Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_dslr_mirrorlesss_winners.thumb.jpg.9deb4a8db27e7485a7bb99d98667c94e.jpg

Altais

New software: Astrophotography Lab

Recommended Posts

Good day everyone. :)

I've been working on a programming project for some time now. It started up as a simple SNR calculator in excel, but after a while I started thinking that it would be useful to have a graphical user interface with some more options, like choosing different cameras and showing graphs.

As of now the program can calculate sensor data like gain and read noise automatically when provided with some bias and flat frames, and the data can be saved in one of the included camera profiles. This information can further be used to calculate SNR, dynamic range, skyglow, dark noise etc. in provided images. There is also a tool that generates a synthetic image for given camera settings and imaging conditions. Finally the program can plot graphs describing how image quality will vary when a certain parameter is changed.

Here are a couple of screenshots:

post-43721-0-33063900-1437839922_thumb.p

post-43721-0-77897500-1437839840_thumb.p

There are included camera profiles many CCD and DSLR cameras, but any camera that can save raw images can be used.

A more detailed description, more screenshots and the download link can be found here: http://oaltais.github.io/aplab/.

I would be very pleased if anyone wants to try it out and tell me what they think.

Clear skies,

Lars

  • Like 8

Share this post


Link to post
Share on other sites

Looks interesting - have downloaded it and will have a play when I get a minute :)

Thanks for your efforts!

Louise

Share this post


Link to post
Share on other sites

Hi Lars,

I've had a quick play with your software and I must say that I'm impressed. To say it's the easiest, quickest and cleanest way of analyzing your chip is an understatement.

When I've time I'll test it further but the readings are more or less what I remember from when I last tested the chip.

It's something everyone should now use. The surest way of finding out if you have a duff chip / electronics or not ! One reading is worth a thousand guesses eh ?

Dave.

Share this post


Link to post
Share on other sites

Looks really good!! And that's something I was looking for to analyse my cameras.

Thank you for sharing!

Enviado desde mi Aquaris E5 mediante Tapatalk

Share this post


Link to post
Share on other sites

Thanks everyone for giving it a try! :) Please let me know if you have any issues.

I've just updated the webpage with some more info.

One of my main concerns when writing the program was to make it as user friendly and informative as possible, so that also people new to astrophotography could find use in it and maybe learn a thing or two. Also questions like "What ISO should I use?" might be a little easier to answer when you can just play around with it on your computer.

By the way, I'm open for adding more features or improving the existing ones if you have any suggestions.

  • Like 1

Share this post


Link to post
Share on other sites

Hi again Lars,

I've used a bit more of your program and I'm still very impressed with it.

A couple of ideas - You seem to have covered most things but there's one set of data that a few camera manufacturers use that doesn't appear, and that's db. Not a problem but useful to see sometimes. **

Another one is that it's so difficult to drawer a box round a background when you can't see where the background is ( Same for target signal and to some extent stars and hot pixels ) Would it be possible to add a screen stretch to the image display area or is that a step too far ?

I particularly like the way you've enabled transferring data from one page to another. Neat :)

So far I've only used the program with a mono CCD. I'll try and dig out my DSLR and run that through.

Cheers,

Dave.

** You show dynamic range as stops.

Edited by davew

Share this post


Link to post
Share on other sites

Thanks a lot Dave! It is very helpful that you give me feedback on the program, it is much appreciated.  :grin:

I have been working on implementing an automatic stretch of the displayed image, after Steve over at the Astronomy Forum pointed out the need for this as well. The stretching algorithm first clips both ends of the histogram, making the darkest pixels black and the brightest pixels white. It then performs a histogram stretch that makes the mean pixel value show as 25% gray. This seems to be sufficient to reveal the faint detail in a range of different images.

Adding the option to show the dynamic range in decibels is also a good idea, so I have implemented that into the program as well.

I just uploaded the new version of the program (v0.1.1) featuring these changes. The download button on the webpage now links to the new version.

Clear skies,

Lars

  • Like 1

Share this post


Link to post
Share on other sites

Just downloaded it and had a quick play with the Image Analyzer and SNR Calculator.

That screen stretch is very good but makes my darks look awful :) It looks about the right stretch from the two subs I've tried.

Also like the db addition now.

I'll carry on thinking !

Dave.

  • Like 1

Share this post


Link to post
Share on other sites

Just downloaded it and had a quick play with the Image Analyzer and SNR Calculator.

That screen stretch is very good but makes my darks look awful :) It looks about the right stretch from the two subs I've tried.

Also like the db addition now.

I'll carry on thinking !

Dave.

What makes the darks look awful? Care to post a screenshot? :)

Share this post


Link to post
Share on other sites

Fear not Lars. My darks make my darks look awful.

Hot pixels and ray hits, not your program.

Cheers,

Dave.

  • Like 1

Share this post


Link to post
Share on other sites

Hi Lars,

I don't know just how useful this would be but could your program yield FWHM average figures across the frame?  I often double check my FWHM using DSS. It does both average FWHM and " Score " This is a quick and simple way of seeing if the focus is wandering off during the night. I have no problems with camera lenses but do with my refactor.

Another thing. Could the program read the FITS header to get the exposure value ?

Neither are game changing so no worries.

Dave.

  • Like 1

Share this post


Link to post
Share on other sites

Fear not Lars. My darks make my darks look awful.

Hot pixels and ray hits, not your program.

Cheers,

Dave.

Haha, right.  :grin: Nothing the program can do about that I'm afraid.

Hi Lars,

I don't know just how useful this would be but could your program yield FWHM average figures across the frame?  I often double check my FWHM using DSS. It does both average FWHM and " Score " This is a quick and simple way of seeing if the focus is wandering off during the night. I have no problems with camera lenses but do with my refactor.

Another thing. Could the program read the FITS header to get the exposure value ?

Neither are game changing so no worries.

Dave.

Great idea, it would definitely be nice to be able to find FWHM values. I'l look into how I can implement that.

Just to make sure I understand what you mean, are you talking about the actual exposure value like in eV, or the exposure duration?

Share this post


Link to post
Share on other sites

I thought it may be a good idea for the program to enter the Exposure Duration in the SNR calculator, but only if it can read the FITS file. That way there's less chance of making an input error, especially if you're running through a few alternatives. ( I wasn't just being lazy - honest )

Dave.

Share this post


Link to post
Share on other sites

I have actually implemented this already in version 0.2.0.  :smiley: It will check the image metadata for the exposure time (and ISO value for DSLRs). If detected, this information will be transferred to the SNR calculator along with the other image data.

For FITS files, it currently looks for a tag named "EXPTIME" in the header. Do you know of any other tag names that are also used to indicate exposure duration?

Share this post


Link to post
Share on other sites

Partly from memory and partly from just checking I have seen, " Exposure " and " EXPOSURE "

I'll go and download 0.2.0 when you post it   :)

Dave.

Edited by davew

Share this post


Link to post
Share on other sites

Partly from memory and partly from just checking I have seen, " Exposure " and " EXPOSURE "

I'll go and download 0.2.0 when you post it   :)

Dave.

Thanks, I'll make it check for those tags as well. Might be a while before v0.2.0 is ready for release. Many features to add.  :grin:

Hi Lars, will it run ok on OS X?

Hey Chris. At the moment it will not work on OS X, I'm afraid. But I plan to make the next version Mac compatible.

  • Like 3

Share this post


Link to post
Share on other sites

I've just tried the latest version with my ASI120MM and keep getting an error when I save the data. I've attached the error log.

James

Thanks for informing me James. I was able to replicate the error, and it's caused by a bug in the part of the code that adds the sensor data to a newly added camera profile.

I have uploaded a fixed version here. You only have to download it and replace the old .exe file.

Clear skies,

Lars

Share this post


Link to post
Share on other sites

I've written a quite comprehensive user guide to APLab version 0.2.0/0.2.1. It's available on the website.

Clear skies,

Lars  :smiley:

  • Like 1

Share this post


Link to post
Share on other sites

Still haven't got round to playing with this - but it seems flippin useful!

Have grabbed the new version and will give it a play ASAP.

Just a quick question on the saturated frame for the analyser - presumably this is a point source of light (not necessarily a star) that saturates a portion of the image - not a complete full frame saturation?

  • Like 1

Share this post


Link to post
Share on other sites

Still haven't got round to playing with this - but it seems flippin useful!

Have grabbed the new version and will give it a play ASAP.

Just a quick question on the saturated frame for the analyser - presumably this is a point source of light (not necessarily a star) that saturates a portion of the image - not a complete full frame saturation?

Yes, the program finds the max pixel value in the saturated frame to determine the white level, so it's enough that at least one pixel in the image is completely saturated. If you have added a frame in the light frame category you can choose to use that as the saturated frame when you press the button for calculating sensor data (since most light frames will have saturated pixels).

Share this post


Link to post
Share on other sites

Hi Lars

Doing some playing today:

When adding the two Bias frames, I got an error saying " the exposures were very different (0s vs 0s). Do you want to continue?"

When adding a file with an extra period in the name, the file does not load

Plus I got some Python errors when changing some of the drop down values, but I don't seem to have an error file..

I can send you my files if you would like them?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.