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+/*M//////////////////////////////////////////////////////////////////////////////////////////
+//
+// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
+//
+// By downloading, copying, installing or using the software you agree to this license.
+// If you do not agree to this license, do not download, install,
+// copy or use the software.
+//
+//
+// License Agreement
+// For Open Source Computer Vision Library
+//
+// Copyright (C) 2000-2008, Intel Corporation, all rights reserved.
+// Copyright (C) 2009, Willow Garage Inc., all rights reserved.
+// Copyright (C) 2013, OpenCV Foundation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+// * Redistribution's of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+//
+// * Redistribution's in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+//
+// * The name of the copyright holders may not be used to endorse or promote products
+// derived from this software without specific prior written permission.
+//
+// This software is provided by the copyright holders and contributors "as is" and
+// any express or implied warranties, including, but not limited to, the implied
+// warranties of merchantability and fitness for a particular purpose are disclaimed.
+// In no event shall the Intel Corporation or contributors be liable for any direct,
+// indirect, incidental, special, exemplary, or consequential damages
+// (including, but not limited to, procurement of substitute goods or services;
+// loss of use, data, or profits; or business interruption) however caused
+// and on any theory of liability, whether in contract, strict liability,
+// or tort (including negligence or otherwise) arising in any way out of
+// the use of this software, even if advised of the possibility of such damage.
+//
+//M*/
+
+#ifndef __OPENCV_TEXT_OCR_HPP__
+#define __OPENCV_TEXT_OCR_HPP__
+
+#include <vector>
+#include <string>
+
+namespace cv
+{
+namespace text
+{
+
+//! @addtogroup text_recognize
+//! @{
+
+enum
+{
+ OCR_LEVEL_WORD,
+ OCR_LEVEL_TEXTLINE
+};
+
+//base class BaseOCR declares a common API that would be used in a typical text recognition scenario
+class CV_EXPORTS_W BaseOCR
+{
+public:
+ virtual ~BaseOCR() {};
+ 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) = 0;
+ virtual void run(Mat& image, Mat& mask, 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) = 0;
+};
+
+/** @brief OCRTesseract class provides an interface with the tesseract-ocr API (v3.02.02) in C++.
+
+Notice that it is compiled only when tesseract-ocr is correctly installed.
+
+@note
+ - (C++) An example of OCRTesseract recognition combined with scene text detection can be found
+ at the end_to_end_recognition demo:
+ <https://github.com/opencv/opencv_contrib/blob/master/modules/text/samples/end_to_end_recognition.cpp>
+ - (C++) Another example of OCRTesseract recognition combined with scene text detection can be
+ found at the webcam_demo:
+ <https://github.com/opencv/opencv_contrib/blob/master/modules/text/samples/webcam_demo.cpp>
+ */
+class CV_EXPORTS_W OCRTesseract : public BaseOCR
+{
+public:
+ /** @brief Recognize text using the tesseract-ocr API.
+
+ 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.
+
+ @param image Input image CV_8UC1 or CV_8UC3
+ @param output_text Output text of the tesseract-ocr.
+ @param component_rects If provided the method will output a list of Rects for the individual
+ text elements found (e.g. words or text lines).
+ @param component_texts If provided the method will output a list of text strings for the
+ recognition of individual text elements found (e.g. words or text lines).
+ @param component_confidences If provided the method will output a list of confidence values
+ for the recognition of individual text elements found (e.g. words or text lines).
+ @param component_level OCR_LEVEL_WORD (by default), or OCR_LEVEL_TEXT_LINE.
+ */
+ 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);
+
+ virtual void run(Mat& image, Mat& mask, 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);
+
+ // aliases for scripting
+ CV_WRAP String run(InputArray image, int min_confidence, int component_level=0);
+
+ CV_WRAP String run(InputArray image, InputArray mask, int min_confidence, int component_level=0);
+
+ CV_WRAP virtual void setWhiteList(const String& char_whitelist) = 0;
+
+
+ /** @brief Creates an instance of the OCRTesseract class. Initializes Tesseract.
+
+ @param datapath the name of the parent directory of tessdata ended with "/", or NULL to use the
+ system's default directory.
+ @param language an ISO 639-3 code or NULL will default to "eng".
+ @param char_whitelist specifies the list of characters used for recognition. NULL defaults to
+ "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".
+ @param oem tesseract-ocr offers different OCR Engine Modes (OEM), by deffault
+ tesseract::OEM_DEFAULT is used. See the tesseract-ocr API documentation for other possible
+ values.
+ @param psmode tesseract-ocr offers different Page Segmentation Modes (PSM) tesseract::PSM_AUTO
+ (fully automatic layout analysis) is used. See the tesseract-ocr API documentation for other
+ possible values.
+ */
+ CV_WRAP static Ptr<OCRTesseract> create(const char* datapath=NULL, const char* language=NULL,
+ const char* char_whitelist=NULL, int oem=3, int psmode=3);
+};
+
+
+/* OCR HMM Decoder */
+
+enum decoder_mode
+{
+ OCR_DECODER_VITERBI = 0 // Other algorithms may be added
+};
+
+/** @brief 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/opencv/opencv_contrib/blob/master/modules/text/samples/webcam_demo.cpp>
+ */
+class CV_EXPORTS_W OCRHMMDecoder : public BaseOCR
+{
+public:
+
+ /** @brief Callback with the character classifier is made a class.
+
+ This way it hides the feature extractor and the classifier itself, so developers can write
+ their own OCR code.
+
+ The default character classifier and feature extractor can be loaded using the utility funtion
+ loadOCRHMMClassifierNM and KNN model provided in
+ <https://github.com/opencv/opencv_contrib/blob/master/modules/text/samples/OCRHMM_knn_model_data.xml.gz>.
+ */
+ class CV_EXPORTS_W ClassifierCallback
+ {
+ public:
+ virtual ~ClassifierCallback() { }
+ /** @brief The character classifier must return a (ranked list of) class(es) id('s)
+
+ @param image Input image CV_8UC1 or CV_8UC3 with a single letter.
+ @param out_class The classifier returns the character class categorical label, or list of
+ class labels, to which the input image corresponds.
+ @param out_confidence The classifier returns the probability of the input image
+ corresponding to each classes in out_class.
+ */
+ virtual void eval( InputArray image, std::vector<int>& out_class, std::vector<double>& out_confidence);
+ };
+
+public:
+ /** @brief Recognize text using HMM.
+
+ Takes binary 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.
+
+ @param image Input binary image CV_8UC1 with a single text line (or word).
+
+ @param output_text Output text. Most likely character sequence found by the HMM decoder.
+
+ @param component_rects If provided the method will output a list of Rects for the individual
+ text elements found (e.g. words).
+
+ @param component_texts If provided the method will output a list of text strings for the
+ recognition of individual text elements found (e.g. words).
+
+ @param component_confidences If provided the method will output a list of confidence values
+ for the recognition of individual text elements found (e.g. words).
+
+ @param component_level Only OCR_LEVEL_WORD is supported.
+ */
+ 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);
+
+ /** @brief Recognize text using HMM.
+
+ Takes an image and a mask (where each connected component corresponds to a segmented character)
+ 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.
+
+ @param image Input image CV_8UC1 or CV_8UC3 with a single text line (or word).
+ @param mask Input binary image CV_8UC1 same size as input image. Each connected component in mask corresponds to a segmented character in the input image.
+
+ @param output_text Output text. Most likely character sequence found by the HMM decoder.
+
+ @param component_rects If provided the method will output a list of Rects for the individual
+ text elements found (e.g. words).
+
+ @param component_texts If provided the method will output a list of text strings for the
+ recognition of individual text elements found (e.g. words).
+
+ @param component_confidences If provided the method will output a list of confidence values
+ for the recognition of individual text elements found (e.g. words).
+
+ @param component_level Only OCR_LEVEL_WORD is supported.
+ */
+ virtual void run(Mat& image, Mat& mask, 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);
+
+ // aliases for scripting
+ CV_WRAP String run(InputArray image, int min_confidence, int component_level=0);
+
+ CV_WRAP String run(InputArray image, InputArray mask, int min_confidence, int component_level=0);
+
+ /** @brief Creates an instance of the OCRHMMDecoder class. Initializes HMMDecoder.
+
+ @param classifier The character classifier with built in feature extractor.
+
+ @param vocabulary The language vocabulary (chars when ascii english text). vocabulary.size()
+ must be equal to the number of classes of the classifier.
+
+ @param transition_probabilities_table Table with transition probabilities between character
+ pairs. cols == rows == vocabulary.size().
+
+ @param emission_probabilities_table Table with observation emission probabilities. cols ==
+ rows == vocabulary.size().
+
+ @param mode HMM Decoding algorithm. Only OCR_DECODER_VITERBI is available for the moment
+ (<http://en.wikipedia.org/wiki/Viterbi_algorithm>).
+ */
+ static Ptr<OCRHMMDecoder> create(const Ptr<OCRHMMDecoder::ClassifierCallback> classifier,// The character classifier with built in feature extractor
+ const std::string& vocabulary, // The language vocabulary (chars when ascii english text)
+ // size() must be equal to the number of classes
+ InputArray transition_probabilities_table, // Table with transition probabilities between character pairs
+ // cols == rows == vocabulari.size()
+ InputArray emission_probabilities_table, // Table with observation emission probabilities
+ // cols == rows == vocabulari.size()
+ decoder_mode mode = OCR_DECODER_VITERBI); // HMM Decoding algorithm (only Viterbi for the moment)
+
+ CV_WRAP static Ptr<OCRHMMDecoder> create(const Ptr<OCRHMMDecoder::ClassifierCallback> classifier,// The character classifier with built in feature extractor
+ const String& vocabulary, // The language vocabulary (chars when ascii english text)
+ // size() must be equal to the number of classes
+ InputArray transition_probabilities_table, // Table with transition probabilities between character pairs
+ // cols == rows == vocabulari.size()
+ InputArray emission_probabilities_table, // Table with observation emission probabilities
+ // cols == rows == vocabulari.size()
+ int mode = OCR_DECODER_VITERBI); // HMM Decoding algorithm (only Viterbi for the moment)
+
+protected:
+
+ Ptr<OCRHMMDecoder::ClassifierCallback> classifier;
+ std::string vocabulary;
+ Mat transition_p;
+ Mat emission_p;
+ decoder_mode mode;
+};
+
+/** @brief Allow to implicitly load the default character classifier when creating an OCRHMMDecoder object.
+
+@param filename The XML or YAML file with the classifier model (e.g. OCRHMM_knn_model_data.xml)
+
+The KNN default classifier is based in the scene text recognition method proposed by Lukás Neumann &
+Jiri Matas in [Neumann11b]. Basically, the region (contour) in the input image is normalized to a
+fixed size, while retaining the centroid and aspect ratio, in order to extract a feature vector
+based on gradient orientations along the chain-code of its perimeter. Then, the region is classified
+using a KNN model trained with synthetic data of rendered characters with different standard font
+types.
+ */
+
+CV_EXPORTS_W Ptr<OCRHMMDecoder::ClassifierCallback> loadOCRHMMClassifierNM(const String& filename);
+
+/** @brief Allow to implicitly load the default character classifier when creating an OCRHMMDecoder object.
+
+@param filename The XML or YAML file with the classifier model (e.g. OCRBeamSearch_CNN_model_data.xml.gz)
+
+The CNN default classifier is based in the scene text recognition method proposed by Adam Coates &
+Andrew NG in [Coates11a]. The character classifier consists in a Single Layer Convolutional Neural Network and
+a linear classifier. It is applied to the input image in a sliding window fashion, providing a set of recognitions
+at each window location.
+ */
+CV_EXPORTS_W Ptr<OCRHMMDecoder::ClassifierCallback> loadOCRHMMClassifierCNN(const String& filename);
+
+//! @}
+
+/** @brief Utility function to create a tailored language model transitions table from a given list of words (lexicon).
+ *
+ * @param vocabulary The language vocabulary (chars when ascii english text).
+ *
+ * @param lexicon The list of words that are expected to be found in a particular image.
+ *
+ * @param transition_probabilities_table Output table with transition probabilities between character pairs. cols == rows == vocabulary.size().
+ *
+ * The function calculate frequency statistics of character pairs from the given lexicon and fills the output transition_probabilities_table with them. The transition_probabilities_table can be used as input in the OCRHMMDecoder::create() and OCRBeamSearchDecoder::create() methods.
+ * @note
+ * - (C++) An alternative would be to load the default generic language transition table provided in the text module samples folder (created from ispell 42869 english words list) :
+ * <https://github.com/opencv/opencv_contrib/blob/master/modules/text/samples/OCRHMM_transitions_table.xml>
+ **/
+CV_EXPORTS void createOCRHMMTransitionsTable(std::string& vocabulary, std::vector<std::string>& lexicon, OutputArray transition_probabilities_table);
+
+CV_EXPORTS_W Mat createOCRHMMTransitionsTable(const String& vocabulary, std::vector<cv::String>& lexicon);
+
+
+/* OCR BeamSearch Decoder */
+
+/** @brief OCRBeamSearchDecoder class provides an interface for OCR using Beam Search algorithm.
+
+@note
+ - (C++) An example on using OCRBeamSearchDecoder recognition combined with scene text detection can
+ be found at the demo sample:
+ <https://github.com/opencv/opencv_contrib/blob/master/modules/text/samples/word_recognition.cpp>
+ */
+class CV_EXPORTS_W OCRBeamSearchDecoder : public BaseOCR
+{
+public:
+
+ /** @brief Callback with the character classifier is made a class.
+
+ This way it hides the feature extractor and the classifier itself, so developers can write
+ their own OCR code.
+
+ The default character classifier and feature extractor can be loaded using the utility funtion
+ loadOCRBeamSearchClassifierCNN with all its parameters provided in
+ <https://github.com/opencv/opencv_contrib/blob/master/modules/text/samples/OCRBeamSearch_CNN_model_data.xml.gz>.
+ */
+ class CV_EXPORTS_W ClassifierCallback
+ {
+ public:
+ virtual ~ClassifierCallback() { }
+ /** @brief The character classifier must return a (ranked list of) class(es) id('s)
+
+ @param image Input image CV_8UC1 or CV_8UC3 with a single letter.
+ @param recognition_probabilities For each of the N characters found the classifier returns a list with
+ class probabilities for each class.
+ @param oversegmentation The classifier returns a list of N+1 character locations' x-coordinates,
+ including 0 as start-sequence location.
+ */
+ virtual void eval( InputArray image, std::vector< std::vector<double> >& recognition_probabilities, std::vector<int>& oversegmentation );
+
+ int getWindowSize() {return 0;}
+ int getStepSize() {return 0;}
+ };
+
+public:
+ /** @brief Recognize text using Beam Search.
+
+ 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.
+
+ @param image Input binary image CV_8UC1 with a single text line (or word).
+
+ @param output_text Output text. Most likely character sequence found by the HMM decoder.
+
+ @param component_rects If provided the method will output a list of Rects for the individual
+ text elements found (e.g. words).
+
+ @param component_texts If provided the method will output a list of text strings for the
+ recognition of individual text elements found (e.g. words).
+
+ @param component_confidences If provided the method will output a list of confidence values
+ for the recognition of individual text elements found (e.g. words).
+
+ @param component_level Only OCR_LEVEL_WORD is supported.
+ */
+ 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);
+
+ virtual void run(Mat& image, Mat& mask, 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);
+
+ // aliases for scripting
+ CV_WRAP String run(InputArray image, int min_confidence, int component_level=0);
+
+ CV_WRAP String run(InputArray image, InputArray mask, int min_confidence, int component_level=0);
+
+ /** @brief Creates an instance of the OCRBeamSearchDecoder class. Initializes HMMDecoder.
+
+ @param classifier The character classifier with built in feature extractor.
+
+ @param vocabulary The language vocabulary (chars when ascii english text). vocabulary.size()
+ must be equal to the number of classes of the classifier.
+
+ @param transition_probabilities_table Table with transition probabilities between character
+ pairs. cols == rows == vocabulary.size().
+
+ @param emission_probabilities_table Table with observation emission probabilities. cols ==
+ rows == vocabulary.size().
+
+ @param mode HMM Decoding algorithm. Only OCR_DECODER_VITERBI is available for the moment
+ (<http://en.wikipedia.org/wiki/Viterbi_algorithm>).
+
+ @param beam_size Size of the beam in Beam Search algorithm.
+ */
+ static Ptr<OCRBeamSearchDecoder> create(const Ptr<OCRBeamSearchDecoder::ClassifierCallback> classifier,// The character classifier with built in feature extractor
+ const std::string& vocabulary, // The language vocabulary (chars when ascii english text)
+ // size() must be equal to the number of classes
+ InputArray transition_probabilities_table, // Table with transition probabilities between character pairs
+ // cols == rows == vocabulari.size()
+ InputArray emission_probabilities_table, // Table with observation emission probabilities
+ // cols == rows == vocabulari.size()
+ decoder_mode mode = OCR_DECODER_VITERBI, // HMM Decoding algorithm (only Viterbi for the moment)
+ int beam_size = 500); // Size of the beam in Beam Search algorithm
+
+ CV_WRAP static Ptr<OCRBeamSearchDecoder> create(const Ptr<OCRBeamSearchDecoder::ClassifierCallback> classifier, // The character classifier with built in feature extractor
+ const String& vocabulary, // The language vocabulary (chars when ascii english text)
+ // size() must be equal to the number of classes
+ InputArray transition_probabilities_table, // Table with transition probabilities between character pairs
+ // cols == rows == vocabulari.size()
+ InputArray emission_probabilities_table, // Table with observation emission probabilities
+ // cols == rows == vocabulari.size()
+ int mode = OCR_DECODER_VITERBI, // HMM Decoding algorithm (only Viterbi for the moment)
+ int beam_size = 500); // Size of the beam in Beam Search algorithm
+
+protected:
+
+ Ptr<OCRBeamSearchDecoder::ClassifierCallback> classifier;
+ std::string vocabulary;
+ Mat transition_p;
+ Mat emission_p;
+ decoder_mode mode;
+ int beam_size;
+};
+
+/** @brief Allow to implicitly load the default character classifier when creating an OCRBeamSearchDecoder object.
+
+@param filename The XML or YAML file with the classifier model (e.g. OCRBeamSearch_CNN_model_data.xml.gz)
+
+The CNN default classifier is based in the scene text recognition method proposed by Adam Coates &
+Andrew NG in [Coates11a]. The character classifier consists in a Single Layer Convolutional Neural Network and
+a linear classifier. It is applied to the input image in a sliding window fashion, providing a set of recognitions
+at each window location.
+ */
+
+CV_EXPORTS_W Ptr<OCRBeamSearchDecoder::ClassifierCallback> loadOCRBeamSearchClassifierCNN(const String& filename);
+
+//! @}
+
+}
+}
+#endif // _OPENCV_TEXT_OCR_HPP_