How to divide a closed detected edge of an image into 8 parts from a point inside in it..?

During my work course,I detcted the edge of the image. Now, I need to divide that closed edge detected image into equal parts from a point so that I can see which have greater area cointaing shaded edge portion .

[Image Analyst]

Don't you see a contradiction in your requirements? If the parts are equal how can one have greater area (except for digitization noise)? What do you mean by equal? Equal areas or equal angles? If the angles from the centroid are equal, then of course one sector might have a different area than another sector. Is that what you meant?

[KRISHNA TEJA DUDE]

yah..! I need the equal angles from centroid. So the below figure can have different areas corresponding to the parts as like cutting a pizza into equal parts from a point.

It would be helpful if u write a code for me.

Answer 1

[darova]

• use bwboundaries to get coordinates of a circle
• divide into equal parts

x(1:end/8)

Answer 2

[KRISHNA TEJA DUDE]

I got something for dividing a gray image into 8 parts from a point where i converted a rectangular matrix into square matrix

function [first,second,three,four,firstone,firstsecond,secondone,secondsecond,threeone,threetwo,fourone,fourtwo] = divide(image)

m =size(image,1); n = size(image,2);

for i = 1:m/2

for j = 1:n/2

first(i,j) = image(i,j);

end

end

figure(1),imshow(first)

for i = 1:m/2

for j = ((n/2)+1):n

secondd(i,j) = image(i,j);

end

end

second = secondd(1:m/2,((n/2)+1):n);

figure(2),imshow(second)

for i = (m/2+1):m

for j = 1:n

sample(i,j) = image(i,j);

end

end

threefour = sample((m/2+1):m,1:n);

row_s = size(threefour,1);

col_s = size(threefour,2);

for i = 1:row_s

for j = 1:col_s/2

three(i,j) = threefour(i,j);

end

end

figure(3),imshow(three)

for i = 1:row_s

for j = (col_s/2+1):col_s

fourth(i,j) = threefour(i,j);

end

end

four = fourth(1:row_s,(col_s/2+1):col_s);

figure(4),imshow(four)

firstone = triu(first);

figure(5),imshow(firstone)

firstsecond = tril(first);

figure(6),imshow(firstsecond)

second2 = flipdim(second,2);

secondone = triu(second2);

figure(7),imshow(secondone)

secondsecond = tril(second2);

figure(8),imshow(secondsecond)

third = flipdim(three,1);

threeone = triu(third);

figure(9),imshow(threeone)

threetwo = tril(third);

figure(10),imshow(threetwo)

fourone = triu(four);

figure(11),imshow(fourone)

fourtwo = tril(four);

figure(12),imshow(fourtwo)

Answer 3

[Image Analyst]

See the FAQ: https://matlab.fandom.com/wiki/FAQ#How_do_I_create_an_arc.3F

Adapt as needed.