vol_affine — 3D `geom_transform` op

• Data kinds: voxel → voxel

• Call: import fullseye as fs; fs.ledger.vol_affine(vol, matrix, offset=(0, 0, 0), order=1, output_shape=None, mode='constant', cval=0.0) (to call the implementation directly, import volxform; volxform.vol_affine(vol, matrix, offset=(0, 0, 0), order=1, output_shape=None, mode='constant', cval=0.0); from the registry, ops3d.get("vol_affine"))

Usage

General affine resampling (`scipy.ndimage.affine_transform`).

Convention (pinned — read this before writing a matrix): this is

scipy's pull (output -> input) resampler. For every output voxel at

integer coordinate `o = (z, y, x)` the result is the input interpolated

at `matrix @ o + offset`::

out[o] = vol[ matrix @ o + offset ] # (z, y, x) order, voxels

Consequences: `matrix = 2*I` makes the object appear half size (each

output step strides two input voxels); `offset = (1, 2, 3)` moves the

object by `(-1, -2, -3)`. To *push* content through a forward transform

`T (the pose from a registration), pass the **inverse** of T`. The

test suite machine-pins this direction.

*matrix* is either a `(3, 3)` linear part (with *offset* a separate

length-3 translation) or a `(4, 4)` homogeneous matrix

`[[A, t], [0, 0, 0, 1]] — then A / t` are taken from the matrix,

the bottom row must be exactly `(0, 0, 0, 1)`, and *offset* must stay at

its zero default (a second translation would be ambiguous). Any other

shape raises `ValueError`.

*output_shape* defaults to the input shape; an explicit one is cap-checked

against `MAX_VOXELS` before allocation. *order* is the spline degree

(exact integer 0..5). Voxels whose source coordinate falls outside the

input are filled per *mode*/*cval*.

Returns a float64 volume of *output_shape*.

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.

Runnable examples (verified samples that actually call this op)

• vol_geometry_transform — py -3.11 examples_3d/vol_geometry_transform.py

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

voxel_to_mips · voxel_to_mesh · signed_distance_field · to_points · sobel3d · hessian3d · curvature_maps · edt_jfa

Same category (`geom_transform`)

vol_resize · vol_rotate

*Provenance: volxform.py — 3D operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

vol_affine — 3D geom_transform op