This part of ISO 20462 specifies:
a) the nature of a quality ruler;
b) hardcopy and softcopy implementations of quality rulers;
c) how quality rulers may be generated or obtained; and
d) the standard quality scale (SQS), a fixed numerical scale that may be measured using quality rulers.
ISO 20462-3:2005 Referenced Document
ISO 3664 Graphic technology and photography - Viewing conditions*, 2009-04-01 Update
ISO 20462-3:2005 history
2012ISO 20462-3:2012 Photography - Psychophysical experimental methods for estimating image quality - Part 3: Quality ruler method
2005ISO 20462-3:2005 Photography - Psychophysical experimental methods for estimating image quality - Part 3: Quality ruler method