1. A method for detecting traffic lights, comprising: obtaining a color image captured by a camera; converting the color image into a first monochrome scale image; converting the first monochrome scale image into a first binary image; identifying a first set of candidate blobs in the first binary image based on at least one predetermined geometric parameter; and determining whether a first region in the color image, which first region corresponds to one of the first set of candidate blobs, represents a green traffic light using a green traffic light classifier.