1. A method performed by a processor for detecting presence of a vehicle in one or more images, comprising: determining a region of interest (ROI) in the one or more images, without a priori knowledge of whether the vehicle is present in the ROI; computing a plurality of sets of image descriptors, each one of the sets of image descriptors corresponding to a location within the ROI; classifying each of the sets of descriptors, using a multi-class classifier comprising a structure of related classifiers for a set of associated vehicle parts, to obtain a likelihood value of whether a vehicle part is present at the location corresponding to the set of descriptors being classified; determining whether the vehicle is likely present within the ROI based on a comparison between a function of the obtained likelihood values and a predetermined threshold value.