H**d
发帖数: 25 | 1 Copied from my book:
In 1942 Hecht, Shlaer and Pirenne measured the absolute sensitivity of
the human visual system. They adapted subjects to darkness so that the
rod receptors were in a state of maximal sensitivity, and presented
brief flashes of blue-green light, which were focused on the retina and
progressively dimmed until the subject reported seeing them only 60%
of the time. Then they measured how many quanta of light feel on the
eye during each threshold flash and estimated the number of |
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