What it is

A technical demonstration that real medical-image registration software can run entirely inside a modern browser, with per-frame interactivity, on images supplied by the user, without sending those images anywhere.

The registration pipeline is Elastix — a long-standing, peer-reviewed component of the Insight Toolkit — compiled to WebAssembly through the ITK-Wasm project. The default parameter map ("B-spline") performs a multi- resolution non-rigid registration with several hundred iterations of adaptive stochastic gradient descent. The deformation field shown in the playground is computed by applying the registered transform to a pair of coordinate-ramp images and subtracting — a standard trick that works for any transform type Elastix produces.

What it isn't

Not a clinical product. Not a medical device. Not validated for diagnosis. The default parameters were chosen for visual clarity on small browser-friendly inputs, not for clinical accuracy. Do not use anything you see here for patient care.

Privacy posture

The page makes no network call after its initial load. The WebAssembly modules and any sample images you see are served from the same origin. There is no upload endpoint, no analytics script, no third-party SDK, no cookies. Open your browser's network panel during a registration run and you will see exactly zero requests beyond the first page load.

Stack & credits

• UI Astro 5 · React island for the playground
• REGISTRATION @itk-wasm/elastix · Apache-2.0
• RUNTIME itk-wasm · Apache-2.0
• TYPE Instrument Serif · IBM Plex Sans · IBM Plex Mono — self-hosted via @fontsource
• SAMPLE brain.png — BrainProtonDensitySlice from ITK · Apache-2.0