Realtime plane-wave software beamforming with an iPhone

This work describes the implementation of software plane-wave beamforming performed on the GPU of an Apple iPhone 6s and 6s Plus. The code can run on any current iOS device that supports the Metal API. The implementation is largely written in Swift, with some Objective-C, while the core processing component was written in Metal, Apple's new GPU programming language which provides low-overhead compute shaders for exploiting the device's GPU. We have demonstrated that ultrasound channel data recorded on a Verasonics Vantage system can be wirelessly transmitted to the iPhone using a simple networking implementation obtaining a frame rate up to 5 FPS including serialization and transmission, and easily 60+ FPS for on device processing depending on number of samples and output image size.