org.openimaj.feature.local.filter

Class ByteEntropyFilter

java.lang.Object

org.openimaj.feature.local.filter.ByteEntropyFilter

All Implemented Interfaces:

Predicate<LocalFeature<?,ByteFV>>

@Reference(author={"Wei Dong","Zhe Wang","Kai Li"},
           title="High-Confidence Near-Duplicate Image Detection",
           type=Inproceedings,
           year="2012",
           booktitle="ACM International Conference on Multimedia Retrieval",
           customData={"location","Hong Kong, China"})
public class ByteEntropyFilter
extends Object
implements Predicate<LocalFeature<?,ByteFV>>

Filter LocalFeatures typed on ByteFV by rejecting those that have a low feature entropy. Such features are those that tend to have little variation; for example, in the case of SIFT features, the removed features are typically the ones that mismatch easily.

This filter is an implementation of the approach described by Dong, Wang and Li; the default threshold is taken from the paper, and will work with standard SIFT features, such as those produced by a DoGSIFTEngine.

Author:

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

Constructor Summary

Constructors

Constructor and Description
ByteEntropyFilter() Construct with the default threshold of 4.4 as suggested in the original paper.
ByteEntropyFilter(double threshold) Construct with a custom threshold.

Method Summary

Methods

Modifier and Type	Method and Description
static double	entropy(byte[] vector) Compute the entropy of the given byte vector.
boolean	test(LocalFeature<?,ByteFV> object) Tests whether a specific object passes some criteria.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ByteEntropyFilter

public ByteEntropyFilter()

Construct with the default threshold of 4.4 as suggested in the original paper.

ByteEntropyFilter

public ByteEntropyFilter(double threshold)

Construct with a custom threshold.

Parameters:

threshold - The threshold.

Method Detail

test

public boolean test(LocalFeature<?,ByteFV> object)

Description copied from interface: Predicate

Tests whether a specific object passes some criteria.

Specified by:

test in interface Predicate<LocalFeature<?,ByteFV>>

Parameters:

object - the object being tested.

Returns:

true if object passes the criteria; false otherwise.

entropy

public static double entropy(byte[] vector)

Compute the entropy of the given byte vector.

Parameters:

vector - the vector.

Returns:

the entropy.