hx_add_noise_contour — 2D `halcon_ext` op

• Data kinds: contour → contour

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

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

hx_add_noise_contour: 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):

▸ hx_add_noise_contour: knob a sweep (docs site)

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

Stages (the ops that come before → this op, left to right):

▸ hx_add_noise_contour: stages (docs site)

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

▸ hx_add_noise_contour: other inputs (docs site)

Usage

Add white Gaussian noise to the contour points (std from a; deterministic with a fixed seed).

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

各 contour の全点座標 (row, col) に、平均 0・標準偏差 `std` のガウス雑音を独立に加えて返す。乱数は

`np.random.default_rng(12345)` を呼ぶたびに作り直すので、同じ入力なら常に同じ雑音が出る(決定的)。

• `a → 標準偏差 std = a*3`(0〜3 画素。a=0 なら無変化)。

• `b` は未使用。

雑音列は contour の順番と点数に依存するため、前段で点の順序や本数が変わると同じ `a` でも雑音の当たり方が

変わる。ロバスト性の検証(`hx_fit_circle_contour の残差がどれだけ増えるか等)や、smooth_contours_xld` の

効果確認に使う。

Detailed usage guide

• gallery2d_halcon_ext 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.

threshold 0.50 0.50
sk_find_contours 0.50 0.50
hx_add_noise_contour 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_halcon_ext — py -3.11 examples/gallery2d_halcon_ext.py

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

identity · select_contours · smooth_contours · fit_line_contours · contours_to_region · count_contours · total_length · select_contours_xld

Same category (`halcon_ext`)

hx_gen_circle · hx_gen_ellipse · hx_gen_rectangle2 · hx_gen_checker_region · hx_gen_grid_region · hx_gabor · hx_fit_surface1 · hx_fit_surface2

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

hx_add_noise_contour — 2D halcon_ext op