Weld butt detection.

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Hello guys. My first question here. I am trying to detect the center of butt weld, example in first image below.

1.Weld

So far i have tried with template matching that openCv library offers. Basically i created a bunch of 2 pixel width samples from gauss filtered images used them with matchTemplate. So far i have produced the following results.

1.Result 1

I hope you can see the white line. I used the moving average method to smoothen the line and remove high frequencies. The problem is that, this is not good enough for me. Can anyone tell me if there is any another way to do this. (i tried to get the result by playing with intensities and setting the conditions in code but that is even worse, because the weld butt is very inconsistent with brightness).

Thanks for any answers.