1. An object detection method comprising: for each of a set of patches, encoding features of each of the patch with a non-linear mapping function; computing patch statistics on the encoded features for approximating a window-level non-linear operation with a set of patch-level operations; extracting windows from the image, each window comprising a sub-set of the set of patches; scoring each of the windows based on the computed patch statistics of the respective sub-set of patches; and providing for detecting objects in the image based on the window scores, wherein at least one of the encoding patch features, computing patch statistics, extracting windows, scoring the windows, and detection of objects is performed with a processor.