Hi Boaz,
I understand that the analysis software you are using is expecting a 4-character array where the fourth character is not just a space, but a specific type of whitespace or non-printing character that is not being replicated when you simply add a space using ' '.
In MATLAB, you can try creating a 4-character array where the fourth character is a different type of whitespace, such as a non-breaking space (char(160)) or another non-printing character that might be interpreted as "empty" by the analysis software.
Here's how you can try setting the "voxel_order" field with different types of whitespace characters:
% Your failing header struct
header.failing.voxel_order = 'LAS';
% Option 1: Try adding a non-breaking space (ASCII 160)
header.failing.voxel_order(4) = char(160);
% Option 2: Try adding a null character (ASCII 0)
header.failing.voxel_order(4) = char(0);
% Option 3: Try adding a horizontal tab (ASCII 9)
header.failing.voxel_order(4) = char(9);
% Check if the voxel_order is now a 1x4 char
disp(header.failing.voxel_order);
The error message you're seeing from the Python-based analysis software suggests that it's expecting a set of axis codes that includes None for the fourth character, which might be interpreted as a null character or some other non-printing character in Python.
Remember to save the header after modification if needed, so that you can use it with the analysis software.
