HDR: Does Pupil Variability Cause Excruciating Agony?

Pupillometry of HDR Video Viewing. Scott Daly, Evan Gittermana, and Grant Mulliken. Dolby Laboratories, Inc., San Francisco, CA, USA Apple, Cupertino, CA, USA

An excellent study by researchers from Apple and Dolby Laboratories investigates a common assumption that increased pupil variability causes discomfort while consuming HDR content.

“There is a natural inclination to liken the visual system to camera engineering. The common misunderstandings also include assumptions of linearity. For example, in a comparison of viewing a 1000 cd/m2 HDR with viewing a 100 cd/m2 SDR display, a common expectation is that the viewers’ pupil areas would compensate for the light level differences with the result that the Area SDR ~ 10x Area HDR.

This expectation is consistent with the common over-simplification that “HDR is all about brighter pictures”. That is, the higher maximum luminance capability of HDR leads to pictures that are overall brighter, and using quantitative terminology, HDR results in a higher ADL (Average Displayed Luminance). Of course, that oversimplification doesn’t consider distinctions between maximum diffuse white, peak luminance, the role of specular highlights in evoking realism, and interscene dynamic range.”