tm_backproject_unfiltered — 2D tomography op

• Data kinds: image → image

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

Usage

Plain (UN-filtered) back-projection of the input sinogram -- the classic blurry reconstruction. No ramp filter is applied, so high frequencies are suppressed and every point spreads a 1/r blur: this deliberately shows why FBP's filter is needed. `a/b are unused (this is the fixed naive baseline). Uses skimage.transform.iradon with filter_name=None` when available, else the NumPy plain back-projection. Output refit to HxW.

Detailed usage guide

• gallery2d_physics_alife_3d 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_physics_alife_3d — py -3.11 examples/gallery2d_physics_alife_3d.py

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

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

Same category (tomography)

tm_radon_forward · tm_fbp_reconstruct · tm_sart_reconstruct · tm_sinogram_denoise

*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.