HarrisCornersDetector Class
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HarrisCornersDetector Class

Harris Corners Detector.
Inheritance Hierarchy
SystemObject
  Accord.ImagingBaseFeatureExtractorCornerFeaturePoint
    Accord.ImagingBaseSparseFeatureExtractorCornerFeaturePoint
      Accord.ImagingBaseCornersDetector
        Accord.ImagingHarrisCornersDetector

Namespace:  Accord.Imaging
Assembly:  Accord.Imaging (in Accord.Imaging.dll) Version: 3.8.0
Syntax
public class HarrisCornersDetector : BaseCornersDetector
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The HarrisCornersDetector type exposes the following members.

Constructors
  NameDescription
Public methodHarrisCornersDetector
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(Single)
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(HarrisCornerMeasure)
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(Single, Single)
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(HarrisCornerMeasure, Single)
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(Single, Single, Double)
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(HarrisCornerMeasure, Single, Double)
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(Single, Single, Double, Int32)
Initializes a new instance of the HarrisCornersDetector class.
Public methodHarrisCornersDetector(HarrisCornerMeasure, Single, Double, Int32)
Initializes a new instance of the HarrisCornersDetector class.
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Properties
  NameDescription
Public propertyK
Harris parameter k. Default value is 0.04.
Public propertyMeasure
Gets or sets the measure to use when detecting corners.
Public propertyNumberOfInputs
Returns -1.
(Inherited from BaseFeatureExtractorTFeature.)
Public propertyNumberOfOutputs
Gets the dimensionality of the features generated by this extractor.
(Inherited from BaseFeatureExtractorTFeature.)
Public propertySigma
Gaussian smoothing sigma. Default value is 1.2.
Public propertySupportedFormats
Gets the list of image pixel formats that are supported by this extractor. The extractor will check whether the pixel format of any provided images are in this list to determine whether the image can be processed or not.
(Inherited from BaseFeatureExtractorTFeature.)
Public propertySuppression
Non-maximum suppression window radius. Default value is 3.
Public propertyThreshold
Harris threshold. Default value is 20000.
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Methods
  NameDescription
Public methodClone
Creates a new object that is a copy of the current instance.
(Inherited from BaseFeatureExtractorTFeature.)
Protected methodClone(ISetPixelFormat)
Creates a new object that is a copy of the current instance.
(Overrides BaseFeatureExtractorTFeatureClone(ISetPixelFormat).)
Public methodDispose
Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
(Inherited from BaseFeatureExtractorTFeature.)
Protected methodDispose(Boolean)
Releases unmanaged and - optionally - managed resources.
(Inherited from BaseFeatureExtractorTFeature.)
Public methodEquals
Determines whether the specified object is equal to the current object.
(Inherited from Object.)
Protected methodFinalize
Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetHashCode
Serves as the default hash function.
(Inherited from Object.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Protected methodInnerProcess
This method should be implemented by inheriting classes to implement the actual corners detection, transforming the input image into a list of points.
(Overrides BaseCornersDetectorInnerProcess(UnmanagedImage).)
Protected methodInnerTransform
This method should be implemented by inheriting classes to implement the actual feature extraction, transforming the input image into a list of features.
(Inherited from BaseCornersDetector.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodProcessImage(Bitmap)
Process image looking for corners.
(Inherited from BaseCornersDetector.)
Public methodProcessImage(BitmapData)
Process image looking for corners.
(Inherited from BaseCornersDetector.)
Public methodProcessImage(UnmanagedImage)
Process image looking for corners.
(Inherited from BaseCornersDetector.)
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
Public methodTransform(Bitmap)
Applies the transformation to an input, producing an associated output.
(Inherited from BaseFeatureExtractorTFeature.)
Public methodTransform(Bitmap)
Applies the transformation to an input, producing an associated output.
(Inherited from BaseFeatureExtractorTFeature.)
Public methodTransform(UnmanagedImage)
Applies the transformation to an input, producing an associated output.
(Inherited from BaseFeatureExtractorTFeature.)
Public methodTransform(UnmanagedImage)
Applies the transformation to an input, producing an associated output.
(Inherited from BaseFeatureExtractorTFeature.)
Public methodTransform(Bitmap, IEnumerableTFeature)
Applies the transformation to a set of input vectors, producing an associated set of output vectors.
(Inherited from BaseFeatureExtractorTFeature.)
Public methodTransform(UnmanagedImage, IEnumerableTFeature)
Applies the transformation to a set of input vectors, producing an associated set of output vectors.
(Inherited from BaseFeatureExtractorTFeature.)
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Extension Methods
  NameDescription
Public Extension MethodHasMethod
Checks whether an object implements a method with the given name.
(Defined by ExtensionMethods.)
Public Extension MethodIsEqual
Compares two objects for equality, performing an elementwise comparison if the elements are vectors or matrices.
(Defined by Matrix.)
Public Extension MethodTo(Type)Overloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
Public Extension MethodToTOverloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
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Remarks

This class implements the Harris corners detector.

Sample usage:

// create corners detector's instance
HarrisCornersDetector hcd = new HarrisCornersDetector( );
// process image searching for corners
Point[] corners = hcd.ProcessImage( image );
// process points
foreach ( Point corner in corners )
{
    // ... 
}

References:

  • P. D. Kovesi. MATLAB and Octave Functions for Computer Vision and Image Processing. School of Computer Science and Software Engineering, The University of Western Australia. Available in: http://www.csse.uwa.edu.au/~pk/Research/MatlabFns/Spatial/harris.m
  • C.G. Harris and M.J. Stephens. "A combined corner and edge detector", Proceedings Fourth Alvey Vision Conference, Manchester. pp 147-151, 1988.
  • Alison Noble, "Descriptions of Image Surfaces", PhD thesis, Department of Engineering Science, Oxford University 1989, p45.

See Also