3a. Setup: Object Marking
What is Object Marking?
By marking the objects you wish to track on certain frames of your video, ABC Tracker is able to determine the size, visual appearance, quantity, and environment of objects to be tracked. Please mark objects carefully: these marks are used extensively throughout the tracking process.
How Many Frames Will be Marked?
Currently, ABC Tracker usually requests object markings on three frames.
How to Mark Objects
Set the Correct Brush Size
Set the brush size to cover the body of the objects, but as little image background as possible.
The brush size can be set using either:
- The scroll wheel on a mouse, or
- The "Brush Size" slider underneath the playback video
Tip
It is important to cover just the body of the objects, and not a large amount of the background image. To do this, it may be necessary to use the zoom features.
Mark Each Object
Mark the objects by clicking three times on each object: once on the object's head, once in the center of the object, and once on the object's tail.
While it does not matter whether the head or tail are selected first, the center of the object will need to be the second click.
How to Undo Object Marks
Undoing an Incomplete Mark
If a mark has not yet been completed (i.e. there are only 1 or 2 highlighted circles, and the third click has not been completed), right clicking with the mouse anywhere on the video area will remove the incomplete mark.
Undoing a Completed Mark
If a mark has been completed, right clicking with the mouse on the finished mark will remove only that single mark.
Questions on Object Marking
What if No Objects Exist in Frame?
If no objects exist in a frame, select the "No Objects Present" button
What if Object has an Abnormal Appearance in Frame?
Sometimes an object takes on an unusual appearance in a particular frame being marked, such as the object not marked here:
In these cases, it is still important to mark the object, approximating the head, middle, and tail of the object as well as possible.
Since ABC Tracker will later examine the video footage and track the object's appearance before and/or after the selected frame, the application will compensate for the object's unusual appearance in that specific frame.
The completed markings for the object above look like this:
