xsitk_curvature_flow — 2D extra op

Data kinds: imageimage

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

xsitk_curvature_flow: input → output

*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):

xsitk_curvature_flow: knob a sweep (docs site)

*Knob b does not change the output (measured: identical at 0.1 / 0.5 / 0.9).*

On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):

xsitk_curvature_flow: other inputs (docs site)

*No colour (H,W,3) input is shown: this op treats the colour channel as a third spatial axis (it crosses channels). Call it per channel.*

Usage

Curvature flow smoothing (SimpleITK `CurvatureFlow`). A nonlinear diffusion that blurs the image at a speed proportional to the curvature of its contour lines; straight edges tend to be preserved while rounded details disappear first.

> The detailed description below is the original text — the summary and the headings are translated.

`a は反復回数(1+int(a*8) で 1〜9 回)を振る —— 増やすほど強く平滑化される。時間刻みは 0.0625 固定。b` は未使用。出力は [0,1] にクリップ。

Border handling: mirror repeating the edge pixel (d c b a | a b c d — scipy's default `reflect) (measured; tools/impl2/border_probe.py`).

Detailed usage guide

gallery2d_color_artistic family guide

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.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Try it in Studio

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.

xsitk_curvature_flow 0.50 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

gallery2d_color_artisticpy -3.11 examples/gallery2d_color_artistic.py

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

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (extra)

xsitk_minmax_curv_flow · xsitk_curv_aniso_diff · xsitk_laplacian_sharpen · xsitk_grayscale_fillhole · xsitk_grayscale_grindpeak · xsitk_opening_by_recon · xsitk_closing_by_recon · xsitk_signed_maurer_dist


*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.