How to store different values of regionprops inside a structure from a 3D matrix

Hello,

I have a 3D matrix containing 16 binary images. Each of these 16 images are containing multiple regions (of different size and shape) inside them. I want to be able to calculate regionprops of each of those 16 images and their regions inside them. I was able to calculate Centroids and BoundingBox for each region separately of each image and store them in a 1x16 structure containing these two fields ( Centroids and BoundingBox ).

But, I am not being able to calculate PixelValues for each of those regions inside each of those 16 images and store them also inside my 1x16 struct and adding the third field (that would be PixelValues ).

Here is the piece of my code where I'm having trouble:

 numImages - is a number of images inside my 3D matrix (16 of them)

 for i=1:numImages
 j = regionprops(logical(bw(:,:,i)), M2(:,:,i), {'Centroid','PixelValues','BoundingBox'});
 jj(i).Centroids = [j.Centroid];
 jj(i).Centroids=reshape(jj(i).Centroids, 2, []);
 jj(i).Centroids=transpose(jj(i).Centroids); %%Here I reshaped these values in order to put them in Nx2 matrix

 jj(i).PixelValues = [j.PixelValues]; %%Here lies the problem andI do not know how solve it

 jj(i).BoundingBox = [j.BoundingBox];
 jj(i).BoundingBox=reshape(jj(i).BoundingBox, 4, []);
 jj(i).BoundingBox=transpose(jj(i).BoundingBox);%%Here is the same thing, except it was Nx4 matrix
 end

The problem that I have with my code (regarding PixelValues ) is that each region contains different number of pixels in them and that is the problem that is causing me to get this error:

 Error using horzcat
 Dimensions of matrices being concatenated are not consistent.

It was easier to separate those values for Centroids and BoundingBox since each Centroid contains only two values(x and y coord.) and BoundingBox containing 4 values (which define the box).

But with the PixelValues each region contains different number of those values. Here is the example for only one image containing 21 regions:

region1: 15840x1,

region2: 28x1,

region3: 131;131;131;131;,

region4: 37x1,

and so on...

To elaborate a little bit more I have attached the image of my structure.

Thanks in advance!

Answer 1

[Image Analyst]

Put them into a cell array

[Mario]

Do you care to elaborate on that please?

I tried with:

 jj(i).PixelValues = j(i).PixelValues;

and I get the PixelValues of only the last image and it's regions.

How can I do that for all images and their regions?

and I also get the error:

 Index exceeds matrix dimensions.

Thanks!

[Mario]

I managed to get it to work

I used

 jj(i).PixelValues = {j().PixelValues}.';

and was able to get PixelValues of all regions as a separate cell inside my 1x16 structure.

Thanks for the hint.

[Image Analyst]

Maybe this (untested)

for k = 1 : length(j) % for every blob...
    % Put this blob's array into the kth cell.
    ca{k} = j(k).PixelValues; 
end
% Make the cell array a field of the i'th
% element of jj structure array.
jj(i).PixelValues = ca;