How to add filter just foreground and another filter to background?

Hello, i am trying to add filter to foreground and another filter to background:

I had an gray scale image which background is blur and foreground has an object. And i separated my image with iterative optimal threshold algorithm. Here is my code:

I=imread('a.png');
A=stdfilt(I);
T=1;
%%   G1 is foreground, G2 is background   %%
for i=1:16
G1=T>A;
G2=T<=A;
m1=mean(A(G1));
m2=mean(A(G2));
Tnew=(m1+m2)/2;
T=Tnew;
end

Here i am trying to add L filter to just foreground but it doesn't work.

L=[-1 -1 -1;-1 8 -1;-1 -1 -1];
P=imfilter(G1,L);
R=I+P;

And here i am trying to add Gfilter to just background but it also doesn't work.

G=1/16*[1 2 1;2 4 2;1 2 1];
J=imfilter(I(G2),G);
Result=J+R;

I know i am wrong somewhere but i also don't know how to fix it.

Answer 1

[yanqi liu]

clc; clear all; close all;
I=imread('rice.png');
A=stdfilt(I);
T=1;
% G1 is foreground, G2 is background   %%
for i=1:16
    G1=T>A;
    G2=T<=A;
    m1=mean(A(G1));
    m2=mean(A(G2));
    Tnew=(m1+m2)/2;
    T=Tnew;
end
figure; imshow(G1, []);

figure; imshow(G2, []);

G1 = I.*uint8(G1);
G2 = I.*uint8(G2);
figure; imshow(G1, []);

figure; imshow(G2, []);

% add L filter to just foreground
L=[-1 -1 -1;-1 8 -1;-1 -1 -1];
P=imfilter(G1,L);
R=I+P;
% add Gfilter to just background
G=1/16*[1 2 1;2 4 2;1 2 1];
J=imfilter(G2,G);
Result=J+R;
% imshow
figure; imshow(R, []);

figure; imshow(Result, []);