1. A system for optical navigation comprising: an image sensor configured to capture frames of image data of a target surface; a spatial noise pattern estimation module configured to produce a spatial noise pattern estimate of a spatial noise pattern in the captured frames of image data caused by contamination on at least one component of the system using at least some of the captured frames of image data; a normalization module configured to normalize particular frames of image data using the spatial noise pattern estimate to substantially remove the spatial noise pattern from the particular frames of image data to produce normalized frames of image data; and a navigation engine configured to generate displacement values based on the normalized frames of image data.