dl_guided_filter — 2D smoothing op

• Data kinds: image → image

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

• HALCON equivalent: guided_filter (the HALCON reference is a useful guide to its meaning and parameters)

dl_guided_filter: 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.*

Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):

▸ dl_guided_filter: knob a sweep (docs site)

Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):

▸ dl_guided_filter: knob b sweep (docs site)

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

▸ dl_guided_filter: 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).*

Usage

A self-guided filter (guided filter, with the guide image being the input itself; torch implementation).

Edge-preserving smoothing that solves a linear regression q = a_lin*I + b_lin within a local window using box filters. a sweeps the window radius r over 1–5 (r = 1 + int(a*4)), and b sweeps the regularisation term eps over 0.001–0.051 (eps = 0.001 + 0.05*b; the larger it is, the stronger the smoothing and the weaker the edge preservation). A method known as a fast alternative to the bilateral filter; since the guide image is the input itself, it acts as self-guided edge-preserving smoothing. Corresponds to HALCON's guided_filter (performs guided filtering of an image), but it is an approximate implementation that does not necessarily give the same result.

Detailed usage guide

• gallery2d_smoothing_rank 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.

dl_guided_filter 0.35 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_smoothing_rank — py -3.11 examples/gallery2d_smoothing_rank.py

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

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

Same category (smoothing)

gaussian · mean_box · bilateral · unsharp · sk_tv · sk_wavelet · sk_rolling_ball · sk_nlm


*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.