Conversion raster data according to X,Y histogram axis to apply FWHM

I have a raster data for which I generated a histogram using histogram function. Now I would like to use the information from the histogram (from X,Y axis) to generate full width half maximum ( FWHM ). How to specify variables which will represent the information from my X,Y axis?

Answer 1

[Walter Roberson]

Why do it that way?

I show some FWHM code in http://uk.mathworks.com/matlabcentral/answers/225685#comment_295936 that works directly on the array of data.