Merging lines after using houglinesp, C#

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C#

OpenCV

image-processing

My project is to detect the lines on a picture, I know using houghline function(openCVsharp), but the result gives me many parallel lines. Could you guide me on how to merge these parallel lines?

var gray = OpenCvSharp.Cv2.ImRead(filename, OpenCvSharp.ImreadModes.Grayscale);
var binary = gray.Threshold(0, 255, OpenCvSharp.ThresholdTypes.BinaryInv | OpenCvSharp.ThresholdTypes.Otsu);

var element = Cv2.GetStructuringElement(MorphShapes.Rect, new OpenCvSharp.Size(5, 5),
                            new OpenCvSharp.Point(-1, -1));

var Morp_out = new Mat();
Cv2.MorphologyEx(binary, Morp_out,MorphTypes.Open,element);        
        var Ero_out = new Mat();
Cv2.Erode(Morp_out, Ero_out, element);
        using (new Window("Erode Image", WindowMode.AutoSize, Ero_out))
        {
            Window.WaitKey(0);
        }
 var processed_img = Ero_out;
 double min_Line_length = 100;
 double max_line_gap = 10;
 double rho = 1;
 double theta = Math.PI / 180;
 int threshold = 100;
 LineSegmentPoint[] setH_P = Cv2.HoughLinesP(processed_img, rho, theta, threshold, min_Line_length, max_line_gap);
 Mat Img_outPut = processed_img.EmptyClone();
        foreach  (LineSegmentPoint s in setH_P)
        {
            Img_outPut.Line(s.P1, s.P2, Scalar.White, 1);
        }
 using (new Window("HoughLinesP", WindowMode.AutoSize, Img_outPut))
        {
            Window.WaitKey(0);
        }

What I have tried:

My idea is

compare all possible line segment pairs, then check the distance between all possible endpoints, then compare it with a threshold, and draw it. However, I do not have any experience with programming, so it is kind of difficult for me to implement it