Filling in cell area and counting cells

What code could be used to fill in these arbitrarily shaped cells that also gets ride of the smaller cells that look like noise and then count the number of cells?

Answer 1

[Image Analyst]

You can use imfill() and bwareafilt() or bwareaopen():

mask = imfill(mask, 'holes'); % Fill holes.
mask = bwareafilt(mask, [30, inf]); % Extract only blobs 30 pixels or larger.
[labeledImage, numberOfCells] = bwlabel(mask); % Count blobs.