function y = Pool(x)

% This function takes the feature map and returns the image
%after the 2x2 mean pooling process.

[xrow, xcol, numFilters] = size(x);
y = zeros(xrow/2, xcol/2, numFilters);

for k = 1:numFilters
    filter = ones(2)/(2*2); % for mean
    image = conv2(x(:,:,k), filter, 'valid');
    y(:,:,k) = image(1:2:end, 1:2:end);
end

end