C#：轮廓面积周长

一、程序

        private void uiButton11_Click(object sender, EventArgs e)
        {
            Mat src = src_img.Clone();
            // 如果背景色是白色，则需要进行此操作。即黑色变白色，白色变黑色。
            // 按位运算
            // opencv非运算不是1变0，0变1。而是 !x = 255 - x
            Cv2.BitwiseNot(src, src);
            // 高斯模糊
            Mat blur = new Mat();
            Cv2.GaussianBlur(src, blur, new OpenCvSharp.Size(15, 15), 0, 0);
            //Cv2.ImShow("滤波", blur);
            // 二值化
            Mat grayImg = new Mat();
            Mat binary = new Mat();
            Cv2.CvtColor(blur, grayImg, ColorConversionCodes.BGR2GRAY);
            Cv2.Threshold(grayImg, binary, 0, 255, ThresholdTypes.Binary | ThresholdTypes.Triangle);
            //Cv2.ImShow("二值化", binary);
            // 形态学操作
            Mat morphImage = new Mat();
            Mat kernel = Cv2.GetStructuringElement(MorphShapes.Rect, new OpenCvSharp.Size(3, 3), new OpenCvSharp.Point(-1, -1));
            Cv2.MorphologyEx(binary, morphImage, MorphTypes.Close, kernel, new OpenCvSharp.Point(-1, -1), 2);
            //Cv2.ImShow("形态学操作", morphImage);
            OpenCvSharp.Point[][] contours;
            HierarchyIndex[] hierarchies;
            // 寻找轮廓
            Cv2.FindContours(morphImage, out contours, out hierarchies, RetrievalModes.External, ContourApproximationModes.ApproxSimple, new OpenCvSharp.Point());

            Mat dest = Mat.Zeros(src.Size(), MatType.CV_8UC3);
            for (int i = 0; i < contours.Length; i++)
            {
                double area = Cv2.ContourArea(contours[i]);
                double len = Cv2.ArcLength(contours[i], true);
                Cv2.DrawContours(dest, contours, (int)i, new Scalar(0, 0, 255), 1, LineTypes.Link8, hierarchies);
                Cv2.PutText(dest, "area:" + area.ToString(""), new OpenCvSharp.Point(20, 50), HersheyFonts.HersheySimplex, 1, new Scalar(0, 255, 255), 1, LineTypes.Link4);
                Cv2.PutText(dest, "length:" + len.ToString("0.00"), new OpenCvSharp.Point(20, 150), HersheyFonts.HersheySimplex, 1, new Scalar(0, 255, 255), 1, LineTypes.Link4);
            }        
            pictureBox1.Image = dest.ToBitmap();
        }
    }

二、结果

三、资料

蒋智昊的博客
http://chanpinxue.cn/archives/5181.html