For information on the new features and enhancements provided by Nexus 2.7, see the following topics:
, available on YouTube. ‌For more detail on the new functionality, watch the Vicon video,
Cycle visualization in the time bar
Location: Nexus time bar and Options dialog box (F7)
By default, all the cycles (gait or other) that have been defined by sets of time bar events, are displayed on the time bar.
This provides an easy way to identify:
- How many cycles are defined
- Where they are temporally
- Whether they are associated with force plate activity (indicated by solid color instead of colored outline only)
- How large they are (number of frames)
- Whether the left or right side is indicated:
- Left = Red
- Right = Green
To turn the visual display on or off or to change the default color options and other visual indicators, in the Options dialog box (press F7), on the left side click Time Bar and change the required properties on the right.
To turn on or off the display of the frame count, right-click on the time bar and select or clear Show Cycle Frame Count.
Display selected components in Quick Reports
Location: Window menu > Quick Reports (or F4)
When you create a Quick Report, you can now select and display individual components and outputs, - x, y or z, in addition to displaying all three simultaneously:
To display only the required components, in the Model Outputs tree, clear the check boxes for the unwanted components.
For example, if you are interested in Ankle Moment X only, you can select this only.
Improved feedback for camera calibration
Location: Tools pane > System Calibration tab > Camera Calibration Feedback section
You can now use the new features in the Camera Calibration Feedback section of the System Calibration Tools pane to export your calibration, to identify calibration issues or to ensure that the current calibration conforms to an established standard.
Export a calibration as a CSV file
You can now export the current calibration as a .csv file. This helps you to monitor your calibration standards over time.
To export a calibration as a CSV file:
- In the Camera Calibration Feedback section, right-click and then click Export.
- Enter a file name, ensure the file extension is .csv and click Save.
New functionality in the Camera Calibration Feedback section enables you to compare the current calibration results with the results from the previous calibration.
To compare the current and last calibrations:
- In the Camera Calibration Feedback section, right-click and then select Show Differences.
The World Error and Image Error columns display the differences between the two calibrations.
If the results from the latest calibration are better (ie produce smaller errors) than the previous one, the columns are displayed in green to yelllow.
If the results from the latest calibration are worse (ie produce larger errors) than the previous one, the columns are displayed in red to orange.
Set calibration error threshold
A new feature enables you to specify a maximum calibration error, above which cameras are flagged as having an error that is higher than the threshold that you have set. To use this feature, at the bottom of the the Camera Calibration Feedback section, you can set the error threshold (World or Image). After calibration, in the Camera Calibration Feedback section, cameras with an error greater than this value are displayed with a yellow warning icon instead of the normal blue camera icon. The default setting (0.000) disables any warnings.
In the following example, the error threshold is set to 0.5mm, so that the three cameras with a calibration error greater than this are displayed with a warning icon:
If you are working with a large number of cameras, it is useful to be able to sort the results to enable you to quickly identify problematic cameras. You can now sort the columns in the Camera Calibration Feedback section by clicking on the required column heading.
The default sorting is on the camera number (low to high):
To make it easy to find cameras with the highest errors, you can sort on World Error or Image Error, displaying the cameras with the highest errors at the top of the column:
Enhanced Log notifications
You are now alerted to important errors by popup notifications that are briefly displayed at the bottom right of the Nexus window.
If you are using the default sounds supplied with Nexus and have audio enabled, a relevant sound clip is also played.
To view further details about the error in the Log, click the notification.
The notification disappears after four seconds.
New ProCalc pipeline operation
Location: Tools pane > Pipelines tab > Data Processing pipeline operations > Run ProCalc Operation
A new pipeline operation enables you to run ProCalc scripts/models directly from Nexus.
To run ProCalc with Vicon Nexus 2.7, you must install ProCalc 1.2.
To use the new Run ProCalc Operation pipeline operation:
- On the Pipelines Tools tab, double-click Run ProCalc Operation to add it to the current pipeline in the usual way.
- In the Properties pane, specify the program folder, the operational schemes and other options.
- Run the ProCalc operation to perform the required calculations.
For more information on Procalc, see the Vicon Procalc documentation.
Stream and capture IMU data
Location: System Resources pane > Local Vicon System node > Devices node > Add Digital Device > Add IMeasureU Sensor
To enable you to capture data from Vicon IMUs (Inertial Measurement Units) and optical markers simultaneously, you can now use IMUs as digital devices in Nexus to stream and capture data. You can use IMUs to preview data in real time and to capture data onto the IMU's internal memory. You can then plug the IMUs into your PC via USB and use Nexus to download the captured data.
Vicon IMUs are supported for use with Nexus for research purposes only. For full sensor safety and regulatory details, see the Vicon Blue Trident Model V2 Safety and Regulatory Information, which is also available as a PDF.
Before you begin using IMUs with Nexus, note the following points:
- Windows 10 and above only is supported. Ensure the latest Windows 10 updates are installed.
- To use IMUs in Nexus, first plug the supplied Bluetooth (BLE) dongle into the relevant Windows PC. Ensure that its drivers have been updated: you can do this using the Windows Device Manager.
- To enable further setup and control of your IMUs after they are paired and recognized by Windows 10, you can download IMU Lightning desktop software. IMU Lightning enables you to see the status of IMUs outside of Nexus and is useful in certain troubleshooting situations.
- IMUs have three collection modes: 100 Hz, 250 Hz or 500 Hz. To accommodate the IMUs, ensure that your Vicon system is running at a compatible frame rate.
- Nexus supports the use of up to four current IMUs.
- You can transfer the data that is collected and stored on your IMUs onto your PC using the new IMU Transfer pane in Nexus (see Transfer data from IMUs into Nexus).
- To enable transfers to work, ensure you have downloaded and installed the CP210x USB to UART Bridge VCP Drivers.
The following topics are covered:
Capture data with IMUs
The following are brief notes on working with IMUs with Nexus. For more information on setting up and using IMUs to stream and capture data, see the IMeasureU documentation.
‌, ‌, and , available on YouTube. ‌For more detail on working with IMUs and Nexus, watch the Vicon videos,
- If necessary (see previous points), download and install IMU Lightning.
- Ensure that the Bluetooth dongle is plugged into the PC and that its drivers are up-to-date.
Turn on the IMUs and pair them to the relevant Windows computer, via Bluetooth settings in Windows 10.
- In Nexus, add the IMUs as digital devices and in the Properties pane, specify the required settings:
- In the System Resources pane, expand the Local Vicon System node, then right-click the Devices node, point to Add Digital Device and click Add IMeasureU Sensor.
In the Properties pane below, specify a Name and Sensor Number:
Property Description Name The identifier that you want to give to the IMU. Sensor Number The unique serial number of the device, which is found on the tag on the side of the IMU. Although you enter only the digits on the tag, this is an eight-digit number that is padded with four zeros when displayed in the Log.
Note that if the connection to the IMU is lost (the device is displayed as gray in the System Resources pane), you can click the Sensor Reconnect button to reconnect. This button is not available while you are capturing a trial.
- If necessary, change the collection mode (frequency) at which the IMUs are to run: 100 Hz, 250 Hz or 500 Hz.
To do this:
- In the Resources list, ensure the IMUs are selected.
- To display the axes for the IMUs, in the view pane, select Graph view.
- In the Properties pane, from the Mode list, select the required frequency.
- In the Graph view, the graphs change to reflect the selection.
If you need to calibrate the IMUs (normally only necessary when you update the camera firmware or if an offset occurs), see Calibrate IMUs. Note that, for calibration, you must set the collection mode to 100 Hz.
Attach the IMUs to the subject.
Set up and start capture in the usual way (see Capture the required movement).
While the IMUs are connected to Nexus, a real-time preview of data streaming from the IMUs is displayed. This preview data stream is supplied to Nexus at 50 Hz, regardless of the trial collection rate (100 Hz, 250 Hz or 500 Hz). You can view this preview data in Live mode in Nexus.
The preview stream is optimized for low latency data visibility and may therefore have small frame gaps where data does not appear.
When trial capture starts, the IMU simultaneously enables the display of preview data at 50 Hz and writes data to its internal memory.
Gaps in the preview data do not indicate gaps in the data that is written to memory.
- When you stop a trial capture, an .x1d file that contains the preview data that is displayed in the Graph view is saved into the current Session folder and is displayed with a purple A icon on the Data Management tab.
When you have finished capturing data, plug the IMUs into your PC using the supplied USB cables.
Manage your captured IMU data
After you have finished capturing data and have plugged the IMUs into the PC, you use the buttons in the IMU Transfer pane in Nexus to work with the data and transfer it.
To help you decide whether to transfer recorded data, you can check the preview data by playing it in Offline mode first.
To open the IMU Transfer pane, in the Communications pane expand the File Transfer/Batch Processing interfaceand click the IMU Transfer button .
The connected IMUs and the trials that were recorded onto them are listed.
Depending on what you want to do with the data that you have captured, choose the appropriate option.
|To do this||Take this action|
|Select one or more trials|
Click, SHIFT+click or click Select All
After you have transferred trials (see Transfer data from IMUs), you may want to use Select Transferred, or Select Untransferred.
|Remove selected trials from the list in the IMU Transfer pane.|
Select the trials that you want to remove and click Remove Selected Trials.
The trials are removed from the IMU Transfer list, but remain on the IMU.
|Remove from Nexus all references to selected IMUs and their related trials.|
Select the the IMUs that you want to remove and click Remove Selected Devices.
The selected IMUs and their trials are removed from the IMU Transfer list, but the trials remain on the IMUs.
|Remove from one or more IMUs all collected trials, and remove the IMU and its trials from the list in the IMU Transfer Pane.|
Select the the IMU(s) that contains the trials that you want to remove and click Erase Selected Devices.
All data is removed from the selected IMU(s) and the IMU is removed from the IMU Transfer List.
|Transfer trial data from the IMUs to the Session folder in Nexus on your PC.||See Transfer data from IMUs.|
Transfer data from IMUs
To transfer the data from the IMU(s) to the Session folder in Nexus:
- Ensure you have downloaded and installed the CP210x USB to UART Bridge VCP Drivers.
- In the IMU Transfer pane, select the required files for transfer to the Session folder.
- At the bottom of the pane, click the Transfer Files button.
When transfer is complete, the Progress column in the IMU Transfer pane changes to Transferred for the IMUs and Transfer Succeeded in green for each successfully transferred trial.
After the transfer operation, for each trial, you can find the following files in the Session folder:
- An .x1d containing the preview data (50Hz)
- An .imu file containing the higher quality data (100 Hz, 250 Hz, or 500 Hz) from the IMU
- You can now view and process the IMU data along with the rest of the trial data.
Export IMU data
You can export data captured using IMUs by running the appropriate pipeline.
To export IMU data:
- If you want to select data from only some devices, in the System Resources pane, ensure the required IMUs are selected.
- In the Pipeline Tools pane, expand File Export and double-click Export ASCII to add it to the current pipeline.
- In the Properties pane, ensure that the settings are as required. In the Devices section, if necessary, change the Devices for Export list to specify your selection.
- Run the Export ASCII operation.
To open the exported file in Microsoft® Excel®, on the Data Management tab, click the relevant C icon and then click the filename.
The data is displayed in an Excel spreadsheet.
IMUs are already calibrated when they are supplied to you, and the calibration is stored on the IMU, so you only need to re-calibrate when you update the camera firmware or if an offset of the IMU occurs.
Note that IMUs can be calibrated at 100 Hz only.
To calibrate IMUs:
- Select the IMU(s) that you want to calibrate and in the Properties pane, ensure Advanced properties are displayed.
- Ensure that the IMUs are static and are not subject to vibration, and positioned with the Z+ axis pointing up or down.
- In the General section of the Properties pane, click Calibrate Sensor.
Pair an IMU to a different device
After an IMU is paired with a Bluetooth (BLE) dongle (central device), the IMU will only work with that dongle and will reject requests from other central devices (built-in Bluetooth or BLE dongle). To pair the IMU with a different central device (eg a dongle on a different Windows computer), you must erase the stored connection information.
To erase stored connection information:
- Turn on the IMU and plug it into the PC via USB.
- Before downloading any data, on the IMeasureU Lightning toolbar, click Clear Bluetooth.
This deletes the stored connection information. At the bottom left of the screen a message confirms that the cache has been cleared.
You will not have to repeat a pairing operation unless you:
- Remove or reconfigure your Bluetooth receiver (unplug the dongle etc...)
- Manually remove the pairing