cross curves tracking

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C++

C#

C#4.0

hello, there are several cross curves in a Optical digital image， I want to track one curve of them given the input point. I have try many ideas, but effect is still not good. please give me some suggestion or some software
codes.
for example, in a historical seismogram paper, there are many waves which cross each other, now i want to trace one wave along one start point.
Thank you very much!