Minimum object size for recognition?

Question

Neural networks

Hello!
Is it possible to recognize micron-sized objects in a photo?
For example, foreign particles in sand.

Answer 1

You do not recognize the physical size of the object, but the size of the object in the picture.
Accordingly, the key point is the resolution of your image.
The higher, the more accurate the recognition result will be.

Answer 2

A leading question: how many pixels in the photo will the object occupy? How homogeneous is the sand? Further themselves.