ISO 20462-3:2005 specifies the quality ruler method for estimating image quality through calibrated psychophysical experiments. It defines the nature of quality rulers, hardcopy and softcopy implementations, methods for generating reference stimuli, experimental conditions, and use of the standard quality scale (SQS). The standard supports image-quality evaluation for capture and display devices, image-processing algorithms, and other imaging-system variables, with results expressed in just noticeable differences (JNDs) or SQS units.
It includes requirements and guidance for quality ruler experiments, physical apparatus, reference stimuli, modulation transfer function-based stimulus generation, SQS determinations, calibration, sample observer instructions, and a binary search routine for softcopy evaluations.
Application Scope: Photography research, image-quality measurement, camera and display evaluation, image-processing assessment, psychophysical testing, and imaging-system performance comparison.
