How can I find the meaningfule peaks?

Hi,

I am analyzing a flame's UV picture(attatched file). As the picture shows, the flame image has two branches connected at the bottom. I want to remove all other pixels except locan maxima long the branches. draw a curve which combined local maxima along the two branches. I have used findpeaks and found the largest and the second largest peaks with the condition that those two peaks should have been separated with the distance larger than the threshold. But the problem is thoes brances were connected at the bottom. Please let me know how I can find the meaningful peaks.