projective_trans_image_size — 2D geometry op

Data kinds: imageimage

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

HALCON equivalent: projective_trans_image_size (the HALCON reference is a useful guide to its meaning and parameters)

projective_trans_image_size: 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):

projective_trans_image_size: knob a sweep (docs site)

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

projective_trans_image_size: knob b sweep (docs site)

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

projective_trans_image_size: 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

The implementation is identical to `projective_trans_image (kind: "projective"). The name implies the output size can be specified, but this backend does not change the output canvas size and returns exactly the same trapezoidal distortion as projective_trans_image (a limitation of the approximation — the size-change feature is not reproduced). A stand-in for HALCON's projective_trans_image_size` (Apply a projective transformation to an image and specify the output image size.).

> The detailed description below is the original text — the summary and the headings are translated.

`a が歪みの強さ、b` が非対称さを振る。両方が使われる。

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.

projective_trans_image_size 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 (geometry)

rotate_img · deskew · rescale_img · affine_warp · sk_swirl · mirror_image · transpose_region · rotate_image


*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.