I agree with Sir Chandra Bhanu, My colleague did the same steps but that depends on the quality of your picture.

Cordially

http://airccse.org/journal/ijsc/papers/3312ijsc01.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2493467/

http://www.nature.com/articles/srep24864

So long as you have a good image which shows porosity in the sample you can use ImageJ software. You should have share a sample micrograph to make people understand if it is possible to do the analysis or not. However, the basic steps are as follows -

1. Set scale of the image in ImageJ

2. Make your image into a 8bit image (within ImageJ)

3. Adjust contrast and brightness.

4. Threshold your image.

5. Do "analyse particle" (ImageJ doesn't know if it is a pore or particle!!)

I agree with Sir Chandra Bhanu, My colleague did the same steps but that depends on the quality of your picture.

Cordially

Thanks Sir Chandra Bhanu Basak..but what value in the table shows porosity.