Astronomy and Astrophysics – Astrophysics – Instrumentation and Methods for Astrophysics
Scientific paper
2009-10-23
Astronomy and Astrophysics
Astrophysics
Instrumentation and Methods for Astrophysics
Revision includes comparison with linear (decimation) compression schemes
Scientific paper
We investigate data compression schemes for proposed all-sky diffraction-limited visible/NIR sky surveys aimed at the dark energy problem. We show that lossy square-root compression to 1 bit of noise per pixel, followed by standard lossless compression algorithms, reduces the images to 2.5-4 bits per pixel, depending primarily upon the level of cosmic-ray contamination of the images. Compression to this level adds noise equivalent to <10% penalty in observing time. We derive an analytic correction to flux biases inherent to the square-root compression scheme. Numerical tests on simple galaxy models confirm that galaxy fluxes and shapes are measured with systematic biases <~10^{-4} induced by the compression scheme, well below the requirements of supernova and weak gravitational lensing dark-energy experiments. An accompanying paper (Vanderveld 2009) bounds the shape biases using realistic simulated images of the high-Galactic-latitude sky. The square-root preprocessing step has advantages over simple (linear) decimation when there are many bright objects or cosmic rays in the field, or when the background level will vary.
Bebek Chris
Bernstein Gary M.
Rhodes Jason
Stoughton Chris
Vanderveld Ali R.
No associations
LandOfFree
Noise and bias in square-root compression schemes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Noise and bias in square-root compression schemes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Noise and bias in square-root compression schemes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-424138