Halcon 十字抓取算法

原创已于 2022-07-19 09:35:19 修改 · 2.1k 阅读

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于 2019-12-23 21:59:48 首次发布

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本文介绍了Halcon中的十字线抓取算法，关键在于滤波阈值设定和线段处理。通过设置滤波高值和低值为24，以及十字线宽度为60，算法能有效拟合高斯直线，过滤掉小线段，并连接相邻线段。最终，对连接后的线进行过滤和拟合，实现精准的十字线检测。

在这里插入图片描述 ` [DisplayName(“滤波高值”)]
public int ThresholdHight { get; set; } = 24;
[DisplayName(“滤波低值”)]
public int ThresholdLow { get; set; } = 24;
[DisplayName(“十字线宽”)]
public int CrossLineWidth { get; set; } = 60;

    [DisplayName("是否显示轮廓")]
    public YesNo ShowOutline { get; set; } = true;
    [DisplayName("第一次过滤最短线长")]
    public int FristSelectLineShort { get; set; } = 255;
    [DisplayName("是否显示第一次过滤线长")]
    public YesNo ShowFristSelectXLD { get; set; } = true;

    [DisplayName("第二次过滤最短线长")]
    public int DoubleSelectLineShort { get; set; } = 500;
    [DisplayName("是否显示第二次过滤线长")]
    public YesNo ShowDoubleSelectXLD { get; set; } = true;

    public bool FindCross(out HObject contours)
    {
        if (!base.Execute())
        {
            contours = null;
            return false;
        }
        if (ImageProvider == null || !ImageProvider.Enabled || !ImageProvider.GetResult())
        {
            contours = null;
            return false;
        }
        // Initialize local and output iconic variables 
        HOperatorSet.GenEmptyObj(out HObject ho_Angio);
        HOperatorSet.GenEmptyObj(out HObject ho_GrayImage);
        HOperatorSet.GenEmptyObj(out HObject ho_Lines);
        HOperatorSet.GenEmptyObj(out HObject ho_RelLines);
        HOperatorSet.GenEmptyObj(out HObject ho_UnionContours);
        HOperatorSet.GenEmptyObj(out HObject ho_asd);

        HObject curImage = ImageProvider.GetCurrentImage();
        HOperatorSet.Rgb1ToGray(ho_Angio, out ho_GrayImage);

        //根据最大线宽和对比度计算lines_gauss的三个参数
        //第1个参数：最大线宽
        //第2个参数：对比度，若有2个值，第2个值为最小对比度且一定小于第1个值；若
        //仅有1个值，则最小对比度为最大对比度的1/3
        calculate_lines_gauss_parameters(CrossLineWidth, (new HTuple(ThresholdHight)).TupleConcat(ThresholdLow), out HTuple hv_Sigma,
            out HTuple hv_Low, out HTuple hv_High);
        //计算高斯直线
        ho_Lines.Dispose();
        HOperatorSet.LinesGauss(curImage, out ho_Lines, hv_Sigma, hv_Low, hv_High,
            "dark", "true", "parabolic", "true");
        //过滤固定线长的轮廓
        ho_RelLines.Dispose();
        HOperatorSet.SelectContoursXld(ho_Lines, out ho_RelLines, "length", FristSelectLineShort, 9999, 0, 0);
        if (ShowFristSelectXLD)
        {
            contours = ho_RelLines;
            Owner.Display.ShowObject(ho_RelLines);                
        }
        //将共线的轮廓连接起来
        ho_UnionContours.Dispose();
        HOperatorSet.UnionCollinearContoursXld(ho_RelLines, out ho_UnionContours, 1000, 1, 6, 0.1, "attr_keep");
        //过滤固定线长的轮廓
        ho_asd.Dispose();
        HOperatorSet.SelectContoursXld(ho_UnionContours, out ho_asd, "length", DoubleSelectLineShort, 9999, 0, 0);
        if (ShowDoubleSelectXLD)
        {contours = ho_RelLines;
            Owner.Display.ShowObject(ho_asd);
        }
        //拟合直线
        HOperatorSet.FitLineContourXld(ho_asd, "tukey", -1, 0, 5, 2, out HTuple hv_RowBegin,
            out HTuple hv_ColBegin, out HTuple hv_RowEnd, out HTuple hv_ColEnd, out HTuple hv_Nr, out HTuple hv_Nc, out HTuple hv_Dist);
        HOperatorSet.TupleLength(hv_ColBegin, out HTuple length);
        if (length != 2)//避免取到过多直线
        {
            contours = null;
            return false;
        }
        else
        {
            contours = ho_RelLines;
        }

        List<PointF> Points = new List<PointF>();
        for (int i = 0; i < 2; i++)
        {
            double ox1 = 0, oy1 = 0, ox2 = 0, oy3 = 0;
            imageProvider.ConvertXY(hv_ColBegin[i], hv_RowBegin[i], ref ox1, ref oy1);
            imageProvider.ConvertXY(hv_ColEnd[i], hv_RowEnd[i], ref ox2, ref oy3);
            PointF point = new PointF((float)ox1, (float)oy1);
            PointF point1 = new PointF((float)ox2, (float)oy3);
            Points.Add(point);
            Points.Add(point1);
        }
        PointF CrossPoint = GetIntersection(Points[0], Points[1], Points[2], Points[3]);

        SetRunDataDouble("Xstart1", Points[0].X);
        SetRunDataDouble("Ystart1", Points[0].Y);
        SetRunDataDouble("XEmd1", Points[1].X);
        SetRunDataDouble("YEmd1", Points[1].Y);


        SetRunDataDouble("Xstart2", Points[2].X);
        SetRunDataDouble("Ystart2", Points[2].Y);
        SetRunDataDouble("XEmd2", Points[3].X);
        SetRunDataDouble("YEmd2", Points[3].Y);

        SetRunDataDouble("X", CrossPoint.X);
        SetRunDataDouble("Y", CrossPoint.Y);
        if (ShowOutline)
        {
            Line l1 = new Line(hv_ColBegin[0], hv_RowBegin[0], hv_ColEnd[0], hv_RowEnd[0]);
            Line l2 = new Line(hv_ColBegin[1], hv_RowBegin[1], hv_ColEnd[1], hv_RowEnd[1]);
            //Line l1 = new Line(Points[0].X, Points[0].Y, Points[1].X, Points[1].Y);
            //Line l2 = new Line(Points[2].X, Points[2].Y, Points[3].X, Points[3].Y);
            Owner.Display.ShowLine(l1, "green", 1, 0.2);
            Owner.Display.ShowLine(l2, "green", 1, 0.2);
            //Owner.Display.ShowObject(ho_asd);
        }
        return true;
    }
    protected override bool Execute()
    {
        return FindCross(out HObject contours);
    }`

算法的重点在于高斯直线的拟合，过滤小线段，连接相临线段，过滤连接后的线，然后拟合线。

连接后的过滤可以过滤全部的小线段。