finding the volume of the pores in the 3D image

HI this is RK .I am working on a project for geo science.my job is to find the porosity of a Basalt rock.I have been given a task of stacking 2d images to form 3D image and to find the porosity of that 3D rock(Basalt rock)..the rock looks exactly like a swisscheese....

http://www.jlfstone.com/images/lavastone/LavaStone.jpg

http://www.istockphoto.com/file_thumbview_approve/11517171/2/istockphoto_11517171-swiss-cheese-slice.jpg

http://abcnews.go.com/images/Health/nm_swiss_cheese_081125_main.jpg

I am new to matlab.can anybody help me how to start with .or any functions of matlab which will be useful in my project...

Answer 1

[Sean de Wolski]

Upper threshold the gray scale image. To find a threshold I would recommend starting with Otsu's method.

 I = your_image;
 lvl = graythresh(I);
 Ipores = ~im2bw(I,lvl); %invert to pores are true

Then porosity and all pore statistics can be calculated by doing a connected components analysis and regionprops

 CC = bwconncomp(Ipores);%default 26 connectivity 
 RP = regionprops(CC); %doc regionprops to find out various things.

Good Luck!

-Sean

[ramakrishna bathini]

one quick question....can we see graphically only the pores erasing the solid part??? one more thing how to see the outputs of CC and RP after the regionprops..read a bunch of related docs but couldn't get..

[ramakrishna bathini]

ma bad.. not graphically but can we see an image of only the pores erasing the solid part ..is it possible?

[Sean de Wolski]

That's what Ipores, is. Or do you want it in original color? If so:

Ipores_orig = cast(Ipores,class(I)).*I;

[ramakrishna bathini]

the above function highlights the pores. gives much realistic feel..but can we erase the solid part??

[Sean de Wolski]

What do you mean by "erase"? My above comment removes all non-pores.

[ramakrishna bathini]

actually its not displaying only pores...can i mail you my outputs???