我需要使用opencvsharp识别图像中的文本 [英] I need recognize text in image using opencvsharp

问题描述

我尝试识别图片中的文字，

I trying to identify text in a image,

实际上，我想要识别图片中的文字位置，然后将其转换为文字

actualy I'm trying to identify the text positions in the image then convert it to text

我发现一些代码写在c + +和我试图将其转换为c＃
你能帮助我

i found a some code written on c++ and i try to convert it to c# can you help me please

提取文字OpenCV

std::vector<cv::Rect> detectLetters(cv::Mat img)
{       std::vector<cv::Rect> boundRect;[enter image description here][1]
    cv::Mat img_gray, img_sobel, img_threshold, element;
    cvtColor(img, img_gray, CV_BGR2GRAY);
    cv::Sobel(img_gray, img_sobel, CV_8U, 1, 0, 3, 1, 0, cv::BORDER_DEFAULT);
    cv::threshold(img_sobel, img_threshold, 0, 255, CV_THRESH_OTSU+CV_THRESH_BINARY);
    element = getStructuringElement(cv::MORPH_RECT, cv::Size(10, 15) );
    cv::morphologyEx(img_threshold, img_threshold, CV_MOP_CLOSE, element); //Does the trick
    std::vector< std::vector< cv::Point> > contours;
    cv::findContours(img_threshold, contours, 0, 1); 
    std::vector<std::vector<cv::Point> > contours_poly( contours.size() );
    for( int i = 0; i < contours.size(); i++ )
        if (contours[i].size()>80)
        { 
            cv::approxPolyDP( cv::Mat(contours[i]), contours_poly[i], 17, true );
            cv::Rect appRect( boundingRect( cv::Mat(contours_poly[i]) ));
            if (appRect.width>appRect.height) 
                boundRect.push_back(appRect);
        }
        return boundRect;
}

我尝试将其转换为c＃，但它不工作

and i try to convert it to c#, but it didn't work

private List<Rectangle> detectLetters(IntPtr img)
{
    //cvtColor(img, img_gray, CV_BGR2GRAY);
    List<Rectangle> boundRect = new List<Rectangle>();

    //cv::Mat img_gray, img_sobel, img_threshold, element;
    IntPtr 
        img_gray = IntPtr.Zero, 
        img_sobel= IntPtr.Zero, 
        img_threshold= IntPtr.Zero,
        img_tmp = IntPtr.Zero,
        element= IntPtr.Zero;

    //cvtColor(img, img_gray, CV_BGR2GRAY);
    CvInvoke.cvCvtColor(img, img_gray,COLOR_CONVERSION.CV_BGR2GRAY); //CV_BGR2GRAY);

    //cv::Sobel(img_gray, img_sobel, CV_8U, 1, 0, 3, 1, 0, cv::BORDER_DEFAULT);
    CvInvoke.cvSobel(img_gray, img_sobel, 0, 1, 1);//, 3, 1, 0, cv.BORDER_DEFAULT);

    //cv.threshold(img_sobel, img_threshold, 0, 255, CV_THRESH_OTSU + CV_THRESH_BINARY);
    CvInvoke.cvThreshold(img_sobel, img_threshold, 0, 255, THRESH.CV_THRESH_BINARY|THRESH.CV_THRESH_OTSU);

    //element = getStructuringElement(cv.MORPH_RECT, cv.Size(10, 15));
    element = CvInvoke.cvCreateStructuringElementEx(1,1,10,15,CV_ELEMENT_SHAPE.CV_SHAPE_RECT,element);// GetStructuringElement(

    //cv.morphologyEx(img_threshold, img_threshold, CV_MOP_CLOSE, element); //Does the trick
    CvInvoke.cvMorphologyEx(img_threshold,img_threshold,img_tmp,element,CV_MORPH_OP.CV_MOP_CLOSE,1);

    //List<List<cv.Point>> contours = new List<List<cv.Point>>();
    var contours = new List<IntPtr>();

    //cv.findContours(img_threshold, contours, 0, 1);
    CvInvoke.cvFindContours(img_threshold, element,ref ((IntPtr)contours[0]), 1, RETR_TYPE.CV_RETR_EXTERNAL, CHAIN_APPROX_METHOD.CV_CHAIN_APPROX_NONE,new Point(0,0));


    //std::vector<std::vector<cv::Point> > contours_poly( contours.size() );
    var contours_poly = new List<List<Point>>(contours.Count);

    //for( int i = 0; i < contours.size(); i++ )
    for (int i = 0; i < contours.Count; i++)
    {
        //if (contours[i].size()>80)
        if (contours[i].ToInt32() > 80)
        {
            //cv.approxPolyDP(Emgu.CV.Matrix<>(contours[i]), contours_poly[i], 17, true);
            CvInvoke.cvApproxPoly(contours[i], 17,contours_poly[i],APPROX_POLY_TYPE.CV_POLY_APPROX_DP, 1,1);
            //cv::Rect appRect( boundingRect( cv::Mat(contours_poly[i]) ));
            Rectangle appRect = new Rectangle(CvInvoke.cvBoundingRect(contours_poly[i],false));
            //if (appRect.width>appRect.height) 
            if (appRect.width > appRect.height)
            {
                //boundRect.push_back(appRect);
                boundRect.Add(appRect);
            }
        }
    }
    //return boundRect;
    return boundRect;
}

感谢healp :)

thanks for healp :)

推荐答案

根据您要查找的文本大小，您可能需要使用元素大小和ApproxPolyDP的变量，但这个代码非常接近

Depending on what the size of the text you're looking for, you may have to play around with the variables for element size and ApproxPolyDP but this code is pretty close to the original but in OpenCvSharp lingo.

static List<Rect> RunTextRecog(string inFile)
{
    List<Rect> boundRect = new List<Rect>();
    using (Mat img = new Mat(inFile))
    using (Mat img_gray = new Mat())
    using (Mat img_sobel = new Mat())
    using (Mat img_threshold = new Mat())
    {
        Cv2.CvtColor(img, img_gray, ColorConversionCodes.BGR2GRAY);
        Cv2.Sobel(img_gray, img_sobel, MatType.CV_8U, 1, 0, 3, 1, 0, BorderTypes.Default);
        Cv2.Threshold(img_sobel, img_threshold, 0, 255, ThresholdTypes.Otsu | ThresholdTypes.Binary);
        using (Mat element = Cv2.GetStructuringElement(MorphShapes.Rect, new Size(10, 15)))
        {
            Cv2.MorphologyEx(img_threshold, img_threshold, MorphTypes.Close, element);
            Point[][] edgesArray = img_threshold.Clone().FindContoursAsArray(RetrievalModes.External, ContourApproximationModes.ApproxNone);
            foreach (Point[] edges in edgesArray)
            {
                Point[] normalizedEdges = Cv2.ApproxPolyDP(edges, 17, true);
                Rect appRect = Cv2.BoundingRect(normalizedEdges);
                boundRect.Add(appRect);
            }
        }
    }
    return boundRect;
}

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