使用opencv c ++裁剪三角形 [英] Crop Triangle with opencv c++

问题描述

用户，

我想在图像上裁剪该三角形并使用 opencv c++ 在另一个窗口中显示它.我知道所有三个坐标.谁能帮我?我在网上没有找到任何关于三角形裁剪"的答案.谢谢！

I want to crop that Triangle on the image and show it in another window with opencv c++. I know all three Coordinates. Can anyone help me? I did not find any answer on the Internet about "triangle cropping". Thanks!

这里的问题是我不能使用 ROI 来裁剪三角形.我只需要复制没有任何背景或其他东西的三角形.是否可以通过知道三角形 [p1(302,179), p2(329,178), p3(315,205)] 的坐标来创建我自己的 ROI?

The Problem here is that i cannot use ROI for cropping the Triangle. I have to copy just the triangle without any background or something around. Is it possible to create my own ROI by knowing the Coordinates of the triangle [p1(302,179), p2(329,178), p3(315,205)]?

推荐答案

你可以使用掩码来实现，如下面的代码所示

you can do it by using mask as shown with the code below

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>

using namespace cv;
using namespace std;

int main( int, char** argv )
{
    Mat src = imread( argv[1] );
    Mat gray;

    cvtColor(src, gray, COLOR_BGR2GRAY );
    gray = gray < 127;

    vector<vector<Point> > contours;

    findContours(gray, contours,
                 RETR_EXTERNAL,
                 CHAIN_APPROX_SIMPLE);

    for( size_t i = 0; i< contours.size(); i++ )
    {
        Rect rect = boundingRect(contours[i]);
        Mat mask = gray(rect);
        Mat srcROI = src(rect);
        srcROI.setTo(Scalar(0,0,255),mask);
        imshow("srcROI",srcROI);
        waitKey();
    }

    imshow( "result", src );

    waitKey(0);
    return(0);
}

根据问题的变化，我建议使用下面的测试代码

according the change on the question i suggest the test code below

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"

using namespace cv;
using namespace std;

int main( int, char** argv )
{
    Mat src = imread("lena.jpg");
    vector<Point> points;
    points.push_back( Point(200,200));
    points.push_back( Point(370,370));
    points.push_back( Point(220,410));

    Mat mask = Mat::zeros( src.size(), CV_8UC1 );
    fillConvexPoly( mask, points, Scalar( 255 ));

    Rect rect = boundingRect( points );
    Mat roi = src( rect ).clone();
    mask = mask( rect ).clone();

    rect.x = rect.x - 180;
    rect.y = rect.y - 180;

    Mat srcROI = src( rect );
    roi.copyTo( srcROI, mask );

    imshow( "result", src );

    waitKey(0);
    return(0);
}

这篇关于使用opencv c ++裁剪三角形的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！