How to Identify misaligned images?

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    Wishgranter
    Hi julesmalcomson

    Can you provide us with some screenshots ?
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    julesmalcomson
    Image
    Image
    Image
    These were rendered at normal quality.
    When I rendered the same model on high these artefacts were gone, which suggests I was wrong in thinking it was a misaligned image.
    Any ideas what causes this? The patterns didn't seem to correspond to the model chunks which is what led me to think it was a bad camera causing the problem.
    All settings were on default for this.
    Thanks
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    julesmalcomson
    Any ideas what causes this? I know this can generally be avoided with more photos but I'm still curious to know what causes this, it will add to my understanding of how RC works
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    ssh4
    Not a experienced CR user, but if i have similar issue in other tools, this usually happen if such place have more detailed shots than surrounding areas. For example area around shoot far from object, but this area shoot from small distance. And this is probably depend on sharpness and details of this images. Also this areas have more dense polygon count.
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    Wishgranter
    Hi julesmalcomson
    If all images are SHARP, then it is a problem of misalignment of a few images, as RC is calculating and weighing depth maps, so if you get this on NORMAL, then it can be suppressed on HIGH as there is 4 times more data for the final mesh calculation and they can overweigh the trouble-making images-depth maps.
    How to identify misalignment ? It depends on a scene, but sometimes it can be really problematic ( depending on too many factors ) - in this case is good to do the alignment in parts. Is it a big dataset or just small one ?
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    julesmalcomson
    It's only about 300 images. The object was very glossy so I had to 'texture' it using developer spray. The model features down to to sup pixel level and every image was pin sharp at 36mp, but the object was definitely not ideal for photogrammetry.
    Do you mean that I should run alignment in chunks of around 5, and then use control points to align manually align the components?
    Is this to help me identify the bad images? or does it just help RC if the cameras are aligned in smaller groups?
    Thanks

    Jules
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    Wishgranter
    Hi Julesmalcomson
    So the culprit of the missalignments is found :D

    Is it possible for you to put newspaper under the scanned subject ? Powder is a good solution, but the drawback is that it can create repetitive patterns and so you can get to missalignments..
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