Change in no of pixels

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Raghavan Raghavan
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Change in no of pixels


Hi, William,

While saving the images from PIVlab, the no of pixels (image dimension) is getting downgraded. The issue is: the no of pixels in the final output is changing from time to time though not frequently. could you please let me know if there is a way to control the no of pixels in the output images  ?

Thanks,
Raghavan
William William
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Re: Change in no of pixels

Hi,
Matlabs figure export sucks, so a workaround is used that works a bit like a screenshot. So the output size depends on the size of the Pivlab program window. You can however increase the resolution a lot by entering e.g. "2" in the image scale dialog that pops up when you try to save an image from Pivlab.

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.

Raghavan Raghavan
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Re: Change in no of pixels


Hello William,

Thanks for your reply. I realized that the resolution is changing based on the size of the PIVlab window. However I am not getting how I can enter value for the image scale. The pop up for saving image does not ask details for image scale. There is only a space for controlling the fps.

Meanwhile from your reply, I understand that the velocities are computed with the actual resolution (pixel no) of the images right ? Please correct me if I am wrong. Because, until now, since I found that the resolution is decreased (approximately by a factor of 2) while the images are saved, I was adding up these pixels (for my analyses) to compensate for the actual resolution of the raw data.

Thanks,
Raghavan
William William
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Re: Change in no of pixels

Hi, the dialogue will only pop up if you save as bmp or jpg. You can generate a movie file from these picture series outside Matlab. The scale of the output images is "random", but the velocity calculations are correct and will always be based on the real scale of your input images.

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.

Raghavan Raghavan
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Re: Change in no of pixels

Thank you very much !