texture op• Data kinds: image → image
• Call: fullseye.apply(img, "structure_tensor_orientation", 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):
▸ structure_tensor_orientation: knob a sweep (docs site)
Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):
▸ structure_tensor_orientation: knob b sweep (docs site)
On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):
▸ structure_tensor_orientation: 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).*
> This operator's description has not been translated yet. The original text follows as it is.
局所の縞の走る向き(構造テンソルの主軸)を `[0,1]` に写して返す。
`0 と 1 がともに水平、0.5` が垂直にあたる(向きは 180 度で一周するので、
`0 と 1` は同じ向き —— この出力を差分すると境目で偽の段差が出ることに注意)。
`a が微分前の平滑 sigma(0.5〜3.0 画素)、b が積分窓 rho`(1.0〜8.0 画素)。
`rho` は「どれくらいの広さで向きが揃っているとみなすか」で、繊維や研磨目のピッチより
大きく取る。
適用条件: 向きが定義できるのは勾配が構造的に偏っている所だけ。テンソルの
異方度が跡に対して `1e-6` を下回る画素(平坦面・等方な雑音)は「向き未定義」として
`0.5 を返す —— ここで床を置かないと、一様な面で丸め屑が arctan2` に増幅されて
明るさを 0.01 変えただけで向きが一斉に反転する。向きの確からしさは
`structure_tensor_coherence` で別に測ること。
用途: 繊維強化材の繊維配向、圧延・研磨の条痕方向、木目、結晶粒の伸長方向。
HALCON に対応する単体 op は無い。
• 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.
structure_tensor_orientation 0.50 0.50
▸ Load this pipeline · Load & run
• degenerate_inputs — py -3.11 examples/degenerate_inputs.py
• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.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_coherence · gabor · sk_frangi
*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.