Troubleshooting Manual Tracks
Even with manually positioned tracks, some sequences are inevitably going to cause problems. There are a number of pre-tracking checks you can perform to assist C_Tracker:
• Play through the sequence before placing your tracking anchors.
• Look for features that are consistent throughout the majority of the sequence.
• Avoid occluded features where possible - see Dealing with Occlusions.
Tip: You can also add auto-tracks to improve the result further. See Automatic Tracking for more information.
To troubleshoot manual tracks:
1. | First, turn on the color-coded error indicator by clicking the traffic light Viewer tool . |
Each keyframe is colored on a sliding scale from green (good match) to red (poor match).
A red keyframe doesn’t necessarily mean that the tracking result is poor, only that C_Tracker couldn’t reliably match the pattern from one keyframe to the next.
2. | Move the tracking anchor to the first of the poor frames, just about the center of the image in the example. |
3. | Using the zoom window, drag the anchor to the correct location of the grabbed pattern. |
4. | Advance the playhead to the next poor keyframe and repeat until the track is complete. |
When you're happy with the number and distribution of tracked features, you can solve the camera and then use the results for stabilizing or match-moving. See Solving Cameras for more information.
Dealing with Occlusions
C_Tracker’s offset capability allows you track an obscured feature using the relative position of another feature, providing that the distance between the two points remains constant.
1. | Track the pattern normally until the occlusion causes Tracker to fail. |
The zoom window helps to identify the failure point.
2. | Play though the sequence to identify a likely offset point - a pattern that remains equidistant from the original pattern grab. |
3. | Hold down Ctrl/Cmd and drag the tracking anchor to the offset position. |
The offset amount is recorded in the Tracks list and highlighted in yellow in the Viewer.
4. | Continue tracking as normal by clicking the track backward (Z) or forward (V) button. |
Tracker combines the two tracks into a single continuous track.
5. | Use the clear backward and forward buttons to clear poor keyframes. Click clear all to remove all keyframes. |
Note: You can reset tracking anchor pattern and search areas by clicking .