gauss_filter — 2D smoothing op

Data kinds: imageimage

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

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

gauss_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):

gauss_filter: 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):

gauss_filter: 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

Smoothing via Gaussian blur (`scipy.ndimage.gaussian_filter, sigma 0.3+2.7*a). A stand-in for HALCON's gauss_filter` (Smooth using discrete Gauss functions.) -- HALCON uses a discrete Gaussian kernel (integer arithmetic), while this uses a continuous-Gaussian scipy implementation; it is an approximation, but the results are very close.

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

`a がシグマを 0.3〜3.0 の範囲で振る。b` は未使用。実装は

`gauss_image` と同一。

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_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.

gauss_filter 0.35 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

gallery2d_smoothing_rankpy -3.11 examples/gallery2d_smoothing_rank.py

poc_cell_countingpy -3.11 examples/poc_cell_counting.py

poc_document_scanpy -3.11 examples/poc_document_scan.py

poc_focus_stackingpy -3.11 examples/poc_focus_stacking.py

poc_gear_tooth_metrologypy -3.11 examples/poc_gear_tooth_metrology.py

poc_pv_thermal_surveypy -3.11 examples/poc_pv_thermal_survey.py

poc_sea_ice_concentrationpy -3.11 examples/poc_sea_ice_concentration.py

poc_search_sweep_widthpy -3.11 examples/poc_search_sweep_width.py

poc_solar_limb_darkeningpy -3.11 examples/poc_solar_limb_darkening.py

poc_vessel_networkpy -3.11 examples/poc_vessel_network.py

poc_white_balancepy -3.11 examples/poc_white_balance.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.