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HDR - THE REALITY & ASSOCIATED ISSUES The biggest issue with HDR displays is they can actually be painful to watch, due to what is often termed as excessive eye fatigue... The problem is the difference between the human eye's huge Dynamic Range, which has a dynamic contrast ratio of around 1,000,000:1, or about 24 stops, and the eye's static dynamic range. It is the eye's dynamic adaptation capability that enables us to see detail in dark environments, as well as in bright sunlight. However, at any single given time the human visual system is only capable of operating at a fraction of this huge range. It is this static dynamic range, which occurs when the human visual system is in a state of full adaptation, that is active when watching home TV and some theatrical presentations at 'normal' viewing distances. While there are few exact figures for the human eye's static dynamic range, many agree it is around 10,000:1, for average viewing environments, which is around 12 Stops. 
Additionally, the human visual systems adaptive response needs to be taken into consideration - the time it takes to adapt between dark scenes to bright scenes, and vice versa, with bright to dark transitions typically taking many minutes to adapt, while dark to bright adaptation is significantly quicker, but still often measured in many 10's of seconds, if not minutes. This is easy to experience by looking out a windows from within a dark room, and panning your eyes from the window to within the room. The room detail slowly resolves itself as the eye adapts to the change in brightness. Further, with the relatively small size of TVs, combined with the standard viewing distance - 3m or so - the whole TV screen is within the high-acuity, central angle of view of the human eye (5° to 15°), meaning the human visual system cannot respond independently to different areas of brightness - being stuck within a state of full adaptation, so the viewer is only able to use the static dynamic range of the human eye. To actually gain benefit from the concept of HDR the actual viewing angle the display would need to occupy would be in the order of 45°, which with an average large TV of 55" would means sitting just 65" from the screen.
(See also the section on 'Resolution'.) Do you really sit this close to your TV? What all this really means is a display with an excessive HDR will potentially cause real eye fatigue at normal viewing distances, and will very likely be be painful to watch.
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發表於 2017-7-20 01:21
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