dc offset for negative intensity (optional)

for ii=1:length(intensity)

    dod(ii) = DataClass();

    d = intensity(ii).GetDataTimeSeries();

    % Optional (user prompt): Adding dc offset if intensity (d) has negative values

    if ~isempty(d<=0)

        quest = {'Intensity signal has negative values. If you would like to add a dc offset, please click YES. If you would like to proceed with negative values, hit CANCEL.'};

        dlgtitle = 'Warning';

        btn1 = 'YES';

        btn2 = 'CANCEL';

        detbtn = btn1;

        answer = questdlg(quest,dlgtitle,btn1,btn2,detbtn)

        switch answer

            case 'YES'

                for j = 1:size(d,2)

                    foo = d(:,j);

                    if ~isempty(foo<0)

                        d(:,j) = foo + abs(min(foo));

                        foo = d(:,j);

                    end

                    if ~isempty(foo == 0)

                        d(:,j) = foo + min(foo(foo > 0));

                    end

                end

        end

    end

    dm = mean(abs(d),1);

    nTpts = size(d,1);

    dod(ii).SetTime(intensity(ii).GetTime());