Image Quality Assessment of Ink-Jet Printers

The ink jet printer is a binary machine, which can either put a dot at a particular location on a sheet of paper, or leave it blank. It is the binary nature of the printer which prevents the direct use of the classical Modulation Transfer Function (MTF) which is used with great success in the study of optical systems. A Reflectance Transfer Function (RTF) can be used to assess the print quality of a binary printer. The RTF is obtained by reflectance measurements of a test target, which consists of a checkerboard of various frequencies. This is then cascaded with the MTF of the human eye to give a Subjective Quality Factor (SQF). This SQF has been shown to correlate well with the subjective assessment of print quality by a panel of observers. Thus, the objective measurement of R F may be used to assess the print quality of the printer.