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Very interesting. However this only tells half the story about human vision, what about color depth, dynamic vision range, and speed (flash something fast on sc

Very interesting. However this only tells half the story about human vision, what about color depth, dynamic vision range, and speed (flash something fast on screen)?

jhonovich 13y ago
Agreed. In this test, we were just looking at making out details. I would certainly not say a 10MP IP camera is equal overall to the human eye. Indeed, to the contrary, the poor low light performance of the 10MP compared to the human eye is just one example of the tradeoffs of cameras to eyes.
sp332 13y ago
The concepts don't map directly. The retina has a "static" contrast ratio of about 100:1 or 6.5 f-stops. However, the iris can change the amount of light that enters the eye, and the retina can change its sensitivity, so in practice it's more like 14 f-stops quickly and 20 f-stops if you let your eyes adjust for a while. That's not even counting the fact that your fovea has lots of cone cells while your peripheral vision has more rods, which is why looking next to a star makes it look brighter than looking right at it. Persistence of vision means that flashing something on the screen is almost meaningless. All that matters is how much light energy is pulsed into the eye, creating an afterimage.
Someone 13y ago
Half? More like 1% or less. Dynamic range is incredible (1,000,000:1 according to http://en.wikipedia.org/wiki/Human_eye#Dynamic_range http://en.wikipedia.org/wiki/Human_eye#Dynamic_range), one should test vision in darkness peripherally (rods have lower resolution, but higher sensitivity than the cones in the fovea. There are claims humans can see individual photons), etc. Even limiting one to these experiments, test subjects should dark adapt for at least one hour before a measurement (given that te article doesn't mention it, I think it is unlikely that was done). That can make a huge difference. Some (and more, including "The brain contains 10^12 neurons, 10^14 of which are in the cerebellum.") of the numbers you ask for are in http://white.stanford.edu/~brian/numbers/node2.html http://white.stanford.edu/~brian/numbers/node2.html
- Sharlin 13y ago
  The 1,000,000:1 (20 EV) dynamic range is not that incredible when taking into account that it's dynamic, not static - it's the sensitivity difference between fully dark-adapted and direct sunlight, not the ratio of maximum and minimum luminance that can be simultaneously perceived. My DSLR can do more than 20 EV of dynamic contrast ratio quite easily: first, it has a static contrast ratio of at least 8 EV (a conservative estimate); most lenses have about 7 stop difference between their minimum and maximum aperture; and my camera's ISO sensitivity range is 100 to 12800, that's another 7 stops. Together, these add up to 22 EV (a ratio of 4,200,000 to 1!) A high-end camera could probably easily reach 26 or 28 EV. And cameras don't need to a hour-long adaptation period.
- nitrogen 13y ago
  Is the neuron number meant to be a joke, or is the 10^14 being greater than 10^12 a typo?
  - Someone 13y ago
    It is a joke, and an indicator of how little we really know. In the same vein, that text has: Number of neurons in the brain in 1974: 10 billion Number of neurons in the brain in 1994: 100 billion (Wikipedia gives 85 billion on http://en.wikipedia.org/wiki/List_of_animals_by_number_of_neurons http://en.wikipedia.org/wiki/List_of_animals_by_number_of_ne...)

Very interesting. However this only tells half the story about human vision, what about color depth, dynamic vision range, and speed (flash something fast on screen)?

jhonovich 13y ago

Agreed. In this test, we were just looking at making out details. I would certainly not say a 10MP IP camera is equal overall to the human eye. Indeed, to the contrary, the poor low light performance of the 10MP compared to the human eye is just one example of the tradeoffs of cameras to eyes.

sp332 13y ago

The concepts don't map directly. The retina has a "static" contrast ratio of about 100:1 or 6.5 f-stops. However, the iris can change the amount of light that enters the eye, and the retina can change its sensitivity, so in practice it's more like 14 f-stops quickly and 20 f-stops if you let your eyes adjust for a while. That's not even counting the fact that your fovea has lots of cone cells while your peripheral vision has more rods, which is why looking next to a star makes it look brighter than looking right at it. Persistence of vision means that flashing something on the screen is almost meaningless. All that matters is how much light energy is pulsed into the eye, creating an afterimage.

Someone 13y ago

Half? More like 1% or less. Dynamic range is incredible (1,000,000:1 according to http://en.wikipedia.org/wiki/Human_eye#Dynamic_range http://en.wikipedia.org/wiki/Human_eye#Dynamic_range), one should test vision in darkness peripherally (rods have lower resolution, but higher sensitivity than the cones in the fovea. There are claims humans can see individual photons), etc. Even limiting one to these experiments, test subjects should dark adapt for at least one hour before a measurement (given that te article doesn't mention it, I think it is unlikely that was done). That can make a huge difference. Some (and more, including "The brain contains 10^12 neurons, 10^14 of which are in the cerebellum.") of the numbers you ask for are in http://white.stanford.edu/~brian/numbers/node2.html http://white.stanford.edu/~brian/numbers/node2.html

Sharlin 13y ago
The 1,000,000:1 (20 EV) dynamic range is not that incredible when taking into account that it's dynamic, not static - it's the sensitivity difference between fully dark-adapted and direct sunlight, not the ratio of maximum and minimum luminance that can be simultaneously perceived. My DSLR can do more than 20 EV of dynamic contrast ratio quite easily: first, it has a static contrast ratio of at least 8 EV (a conservative estimate); most lenses have about 7 stop difference between their minimum and maximum aperture; and my camera's ISO sensitivity range is 100 to 12800, that's another 7 stops. Together, these add up to 22 EV (a ratio of 4,200,000 to 1!) A high-end camera could probably easily reach 26 or 28 EV. And cameras don't need to a hour-long adaptation period.
nitrogen 13y ago
Is the neuron number meant to be a joke, or is the 10^14 being greater than 10^12 a typo?
- Someone 13y ago
  It is a joke, and an indicator of how little we really know. In the same vein, that text has: Number of neurons in the brain in 1974: 10 billion Number of neurons in the brain in 1994: 100 billion (Wikipedia gives 85 billion on http://en.wikipedia.org/wiki/List_of_animals_by_number_of_neurons http://en.wikipedia.org/wiki/List_of_animals_by_number_of_ne...)