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All modules / text

text_BaseOCRclass

base class BaseOCR declares a common API that would be used in a typical text recognition scenario

text_classifier_typeclass

OCR classifier type

text_computeNMChannelsfunction

Compute the different channels to be processed independently in the N&M algorithm [Neumann12].

text_createERFilterNM1function

Create an Extremal Region Filter for the 1st stage classifier of N&M algorithm [Neumann12].

text_createERFilterNM11function

Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm

text_createERFilterNM2function

Create an Extremal Region Filter for the 2nd stage classifier of N&M algorithm [Neumann12].

text_createERFilterNM21function

Reads an Extremal Region Filter for the 2nd stage classifier of N&M algorithm

text_createOCRHMMTransitionsTablefunction

Utility function to create a tailored language model transitions table from a given list of words (lexicon).

text_decoder_modeclass

OCR HMM Decoder

text_detectRegionsfunction

Utility funtion for scripting

text_detectRegions1function

Extracts text regions from image.

text_detectTextSWTfunction

Applies the Stroke Width Transform operator followed by filtering of connected components of similar Stroke Widths to return letter candidates. It also chain them by proximity and

text_ERFilterclass

Base class for 1st and 2nd stages of Neumann and Matas scene text detection algorithm [Neumann12]. :

text_ERFilter_Callbackclass

Callback with the classifier is made a class.

text_erGroupingfunction

Find groups of Extremal Regions that are organized as text blocks.

text_erGrouping_Modesclass

text::erGrouping operation modes

text_loadClassifierNM1function

Allow to implicitly load the default classifier when creating an ERFilter object.

text_loadClassifierNM2function

Allow to implicitly load the default classifier when creating an ERFilter object.

text_loadOCRBeamSearchClassifierCNNfunction

Allow to implicitly load the default character classifier when creating an OCRBeamSearchDecoder object.

text_loadOCRHMMClassifierfunction

Allow to implicitly load the default character classifier when creating an OCRHMMDecoder object.

text_loadOCRHMMClassifierCNNfunction

Allow to implicitly load the default character classifier when creating an OCRHMMDecoder object.

text_loadOCRHMMClassifierNMfunction

Allow to implicitly load the default character classifier when creating an OCRHMMDecoder object.

text_ocr_engine_modeclass

Tesseract.OcrEngineMode Enumeration

text_OCRBeamSearchDecoderclass

OCR BeamSearch Decoder

text_OCRBeamSearchDecoder_ClassifierCallbackclass

Callback with the character classifier is made a class.

text_OCRBeamSearchDecoder_createfunction

Creates an instance of the OCRBeamSearchDecoder class. Initializes HMMDecoder.

text_OCRHMMDecoderclass

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

text_OCRHMMDecoder_ClassifierCallbackclass

Callback with the character classifier is made a class.

text_OCRHMMDecoder_createfunction

Creates an instance of the OCRHMMDecoder class. Initializes HMMDecoder.

text_OCRHMMDecoder_create1function

HMM Decoding algorithm (only Viterbi for the moment)

text_OCRTesseractclass

OCRTesseract class provides an interface with the tesseract-ocr API (v3.02.02) in C++.

text_OCRTesseract_createfunction

Creates an instance of the OCRTesseract class. Initializes Tesseract.

text_page_seg_modeclass

Tesseract.PageSegMode Enumeration

text_TextDetectorclass

An abstract class providing interface for text detection algorithms

text_TextDetectorCNNclass

TextDetectorCNN class provides the functionallity of text bounding box detection.

text_TextDetectorCNN_createfunction

Creates an instance of the TextDetectorCNN class using the provided parameters.

Constants

Use the named constant from cv. In particular, OpenCV 5 matrix type codes differ from OpenCV 4.

text_ERFILTER_NM_RGBLGrad: computeNMChannels operation modes
text_ERFILTER_NM_RGBLGRAD: computeNMChannels operation modes
text_ERFILTER_NM_IHSGrad: text erfilter nm ihsgrad constant (1), defined by OpenCV for cv::text.
text_ERFILTER_NM_IHSGRAD: text erfilter nm ihsgrad constant (1), defined by OpenCV for cv::text.
text_ERGROUPING_ORIENTATION_HORIZ: Exhaustive Search algorithm proposed in [Neumann11] for grouping horizontally aligned text. The algorithm models a verification function for all the possible ER sequences. The verification fuction for ER pairs consists in a set of threshold-based pairwise rules which compare measurements of two regions (height ratio, centroid angle, and region distance). The verification function for ER triplets creates a word text line estimate using Least Median-Squares fitting for a given triplet and then verifies that the estimate is valid (based on thresholds created during training). Verification functions for sequences larger than 3 are approximated by verifying that the text line parameters of all (sub)sequences of length 3 are consistent.
text_ERGROUPING_ORIENTATION_ANY: Text grouping method proposed in [Gomez13] [Gomez14] for grouping arbitrary oriented text. Regions are agglomerated by Single Linkage Clustering in a weighted feature space that combines proximity (x,y coordinates) and similarity measures (color, size, gradient magnitude, stroke width, etc.). SLC provides a dendrogram where each node represents a text group hypothesis. Then the algorithm finds the branches corresponding to text groups by traversing this dendrogram with a stopping rule that combines the output of a rotation invariant text group classifier and a probabilistic measure for hierarchical clustering validity assessment.

Note: This mode is not supported due NFA code removal ( https://github.com/opencv/opencv_contrib/issues/2235 )
text_OCR_LEVEL_WORD: text ocr level word constant (0), defined by OpenCV for cv::text.
text_OCR_LEVEL_TEXTLINE: text ocr level textline constant (1), defined by OpenCV for cv::text.
text_PSM_OSD_ONLY: text psm osd only constant (0), defined by OpenCV for cv::text.
text_PSM_AUTO_OSD: text psm auto osd constant (1), defined by OpenCV for cv::text.
text_PSM_AUTO_ONLY: text psm auto only constant (2), defined by OpenCV for cv::text.
text_PSM_AUTO: text psm auto constant (3), defined by OpenCV for cv::text.
text_PSM_SINGLE_COLUMN: text psm single column constant (4), defined by OpenCV for cv::text.
text_PSM_SINGLE_BLOCK_VERT_TEXT: text psm single block vert text constant (5), defined by OpenCV for cv::text.
text_PSM_SINGLE_BLOCK: text psm single block constant (6), defined by OpenCV for cv::text.
text_PSM_SINGLE_LINE: text psm single line constant (7), defined by OpenCV for cv::text.
text_PSM_SINGLE_WORD: text psm single word constant (8), defined by OpenCV for cv::text.
text_PSM_CIRCLE_WORD: text psm circle word constant (9), defined by OpenCV for cv::text.
text_PSM_SINGLE_CHAR: text psm single char constant (10), defined by OpenCV for cv::text.
text_OEM_TESSERACT_ONLY: text oem tesseract only constant (0), defined by OpenCV for cv::text.
text_OEM_CUBE_ONLY: text oem cube only constant (1), defined by OpenCV for cv::text.
text_OEM_TESSERACT_CUBE_COMBINED: text oem tesseract cube combined constant (2), defined by OpenCV for cv::text.
text_OEM_DEFAULT: text oem default constant (3), defined by OpenCV for cv::text.
text_OCR_DECODER_VITERBI: Other algorithms may be added
text_OCR_KNN_CLASSIFIER: text ocr knn classifier constant (0), defined by OpenCV for cv::text.
text_OCR_CNN_CLASSIFIER: text ocr cnn classifier constant (1), defined by OpenCV for cv::text.