Axis communications have given guidelines on minimum operational requirements of a camera to allow a human observer to identify, recognise, and detect human subjects (https://www.axis.com/en-ca/learning/web-articles/perfect-pixel-count/pixel-density). They have cited the Swedish National Laboratory of Forensic Science, and IEC International Standard IEC 62676-4 in explanation of their recommendations, however i cannot find these specific texts.
Are there any peer-reviewed studies that observe the effects of the pixel density of an image on a person's ability to identify, recognise, and detect human subjects (specifically facial)?
I have searched various sources, but only seem to find results that address image resolution and face-detection software efficacy.