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;
}