Capturing with multiple video systems for markerless tracking

The Miqus video cameras must be split in multiple systems when there are more video cameras than the computer model can handle. For example, a computer with the 11th generation of Intel I9 processor, a maximum of 24 cameras can be used at full speed and resolution. A computer with the 10th generation of Intel I9 processor can handle up to 16 video cameras.

The setup for multiple video systems are described in How to set up multiple video systems. The system will consist of one Main system with the Camera Sync Unit and Agent systems which are time synchronized with the Main system.

Calibration

First of all the camera systems must be calibrated in one calibration file so that the video can be processed in Theia. Follow these steps to calibrate the system:

  1. Disable the blocklist in QDS on the Main system.

  2. Restart the cameras on the Agent systems and shutdown QDS before they receive the IP address from the Agent system. The cameras will now get an IP address from the Main system.

  3. Calibrate the system with all video cameras, for general advice on calibration of video cameras, see chapter Calibrating Qualisys video cameras.

  4. Enable the blocklist in QDS on the Main system.

  5. Start QDS on the Agent systems.

  6. Restart all cameras, so that they get the IP address from the correct system.

Setting up synchronization

When the system is calibrated follow these steps to capture synchronized video in all of the systems.

  1. Start the capture on all of the Agent systems so that QTM is in the Waiting for trigger mode. The cameras are waiting for the UPD packet with the camera start time from the Main system, for configuration see chapter How to set up multiple video systems.

  2. Start the capture on the Main system. The Main system will trigger the Agent systems via the UDP packet so that the video capture starts at the exact same time.

  3. Once the capture is finished the QTM and video files are saved on each separate computer. The UDP packet includes the file name used on the Main system so that the QTM and video files on the Agent systems automatically use the same name.

Processing with Theia 3D markerless mocap software

After the video capture follow these steps to process in Theia.

  1. Copy the calibration file from the Main system to the computer with Theia.

    The computer with Theia can be the same as the Main system computer, but it is not possible to process in Theia at the same time as the computer is capturing video files.

  2. Copy all of the video files for one capture from Main and Agent systems to a new folder on the computer with Theia. It is important that the folder only includes the videos from one capture for the Theia processing to work.

  3. Optionally copy the QTM files to the same folder as the video files. The QTM files are not needed for the Theia processing, but are good to save to be able to read the settings used for the capture. It is important to rename the QTM files from the Agent systems since otherwise the files all have the same name.

  4. Start Theia and import the video files and calibration manually. Please refer to the Theia manual for instructions how to perform the processing.

    Theia will rename and move the video files, so you need to have a copy of the video files if you want to be able to open the QTM file with videos.