To enable you to review the data you captured in your movement trials (see Capture movement trials), Vicon Nexus offers a number of tools. You can use the time bar to manually scrub through the trial, or to assess your trials quickly and easily, you can use the automated data quality features of Nexus.
For more information, see:
You can quickly obtain feedback on the data quality of all your trials on the Data Management tab.
To display quality information:
On the default Data Management tab, the Quality column displays data quality information about each trial.
The information displayed (from left to right in the Quality column) is:
If you are using a custom scheme for the Data Management tab, to display a Quality column, you can either revert to the default layout or, to add a Quality column to your custom scheme:
To review trial data using the time bar:
To automatically display both views, in the View Type list on the Nexus toolbar, select Data Correction. Using a split layout with both a 3D Perspective and a Graph view enables you to display the results of your editing actions and to select specific trajectories, frame ranges, and gaps in trajectories. Since the graphs indicate what changes have been made to the data and by which tool, you can immediately see the results of any edits you have made and determine if you want to change it again or adjust the data, using a different tool in the Gap Filling section.
To display a context menu in which you can reset the timescale on the timeline, set the playback speed, or specify the length of trajectory tails, click the ellipsis (...) in the time bar controls, or right-click the time bar.
The data Quality pane, a tab in the Communications window, provides both a broad overview of data quality for a subject across the entire trial and a way to examine the health of individual trajectories. It also enables you to navigate to the highlighted issues.
The three most common data issues that you need to find and resolve are:
The Quality tab helps you to find this information:
Overview of the health of the whole trial (Labeling column) The text in each rectangle indicates the number of unused markers, any gaps, and the percentage of markers labeled. As a quick indicator, to enable you to assess whether to continue working with the trial, the color green indicates good health, red indicates probable major issues, and colors between the two (yellow, amber, orange) indicates that the overall health of the trial lies somewhere between these extremes.
For example, a good trial, worth further work, would be indicated by:
A low quality trial, which would probably have to be re-run, would be indicated by:
Individual trajectories. If you hover the mouse over a blob, the blob displays information about the trajectory. If you click on it to select it, information about the trajectory is displayed in the Selection column on the right. For more information, see Navigate to gaps using the data quality features.
General trial information/selected trajectory Information (Selection column). If no blob is selected, general information about the currently loaded trial is displayed. If a blob is selected, information about the trajectory is displayed.
Display options (Options column): Enables you to configure the display options for the data Quality tab. Alternatively, you can open the Options dialog box (F7), click Data Quality Panel Options on the left, and change the properties as required. To save any changes to these settings, click the Save current configuration button in the Options dialog box.
The Graph view enables you to view and fix gaps for a selected trajectory.
To display gaps:
The default Data Correction view type displays a 3D Perspective view above a Graph view.
You can turn Data Correction view on or off in the Options dialog box, as described below.
When the Data Correction view is turned on, it is automatically displayed when you navigate using the data Quality pane.
If you would prefer the Data Correction view to appear differently (for example, displaying the Graph above the 3D Perspective view), you can save your own preferred view and select this instead.
To configure the Data Correction view:
In addition to viewing data quality on the Quality tab and Graph and Data Correction views, you can also view data quality as a heat map on the time bar, to get an overall picture of the current trial.
To turn on the heat map overlay:
When you click on a trajectory on the Quality tab, the time bar shows gaps for the selected trajectory.
To select multiple trajectories, on the Quality tab, CTRL+click the required blobs.
When multiple trajectories are selected, the heat map's color gradient system is activated.
Lighter colors show where one of the trajectories has a gap but other selected trajectories do not. Darker areas show where a number of selected trajectories has a gap.
The following images show two trajectories selected. The darker area indicates gaps in both trajectories.
As more trajectories are added the view starts to morph from individuals gaps for one or two trajectories, to areas in the volume/time where there are issues.
Using the Quality tab and the Data Correction view type, you can quickly navigate to gaps in data, and use the Zoom, Translate, and Rotate options for a better view.
To quickly navigate to gaps:
On the data Quality tab, you can move to the next trajectory and previous trajectory by pressing CTRL+PgUp and CTRL+PgDown.
The Zoom, Translate and Rotate options for viewing a gap make it easier to zoom in on and fix selected gaps.
To view gaps more clearly: