Also if the Pixel size is smaller than the wave length of light that one
is attempting to captured, you'll miss an awful lot of light in that
wavelength. (I'm not sure how perverse the universe is, I'm betting on
maximum amount of perversity here, in that if what will benefit more one
more in this case is if light works as a packet, so of course here it
will act as a wave.
On 10/10/2015 12:58 AM, Igor PDML-StR wrote:
Larry, I've had that hypothesis (in the back of my mind) for a while.
Your question made me thinking in more detail about it.
On one hand the argument for why that should be possible is as follows:
If the noise is due to the statistical uncertainty (Sqrt(N)) for the
number of counts (N) on the detector (pixel in this case), and the
number of counts scales with the area of the single detector (pixel),
then by combining the output of the equivalent number of the detectors
(or more exactly, areal coverage), we should obtain a comparable level
of the noise to that of a large detector of the same area.
(For simplicity, let's neglect for now the "wasted" area between the
smaller pixels that is not occupied by the pixel.)
However, that doesn't cover other (numerous) sources of noise that scale
differently (or even don't scale at all) with the sensor size.
Dissertations are written on very careful analysis of those.
(If you are interested, - look e.g. at these class notes:
https://classes.yale.edu/04-05/enas627b/lectures/EENG427l09bnoise.pdf )
But I can think of two "phenomenological" examples that demonstrate
why the sum of smaller sensors might not be as good as a single large
one.
1. A smaller sensor might require a fundamentally different design,
which, in turn, produces a different level of noise (e.g. CMOS vs CCD).
2. If noise is generated at the boundary of the sensor. (This could
be relevant for very high-density/small pixel size sensors)
Then the combined boundary length (circumference) of the M smaller
pixels covering the same area as one large pixel will be Sqrt(M) times
larger then that of that single large pixel.
I am not sure if this type of "boundary" noise is actually
happening/important in today's sensors. It might be that this type of
effects are only relevant for much smaller (e.g.
double-digit-nanometer-scale electronics) devices.
But in any case, - different scaling of different types of noise
(noise sources) and different relative contribution from different
sources at different pixel sizes can create the situation when you
might not get a low-light-level noise from the combined pixels of a
high-pixel-density camera sensor as low as you would get it from an
equivalent-pixel-count lower-pixel-density camera sensor.
Igor
Larry Colen Fri, 09 Oct 2015 14:10:38 -0700 wrote:
That being said, I don't understand why with a bit of math a 42 MP
sensor could not put out 12 MP files with the same noise and DR as the
12 MP sensor. My feeling is that you could probably come pretty close
to the noise of the 12 MP sensor, while still retaining most of the
resolution of the 12 MP sensor, particularly for high contrast edges.
--
I don't want to achieve immortality through my work; I want to achieve
immortality through not dying.
-- Woody Allen
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