Change in images over time

Hi everyone! Im taking successive pictures of an hourglass. Then I take them to image J and create a stack, so when I press the “play” button, it looks like a movie… I want to have a resultant image that shows what is actually moving, that is, everything that may have changed between images turn into white and everything that haven’t changed turns into black. In that way, I may be able to show that the only thing that has moved between images was the sand (like a “motion contrast”). Can I do that using Image J?
Thank you very much!!!

hi @pauloric

You could subtract from image i the image i-1. The difference would be the sand which moved down. But you wont see the falling sand because it looks the same. Respectively it is hard to distinguish between two grains of sand which are falling because they look very similar and are very tiny.

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Use the image calculator (or calculator plus) function to calculate the differences between slices(z)=1 and slices(z)=x:

http://imagejdocu.tudor.lu/doku.php?id=gui:process:image_calculator

You can write a macro script to calculate all stack images in comparison to slices(z)=1.

Thank you guys!! I’ll try that and see if it works!