My superbias looks wrong?

[Terry Danks]

Hi All:

I have watched Warren K.'s tutorial on superbias. My camera is a noisy STL-11002XM.

I took 50 bias frames, integrated them and applied PI's Superbias using 6 layers(not the default 7 as I was using 50 frames), as per the tutorial.

The resulting superbias looks good, well quite indistinguishable from the regular bias, really.

But when I do the subtraction of the superbias from the regular bias, again as per the tutorial, I get the result in the screenshot.
According to the tutorial, "only randomly distributed noise should remain." Not what I have at all.
The 24-bit LUT setting for the STF was applied to the pixel math result in the screenshot.

Suggestions as to what I have done wrong would be appreciated.

Terry

[MikeOates]

Terry,

As far as I am aware the superbias does not yet work well with sensors that have columns that are not fairly even along their length. This is what you are probably seeing when you subtract the superbias from a regular bias.

This is a quote from Juan: (http://pixinsight.com/forum/index.php?topic=7266.0)

Bias frames with partial columns are still not supported by the Superbias tool. Sorry for the inconvenience. We'll release a new version to overcome this limitation, but probably not before September.

I don't know how far off this update is.

Mike

[Terry Danks]

Many thanks for that link, Mike. I have not been keeping up, it seems.

Close examination of the super and master bias frames clearly shows vertical columns that were partial in the master became full height in the
resulting super. Otherwise the super was clearly smoother with a less grainy appearance.

Seems that the super process is not right for my STL and I will have to wait for the update.

Terry

[Warhen]

Terry, I'm using an 11002 also, and get the result you do. That being said, the resulting Lights calibrated with the super bias read as significantly lower in noise than with just a straight bias. So, I'm sticking with the SB!