Re: Overlaying thousands of images with transparent backgrounds

Posted by Michael Schmid on Feb 24, 2016; 4:30pm
URL: http://imagej.273.s1.nabble.com/Overlaying-thousands-of-images-with-transparent-backgrounds-tp5015705p5015706.html

Hi Jennifer,

if you don't have NaNs but a stack of binary images, you can use Image>Stacks>Z Project.
If the particle has a pixel value of 0 (black) and the background is 255, the minimum of all stack slices will be black in all positions where you have a particle in any slice.
If the particle has a pixel value of 255 (white) and the background is 0, the maximum of all stack slices will be white at positions where the particle has passed.
With background value=0 and a nonzero value for the particle, you can also use the sum of all slices. The positions where the particle is in more than one stack slice will become brighter.

  http://rsb.info.nih.gov/ij/docs/guide/146-28.html#toc-Subsubsection-28.6.11

Michael
________________________________________________________________
On Feb 24, 2016, at 16:15, XBYJ wrote:

> Hi everyone.
>
> I have thousands of images, showing the progression of a falling particle in
> slow motion, which I need to combine into a single image to create a visual
> track of the particle's progression.
>
> I have used an ImageJ macro to batch-convert the images to binary (the
> particle is black, the background is white). I have then converted the
> binary images to 32-bit TIFF and set v=0 to NaN. So for each image, the
> particle has a value of 255 and the background has a value of NaN.
>
> How would I then overlay all the images so that the particles are black and
> the background NaN values are white?
>
> Thank you so much for any help.

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