Title
Sound event detection with binary neural networks on tightly power-constrained IoT devices
Abstract
Sound event detection (SED) is a hot topic in consumer and smart city applications. Existing approaches based on deep neural networks (DNNs) are very effective, but highly demanding in terms of memory, power, and throughput when targeting ultra-low power always-on devices. Latency, availability, cost, and privacy requirements are pushing recent IoT systems to process the data on the node, close to the sensor, with a very limited energy supply, and tight constraints on the memory size and processing capabilities precluding to run state-of-the-art DNNs. In this paper, we explore the combination of extreme quantization to a small-footprint binary neural network (BNN) with the highly energy-efficient, RISC-V-based (8+1)-core GAP8 microcontroller. Starting from an existing CNN for SED whose footprint (815 kB) exceeds the 512 kB of memory available on our platform, we retrain the network using binary filters and activations to match these memory constraints. (Fully) binary neural networks come with a natural drop in accuracy of 12-18% on the challenging ImageNet object recognition challenge compared to their equivalent full-precision baselines. This BNN reaches a 77.9% accuracy, just 7% lower than the full-precision version, with 58 kB (7.2× less) for the weights and 262 kB (2.4× less) memory in total. With our BNN implementation, we reach a peak throughput of 4.6 GMAC/s and 1.5 GMAC/s over the full network, including preprocessing with Mel bins, which corresponds to an efficiency of 67.1 GMAC/s/W and 31.3 GMAC/s/W, respectively. Compared to the performance of an ARM Cortex-M4 implementation, our system has a 10.3× faster execution time and a 51.1× higher energy-efficiency.
Year
DOI
Venue
2020
10.1145/3370748.3406588
ISLPED '20: ACM/IEEE International Symposium on Low Power Electronics and Design Boston Massachusetts August, 2020
DocType
ISBN
Citations 
Conference
978-1-4503-7053-0
2
PageRank 
References 
Authors
0.37
7
6
Name
Order
Citations
PageRank
Gianmarco Cerutti181.88
Renzo Andri2876.44
Cavigelli, L.324422.75
Elisabetta Farella443350.45
Michele Magno550059.74
Luca Benini6131161188.49