rft_generic — 2D `frequency` op

• Data kinds: image → image

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

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

rft_generic: 入力 → 出力

*The figure is the real output on a synthetic 128×128 input. Left: input, right: output (a non-image return value is shown as the value itself).*

Usage

A stand-in for the real Fourier transform (real FFT, RFFT). The implementation computes an ordinary complex FFT and returns the absolute value of the real part, `|Re F|`, normalized by its maximum -- it is not the half-size, real-only fast transform (data reduction exploiting symmetry) that HALCON's rft_generic actually computes. a and b are unused.

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

HALCON の `rft_generic`（画像の実数値高速フーリエ変換を計算する演算）に相当する近似 —— 出力される値の意味（実部の大きさの分布）は近いが、アルゴリズムそのものは異なる。

Detailed usage guide

• gallery2d_texture_freq 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.

rft_generic 0.40 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py

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

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

Same category (`frequency`)

lowpass · highpass · sk_butterworth · fft_image · power_real · power_byte · phase_rad · highpass_image

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

rft_generic — 2D frequency op