A Low-Latency FPGA Accelerator for YOLOv3-Tiny With Flexible Layerwise Mapping and Dataflow

Object detection models have demonstrated outstanding performance in terms of accuracy. However, mapping convolutional neural network-based object-detection models to memory and computing-constrained devices is still challenging, which commonly leads to accuracy degradation and long latency. To address the problem, this work presents a design methodology to map the YOLOv3-tiny model onto a small FPGA board, in this case the Nexys A7-100T, which only has 0.5 MB on-chip SRAM and 240 DSPs. First, we design four identical MAC arrays to maximize the throughput by utilizing both DSPs and LUTs. Second, to exploit the MACs fully, we propose a dynamic data reuse scheme that handles inter-layer and intra-layer executions effectively under a small on-chip SRAM footprint. To this end, the proposed accelerator achieves an inference speed of 76.75 frames per second and throughput of 95.08 GOPs at 100MHz and consumes power of 2.203W. Specifically, it achieves a hardware utilization rate of 82.53%, thus significantly outperforming current YOLOv3-tiny accelerators.