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: waveidtb_getEstimates3D.m
    path of file: ./repos/bspm/thirdparty/MIALAB/WaveIDioT_1a
    
    the code of the file until where you have to start completion: function [y_est] = waveidtb_getEstimates3D(D , Dprev , sig , K)

% Initialize the classification
% x = zeros( size(D) );
y = Dprev;

% Calculate the mask
x = (abs(D).*abs(y) ) >= ( (K^2)*sig);

% Estimate the wavelet coefficients after the mask has been obtained
% Get Magnitudes
m = abs(D);

    
function [y_est] = waveidtb_getEstimates3D(D , Dprev , sig , K)

% Initialize the classification
% x = zeros( size(D) );
y = Dprev;

% Calculate the mask
x = (abs(D).*abs(y) ) >= ( (K^2)*sig);

% Estimate the wavelet coefficients after the mask has been obtained
% Get Magnitudes
m = abs(D);

% Compute the locally averaged coefficient magnitude
[M,N,O] = size(D);

% Find the ratio of 1's to 0's in x
if ( sum(x(:)) < M*N*O )
    r = sum(x(:))/(size(x,1) * size(x,2) * size(x,3) - sum(x(:)));
else
    r = 100;
end