This app is based on a tutorial on using Swift and AVFoundation for extracting and displaying frames of the camera in real-time.
The tutorial was written for Swift 3, but this repo is using Swift 4.0
This project uses CocoaPods to pull in the dependency to OpenCV. A good resource for using cocoapods for opencv, and connecting the C++ library through Objective-C++ into Swift can be found here.
For a tutorial that does this without using CocoaPods, see here
I followed this tutorial which shows how to convert from a UIImage to a cv::Mat. In addition, I had to add the implementation for the UIImageToMat and MatToUIImage functions myself due to linker (ld) errors, as described in this SO post. It's kind of seems strange that the ios_conversions.mm has to be manually added, but it does make sense as it requires Foundation headers and an Objective-C++ compiler. It could be better documented however... I wonder if I hadn't used CocoaPods if that source file would have been copied/compiled automatically for me.