emguCv3.x 实现字符分割，轮廓检测

 /// <summary>
        /// 获取区域
        /// </summary>
        /// <param name="bitmap"></param>
        /// <param name="graybtm"></param>
        /// <returns></returns>
        public static Bitmap FindBundingBox(Bitmap bitmap, out Bitmap graybtm,out List<Rectangle> rects)
        {
            Image<Bgr, byte> img = new Image<Bgr, byte>(bitmap);
            Image<Gray, byte> gray = new Image<Gray, byte>(img.Width, img.Height);
            Image<Bgr, byte> resuImage = new Image<Bgr, byte>(img.Width, img.Height);
            Image<Gray, byte> dnc = new Image<Gray, byte>(img.Width, img.Height);
            CvInvoke.CvtColor(img, gray, ColorConversion.Bgra2Gray);//灰度化
            //做一下膨胀，x与y方向都做，但系数不同
            var kernal = CvInvoke.GetStructuringElement(ElementShape.Rectangle, new Size(4, 4), new Point(1, 1));
            CvInvoke.Erode(gray, gray, kernal, new Point(0, 2), 1, BorderType.Default, new MCvScalar());
            //CvInvoke.Canny(gray, gray, 100, 60);
            CvInvoke.Threshold(gray, gray, 100, 255, ThresholdType.BinaryInv | ThresholdType.Otsu);//二值化
            //检测连通域，每一个连通域以一系列的点表示，FindContours方法只能得到第一个域
            graybtm = gray.ToBitmap();
            VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
            CvInvoke.FindContours(gray, contours, dnc, RetrType.Ccomp, ChainApproxMethod.ChainApproxSimple);
            var color = new MCvScalar(0, 0, 255);
            Console.WriteLine(contours.Size);
             rects = new List<Rectangle>();
            //开始遍历
            for (int i = 0; i < contours.Size; i++)
            {
                //得到这个连通区域的外接矩形
                var rect = CvInvoke.BoundingRectangle(contours[i]);
                //如果高度不足，或者长宽比太小，认为是无效数据，否则把矩形画到原图上
                if (rect.Height > 2 && rect.Width > 2)
                {
                    rects.Add(rect);
                    CvInvoke.DrawContours(resuImage, contours, i, color);
                }
            }

            return img.ConcateVertical(resuImage).ToBitmap();
        }

 private void StandardRects()
        {
            List<Rectangle> removeList=new List<Rectangle>();
            foreach (var item in glbRect)
            {
                if (glbRect.Exists(o => o.Contains(item) && o!=item))
                {
                    removeList.Add(item);
                }
            }
            glbRect.RemoveAll(o => removeList.Contains(o));
            glbRect=glbRect.OrderBy(o => o.X).ToList();
            lb_count.Text = "轮廓总数：" + glbRect.Count;
        }