Does it work well on the real corneal Endothelium image?

[hensonwells]

Hi,there.
I got some trouble in preprocessing the real corneal Endothelium image.
The preprocessing result of the img was much far from my expected.
I wish to count the numbers of the cells，but the preprocess method doesn't work well.
My preprocessing result followed here,do you have any idea to make it work?
Looking forward for ur reply.
appreciate of it.