Internal porosity of 3D volume object - part (B)

Hi everyone again,

Original question: I want to find out the internal pores of a volume object. This 3D object is resulted from binary images of X-ray tomography and then its voxel information is processed to obtain this 3D volume object. Any suggestion or guidance would be highly appreciated. Thanks

As answered by 'Image Analyst', I got the following method to compute the internal porosity of these different coloured particles.

'Threshold to find material and sum the image. That's the material volume. Then invert that threshold so that now you have non-material/air. Now call imclearborder() to get rid of the surrounding air region. Then sum the volume, which will give you the volume of the internal void spaces. Then divide those two to get the volume fraction = (volume of material) / (volume of void spaces)'

someThreshold = 3000; % Whatever...
% Threshold.
material = image3D > someThreshold;
% Get volume
materialVolume = sum(material(:))
% Get air space
air = ~material;
% Remove surrounding air
air = imclearborder(air);
% Sum air space left, i.e. void spaces inside the material.
voidSpaceVolume = sum(air(:))
% Compute total volume
totalVolume = materialVolume + voidSpaceVolume 
% Calculate ratios.
materialRatio = materialVolume / totalVolume 
voidSpaceRatio = voidSpaceVolume / totalVolume

My query is as following, if someone please could help me in detail.

At first I thought it is simple to apply but now I am facing difficulties.

Firstly please tell me what is the purpose of thresholding? in my case material is fixed (Maltodextrin) if necessary then please guide how should I perform thresholding.

Secondly my input is a complete 3D volume object. Please check it in this 'fig' format of MATLAB but it is resulting from a set of binary images obtained from X-ray tomography. So should I use my binary images as an input over here?

P.S.: I have made this new thread becasue the older one was not responsive anymore.

Please guide me I am stuck over here from last week not getting any idea to move forward.

Answer 1

[Sean de Wolski]

Consider using the volume method of alphaShape

[yu sh]

Can you please refer me any tutorials regarding this? Or kindly elaborate me in detail that how can I exactly compute the internal porosity of these 3D particles using volume method of alphaShape?