function [I_n]=normalizar(I,a,b)
    max_v=max(max(I));
    min_v=min(min(I));
    den=max_v-min_v;
    if(den==0)
        I_n=I;
    else
        I_n=((I-min_v)/(max_v-min_v))*(b-a)+a;
    end
end