A method of detecting a feature of a vehicle in an image of a vehicle
includes providing a digitized image of a vehicle, providing a first
filter mask over a first subdomain of the image, where the filter mask is
placed to detect a feature in the image, calculating a function of a
gradient of the image inside the first masked subdomain, and detecting
the presence or absence of a vehicle feature within the first masked
subdomain based on the value of the gradient function.