1. An image processing system for a front-view image sensor, comprising: an image sensor arranged on a vehicle to pick up a front-view image in front of the vehicle; a region setting device configured to set a plurality of image processing regions to cover on the front-view image various portions one after another, wherein the portions have different positions in a direction remote from the vehicle and the region setting device is configured to reduce the plurality of image processing regions in area as a distance of the portions from the vehicle increase; a feature extracting device configured to extract a feature out of the portions of the front-view image covered by the plurality of image processing regions set by the region setting device; and a presence judging device configured to judge the presence of an obstacle based on the feature extracted by the feature extracting device.