How does that convert the data to a linear scale unless it's the inverse of a non-linear transformation that made it non-linear in the first place?
Assuming matrix is actually a table (misleading variable name), nothing appears to be wrong with the line of code you're using.
Based on the error message, you may have forgotten to index the table and may have mistakenly tried to execute
Col2linear = 10.^(( matrix -30)/10); % wrong
or
Col2linear = 10.^(( matrix(:,2) -30)/10); % wrong
instead of what you have written,
Col2linear = 10.^(( matrix.column2 -30)/10); % appears to be correct
Otherwise we'll need more information about what matrix and matrix.column2 is. Is column2 a sub-table?
