Track mode (basics)

Usage examples:

• Create new annotations for a sequence of frames.
• Add/modify/delete objects for existing annotations.
• Edit tracks, merge several rectangles into one track.

1. Like in the Shape mode, you need to select a Rectangle on the sidebar, in the appearing form, select the desired Label and the Drawing method.

   

2. Creating a track for an object (look at the selected car as an example):

   • Create a Rectangle in Track mode by clicking on Track.

     

   • In Track mode the rectangle will be automatically interpolated on the next frames.

   • The cyclist starts moving on frame #2270. Let’s mark the frame as a key frame. You can press K for that or click the star button (see the screenshot below).

     

   • If the object starts to change its position, you need to modify the rectangle where it happens. It isn’t necessary to change the rectangle on each frame, simply update several keyframes and the frames between them will be interpolated automatically.

   • Let’s jump 30 frames forward and adjust the boundaries of the object. See an example below:

     

   • After that the rectangle of the object will be changed automatically on frames 2270 to 2300:

     

3. When the annotated object disappears or becomes too small, you need to finish the track. You have to choose Outside Property, shortcut O.

   

4. If the object isn’t visible on a couple of frames and then appears again, you can use the Merge feature to merge several individual tracks into one.

   

   • Create tracks for moments when the cyclist is visible:

     

   • Click Merge button or press key M and click on any rectangle of the first track and on any rectangle of the second track and so on:

     

   • Click Merge button or press M to apply changes.

     

   • The final annotated sequence of frames in Interpolation mode can look like the clip below:

     

     Read more in the section track mode (advanced).