Circle packed with Circles
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carlas
el 23 de Dic. de 2011
Comentada: Image Analyst
el 17 de En. de 2020
Dear all,
I am wondering how to generate a circle filled with smaller circles? Do I have to calculate all the circle centers or is there a general way how do this numerically? I have the Image Processing Toolbox.
Kind regards,
Carlas Smith
1 comentario
Respuesta aceptada
Chandra Kurniawan
el 24 de Dic. de 2011
Here the code :
First, you need to create a m-file
function [X Y] = circle(center,radius,n)
THETA = linspace(0, 2 * pi, n);
RHO = ones(1, n) * radius;
[X Y] = pol2cart(THETA, RHO);
X = X + center(1);
Y = Y + center(2);
Save this code with filename 'circle.m'
Then create a new m-file
function circles(R);
axis([0 2*R 0 2*R]); axis off; grid off; hold on;
[xoc yoc] = circle([R R], R, 1000); % outer circle
plot(xoc, yoc, '-','linewidth',2,'color',0.5.*rand(1,3));
[xcc ycc] = circle([R R], 1, 1000); % center circle
plot(xcc, ycc, '-','linewidth',2,'color',0.5.*rand(1,3));
numlapis = ((2*R) - (R+1)) / 2;
for cnt1 = 1 : numlapis
lapis(cnt1) = cnt1 * 6;
[xcoor ycoor] = circle([R R], cnt1*2, lapis(cnt1)+1);
for cnt2 = 1 : lapis(cnt1)
[xc yc] = circle([xcoor(cnt2) ycoor(cnt2)], 1, 1000);
plot(xc, yc, '-','linewidth',2,'color',0.5.*rand(1,3));
end
end
Save this code with filename 'circles.m'
And about how to use it.
After you save the files, you can call it from command window.
Just type 'circles(any diameter)'
Eq : circles(5);
Note that this function works well with odd number.
Just try :)
3 comentarios
Sonal Gahlawat
el 16 de En. de 2020
Thank you for this code.
I tried using this code and it works great. However, when I change the radius of the inner circle, it doesn't work. Either the small circles become sparse or overlap if I decrease or increase the radius, respectively.
I would really appreciate any help.
Image Analyst
el 17 de En. de 2020
Show your code and error (or why it didn't work), a screenshot (if one was created), and say or show what you were expecting.
Más respuestas (4)
Chandra Kurniawan
el 23 de Dic. de 2011
Hello,
Did you meant??
With diameter = 3
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/167741/image.jpeg)
Or with diameter = 5
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/167742/image.jpeg)
Or with diameter = 7
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/167743/image.jpeg)
Or any diameter
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/167745/image.jpeg)
7 comentarios
Pooja Kolati
el 21 de Feb. de 2016
Editada: Pooja Kolati
el 21 de Feb. de 2016
thank you! But it is still not helping me for packing even number of circles.
Image Analyst
el 21 de Feb. de 2016
Did you write any code using the FAQ at all?
You forgot to post it.
Junaid
el 23 de Dic. de 2011
Dear Carlas,
The easy way is to use this link. http://www.mathworks.com/matlabcentral/fileexchange/2876-draw-a-circle/content/circle.m
save circle.m in your working directory. Then give input. In example below I will draw three circles.
circle([50,50],15,1000,':');hold on;
circle([50,50],10,1000,':');
circle([50,50],5,1000,':');
If I keep the center same and just change the radius of the circle, we can easily make circle inside the circles.
I hope I understand you well. let me know about this if worked.
3 comentarios
Image Analyst
el 23 de Dic. de 2011
Interesting. Looks like the math might be tricky since some cases weren't solved (or "proved optimal") until the late 1960's. Have you tried to get the code from the Wolfram site? Would you be interested in a Monte Carlo solution to get a random configuration?
Image Analyst
el 23 de Dic. de 2011
Editada: Image Analyst
el 17 de En. de 2020
Carlas: Someone asked this a year or two ago in the newsgroup. Here is the demo I made for him. It should be a simple matter to check for overlap before plopping down the next circle.
% M-file to place multiple small circles inside a big circle.
% Clean up
close all;
clc;
% Initialize some parameters.
numberOfSmallCircles = 25; % Number of small circles
smallCircleOutsideValue = 0.2;
smallCircleInsideValue = 0.8;
smallCircleRadius = 25; % small circle radius
bigImageWidth = 500;
bigImageHeight = 500; % square area 0f 500*500
bigCircleRadius = 250; % big circle radius
% Initialize an image to hold one single big circle.
bigCircleImage = zeros(bigImageHeight, bigImageWidth);
[x, y] = meshgrid(1:bigImageWidth, 1:bigImageHeight);
bigCircleImage((x - bigImageWidth/2).^2 + (y - bigImageHeight/2).^2 <= bigCircleRadius.^2) = 1;
% Display it in the upper left plot.
subplot(3,2,1);
imshow(bigCircleImage, []);
title('Big Circle Mask');
set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.
% Initialize an image to hold one single small circle.
smallCircleImage = zeros(2*smallCircleRadius, 2*smallCircleRadius);
[x, y] = meshgrid(1:smallCircleRadius*2, 1:smallCircleRadius*2);
singleCircleImage = zeros(2*smallCircleRadius, 2*smallCircleRadius);
singleCircleImage((x - smallCircleRadius).^2 + (y - smallCircleRadius).^2 <= smallCircleRadius.^2) = smallCircleInsideValue;
% Display it in the upper right plot.
subplot(3,2,2);
imshow(singleCircleImage, []);
title('Single Small Circle (scaled to fit)');
singleWidth = size(singleCircleImage, 2);
singleHeight = size(singleCircleImage, 1);
% Get random coordinates in the big image where
% we will place the upper left corner of the small circle.
widthThatWillFit = bigImageWidth - 2 * smallCircleRadius;
heightThatWillFit = bigImageHeight - 2 * smallCircleRadius;
smallUpperLeftX = widthThatWillFit * rand(numberOfSmallCircles, 1);
smallUpperLeftY = heightThatWillFit * rand(numberOfSmallCircles, 1);
% Initialize an output image to hold many small overlapping circles.
manySmallCircles = zeros(bigImageHeight, bigImageWidth);
% Place the small circles one by one.
for k = 1 : numberOfSmallCircles
% Find the square in the big image where we're going to add a small circle.
x1 = int16(smallUpperLeftX(k));
y1 = int16(smallUpperLeftY(k));
x2 = int16(x1 + singleWidth - 1);
y2 = int16(y1 + singleHeight - 1);
% Add in one small circle to the existing big image.
manySmallCircles(y1:y2, x1:x2) = manySmallCircles(y1:y2, x1:x2) + singleCircleImage;
end
% Make outside the circles the outside color.
manySmallCircles(manySmallCircles == 0) = smallCircleOutsideValue;
% Display it in the lower left plot.
subplot(3,2,3);
imshow(manySmallCircles);
title('Many Small Overlapping Circles');
% Multiply the big circle mask by the many small circles image to clip
% those small circles that lie outside the big circle.
maskedByBigCircle = bigCircleImage .* manySmallCircles;
% Display it in the lower right plot.
subplot(3,2,4);
imshow(maskedByBigCircle);
title('Many Small Circles Masked by Big Circle');
% Take the histogram and display it in the bottom row.
subplot(3,2,5);
hist(maskedByBigCircle(:));
grid on;
title('Histogram of image', 'FontSize', fontSize);
![0000 Screenshot.png](https://www.mathworks.com/matlabcentral/answers/uploaded_files/262145/0000%20Screenshot.png)
MOHAMMED ALMUBAYEDH
el 18 de En. de 2017
is there a way to input the small circle diameter then input the large circle diameter and then get the output of how many circles I can fit
1 comentario
Image Analyst
el 18 de En. de 2017
As a partial answer, you can use patch() or fill() to place colored rectangles (with some opacity) over the image.
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