Vicon Blue Trident banner

To start Capture.U and choose the way in which you want to capture data:

  1. On your iOS device, start Capture.U.

    If you need to upgrade the firmware for your Blue Trident sensors, when you start Capture.U the sensors are displayed with a yellow warning symbol, and a message alerts you to their status:



    Click Get Desktop App to directly open Capture.U Desktop, or click OK to close the message, and upgrade the sensor firmware with Capture.U Desktop (see Update sensor firmware).
  2. Tap to choose a capture mode.

Your choice of capture mode depends on the number of sensors you want to use, the range you require and the type of output you want:

  • For unlimited range and up to 20 sensors, with reference video data directly from the device, choose To Sensor. After you have captured the data, download it to your computer with Capture.U Desktop for further analysis.
  • For data that is saved directly to your device (where the capture range is constrained by the Bluetooth® range of the device), choose To Device or Real-Time Insight mode.
  • For access to Apple’s ARKit video-based visualization (the iOS device must be compatible with Apple ARKit 3), choose AR Visualization mode.

In all capture modes, there may be a lag in data frames (a small offset) between sensors when starting capture, but the data will be synced. 


The capture modes are explained in more detail in the following sections:

If you plan to capture global angles, after the sensors are attached to a subject, allow a few seconds for onboard calibration to initiate before starting the movement that is to be captured.

Capture to sensor

Choose the To Sensor mode when you want a high sensor count and unlimited range. After capturing the required movement, you can download your data with Vicon Capture.U Desktop.

An example of this type of usage might be to monitor the track performance of multiple athletes who are running a marathon. After capturing data from all the athletes, you can download the data from the sensors to your computer with Capture.U Desktop (see Use Vicon Capture.U Desktop).

Watch the Vicon video, Capture to Sensor on YouTube.

Summary of To sensor mode:

No. of sensors:Up to 20
Data type:IMU data
Video:Reference video
Axes:15
High G and Low G accelerometer
Gyroscope and Magnetometer
(option to capture all axes)
Global Angles
Output:Data (.csv, with Desktop)
Video (.mp4) and notes (.txt)
Range:Unlimited
Capture rate:

High G accelerometer (default): 1600 Hz
Low G accelerometer and Gyroscope: 1125 Hz
Low G Magnetometer: 112 Hz
Global Angles (with Low G accelerometer, Gyroscope, Magnetometer): 225 Hz (A, G) and 70 Hz (M)

To capture to sensors:

  1. Open the Capture.U app.
  2. In the Capture section tap To Sensor.
  3. Either create a new session or select an existing one:
    • To create a new session:
      1. At the top of the screen, tap the plus sign + to the right of Sessions.



      2. In the Session Name field, enter a name for your new session.
      3. If you want to add an image as an identifier for the session, tap Take Photo and add the required image.
      4. Tap Done.
        Your new session is displayed in the list of sessions on the left.
        (To make any changes, slide the session towards the left and tap Edit.)
    • To select an existing session:
      • Tap an existing session in the list on the left.



  4. At the bottom, tap New Trial, then if required, enter a name for your trial. By default, the trial name is the same as the session name unless you rename the trial. Subsequent trial names are followed by a hyphen and a digit (for example,  MyTrial-1) and are automatically incremented (for example, MyTrial-2).

  5. From the options below, select the data to stream (Accelerometer ( High G or Low G ), Gyroscope, Magnetometer, Global Angles), and whether you want to capture a video. Note that if you select Global Angles, then Low G Accelerometer, Gyroscope, and Magnetometer are also captured and the capture rate is reduced to 225 Hz (A, G) and 70 Hz (M).

     

    If you plan to capture global angles, before you start capture, you must calibrate the IMU sensors. For instructions on how to do this, tap the How to calibrate link or see Calibrate IMUs.

    If you turn on Capture Video, you can choose to record High (1920 x 1080), Medium (480 x 360, the default), or Low quality (192 x 144) video.

  6. When you have made your selections, check below on the screen, to make sure the data mode is correct (in this case, it is Data captured to sensor), and tap Start Capture at the bottom of the screen.



  7. Select the sensors, by doing one of the following:
    • Tap to select the required sensors from the list on the right.
      or
    • Tap Enable Tap to Select and then tap the required sensor(s) twice.
      or
    • At the top of the list on the right, in the Search field, enter the number of the required sensor.



    If one or more of the sensors is displayed in orange and is labeled Reset required, see Reset IMU sensors.
    If you chose to capture Global Angles, one or more of the sensors may be displayed with a 'Require calibration' icon or a 'Calibrated' icon   at its top right. For further explanation, see the next step.

  8. At the bottom, tap Start Capture.
    If you chose to record a video, it is displayed at the bottom left of the screen.
    If Video is not selected, you can capture two trials simultaneously.
    To add notes during capture, tap Notes (top right).
    To add a region of interest, tap Start a region of interest at the top of the screen. For more details, see Work with regions of interest.

    If you chose to capture Global Angles: 
    1. If one or more of the selected sensors is displayed with a 'Require calibration' icon at the top right, after you tap Start Capture, on the next screen, a message at the the bottom of the screen prompts you to begin calibration when the trial starts. 

       

      After several seconds, the capture pane is displayed. A message towards the top of the screen prompts you to calibrate. 



    2. For more information on calibration, tap the How to calibrate link or see Calibrate IMUs.

    3. When you've finished moving the sensor, after 60 seconds the sensor icon changes to 'Calibrated' to indicate that calibration is occurring (calibration is a continuous process).
  9. When you have captured the required data, tap Stop Capture.
    Your new trial is displayed in the list of trials on the right of the screen, with the most recent trial at the top.



    If you recorded a video, you can play it back on your iOS device without exiting Capture.U by tapping the video icon on the right.

     

    To add notes after you have finished capturing, slide the trial towards the left and then tap Notes.



  10. To export any video and/or notes that you created, slide the trial towards the left, and then tap Export.

    As long as the sensors remain within Bluetooth range, you can add notes after you finish capturing a trial. These notes are saved to the sensor and, together with any notes made during capture, are available for review and export in Capture.U Desktop. For details, see Export notes from To Sensor mode.

    If you recorded a video, you are asked if you want to include it in the export. Tap Yes, then select the required export option.
    A .zip file with the name of your trial, which contains any notes (.txt) and video (.mp4) is exported.

    Use Quicktime or another suitable video player, eg VLC Media Player, to view the downloaded video file.
  11. Download your trial data (.csv) with Capture.U Desktop (see Use Vicon Capture.U Desktop).

Work with regions of interest

You can define regions of interest during capture in both To Sensor and To Device capture modes.

To define regions of interest:

  1. In a new or existing session, create a new trial and start a capture.
  2. To add a region of interest, tap Start a region of interest.



  3. At the top of the screen, in the Please enter a new region name box, enter a name for the region of interest.



    The name of the region of interest is displayed at the top of the screen. In the following example, it's named Stationary.



    The name of the region of interest name flashes to indicate that the data is being associated with the region name.

  4. To stop the region of interest, tap Stop the region of interest.



    When the region of interested is stopped, the region name no longer flashes.
  5. If required, you can now create a new region of interest.
  6. When you have defined the required region(s) of interest, stop the capture.

Regions of interest are saved, so you can select the newly created region of interest for subsequent trials. 

You can add add a region of interest's name to the Favourites list for easy selection in future. To do this, select the star icon next to the region of interest's name.

Export regions of interest

To export regions of interest from one or more sensors:

To export regions of interest from a device:

Capture to device

Choose the To Device mode when you need a higher sensor count than Real-Time Insight mode (which is restricted to two sensors).
Data is captured within the Bluetooth range of the device only. In this mode, you can also use reference video.

Note that as data is streamed over Bluetooth, external factors can cause dropped samples. If this is an issue, you can either interpolate between samples or use To Sensor mode instead, to avoid dropped samples altogether.

Watch the Vicon video, Capture to Device on YouTube.


Summary of To device mode:

No. of sensors:Up to 14 (depending on device, eg, BLE 4.2 iOS devices are limited to 7 sensors)
Data type:IMU data
Video:Reference video
Axes:3 or 12 
High G Accelerometer or
Low G Accelerometer, Gyroscope, Magnetometer and Global Angles
Output:Data (.csv), video (.mp4) and notes (.txt)
Range:Bluetooth: 20 m+
Capture rate:

High G accelerometer (default): 800 Hz 
Low G Accelerometer: 800 Hz
2-axes: Low G and Gyroscope: 500 Hz
Low G, Gyroscope 250 Hz and Magnetometer: 112 Hz
Magnetometer only: 112 Hz
Global Angles (with Low G Accelerometer, Gyroscope, Magnetometer): 225 Hz (A, G) and 70 Hz (M)

To capture to a device:

  1. Open the Capture.U app.
  2. In the Capture section tap To Device.
  3. Add a new Session or select an existing one (see Capture to sensor, Step 3).

    If you plan to capture global angles, before you start capture, you must calibrate the IMU sensors. For instructions on how to do this, see Calibrate IMUs.

  4. Create a New Trial (see Capture to sensor, Step 4, but note that the capture options differ, as shown in the above table).

  5. Tap Start Capture at the bottom of the screen.
    Note that when Global Angles is selected, Low G Accelerometer, Gyroscope, and Magnetometer are also captured and the capture rate is reduced to 225 Hz (A, G) 70 Hz (M) for the Low G sensor.
  6. Select the required sensors (see Capture to sensor, Step 7).
    If you chose to capture Global Angles, one or more of the sensors may be displayed with a 'Require calibration' icon or a 'Calibrated' icon    at its top right. For further explanation, see the next step.

  7. Tap Start Capture.
    To add notes during capture, tap Notes (top right).
    To add a region of interest, tap Start a region of interest at the top of the screen (for details, see Work with regions of interest).

    If you chose to capture Global Angles:

    1. If one or more of the selected sensors is displayed with a 'Require calibration' icon at the top right, after you tap Start Capture, on the next screen, a message at the the bottom of the screen prompts you to begin calibration when the trial starts. 
      After several seconds, the capture pane is displayed. A message towards the top of the screen prompts you to calibrate the sensors. 
    2. For more information on calibration, tap the How to calibrate link or see Calibrate IMUs.
    3. When you've finished moving the sensor, after 60 seconds the sensor icon changes to 'Calibrated' to indicate that calibration is occurring (calibration is a continuous process).
  8. When you have captured the required data, tap Stop Capture.
    Your new trial is displayed in the list of trials on the right of the screen (the most recent trial is at the top).
    Notice that in the filter at the top, Device is automatically selected, to display trials recorded directly to your iOS device. If required, you can change this to display trials captured to sensors, or all trials.

     

    You can play back a recorded video on your iOS device without exiting Capture.U by tapping the video icon in the list of trials.

     

    To add notes after capturing, slide the trial left and tap Notes.



  9. To export your data and any video/notes, slide the trial left and tap Export.
    If you recorded a video, you are asked if you want to include it in the export. Tap Yes, then tap the required export option.
    A .zip file containing your data (.csv), notes (.txt) and video (.mp4) is exported. 
    If you chose to capture Global Angles and export a .csv file, the CSV will include the Low G data (Low G accelerometer, gyroscope and magnetometer) and the global angles. The global angles are exported as quaternion components (Qx, Qy, Qz, Qr).

    Use Quicktime or another suitable video player, eg VLC Media Player, to view the downloaded video file.

Export regions of interest from a device

  1. On the region of interest, swipe left and tap Export.
  2. Locate the .zip file that is exported.
  3. To access the regions of interest data, extract all files from the .zip file.
    Two .csv files are extracted: one contains trial data and the other contains regions of interest data.

Capture in Real-Time Insight mode

Choose Real-Time Insight mode to capture movement for real-time data streaming from two sensors with video overlay. You can also define your own benchmarks (that is, you can set a threshold for alerts). For example, you can choose to be notified by a sound when a specified level is reached, so that you can easily recognize when an athlete hits a ball hard enough.

An example of using Real-Time Insight mode might be a coach and an athlete who want to review performance data together over multiple trials on an iOS device, then have the coach send the athlete a report of what was reviewed.

Note that as data is streamed over Bluetooth, external factors can cause dropped samples. If this is an issue, you can either interpolate between samples or use To Sensor mode instead, to avoid dropped samples altogether.

Watch the Vicon video, Using Real-Time Insight on YouTube.

Summary of Real-Time Insight mode:

No. of sensors:2
Data type:IMU data
Video:Video data real-time overlay
Axes:3
High G Accelerometer (default) or
Low G Accelerometer or Gyroscope (in either case, both exported) or
Global Angles (with Low G Accelerometer, Gyroscope and Magnetometer)
Output:Data (.csv), video (.mp4) and report (.pdf)
Range:Bluetooth: 20 m+
Capture rate:High G Accelerometer (default): 800 Hz
Low G Accelerometer and Gyroscope: 500 Hz 
Global Angles with Low G Accelerometer, Gyroscope and Magnetometer: 225 Hz (A, G) and 70 Hz (M)

To use Real-Time Insight mode:

  1. Open the Capture.U app.
  2. In the Capture section tap Real-Time Insight.
  3. At the bottom of the screen, select either Acceleration (x, y, z, or Resultant and Low G or High G) or Rotation (x, y, or z).
    Note that Resultant is the peak resultant acceleration, which is calculated by

    With the High G accelerometer selected, the resultant acceleration can reach up to 346 G.
    With the the Low G accelerometer selected, the resultant acceleration can reach up to 26 G.

    To enable Global Angles, select Rotation and ensure Global is selected.



    Global angles are streamed in real time on the graph. They are visualized as Euler angles (XYZ rotation order) and exported as quaternion components (Qx, Qy, Qz, Qr). 
    Note that when Global Angles is selected,  Low G Accelerometer, Gyroscope, and Magnetometer are also captured and the capture rate is reduced to 225 Hz (A, G) 70 Hz (M) for the Low G sensor. 
  4. At the bottom left of the screen, tap Select Sensors.



    While you are selecting sensors, if you chose to capture Global Angles, one or more of the sensors may be displayed with a 'Require calibration' icon or a 'Calibrated' icon at its top right. For further explanation, see Step 6.
  5. Select up to two sensors (for details, see Capture to sensor, Step 7), and then tap Set.



  6. At the bottom of the screen, tap Start.

    If you chose to capture Global Angles: 

    1. If one or more of the selected sensors requires calibration, after you tap Start to start capture, on the next screen, a message at the the bottom of the screen prompts you to begin calibration when the trial starts.
    2. Calibrate any sensors that are uncalibrated. For more information on calibration, see Calibrate IMUs.
    3. When you've finished moving the sensor, to verify your calibration, check that the graphs for all three axes are now at zero.
  7. To play a sound when a specified level is reached, in the Benchmarks area, enter the required values in the benchmark fields.
    The values are indicated by a shaded area on the graph.
  8. To view and optionally record real-time video (recorded at 1920 x 1080), tap the Video icon at the top right of the screen.
    The graph is overlaid on the video. To make the graph easier to see, the controls at the top of the screen enable you to change the thickness of the lines (slide right to increase line thickness), the opacity of the graph, and select a dark or light version.
     
      

  9. To see statistics for the capture in real time, tap the Statistics icon , towards the bottom right of the screen.
    The minimum and maximum values detected by the sensors are displayed, in addition to how many times the benchmark values have been reached.



  10. When you have captured the required movement, tap Stop
  11. From the export icons, select the required export type (file or video):
    • To save a video to your device, tap the Video icon (top right) and then tap Save.


      Depending on the length of your video, this may take some time. Don't tap Save again, but wait until the video is saved.

      Find saved videos on the Photos tab in the Photos app .
    • To export either a report (.pdf) or data (.csv), or to browse previously recorded videos, tap the File icon (top right).

       

      • If you choose Export to PDF, you can add a title in the PDF preview that is displayed.
        The preview shows the information that will be displayed in the exported PDF, with statistics information at the top of the page, a Focused view of the graph (showing the region of interest) and Full Range view (showing the whole range). This lets you check that the graph is as required before you export it. If it isn't, tap Cancel, change the Acceleration and/or Rotation to show a graph of the required view (X, Y, Z, or Resultant) and tap Export to PDF again.
        When you're happy with the preview, tap Export at the top to export the PDF.

          

      • If you choose Export to CSV, the data values exported can be X, Y and Z, but not Resultant.

        If you export Global Angles , the data is exported as quarternion components (Qx, Qy, Qz, Qr).




        If either Low G or Gyroscope is selected, both Low G and Gyroscope are exported.

      • If you choose Browse Video, previously captured Real-Time Insight videos are listed. Tap to select a video, then play a minimized preview by tapping the Play icon at the bottom, or tap Use at the top right to play in full-screen mode. 

Capture in AR Visualization mode

Choose AR Visualization mode to explore how using the ARKit with Capture.U can enhance your in-field capture experience while you're capturing IMU and reference video data.

Note that as data is streamed over Bluetooth, external factors can cause dropped samples. If this is an issue, you can either interpolate between samples or use To Sensor mode instead, to avoid dropped samples altogether.

Important
To access the AR Visualization capture mode, your iOS device must:

  • Be compatible with the Apple ARKit 3
  • Use iOS 13, with the Apple A12 Bionic chip (or later)

If you select this capture mode on an iOS device that doesn't meet these requirements, a message warns you that your device is incompatible, and you are unable to proceed in this mode.

Summary of AR Visualization mode:

No. of sensors:2
Data type:IMU data
Video:Video data real-time overlay
Output variables:4
Joint Angles (default)
High G Accelerometer or
Low G Accelerometer or Gyroscope (in either case, both exported) or
Global Angles (with Low G Accelerometer, Gyroscope and Magnetometer)
Output:Data (.csv), video (.mp4) and report (.pdf)
Range:Bluetooth: 20 m+
Capture rate:

Joint Angles: 60 Hz
High G Accelerometer (default): 800 Hz
Low G Accelerometer and Gyroscope: 500 Hz 
Global Angles with Low G Accelerometer, Gyroscope and Magnetometer: 225 Hz (A, G) and 70 Hz (M)

To use AR Visualization mode:

  1. Open the Capture.U app.
  2. In the Visualizations section tap AR Visualization.
  3. Select one of these options:
    • Acceleration (x, y, z, or Resultant and Low G or High G)
      Note that Resultant is the peak resultant acceleration, which is calculated by

      With the High G accelerometer selected, the resultant acceleration can reach up to 346 G.
      With the the Low G accelerometer selected, the resultant acceleration can reach up to 26 G.
    • Rotation (x, y, or z)
      To enable Global Angles, select Rotation and ensure Global is selected.



      Global angles are streamed in real time on the graph. They are visualized as Euler angles (XYZ rotation order) and exported as quaternion components (Qx, Qy, Qz, Qr).
      Note that when Global Angles is selected, Low G Accelerometer, Gyroscope, and Magnetometer are also captured and the capture rate is reduced to 225 Hz (A, G) 70 Hz (M) for the Low G sensor.

    • Joints, which lets you select two joint angles that are derived from the Apple ARKit 3 (tap Joint 1, select the required joint, then tap Joint 2 to select it). 


  4. At the top right of the screen, you can select whether the joint transforms are model transforms (relative to the root joint) or local transforms (relative to the parent). The default setting is Model.

     

  5. At the bottom left of the screen, tap Select Sensors

     

    While you are selecting sensors, if you chose to capture Global Angles, one or more of the sensors may be displayed with a 'Require calibration' icon or a 'Calibrated' icon at its top right. For further explanation, see Step 7.

  6. Select up to two sensors (for details, see Capture to sensor, Step 7), and then tap Set.



  7. At the bottom of the screen, tap Start.

    If you chose to capture Global Angles:

    1. If one or more of the selected sensors requires calibration, after you tap Start to start capture, on the next screen, a message at the the bottom of the screen prompts you to begin calibration when the trial starts. 
    2. Calibrate any sensors that are uncalibrated. For more information on calibration, see Calibrate IMUs.
    3. When you've finished moving the sensor, to verify your calibration, check that the graphs for all three axes are now at zero.
  8. To play a sound when a specified level is reached, in the Benchmarks area, enter the required values in the benchmark fields.
    The values are indicated by a shaded area on the graph.
  9. To record real-time video (recorded at 1920 x 1080), tap the Video icon at the top right of the screen.
    The graph is overlaid on the video. To make the graph easier to see, the controls at the top of the screen enable you to change the thickness of the lines (slide right to increase line thickness), the opacity of the graph, and select a dark or light version.
     
     

    When a subject is visible, the AR figure automatically overlays its image.

     

  10. To offset the skeleton from the tracked subject, use the Model Offset slider at the top left of the screen to apply the required offset.

     

  11. To enable or disable 2D and 3D skeleton visualization, select the required 2D Skeleton and 3D Skeleton option(s) below the Video icon.
    You can select 2D, 3D, or both.

  12. To see statistics for the capture in real time, tap the Statistics icon , towards the bottom right of the screen.
    The minimum and maximum values detected by the sensors are displayed, in addition to how many times the benchmark values have been reached.

     

  13. When you have captured the required movement, tap Stop.
  14. From the export icons, select the required export type (file or video):
    • To save a video to your device, tap the Video icon (top right) and then tap Save.


      Depending on the length of your video, this may take some time. Don't tap Save again, but wait until the video is saved.

      Find saved videos on the Photos tab in the Photos app .

      • If you choose Export to PDF, you can add a title in the PDF preview that is displayed.
        The preview shows the information that will be displayed in the exported PDF, with statistics information at the top of the page, a Focused view of the graph (showing the region of interest) and Full Range view (showing the whole range). This lets you check that the graph is as required before you export it. If it isn't, tap Cancel, change the Joints, Acceleration and/or Rotation to show a graph of the required view (X, Y, Z, or Resultant) and tap Export to PDF again.
        When you're happy with the preview, tap Export at the top to export the PDF.

         
      • If you choose Export to CSV, the data values exported can be X, Y and Z, but not Resultant.

        If you chose to display High G acceleration, High-G and joint data is exported.

        If you chose to display Joints, Low-G accelerometer and gyroscope data is exported with the joint data.

        If you export Global Angles, the data exported is in the format: 2D joints (x and y, which are positions in screen space where the joint was tracked via image processing), 3D joint translations (Tx, Ty, Tz, relative to the root joint if model transforms are selected, or relative to the parent joint if local transforms are selected) and in quaternion format: Qx, Qy, Qz, Qr, with Qr being the real component representing the rotation.

        To export either a report (.pdf) or data (.csv), or to browse previously recorded videos, tap the File icon (top right).
         

      • If you choose Browse Video, previously captured videos are listed. Tap to select a video, then play a minimized preview by tapping the Play icon at the bottom, or tap Use at the top right to play in full-screen mode. 

Run Activity Widget demo

The Activity Widgets provide pre-defined workflows that have output metrics.

Activity Widgets might be particularly useful in situations where a quick assessment with minimal/no user setup is required, for example, in undergraduate research projects, grass-roots sports, etc.

For a quick demonstration, you can view an animated GIF example. To do this:

  1. From the Activity Widgets, select Swimming.
  2. Hold the iOS device in landscape orientation.
  3. Tap the screen to run the example through each workflow screen.
  4. When you have tapped through all the screens, you are returned to the home screen.
    This provides an overview of the workflow for the activity widgets.


    To exit the Swimming GIF example at any time, tap Home.
    You are returned to the Capture.U app home screen.

Further, fully interactive Activity Widgets are planned.