Setting key point parameterssettingkey point parameterskey pointssetting the parameters

By default each key point has a pattern size, search zone and quality threshold, as defined in 2D Tracking page of the User Preferences window. See Configuring the tracker.

These parameters are global and apply to all key points, however it is possible to set the parameters for each key point separately. In most cases the default values are sufficient to complete a successful track, but you may want to set them.

Setting the parameters of a single key point

To set the parameters of a single key point:

Select the point to edit.
In the Parameters Window, the Current time text field shows the current time.
Refer to the following list for parameters details:
- The horizontal point position X in pixels in the image (if the point is a key, you can modify its position. The origin is the upper left corner of the image).
- The vertical point position Y in pixels in the image.
- Status shows the type of key. Select a new key type from Begin, End, Intermediate, and Single from the drop-down list.
- Threshold is the minimum accuracy of the similarity between two pixels. A value too low causes the tracker to match any pixels. A value too high causes the tracker to stop or to place too many automatic keys.
- Pattern Zone is the area to search for in the adjacent image. You can use different values for the different sides. For example, if you track a point within an area of uniform color, the tracker may have problems to follow the point. Increase the template area to include pixels of a different brightness to eliminate this problem.
- Search Zone is the area in which to search, in the adjacent image. You can use different values for the different sides. If you see that the point moves a lot through the sequence, make the search area larger, remembering that a larger search size decreases the tracking speed.

The tracker uses these parameters to find the corresponding point in the adjacent image and track the point and the information is updated if you change the current time.

NoteIf the selected point is not a key point, but has been calculated by the tracking process, then you can only read the track point information in the 2D page.

Parameters at time shows the current time.
X shows the horizontal pixel position of the point in the image. The origin is the upper left corner of the image.
Y shows the vertical pixel position of the point in the image. The origin is the upper left corner of the image.
Tracking Score shows the estimated precision quality of the tracking.
Status shows the type of tracking used to calculate this point. The status can be Forward, Backward or Bidirectional.

Color Tracking

All key points have a separate color tracking setting. For example, a red cross on green background may ignore blue channel.

Gray. Track using luminance information (an average of the R,G,B colors). This is the default option.
Color. Track using all color components independently.
Coeff. Track using a coefficient for each color channel. For example, when a color seems to be too “noisy”, just lower its coefficient. If the coefficient is 0, then the color is ignored.
Auto. Track using a coefficient for each color channel, but coefficient is computed automatically. MatchMover analyzes the image to find the best coefficient.