SplineOps#

Projection-based antialiased resizing for N-D scientific arrays.

SplineOps is designed for precise, repeatable downsampling of regular-grid 2-D images and 3-D volumes. It combines explicit coordinate semantics, a readable Python reference implementation, a native CPU backend, and reusable plans for fixed-geometry workloads.

Start here#

import numpy as np
from splineops import resize

volume = np.random.default_rng(0).random((64, 192, 192), dtype=np.float32)
coarse = resize(
    volume,
    output_size=(32, 96, 96),
    method="cubic-antialiasing",
)

The antialiasing methods project the input spline onto a coarser spline space instead of treating downsampling as interpolation alone. Continue with the Five-minute quickstart, then use the Volume downsampling tutorial for a batched 3-D workflow.

Choose SplineOps when#

  • continuous-valued 2-D or 3-D NumPy data must be downsampled;

  • coordinate, boundary, and output-shape semantics must be explicit;

  • aliasing matters; or

  • many arrays share one resize geometry.

Choose another tool when differentiable GPU execution or automatic physical-space image metadata is required. For ordinary display-image scaling, OpenCV or Pillow may be simpler. Categorical labels normally require nearest-neighbour rather than spline-projection semantics.

Release status#

SplineOps 2.1 public maturity#

Module

Status

Public position

Resize and ResizePlan

Stable

Native N-D interpolation and projection antialiasing with a Python reference path.

TensorSpline

Stabilizing

Continuous tensor-product models evaluated at arbitrary coordinates.

Other spline modules

Experimental

Available for research while their contracts and independent reference coverage mature.

SplineOps does not claim to be the fastest generic 2-D resizer. Its strongest position is explicit spline semantics, N-D projection antialiasing, native/reference parity, and reusable fixed-geometry execution. See Performance evidence for measured wins, losses, and limitations.

Research lineage#

SplineOps modernizes spline methods developed across the Biomedical Imaging Group at EPFL and its collaborators. Method citations, implementation history, and source provenance are recorded in Method and source provenance.

Getting started

Core guides

Evidence

Research modules

Project

Reference