Vectors larger than interrogation area

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Chris Chris
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Vectors larger than interrogation area

Hi,

Forgive me if this is a very basic question and should be directed elsewhere.

I have begun using PIVlab (and have enjoyed it a lot - nice tool) to analyse images of labelled proteins within cells.  The proteins I am interested in attach to the ends of dynamic structures called microtubules and move around continually.  Without being able to track them individually (I've tried with other software), I turned to PIV as an alternative.

My problem is that when I get the result from the analysis, there are a few vectors (depending on the settings) that are extremely large, and to me it is not clear how they get there, because they are larger than the interrogation window.  My (quite limited) understanding of PIV is that the interrogation window sizes define which parts of the image are compared with each other, and thus should surely limit the sizes of vectors to the size of the largest interrogation window.  Or is this incorrect?

Any help will be greatly appreciated.

Thanks a lot,
Chris
William William
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Re: Vectors larger than interrogation area

Hi Chris,
the vectors are not displayed at scale. The real velocities are just proportional to the length of the vectors. Click on a vector to see the real velocity (displayed at the lower right).
Cheers,
William

-- Dr. William Thielicke
http://William.Thielicke.org

Please consider donating for the PIVlab project:
http://paypal.me/pools/c/81Y8wBVi4y

The developer needs to update to a recent Matlab release in order to keep the project running.

Chris Chris
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Re: Vectors larger than interrogation area

Hi William,

Thanks very much for your help - I didn't consider scaling.

Cheers,
Chris