An object detecting system includes an imaging device disposed on a vehicle and a controller that receives a two-dimensional image, which represents a scene ahead of the vehicle, from the imaging device. The controller includes a feature extraction unit, a motion-information calculator, a coordinate transformation unit, and an object-attribute determination unit. The feature extraction unit reads the image and extracts the edges of a feature in the image. The motion-information calculator evaluates the feature in the image and outputs feature velocity information for each image pixel that shows the edges of the feature. The coordinate transformation unit reads two-dimensional position coordinates of the image pixels and outputs transformed three-dimensional position coordinates. And the object-attribute determination unit determines, based on the transformed three-dimensional position coordinates and on the feature velocity information, whether the feature is a moving object.