How to apply Bounding BOX for selected objects

Connectivity helps in applying bounding box for selected objects.

Calculate  :

i)Area 

ii) Mean 

iii)Centroid 

iv) Perimeter

clear

close all;

I=imread('coins.png');

figure,imshow(I);

B=im2bw(I);

figure,imshow(B);

c=imfill(B,'holes');                            % Fill the holes

figure,imshow(c);

[label,num]=bwlabel(c);

display(num)

object=3;                                       % To apply bounding box for labelled 3

[row,col]=find(label==object); % to find coordinates of the bounding box

sx=min(col)-0.5;

sy=min(row)-0.5;

breadth=max(col)-min(col)+1;

len=max(row)-min(row)+1;

bbox=[sx sy breadth len];

display(bbox);

figure,imshow(I);

hold on;

x=zeros([1 5]);

y=zeros([1 5]);

x(:)=bbox(1);

y(:)=bbox(2);

x(2:3)=bbox(1)+bbox(3);

y(3:4)=bbox(2)+bbox(4);

plot(x,y);

obj_area=numel(row);

display(obj_area);

% Find Centroid

X=mean(col);

Y=mean(row);

Centroid=[X Y];

display(Centroid);

plot(X,Y,'o','color','r');

hold off

%Find perimeter

BW=bwboundaries(label==object);

figure, imshow(I);

hold on

visboundaries(BW);

c=cell2mat(BW(1));

perimeter=0;

for i=1:size(c,1)-1

perimeter=perimeter+sqrt((c(i,1)-c(i+1,1)^2+c(i+1,2)).^2);

end

display(perimeter);

% calculation with regionprops for verification purpose

sdata=regionprops(label,'all'); % click on sdata and check for different parameters

RESULT:

Fig 1

Fig 2