Package org.opencv.text

Class Text

  • public class Text
extends java.lang.Object

    • Constructor Detail

      • Text

        public Text()

    • Method Detail

      • createOCRHMMTransitionsTable

        public static Mat createOCRHMMTransitionsTable​(java.lang.String vocabulary,
                                               java.util.List<java.lang.String> lexicon)
        Utility function to create a tailored language model transitions table from a given list of words (lexicon).
        Parameters:
        vocabulary - The language vocabulary (chars when ASCII English text).
        lexicon - The list of words that are expected to be found in a particular image. 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>
        Returns:
        automatically generated

      • createERFilterNM1

        public static ERFilter createERFilterNM1​(java.lang.String filename,
                                         int thresholdDelta,
                                         float minArea,
                                         float maxArea,
                                         float minProbability,
                                         boolean nonMaxSuppression,
                                         float minProbabilityDiff)
        Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM1.xml
        Parameters:
        filename - automatically generated
        thresholdDelta - automatically generated
        minArea - automatically generated
        maxArea - automatically generated
        minProbability - automatically generated
        nonMaxSuppression - automatically generated
        minProbabilityDiff - automatically generated
        Returns:
        automatically generated

      • createERFilterNM1

        public static ERFilter createERFilterNM1​(java.lang.String filename,
                                         int thresholdDelta,
                                         float minArea,
                                         float maxArea,
                                         float minProbability,
                                         boolean nonMaxSuppression)
        Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM1.xml
        Parameters:
        filename - automatically generated
        thresholdDelta - automatically generated
        minArea - automatically generated
        maxArea - automatically generated
        minProbability - automatically generated
        nonMaxSuppression - automatically generated
        Returns:
        automatically generated

      • createERFilterNM1

        public static ERFilter createERFilterNM1​(java.lang.String filename,
                                         int thresholdDelta,
                                         float minArea,
                                         float maxArea,
                                         float minProbability)
        Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM1.xml
        Parameters:
        filename - automatically generated
        thresholdDelta - automatically generated
        minArea - automatically generated
        maxArea - automatically generated
        minProbability - automatically generated
        Returns:
        automatically generated

      • createERFilterNM1

        public static ERFilter createERFilterNM1​(java.lang.String filename,
                                         int thresholdDelta,
                                         float minArea,
                                         float maxArea)
        Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM1.xml
        Parameters:
        filename - automatically generated
        thresholdDelta - automatically generated
        minArea - automatically generated
        maxArea - automatically generated
        Returns:
        automatically generated

      • createERFilterNM1

        public static ERFilter createERFilterNM1​(java.lang.String filename,
                                         int thresholdDelta,
                                         float minArea)
        Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM1.xml
        Parameters:
        filename - automatically generated
        thresholdDelta - automatically generated
        minArea - automatically generated
        Returns:
        automatically generated

      • createERFilterNM1

        public static ERFilter createERFilterNM1​(java.lang.String filename,
                                         int thresholdDelta)
        Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM1.xml
        Parameters:
        filename - automatically generated
        thresholdDelta - automatically generated
        Returns:
        automatically generated

      • createERFilterNM1

        public static ERFilter createERFilterNM1​(java.lang.String filename)
        Reads an Extremal Region Filter for the 1st stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM1.xml
        Parameters:
        filename - automatically generated
        Returns:
        automatically generated

      • createERFilterNM2

        public static ERFilter createERFilterNM2​(java.lang.String filename,
                                         float minProbability)
        Reads an Extremal Region Filter for the 2nd stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM2.xml
        Parameters:
        filename - automatically generated
        minProbability - automatically generated
        Returns:
        automatically generated

      • createERFilterNM2

        public static ERFilter createERFilterNM2​(java.lang.String filename)
        Reads an Extremal Region Filter for the 2nd stage classifier of N&M algorithm from the provided path e.g. /path/to/cpp/trained_classifierNM2.xml
        Parameters:
        filename - automatically generated
        Returns:
        automatically generated

      • computeNMChannels

        public static void computeNMChannels​(Mat _src,
                                     java.util.List<Mat> _channels,
                                     int _mode)
        Compute the different channels to be processed independently in the N&M algorithm CITE: Neumann12.
        Parameters:
        _src - Source image. Must be RGB CV_8UC3.
        _channels - Output vector<Mat> where computed channels are stored.
        _mode - Mode of operation. Currently the only available options are: ERFILTER_NM_RGBLGrad (used by default) and ERFILTER_NM_IHSGrad. In N&M algorithm, the combination of intensity (I), hue (H), saturation (S), and gradient magnitude channels (Grad) are used in order to obtain high localization recall. This implementation also provides an alternative combination of red (R), green (G), blue (B), lightness (L), and gradient magnitude (Grad).

      • computeNMChannels

        public static void computeNMChannels​(Mat _src,
                                     java.util.List<Mat> _channels)
        Compute the different channels to be processed independently in the N&M algorithm CITE: Neumann12.
        Parameters:
        _src - Source image. Must be RGB CV_8UC3.
        _channels - Output vector<Mat> where computed channels are stored. ERFILTER_NM_RGBLGrad (used by default) and ERFILTER_NM_IHSGrad. In N&M algorithm, the combination of intensity (I), hue (H), saturation (S), and gradient magnitude channels (Grad) are used in order to obtain high localization recall. This implementation also provides an alternative combination of red (R), green (G), blue (B), lightness (L), and gradient magnitude (Grad).

      • detectRegions

        public static void detectRegions​(Mat image,
                                 ERFilter er_filter1,
                                 ERFilter er_filter2,
                                 MatOfRect groups_rects,
                                 int method,
                                 java.lang.String filename,
                                 float minProbability)
        Extracts text regions from image.
        Parameters:
        image - Source image where text blocks needs to be extracted from. Should be CV_8UC3 (color).
        er_filter1 - Extremal Region Filter for the 1st stage classifier of N&M algorithm CITE: Neumann12
        er_filter2 - Extremal Region Filter for the 2nd stage classifier of N&M algorithm CITE: Neumann12
        groups_rects - Output list of rectangle blocks with text
        method - Grouping method (see text::erGrouping_Modes). Can be one of ERGROUPING_ORIENTATION_HORIZ, ERGROUPING_ORIENTATION_ANY.
        filename - The XML or YAML file with the classifier model (e.g. samples/trained_classifier_erGrouping.xml). Only to use when grouping method is ERGROUPING_ORIENTATION_ANY.
        minProbability - The minimum probability for accepting a group. Only to use when grouping method is ERGROUPING_ORIENTATION_ANY.

      • detectRegions

        public static void detectRegions​(Mat image,
                                 ERFilter er_filter1,
                                 ERFilter er_filter2,
                                 MatOfRect groups_rects,
                                 int method,
                                 java.lang.String filename)
        Extracts text regions from image.
        Parameters:
        image - Source image where text blocks needs to be extracted from. Should be CV_8UC3 (color).
        er_filter1 - Extremal Region Filter for the 1st stage classifier of N&M algorithm CITE: Neumann12
        er_filter2 - Extremal Region Filter for the 2nd stage classifier of N&M algorithm CITE: Neumann12
        groups_rects - Output list of rectangle blocks with text
        method - Grouping method (see text::erGrouping_Modes). Can be one of ERGROUPING_ORIENTATION_HORIZ, ERGROUPING_ORIENTATION_ANY.
        filename - The XML or YAML file with the classifier model (e.g. samples/trained_classifier_erGrouping.xml). Only to use when grouping method is ERGROUPING_ORIENTATION_ANY.

      • detectRegions

        public static void detectRegions​(Mat image,
                                 ERFilter er_filter1,
                                 ERFilter er_filter2,
                                 MatOfRect groups_rects,
                                 int method)
        Extracts text regions from image.
        Parameters:
        image - Source image where text blocks needs to be extracted from. Should be CV_8UC3 (color).
        er_filter1 - Extremal Region Filter for the 1st stage classifier of N&M algorithm CITE: Neumann12
        er_filter2 - Extremal Region Filter for the 2nd stage classifier of N&M algorithm CITE: Neumann12
        groups_rects - Output list of rectangle blocks with text
        method - Grouping method (see text::erGrouping_Modes). Can be one of ERGROUPING_ORIENTATION_HORIZ, ERGROUPING_ORIENTATION_ANY.

      • detectRegions

        public static void detectRegions​(Mat image,
                                 ERFilter er_filter1,
                                 ERFilter er_filter2,
                                 MatOfRect groups_rects)
        Extracts text regions from image.
        Parameters:
        image - Source image where text blocks needs to be extracted from. Should be CV_8UC3 (color).
        er_filter1 - Extremal Region Filter for the 1st stage classifier of N&M algorithm CITE: Neumann12
        er_filter2 - Extremal Region Filter for the 2nd stage classifier of N&M algorithm CITE: Neumann12
        groups_rects - Output list of rectangle blocks with text

      • detectRegions

        public static void detectRegions​(Mat image,
                                 ERFilter er_filter1,
                                 ERFilter er_filter2,
                                 java.util.List<MatOfPoint> regions)
        Converts MSER contours (vector<Point>) to ERStat regions.
        Parameters:
        image - Source image CV_8UC1 from which the MSERs where extracted.
        regions - Output where the ERStat regions are stored. It takes as input the contours provided by the OpenCV MSER feature detector and returns as output two vectors of ERStats. This is because MSER() output contains both MSER+ and MSER- regions in a single vector<Point>, the function separates them in two different vectors (this is as if the ERStats where extracted from two different channels). An example of MSERsToERStats in use can be found in the text detection webcam_demo: <https://github.com/opencv/opencv_contrib/blob/master/modules/text/samples/webcam_demo.cpp>
        er_filter1 - automatically generated
        er_filter2 - automatically generated

      • erGrouping

        public static void erGrouping​(Mat image,
                              Mat channel,
                              java.util.List<MatOfPoint> regions,
                              MatOfRect groups_rects,
                              int method,
                              java.lang.String filename,
                              float minProbablity)
        Find groups of Extremal Regions that are organized as text blocks.
        Parameters:
        regions - Vector of ER's retrieved from the ERFilter algorithm from each channel. provided regions.
        groups_rects - The output of the algorithm are stored in this parameter as list of rectangles.
        method - Grouping method (see text::erGrouping_Modes). Can be one of ERGROUPING_ORIENTATION_HORIZ, ERGROUPING_ORIENTATION_ANY.
        filename - The XML or YAML file with the classifier model (e.g. samples/trained_classifier_erGrouping.xml). Only to use when grouping method is ERGROUPING_ORIENTATION_ANY.
        minProbablity - The minimum probability for accepting a group. Only to use when grouping method is ERGROUPING_ORIENTATION_ANY.
        image - automatically generated
        channel - automatically generated

      • erGrouping

        public static void erGrouping​(Mat image,
                              Mat channel,
                              java.util.List<MatOfPoint> regions,
                              MatOfRect groups_rects,
                              int method,
                              java.lang.String filename)
        Find groups of Extremal Regions that are organized as text blocks.
        Parameters:
        regions - Vector of ER's retrieved from the ERFilter algorithm from each channel. provided regions.
        groups_rects - The output of the algorithm are stored in this parameter as list of rectangles.
        method - Grouping method (see text::erGrouping_Modes). Can be one of ERGROUPING_ORIENTATION_HORIZ, ERGROUPING_ORIENTATION_ANY.
        filename - The XML or YAML file with the classifier model (e.g. samples/trained_classifier_erGrouping.xml). Only to use when grouping method is ERGROUPING_ORIENTATION_ANY. method is ERGROUPING_ORIENTATION_ANY.
        image - automatically generated
        channel - automatically generated

      • erGrouping

        public static void erGrouping​(Mat image,
                              Mat channel,
                              java.util.List<MatOfPoint> regions,
                              MatOfRect groups_rects,
                              int method)
        Find groups of Extremal Regions that are organized as text blocks.
        Parameters:
        regions - Vector of ER's retrieved from the ERFilter algorithm from each channel. provided regions.
        groups_rects - The output of the algorithm are stored in this parameter as list of rectangles.
        method - Grouping method (see text::erGrouping_Modes). Can be one of ERGROUPING_ORIENTATION_HORIZ, ERGROUPING_ORIENTATION_ANY. samples/trained_classifier_erGrouping.xml). Only to use when grouping method is ERGROUPING_ORIENTATION_ANY. method is ERGROUPING_ORIENTATION_ANY.
        image - automatically generated
        channel - automatically generated

      • erGrouping

        public static void erGrouping​(Mat image,
                              Mat channel,
                              java.util.List<MatOfPoint> regions,
                              MatOfRect groups_rects)
        Find groups of Extremal Regions that are organized as text blocks.
        Parameters:
        regions - Vector of ER's retrieved from the ERFilter algorithm from each channel. provided regions.
        groups_rects - The output of the algorithm are stored in this parameter as list of rectangles. ERGROUPING_ORIENTATION_ANY. samples/trained_classifier_erGrouping.xml). Only to use when grouping method is ERGROUPING_ORIENTATION_ANY. method is ERGROUPING_ORIENTATION_ANY.
        image - automatically generated
        channel - automatically generated