Blob Tracking

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Calibration/Blob Tracking

Tracks blobs over time. ​


The Blob Tracking box tracks blobs over time to discriminate continuous points from new points. In the process, the box discards small position changes within a defined area. The box outputs the active blob ID and position.

General Use Case: The Blob Tracking box is useful to keep track of positions on a multi-touch detection device.


Points 2D Points, Float2 Vector Receives the points to process.


Data View 2D Render Target Outputs a texture showing visually the information of the box. The texture purpose is to show where blobs are detected.
IDs Int Vector Outputs a vector of Int sorted in ascending order. Active when the Output Type is set to Points.
Pointers Pointer Event Vector Outputs the mouse event generated by the blob. Active when the Output Type is set to Pointer Event.
Points 2D Points Outputs a vector of points in the same order as the vector of IDs. Active when the Output Type is set to Points.



Maximum Track Distance Float Sets the maximum distance from the blob center to be considered within the same blob. The distance applies between positions and from frame to frame.
Maximum Track Distance Unit String Sets the distance unit for the Maximun Track Distance parameter. The absolute leave the inputed data unchanged, usualy in pixels unit. The Relative use a axis as base to normalized the distance unit.
Relative Axis String Sets the Relative Axis used as base to normalize the unit. The length of the selected Relative Axis has a value of 1.0.
World Margins Float Sets the margins of the screen.
Enable Smoothing Toggle Enables the smoothing of the outputted blob positions.
Smoothing Quantity Float Sets the level of smoothing for the outputted positions. A low level keeps the inputted position unchanged while a high value may intefere with the blob detection.


Maximum Blob Count Int Sets the maximal number of blobs alive.
New Input Confirmation Delay Animation Time Sets the minimal required time of stability for a position to be as considered a blob.


Show Inactive Blobs Toggle Outputs coordinates of the active and inactive blobs.
Enable Inactivity Timeout Toggle Enables the inactivity timeout.
Inactivity Timeout Animation Time Sets the time before an inactive blob is remove from the list. Inactive blob are then considered alive till their death and can be reactivated by the blob tracker.
Friction on Inactive Float Sets the friction added to the movement of inactives blobs.


Output Type String Select the type of data outputted between Points and Pointer Event.
Output Down Event Toggle Outputs Down Event in the Pointers output when enabled.
Output Move Event Toggle Outputs Move Event in the Pointers output when enabled.
Output Up Event Toggle Outputs Up Event in the Pointers output when enabled.
Output Press Event Toggle Outputs Press Event in the Pointers output when enabled.
Press Mode String Chooses between mouse Button and Drag-And-Drop behavior.
Press Radius Threshold Float Sets the size if the zone where a position is considered pressed.
Press Confirmation Time Animation Time Sets the required time to hold the position before triggering a mouse left click event.
Enable Output Pin : Data View Toggle Enables the Data View Output Pin.

See Also

Boxes related

Blob Detection, Polar Keystone, SICK, Pointer Device, TUIO Receive, Point Mapping, Point Simulator, ​​

Version Information

Current documentation version: 2.1.3. ​ ​