Hough transformation

Hi! I have a problem with the function houghlines : it returns me an empty struct 1x1. Moreover : do you know how to transform the struct in a list of equations of the lines ?? Thank you very much

imm = [0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0, 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0, 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0, 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0, 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0, 0 0 0 0 1 1 0 0 0 1 1 1 0 0 0 0, 1 1 1 1 0 0 1 1 1 0 0 0 1 1 1 1, 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0, 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0, 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0, 0 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0, 0 0 0 0 0 0 0 0 1 0 0 1 1 1 0 0, 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 1, 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0, 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0, 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0];

   imshow (imm);
   [H, THETA, RHO] = hough(imm);
   picchi = houghpeaks(H,50

   linee = houghlines(imm, THETA, RHO, picchi);