Individual Pixel standard Deviation from Stack?

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Individual Pixel standard Deviation from Stack?

Duff_Howell
I am looking at high speed EMCCD cameras and trying to study the background noisiness of the cameras.

I have multiple individual snapshots of the camera output (1K x 1K TIFF images), for various gain and exposure times, with multiple shots, for statistical validity, of each gain/exposure combo.

What I want to determine is, for each pixel in the camera, is both the mean, over the multiple exposures, and the standard deviation about that mean, across multiple exposures, for each pixel. I'm a newbie to the image calculator and image math functions. I've been able to:

Import the images into a stack, using
     File > Import > Import > Image Sequence  
for a folder with the multiple time repeats of a given gain and exposure

Get an average, for each pixel, over all the images in the stack, using
                  Process > Image Calculator > Process

With some saving of the results, I could get the sigma squared by calculating the square of the images, and subtracting the square of the mean... but when I use
           Process > Math > Square
the result is a pure white image, for each slice, maxxed out at 64K.

Converting to a 32 bit image likewise adds decimal places, but no greater upper range for the numbers for the middle of the calculation.

Is there a way of pulling out the individual pixel sigmas about the means, or am I going to need to slog through making an outside array that doesn't think it's an image? I have an application with very small, often single-pixel, fluorescent dots, with only single-time imaging, and it's critical to inderstand how much the background at any given pixel can fluctuate for a single-instance measurement.

To be clear, I'm not looking for the histogram numbers for a ROI in a given image, or the average of many images, I'm looking for, in essence, the single pixel histogram across the images in a stack, with the histogram mean and sigma to be extracted.  Is this doable, or are there perhaps examples within the example library that I can further educate myself upon?

Thanks!