AdaBoost/readMNIST.m at master · shashanktyagi/AdaBoost · GitHub

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function [imgs, labels] = readMNIST(imgFile, labelFile, readDigits, offset)

    % Read digits
    fid = fopen(imgFile, 'r', 'b');
    header = fread(fid, 1, 'int32');
    if header ~= 2051
        error('Invalid image file header');
    end
    count = fread(fid, 1, 'int32');
    if count < readDigits+offset
        error('Trying to read too many digits');
    end

    h = fread(fid, 1, 'int32');
    w = fread(fid, 1, 'int32');

    if offset > 0
        fseek(fid, w*h*offset, 'cof');
    end

%     imgs = zeros([h w readDigits]);
    imgs=zeros(readDigits,h*w);

    for i=1:readDigits
        for y=1:h
%             imgs(y,:,i) = fread(fid, w, 'uint8');
            imgs(i,(28*(y-1)+1):28*y)=fread(fid,w,'uint8');
        end
    end

    fclose(fid);

    % Read digit labels
    fid = fopen(labelFile, 'r', 'b');
    header = fread(fid, 1, 'int32');
    if header ~= 2049
        error('Invalid label file header');
    end
    count = fread(fid, 1, 'int32');
    if count < readDigits+offset
        error('Trying to read too many digits');
    end
    if offset > 0
        fseek(fid, offset, 'cof');
    end

    labels = fread(fid, readDigits, 'uint8');
    fclose(fid);

    % Calc avg digit and count
%     imgs = trimDigits(imgs, 4);
    imgs = normalizePixValue(imgs);
    %[avg num stddev] = getDigitStats(imgs, labels);

end

function digits = normalizePixValue(digits)
    digits = double(digits);
    for i=1:size(digits, 3)
        digits(:,:,i) = digits(:,:,i)./255.0;
    end
end