获取所有计数器的所有点emgu cv

Question

我想画一个旋转的矩形。 canny图像不是一个计数器，它是一组计数器。所以我想要得到所有计数器的所有点。例如

Points[] pts = points of all counters. 

请参阅附加图片。

Answer 1

canny显示图像中的所有边缘，而不是外部轮廓。这是一种（但不是唯一的）做对象检测（前景/背景提取）的方法。 以下片段通过使用canny边缘检测器提取对象roi（Min area Rect）。从otsu阈值开始的canny thresh参数的carrefull。

希望它有帮助。 Detection result

Image<Gray,byte> imageFullSize = new Image<Gray, byte>(imagePath); 
Rectangle roi = new Rectangle(Your Top Left X,Your Top Left Y,Your ROI Width,Your ROI Height); 
//Now get a roi (No copy, it is a new header pointing original image 
Image<Gray,byte> image = imageFullSize.GetSubRect(roi); 
//Step 1 : contour detection using canny 
//Gaussian noise removal, eliminate background false détections 
image._SmoothGaussian(15); 
//Canny thresh based on otsu threshold value: 
Mat binary = new Mat(); 
double otsuThresh = CvInvoke.Threshold(image, binary, 0, 255, ThresholdType.Binary | ThresholdType.Otsu); 
double highThresh = otsuThresh; 
double lowThresh = otsuThresh * 0.5; 
var cannyImage = image.Canny(lowThresh, highThresh); 
//Step 2 : contour extraction 
Mat hierarchy=new Mat(); 
VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint(); 
CvInvoke.FindContours(cannyImage,contours,hierarchy,RetrType.External,ChainApproxMethod.ChainApproxSimple); 
//Step 3 : contour fusion 
List<Point> points=new List<Point>(); 
for(int i = 0; i < contours.Size; i++) 
{ 
    points.AddRange(contours[i].ToArray()); 
} 

//Step 4 : Rotated rect 
RotatedRect minAreaRect = CvInvoke.MinAreaRect(points.Select(pt=>new PointF(pt.X,pt.Y)).ToArray()); 
Point[] vertices = minAreaRect.GetVertices().Select(pt => new Point((int)pt.X, (int)pt.Y)).ToArray(); 
//Step 5 : draw result 
Image <Bgr,byte > colorImageFullSize =new Image<Bgr, byte>(imagePath); 
Image <Bgr,byte > colorImage =colorImageFullSize.GetSubRect(roi); 
colorImage.Draw(vertices,new Bgr(Color.Red),2);