1. A method, comprising: dividing, using a processor, a tetragon comprising a digital representation of a document in a digital image into a plurality of sections, each section comprising a plurality of pixels; for each section: determining whether the section contains one or more sharp pixel-to-pixel transitions in a first direction; counting a total number of first direction sharp pixel-to-pixel transitions for the section (S S1 ); determining whether the section contains one or more blurred pixel-to-pixel transitions in the first direction; counting a total number of first-direction blurred pixel-to-pixel transitions for the section (S B1 ); determining whether the section contains one or more sharp pixel-to-pixel transitions in a second direction; counting a total number of second-direction sharp pixel-to-pixel transitions for the section (S S2 ); determining whether the section contains one or more blurred pixel-to-pixel transitions in the second direction; counting a total number of second-direction blurred pixel-to-pixel transitions for the section (S B2 ); determining the section is blank upon determining: S S1 is less than a predetermined sharp transition threshold, S B1 is less than a predetermined blurred transition threshold, S S2 is less than a predetermined sharp transition threshold, and S B2 is less than a predetermined blurred transition threshold; and determining, for all non-blank sections, a first direction blur ratio r 1 =S S1 /S B1 ; determining, for all non-blank sections, a second direction blur ratio r 2 =S S2 /S B2 ; determining that a non-blank section is blurred in the first direction upon determining that r 1 is less than a predefined section blur ratio threshold; and determining that a non-blank section is blurred in the second direction upon determining that r 2 is less than the predefined section blur ratio threshold; and determining that a non-blank section is bluffed upon determining one or more of: the section is blurred in the first direction, and the section is blurred in the section direction; and determining a total number of blurred sections; calculating an image blur ratio R comprising: the total number blurred sections to a total number of sections; and determining the digital image is blurred upon determining the image blur ratio is greater than a predetermined image blur threshold.