1. A method for processing images, comprising: receiving, at a shelf edge detection component having a processor, an image containing shelf edge content; determining, by the processor, locations of instances of the shelf edge content by identifying interest point matches between the image and a reference image; determining, by the processor, regions in the image corresponding to shelf edges by: identifying a geometric pattern in the image based on the interest point matches; and forming clusters of instances of the geometric pattern; and estimating, by the processor, a number of shelf edges in the image based on the clusters.