Category: Diagnostic Imaging
Author’s Name: David Platten,
Published: May 20, 2013
ImageJ plugin to calculate a variance or signal-to-noise map of a digital x-ray image.
The routine will run on a user-selected rectangular region of interest (ROI). If no ROI is selected then the whole image is selected and analysed.
ImageJ plugin to calculate a variance or signal-to-noise map of a digital x-ray image.
The routine will run on a user-selected rectangular region of interest (ROI). If no ROI is selected then the whole image is selected and analysed.
It breaks the large ROI into smaller square ROIs, and calculates the chosen statistical parameter for each region. The user is asked to supply the side-length of the smaller ROIs (in mm).
The routine calculates variance as:
sum[x – mean(x)] / n
The routine calculates standard deviation as:
sqrt(variance)
The routine calculates signal-to-noise as:
mean(x) / standard deviation(x)