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 $\mu \text{W}$ , 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- $\mu \text{m}$ pixel vision sensor is manufactured in a 110-nm 1P4M CMOS and occupies 25.4 mm2.