1. A document authentication device comprising: an image capture interface that receives a captured image of at least a portion of an article, wherein the portion of the article includes an image having a first retroreflective feature and a second retroreflective feature; a masking image generator that generates a masking image from the captured image; a fast masked normalized cross-correlation (FMNCC) module that applies the masking image to the captured image to obtain a masked image and calculates a modified normalized cross-correlation between a reference image associated with the first retroreflective feature and the masked image; and a display that outputs indicia of one or more matches between the reference image and the captured image.