Determining the lowest light level at which a camera still delivers acceptable image quality requires well‑defined tolerance thresholds for all relevant factors. This paper presents a psychophysical study comparing expert and non‑expert evaluations across photographic and security‑camera use cases to establish application‑specific acceptance limits. The results provide a foundation for understanding how image quality degrades as light decreases and where compensation mechanisms reach their limits.
In order to determine the lowest light level at which a digital camera can still deliver acceptable images, acceptance thresholds must be established for all related image quality factors. ISO 19093[1] describes these factors and how they can be measured. However, the acceptance thresholds may depend on the application for whichthe images were captured, as well as on people's individual tolerance for degradation in the different image quality factors. To generate a standard set of tolerance levels for photographic applications, a psychophysical experiment was performed, as described in this paper.
Dietmar Wueller Electronic Imaging Symposium 2026