Bad Pixel Correction

The CCD package includes possibilities, before doing the actual calibration step(s), to correct for bad pixels in the CCD calibration frames. This correction is applied via the command FIXPIX/CCD and based on existing MODIFY commands. Except for the input and output frame the FIXPIX/CCD command accepts two more parameters in the command line: the correction method to be applied and the MIDAS table containing the bad pixel(s) of bad pixel areas(s). Default value for these two parameters are stored in the keywords FX_METH and FX_FILE. In addition to these keywords three other keywords exist to control the correction procedure: FX_FACT, FX_FPAR, and FX_NOISE. The use of these keywords depends on the correction method applied.

Currently, the required format of the table file depends on the correction method to be applied. Below you can find a listing of the method available and with FX_ keywords involved.

• method area (MIDAS commands MODIFY/AREA):
  parameter degree taken from keyword FX_FPAR(1);
  parameter constant=0.
• method pixel (MIDAS command MODIFY/PIX):
  parameter arfacts taken from keyword FX_FACT;
  parameter xdeg,ydeg,niter taken from keyword FX_FPAR;
  parameter noise taken from keyword FX_NOISE.
• method column (MIDAS command MODIFY/COLUMN):
  parameter col_type=V.
• method row (MIDAS command MODIFY/ROW):
  parameter row_type=V.