%Frost?filter?for?speckle?noise?reduction
%Author?:?Jeny?Rajan
function?[ft]=frost（I）
%?I?is?the?noisy?input?image
tic
[x?y?z]=size（I）;
I=double（I）;
K=1;
N=I;
for?i=1:x
????for?j=1:y??????????????????????????????
????????if?（i>1?&?i1?&?j????????????mat（1）=I（i-1j）;
????????????mat（2）=I（i+1j）;
????????????mat（3）=I（ij-1）;
????????????mat（4）=I（ij+1）;
????????????d（1）=sqrt（（i-（i-1））^2）;
????????????d（2）=sqrt（（i-（i+1））^2）;
????????????d（3）=sqrt（（j-（j-1）