A Low-Power VGA Vision Sensor with Embedded Event Detection for Outdoor Edge Applications

We report on a low-power VGA vision sensor embedding event-detection capabilities targeted to battery-powered vision processing at the edge. The sensor relies on an always-on double-threshold dynamic background subtraction (DT-DBS) algorithm. The resulting motion bitmap is de-noised, projected along xy-axes of the array of pixels and filtered to robustly detect moving targets even in noisy outdoor scenarios. The chip operates in motion detection (MD), applied on a QQVGA sub-sampled image, looking for anomalous motion in the scene at 344 μW, and in imaging mode (IM), delivering full-resolution gray-scale images with associated local binary pattern (LBP) coding and motion bitmaps at 8 frames/s and 1.35 mW. The 4-μm pixel vision sensor is manufactured in a 110-nm 1P4M CMOS and occupies 25.4 mm².