9-1-3字元切割

9-1-3字元切割

#include <iostream>
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <vector>
#include <algorithm>

bool verifyOCSizes(cv::Mat r){
    //Char sizes 45x77
    float aspect = 45.0f / 77.0f;
    float charAspect = (float)r.cols / (float)r.rows;
    float error = 0.35;
    float minHeight = 15;
    float maxHeight = 28;
    //We have a different aspect ratio for number 1, and it can be ~0.2
    float minAspect = 0.2;
    float maxAspect = aspect + aspect*error;
    //area of pixels
    float area = countNonZero(r);
    //bb area
    float bbArea = r.cols*r.rows;
    //% of pixel in area
    float percPixels = area / bbArea;

    std::cout << "Aspect: " << aspect << " [" << minAspect << "," << maxAspect << "] " << "Area " << percPixels << " Char aspect " << charAspect << " Height char " << r.rows << "\n";

    if (percPixels < 0.8 && charAspect > minAspect && charAspect < maxAspect && r.rows >= minHeight && r.rows < maxHeight)
       return true;
    else
       return false;

}


cv::Mat preprocessChar(cv::Mat in){
    //Remap image
    int h = in.rows;
    int w = in.cols;
    cv::Mat transformMat = cv::Mat::eye(2, 3, CV_32F);
    int m = std::max(w, h);
    transformMat.at(0, 2) = m / 2 - w / 2;
    transformMat.at(1, 2) = m / 2 - h / 2;

    cv::Mat warpImage(m, m, in.type());
    warpAffine(in, warpImage, transformMat, warpImage.size(), cv::INTER_LINEAR, cv::BORDER_CONSTANT, cv::Scalar(0));

    cv::Mat out;
    cv::resize(warpImage, out, cv::Size(20, 20));

    return out;
}


int main(int argc, char** argv)
{
    cv::Mat carPlate = cv::imread("carPlate.bmp", 0);

    if (!carPlate.data)
    {
       std::cout << "無法讀取圖片" << std::endl;
       return -1;
    }

    cv::Mat imgBinary;
    cv::threshold(carPlate, imgBinary, 60, 255, CV_THRESH_BINARY_INV);

    cv::imshow("Threshold plate", imgBinary);
    cv::waitKey(0);

    cv::Mat imgContour;
    imgBinary.copyTo(imgContour);

    //Find contours of possibles characters
    std::vector< std::vector< cv::Point> > contours;
    findContours(imgContour,
    contours, // a vector of contours
    CV_RETR_EXTERNAL, // retrieve the external contours
    CV_CHAIN_APPROX_NONE); // all pixels of each contours

    // Draw blue contours on a white image
    cv::Mat result;
    imgBinary.copyTo(result);
    cvtColor(result, result, CV_GRAY2RGB);
    cv::drawContours(result, contours,
    -1, // draw all contours
    cv::Scalar(255, 0, 0), // in blue
    1); // with a thickness of 1

    //Start to iterate to each contour founded
    std::vector >::iterator itc = contours.begin();

    std::vector output;

    //Remove patch that are no inside limits of aspect ratio and area.
    int i = 0;
    while (itc != contours.end())
    {
       //Create bounding rect of object
       cv::Rect mr = cv::boundingRect(cv::Mat(*itc));
       rectangle(result, mr, cv::Scalar(0, 255, 0));
       //Crop image
       cv::Mat auxRoi(imgBinary, mr);
       if (verifyOCSizes(auxRoi))
       {
          auxRoi = preprocessChar(auxRoi); //20x20
          cv::Mat segChar = auxRoi.clone();
          output.push_back(segChar);
          rectangle(result, mr, cv::Scalar(0, 125, 255));

          cv::Mat largeChar;
          cv::resize(segChar, largeChar, cv::Size(200,200));

          cv::imshow("char", largeChar);
          cv::waitKey(0);

          std::string filename = "file";
          int num = i;
          std::stringstream numS;
          numS << i;
          filename = filename + numS.str() + ".bmp";

          cv::imwrite(filename, segChar);
          i++;
       }
       ++itc;
    }
    std::cout << "Num chars: " << output.size() << "\n";

    cv::imshow("SEgmented Chars", result);

    return 0;
}