Bad column of pixels

Edward Lubat

Hi Adam,

I am doing some practice processing on a dataset from Telescope Live.  A CCD camera was used that seems to have a bad column of pixels.  I vaguely recall one of your earliest videos giving instructions on how to deal with this, but I can't find it.  Am I correct?  If so, could you point me to it?  Small screenshot attached.  Thanks

Ed

BlockHead

A couple of points.

1. If you have many frames and the dithering is good- it might not be an issue. But it depends.

2. You are probably thinking of using Defect Map. Indeed, this is a pretty strong solution especially if he columns really do go across the frame. You would create a defect map (step 1)... then apply it to all of your calibrated frames (non-registered). The bad column would be in the same position. Use an ImageContainer to easily do this job in seconds.

-the Blockhead

BlockHead

Specifically

https://www.adamblockstudios.com/articles/Workflow_DefectMap

Edward Lubat

Thanks.   That video shows you employing the defect maps to correct the images.  But do you know which video shows you creating those defect map files (I looked earlier in that workflow series, but you already had the 2 defect maps ready from the get-go)?

Ed

BlockHead

Hmmm... I have that somewhere... probably in a Pixel Math video.

It is easy.

1. Open one of your dark frames (or light frames)

2. Identify the columns you want to correct or map.

3. Using pixel math create black lines on a white image. An expression for a single column is

iif(x()==2346,0,$T)

This will create a black line at y=2346. Note that I used $T. If you start with a white image will be adding columns (and not overwriting one previous one you made).

-the Blockhead