Text quality of image output from copiers or printers is very important in the office environment. Visual examination has previously been used as a basis for determining the legibility of printed characters. We concentrate on line reproduction quality and modulation transfer function (MTF), and study the correlation between legibility and each of them in order to develop an objective evaluation method. As a result, we have found that we can predict legibility by better understanding and use of these two characteristics.
Tetsuya Itoh, Soh Hirota, "Evaluation of Electrophotographic Legibility using Line Reproduction Quality and MTF" in Journal of Imaging Science and Technology, 1999, pp 478 - 483, https://doi.org/10.2352/J.ImagingSci.Technol.1999.43.5.art00013