frequency op• Data kinds: image → image
• Call: fullseye.apply(img, "fft_generic", a=0.5, b=0.5) (the 2-D model is one image plus two scalar knobs a,b∈[0,1])
• HALCON equivalent: fft_generic (the HALCON reference is a useful guide to its meaning and parameters)
*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).*
Returns the log-compressed amplitude spectrum of the image's Fourier transform (`log1p(|F|) normalized by its maximum). The center corresponds to low-frequency components and the periphery to high-frequency components (already fftshift`-ed). a and b are unused.
> The detailed description below is the original text — the summary and the headings are translated.
HALCON の `fft_generic（順変換・逆変換・実数/複素数など多数のモードを持つ汎用 FFT 演算）のうち、順方向の振幅スペクトル表示だけを実装した近似 —— 逆変換や位相成分などの他モードは別 op（fft_image_inv、phase_deg` など）が個別に担う。
• gallery2d_texture_freq family guide
• 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.
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.
fft_generic 0.40 0.50
▸ Load this pipeline · Load & run
• gallery2d_texture_freq — py -3.11 examples/gallery2d_texture_freq.py
image as input)identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter
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).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.