aliceVision::voctree::Database Class Reference

Class for efficiently matching a bag-of-words representation of a document (image) against a database of known documents. More...

#include <Database.hpp>

Public Member Functions
	Database (uint32_t num_words=0)
	Constructor. More...
DocId	insert (DocId doc_id, const SparseHistogram &document)
	Insert a new document. More...
void	sanityCheck (std::size_t N, std::map< std::size_t, DocMatches > &matches) const
	Perform a sanity check of the database by querying each document of the database and finding its top N matches. More...
void	find (const std::vector< Word > &document, std::size_t N, std::vector< DocMatch > &matches, const std::string &distanceMethod="strongCommonPoints") const
	Find the top N matches in the database for the query document. More...
void	find (const SparseHistogram &query, std::size_t N, std::vector< DocMatch > &matches, const std::string &distanceMethod="strongCommonPoints") const
	Find the top N matches in the database for the query document. More...
void	computeTfIdfWeights (float default_weight=1.0f)
	Compute the TF-IDF weights of all the words. To be called after inserting a corpus of training examples into the database. More...
std::size_t	size () const
	Return the size of the database in terms of number of documents. More...
void	saveWeights (const std::string &file) const
	Save the vocabulary word weights to a file.
void	loadWeights (const std::string &file)
	Load the vocabulary word weights from a file.
const SparseHistogramPerImage &	getSparseHistogramPerImage () const

Friends
std::ostream &	operator<< (std::ostream &os, const SparseHistogram &dv)

Detailed Description

Class for efficiently matching a bag-of-words representation of a document (image) against a database of known documents.

Constructor & Destructor Documentation

Database()

aliceVision::voctree::Database::Database ( uint32_t  num_words = 0 )

explicit

Constructor.

If computing weights for a new vocabulary, num_words should be the size of the vocabulary. If calling loadWeights(), it can be left zero.

Member Function Documentation

computeTfIdfWeights()

void aliceVision::voctree::Database::computeTfIdfWeights

(

float

default_weight = 1.0f

)

Compute the TF-IDF weights of all the words. To be called after inserting a corpus of training examples into the database.

Parameters

default_weight

The default weight of a word that appears in none of the training documents.

find() [1/2]

void aliceVision::voctree::Database::find	(	const SparseHistogram &	query,
		std::size_t	N,
		std::vector< DocMatch > &	matches,
		const std::string &	distanceMethod = "strongCommonPoints"
	)		const

Find the top N matches in the database for the query document.

Parameters

[in]	query	The query document, a normalized set of quantized words.
	[int]	N The number of matches to return.
[in]	distanceMethod	distance method (norm L1, etc.)
[out]	matches	IDs and scores for the top N matching database documents.
	query	The query document, a normalized set of quantized words.
	N	The number of matches to return.
[out]	matches	IDs and scores for the top N matching database documents.
[in]	distanceMethod	the method used to compute distance between histograms.

find() [2/2]

void aliceVision::voctree::Database::find	(	const std::vector< Word > &	document,
		std::size_t	N,
		std::vector< DocMatch > &	matches,
		const std::string &	distanceMethod = "strongCommonPoints"
	)		const

Find the top N matches in the database for the query document.

Parameters

[in]	document	The query document, a set of quantized words.
[in]	N	The number of matches to return.
[in]	distanceMethod	distance method (norm L1, etc.)
[out]	matches	IDs and scores for the top N matching database documents.
[in]	document	The query document, a set of quantized words.
[in]	N	The number of matches to return.
[out]	matches	IDs and scores for the top N matching database documents.
[in]	distanceMethod	the method used to compute distance between histograms.

insert()

DocId aliceVision::voctree::Database::insert	(	DocId	doc_id,
		const SparseHistogram &	document
	)

Insert a new document.

Parameters

doc_id	Unique ID of the new document to insert
document	The set of quantized words in a document/image.

Returns

An ID representing the inserted document.

sanityCheck()

void aliceVision::voctree::Database::sanityCheck	(	std::size_t	N,
		std::map< std::size_t, DocMatches > &	matches
	)		const

Perform a sanity check of the database by querying each document of the database and finding its top N matches.

Parameters

[in]	N	The number of matches to return.
[out]	matches	IDs and scores for the top N matching database documents.

size()

std::size_t aliceVision::voctree::Database::size

(

)

const

Return the size of the database in terms of number of documents.

‍**

Returns

the number of documents

Return the size of the database in terms of number of documents

Returns

the number of documents

Friends And Related Function Documentation

operator<<

std::ostream& operator<< ( std::ostream &  os, const SparseHistogram &  dv  )

friend

Todo:

Use sorted vector?

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The documentation for this class was generated from the following files:

• /home/docs/checkouts/readthedocs.org/user_builds/alicevision/checkouts/latest/src/aliceVision/voctree/Database.hpp
• /home/docs/checkouts/readthedocs.org/user_builds/alicevision/checkouts/latest/src/aliceVision/voctree/Database.cpp