How do I find the number of circles in an image? I've given the code I used and output image below

clc; close all; clear all; a=imread('C:\Users\Hema\Desktop\nonemptylot.jpg'); b=imread('C:\Users\Hema\Desktop\emptylot.jpg');

[x,y]= size(a); [c d]=size(b);

e=rgb2hsv(a); f=rgb2hsv(b); subplot(1,2,1) imshow(e); title('HSV of Nonempty'); centers = imfindcircles(e,[20 20]); [centers,radii] = imfindcircles(e,[5 15]); [centers,radii,metric] = imfindcircles(e,[5 15]); BW=size(viscircles(centers, radii,'EdgeColor','b')); STATS = regionprops(BW,'EquivDiameter');

subplot(1,2,2) imshow(f); title('HSV of empty'); centers = imfindcircles(f,[20 20]); [centers,radii] = imfindcircles(f,[5 15]); [centers,radii,metric] = imfindcircles(f,[5 15]); BW=size(viscircles(centers, radii,'EdgeColor','b')); STATS = regionprops(BW,'EquivDiameter');

disp(STATS);

Answer 1

[Jayanti]

Hi Soundarya,

“imfindcircles” function returns the centers and radii of the detected circles. The number of circles is simply the length of the centers array. “centers” is a matrix where each row represents a circle.

[centers1, radii1, metric1] = imfindcircles(e, [5 15]);
numCirclesNonEmpty = size(centers1, 1);

[centers2, radii2, metric2] = imfindcircles(f, [5 15]);
numCirclesEmpty = size(centers2, 1);

The below code

size(centers, 1);

will return the size of the first dimension of the “centers” matrix. Which corresponds to the number of detected circles.

[Image Analyst]

And you can use viscircles to show them in the overlay above where they were found.