You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spm_eeg_megheadloc.m
    path of file: ./repos/bspm/thirdparty/spm12/toolbox/MEEGtools
    
    the code of the file until where you have to start completion: function D = spm_eeg_megheadloc(S)
% Use head localization of CTF to select/reject trials based on head
% position and (optionally) correct the sensor coordinates to correspond to
% the selected trials. The
    
function [obj, captured] = trials_captured(center, dat, threshold)

nsmp    = size(dat,2);
dist = max(sqrt([1 1 1 0 0 0 0 0 0; 0 0 0 1 1 1 0 0 0; 0 0 0 0 0 0 1 1 1]*(dat - repmat(center(:), 1, nsmp)).^2));
obj = -sum(dist<threshold);

if nargout>1
    captured=dist<threshold;
end