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This section covers the purpose of the controls available in the HoloLens2ModelTrackingSetup scene. The controls are linked with the hand menu, so you have to look at the palm of your hand in order to show this menu. The following image shows an overview of the available controls:
Legend:
The button in the top left of the menu (see (1) in the overview image above) toggles a window in the background showing the debug image. This greyscale image is the one on which tracking is performed. The line model is overlaid on top.
If you enable the parameters, the application will automatically enable the debug image. After finishing parameter adjustment and closing the parameter panel, the debug image will be disabled.
The Pause Tracking button in the top right of the menu (see (2) in the overview image above) halts tracking. The object will then remain at the current position until you Resume the tracking again. This feature might be useful, if you only want to position the object once and save processing power on HoloLens.
The Parameters On button (see (3) in the overview image above) enables the parameter panel and the debug image. In this panel, you can see buttons for different parameters, which can be selected to adjust the corresponding parameter. An overview over these parameters and their meaning can be found at the Optional Tracking Parameters page. The debug image in the background should help to see the effect of the parameters on the tracking.
Selecting a parameter displays a slider for its adjustment. The line model will only be update after you finished setting the parameter.
The only parameter without a slider is the field of view. It is only used on HoloLens and not available on other platforms. In the following graphic, you can see the effect of this parameter: It adjusts the area covered by the camera image. A narrow field of view results in better tracking results, given that the user is looking directly at the target object and that the object fits entirely inside the camera image. A wide field of view helps stabilize the tracking in cases where the user is unable to see the object in its entirety. In other words: If the object is either very close or very large.
The Reset button (see (4) in the overview image above) resets tracking and returns to initialization mode. In other words, the currently tracked pose is dropped and the tracking state switches to lost. Note for advanced users: This internally performs a Reset Hard command.
The Save Configuration button (see (5) in the overview image above) saves the current tracking parameters and init pose for the tracker into a .vl configuration file.
By default this file's URI is capture-dir:VisionLib/savedTrackingParameterConfiguration.vl. This folder is accessible via the Windows File Explorer on the HoloLens device under the path Internal Storage/Videos/Captures/VisionLib/savedTrackingParameterConfiguration.vl A custom URI can be set via Save Configuration URI in the hierarchy on Model Tracker Parameters on VLTracking > VLModelTracker. File schemes (see File Access) are supported. On the HoloLens, we recommended using the capture-dir scheme to be able to access the file from the Windows File Explorer.