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Step 4 – Camera Calibration

• Click on the New Page icon .

• Enter 2D view and first physically remove all reflective objects, such as the calibration kit or similar reflective equipment, from the measurement volume.

  • Go to the Camera settings sidebar on the right side of the 2D view. Click on Enable for Marker masks.

  • Click on “Auto-create” and start. QTM will mask all unwanted reflections. For manual masking options and advanced handling of camera settings and marker masks, please refer to the QTM Manual.

    

• Place the L-shaped calibration reference on the floor.

  When using force plates, the placement depends on the convention that was used when setting up the force plates in QTM. We recommend that you take a picture of the default placement of the L-frame and put that picture in your lab. Precise alignment is critical for the calculation of the joint moments/power.

  Note the coordinate system must be set up so that the global x-axis is pointing towards the target:

  

• To calibrate, click on the calibration tool on the top menu bar.

  

• A window will open that will ask how long you would like to capture. 20-30 seconds is a sufficient amount of time for a standard full body volume. For large volumes, increase the time so that you have enough time to cover the complete volume that will be used.
• Click start and you will hear a bell. Using your calibration wand walk around the capture area and wave the wand in the area that the subject will be moving in. Note: for guidance how to move wand in the volume refer to QTM user manual in the section Making a measurement > Calibration of the camera system > Wand calibration method.
• Stop when you hear another bell.
• Confirm that the average camera residual is approximately 1-2 mm or under. Each camera should have collected at least 300 points. The standard deviation of the wand length should be 1-2 mm or better for a full body volume.

• If you use the C-Motion Caltester, now you can perform a test to ensure the L-frame was aligned correctly and the force platform settings are correct.