xmh_pftas — 2D `texture-feature` op

• Data kinds: image → feature

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

xmh_pftas: 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.*

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

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

Usage

Variance of the 54-dimensional PFTAS (parameter-free threshold adjacency statistics, mahotas.features.pftas) feature vector. A texture feature that aggregates histograms counting adjacent-pixel intensity relationships using a parameter-free threshold.

a, b are unused. Measured on 2026-09-02: using the mean of the 54 dimensions, owing to the nature of normalised histograms it takes almost only values of integer/54, and across 12 images (4 sizes x 3 contents) there were only 2 distinct values (effectively a constant). With the variance, the spread of the distribution remains and changes from image to image, so the variance is adopted here.

Detailed usage guide

• gallery2d_features 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.

xmh_pftas 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_features — py -3.11 examples/gallery2d_features.py

Ops the type connects to (they accept `feature` as input)

identity · feature_to_img

Same category (`texture-feature`)

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*Provenance: ops.py — 2D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

xmh_pftas — 2D texture-feature op