Astra Image LR Deconvolution - What the???

[Robert_T]

Does this happen to anyone else using Astra Image LR deconvolution. For some reason I get wildly varying results - especially brightness.

I bring in my planet shots, split the colour into B&W and process separately using LR deconvolution before combining. Generally when running LR deconvolution (usually 3-4 iterations at 1.5 -1.7 curve) the results for each colour come up about the same brightness or a little darker than the originals. Recently though (but not always and I can't see a pattern) the results are coming out so Dark as to be useless.

Any ideas

[davidpretorius]

i also have noticed a darkening sometimes, not all the time.

there is a histo stretch at converting to greyscale time???


bird????

[iceman (Mike)]

It definitely does a histo stretch when you either a) convert to greyscale or b) split colour planes

Sometimes it doesn't appear to brighten until you click on the window.

The results come out darker if you do a lot of iterations, I've found. And even darker still if you use a resample in registax.

[Robert_T]

I wonder if it darkens more if a Histo-stretch has already been done in Registax (sometimes I do, sometimes not)? I'll try a test.

I've noticed it darkens with more iterations, but this is something else. I can run just two iterations now sometimes and get VERY dark images resulting?

cheers,

[bird (Anthony Wesley)]

You've probably got some bright pixels around the edge of the image you imported - try cropping the image back a few pixels from all edges and try again.

If there are any isolated bright pixels then deconvolution will turn them into a bright white point, and then the automatic histo-stretch in astra image will make the rest of your image darker.

regards, Bird

[Robert_T]

Originally Posted by bird

You've probably got some bright pixels around the edge of the image you imported - try cropping the image back a few pixels from all edges and try again.

If there are any isolated bright pixels then deconvolution will turn them into a bright white point, and then the automatic histo-stretch in astra image will make the rest of your image darker.

regards, Bird

Thanks Bird, makes sense I'll give that a try. At a loss for any other explanation, the last avis I took had no problem.

cheers,

[Robby]

LR deconvolution tries to optimise out the imperfections in the optical path, by analysing each star image know that it should be a pin-point.
Frow what I understand LR only works properly on "RAW" images. That is those that have had no jpeg (or other) compresion. With compression the optical information is generally lost, so LR is less beneficial.
However many have had success with LR's on Jpegs (iceman ext). It may be possible that remnants for the optical imperfections are still there and can still improve an image.
I have only tried LR on "RAW" images so can't really comment any further!
Cheers