Multilayer region growing algorithm not working

Hi,

I am trying to implement the multilayer topographic region growing algorithm for breast tumor segmentation. TM 250.jpg is the original image. Unfortunately, I am getting a complete black image as shown in the figure r.jpg below. Any suggestions would be appreciated.

I= rgb2gray((imread('TM250.jpg')));
x=64; y=64;
J=regiongrowing_MLT(I,x,y,0.5);
imshowpair(I,J,'montage')