OpenCV - 乐透号码识别

Question

我正在尝试创建一个可以自动识别彩票号码的程序。

我已经识别出平局的时刻，将球分开，现在我的问题是我无法识别球上的数字。

这是原图：

这是我找到轮廓后的照片：

现在对于每个轮廓，我尝试确定它是否是一个数字以及它是什么数字。这就是我的应用失败的地方。

*重要的是，球可以有多个角度/灯光可以不同，这都会影响图片的质量。

这是我的 prog 找到的轮廓 img 的示例：

这是我识别号码的代码：

private void identifyNumber(Mat inFile) {
    System.out.println("\nRunning identifyNumber");
    System.out.println("-------------------------");

    int match_method = Imgproc.TM_SQDIFF;
    Mat img = inFile;
    Mat bestImage = new Mat(), rotImg;
    int bestDegree = 0, bestNumber = 0;
    double lowerstFornumber, lowest = 1E30;
    String templateNumber;

    for (int k=0 ; k<=9; k++) {
        lowerstFornumber = 1E30;
        for(int i=-90; i<=90; i=i+5){
            templateNumber = "C:\\pics\\drawProcessing\\numbers\\" + k + ".png"; 
            Mat templ = Highgui.imread(templateNumber);

            rotImg = rotateImage(img, i);
            int result_cols = rotImg.cols() - templ.cols() + 1;
            int result_rows = rotImg.rows() - templ.rows() + 1;
            Mat result = new Mat(result_rows, result_cols, CvType.CV_32FC1);

            Imgproc.matchTemplate(rotImg, templ, result, match_method);

            MinMaxLocResult mmr = Core.minMaxLoc(result);

            Point matchLoc;
            if (match_method == Imgproc.TM_SQDIFF || match_method == Imgproc.TM_SQDIFF_NORMED) {
                matchLoc = mmr.minLoc;
            } else {
                matchLoc = mmr.maxLoc;
            }

            double minValue = mmr.minVal;

//          System.out.println(i+",maxVal:" +maxValue);

            if(lowerstFornumber > minValue){
                lowerstFornumber = minValue;
            }

            if(lowest > minValue){
                lowest = minValue;
                bestImage = rotImg;
                bestDegree = i;
                bestNumber = arr[k];
            }
        }
        System.out.println("lowerstFornumber " + arr[k] + "  :" + lowerstFornumber);
    }

    System.out.println("bestDegree:" + bestDegree);
    System.out.println("bestNumber:" + bestNumber);
    System.out.println("_lowest:" + lowest);
    Highgui.imwrite("C:\\pics\\drawProcessing\\out-best.jpg", bestImage);    
}

有时它会找到号码，有时却找不到。 有可能吗？（我需要 100% 的准确率） 我做错了吗？

Answer 1

如果您尝试为您的盒子使用仿射不变描述符会怎样？您甚至可以从更简单的描述符开始，例如 sift 或 surf，针对每个区域计算并匹配到数据库。它应该很快，因为看起来规模不会改变。 Sift 和 surf 可能会给你一些结果，但为了更稳定，你可以使用 ASIFT。

Answer 2

不是在java中，但它描述了这个想法：

#include <iostream>
#include <vector>
#include <string>
#include <fstream>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;


//----------------------------------------------------------------------
// 
//----------------------------------------------------------------------
void DetectContour(Mat& img, Mat& res)
{
    vector<vector<Point> > contours;
    vector<Vec4i> hierarchy;
    Mat edges=img.clone();
    //Canny(img, edges, 50, 190, 3);
    img.copyTo(edges);
    findContours(edges,contours, hierarchy, cv::RETR_EXTERNAL, cv::CHAIN_APPROX_NONE, Point());
    if(contours.size()>0)
    {
        for( int i = 0; i < contours.size(); i++ )
        {
            vector<Point> approx;
            approxPolyDP(Mat(contours[i]), approx, arcLength(Mat(contours[i]), true)*0.02, true);
            double area = contourArea(Mat(approx));

            if(area>200)
                drawContours( res, contours, i, Scalar(255,0,0), CV_FILLED, 8);
        }
    }
}
//----------------------------------------------------------------------
// 
//----------------------------------------------------------------------
int main(int argc, char **argv)
{
    cv::namedWindow("result");
    Mat img=imread("ball.png");

    // Prepare mask
    Mat mask=Mat::zeros(img.size(),CV_8UC1);
    Mat img_gray;
    cv::cvtColor(img,img_gray,cv::COLOR_BGR2GRAY);
    Mat res=Mat(img.size(),CV_8UC1);
    res=255;

    vector<Vec3f> circles;

    /// Apply the Hough Transform to find the circles

    HoughCircles( img_gray, circles, cv::HOUGH_GRADIENT, 1, img_gray.rows/8, 140, 70, 0,0 );

    /// Draw the circles detected
    for( size_t i = 0; i < circles.size(); i++ )
    {
        Point center(cvRound(circles[i][0]), cvRound(circles[i][1]));
        int radius = cvRound(circles[i][2]);
        // circle outline
        circle( mask, center, radius, Scalar(255,255,255), -1, 8, 0 );
    }
    img.copyTo(res,mask);

    cv::cvtColor(res,res,cv::COLOR_BGR2GRAY);

    threshold(res,res,80,255,cv::THRESH_BINARY_INV);
    mask=0;
    DetectContour(res,mask);

    mask.copyTo(res);

    int element_size=10;
    Mat element = getStructuringElement( cv::MORPH_ELLIPSE,Size( 2*element_size + 1, 2*element_size+1 ),Point( element_size, element_size ) );

    int element_size2=5;
    Mat element2 = getStructuringElement( cv::MORPH_ELLIPSE,Size( 2*element_size + 1, 2*element_size+1 ),Point( element_size, element_size ) );

    cv::dilate(res,res,element2);
    cv::erode(res,res,element);

    vector<vector<Point> > contours;
    vector<Vec4i> hierarchy;

    findContours(res,contours, hierarchy, cv::RETR_EXTERNAL, cv::CHAIN_APPROX_NONE, Point());
    for (int i=0;i<contours.size();++i)
    {
        RotatedRect box = minAreaRect(contours[i]);
        Point2f center, vtx[4];
        box.points(vtx);

        float w=100;
        float h=100;
        // Create a column vector with the coordinates of each point (on the field plane)
        cv::Mat xField;
        xField.create(4, 1, CV_32FC2);
        xField.at<Point2f>(0) = ( vtx[0] );
        xField.at<Point2f>(1) = ( vtx[1] );
        xField.at<Point2f>(2) = ( vtx[2] );
        xField.at<Point2f>(3) = ( vtx[3] );

        // same thing for xImage but with the pixel coordinates instead of the field coordinates, same order as in xField
        cv::Mat xImage;
        xImage.create(4, 1, CV_32FC2);
        xImage.at<Point2f>(0) = ( cv::Point2f(0, 0) );
        xImage.at<Point2f>(1) = ( cv::Point2f(w, 0) );
        xImage.at<Point2f>(2) = ( cv::Point2f(w, h) );
        xImage.at<Point2f>(3) = ( cv::Point2f(0, h) );

        // Compute the homography matrix
        cv::Mat H = cv::findHomography(xField,xImage );
        xField.release();
        xImage.release();

        Mat warped;
        warpPerspective(img,warped,H,Size(w,h));
        H.release();
        char win_name[255];
        sprintf(win_name,"number_image %d",i);
        namedWindow(win_name);
        imshow(win_name,warped);
//      cv::waitKey(0);

        for(int j = 0; j < 4; j++ )
        {
            line(img, vtx[j], vtx[(j+1)%4], Scalar(0, 255, 0), 1, LINE_AA); 
        }

    }




    imshow("result",img);
    cv::waitKey(0);

    cv::destroyAllWindows();
}