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HuMoments Class
Hu's set of invariant image moments.
Inheritance Hierarchy
SystemObject
  Accord.Imaging.MomentsMomentsBase
    Accord.Imaging.MomentsHuMoments

Namespace:  Accord.Imaging.Moments
Assembly:  Accord.Imaging (in Accord.Imaging.dll) Version: 3.8.0
Syntax
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public class HuMoments : MomentsBase, IMoments
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The HuMoments type exposes the following members.

Constructors
  NameDescription
Public methodHuMoments(Int32)
Initializes a new instance of the HuMoments class.
Public methodHuMoments(Bitmap, Int32)
Initializes a new instance of the HuMoments class.
Public methodHuMoments(Single, Int32)
Initializes a new instance of the HuMoments class.
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Properties
  NameDescription
Public propertyI1
Hu moment of order 1.
Public propertyI2
Hu moment of order 2.
Public propertyI3
Hu moment of order 3.
Public propertyI4
Hu moment of order 4.
Public propertyI5
Hu moment of order 5.
Public propertyI6
Hu moment of order 6.
Public propertyI7
Hu moment of order 7.
Public propertyOrder
Gets or sets the maximum order of the moments.
(Inherited from MomentsBase.)
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Methods
  NameDescription
Public methodCompute(Bitmap)
Computes the moments for the specified image.
(Inherited from MomentsBase.)
Public methodCompute(BitmapData)
Computes the moments for the specified image.
(Inherited from MomentsBase.)
Public methodCompute(CentralMoments)
Computes the Hu moments from the specified central moments.
Public methodCompute(UnmanagedImage)
Computes the moments for the specified image.
(Inherited from MomentsBase.)
Public methodCompute(Single, Rectangle)
Computes the center moments for the specified image.
(Overrides MomentsBaseCompute(Single, Rectangle).)
Public methodCompute(Bitmap, Rectangle)
Computes the moments for the specified image.
(Inherited from MomentsBase.)
Public methodCompute(BitmapData, Rectangle)
Computes the moments for the specified image.
(Inherited from MomentsBase.)
Public methodCompute(UnmanagedImage, Rectangle)
Computes the center moments for the specified image.
(Overrides MomentsBaseCompute(UnmanagedImage, Rectangle).)
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 methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
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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

In image processing, computer vision and related fields, an image moment is a certain particular weighted average (moment) of the image pixels' intensities, or a function of such moments, usually chosen to have some attractive property or interpretation.

Image moments are useful to describe objects after segmentation. Simple properties of the image which are found via image moments include area (or total intensity), its centroid, and information about its orientation.

Hu's set of invariant moments are invariant under translation, changes in scale, and also rotation. The first moment, I1, is analogous to the moment of inertia around the image's centroid, where the pixels' intensities are analogous to physical density. The last one, I7, is skew invariant, which enables it to distinguish mirror images of otherwise identical images.

References:

  • Wikipedia contributors. "Image moment." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia. Available at http://en.wikipedia.org/wiki/Image_moment

Examples
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Bitmap image = ...;

// Compute the Hu moments of up to third order
HuMoments hu = new HuMoments(image, order: 3);
See Also