Planar Tracking

• Planar tracking is a technique used for tracking the movement and transformation of flat or planar surfaces within a video or image sequence. Unlike point tracking, which tracks individual points in an image, planar tracking focuses on tracking the entire planar surface, making it particularly useful for tracking objects with consistent textures or patterns.

Here’s how planar tracking can be done in Nuke:

Asset Gather:

1. Selection of Planar Surface:
   • Identify the planar surface in the footage that you want to track. This surface should have distinguishable features or patterns that the tracking algorithm can follow.
2. Adding a Tracker:
   • Use a planar tracker node (such as the “Tracker” node in Nuke) to add a tracker to the selected planar surface. This involves defining the region on the first frame and indicating the planar area to be tracked.

1. Automatic Tracking:
   • The planar tracker analyzes the selected features within the defined region and automatically tracks their movement across subsequent frames. This is beneficial for surfaces with consistent textures, making planar tracking robust and reliable.
2. Adjustments and Refinement:
   • After the automatic tracking, you can review and make manual adjustments if needed. This allows you to refine the tracking by correcting any drift or errors that may have occurred during the automatic tracking process.

1. Transformation Data:
   • The planar tracker provides transformation data, including position, scale, rotation, and skew, for each frame. This data can then be applied to other elements, such as graphics or effects, to ensure they match the movement and perspective changes of the tracked planar surface.
2. Integration into Compositing:
   • Once the planar tracking is complete, you can integrate other elements into the scene, and they will follow the tracked planar surface’s movement. This is particularly useful for tasks like adding labels to moving objects or seamlessly integrating CGI elements into live-action footage.

• We may encounter issues with foreground elements, such as the light pole in this image. However, we can easily overcome these challenges by utilizing the same tracking data to apply rotoscoping. The resulting roto alpha can then be used as a clipping mask to bring the pole to the foreground.