cv::text::OCRHMMDecoder Class Reference

OCRHMMDecoder class provides an interface for OCR using Hidden Markov Models. More...

#include "ocr.hpp"

Inheritance diagram for cv::text::OCRHMMDecoder:

Classes
class	ClassifierCallback
	Callback with the character classifier is made a class. More...

Public Member Functions
virtual void	run (Mat &image, std::string &output_text, std::vector< Rect > *component_rects=NULL, std::vector< std::string > *component_texts=NULL, std::vector< float > *component_confidences=NULL, int component_level=0)
	Recognize text using HMM. More...
Public Member Functions inherited from cv::text::BaseOCR
virtual	~BaseOCR ()

Static Public Member Functions
static Ptr< OCRHMMDecoder >	create (const Ptr< OCRHMMDecoder::ClassifierCallback > classifier, const std::string &vocabulary, InputArray transition_probabilities_table, InputArray emission_probabilities_table, decoder_mode mode=OCR_DECODER_VITERBI)
	Creates an instance of the OCRHMMDecoder class. Initializes HMMDecoder. More...

Protected Attributes
Ptr < OCRHMMDecoder::ClassifierCallback >	classifier
Mat	emission_p
decoder_mode	mode
Mat	transition_p
std::string	vocabulary

Detailed Description

OCRHMMDecoder class provides an interface for OCR using Hidden Markov Models.

Note

• (C++) An example on using OCRHMMDecoder recognition combined with scene text detection can be found at the webcam_demo sample: https://github.com/Itseez/opencv_contrib/blob/master/modules/text/samples/webcam_demo.cpp

Member Function Documentation

static Ptr<OCRHMMDecoder> cv::text::OCRHMMDecoder::create ( const Ptr< OCRHMMDecoder::ClassifierCallback >  classifier, const std::string &  vocabulary, InputArray  transition_probabilities_table, InputArray  emission_probabilities_table, decoder_mode  mode = OCR_DECODER_VITERBI  )

static

Creates an instance of the OCRHMMDecoder class. Initializes HMMDecoder.

Parameters

classifier	The character classifier with built in feature extractor.
vocabulary	The language vocabulary (chars when ascii english text). vocabulary.size() must be equal to the number of classes of the classifier.
transition_probabilities_table	Table with transition probabilities between character pairs. cols == rows == vocabulary.size().
emission_probabilities_table	Table with observation emission probabilities. cols == rows == vocabulary.size().
mode	HMM Decoding algorithm. Only OCR_DECODER_VITERBI is available for the moment (http://en.wikipedia.org/wiki/Viterbi_algorithm).

virtual void cv::text::OCRHMMDecoder::run ( Mat &  image, std::string &  output_text, std::vector< Rect > *  component_rects = NULL, std::vector< std::string > *  component_texts = NULL, std::vector< float > *  component_confidences = NULL, int  component_level = 0  )

virtual

Recognize text using HMM.

Takes image on input and returns recognized text in the output_text parameter. Optionally provides also the Rects for individual text elements found (e.g. words), and the list of those text elements with their confidence values.

Parameters

image	Input image CV_8UC1 with a single text line (or word).
output_text	Output text. Most likely character sequence found by the HMM decoder.
component_rects	If provided the method will output a list of Rects for the individual text elements found (e.g. words).
component_texts	If provided the method will output a list of text strings for the recognition of individual text elements found (e.g. words).
component_confidences	If provided the method will output a list of confidence values for the recognition of individual text elements found (e.g. words).
component_level	Only OCR_LEVEL_WORD is supported.

Implements cv::text::BaseOCR.

Member Data Documentation

Ptr<OCRHMMDecoder::ClassifierCallback> cv::text::OCRHMMDecoder::classifier

protected

Mat cv::text::OCRHMMDecoder::emission_p

protected

decoder_mode cv::text::OCRHMMDecoder::mode

protected

Mat cv::text::OCRHMMDecoder::transition_p

protected

std::string cv::text::OCRHMMDecoder::vocabulary

protected

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

• /Users/build/test/opencv_contrib/modules/text/include/opencv2/text/ocr.hpp