Dear Vivek Kumar Verma, 

Look the link, please.

http://ijssst.info/Vol-15/No-2/data/3251a285.pdf

Regards, Shafagat

I think it is very similar to the problem of counting bacteria colonies. For the bacteria colonies counting, there are a lot of software for free, so you can use some of them, e.g., openCFU http://opencfu.sourceforge.net/ 

I'm sure it will works for the problem of cell counting too.

In addition, something that might also work is cross correlation,

if you have a sample image of one cell and the cells have

roughly the same 2D size.

http://docs.opencv.org/2.4/doc/tutorials/imgproc/histograms/template_matching/template_matching.html

Regards,

Joachim

ImageJ has an automatic particle counting function

Now New Technique in this matter. like 5D system. developed by Dr... he is belongs from India in Amaravati. (Nagpur) Pl contact him.  I don't know perfect but listen he live in USA.