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Small objects scanning

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3 comments

  • MartyG

    Hi Payman Azari  Creating 3D point cloud scans of small body parts such as nose, ears and mouth is achievable with a RealSense D435 or D435i camera model, though it requires some small adjustment of settings, such as using a Disparity Shift value of '50' so that the minimum depth sensing distance of the camera is reduced.  This allows the camera to get closer to a surface than the default minimum distance of 0.1 meters / 10 cm on the D435 / D435i models.

     

    Below is an image of a point cloud scan of my ear that I took with a D435i camera set at a Disparity Shift value of '50' and the Hole-Filling post-processing filter enabled to greatly assist in closing up black holes.

     

     

    If the built-in RGB sensor of the D435i camera cannot meet your color resolution requirements then it is possible to sync an external HD RGB camera with depth data of a RealSense camera.

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  • Payman Azari

    Hi MartyG , Thanks for your very helpful tip. Can you also tell me, in this situation how much would be the depth resolution of the  image in millimeters? (with Disparity shift = 50)

    Gratefully,

    Payman. 

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  • MartyX Grover

    In the above test, 848x480 depth and 1280x720 color was used.  On the D435 and D435i models, you can use 1280x720 for depth but 848x480 is the optimal depth accuracy resolution.

    Using a Disparity Shift enables the camera to get closer to an object / surface before the depth image starts breaking up below the minimum distance.  It has the trade-off that the maximum observable depth sensing distance is also reduced as the Disparity Shift value is increased.  This isn't so much of a problem when performing close-range sensing though, and '50' is a good all-round value that enables the camera to get closer whilst also preserving further away detail on the image (such as the front of the head in the image above).  

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