Re: In-camera noise FILTERING is a disaster, in most cases

On Dec 20, 7:01 am, Scott W <biph...@xxxxxxxxxxx> wrote:
On Dec 19, 4:50 pm, RichA <rander3...@xxxxxxxxx> wrote:

I'm not referring to it as NR or noise reduction because it isn't the
same thing. NR is "dark frame subtraction" and is used when exposure
times are longer than 1 second and heat build-up in the sensor creates
noise.

There is no heat build up for a long exposures, the noise is from dark
current.

Yes, there is, which is why scientific users either use Pelltier
coolers or dry ice, or liquid nitrogen to cool the sensors for long
exposure work (or IR work).
http://www.regulusastro.com/regulus/papers/ccdfaq/index.html

"Thermal control of an imager's chip allows one to significantly
reduce the amount of dark signal (thermal signal) produced within the
CCD chip itself. In the chip the actual substrate materials actually
vibrate due to heat, and create electrons in the photosites."
.

Relevant Pages

  • Re: CMOS vs. CCD -- Link to Article
    ... since the reason the Canon cameras ... >>data on the rate the noise grows with time for each pixel, ... There is a dark ... > a long exposure, measure the noise, and square that value. ...
    (sci.astro.amateur)
  • Re: In-camera noise FILTERING is a disaster, in most cases
    ... NR is "dark frame subtraction" and is used when exposure ... There is no heat build up for a long exposures, the noise is from dark ... the ambient temperature of the chip, ...
    (rec.photo.digital.slr-systems)
  • Re: In-camera noise FILTERING is a disaster, in most cases
    ... NR is "dark frame subtraction" and is used when exposure ... There is no heat build up for a long exposures, the noise is from dark ... the ambient temperature of the chip, ...
    (rec.photo.digital.slr-systems)
  • Re: CMOS vs. CCD -- Link to Article
    ... >data on the rate the noise grows with time for each pixel, ... >will perform an automatic dark subtraction), ... >'dark' from these numbers, and subtract it. ... a long exposure, measure the noise, and square that value. ...
    (sci.astro.amateur)
  • Re: In-camera noise FILTERING is a disaster, in most cases
    ... NR is "dark frame subtraction" and is used when exposure ... There is no heat build up for a long exposures, the noise is from dark ... the ambient temperature of the chip, ...
    (rec.photo.digital.slr-systems)