SHINE toolbox, problmes with sfPlot

Hi everyone!

I am trying to extrac the power of frequency bands from the sfPlot found in SHINE toolbox so that I can make comparissons across a set of images. Intially I am trying to use the sfPlot function but it seems that it doenst work. Whatever impout I give in the function eg. sfPlot('12345'), or even the name of an image in the input folder eg. sfPlot('b1.tif') it gives me the same response:

    Empty matrix: 0-by-1

and a window pops up but with no graph. Do you have any idea how to go about and solve this problem?