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For information on installing and using the Capture.U app, see these topics:

What's new in the Capture.U app 1.2?

To use the Capture.U app 1.2, you must upgrade the sensor firmware to 9.0.4 or later. To do this, you must use Capture.U Desktop 1.1.1 or later.

The latest version of the Capture.U app provides these new features:

For information on previous versions of the Capture.U app, see the PDFs Vicon Capture.U 1.1 User Guide and Vicon Capture.U 1.0 User Guide.

Global angles in all capture modes

You can now capture global angles in all capture modes.

 

  • In To Sensor mode, you can capture all 15 axes (High G, Low G Accelerometer, Gyroscope, Magnetometer, and Global Angles).
    You can export the captured data, including global angles, with Capture.U Desktop.

  • In To Device mode, you can you can stream, capture and export Low G Accelerometer, Gyroscope, Magnetometer, and Global Angles. You can also export the data as a CSV file via the app. 

  • In Real-time Insight and AR Visualization modes, if Global Angles are displayed, you can capture, stream and display them in real time. You can also export the data as a CSV file.

In Real-time Insight and AR Visualization modes, global angles are visualized as Euler angles.

From all capture modes, global angles are exported as quaternion components (Qx, Qy, Qz, Qr).

For more information, see the relevant capture mode.

Remember previously selected sensors

In all capture modes, within a session, the Capture.U app now remembers the sensors that you selected in the previous trial. This enables you to avoid having to re-select the sensors for every trial. Note that if you create a new session, the sensors are not remembered from the previous session.

In To Sensor and To Device modes, when you select the Home tab or close the app, if there is a current session, the selected sensors are remembered.

In Real-Time Insight and AR Visualization modes, the selected sensors are remembered when the capture is stopped, so you don't need to re-select them for the next capture. If you select the Home tab and return to Real-Time Insight or AR Visualization mode, the selected sensors are not remembered.

Ability to clear selected sensors

Related to the ability to remember previously selected sensors for a specific session (see above), if you decide to change the sensor selection for the next trial, you can avoid having to manually deselect the selected sensors by using the new Deselect All option at the top right corner of the Sensor selection screen to clear selected sensors.

Remember previously selected settings

In To Sensor and To Device modes, Capture.U now remembers the previously selected settings so that you don’t have to manually select the desired axes or video settings (if capture video was selected) for every new trial within a session. Only the settings captured within a session are remembered: when you start a new session, the settings are not remembered.

Auto-increment trial names

When you're setting up the To Sensor and To Device capture modes, trial names are now auto-incremented (eg, after the initial trial, which is automatically given the same name as the session, MyTrial becomes MyTrial-1 , MyTrial-2 , etc), so that you don't have to manually enter a trial name each time, giving you a faster turnaround when starting trials.

For details, see Capture to sensor and Capture to device.

Increase graph overlay thickness

In Real-time Insight and AR Visualization modes, you can now increase the overlay thickness of the lines displayed on the data graph, so that when you’re outside in a sunny environment, you can view the real-time data stream more easily.

For details, see Step 8 of Capture in Real-time Insight mode or Step 9 of Capture in AR Visualization mode.

Ability to search the sensors list

In all capture modes, you can now enter and search for a sensor number so that you don't have to scroll the sensor list or use tap-to-select to find a sensor.

Requirements for the Capture.U app

The Vicon Capture.U app is available for iOS devices only.

Before you begin, ensure your iOS device meets or exceeds these requirements:

  • iOS 11 and later - with BLE 4.2 and later devices (1.1 and 1.2)
    To access AR Visualization capture mode, Vicon recommends an iOS 13 device, BLE 5 and an Apple A12 Bionic or later chip device.
  • iOS 13 and BLE 4.2 devices:
    • iPad 5th generation (2017) (A9), iPad Air 2 (A8X),  iPad mini 4 (A8),
      9.7-inch: iPad Pro (A9X), iPad 6th generation (2018) (A10),
      10.5-inch: iPad Pro (A10X),
      12.9-inch: iPad Pro 1st generation (A9X) and iPad Pro 2nd generation (A10X)
    • iPhone 6s (A9), iPhone 6s Plus (A9), iPhone 7 (A10), iPhone 7 Plus (A10)

For optimum performance, and to access all available capture modes, this specification is recommended:

  • iOS 13, BLE 5.0 and Apple A12 Bionic (or later) chip devices.

This table lists the latest iOS 13 supported devices:

iOS devices
(iOS 13)
Bluetooth 4.2
(Bionic chip)
Bluetooth 5
(Bionic chip)
Bluetooth 5 with Apple A12 Bionic chip or later (recommended)
iPhonesiPhone 6s (A9)

iPhone 6s Plus (A9)

iPhone 7 (A10)

iPhone 7 Plus (A10)

iPhone 8 (A11)

iPhone 8 Plus (A11)

iPhone X (A11)

iPhone Xs (A12)

iPhone Xs Max (A12)

iPhone XR (A12)

iPhone 11 (A13)

iPhone 11 Pro (A13)

iPhone SE (A13)

iPhone Xs (A12)

iPhone Xs Max (A12)

iPhone XR (A12)

iPhone 11 (A13)

iPhone 11 Pro (A13)

iPhone SE (A13)

iPads12.9-inch iPad Pro
2nd generation (A10X)

12.9-inch iPad Pro
1st generation (A9X)

10.5-inch iPad Pro (A10X)

9.7-inch iPad Pro (A9X)

9.7-inch iPad
6th generation (2018) (A10)

iPad
5th generation (2017) (A9)

iPad
7th generation (A10)

iPad Air 2 (A8X)

iPad mini 4 (A8)
12.9-inch iPad Pro
3rd generation (A12X)

11-inch iPad Pro (A12X)

iPad Air
3rd generation (A12)

iPad mini
5th generation (A12)
12 .9-inch iPad Pro
3rd generation (A12X)

12.9-inch iPad Pro
(4th generation) (A12Z)

11-inch iPad Pro (A12X)

iPad Air
3rd generation (A12)

iPad mini
5th generation (A12)

Download and install the Capture.U app

To install Capture.U:

  • Download the Vicon Capture.U app  from the App Store to your iOS device.


    Capture.U supports only Vicon Blue Trident sensors. Blue Thunder sensors are not supported.

Attach Vicon IMU sensors to a subject

The method you use to attach the sensors to your subject depends on the type of movement you want to capture.

  • To capture the movement of a subject's limbs, you can attach the sensors using the supplied straps.
  • To capture the movement of other parts of the anatomy (for example, where movement of the vertebrae is of interest), you can attach sensors directly, using suitable tape.

To attach sensors to a subject using the supplied straps:

  1. Insert each sensor into its strap with the IMU symbol facing outwards.



  2. Attach the straps to the subject, ensuring that:
    1. The strap sits snugly against the limb.
    2. The sensor is oriented with the top (head) pointing in the same direction as the movement of the subject.
    3. The flashing LED is at the top of the strap.
      The following example shows a strap attached so that the sensor sits directly on the medial aspect of the tibia, just above the medial malleolus:

       

To attach sensors to a subject where straps are not used:

  1. Position the sensor on the subject, depending on the required sensor orientation.



  2. Secure the sensors using your preferred type of tape (for example, hypoallergenic, double-sided, micropore surgical tape).

Start Capture.U and choose a capture mode

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

    If you need to upgrade your Blue Trident sensors to Firmware 9, which enables you to use your sensors with both Capture.U and Vicon Nexus, when you start Capture.U the sensors are displayed with a yellow warning symbol, and a message alerts you to their status:



    Click OK, 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:


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 right, 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).

    Do not use an underscore as part of the name (eg, _2), as it is an invalid character in a trial name.

  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, 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 right 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 required sensors is displayed in orange and is labeled Reset required, see Reset sensors.
  8. At the bottom right, 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).
  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).

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

    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.

  5. Tap Start Capture at the bottom right 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).

  7. Tap Start Capture.
    To add notes during capture, tap Notes (top right).
  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.

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 left of the screen, tap Select Sensors.

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



  5. 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.

    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.

  6. At the bottom right of the screen, tap Start.
  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. At the bottom left of the screen, tap Select Sensors

     

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

     

  5. 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.

      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.

    • 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). 


  6. 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.

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

Calibrate IMUs

In all capture modes, if you plan to capture global angles, to ensure that the IMU sensor data is stable and to minimize drift, at the start of a day's capturing, you must calibrate the IMU sensors.

To calibrate the sensors:

  1. Start streaming global angles.
  2. Wave the sensor in a figure-of-eight for at least 10 seconds.
  3. Put the sensor on a flat surface.
  4. Wait until the data has stabilized.
    In Real-Time Insight and AR Visualization modes, you can observe that X angle is 0 and the Y angle is 0 (the figure-of-eight provides enough information for the sensor to self-calibrate). However, the Z angle may have a non-zero value, depending on how it is rotated to the magnetic north.
  5. Rotate the sensor on the flat surface until Z is also 0.
  6. You can now capture data in the required capture mode.

Reset sensors

When you select a capture mode and tap Select Sensors, if one or more of the sensors needs a reset, it is displayed in orange and is labeled Reset required.

This may happen, for example, if you close the app before stopping a capture.

You can reset sensors using the Reset sensors option. 

To reset sensors:

  1. Tap the Settings icon (the cog symbol, bottom right).

     

  2. Tap Reset sensors.

     

  3. Select the sensor by doing one of the following: 
    • Select Tap to Select and then tap the sensor twice.
      or
    • In the list in the app, tap the sensor name.
      or
    • At the top of the sensor list, in the Search field, enter the number of the sensor.
    The sensor is selected.
  4. Tap Reset Selected.

     

    The reset sensor(s) are now available and the app returns to the Settings window.
  5. To close the Settings window, tap the Back button or tap a blank area of the Capture.U screen.

Get help on the Capture.U app

  1. Tap the Settings icon (the cog symbol, bottom right).

     

  2. Tap Help.
  3. Tap one of the options:
  4. To close the Settings window, tap the Back button or tap a blank area of the Capture.U screen.

Addressed issues for the Capture.U app

The following issues were addressed in the current version of the Capture.U app:

  • In AR Visualization mode, exported CSV file names are correct in folders and sub-folders, whether exporting Acceleration, Rotation, or Joints.
  • In Real-Time Insight mode and you toggle the keyboard on and off during live capture, parts of the user interface are no longer cut off.
  • When creating a new trial on the iPad or iPad Pro, you can now select the X button to clear a trial name.
  • The displayed rate for Magnetometer (when only Magnetometer is selected) has been updated to illustrate the true capture rate of 112 Hz.

Known issues for the Capture.U app

IssueWorkaround
When using Real-Time Insight mode, if you have not enabled video, the controls at the top of the screen that enable you to change the opacity of the graph and to select a dark or light version of the graph are not selectable.

If you need to change the opacity of the graph and/or to select a dark or light version of the graph, ensure video is enabled. To do this, tap the Video icon at the top right of the screen.

The data rates displayed by the Capture.U app for the magnetometer do not always reflect its true values.
In To Sensor mode and To Device mode, if you select Magnetometer only, the rate is accurately represented in the displayed information (112 Hz LowG M Recorded and 112 Hz LowG M Streamed at 112 Hz respectively).
However, if other Low G inputs are also selected, the displayed value reflects the rate of the other inputs, and the magnetometer rate is not shown.
Be aware that the rate reported in the Capture.U app for Magnetometer is only accurate if Magnetometer only is selected, that is:
  • During standard capture, the magnetometer rate is 112 Hz.
  • If Global Angles are also selected, the rate is 70 Hz. 

If other Low G inputs are also selected, the displayed value reflects the rate of the other inputs.

When displaying or exporting global angle data, Nexus attempts to remove discontinuities, caused by restricting the helical angle to rotations of less than 180 degrees, by adding or removing multiples of 360 degrees of rotation to the helical angle vector. However, when the IMU approaches its original orientation after a full 360 degree rotation, the overall rotation in the underlying data is small and the axis of rotation at this time will generally not be parallel to the overall rotation vector of the gross movement. This may lead to apparent large excursions in the helical angle and a difference in the values displayed in graphs or exported from Nexus when compared with the unadjusted values exported from CaptureU.None. However, note that although the component values differ, they still describe equivalent rotations.
In Real-Time Insight and AR Visualization modes, saving a video takes longer than expected and a gray box may be displayed.Depending on the length of your video, saving may take some time. Don't tap Save again, but wait until the video is saved.
If after waiting, the app seems unresponsive and/or a gray box is displayed, the app may have terminated. Restart the device and flush the Bluetooth.
When capturing global angles in Real-Time Insight and AR Visualization modes, data may appear to drift.

Each day, or session, before you start capture, perform the following calibration:

  1. Start streaming global angles.
  2. Wave the sensor  in a figure-of-eight motion for at least 10 seconds.
  3. Put the sensor on a flat surface.
    Observe that X angle is 0 and the Y angle is 0 (the figure-of-eight provides enough information for the sensor to self-calibrate). However, the Z angle may have a non-zero value, depending on how it is rotated to the magnetic north.
  4. Rotate the sensor on the flat surface until Z is also 0.
In AR Visualization mode, the shoulder joints do not appear to be where you would expect them (ie, corresponding to the ball and socket joint at the top of the arm). Instead, they appear to refer to the neck-end of the clavicle (or in close proximity).None.

If you repeatedly enter and exit AR Visualization mode by tapping Home or exiting the app, the Capture.U app unexpectedly stops.

Restart the device and flush the Bluetooth.
The ARKit 3 joint data and the Vicon IMU data is not time-synced. To synchronize the data post-capture, ensure the subject performs a foot-stamp (or any other movement that shows a clear, recognizable signal in both streams) during capture.
When Capture.U is used on an iPhone, it remains in portrait orientation, even when the phone is rotated.None: this is intended behavior. When Capture.U is used on iPhones, for optimal use of the screen proportions, it is displayed in portrait mode only.
On iPhones, graphs are always exported in portrait orientation (side-by-side).None: this is intended behavior. As iPhones are locked to portrait orientation (see above), graphs are always exported in portrait orientation (side-by-side).
In Real-Time Insight mode, when you set benchmarks, you can't close the Benchmark keyboard.To close the Benchmark keyboard, tap the Real-Time Insight graph.
If trial and/or session names are followed by a double space, a period is automatically added. The period is an illegal character, so if you try to use a trial or session name that is followed by a period, the Capture.U app does not save it.Do not append a double space to trial or session names.
Downloaded High G accelerometer data may exhibit "latching". This is where, when the data becomes close to zero, its value is automatically rounded to zero.None