How can I display an image with a fixed display flickering rate?

[barana]

Hi all,

I want to display an image with a fixed flickering rate in front panel, for example 20 Hz.

How can I do that.

Thanks.

[P@Anand]

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@baranaseman wrote:

Hi all,

I want to display an image with a fixed flickering rate in front panel, for example 20 Hz.

How can I do that.

Thanks.

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You want to display single image or multiple images at a frame rate of 20Hz?.

[altenbach]

Define "flicker". I guess you want to toggle between two states, (1) the image, (2) somethings else (no image, solid white, solid black, etc).

The first problem is that front panel updates are typically asynchronous, so as a first step you need to set your indicator to "synchronous display". Then you need to make sure that the image can actually be updated at the desired rate.

Can you show us a simplified version of your VI with the image? How accurate does the rate need to be?

[barana]

I want to display single image at a frame rate of 20 Hz.

[P@Anand]

Still you are not clear with your question. When say single image at 20Hz it doesn't make sense. As altenbach said you want to switch beween a solid background and the image at 20Hz?

[altenbach]

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@barana wrote:

I want to display single image at a frame rate of 20 Hz.

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That makes no sense. Why does it need to be refresehed if it does not change?

If you want to set the monitor refresh rate, that would a an OS/graphics driver issues and LabVIEW has no control over it. I doubt most hardware will support 20Hz.

[barana]

I just want to display an image to the user that flickers at 20 Hz refresh rate. Something just like the monitor refresh rate. As you know, the monitor screen refresh rate is normally 60 Hz. My image should blink 20 times per second (20 Hz).

[barana]

I am studying brain waves for my project. When a user is looking at a blinking image with a defined flickering frequency, some changes happen in his brain waves, and I want to process it. So for the first step, I should display an flickering image to him.

[barana]

Thank you P@Anand and altenbach,

Now it is more clear for me. I thought that there is a block in Labview for controling image flickering rate. So I should switch between my image and a solid background, e.g. solid black.

But I don't know about synchronous and asynchronous display in Labview. Whould you please explain it more for me?

[P@Anand]

Here is a basic example to display image and make it flicker. Use it and try to improve to get the exact frame rate you want.

Remember this is not the actual solution, its just to give you an idea.