3D Compositing with Action > Action: Analyzer >
Camera Tracking

You can perform automatic 3D tracking based on the camera properties of the device used to acquire the image sequence you want to track. You can specify these properties, or let the analyzer automatically detect the best solutions for the analysis. Even if you want to perform object tracking on specific moving areas of the scene, you also start with an analysis using camera tracking to create a properly tracked camera.

To create a 3D camera track:

1. Add an Analyzer Mono or Analyzer Stereo node, as explained in Adding an Analyzer Node.
2. Set Analysis options. For example, decide if you need to use a matte or GMask in the analysis. In an image sequence of a busy street, you can create a matte or mask of moving elements (such as cars and people) to isolate this area from the analysis. See Analysis Settings for details of each Lens Correction, Constraints, and Camera setting.
3. Enable Forward & Backward to track the image sequence backward after the forward tracking has completed. This option takes longer, but you may get better results.
4. If needed, adjust the size and number of trackers.

   Smaller trackers can speed up the calculation, while larger trackers make the analysis more robust with regard to image noise and variations. A general rule is to increase the size of the trackers when tracking high-resolution footage (2K or larger) that contains more noise.

5. Click Track.

   You can see a progress indicator beside the Track button. You can interrupt the analysis and resume it by clicking Track again. Most of the time, tracking occurs in the background, allowing you to continue working while tracking. In Batch, you can use connected input and matte clips as the media to be tracked. In this case, tracking becomes a foreground process.

   After tracking has completed and you press Confirm, the Track button changes to Calibrate, and you can see the 2D tracks (the blue squares in the following example) and 3D points (green crosses) in your image, provided that you are in Analyzer 3D view.

   Image courtesy of Behavior Communications Inc.

   The FBX camera connected to the analyzer node synchronizes to the results of your 3D tracking, and any further changes you make to the 3D track are reflected in this camera.

6. If you are satisfied with the results of the tracking analysis, proceed to Converting the Camera Analyzer Results. If you want to tweak your track results, see Fine Tuning the Analysis.

#### Topics in this section

- Analysis Settings
- Fine Tuning the Analysis
- Converting the Camera Analyzer Results