hans's profile - activity

Hello everybody... i am trying to convert an c++ to an java code. ㅠ..ㅠ

The difficulty is I do not know c ++ syntax. help :D

web - http://opencv-code.com/tutorials/auto... source - https://github.com/bsdnoobz/opencv-co...

/**
 * Automatic perspective correction for quadrilateral objects. See the tutorial at
 * http://opencv-code.com/tutorials/automatic-perspective-correction-for-quadrilateral-objects/
 */
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <iostream>

cv::Point2f center(0,0);

cv::Point2f computeIntersect(cv::Vec4i a, 
                             cv::Vec4i b)
{
    int x1 = a[0], y1 = a[1], x2 = a[2], y2 = a[3], x3 = b[0], y3 = b[1], x4 = b[2], y4 = b[3];
    float denom;

    if (float d = ((float)(x1 - x2) * (y3 - y4)) - ((y1 - y2) * (x3 - x4)))
    {
        cv::Point2f pt;
        pt.x = ((x1 * y2 - y1 * x2) * (x3 - x4) - (x1 - x2) * (x3 * y4 - y3 * x4)) / d;
        pt.y = ((x1 * y2 - y1 * x2) * (y3 - y4) - (y1 - y2) * (x3 * y4 - y3 * x4)) / d;
        return pt;
    }
    else
        return cv::Point2f(-1, -1);
}

void sortCorners(std::vector<cv::Point2f>& corners, 
                 cv::Point2f center)
{
    std::vector<cv::Point2f> top, bot;

    for (int i = 0; i < corners.size(); i++)
    {
        if (corners[i].y < center.y)
            top.push_back(corners[i]);
        else
            bot.push_back(corners[i]);
    }
    corners.clear();

    if (top.size() == 2 && bot.size() == 2){
        cv::Point2f tl = top[0].x > top[1].x ? top[1] : top[0];
        cv::Point2f tr = top[0].x > top[1].x ? top[0] : top[1];
        cv::Point2f bl = bot[0].x > bot[1].x ? bot[1] : bot[0];
        cv::Point2f br = bot[0].x > bot[1].x ? bot[0] : bot[1];


        corners.push_back(tl);
        corners.push_back(tr);
        corners.push_back(br);
        corners.push_back(bl);
    }
}

int main()
{
    cv::Mat src = cv::imread("image.jpg");
    if (src.empty())
        return -1;

    cv::Mat bw;
    cv::cvtColor(src, bw, CV_BGR2GRAY);
    cv::blur(bw, bw, cv::Size(3, 3));
    cv::Canny(bw, bw, 100, 100, 3);

    std::vector<cv::Vec4i> lines;
    cv::HoughLinesP(bw, lines, 1, CV_PI/180, 70, 30, 10);

    // Expand the lines
    for (int i = 0; i < lines.size(); i++)
    {
        cv::Vec4i v = lines[i];
        lines[i][0] = 0;
        lines[i][1] = ((float)v[1] - v[3]) / (v[0] - v[2]) * -v[0] + v[1]; 
        lines[i][2] = src.cols; 
        lines[i][3] = ((float)v[1] - v[3]) / (v[0] - v[2]) * (src.cols - v[2]) + v[3];
    }

    std::vector<cv::Point2f> corners;
    for (int i = 0; i < lines.size(); i++)
    {
        for (int j = i+1; j < lines.size(); j++)
        {
            cv::Point2f pt = computeIntersect(lines[i], lines[j]);
            if (pt.x >= 0 && pt.y >= 0)
                corners.push_back(pt);
        }
    }

    std::vector<cv::Point2f> approx;
    cv::approxPolyDP(cv::Mat(corners), approx, cv::arcLength(cv::Mat(corners), true) * 0.02, true);

    if (approx.size() != 4)
    {
        std::cout << "The object is not quadrilateral!" << std::endl;
        return -1;
    }

    // Get mass center
    for (int i = 0; i < corners.size(); i++)
        center += corners[i];
    center *= (1. / corners.size());

    sortCorners(corners, center);
    if (corners.size() == 0){
        std::cout << "The corners were not sorted correctly!" << std::endl;
        return -1;
    }
    cv::Mat dst = src.clone();

    // Draw ...