hx_estimate_sl_al_zc — 2D `halcon_ext` op

• Data kinds: image → feature

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

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

hx_estimate_sl_al_zc: 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.*

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

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

Usage

Zheng-Chellappa: estimate the slant, corrected by the gradient energy.

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

`hx_estimate_sl_al_lr と同じ arccos(<I>) の slant に、Sobel 勾配振幅の平均 e`(1 で頭打ち)による係数

`(1 + min(e, 1)) を掛けて、pi/2 で割り 1 で頭打ちした np.float64` を返す。「勾配が強い=斜光=slant 大」

という向きの補正。

• `a, b` は未使用。

補正係数は 1〜2 倍で、平均輝度が低く勾配も強い画像では上限 1 に張り付く。勾配振幅はテクスチャや雑音でも

増えるので、照明以外の要因で slant が過大に出る。前段に `gauss_filter` を置くと雑音分の勾配は減る。

反射率の推定は `hx_estimate_al_am、方位は hx_estimate_tilt_zc`。

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.

hx_estimate_sl_al_zc 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 `feature` as input)

identity · feature_to_img

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_estimate_sl_al_zc — 2D halcon_ext op