运行环境：Matlab2014b

部分代码：

%% 视频流循环处理
% 创建一个循环过程来对给定视频进行车道线检测
% 该循环使用之前初始化的系统对象
warningTextColors = {[1 0 0], [1 0 0], [0 0 0], [0 0 0]}; 
while ~isDone(hVideoSrc) 
    RGB = step(hVideoSrc);

    % 选择输入视频的下部（限制视野）
    Imlow  = RGB(NumRows+1:end, :, :);

    % 边缘检测和Hough变换
    Imlow = rgb2gray(Imlow); % Convert RGB to intensity
    I = imfilter(Imlow, [-1 0 1], 'replicate','corr'); %imfilter函数：对任意类型数组或多维图像进行滤波

    % 设置饱和值为0到1之间
    I(I < 0) = 0;
    I(I > 1) = 1;

    th = multithresh(I); % 计算门槛
    [H, Theta, Rho] = hough(I > th);

    % 将角度制变量Theta转换成弧度制
    Theta = Theta * pi / 180;

    % 峰值检测
    H1 = H;
    % 删除H中满足下列条件的矩阵： theta < -78 deg and theta >= 78 deg
    H1(:, 1:12) = 0;
    H1(:, end-12:end) = 0;
    Idx1 = houghpeaks(H1, ExpLaneNum, 'NHoodSize', [301 81], 'Threshold', 1);
    Count1 = size(Idx1,1);

    % 根据峰值来选择Rhos和Thetas
    Line = [Rho(Idx1(:, 1)); Theta(Idx1(:, 2))];
    Enable = [ones(1,Count1) zeros(1, ExpLaneNum-Count1)];

    % 跟踪一组标记了的车道线
    [Rep_ref, Count_ref] = videolanematching(Rep_ref, Count_ref, ...
                                MaxLaneNum, ExpLaneNum, Enable, Line, ...
                                TrackThreshold, frameFound+frameLost);

    % 将极值点转换到笛卡尔坐标系
    Pts = step(hHoughLines1, Rep_ref(2,:), Rep_ref(1,:), Imlow);

    % 检测是否有向左或向右的车道偏离
    [TwoValidLanes, NumNormalDriving, TwoLanes, OutMsg] = ...
            videodeparturewarning(Pts, Imlow, MaxLaneNum, Count_ref, ...
                                   NumNormalDriving, OutMsg);
    % 输出信息的含义: 
        % 0 = 向右离开当前车道
        % 1 = 正常驾驶
        % 2 = 向左离开当前车道

    % 检测车道线的颜色和类别
    YCbCr  = rgb2ycbcr(double(RGB(NumRows+1:240, :, :)));
    ColorAndTypeIdx = videodetectcolorandtype(TwoLanes, YCbCr);
    % 变量ColorAndTypeIdx的含义:
        % 无效的颜色或类别 = int8(0); 
        % 黄虚线 = int8(1);
        % 黄实线 = int8(2);  
        % 白虚线 = int8(3);
        % 白实线 = int8(4).

    % 输出
    Frame = Frame + 1;
    if Frame >= 5
        TwoLanes1 = TwoLanes + [offset; offset]';
        if DrawPoly && TwoValidLanes
            if TwoLanes(4,1) >= 239
                Templ = TwoLanes1(3:4, 1);
            else
                Templ = [0 239]';
            end
            if TwoLanes(4,2) >= 239
                Tempr = TwoLanes1(3:4, 2);
            else
                Tempr = [359 239]';
            end
            Pts_poly = [TwoLanes1(:,1); Templ; Tempr; ...
                TwoLanes1(3:4,2); TwoLanes1(1:2,2)];

            % 在车道区域绘制多边形
            RGB = insertShape(RGB,'FilledPolygon',Pts_poly.',...
                              'Color',[0 1 1],'Opacity',0.2);            
        end

        % 绘制车道线
        RGB = insertShape(RGB,'Line',TwoLanes1',...
            'Color',{'yellow','magenta'});
        % 插入车道变更警告文本 (空文本不会被绘制)
        txt = warnText{OutMsg+1};
        txtLoc = warnTextLoc(OutMsg+1, :);
        txtColor = single(warningTextColors{mod(Frame-1,4)+1});
        RGB = insertText(RGB,txtLoc,txt,'TextColor', txtColor, ...
                            'FontSize',20, 'BoxOpacity', 0);

        % 插入描述车道线的颜色和种类信息的文本
        for ii=1:2
            % 空文本不会被绘制
           txtLoc = TwoLanes1([1 2], ii)' + int32([0 -35]);
           lineTxt = lineText{ColorAndTypeIdx(ii)};
           txtColor = LaneColors(ColorAndTypeIdx(ii), :);
           RGB = insertText(RGB,txtLoc,lineTxt,'TextColor',txtColor, ...
                              'FontSize',14, 'BoxOpacity', 0);
        end

        % 如果有必要，绘制第三条车道线
        if OutMsgPre ~= OutMsg
            ColorType = ColorAndTypeIdx(2-(OutMsg == 2));
            Broken    = ColorType == 2 || ColorType == 4;
        end
        ShowThirdLane = Broken && (OutMsg~=1);
        if ShowThirdLane
            if OutMsg == 0
                % 寻找位于右边的第三条车道线
                Idx2 = houghpeaks(H(startIdxRho_R:startIdxRho_R+NumRhos_R-1, ...
                           startIdxTheta_R:startIdxTheta_R+NumThetas_R-1), ...
                           'NHoodSize', [7 7], 'Threshold', 1);
                Rhor = Rho(Idx2(:,1) + startIdxRho_R);
                Thetar = Theta(Idx2(:,2) + startIdxTheta_R);
                ThirdLane = step(hHoughLines3, Thetar, Rhor, Imlow);
            else
                % 寻找位于左边的第三条车道线
                Idx3 = houghpeaks(H(startIdxRho_L:startIdxRho_L+NumRhos_L-1 , ...
                           startIdxTheta_L:startIdxTheta_L+NumThetas_L-1),...
                            'NHoodSize', [7 7], 'Threshold', 1);
                Rhol = Rho(Idx3(:,1) + startIdxRho_L);
                Thetal = Theta(Idx3(:,2) + startIdxTheta_L);
                ThirdLane = step(hHoughLines3, Thetal, Rhol, Imlow);
            end

            OutThirdLane = videoexclude3rdlane(ThirdLane, ShowThirdLane,...
                                   TwoLanes, TwoValidLanes, YCbCr);  
            OutThirdLane = OutThirdLane(:) + offset(:);
            RGB = insertShape(RGB,'Line',OutThirdLane.','Color','green');           
        end
    end
    OutMsgPre = OutMsg;

    step(myVideoOut, RGB);    % 显示视频
end

运行截图：

代码获取链接：基于Matlab的车道线检测系统