aug_vignette — 2D `augmentation` op

• Data kinds: image → image

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

Usage

Radial lens vignetting following the natural cos^4 falloff law. With `r the normalised distance from the image centre and R = 0.35 + 1.15*b the falloff radius, the transmission is cos(atan(r/R))^4 = 1/(1 + (r/R)^2)^2 -- the textbook cos^4 law. a blends it in: out = v * (1 - a + a*falloff)`, so a=0 is a no-op and a=1 is full vignetting. Centre stays brightest; strictly darkening, never amplifying.

Detailed usage guide

• gallery2d_color_artistic 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.

Runnable examples (verified samples that actually call this op)

• gallery2d_color_artistic — py -3.11 examples/gallery2d_color_artistic.py

• sim2real_and_alife — py -3.11 examples/sim2real_and_alife.py

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

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

Same category (`augmentation`)

aug_shot_noise · aug_read_noise · aug_fixed_pattern · aug_motion_blur · aug_chromatic · aug_rolling_shutter · aug_jpeg_blocks · aug_cutout

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

aug_vignette — 2D augmentation op