Roger N. Clark (change username to rnclark) wrote:
Alan Browne wrote:

(and our cameras will be imaging spectrometers too). Oh, and make
read and thermal noise zero.


Boltzman says no-can-do. You could always add heat removal but it's
unlikely that you can cool an entire portable camera sensor to milli-K
levels.


It need not violate any physics,

I didn't say "violate" just that you need very low temps...

and I should have said
effectively zero, not absolutely. Read noise in the
best consumer cameras is already under 4 electrons
at room temperature and reports are reportedly even lower
in the 1D Mark III. With more accurate 18-bit converters
and on-pixel electronics, 1 electron read noise is possible.

I was under the impression that absent very cold temps, that noise
(thermal at least) is simply unavoidable. If 18 bits/channel is
achieved and you throw away a couple/3 bits per channel for noise, then
whatever is left should be quite clean indeed.

Thermal noise keeps getting better with each generation
sensor. Cooled CCDs reached the level of one electron/hour thermal
dark current a long time ago, and DSLR CMOS dark currents are
less than a thousand electrons/hour already at ambient temperatures
(and noise is square root dark current). These are great values
already, even without any improvements!
Line and pixel uniformity is improving too with each generation,
but is already outstanding. Most digital camera imaging
has noise limited by photon noise, not other sources, so even
with improvements, most images will see little difference.


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