www.gusucode.com > 有监督的 CNN 网络完成对MNIST 数字的识别 > 有监督的 CNN 网络完成对MNIST 数字的识别/CNN—卷积神经网络数字识别/subsample.m

     function out = subsample(in, ratio) 
        
        switch ratio
            case 4
                out = 0;
                for k=1:4
                    for l=1:4
                        out = out+in(1+(k-1):4:size(in,1),1+(l-1):4:size(in,2));
                    end
                end

                out = out/16;
            case 2
                out = (in(1:2:size(in,1),1:2:size(in,2)) + in(1:2:size(in,1),2:2:size(in,2))...
                    +in(2:2:size(in,1),1:2:size(in,2)) + in(2:2:size(in,1),2:2:size(in,2)))./4;
                
            case 1
                out = in; 
            otherwise disp('Unsupported ratio');
        end
       
%    out = out.*ws + bs;        
    end