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localdevices / pyorc

Surface velocity, object tracking, and river flow measurements in an open-source API
GNU Affero General Public License v3.0
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Using lens_position without crs #160

Closed Andreas-Bombaert closed 5 months ago

Andreas-Bombaert commented 5 months ago

How did you install pyopenrivercam (mamba / conda or pip)

conda

What is the problem?

For my master thesis at UCL we are building an UI using pyorc to process the riverflow, but in our case we don't have the crs for the camera config and we have to use the lens_position, which are [x, y, z] coordinates following the documentation. My question is: from where do these coordinates start? I don't know if it is from the top-left corner of our beacons, or the center of the beacons?

It seems that I do not have the right lens position since pyorc does not find any velocimetry on my video. I managed to make it work on an other video but when I plot the transect I have inconsistent results.

In the first use notebook I see that for the VGC example the lens_position is set at [7, -2, 3] but from where the X and Y begin?

Thank you for your time, Andréas

hcwinsemius commented 5 months ago

The lens position should be measured in the same coordinate system as all other coordinates. For instance, if you use a GNSS RTK device, you can use the closest UTM system. But you can also use a spirit level or a distometer and measure all coordinates in your own local coordinate system.

Please check out https://localdevices.github.io/pyorc/user-guide/camera_config/index.html#measuring-the-gcp-information for instructions and diagrams. This should explain it quite well.

Please let us know if you have further questions, or if we can close the issue.

Andreas-Bombaert commented 5 months ago

Ok, thanks for the quick answer! You can close the issue.

hcwinsemius commented 5 months ago

Thanks! Let us know if you have further questions.