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CvInvokeHoughCircles Method (IInputArray, HoughType, Double, Double, Double, Double, Int32, Int32)
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Finds circles in a grayscale image using the Hough transform

Namespace: Emgu.CV
Assembly: Emgu.CV.World (in Emgu.CV.World.dll) Version: 3.1.0.2282 (3.1.0.2282)
Syntax
public static CircleF[] HoughCircles(
	IInputArray image,
	HoughType method,
	double dp,
	double minDist,
	double param1 = 100,
	double param2 = 100,
	int minRadius = 0,
	int maxRadius = 0
)

Parameters

image
Type: Emgu.CVIInputArray
8-bit, single-channel, grayscale input image.
method
Type: Emgu.CV.CvEnumHoughType
Detection method to use. Currently, the only implemented method is CV_HOUGH_GRADIENT , which is basically 21HT
dp
Type: SystemDouble
Inverse ratio of the accumulator resolution to the image resolution. For example, if dp=1 , the accumulator has the same resolution as the input image. If dp=2 , the accumulator has half as big width and height.
minDist
Type: SystemDouble
Minimum distance between the centers of the detected circles. If the parameter is too small, multiple neighbor circles may be falsely detected in addition to a true one. If it is too large, some circles may be missed.
param1 (Optional)
Type: SystemDouble
First method-specific parameter. In case of CV_HOUGH_GRADIENT , it is the higher threshold of the two passed to the Canny() edge detector (the lower one is twice smaller).
param2 (Optional)
Type: SystemDouble
Second method-specific parameter. In case of CV_HOUGH_GRADIENT , it is the accumulator threshold for the circle centers at the detection stage. The smaller it is, the more false circles may be detected. Circles, corresponding to the larger accumulator values, will be returned first.
minRadius (Optional)
Type: SystemInt32
Minimum circle radius.
maxRadius (Optional)
Type: SystemInt32
Maximum circle radius.

Return Value

Type: CircleF
The circles detected
See Also