An embodiment of a computer-implemented method generates a filtered set of region proposals for a digital image processing network. The method comprises generating a keypoint count map for a digital image, wherein the keypoint count map indicates how many keypoints have been detected near different pixels in the digital image. The method also comprises generating a keypoint integral image, wherein the keypoint integral image comprises a summed area table that is based on the keypoint count map. The method also comprises generating object existence indicators for an initial region set for the digital image based on the keypoint integral image, and extracting a keypoint-filtered region set from the initial region set based on the object existence indicators. The method may also comprise using the keypoint-filtered region set as region proposal input for an object proposal subsystem. Other embodiments are described and claimed.