About laser scan reference

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geoanture86

Hi friends, 

i have some component

1 of photogrammetry via Sony

1 of drone

1 of laser scanner

 

i would like to merge the component but i want a laser scanner component like a reference..

 

thanks

 

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    Ondrej Trhan CR

    It is not problem with locked pose. It depends, how your project and output coordinate system is set in Application settings and how the laser scans were imported into RealityCapture.

    What do you mean by original point cloud?

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    geoanture86

    What do you mean by original point cloud?

    -the point cloud alligned in another software

     

    I cechked and the project was wgs, now i put in local1

     

    and i have to export in grid plane? or xmp? what is xmp?

     

    thanks

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    Ondrej Trhan CR

    If it is not georeferenced, then there could be differences between different softs, as the origin can be set differently.

    It depends, what you want to export. Both are internal RealityCapture's coordinate systems (grid plane you can see in 3D view)

    XMP system is slightly different to a grid plane, it is related with cameras. RealityCapture defines a series of XML tags which naturally extend the Extended metadata format (XMP) with information like camera pose, orientation, calibration information, priors and more. Vice versa, providing these data, the application can read them and use them as constraints for geo-referencing - or more precisely - fixing the coordinate system.

    XMPs allow setting a camera pose directly and thus define the coordinate system:

    • define the camera position,
    • define the camera position and orientation,
    • define the relative or absolute position of cameras.

    This opens a way for industrial business cases where the same camera setup is used over and over again and you want to ensure that the resulting scan will stay in the same coordinates.

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    geoanture86

    Ah ok. thanks for information..

     

    but i have tested with a both oprions in local1 and the model was shifted..

     

    i don't know why

     

    if i use a cloud compare for allign in to my local system (pointcloud original allignemnt coordinate) the model generate, and i copy the rototraslation matrix, can i import in reality? or copy the parameters?

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    Ondrej Trhan CR

    Yes, you can use these parameters in export mesh settings:

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    geoanture86

    and you know how?

    this is a matrix of cloudcompare

     

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    Ondrej Trhan CR

    This part is rotation matrix, you need to compute rotation angles form it. It is possible to do here: https://www.andre-gaschler.com/rotationconverter/

    But CC could have different axis (where they are pointing) than RC, so you will need to find the right rotations.

    This part should be translation in the axis

    Or you can try to export some point from your original model, use them as GCPs in RealityCapture and update the model to this points. Then the models should be in the same coordinate system

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    geoanture86

     

    This is a CC replay

     

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    geoanture86

    im solved..

    cechk the image

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    geoanture86

    And i have solved the allign problem, now the model are perfect.. thanks..

     

    but there is a problem with a model coordinate... i don't know why

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    geoanture86

    The last question..  i had generated an ortophoto but when i export and import in a cad software which is the correct scale?

    how i reconpute a correct dimension?

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    Ondrej Trhan CR

    The scale should be correct as you used the laser scan as reference, which is in meters

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    geoanture86

    Yes, and for do this, i have to put laser scanner position locked, right?

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    Ondrej Trhan CR

    Don't have to. But then this should keep the original coordinate system and the alignment is not changed

    • No changes in camera position and orientation allowed during alignment
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    geoanture86

    ok...

    and how i calculate the ortophoto real scale?

    i have a facade the model are correct but the ortophoto is scaled, how i re-scale in a correct dimension?

     

    thanks

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    Ondrej Trhan CR

    Ortho should be in the size of the model, so it should be scaled correctly.

    What are your settings there?

    Is the TFW file created also with ortho?

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    geoanture86

    i have this 

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    Ondrej Trhan CR

    So, it is created with tfw file (in your case jgw, as you exported jpg).

    TFW file created from side view, Projected:
    -0.0000000000                 - rotation
    0.1438256053                  - X pixel resolution
    0.1439776282                  - Y pixel resolution
    0.0000000000                  - rotation
    -128.9205612660             - X coordinate of upper right image corner
    -1350524.4813268578     - Y coordinate of upper right image corner
     
    To use the file in CAD, you should transform it into this format:
    0.1438256053                  - X pixel resolution
    0.0000000000                  - rotation
    0.0000000000                  - rotation
    -0.1439776282                - Y pixel resolution 
    -1350524.4813268578    - X coordinate of upper right image corner
    128.9205650291             - Y coordinate of upper right image corner
     
    Do you need 5 mm ortho resolution? Is the building approximately 8 m high? 
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    geoanture86

    Yes 5mm and around 8 meters..why?

    but i cad where i put? 

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    Ondrej Trhan CR

    If the building is 8 m high, then it is scaled good (there is -8 m in your jgw file)

    This file could be apply automatically in some software, but in AutoCAD you need to have installed plugin: https://www.cadstudio.cz/georefimg for example.

    But you need to change the file according the example from previous message (change the lines)

     

     

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    geoanture86

    Wooooow.. you have solved all my problem...

    fantastic..

    thanks a lot

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    Ondrej Trhan CR

    You're welcome

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    geoanture86

    Ondrei, how are you?

    before i delete photoscan, i have another question.

    it is possible to merge 2 component using a know control point?

    i have a bad overlap beetwen laser and drone photo.. but i have a know coordinate of cp..

    can i rototranslate and scale a component drone via cp with a know coordinate of control point?

    you andestrand?

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    geoanture86

    this is my question and my problem..

    in the first image i have a point cloud in my software and are display a reference point in a localsystem.

     

    i exported a point and point cloud and i imported in RC, but the result was different..why?

    RC change the coordinate system

     

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    Ondrej Trhan CR

    What were your laser scan import settings? Did you choose the right coordinate system?

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    geoanture86

    I choose, local coordinate 

     

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    Ondrej Trhan CR

    So it was like this:

    The GCPs have the same coordinate system? Are the scans in local coordinate system? Maybe don't use Locked in this case.

    About your previous questions, it is possible to merge laser scans and images using control points. You just need to find these point on images and place them there. Then just realign project.

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    geoanture86

    i have to put the cgp in the photo and laser, alright?

    yes i used this, exact.. yes is the same system coordinate..

    this is a reason because the last project when i exported the model was shifted..you remember?

     

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    Ondrej Trhan CR

    i have to put the cgp in the photo and laser, alright? - Yes, if you want to merge your datasets

    this is a reason because the last project when i exported the model was shifted..you remember? - I remember, but this shouldn't be the reason for movement. Is it possible to share your data with us?

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    geoanture86

    yes.. i send the link, but the upload is slowly.. 1 or 2 h

    https://1drv.ms/u/s!AqWlY7FMvK9yjsNxhspaaHVC33E26A?e=lPEHdd

     

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