how to find an eclipse in an image

i'm trying to find the eclipse in an image

1. i first use filter over the image

function [im_new]=getfilter(im)

imm1=imgaussfilt(im,10);

imm2=medfilt2(imm1,[5,5]);

imm3=imresize(imm2,0.25);

imm4=imresize(imm3,4);

im_new= imm4;

end

2. then i try to find the eclipse but for some reason the algorithm is failing.

function[s,Thr]=findeclipse(im,itrun)

counts=hist(im(:),0:255);

Thr=otsuthresh(counts);

imm5=im2bw(im,Thr);

diskrange=1;

while 1 %iterating filtering util get the one circle

SE = strel('disk',diskrange,0);

BW2 = imerode(imm5,SE);

BW3 = imdilate(BW2,SE);

s = regionprops(BW3,{...

'Centroid',...

'MajorAxisLength',...

'MinorAxisLength',...

'Orientation'});

if (length(s)>=1)&&(length(s)<2)

break

elseif length(s)==0

error('Could not find the pattern')

break

end

diskrange= diskrange+1;

end

end

need some assist fixing the code for the attach image

thanks,

Answer 1

[Shreeya]

"regionprops" function in MATLAB can be used for detecting eclipses. You can check the eccentricity of the connected component and then classify it as an eclipse/circle/line etc depending on your use case. Refer to the link below:

https://www.mathworks.com/help/images/ref/regionprops.html