SKYSAMPLER
Purpose :
Statistical analysis of the pixel values to find the sky
background level across the plate.
Procedure :
The image is divided up into a grid of cells and the density
histograms accumulated for each cell. Within each cell the
pixel statistics are computed including mean, rms and fiducials.
These results are saved as a data cube as (x,y,stats)
where the stats are :
- stats(1) : Mean
- stats(2) : St.Dev.
- stats(3) : Min.
- stats(4) : 10%
- ...
- stats(12): 90%
- stats(13): Max.
This is saved as a SIM (Sky IMage) file along with a (Sky Image Header) SIH
file which contains the data cube dimensions and sampling size.
Calling Sequence :
- SKYSAMPLER imagefile
- [/XRANGE=(lx,ux)] Area to analyse {default is entire image}
- [/YRANGE=(ly,uy)] Area to analyse {default is entire image}
- [/SAMPLESIZE=n] Grid size in mm {default 0.5mm}
- ***** NOTE: ONLY USE DEFAULT SAMPLESIZE UNTIL FURTHER NOTICE ****
- [/FIDUCIALS=n] No.Fiducials to calculate {default 10}
- useful range: min: 1 max: 100
- [/BIN_SIZE=n] Binning of ADC values {default 16}
- useful range: min: 10 max: a few hundred
- [/COMMENT="String"] Comment for DID file
- [/[no]ANNOTATE] Write results
- [/NEW] Write new DID file
- [/DEBUG]
Availability :
- GSSS AXP - yes
- GSSS VAX - yes
- PIXELS - no
History/Author :
Original Implementation - Brian McLean
Brian McLean ---- mclean@stsci.edu