Dadu-Eye: A 5.3 TOPS/W, 30 fps/1080p High Accuracy Stereo Vision Accelerator

Abstract

Stereo vision is widely deployed on robots and drones to enable depth estimation at a low cost. The combination of lightweight deep neural network (DNN) and cost volumes algorithm is proved to possess the advantages of both high depth estimation accuracy and speed. However, currently there is no accelerator architecture compatible with both efficient DNN inference and cost generation algorithms such as stereo matching. This work proposes a stereo vision accelerator called Dadu-eye, dedicated to real-time processing of high-resolution image streams. The proposed architecture adopts a pipelined hardware design with the techniques of operation approximation and scheduling-level optimization. First, a cost estimation block is designed to generate cost volumes from both luminance and color information. Second, a super pipelined multiplication and accumulation array with a row scan-based fused-layer convolution scheduling is proposed to perform the encoding and decoding neural network efficiently. Finally, an optical flow block is designed and cooperates with the array to approximately predict half of the frames’ depth to achieve real-time (30fps) processing on 1080p view. Based on the SMIC 40 nm CMOS process, this stereo vision accelerator achieves 5.3 TOPS/W power efficiency and significantly reduces 81% off-chip memory access.