Package dev.brachtendorf.jimagehash.matcher

Class TypedImageMatcher

java.lang.Object

dev.brachtendorf.jimagehash.matcher.TypedImageMatcher

Direct Known Subclasses:

ConsecutiveMatcher, DatabaseImageMatcher, PersistentImageMatcher, SingleImageMatcher

public abstract class TypedImageMatcher
extends Object

Image matchers are a collection of classes which bundle the hashing operation of one or multiple HashingAlgorithms and expose functionalities to compare multiple images with each other.

TypedImageMatchers accept hashing algorithms with additional configuration details attached to each entry.

Author:

Kilian

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TypedImageMatcher.AlgoSettings	Settings used while computing if an algorithms consideres two images to be a close match

Field Summary

Fields

Modifier and Type	Field	Description
protected LinkedHashMap<HashingAlgorithm,TypedImageMatcher.AlgoSettings>	steps	Contains multiple hashing algorithms applied in the order they were added to the image matcher

Constructor Summary

Constructors

Constructor	Description
TypedImageMatcher()

Method Summary

Modifier and Type	Method	Description
void	addHashingAlgorithm(HashingAlgorithm algo, double threshold)	Append a new hashing algorithm which will be executed after all hash algorithms passed the test.
void	addHashingAlgorithm(HashingAlgorithm algo, double threshold, boolean normalized)	Append a new hashing algorithm which will be executed after all hash algorithms passed the test.
void	clearHashingAlgorithms()	Remove all hashing algorithms used by this image matcher instance.
boolean	equals(Object obj)
Map<HashingAlgorithm,TypedImageMatcher.AlgoSettings>	getAlgorithms()	Return an immutable map copy of the algorithms currently used in the matcher.
int	hashCode()
boolean	removeHashingAlgo(HashingAlgorithm algo)	Removes the hashing algorithms from the image matcher.

Methods inherited from class java.lang.Object

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

Field Detail

steps

protected LinkedHashMap<HashingAlgorithm,TypedImageMatcher.AlgoSettings> steps

Contains multiple hashing algorithms applied in the order they were added to the image matcher

Constructor Detail

TypedImageMatcher

public TypedImageMatcher()

Method Detail

addHashingAlgorithm

public void addHashingAlgorithm(HashingAlgorithm algo,
                                double threshold)

Append a new hashing algorithm which will be executed after all hash algorithms passed the test.

The same algorithm may only be added once. Attempts to add an identical algorithm will instead update the settings of the old instance.

This method assumes the normalized hamming distance. If the definite distance shall be used take a look at addHashingAlgorithm(HashingAlgorithm, double, boolean)

Parameters:

algo - The algorithms to be added

threshold - maximum normalized hamming distance between hashes in order to pass as identical image

addHashingAlgorithm

public void addHashingAlgorithm(HashingAlgorithm algo,
                                double threshold,
                                boolean normalized)

Append a new hashing algorithm which will be executed after all hash algorithms passed the test.

The same algorithm may only be added once to an image hasher. Attempts to add an identical algorithm will instead update the settings of the old instance.

Parameters:

algo - The algorithms to be added

threshold - the threshold the hamming distance may be in order to pass as identical image.

normalized - Weather the normalized or default hamming distance shall be used. The normalized hamming distance will be in range of [0-1] while the hamming distance depends on the length of the hash

removeHashingAlgo

public boolean removeHashingAlgo(HashingAlgorithm algo)

Removes the hashing algorithms from the image matcher.

Parameters:

algo - the algorithm to be removed

Returns:

true if the algorithms was removed, false otherwise

clearHashingAlgorithms

public void clearHashingAlgorithms()

Remove all hashing algorithms used by this image matcher instance. At least one algorithm has to be supplied before imaages can be checked for similarity

getAlgorithms

public Map<HashingAlgorithm,TypedImageMatcher.AlgoSettings> getAlgorithms()

Return an immutable map copy of the algorithms currently used in the matcher. This map is a hard copy of the hashmap and does not updated if the underlying collection gets altered

Returns:

A map containing all algorithms used in this matcher

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object