The Hubble Deep Field -- version 2 S/N

Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/ftp/science/hdf/archive/snv2.html
Дата изменения: Thu Feb 13 21:56:57 1997
Дата индексирования: Sat Dec 22 22:53:01 2007
Кодировка:
Поисковые слова: annular solar eclipse

HDF version 2 noise properties

The attached figures compare the rms fluctuations of the sky background measured in blank regions of the final drizzled images from version 1 and version 2 of the HDF data reduction. The images have been successively binned 2x2, 3x3, up to 16x16 pixels to highlight the fact that the images are smoother on pixel scales than would be computed from a naive application of the CCD noise model. This is because the image combination process produces correlations between neighboring pixels.

The figures show the rms fluctuations divided by sqrt(N) where N is 2 for 2x2 binning, 3 for 3x3 binning, etc. If the noise were uncorrelated there would be no change in the rms with N.

The open circles show version 1 of the data, with the dashed line showing the best estimate of the mean for N>6. The filled circles show version 2 of the data, with the solid line corresponding to the best estimate of the mean for N>6.

F300W

F450W

F606W

F814W

Harry Ferguson ferguson@stsci.edu 3/01/96