Bad pixel map

Hi Donghun,

Thank you for your question,

Depending on the sensor it can vary quite a lot what % of hot pixels would be a good value. It can range from roughly 0.05% to 5%.

If you load a light frame and the bad pixel map, you can check how effective it works by viewing the light frame with the linear(l) and the l-calibrated image viewer modes.

First, deselect the "scale" selectbox above the image viewer. This box means "scale to fit". So by deselecting, you will preserve the zoomfactor and the scrollbar positions of the image viewer panel.

Set the image viewer mode at linear(l):

If you have bad columns and/or a lot of bad pixels, try to zoom in on an area of the light frame where you see these bad colomns and or hot pixels clearly. Possibly adjust the stretch parameters(on the right, below the histogram) to have a better visual look.

Then set the image viewer mode to the l-calibrated mode (above the image viewer window):

The light frame will be loaded again and will be calibrated by the Bad Pixel Map. You can now visually check if the Bad Pixel Map is correcting all bad columns and/or bad pixels. If there are still bad pixels left, make a new bad pixel map with a lower kappa value than the previous one. So it's a bit of trial and error to get a bad pixel map that corrects all the artefacts that you want to remove. And don't be afraid to be a bit aggresive in lowering the kappa value.

Let me know if this works for you.

Kind regards,

Mabula

Hi Mabula

Ok I will start with a high kappa value and reduce the value until I don't see any hot pixel and column artifacts.

Thank you very much.

Donghun