How do I segment the black spherical looking regions and remove unnecessary noise?

This is the image of a soil sample, I processed it to convert it into complete black and white binarized image. After that, I used the iamadjust command to negative the binary image. I want to remove the small unnecessary noise in the image and then segment individual spherical shapes separated by white boundaries. And at the end, I would like to find the black to total area ratio. Please help me with that. I have attached the all three images and I made it negative because I feel the segmentation would be easier in for that image only, in case segmentation is easier with the binary image then

proceed with the same.

[shivam sahil]

This is the better

preview of the negative image.