Author Topic: Modified Canon 450D Pixinsight Troubles  (Read 4555 times)

Offline FuriousRabbit

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Modified Canon 450D Pixinsight Troubles
« on: 2012 October 25 05:11:59 »
I'm really trying to get a grasp on this software as I can see the power and MANY options it has but I'm having a terrible time with my trial. I've watched numerous videos but I'm still struggling to get this workflow working with my DSLR camera.

I use Nebulosity to capture all of my light/dark frames in fits format. I've been using the batch preprocessing script in Pixinsight with much success to get my master light, this is where I start to get confused since most of the videos out there are catered toward people with CCD's. I open the master light and since I have a modified dslr the image has a redish hue ...in Nebulosity this isn't a problem i can simply use the color correction option and it sets the image to the correct color and I can happily continue post processing. I'm at a loss with how this is acheived in Pixinsight. Does anyone know where I can get a good tutorial for dslr processing? I've seen the one on the forum but that seems to cater to people using raw format ....

Offline georg.viehoever

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #1 on: 2012 October 25 07:44:07 »
Welcome to PI!

1. Try the Batch Processing Script (part of PI installation) and discussed here http://pixinsight.com/forum/index.php?topic=3654.450
2. If you prefer manual work, see here http://pixinsight.com/forum/index.php?topic=2570.0
3. Did you try to use the "Search" button on the top right of the forum screen   O:)

Georg
Georg (6 inch Newton, unmodified Canon EOS40D+80D, unguided EQ5 mount)

Offline NGC7789

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #2 on: 2012 October 25 08:14:51 »
Once you have completed your pre-processing and have a master light there really isn't much difference between dslr and other processing.

That being said, see the top pinned thread in the Tutorials forum.

ruediger

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #3 on: 2012 October 25 08:23:20 »
since I have a modified dslr the image has a redish hue
I guess you are using the Screen Transfer Function with coupled channels. Once you uncouple the channels and hit "A(uto", redish hue should be gone. You should then continue with Background Extraction, Background Neutralization and Color Balance.

RĂ¼diger

Offline FuriousRabbit

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #4 on: 2012 October 25 10:33:39 »
since I have a modified dslr the image has a redish hue
I guess you are using the Screen Transfer Function with coupled channels. Once you uncouple the channels and hit "A(uto", redish hue should be gone. You should then continue with Background Extraction, Background Neutralization and Color Balance.

RĂ¼diger

This little piece right here maybe what I was missing. I was using the 'Auto' function with the channels linked!  I'll dive in deeper tonight and see what I get.

Offline pfile

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #5 on: 2012 October 25 16:36:24 »
the 'uncoupled channel' autoSTF is very useful for seeing what your data 'really' looks like.

if you are happy with it, i suppose you can just transfer the autoSTF settings to the HistogramTransformation tool, thus stretching your image. this is done by dragging the STF triangle to the strip at the bottom of the HT tool (where the HT tool's triangle, etc. live, but don't drag onto those icons or it won't work), and then applying the HT to your image.

having said that, here are a couple of caveats:

1) one usually needs to run DBE on the stacked image, since invariably there are always gradients. if you have run DBE with 'normalize' unchecked (default), it will have the effect of roughly aligning the channels.

2) probably ColorCalibration should be used to fix your color balance after DBE. I think one should run BackgroundNeutralization before running CC.

3) there are a lot of ways to stretch an image (AdaptiveStretch process, MaskedStretch script, HistogramTransformation). you may not want to use HT to do the initial stretch in favor of MaskedStretch.

the processes in point #2 require careful tuning of the high/low pixel value parameters to make sure you are only picking up the pixels you are interested in. if you want to spatially constrain the pixels the processes are looking at, define previews in the areas you are interested in, but then use the Region of Interest setting and take the coordinates from the preview ("from preview"). if you save a process icon for CC, this will make it portable to another image without having to remember where to create previews and update the process to point to the new image's previews. this is useful if you add integration time to an image and you want to re-do all your processing.


Offline FuriousRabbit

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #6 on: 2012 October 26 05:35:50 »
Thank you all for the tips. After slamming my head against the keyboard a couple of times, getting frustrated to the point of uninstalling a few times, I think I'm getting the swing of things.  :P

I'd like to post my processed image since I have some questions still. When I tried to save my image as a png I get the following message: "The png format does not support the sample data type used by this image." Any idea what would be causing this? I have also tried in other image formats besides fits and receive the same message?

Offline pfile

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #7 on: 2012 October 26 17:01:48 »
PI uses 32-bit floating point numbers internally. png is very likely an 8-bit per channel format, like jpg.

in the case of jpg, PI still saves the file with the warning that unless you save it in a format that supports floating-point 32 bit numbers, you are going to lose your 'true' data. i'm not sure what happens with png - does it refuse to save the file? anyway, it might have still saved the file, check for the file on disk...

Offline FuriousRabbit

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Re: Modified Canon 450D Pixinsight Troubles
« Reply #8 on: 2012 October 29 06:47:52 »
Got it. Yeah I was more wondering why the error message was occurring. Thanks again!