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Checking Your Calibration
Updated over a week ago

Explained

The calibration is used to tell the system the position & orientation of your cameras, so it can turn the 2D footage into 3D data when you process your motion capture action takes. When your calibration has finished processing, there are a few things you can check to determine the quality of it. The quality of your calibration will contribute to the quality of the motion capture, so it's always worth trying to get the best quality calibration.


Information

This window allows you to check the input settings you provided for the system to process the calibration.


Status

This provides a rating, ranging from Excellent to Very Good, Good, Weak & Poor. The rating is determined based on many factors, including the reprojection error. If your calibration is Weak or Poor, please refer to the Troubleshooting Section below.

This also provides a comment, to identify some common errors. Here's what they mean:

'Calibration is poor. One or more cameras have been skipped. Please check the following cameras [] before proceeding.'
  • If the data from some cameras doesn't agree with the others, they will be skipped. Try removing the respective cameras, by using the 'Create new from' button to duplicate your session with only the chosen cameras and process a new calibration. This could be because they couldn't see the actor clearly, or are a different model to other cameras.

'Cameras [] show bigger error than expected.
  • If the data from some cameras has a great pixel error when compared to other cameras, they may have negative impacts on the overall tracking. Try removing the respective cameras, by using the 'Create new from' button to duplicate your session with only the chosen cameras and process a new calibration. This could be because they couldn't see the actor clearly, or are a different model to other cameras.

'Calibration is poor. There is a mismatch in resolutions used and the camera type selected. Please check the following cameras [] before proceeding.'
  • In order to process the footage, all videos must be the same resolution and from the same camera model (unless using Experimental Mode).


Sync

This video contains the clip from the input videos between the first and last clap time. Use this video to visually check that the system has synchronized the footage correctly. Ignore this if timesync'd cameras were used.


Calibration Quality

This graphs shows the reprojection error when comparing the data from each possible pair of cameras. The colour scales from green (smallest) to red (largest) reprojection error. If there is no colour, it shows the pair was skipped, which will be outlined below the graph. It is normal for some pairs to be skipped, however, if some cameras are skipped consistently in all pairings, this indicates a major issue with the respective cameras. Try removing the them by using the 'Create new from' button to duplicate your session with only the chosen cameras and process a new calibration.


Camera layout

This 3D viewer allows you to see the recreation of your camera positions, with respect to the origin (where the actor began the Y-pose sequence). You can use this to visually check if the layout is as expected.


Download

Here you can download the JSON file of your camera positions.


Troubleshooting

If you achieved a weak or poor calibration, it's worth checking a few things to see if you can achieve a better calibration.

Check your input settings are correct:

  • Clap times (not necessary if footage is sync'd) - this window should contain all three claps.

    • Example - If you enter 00:03 - 00:06, it will use the audio from the entire 3rd, 4th, 5th and 6th second.

  • Y-pose sequence times - this window should begin when the actor is stood still in the Y-pose.

  • Actor height - this should be the height of the actor, excluding footwear.

You should also check your videos are:

  • Named correctly & consistently

  • The same duration (at least within 2sec difference)

  • The same resolution

  • The same framerate

  • Uploaded correctly and can be previewed when selected for your Calibration

  • Matching the Session Settings

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