How to evaluate the area of a blob which has maximum centroid value of Y coordinate (lowest blob in a image) ?

Hello I am trying to calculate the bubble detachment frequency from a nozzle injecting air in a water pool from bottom. For that I want to avaluate the area only for the lowest blob, so that with change in area I may calculate the detachment frequency. I have binarized my image, filled the holes and calculated the area for all the blobs as well. But I am unable to find a way to record only lowest blob's area for every frame of an video.

Answer 1

[darova]

Calculate area for each blob then select only one you need