img_to_monogenic — 2D `bridge` op

• Data kinds: image → qimage

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

img_to_monogenic: 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):

▸ img_to_monogenic: knob a sweep (docs site)

Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):

▸ img_to_monogenic: knob b sweep (docs site)

On other images (synthetic scene / photo / coins. Top row: inputs, bottom row: their outputs. Knobs at default):

▸ img_to_monogenic: other inputs (docs site)

*The 4th column is a colour (H,W,3) input. This op handles colour without crossing channels (it does not convolve the colour channel as a third spatial axis).*

Usage

Build the single-scale monogenic signal of the image (a quaternion field (H,W,4), sort `qimage`).

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

台帳の `monogenic_signal`(Felsberg & Sommer 2001)そのもの: 対数放射状の

raised-cosine 帯域通過を掛け、その Riesz 対と組にして四元数

`(帯域通過像, R1, R2, 0) に詰める。tb_monogenic_amplitude` /

`tb_monogenic_phase / tb_monogenic_orientation` は **この形の qimage

だけ** を受け付ける(色の四元数 `tb_rgb_to_quaternion` を渡すと

「モノジェニック信号ではない」と拒否する)ので、その族の入口はこちら。

• `a → 中心波長 wavelength_px = 8 * (0.25 + 1.75 * a)` 画素

(a=0.5 で 9 px。小さいほど細かい構造に応答)。

• `b → 帯域幅 bandwidth_octaves = 1.0 * (0.25 + 1.75 * b)` オクターブ

(b=0.5 で 1.125)。

• 返り値: `(H, W, 4)` float64。値域は入力に依存し [0,1] に収まらない

(Riesz 対は符号つき)。

Detailed usage guide

• gallery2d_bridge 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.

img_to_monogenic 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_bridge — py -3.11 examples/gallery2d_bridge.py

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

identity · tb_quaternion_to_rgb · tb_quat_norm · tb_quat_conjugate_image · tb_quat_normalize_image · tb_monogenic_amplitude · tb_monogenic_phase · tb_monogenic_orientation

Same category (`bridge`)

img_to_points · img_to_keypoints · img_to_signal · img_to_projection_profile · img_to_counts · img_to_matrix · img_to_video · img_to_volume

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

img_to_monogenic — 2D bridge op