biasredux -- compute initial standard CCD-reduction and creates an error-frame


biasredux [flags] images

gain g 1.0
lower l 0.0
mask m
masterbias b
mbiasnan n -1e10
reg r 0:0,0:0
satur s 61000.0,1
shutter h
tresh t 54000.0


gain = 1.0
Conversion factor: # photons = gain * ADU
lower = 0.0
Lower threshold [ADU]: all Pixels below this value are set to "0".
If a bad-pixel-mask is specified, all pixels with value "0" in the mask are set to value "0" in the images.
If a masterbias is specified, it is subtracted pixels by pixel.
mbiasnan = -1e10
Nan value in masterbias.
reg = 0:0,0:0
Overscan region: x1:x2,y1:y2
satur = 61000.0,1
Saturation threshold [ADU]: all Pixels above this value are set to "0". The second number specifies a radius for masking neighbouring pixels (blooming correction).
Filename of shutter correction file.
thresh = 54000.0
Linearity threshold [ADU]: all Pixels above this values are set to the value "0".
Images to be processed.


The task biasredux is doing the initial CCD-reduction. First, bad pixels (mask-flag), nonlinear pixels (thresh-flag) and saturated pixels as well as their neigbouring ones (satur-flag) are masked (set to the value "0"). After that a bias correction is made. For this step a either a masterbias image (masterbias-flag) or an overscan region (reg-flag) has to be specified. Using the -h flag, biasredux is doing a shutter correction. The given file must be in FITS-format. For each image biasredux will create an errorframe based on photon noise calculations.


bias reduced and masked image
errorframe of bias reduced and masked image


biasredux -g 3.35 -m Mask_WST.fits -h sdyshutter_WST.fits -r 150:950,2:14 -s 65000,2 -t 64000 F1_r_*.fits

Task index
This task was implemented by A. Riffeser
Dokumentation maintained by J. Koppenhöfer
This file was last time updated on 21 Feb 2005