deform_tps — 2D deformation op

Data kinds: imageimage

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

deform_tps: 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.*

Sweeping knob a (0.1 / 0.5 / 0.9, the other knob at its default):

deform_tps: knob a sweep (docs site)

Sweeping knob b (0.1 / 0.5 / 0.9, the other knob at its default):

deform_tps: knob b sweep (docs site)

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

deform_tps: other inputs (docs site)

*The 4th column is a colour (H,W,3) input. This op handles colour without crossing channels (it does not convolve the colour channel as a third spatial axis).*

Usage

Thin-plate-spline warp over a 5x5 control grid (Bookstein, TPAMI 1989).

The 3x3 interior control points are displaced by the deterministic smooth

field `d = amp * [sin(2 pi f gx), cos(2 pi f gy)]` (gy, gx = the control

point's normalised coordinates), the 16 border control points are pinned so

the frame stays anchored. The backward map is the TPS interpolant fitted

from the *displaced* control points back to the original ones -- the unique

minimum-bending-energy interpolant, i.e. the surface a thin metal plate

would take -- and it is evaluated at every destination pixel before bilinear

resampling. `a sets the amplitude amp = 0.15*a*min(H,W), b` the

spatial frequency `f = 0.5 + 1.5b. a = 0` leaves the control points

where they are, so the solved map is the identity (up to sub-pixel resampling error).

Detailed usage guide

gallery2d_geometry 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.

deform_tps 0.50 0.50

▸ Load this pipeline  ·  Load & run

Runnable examples (verified samples that actually call this op)

gallery2d_geometrypy -3.11 examples/gallery2d_geometry.py

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

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

Same category (deformation)

deform_ffd · deform_mls


*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.