tb_lf_synthetic_aperture — 2D typed op

Data kinds: lightfieldimage

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

tb_lf_synthetic_aperture: 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).*

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

tb_lf_synthetic_aperture: stages (docs site)

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

tb_lf_synthetic_aperture: other inputs (docs site)

Usage

Refocus through a shaped aperture — and, with `reduce="median"`, through occluders.

Same shift-and-add geometry as :func:lf_refocus, with two additions:

• *mask* — a `(V, U) weight array from :func:lf_aperture_mask` (or your

own). A small mask is a stopped-down aperture: less defocus blur, less

light. `None` weights every view equally.

• *reduce* — how the aligned views are combined. `mean` is the classical

(and linear) synthetic aperture. `median` is the interesting one: when

a foreground occluder covers a *minority* of the views at a pixel, the

median rejects it and the background behind it is reconstructed —

looking through a fence, or through a rack of parts. `max / min`

are the order-statistic extremes, useful for specular / shadow work.

`median, max and min` use the mask only to *select* views

(weight > 0), because an order statistic has no meaningful weighting;

that is stated here rather than silently ignoring the weights.

The see-through result is not a metaphor. When fewer than half the views

are blocked at a hidden pixel, more than half of them carry the identical

background sample and the median is that sample exactly. Measured

2026-09-01 on a 9x9x64x64 field with an occluder covering 25% of the centre

view at slope 3.0 (blocking at most 46% of the views at any hidden pixel):

RMS against the true, hidden background was 0.0 for `median` and

0.159 for `mean`, with the centre view itself at 0.280. Push the coverage

to 35% (up to 60% of views blocked) and the guarantee is gone — the median

lands at 0.133, worse than nothing.

Returns a `(H, W)` 2-D image.

Raises `ValueError`: *lf* not a valid light field, a *mask* whose

shape is not `(V, U)` or which is non-finite / negative / selects no view,

a non-finite or over-large *slope*, unknown *reduce* / *interp* / *edge*.

Typed bridge of the lightfield op `lf_synthetic_aperture into the 2-D evolution registry: the same implementation, called under the op(v, a, b) convention. This op has no tunable parameter; a and b` are unused.

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.

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_lightfield 0.50 0.50
tb_lf_synthetic_aperture 0.50 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

The examples below call the underlying ledger op lf_synthetic_aperture. This bridge op is the same implementation adapted to the fn(v, a, b) convention, so the behaviour carries over unchanged (only the call form differs).

lightfield_depthpy -3.11 examples/lightfield_depth.py

poc_compound_eyepy -3.11 examples/poc_compound_eye.py

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

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

Same category (typed)

tb_points_to_voxel · tb_estimate_point_normals · tb_iss_keypoints · tb_project_points · tb_render_point_depth · tb_statistical_outlier_removal · tb_radius_outlier_removal · tb_voxel_grid_downsample


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

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.