Historical
ISO 20462-3:2005
Photography - Psychophysical experimental methods for estimating image quality - Part 3: Quality ruler method
ISO 20462-3:2005 specifies: the nature of a quality ruler; hardcopy and softcopy implementations of quality rulers; how quality rulers may be generated or obtained; and the standard quality scale (SQS), a fixed numerical scale that may be measured using quality rulers.
International Organization for Standardization [iso]