---
title: "Mask cameras"
canonical: "https://help.vicon.com/space/Tracker41/14320612/Mask%20cameras"
format: markdown
---
Before you begin calibrating, make sure that your camera views are clear of any unwanted reflections, whether they originate from markers or reflective materials in your lab. In either case, try to physically remove or cover the source of any reflections that are shown in each camera view as they can be mistaken for markers by the cameras. You can check the source of these reflections by using Video Preview Mode (see [Configure Vicon cameras](https://vicon-help.atlassian.net/wiki/spaces/Tracker41/pages/14319918)). If removing the source of the reflections is not possible, you must mask your cameras to remove the pixels caused by the reflections so that they don't influence the 3D data.

> ✅ **  Tip**  
> ✅ Physically removing unwanted reflections from your volume is preferable to masking, to ensure that you use all the pixels on your camera for 3D tracking.

<span style="color: #172b4d">If your camera view is not masked, you can see reflections represented by light pixels in the  </span> **Cameras** <span style="color: #172b4d">  view. </span>During masking, blue pixels are drawn in the **Cameras** view, enabling you to see how much of the view is masked.

> ℹ️ **Note**   
> ℹ️ If your volume has windows or skylights, the natural light level will vary throughout the day, so reflections can be difficult to mask. Ideally, to prevent any natural light from entering the volume, cover any windows with curtains/blinds. If this is not possible, mask any windows and reflections in Tracker, either automatically (if it's sunny enough) or manually.

> Macro (scroll-pagebreak)


    **To automatically mask reflections:**


1. Ensure you have removed from the capture volume any unnecessary objects, such as calibration objects, likely to cause background interference. Note that, to start masking, at least one camera must be contributing data.
2. In the **Workspace**, select the **Cameras** view.
3. In the **System** panel, select all the cameras (SHIFT+click or drag or right-click and then click **Select All Cameras**).
  :check_mark: **Tip**: If you are already in the cameras view with a single camera selected, double-click within the camera view to display all cameras.
4. In the **Camera Calibration** panel, under **Masking**, click **Mask All**.
  The button displays ** Stop **and at the top of the workspace, the menu bar changes color and ** Auto Mask Active **is displayed.
  On the cameras, the status lights turn cyan while auto masking is in progress.
  Tracker starts tracking the data visible to each of the connected cameras. Any camera masks created are displayed as blue cells in the **Cameras** views for affected cameras. If no data is visible to a particular camera, Tracker does not create any masks for it.
5. Once all the light pixels in each camera have turned to blue, click **Stop**. The duration of this process depends on the number of cameras in your system.
6. In the **Cameras** view for each camera, ensure that any unwanted reflections are eliminated. (Each view must either be completely blank or contain some blue pixels.)

If the automatic camera masking that is described above does not eliminate all the unwanted reflections, you can manually remove any remaining reflections as follows. 

> Macro (scroll-pagebreak)


    **To define camera masks manually:**


1. In the **System** panel (**Vicon Cameras** list) or **3D View**, select a single camera.
2. In the **Camera Calibration** panel, go to  the **Masking** section and ensure the advanced options are displayed (if necessary, click Advanced Parameters > Macro (inline-media-image)

 at the top right).
3. To begin editing the selected camera mask, click **Manual Mask Paint**.
4. In the **Cameras** view:
  - Alt+drag to select a mask area
  - Press E to add the current selection to the mask
  - Press R to remove the current selection
5. To apply the changes, click **Stop**.
  To revert to the original mask, click **Cancel**.

You can now wave the calibration wand throughout the volume (see [Perform a wand wave](https://vicon-help.atlassian.net/wiki/spaces/Tracker41/pages/14322153)).