1. A method of determining functionality of a vision-based imaging system for a vehicle, the method comprising the steps of: capturing images by the vision-based imaging system, the images including landmarks that are identified in multiple images for distinguishing displacement of landmarks between the images; a processing module generating an edge map for each of the images; comparing like regions of at least two edge maps for distinguishing displacement of a landmark between the at least two edge maps, each edge map being constructed of pixels having varying intensity values, wherein each pixel location of a first edge map is compared with a same pixel location of a second edge map, wherein each of the same pixel locations of the at least two edge maps are compared within one another for determining whether each compared pixel location has a different intensity value; and determining an aggregate number of pixel locations having a different intensity value between the at least two edge maps; determining whether the aggregate number is greater than a threshold for indicating displacement of the landmarks between the at least two edge maps; and generating an error message in response to the aggregate number being less than the threshold.