How do I fit an ellipse to a partial ellipse image?

I have a binary image which contains a part of an ellipse. Now, I would like to fit an ellipse to this data:

 I have tried regionprops, but this doesn't work because it doesn't contain a 
whole ellipse:

How can I fit an ellipse following the borders of the partial ellipse image?

It would be even better to separate the binary image in a left and right part and fitting two separate ellipses for the left and right part.

Any help is appreciated.

Answer 1

[Image Analyst]

See the FAQ: http://matlab.wikia.com/wiki/FAQ#How_can_I_fit_an_ellipse_or_other_shape_to_a_set_of_XY_data.3F

Be sure to remove any points where y = 1 or y = the number of rows in the image because you do not want to include the flat top and bottom in the fit.

Answer 2

[Michal]

I've use this one from Matlab File Exchange in the past and it worked nicely

kudos to Ohad Gal for this one :)

https://www.mathworks.com/matlabcentral/fileexchange/3215-fit_ellipse?s_tid=srchtitle