How to extract contour line from my image

'I delete picture after getting answer. Thanks for answer'

Hello! I really want big help of your intelligence.

I want to extract contour from inserted image. But I cannot delete unnecessary figures like mark, word etc. I try to do some example in matlab answers of other question, but it is not applied to my image. How can I extract contourline? please help me.

Answer 1

[Image Analyst]

Why? What's the "use case"?

All I can suggest is bwselect() but your contour lines are very very broken so you may just get part of one.