Unity XR Display Pre-Distortion for Distortion Correction

Unity prototypes demonstrating image-space pre-distortion techniques used in XR display pipelines, focusing on:

Barrel / Pincushion Distortion
Chromatic aberration

The goal of this project is to show how virtual content can be pre-distorted in software so that, after optical distortion, the perceived image appears correct.

All parameters are synthetic and chosen to make the effects clearly visible.

This repository demonstrates the logic of pre-distortion and correction, both of which are simulated

Display pipeline: Rendered image → software pre-distortion → optical distortion → perceived image The goal of pre-distortion is to ensure that, after optical distortion, the perceived image appears geometrically and chromatically correct.

What this demo shows

Barrel and Pincushion distortions and their inverse pre-distortion correction
Chromatic aberration and its inverse pre-distortion correction
Unity-based implementation using shaders and simple runtime controls

Scenes

Scene 1: Barrel/Pincushion Distortion Pipeline
Barrel and pincushion distortion applied to a checkerboard pattern, with toggleable pre-distortion correction.
Scene 2: Chromatic Aberration Pipeline
Chromatic aberration applied to a Siemens sinusoidal star pattern, with toggleable pre-distortion correction.

Each scene allows visual comparison between:

original content
optics distortion only
pre-distortion only
pre-distortion + optics distortion (corrected result)

Distortion model for Barrel and Pincushion distortion

Brown’s simplified Forward radial transform:

$$r_{d}=f\left(r_{u}\right)=r_{u}+c_{1} r_{u}^{3}+c_{2} r_{u}^{5}$$

Brown’s simplified Inverse radial transform:

$$f^{-1}\left(r_{d}\right) \approx \frac{c_{1} r_{d}^{2}+c_{2} r_{d}^{4}+c_{1}^{2} r_{d}^{4}+c_{2}^{2} r_{d}^{8}+2 c_{1} c_{2} r_{d}^{6}}{1+4 c_{1} r_{d}^{2}+6 c_{2} r_{d}^{4}}$$

Images