Creating a seamless Mosaic

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  • #13283

    Haverkamp
    Participant
    posts: 648

    Hi all,

    In this topic I’ll discuss the steps which you need to make to make a seamless mosaic in APP. And I am working on a video tutorial as well. But i’ll start with a quick explanation on how to do this in APP.

    Update: first instructional video is online at my astro pixel processor vimeo website:

    https://vimeo.com/astropixelprocessor

    – First, to get the best results, it’s always best to correct your mosaic panels for gradients as good as you possibly can using the remove light pollution tool.

    – Next step is to load your your mosaic panels as lights into APP. For even very complicated situations , you don’t need to alter anything in 3) Analyse Stars.

    – The (multiple view) mosaic registration is selected in 4) Register

    – enable “dynamic distortion correction”, because unless your data is already perfectly rectilinear, you will need this to get the best registration.

    – To make your first mosaic, deselect “same camera and optics”. This selectbox is here for a reason, but needs some explanation which I’ll do later. For now deselecting this is just fine.

    -Registration mode, choose “mosaic”

    -Leave the model at projective, calibrated projective is needed if your field of view is bigger than 120 degrees.

    And start registration. APP will now try to find the best registration hypothesis between all 2-view registrations that are possible. Once all 2-view registrations are done ( for a 10 panel mosaic, it will need to do 1+2+3+4+5+6+7+8+9 = 45 two view registrations) APP will then calculate a multiple view registration hypothesis and tries to find distortion correction parameters for all frames, including the reference frame. By treating this as one single problem, APP can solve this problem in one go. You don’t need to register frame by frame against a reference yourself. Another advantage of treating this as one problem is that you will have much more certainty that the solution that APP finds is the most optimal one for all frames in your mosaic.

    After registration, you’ll get feedback about the registration RMS in the file details window. Check that all frames of your mosaic were registered and have acceptable RMS errors ( well below 1 pixel is what you are looking for)

    Proceed to 5) Normalize

    use defaults or at your next attempt, try mode advanced. Depending on the arrangement of your mosaic panels, this can make a difference in how well the mosaic comes out in the end.

    Then 6) Integrate

    choose composition mode FULL and click on the apply button ( the apply button is there for creating a crop in the reference to stack to, usefull to immediately drizzle small object in your field of view for instance)

    Then to get the seamless mosaic, enable Local Normalization Correction

    you can choose the degree and iterations. In most cases, a fourth degree LNC with 3 iterations will already give you a very good result. IF not, increase the degree and possible iterations.

    And enable multi band blending, the percentage is a percentage of the image dimensions of each panel that is registered into the mosaic. So the percentage is relative and so in absolute terms will differ if you combine panels of different sizes in the mosaic.

    Enable normalization and weight maps, these will show you how well the panels were integrated and could give you clues if you are having problems in getting a good result.

    If you are creating a huge mosaic ( bigger than 10000 x 10000 pixels) start of with making the mosaic on a smaller scale

    at pixel interpolation select no under/overshoot

    At integrate choose scale 0,3-0.5 to start with.

    If you like the result you can increase the scale in the next run 😉

    Please share your results, good or bad, possibly I can help in improving it…

    #13284

    MauriceToet
    Participant
    posts: 52

    Thank you very much, Mabula. This worked excellent! (See attachments.)

    Request for change: I think most users would appreciate if you set the “number of lights to stack” at 100% by default. In this particular case, I had two panels to align, and the program only selected one by default.

    • 1 person likes this.
    #13288

    Theunissen
    Keymaster
    posts: 1037

    See attachments

    Hoi Maurice, klik eens op het blauwe camera symbooltje voor de aardigheid 🙂 rechtsonder het invoerveld i.p.v Attachments (No Photos) bij het uploaden van images.

    #13292

    MauriceToet
    Participant
    posts: 52

    Hoi Maurice, klik eens op het blauwe camera symbooltje voor de aardigheid rechtsonder het invoerveld i.p.v Attachments (No Photos) bij het uploaden van images.

    Aha, dat ziet er beter uit 😉 Al die keren over “No Photos” heen gelezen… Doorgaans upload ik foto’s op mijn eigen website waarnaar ik vervolgens hotlink.

    #13293

    Theunissen
    Keymaster
    posts: 1037

    Had ik de “No Photos” nog zo’n mooi kleurtje gegeven 🙂 . Ik zie overigens dat op AF precies hetzelfde gebeurt, alleen dan veelal met dubbel uploads als gevolg @norbert.

    #13294

    Haverkamp
    Participant
    posts: 648

    Excellent ! Looks very good, beautiful field of view in the Barnard region 😉

    RFC noted, it’s already fixed in the latest version 😉 which I uploaded today. (And I am uploading a new version again…)

    #13297

    Haverkamp
    Participant
    posts: 648

    Hi Maurice,

    I see you did 8 iterations of 1st degree LNC + MBB 5% and you already got this good a result.

    In complicated situations, for instance with more panels, the higher degree LNC is very valuable.

    In the fits header of the stack, you can find the details of the LNC proces, the normalization map has some statistics as well 😉

    #13300

    MauriceToet
    Participant
    posts: 52

    And here’s the post-processed (in Photoshop CC) result.

    1h35 minutes of exposure time for the M78 pane, 2h of exposure time for the LDN 1622 pane. Exposed with a Baader modded Canon 5D MKIII @ ISO 1600 (5 min. subs) and Takahashi Epsilon-180ED. 25 February 2017, Étoile-Saint-Cyrice (France).

    • 6 people like this.
    #13304

    Haverkamp
    Participant
    posts: 648

    This is a phenomenal picture @mauricetoet 😉 ! Simply stunning…

    • 1 person likes this.
    #13311

    Musquetier
    Participant
    posts: 455

    Waanzinnig mooi Maurice!!!

    • 2 people like this.
    #13314

    KeesScherer
    Participant
    posts: 1396

    And here’s the post-processed (in Photoshop CC) result.

    Fantastisch @Mauricetoet , mijn complimenten!  Weer een nieuwe referentie.

    • 2 people like this.
    #13315

    Theunissen
    Keymaster
    posts: 1037

    Prachtig inderdaad, en een mooie referentie voor APP!

    • 2 people like this.
    #13322

    Groenewold
    Moderator
    posts: 1158

    Pfffff, geweldig! Niks op aan te merken gewoon en inderdaad indrukwekkend hoe APP zorgt voor het gemak van naadloos stacken. Volgende keer dus mijn spullen mee naar zuid-Frankrijk. 🙂

    • 2 people like this.
    #13360

    MauriceToet
    Participant
    posts: 52

    @bula, @musquetier, @keesscherer en @supernov: bedankt voor jullie complimenten. Mede mogelijk gemaakt door APP 😉

    • 2 people like this.
    #13513

    Rosen
    Participant
    posts: 16

    No kidding – that’s a great mosaic, Maurice!  Congratulations to both you and Mabula!

    • 1 person likes this.
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