Recording a Video for Motion Capture

Overview

Motion capture technology is the process or technique of digitally recording patterns of movement. The Industrial Ergonomics job improvement process uses motion capture to analyze and assess human body postures in a video without the use of sensors or markers.

To ensure your job assessment is accurate, it is critical to collect good video data for motion capture processing.

For more about the types of jobs and environments best suited for motion capture, see What are the benefits and limitations of motion capture?

Best Practices When Filming for Motion Capture

• • Use a handheld device, such as a tablet or a mobile phone.
  • Choose an experienced operator for your video who is familiar with the job.
  • Ask permission from the operator, so that they are prepared and can be filmed safely. Be sure to mention the privacy options of blocking the face and/or blurring the video, if applicable. For more about privacy with motion capture, see How private are motion capture videos?
  • Include only one operator in the frame. Multiple operators in the same recording can skew results.
  • The operator should perform the job as it is normally done. Try not to ask the operator questions during the video, nor have the operator explain what they are doing while recording. Instead, get an explanation of the task steps prior to recording.
  • Limit unbuttoned or unzipped outer garments. Zip, button, or remove loose clothing to obtain more accurate results, when possible.
  • Record from the side that best represents the risk, when feasible, to obtain the most accurate data possible. 
  • Include all body segments being evaluated in the frame.
    • Follow the operator with the camera. If the operator moves around, move with them to ensure they remain in the frame at all times.
    • Avoid recording in environments with poor lighting or reflections.
    • Make sure that the operator’s clothing does not blend into the background.
    • For most jobs, use a vertical camera orientation when possible. However, for seated jobs with lots of arm movement, use a horizontal camera orientation.
  • Ensure arms, ears, and the nose are visible to detect the most accurate angles.
  • Calibration is not required. There is no need to have the operator pause at the beginning of the video.
  • Avoid abrupt camera movements. Handheld tripods can help keep the camera steady.
  • Record one non-stop video between 30 seconds and 2 minutes long. The optimal length for a video is around 30 seconds. Videos under 10 seconds long may not produce accurate results.

Uploading Your Video

There are several different ways you can upload your video for motion capture processing.

Do:

• • Upload directly from your device
  • Upload to a shared drive or airdrop
  • Upload to a computer via a file transfer cable

If you can maintain a good internet connection from your mobile device or tablet, we recommend you load the video directly from your device to the application, if possible. Otherwise, you can upload it first to a computer, then to the application.

Do not upload your video by:

• • Emailing the video
  • Recording it from within your Industrial Ergonomics site

Make sure your video is either an .MOV or .MP4 file that meets the following requirements:

• • Minimum resolution 720p (1280×720)
  • Maximum resolution 4K/UHD (ultra high definition, 3840×2160)
  • Under 500MB

To avoid potential challenges with the file:

• • Avoid special characters, symbols, or punctuation in the file name.
  • Do not convert .MOV files to .MP4 and vice versa. Handbrake is a free download that can assist you with file format conversions.
  • Trim the video prior to upload, if longer than 5 minutes.