Keypoint (The OpenIMAJ Local Image Features Library 1.3.9 API)

java.lang.Object
- org.openimaj.image.feature.local.keypoints.Keypoint

All Implemented Interfaces:

Serializable, Cloneable, FeatureVectorProvider<ByteFV>, LocalFeature<KeypointLocation,ByteFV>, LocalFeatureVectorProvider<KeypointLocation,ByteFV>, LocationProvider<KeypointLocation>, Readable, ReadableASCII, ReadableBinary, ReadWriteable, VariableLength, Writeable, WriteableASCII, WriteableBinary, Coordinate, Point2d, ScaleSpacePoint

Direct Known Subclasses:

AffineSimulationKeypoint, InterestPointKeypoint, MinMaxKeypoint
```
public class Keypoint
extends Object
implements Serializable, ScaleSpacePoint, LocalFeature<KeypointLocation,ByteFV>, VariableLength, Cloneable
```
A local interest point with a location, scale, orientation and associated feature. The feature is stored as an array of bytes.

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`byte[]`	`ivec` keypoint feature descriptor (i.e.
`float`	`ori` dominant orientation of keypoint
`float`	`scale` scale of keypoint
`float`	`x` x-position of keypoint
`float`	`y` y-position of keypoint

Constructor Summary

Constructors
Constructor and Description
`Keypoint()` Construct with the default feature vector length for SIFT (128).
`Keypoint(float x, float y, float ori, float scale, byte[] ivec)` Construct with the given parameters.
`Keypoint(int length)` Construct with the given feature vector length.
`Keypoint(Keypoint k)` Construct by copying from another `Keypoint`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static List<Keypoint>`	`addGaussianNoise(List<Keypoint> siftFeatures, double mean, double sigma)` Add Gaussian noise the feature vectors of some features.
`String`	`asciiHeader()`
`byte[]`	`binaryHeader()`
`Keypoint`	`clone()`
`Point2d`	`copy()`
`void`	`copyFrom(Point2d p)`
`boolean`	`equals(Object obj)`
`int`	`getDimensions()`
`ByteFV`	`getFeatureVector()`
`KeypointLocation`	`getLocation()`
`Float`	`getOrdinate(int dimension)`
`static List<Keypoint>`	`getRelativeKeypoints(List<Keypoint> keypoints, float x, float y)` Create a list of `Keypoint`s from the input list, but with the positions offset by the given amount.
`float`	`getScale()`
`static List<Keypoint>`	`getScaledKeypoints(List<Keypoint> keypoints, int toScale)` Scale a list of keypoints by the given amount.
`float`	`getX()`
`float`	`getY()`
`int`	`hashCode()`
`boolean`	`locationEquals(Object obj)` Test whether the location of this `Keypoint` and another `Keypoint` is the same.
`Point2d`	`minus(Point2d a)`
`void`	`readASCII(Scanner in)`
`void`	`readBinary(DataInput in)`
`void`	`setLocation(KeypointLocation location)` Set the location of this `Keypoint`
`void`	`setOrdinate(int dimension, Number value)`
`void`	`setScale(float scale)`
`void`	`setX(float x)`
`void`	`setY(float y)`
`String`	`toString()`
`Keypoint`	`transform(Jama.Matrix transform)`
`void`	`translate(float x, float y)`
`void`	`translate(Point2d v)`
`void`	`writeASCII(PrintWriter out)`
`void`	`writeBinary(DataOutput out)`

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - ivec
```
public byte[] ivec
```
    keypoint feature descriptor (i.e. SIFT)
  - ori
```
public float ori
```
    dominant orientation of keypoint
  - scale
```
public float scale
```
    scale of keypoint
  - x
```
public float x
```
    x-position of keypoint
  - y
```
public float y
```
    y-position of keypoint
- Constructor Detail
  - Keypoint
```
public Keypoint()
```
    Construct with the default feature vector length for SIFT (128).
  - Keypoint
```
public Keypoint(int length)
```
    Construct with the given feature vector length.
    
    Parameters:
    
    length - the length of the feature vector
  - Keypoint
```
public Keypoint(float x,
                float y,
                float ori,
                float scale,
                byte[] ivec)
```
    Construct with the given parameters.
    
    Parameters:
    
    x - the x-ordinate of the keypoint
    
    y - the y-ordinate of the keypoint
    
    ori - the orientation of the keypoint
    
    scale - the scale of the keypoint
    
    ivec - the feature vector of the keypoint
  - Keypoint
```
public Keypoint(Keypoint k)
```
    Construct by copying from another Keypoint
    
    Parameters:
    
    k - the Keypoint to copy from
- Method Detail
  - getOrdinate
```
public Float getOrdinate(int dimension)
```
    Specified by:
    
    getOrdinate in interface Coordinate
  - getDimensions
```
public int getDimensions()
```
    Specified by:
    
    getDimensions in interface Coordinate
  - getX
```
public float getX()
```
    Specified by:
    
    getX in interface Point2d
  - getY
```
public float getY()
```
    Specified by:
    
    getY in interface Point2d
  - setX
```
public void setX(float x)
```
    Specified by:
    
    setX in interface Point2d
  - setY
```
public void setY(float y)
```
    Specified by:
    
    setY in interface Point2d
  - getScale
```
public float getScale()
```
    Specified by:
    
    getScale in interface ScaleSpacePoint
  - setScale
```
public void setScale(float scale)
```
    Specified by:
    
    setScale in interface ScaleSpacePoint
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - locationEquals
```
public boolean locationEquals(Object obj)
```
    Test whether the location of this Keypoint and another Keypoint is the same.
    
    Parameters:
    
    obj - the other keypoint
    
    Returns:
    
    true if the locations match; false otherwise.
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - clone
```
public Keypoint clone()
```
    Overrides:
    
    clone in class Object
  - copyFrom
```
public void copyFrom(Point2d p)
```
    Specified by:
    
    copyFrom in interface Point2d
  - writeBinary
```
public void writeBinary(DataOutput out)
                 throws IOException
```
    Specified by:
    
    writeBinary in interface WriteableBinary
    
    Throws:
    
    IOException
  - writeASCII
```
public void writeASCII(PrintWriter out)
                throws IOException
```
    Specified by:
    
    writeASCII in interface WriteableASCII
    
    Throws:
    
    IOException
  - readBinary
```
public void readBinary(DataInput in)
                throws IOException
```
    Specified by:
    
    readBinary in interface ReadableBinary
    
    Throws:
    
    IOException
  - readASCII
```
public void readASCII(Scanner in)
               throws IOException
```
    Specified by:
    
    readASCII in interface ReadableASCII
    
    Throws:
    
    IOException
  - binaryHeader
```
public byte[] binaryHeader()
```
    Specified by:
    
    binaryHeader in interface ReadableBinary
    
    Specified by:
    
    binaryHeader in interface WriteableBinary
  - asciiHeader
```
public String asciiHeader()
```
    Specified by:
    
    asciiHeader in interface ReadableASCII
    
    Specified by:
    
    asciiHeader in interface WriteableASCII
  - getFeatureVector
```
public ByteFV getFeatureVector()
```
    Specified by:
    
    getFeatureVector in interface FeatureVectorProvider<ByteFV>
  - getLocation
```
public KeypointLocation getLocation()
```
    Specified by:
    
    getLocation in interface LocationProvider<KeypointLocation>
  - setLocation
```
public void setLocation(KeypointLocation location)
```
    Set the location of this Keypoint
    
    Parameters:
    
    location - the location
  - getRelativeKeypoints
```
public static List<Keypoint> getRelativeKeypoints(List<Keypoint> keypoints,
                                                  float x,
                                                  float y)
```
    Create a list of Keypoints from the input list, but with the positions offset by the given amount.
    
    Parameters:
    
    keypoints - the input list
    
    x - the x offset
    
    y - the y offset
    
    Returns:
    
    the new keypoints
  - addGaussianNoise
```
public static List<Keypoint> addGaussianNoise(List<Keypoint> siftFeatures,
                                              double mean,
                                              double sigma)
```
    Add Gaussian noise the feature vectors of some features. The original features are untouched; the returned list contains a copy.
    
    Parameters:
    
    siftFeatures - the input features
    
    mean - the mean of the noise
    
    sigma - the standard deviation of the noise
    
    Returns:
    
    the noisy keypoints
  - getScaledKeypoints
```
public static List<Keypoint> getScaledKeypoints(List<Keypoint> keypoints,
                                                int toScale)
```
    Scale a list of keypoints by the given amount. This scales the location and scale of each keypoint. The original features are untouched; the returned list contains a copy.
    
    Parameters:
    
    keypoints - the input features.
    
    toScale - the scale factor
    
    Returns:
    
    the scaled features.
  - translate
```
public void translate(float x,
                      float y)
```
    Specified by:
    
    translate in interface Point2d
  - transform
```
public Keypoint transform(Jama.Matrix transform)
```
    Specified by:
    
    transform in interface Point2d
  - minus
```
public Point2d minus(Point2d a)
```
    Specified by:
    
    minus in interface Point2d
  - translate
```
public void translate(Point2d v)
```
    Specified by:
    
    translate in interface Point2d
  - copy
```
public Point2d copy()
```
    Specified by:
    
    copy in interface Point2d
  - setOrdinate
```
public void setOrdinate(int dimension,
                        Number value)
```
    Specified by:
    
    setOrdinate in interface Coordinate

Class Keypoint

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ivec

ori

scale

x

y

Constructor Detail

Keypoint

Keypoint

Keypoint

Keypoint

Method Detail

getOrdinate

getDimensions

getX

getY

setX

setY

getScale

setScale

toString

locationEquals

equals

hashCode

clone

copyFrom

writeBinary

writeASCII

readBinary

readASCII

binaryHeader

asciiHeader

getFeatureVector

getLocation

setLocation

getRelativeKeypoints

addGaussianNoise

getScaledKeypoints

translate

transform

minus

translate

copy

setOrdinate