1. A method for detecting a seat belt violation in a vehicle, comprising: receiving an image of a front side of a vehicle; detecting a windshield of the vehicle in the image; cropping the windshield out of the image and discarding a remainder of the image; locating a passenger through the windshield; identifying a region of interest through the windshield that includes a portion of the passenger where a seat belt is visible if the seat belt is buckled, wherein the region of interest is defined relative to a plurality of landmark points that are at set positions with respect to the windshield of the vehicle, wherein a first of the landmark points is on a rear view mirror of the vehicle, wherein a second of the landmark points is at a bottom center of the windshield, and wherein a third of the landmark points is on a dashboard of the vehicle in front of a steering wheel; extracting one or more first features from the region of interest of the image; comparing the one or more first features to one or more second features extracted from a plurality of sample images, wherein the one or more second features are used to train a classifier; and determining, using the classifier, whether the seat belt is buckled in the image based upon the comparison.