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Can an Autotracker template be saved? post and replies

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Can an Autotracker template be saved?
Eric Erpelding
2 Posts

Tracker is an amazing tool.

We are using it to track a laser dot that is projected above a meter stick in order to record the motion of a torsion beam.

The laser dot is more like a disk with a yellow center and red circular boundary.

It is somewhat of an art to create an Autotracker template that will track the laser disk without some resulting "slippage". When the center of the disk moves we want Tracker to detect that movement.

Once a good template is made that results in a tight track of the laser disk image, we would like to save it in the project file.

Is this possible?


Replies to Can an Autotracker template be saved?

Re: Can an Autotracker template be saved? -
Douglas Brown Avatar
Douglas Brown
339 Posts

Sorry, there is no way to save a template.  But it's an interesting idea and might not be too hard to implement.

A laser spot is a really interesting thing to track! Lots of potential there. Can you say more about how you make a good template and how you use it? For example, do you turn the evolution rate down to 0%?  Do you look ahead?  Is it the shape and/or size of the template critical? Is the outer edge of the template in the yellow zone or does it include some surface background? Do you apply any filters to the video to enhance the difference between the yellow and red?



> Re: Can an Autotracker template be saved?
>
> Tracker is an amazing tool.
>
> We are using it to track
> a laser dot that is projected above a meter stick
> in order to record the motion of a torsion beam.
>
>
> The laser dot is more like a disk with a yellow
> center and red circular boundary.
>
> It is somewhat
> of an art to create an Autotracker template that will
> track the laser disk without some resulting "slippage".
> When the center of the disk moves we want Tracker
> to detect that movement.
>
> Once a good template is
> made that results in a tight track of the laser disk
> image, we would like to save it in the project file
>
>
> Is this possible?



Re: Can an Autotracker template be saved? -
Eric Erpelding
2 Posts

Hi Douglas, thank you for your reply.

I found a way to document the template. I simply use a screen capture program such as PicPick to capture an image of the Autotrack template and then save the image as a supplemental file in the Tracker project.

I have only been using Tracker a short while to track a laser spot. It is indeed an interesting thing to track because the laser spot can change its colors as it moves back and forth! Sometimes it has a definite center portion that is yellow or white surrounded by a reddish annular band, sometimes the spot is completely red with some slight yellowish hue in the center, almost looking like a small sun.

The spot is projected against a solid grey or black background so the contrast is already good.
I have not applied any filters to the video.

For some of the earlier laser tracks, I did set the evolution rate to zero, but I found that as the spot moved back and forth the image would change slightly, so for the latest Track I set the evolution rate to 10%, and it seemed to work well.

I have not used the Look Ahead feature yet.

The size and shape of the template are critical to getting a responsive tight track.
To get a good track I found including some of the grey or black surface background is important, but not too much.

I try to keep the search area rather close to the outer portion of the laser spot.

Attached is an image showing the Autotrack template used for a recently made Laser Track test.

Attached File: AutotrackTemplate.png



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