function [len_M, num_true] = add_dataset(image_file, csv_file, dataset_folder)

% parameters

d = 10;

d2 = d*d;

N = 101; % must be odd

R = (N-1)/2;

S = R + d;

% create list of coordinates within a circle of radius d

k = 1;

for i=(1-d):(d-1)

    for j=(1-d):(d-1)

       if i*i + j*j < d2

           region(k,:) = [i j];

           k = k + 1;

       end

    end

end 

% load image and csv files

A = imread(image_file);

M = csvread(csv_file);

[A_height, A_width, ~] = size(A);

% extend the image by mirroring (just for the positive samples)

D = padarray(A,[S S],'symmetric');

% find the centroids

len_M = size(M,1);

P = zeros(len_M,2);

for i=1:len_M;

    tmp = M(i,:);

    tmp = tmp(tmp~=0);

    len_tmp = size(tmp,2);

    sum_X = 0;

    sum_Y = 0;

    for j=1:len_tmp/2

        sum_X = sum_X + tmp(2*j-1);

        sum_Y = sum_Y + tmp(2*j);

    end

    mean_X = 2*sum_X/len_tmp;

    mean_Y = 2*sum_Y/len_tmp;

    P(i,:) = [mean_Y mean_X];

end

M = round(P);

% create positive dataset

% extract many images within a region around each mitosis

len_region = size(region,1);

B = cell(1,len_M*len_region);

for i=1:len_M

    for j=1:len_region

        y1 = M(i,1) + region(j,1) - R + S;

        y2 = M(i,1) + region(j,1) + R + S;

        x1 = M(i,2) + region(j,2) - R + S;

        x2 = M(i,2) + region(j,2) + R + S;

        %{

        if y1 >= 1 && y2 <= A_height && x1 >= 1 && x2 <= A_width

            B{j+(i-1)*len_region} = A(y1:y2, x1:x2, :);

        end

        %}

        B{j+(i-1)*len_region} = D(y1:y2, x1:x2, :);

    end

end

%B = B(~cellfun('isempty', B));

% create negative dataset

H = A_height - N + 1;

W = A_width - N + 1;

num_true = length(B);

C = cell(1,num_true);

for i=1:num_true

    flag = true;

    while flag

        X = randi(W);

        Y = randi(H);

        flag = isPos(X,Y,M,d);

    end

    y1 = Y;

    y2 = Y + 2*R;

    x1 = X;

    x2 = X + 2*R;

    C{i} = A(y1:y2, x1:x2, :);

end

% write set of images to file

n = length(dir([dataset_folder 'true/*.png']));

for i=1:num_true

    file1 = [dataset_folder 'true/' num2str(i+n,'%02u') '.png'];

    file2 = [dataset_folder 'false/' num2str(i+n,'%02u') '.png'];

    imwrite(B{i}, file1, 'png');

    imwrite(C{i}, file2, 'png');

end