seperation of Background and Object in an color image

Hello drs.. I had code to determine the boundary pixels of an image below

clc; % Clear command window. clear; % Delete all variables. %%

close all; % Close all figure windows except those created by imtool.

%% Read image

I = imread('C:\Users\admin\Downloads\shadow.jpg'); figure, imshow(I),title('Original image'); imtool(I); [h w d] = size(I);

%% Top boundary

for j =1:w Tr(j) = I(1,j,1); Tg(j) = I(1,j,2); Tb(j) = I(1,j,3); end

%% Left boundary

for j =1:h Lr(j) = I(j,1,1); Lg(j) = I(j,1,2); Lb(j) = I(j,1,3); end

%% Right boundary

for j =1:h Rr(j) = I(j,255,1); Rg(j) = I(j,255,2); Rb(j) = I(j,255,3); end

%% Bottam boundary

for j =1:w Br(j) = I(255,j,1); Bg(j) = I(255,j,2); Bb(j) = I(255,j,3); end

I need check the colors in pixels with other pixels in the image and need to eliminate the same colors to get the background and object seperately