The shape formed keeps changing with a change in velocity, and angle of the flow. I want to measure the distance centre orange line, and the yellow lines on both sides. The starting point will be fixed to the place where the two flows collide.

The process I’m following is:

1. To detect the edges and manually select the starting point.

2. Find the endpoint and measure the distance in pixels and later convert it to desired units.

I’m not sure how to do step 2. And also if this is the best approach to do this to find droplet size?

What would be the best approach to achieve this?

Length to be measured

Sample image 1

Sample image 2