Detection of parts of circles (shape detection)

Hello,

please see attached the following images.

I want to detect the lense in my picture (the 2 bright rings) and then want to inpaint it. Throughout the frames, sometimes the lense is fully in the picture and sometimes not, which makes circle detection kinda useless, is there any way to make use of roundness or other detection to find the (partly) circular object in the picture?

I tried tressholding with an binary image but the brightness of the picture is to uniform to get a clear result.

Edit: I could produce the following picture. Is there any way to detect the blue half circles as a sole object (the lense)? I approximatly know the radius of both lenses if that can help.

Thanks for any advice

Best Regards

Answer 1

[Stephan]

I dont think that this is correct: "...sometimes the lense is fully in the picture and sometimes not, which makes circle detection kinda useless..." At least it is worth a try because Matlab can do this job. See example here:

https://de.mathworks.com/help/images/measuring-the-radius-of-a-roll-of-tape.html

[Fabian Ziegler]

I am not able to detect any circles with the imfindcircle function sadly. No centre/radii will be found no matter what picture i use