1. A method of processing an image of a driver's license captured by a mobile device, comprising: receiving a first image of a document captured by a mobile device; cropping the first image around the document to produce a cropped image of the document, wherein cropping the first image includes using a rounded corner detection test; determining whether the document is a driver's license based on whether one or more rounded corners are identified when cropping the first image using the rounded corner detection test, wherein the rounded corner detection test comprises approximating connected points of edge pixels of the cropped image with a spline and estimating a curvature of the spline; and if the document is determined to be a driver's license, identifying a layout of the driver's license; binarizing the cropped image to produce a binarized image; and outputting the binarized image of the driver's license.