Mavic 2 Pro in Sensor Data

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    Erik Kubiňan CR

    Hello dear user,

    The sensor width of Mavic 2 pro should be "13.2" 

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    Parker Hill

    Hello i.moreno,

    One problem with using the Mavic 2 Pro is that it has a rolling shutter. A rolling shutter can cause issues of distorting and is not well suited for photogrammetry purposes. The rolling shutter effect becomes significant when flying the drone fast and or when flying at low altitudes.

    I would recommend using the DJI Phantom 4 Pro because it has a mechanical shutter, and it is back on the market because of the demand for a drone with a mechanical shutter.

     

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    i.moreno

    i understand the differences but the Mavic 2 pro has a better camera and takes better images - other photogrammetry apps support it directly in their database to address the rolling shutter issues since its the top drone on the market.

    are there any plans to add it to the reality capture sensor database ? it would help with processing images and alignment issues etc for sure and i am sure its not hard to do if you know how to do it...

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    Erik Kubiňan CR

    I will move this request further. For now you can add

    <camera model="DJI L1D-20c" ccdWidth="13.2"/>

    To the sensorsdb located in C:\ProgramData\Capturing Reality\RealityCapture 
    That should do the job until we add it in.
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    i.moreno

    Thanks Erik!

    <camera model="Canon EOS REBEL T3i" ccdWidth="22.3"/>
    <camera model="DJI L1D-20c" ccdWidth="13.2"/>
    <camera model="EASTMAN KODAK COMPANY KODAK EASYSHARE M575 Digital Camera" ccdWidth="6.17"/>

    We have added it to the sensor db but our projects still show up with the yellow triangle - do we need to re-import the images ?

     

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    Erik Kubiňan CR

    Please try to, on a clean project so you don't have to change this one. Test a few of the DJI ones.

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    Steven Caron

    I would really like to understand what CR devs advise when it comes to the DJI Mavic 2 Pro's built in lens profile? If you shoot JPG, it will be baked in. If you shoot RAW (you're shooting RAW right?) you have an embedded profile which Adobe products will bake into the image you output for processing in RC. For instance, DNG->Lightroom->tiff->RC. The embedded profile corrects distortion and crops the image, doesn't this introduce error? So if DJI Mavic 2 Pro is to be supported by RC, what image workflow is supported?

    I have been stripping the profile before going into Lightroom, then doing color calibration in Lightroom, and exporting 8bit images for RC to process. I typically find about 3-4% reduction in error compared to profile being baked in. 

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    Erik Kubiňan CR

    Dear Steven,
    The inputs can be in any of the supported formats, but I recommend you to shoot RAW decrease highlights, raise shadows, adjust the exposure and export JPGs into RC without doing the lens correction outside of RC, it is best to let RC do it when it has the profile information.

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    Steven Caron

    Thanks for replying Erik... I am well aware of the issues doing lens correction outside of RC and I thought I made that clear in my post, so that makes me wonder if you understood my above post. Let me try again... The images from the Mavic 2 Pro already have lens correction on them!

    If you shoot JPGs with the Mavic 2 Pro and bring them into RC, the image will be undistorted (lens correction) and cropped.

    If you shoot DNGs (RAW) with the Mavic 2 Pro and load these into Lightroom or Photoshop through CameraRaw you will get the the same undistorted (lens correction) and cropped image.

    Both scenarios are NOT best for RC! This is why I have been stripping the metadata of the DNG files to remove the embedded lens correction profile. Then doing processing in Lightroom and exporting to RC. I have found about a 3-4% reduction in median and mean error rates. This may not be a lot but it is consistent reduction of error for me when I remove the embedded lens correction.

    What do the developers think about this? You can't just put in a ccdWidth of 13.2 mm in the sensor database if the image is being heavily manipulated by default. Even if you guys are suggesting to shoot RAW and do only color processing you STILL get a lens corrected image out of Adobe products.

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    Erik Kubiňan CR

    Oh okay Steven, thank you for clarifying this to me. That is very odd but I will surely communicate this with my colleagues, Thanks again for providing us with such information.

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    Steven Caron

    Hello Erik, Thanks for the follow up!

    Please let me know if there is any information I can provide to help with this. Or maybe I don't understand how RC internals work that make this a non-issue? I am hoping at the very least there is just an official word from RC Devs on how to handle Mavic 2 Pro data (or any DNG with an embedded profile) to minimize error.

     

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    Steven Caron

    Hello Erik, Does the development team need any more info or data on this subject? Here is an example of the crop and undistort that happens with the embedded profile.

     

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