Point Tracking

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Point Tracking

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Navigation:  Widget Designer > Devices > AirScan >

Point Tracking

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This chapter explains the Point Tracking settings in the AirScan Tool in Widget Designer. For more information please see the introductory chapter.

Almost all settings in this section can be scripted using the available "WDAirScan..." commands.



Enter here the amount of points that should be detected and provided for further processing.

Point ID Offset:

The Point ID Offset should be used when you are sending the multi-touch data from this AirScan via the Remote Input to another Widget Designer. It avoids that the multi-touch points from several data inputs get the same IDs causing ID conflicts.


Trim allows to minimize errors on Point enter, with this value a number of scans will be ignored until the point motion processing is activated. The default value for Trim is 0.

VCount (Validation Count):

The Validation Count defines the amount of rays that have to be interrupted in order to validate a touch point. The default value is 2.


The default value for the Gap is 5. This means that within 5 rays distance of a detected point all other interrupts will be discarded.

Max Delta:

The default value for Max Delta is 100. The Max Delta function determines the maximum speed for Multi touch Point Tracking.

X and Y Offset:

These offsets allow to run the Widget Designer on a secondary screen. If you're doing so please enter here the pixel offset for x and y.
Example: resolution of primary and secondary screen is 1024x768, WD runs on the secondary screen, enter x=1025 and y=0.

Start (Ray):

The AirScan sends out 500 Rays over 180° clockwise. If you want to discard a certain amount of rays up from the start, enter the new value here (0-499).

Stop (Ray):

The AirScan sends out 500 Rays over 180° clockwise. If you want to discard a certain amount of rays before the actual end, enter the new value here (0-499).

Range: (Touch point offset):

The touch point offset for the Multi-Point mode allows running the WD on a secondary screen.

Motion Prediction and Factor:

In addition to the options to damp the incoming data, you can also predict its motion. First, enable the "Motion Prediction" then set the factor. With a higher factor you can reduce the latency that occurs when the tracked points move quite fast. However, sudden movements should be avoided then. For example, if your prediction value is very high and the movement stops suddenly, WD "overshoots" as the movement before the stop is predicted to also happen in the future. Hence, the motion prediction must be fine-tuned to achieve a good compromise between latency and overshooting. In addition, it is important to set up a good damping value in subsequent nodes. For example, with no damping, there is quite some noise and this jittering movement is of course also predicted which results in more jitter.


In order to output multi-touch data to other applications this option allows to send the AirScan's multi-touch data via the open source protocol TUIO.

This protocol is widely used around the world by many application developers and is a commonly known way to transmit the individual touches.
To use AirScan with TUIO, set up the TUIO host IP and Port in the Connection Manager.


Enable the "Info" check box to show the Point Read-Out Dialog with the data of all 24 multi-touch points.

click to enlarge

Generally the first ray interrupt will be displayed as P1, second one as P2 and so on.
Each point will be tracked until it is removed out of the AirScan Field. So if there are P1 and P2 detected and P1 is removed, P2 stays P2 and does not changes its ID to be P1.

Point Active (true or false):

A point turns active as soon as there is a ray interrupt started inside the Active Region of the AirScan.
As long as the interrupt stays within the Safe Region, the point stays active.
If the interrupt started out of the Active Region or if there is no interrupt, the Point's status turns to False.

Point Enter:

If there is an interrupt detected inside the Safe Region (whether it is active or not), the value for the X & Y position of a Point where it entered the AirScan field will be displayed here.

Point Move:

As long as the value for Point Enter is true (1), the X and Y position of this Point will be displayed here.

Point Leave:

The last valid X & Y position of a Point while leaving the AirScan field will be displayed here.

To use this point read-out for further processing, please use the AirScan Multi-Point Input Node.

The next chapter explains the settings for Mouse Control.