Document reader having an optical filter with variable light transmission

A document reader system configured to capture an image of a document, the document reader system comprising:

• a document reader having:
• a transparent scan area configured to receive the document on a first side of the transparent scan area;
• a light source, positioned on a second side of the transparent scan area opposite the first side, configured to emit light towards the transparent scan area;
• an optical filter, positioned separate from the transparent scan area and between the light source and the transparent scan area, wherein the optical filter is a graduated neutral density (GND) filter and has a variable light transmission configured to modify light intensity of the light emitted by the light source, the variable light transmission of the GND filter corresponds to a filter pattern that is configured to correspond to a beam pattern of the light source;
• and
• an image sensor positioned on the second side of the transparent scan area and configured to capture the image of the document on the first side of the transparent scan area.