GUI How to make multiple slider

Hi, I am trying to write edge detection that threshold based on length and intensity. I create a ui for it but everytime i update length then intensity got resetted and everytime i update intensity length got resetted. how do i make sure the data is kept. means if intensity 10 and length 10 and i push slider so length 100 then intensity stays at 10 not go back to 0. code below help thanks

function myui

    Im = imread('42049.jpg');

    threshold = 0;
    length = 10;

    % Create a figure and axes
    f = figure('Visible','off');
    ax = axes('Units','pixels');

    BW = edge(Im, 'sobel', threshold);
    imshow(BW);

   % Slider for threshold
    sld = uicontrol('Style', 'slider',...
        'Min',0,'Max',1,'Value',0,...
        'Position', [400 20 120 20],...
        'Callback', @thresh_slider); 

    % Slider for length
    sld = uicontrol('Style', 'slider',...
        'Min',0,'Max',500,'Value',0,...
        'Position', [200 20 120 20],...
        'Callback', @length_slider); 
          
    % Add text for slider
    txt = uicontrol('Style','text',...
        'Position',[400 45 120 20],...
        'String','Threshold');

    txt = uicontrol('Style','text',...
        'Position',[200 45 120 20],...
        'String','Length');

    % Make figure visble after adding all components
    f.Visible = 'on';

    function thresh_slider(source,callbackdata)
        threshold = source.Value;

        BW = edge(Im, 'sobel', threshold);

        ConnectedComponents = bwlabel(BW);

        a = unique(ConnectedComponents);
        out = [a,histc(ConnectedComponents(:),a)];

        FinalImage = zeros(size(BW,1), size(BW,2));
        for i = 1:size(ConnectedComponents,1)
            for j = 1:size(ConnectedComponents,2)

                componentID = ConnectedComponents(i,j);
                componentLength = out(componentID+1,2);

                if(componentID == 0) 
                    FinalImage(i,j) = 0;
                elseif(componentLength > source.Value && componentID ~= 0)
                    FinalImage(i,j) = 1;
                end
            end
        end

        imshow(FinalImage);

    end

    function length_slider(source,callbackdata)
        length = source.Value;

        BW = edge(Im, 'sobel', threshold);

        ConnectedComponents = bwlabel(BW);

        a = unique(ConnectedComponents);
        out = [a,histc(ConnectedComponents(:),a)];

        FinalImage = zeros(size(BW,1), size(BW,2));
        for i = 1:size(ConnectedComponents,1)
            for j = 1:size(ConnectedComponents,2)

                componentID = ConnectedComponents(i,j);
                componentLength = out(componentID+1,2);

                if(componentID == 0) 
                    FinalImage(i,j) = 0;
                elseif(componentLength > length && componentID ~= 0)
                    FinalImage(i,j) = 1;
                end
            end
        end

        imshow(FinalImage);

    end
end