xsp_dct — 2D `frequency` op

• Data kinds: image → image

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

xsp_dct: 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

Displays the power spectrum of the 2D discrete cosine transform (DCT-II, ortho normalization) with logarithmic compression.

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

`scipy.fft.dctn で周波数領域に変換し、log1p(|係数|)` を [0,1] に

正規化する。`a, b` は未使用。低周波成分（出力の左上）ほど値が

大きく、DFT のパワースペクトルに近いが実数のみを扱う DCT なので対称な

折り返しは出ない。周波数成分の可視化・診断用。

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.

xsp_dct 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).*

xsp_dct — 2D frequency op