Measure diameter of microbubble images

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 :slight_smile:
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 :slight_smile:

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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.