sk_adjust_log — 2D `gray` op

• Data kinds: image → image

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

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

sk_adjust_log: 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

Logarithmic tone transform (log transform). A tonal correction that lifts dark areas using a logarithmic curve of the form `out = gain * log(1 + in)` -- similar in use to gamma correction, but with a nonlinear curve that lifts only the darkest areas more strongly.

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

HALCON の log_image(Calculate the logarithm of an image.)に相当。実装は `exposure.adjust_log(clip(v,0,1), gain=0.5+1.5*a) の結果を [0,1] へ clip したもの —— a は gain を 0.5〜2.0 に振る。b は未使用。gain が 1 を超えると出力が 1 を僅かに超えることが実測されている(a=0.5 で max=1.1380)ため、image 契約([0,1])を守るために出口で明示的に clip している —— パイプライン内では ops._apply` の段間 clip と同じ値になるためビット不変だが、直接呼び出した時の白飛びの見え方は clip 追加前と変わる。

Detailed usage guide

• gallery2d_gray_arith 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.

sk_adjust_log 0.50 0.50

▸ Load this pipeline · Load & run

Runnable examples (verified samples that actually call this op)

• gallery2d_gray_arith — py -3.11 examples/gallery2d_gray_arith.py

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

identity · gaussian · mean_box · bilateral · unsharp · median · min_filter · max_filter

Same category (`gray`)

gamma · invert · scale_clip · equalize · sigmoid · clahe · sk_adapthist · sk_enhance_contrast

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

sk_adjust_log — 2D gray op