1. A method for detecting a road region, comprising: obtaining, via a storage device, a color image; selecting a candidate road region within the color image according to a road model; identifying a seed pixel from the candidate road region; determining, via a processing device, a brightness threshold and a color threshold according to brightness distances and color distances from pixels in the candidate road region to the seed pixel; and determining that the pixels in the candidate road region belong to the road region based on the brightness threshold and the color threshold.