1. A system comprising: a processor and a memory; and a module configured to cause the processor to: obtain a first image of a user interface element that includes text; responsive to obtaining the first image, generate a second different image that comprises a grayscale representation of the first image; correlate a subset of a plurality of maxima of a histogram of the second image with a background pixel in the second image; determine a first maximum on the histogram of the second image by locating at least one maximum from the correlated ones of the plurality of maxima; responsive to determining the first maximum on the histogram of the second image, identify, in the first image, a first pixel corresponding to the determined first maximum; select, from the uncorrelated ones of the plurality of maxima, a second maximum farthest from the first maximum; wherein the second maximum corresponds to the text of the user interface element and the first maximum does not correspond to the text of the user interface element; responsive to selecting the second maximum, identify, in the first image, a second different pixel corresponding to the determined second maximum; and calculate a ratio of a value associated with one of the identified first and second pixels to a value associated with the other of the identified first and second pixels.