Find symmetry point/center point in an irregular image

I am trying to find symmetry lines or points in my image

My main aim is to find the center of this contour. But I can't use thresholding, so can't use OpenCV contours. So my next guess it to find symmetric point in my image and hopefully that will correspond to the center of this contour. Any other idea to find center of this contour is also appreciated, something which doesn't involve thresholding as I can't give parameters to user. I tried finding centroid using cv moments but that didn't give me good results. I tried using hough circle detection, but it couldn't detect this as circle.

I am using python and OpenCV.

Solution 1:

The question is rather vague, lacking adequate sample images and there is little feedback to comments, so it is a stab in the dark as whether you are having difficulty separating the objects, or finding their lines of symmetry, but I wanted to point out that ImageMagick does a pretty good job of separating the objects using the algorithm described here.

Here it is from command line with dithering suppressed:

magick IuOWe.jpg +dither -colors 3 result.jpg

And here with initial blurring:

magick IuOWe.jpg -blur 0x5 +dither -colors 3 result.jpg

Of course you can use similar techniques with OpenCV, or scikit-image as you have tagged Python - it is just quicker to demonstrate my avenue of thought using ImageMagick.