Bad Pixel Correction

Usually, a detector array has a few bad pixels which do not have proper working conditions. The detector of the echelle section of IRCS has bad pixels less than $\sim$0.7 percent. The bad pixel mask was made of replacing the pixel values of dark and normalized flat frames by 1 for bad pixels and 0 for good pixels. Most bad pixels usually have too high or low pixel values, so one can pick them out and replacing their pixel values by using IMREPLACE task with adjusting its `upper' and `lower' parameters. Several bad pixels which could not be picked out by IMREPLACE task can be added to the bad pixel image manually with TVMARK, TEXT2MASK, and ADDMASK tasks (see, Figure 36). Figure 37 shows the bad pixels on the detector of the echelle section.

The FIXPIX task is used to correct badpixels.

  

  

Figure 36: An example procedure for making a bad pixel mask and correcting bad pixels on an object.imh.

Figure 37: Bad pixels on the detector of the echelle section of IRCS. Black dots and lines are the bad pixels.