As per my understanding, based on the given code the voxels are classified into two groups, the one with the given set of indices are classofoed as 0 and all the other as 1s.
To optimize the code provided, you may first create an array of voxels which you want to classify as 0. Assuming the voxel array name as regions_zero and the given matrice is tissue, ismember(A,B) function can be used which will return an array containing the logical indexing if the voxel is found in both the tissue matrix and the regions_zero matrix. Using the logical indexing we can group the two regions using the below code:
% Assuming you have a 3D volume named 'tissue' and you want to set specific regions to zero and the rest to one
% Define the regions you want to set to zero
regions_zero = [24, 31, 32, 33, 37, 38, 39, 40, 41, 42, 43, 44, 48, 49, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, ...
66, 67, 70, 72, 73, 74, 76, 77, 81, 82, 83, 84, 85, 86, 87, 89, 90, 91, 92, 93, 94, 96, 97, 101, 102, 103, 104, ...
105, 106, 107, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 129, 130, 133, ...
134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, ...
157, 158, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, ...
182, 183, 184, 185, 186, 187, 188, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, ...
207, 208];
% Set the specified regions to zero and the rest to one
tissue(~ismember(tissue, regions_zero)) = 1;
tissue(tissue ~= 1) = 0;
You can refer to the following documentation to know more about the ismember() function:
Thank You!
Maneet Bagga
