Image Gradient Evolution: A Visual Cue for Danger

摘要

This paper is concerned with the task of visual motion-based navigation. Acritical requirement of the task is the ability to estimate 3-D depth and motion from visual information. We present a new concept called image gradient evolution (IGE), which utilizes the change of image spatial gradients over time as a threat cue; an approaching object induces 2-D expanding motion and causes the image spatial structure to stretch so the image gradients decrease. Based on this idea, our method offers a one-step solution directly from image gradients, instead of from optical flow and its derived properties.