An Automated Design Flow for Adaptive Neural Network Hardware Accelerators

Image and video processing are one of the main driving application fields for the latest technology advancement of computing platforms, especially considering the adoption of neural networks for classification purposes. With the advent of Cyber Physical Systems, the design of devices for efficiently executing such applications became more challenging, due to the increase of the requirements to be considered, of the functionalities to be supported, as well as to the demand for adaptivity and connectivity. Heterogeneous computing and design automation are then turning into essential. The former guarantees a variegated set of features under strict constraints (e.g., by adopting hardware acceleration), and the latter limits development time and cost (e.g., by exploiting model-based design). In this context, the literature is still lacking adequate tooling for the design and management of neural network hardware accelerators, which can be adaptable and customizable at runtime according to the user needs. In this work, a novel almost automated toolchain based on the Open Neural Network eXchange format is presented, allowing the user to shape adaptivity right on the network model and to deploy it on a runtime reconfigurable accelerator. As a proof of concept, a Convolutional Neural Network for human/animal classification is adopted to derive a Field Programmable Gate Array accelerator capable of trading execution time for power by changing the resources involved in the computation. The resulting accelerator, when necessary, can consume 30% less power on each layer, taking about overall 8% more time to classify an image.