Hi everyone, I’m trying to measure diameter of microbubble images but I got a difficulty in image threshold. the gray color is so close to the bubble color even the reflection inside bubbles.
I try to measure it one by one and it takes lots of time. Any solution or suggestion please share 
PS. I used a micro lens camera with backlight technique to take this microbubbles pictures if anyone have suggestions on camera works also please guide me.
Thank you
James
Do you have any control over the sample density? I imagine that it would be a lot easier if there were fewer microbubbles.
Thanks for the reply,
I need to fixed the air flowrate in this condition, even the low flowrate (100ml/min) also have this problem.
Maybe you could provide a diagram showing how you are currently doing the imaging? Also, I’m not sure what “micro lens camera” is. Is this a camera with lens on the chip to improve quantum efficiency? Or are you trying to do some kind of light field imaging with a micro lens array?
Assuming that you are imaging with a normal upright or inverted microscope geometry I’d suggest dark field imaging as a possible alternative. Then hopefully you would only see the light scattered by the bubbles, and they would appear as bright spots on a dark background. You might also be able to figure out a relation between the brightness and the size after analyzing a few examples by hand, and then you could use this relation to quickly estimate the size of all of the bubbles in the FOV.
Can you trap a fluorescent carrier inside the microbubbles when they are produced? Presumably this would provide massive signal to noise as long as your camera is for imaging fluorescence.
