coin date ocr

edit

Hello, I am trying to setup an automated way to get the date from coins. I am keeping it simple and decided to first try it on pennies since the dates are in the same location in relation to its circle. I am using tesseract for the OCR of the date. I am having difficulty processing the date from the penny so that tesseract will correctly translate it.

My question is, does anyone have a good idea what I can do to the image from a penny's date field so that tesseract will translate correctly. I am trying morphologies but can't get the right setting so that it works.

Here is my code(needs alot of cleanup but does the job)

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "tesseract/baseapi.h"
#include "iostream"

using namespace cv;
using namespace std;

static void help()
{
    cout << "\nThis program demonstrates circle finding with the Hough transform.\n"
            "Usage:\n"
            "./houghcircles <image_name>, Default is pic1.png\n" << endl;
}

/**
 * Rotate an image
 */
void rotate(cv::Mat& src, double angle, cv::Mat& dst)
{
    int len = std::max(src.cols, src.rows);
    cv::Point2f pt(len/2., len/2.);
    cv::Mat r = cv::getRotationMatrix2D(pt, angle, 1.0);

    cv::warpAffine(src, dst, r, cv::Size(len, len));
}

int main(int argc, char** argv)
{
    const char* filename = argc >= 2 ? argv[1] : "board.jpg";


    int centerx,centery, radius;

    //Mat img = imread(filename, 0);
    Mat img = imread(filename,0);

    Mat org;
    img.copyTo(org);

    Mat date_img;

    if(img.empty())
    {
        help();
        cout << "can not open " << filename << endl;
        return -1;
    }

    Mat cimg;
    medianBlur(img, img, 5);
    cvtColor(img, cimg, COLOR_GRAY2BGR);

    vector<Vec3f> circles;
    HoughCircles(img, circles, HOUGH_GRADIENT, 1, 300,
                 100, 30, 400, 2000 // change the last two parameters
                                // (min_radius & max_radius) to detect larger circles
                 );
    for( size_t i = 0; i < circles.size(); i++ )
    {
        Vec3i c = circles[i];
        circle( cimg, Point(c[0], c[1]), c[2], Scalar(0,255,255), 3, LINE_AA);
        circle( cimg, Point(c[0], c[1]), 2, Scalar(0,255,0), 3, LINE_AA);

    centerx = c[0]; 
    centery = c[1];
    radius = c[2];  

    cv::Mat mask = cv::Mat::zeros( img.rows, img.cols, CV_8UC1 );
    circle( mask, Point(c[0], c[1]), c[2], Scalar(255,255,255), -1, 8, 0 ); //-1 means filled
    org.copyTo( cimg, mask ); // copy values of img to dst if mask is > 0.

    break;

    }

    //cv::Mat roi( cimg, cv::Rect( centerx-radius, centery-radius, radius*2, radius*2 ) );
    cout << "DIAMETER: " <<  radius  << " CENTERX: " << centerx << " CENTERY: " << centery << endl;

    cv::Rect myROI(centerx-radius,  centery-radius, radius*2,radius*2);
    cimg = cimg(myROI);

 //  rotate(cimg, 90, cimg);




 //   rectangle(cimg, Point(cimg.rows/1.45, cimg.cols/1.6),Point(cimg.rows/1.1,cimg.cols/1.35), Scalar(0,255,255), 3, 8, 0 );

    //get date
    date_img = cimg(Rect( Point(cimg.rows/1.45, cimg.cols/1.6),Point(cimg.rows/1.1,cimg.cols/1.35) ) ) ;
    date_img.convertTo(date_img, -1, 1.8, 1);


    Mat element = getStructuringElement(MORPH_ELLIPSE, Size(15,15), Point(-1,-1) );
    erode(date_img,date_img, element);
    //dilate ...