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Author Topic: questions for marker.position and filter/classifications  (Read 48 times)

Phogi

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questions for marker.position and filter/classifications
« on: October 12, 2018, 08:59:23 AM »
Dear Alexey,

May I know what's the unit of marker.position? I searched some threads and know it's in camera plane, is it what is used for (X, Y, Z) - point coordinates in the local camera coordinate system? For a pixel in the camera, could you give an example on how it gets the position values? Also the u/v in camera calibration value would it be expected as millions or few handreds if it's pixels?

My another question is about the classification function, the angle/distance settings are clear, but could you offer some articles on how they are working? Cause sometimes I filter a conveyor and it removes the other points for different densities. Also if the automatic classification can add other classes other than ground?

Thanks a lot!

Alexey Pasumansky

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Re: questions for marker.position and filter/classifications
« Reply #1 on: October 13, 2018, 06:44:40 PM »
Hello Phogi,

The units are in the internal chunk's coordinate system (same as camera.center, region.center, for example). So what task you are trying to solve, which coordinates should be transformed where to?

The base principles of the ground points classification method applied in PhotoScan Pro 1.4 are described in the following scientific paper:
http://www.isprs.org/proceedings/Xxxiii/congress/part4/111_XXXIII-part4.pdf

In the version 1.5.0 there is another classification possibility that is based on machine learning, there the following classes can be automatically assigned: Building, High Vegetation, Ground, Road, Car, Man-made.

Best regards,
Alexey Pasumansky,
AgiSoft LLC