org.openimaj.feature

Enum ShortFVComparison

java.lang.Object

java.lang.Enum<ShortFVComparison>

org.openimaj.feature.ShortFVComparison

All Implemented Interfaces:

Serializable, Comparable<ShortFVComparison>, FVComparator<ShortFV>, ShortFVComparator, DistanceComparator<ShortFV>

public enum ShortFVComparison
extends Enum<ShortFVComparison>
implements ShortFVComparator

Comparison/distance methods for ShortFV objects.

Author:

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

Enum Constant Summary

Enum Constants

Enum Constant and Description
ARCCOS The arccosine of the cosine similarity
BHATTACHARYYA Bhattacharyya distance d(H1,H2) = sqrt( 1 - (1 / sqrt(sumI(H1(I)) * sumI(H2(I))) ) * sumI( sqrt(H1(I) * H2(I)) ) )
CHI_SQUARE Chi-squared distance d(H1,H2) = 0.5 * sumI[(H1(I)-H2(I))^2 / (H1(I)+H2(I))]
CITY_BLOCK City-block (L1) distance d(H1,H2) = sumI( abs(H1(I)-H2(I)) )
CORRELATION Correlation d(H1,H2) = sumI( H'1(I) * H'2(I) ) / sqrt( sumI[H'1(I)2]^2 * sumI[H'2(I)^2] ) where H'k(I) = Hk(I) - (1/N) * sumJ( Hk(J) ); N=number of FeatureVector bins
COSINE_DIST Cosine distance (-COSINE_SIM)
COSINE_SIM Cosine similarity (sim of 1 means identical) d(H1,H2)=sumI(H1(I) * H2(I))) / (sumI(H1(I)^2) sumI(H2(I)^2))
EUCLIDEAN Euclidean distance d(H1,H2) = Math.sqrt( sumI( (H1(I)-H2(I))^2 ) )
HAMMING Hamming Distance d(H1,H2) = sumI(H1(I) == H2(I) ? 1 : 0)
INTERSECTION Histogram intersection d(H1,H2) = sumI( min(H1(I), H2(I)) )
JACCARD_DISTANCE Jaccard distance.
PACKED_HAMMING Hamming Distance for packed bit strings d(H1,H2) = sumI(H1(I) == H2(I) ? 1 : 0)
SUM_SQUARE Sum-square distance d(H1,H2) = sumI( (H1(I)-H2(I))^2 )
SYMMETRIC_KL_DIVERGENCE The symmetric Kullback-Leibler divergence.

Method Summary

Methods

Modifier and Type	Method and Description
abstract double	compare(short[] h1, short[] h2) Compare two feature vectors in the form of native arrays, returning a score or distance.
double	compare(ShortFV h1, ShortFV h2) Compare two objects, returning a score or distance.
boolean	isDistance()
static ShortFVComparison	valueOf(String name) Returns the enum constant of this type with the specified name.
static ShortFVComparison[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

EUCLIDEAN

public static final ShortFVComparison EUCLIDEAN

Euclidean distance d(H1,H2) = Math.sqrt( sumI( (H1(I)-H2(I))^2 ) )

SUM_SQUARE

public static final ShortFVComparison SUM_SQUARE

Sum-square distance d(H1,H2) = sumI( (H1(I)-H2(I))^2 )

CORRELATION

public static final ShortFVComparison CORRELATION

Correlation d(H1,H2) = sumI( H'1(I) * H'2(I) ) / sqrt( sumI[H'1(I)2]^2 * sumI[H'2(I)^2] ) where H'k(I) = Hk(I) - (1/N) * sumJ( Hk(J) ); N=number of FeatureVector bins

CHI_SQUARE

public static final ShortFVComparison CHI_SQUARE

Chi-squared distance d(H1,H2) = 0.5 * sumI[(H1(I)-H2(I))^2 / (H1(I)+H2(I))]

INTERSECTION

public static final ShortFVComparison INTERSECTION

Histogram intersection d(H1,H2) = sumI( min(H1(I), H2(I)) )

BHATTACHARYYA

public static final ShortFVComparison BHATTACHARYYA

Bhattacharyya distance d(H1,H2) = sqrt( 1 - (1 / sqrt(sumI(H1(I)) * sumI(H2(I))) ) * sumI( sqrt(H1(I) * H2(I)) ) )

HAMMING

public static final ShortFVComparison HAMMING

Hamming Distance d(H1,H2) = sumI(H1(I) == H2(I) ? 1 : 0)

PACKED_HAMMING

public static final ShortFVComparison PACKED_HAMMING

Hamming Distance for packed bit strings d(H1,H2) = sumI(H1(I) == H2(I) ? 1 : 0)

CITY_BLOCK

public static final ShortFVComparison CITY_BLOCK

City-block (L1) distance d(H1,H2) = sumI( abs(H1(I)-H2(I)) )

COSINE_SIM

public static final ShortFVComparison COSINE_SIM

Cosine similarity (sim of 1 means identical) d(H1,H2)=sumI(H1(I) * H2(I))) / (sumI(H1(I)^2) sumI(H2(I)^2))

COSINE_DIST

public static final ShortFVComparison COSINE_DIST

Cosine distance (-COSINE_SIM)

ARCCOS

public static final ShortFVComparison ARCCOS

The arccosine of the cosine similarity

SYMMETRIC_KL_DIVERGENCE

public static final ShortFVComparison SYMMETRIC_KL_DIVERGENCE

The symmetric Kullback-Leibler divergence. Vectors must only contain positive values; internally they will be converted to double arrays and normalised to sum to unit length.

JACCARD_DISTANCE

public static final ShortFVComparison JACCARD_DISTANCE

Jaccard distance. Converts each vector to a set for comparison.

Method Detail

values

public static ShortFVComparison[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (ShortFVComparison c : ShortFVComparison.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static ShortFVComparison valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

isDistance

public boolean isDistance()

Specified by:

isDistance in interface DistanceComparator<ShortFV>

Returns:

true if the comparison is a distance; false if similarity.

compare

public double compare(ShortFV h1,
             ShortFV h2)

Description copied from interface: DistanceComparator

Compare two objects, returning a score or distance.

Specified by:

compare in interface DistanceComparator<ShortFV>

Parameters:

h1 - the first object

h2 - the second object

Returns:

a score or distance

compare

public abstract double compare(short[] h1,
             short[] h2)

Compare two feature vectors in the form of native arrays, returning a score or distance.

Specified by:

compare in interface ShortFVComparator

Parameters:

h1 - the first feature array

h2 - the second feature array

Returns:

a score or distance