Download OpenCV for Unity FREE Unity. 

Works with Unity Cloud Build

iOS & Android support
Windows10 UWP support
Lumin ( MagicLeap ) support
WebGL support
Win & Mac & Linux Standalone support
Preview support in the Editor

It is an Assets Plugin for using OpenCV 4.3.0 from within Unity.

Official Site | ExampleCode | Android Demo WebGL Demo | Tutorial & Demo Video | Forum | API Reference | Support Modules | Free Trial Version

Features:
– Since this package is a clone of OpenCV Java, you are able to use the same API as OpenCV Java 4.3.0 (link).