value comparability (measured): the output is normalised by that image's own maximum (the output maximum is always 1.0, and scaling the input leaves the output unchanged). Values therefore cannot be compared across images — a feature of the same strength takes a different value depending on what the strongest feature in that image happens to be, and in an image holding only weak features the noise is lifted to 1.0. To compare across images, rescale by a common reference.
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.
• gallery2d_texture_freq family guide
• 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 canonical algorithm (author, year) and its uses are named in the family usage guide above.
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.
sk_lbp 0.50 0.50
▸ Load this pipeline · Load & run
• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py
• poc_real_texture_invariance — py -3.11 examples/poc_real_texture_invariance.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
texture)std_filter · local_bimodality · local_std · scale_select_std · bootstrap_std_error · structure_tensor_orientation · structure_tensor_coherence · gabor
*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.