Crop and show image that i get from Haar Cascade

Question

I have trained Haar cascade and now i need to work with founded object. How i can crop it from original image and show in new window?(or show multiple window if i found 2 object on image). There is my code (opencv ver 2.4.13):

    #include <opencv2/opencv.hpp>
#include <iostream>
#include <fstream>
using namespace std;
using namespace cv;

int main(void)
{
    CascadeClassifier trafficLightCascader;
    string Cascade_name = "TrafficLight.xml";

if (!trafficLightCascader.load(Cascade_name))
{
    cout << "Can't load the face feature data" << endl;
    return -1;
}

vector<Rect> trafficLights;

Mat src = imread("6копия.png"); 
CvRect AssignRect = Rect(0, 0, src.cols, src.rows / 2);
Mat srcImage = src(AssignRect);

Mat grayImage(srcImage.rows, srcImage.cols, CV_8UC1);

cvtColor(srcImage, grayImage, CV_BGR2GRAY);
equalizeHist(grayImage, grayImage); 

trafficLightCascader.detectMultiScale(grayImage, trafficLights, 1.1, 1, 0, Size(3,3));

for (int i = 0; i < trafficLights.size(); ++i)
{
    rectangle(src, trafficLights[i], Scalar(0, 255, 0), 2, 8, 0);
}

imshow("src", src);
waitKey(0);


return 0;}

Answer 1

Your trafficLights vector is holding each rectangle's data of found objects. You just need to take left&top coordinates, width and height of each rectangle and you already have them. All you need is cropping each rectangle by creating Mat format of them and showing in different frames.

You can check here to learn more about cropping.

Here is the code which you need:

for (int i = 0; i < trafficLights.size(); ++i)
    {   
        Rect crop_found(trafficLights[i].x,trafficLights[i].y, trafficLights[i].width, trafficLights[i].height);

        Mat found(src, crop_found);

        imshow(to_string(i),found);

        rectangle(src, trafficLights[i], Scalar(0, 255, 0), 2, 8, 0);
    }