OpenCV change colors in real time camera feed

Question

I am using openCV 2.4.9. I open camera using OpenCV run camera in a new window. I want to change colors of camera feed whith a key press. For example, when I click '1' camera feed change to gray scale, '2' -> black and white, '3' -> HSV, and when I press 'ESC' return(0). This what I've came up so far:

#include <iostream>
#include <conio.h>
using namespace std;

#include<opencv\cv.h>
#include<opencv\highgui.h>
#include "opencv2\core\core.hpp"
#include "opencv2\imgproc\imgproc.hpp"


void main(){

  CvCapture *capture = cvCaptureFromCAM(CV_CAP_ANY);
  IplImage *frame = 0, *image = 0;
  int key = 0, last = 0;

  cvNamedWindow("WebCamera", CV_WINDOW_AUTOSIZE);

  while(key != 27)  {

          frame = cvQueryFrame(capture);
          image = cvCloneImage(frame);

        // i try to use swich and case for this but i can't get it work
        // when using cvtColor need to use Mat image but when use cvShowImage need IplImage 
        //  switch(last)
        //  {
        //      case '1': 
        //           cvtColor(image,HSVimage,CV_BGR2HSV);
        //      case '2': 
        //           cvtColor(image,HSVimage,CV_BGR2GRAY);
        //      case '3': 
        //           . 
        //           .
        //      default: break;
        //  }


          cvShowImage("WebCamera", image);
          cvReleaseImage(&image);
          key = cvWaitKey(1);
          if (key != -1) last = key;
  }
  cvDestroyWindow("WebCamera");
  cvReleaseCapture(&capture);

  exit(0);
}

I want change colors again and again in same window or (if it is not possible) open and close windows for each color filter. Thank You. Sorry for bad English

Answer 1

It should work with the code below. Got it from this OpenCV tutorial and from the OpenCV documentation .

#include "opencv2/opencv.hpp"
#include <iostream>

using namespace cv;
using namespace std;

int main()
{
    int key = 0, last = 0;
    VideoCapture cap(0); // open the default camera
    if(!cap.isOpened()) // check if we camera is opened
    { 
        cout << "Cannot open selected camera" << endl;
        return -1;   
    } 
    namedWindow("Capture",1);
    Mat convertedImage;

    for(;;) //Loop until user hit "esc"
    {
        Mat frame;
        cap >> frame; // get a new frame from camera            

        switch(last)
        {
           case '1':
           { 
               cvtColor(frame,convertedImage,CV_BGR2GRAY);
               break;
           }
          case '2': //Binarization to generate Black/White image
          {
               Mat img_gray;
               cvtColor(frame,img_gray,CV_BGR2GRAY); //First convert to gray
               //Binarization. Use your parameters here or try adaptiveThreshold
               threshold(img_gray, convertedIamge, 0, 255, CV_THRESH_BINARY | CV_THRESH_OTSU); 
          }
          case '3': 
          {  
              cvtColor(frame,convertedImage,CV_BGR2HSV);
              break;
          }
          default: //use to prevent ecxeption at program start or use case '0' to show original image
          {
                  convertedImage = frame;
          }
        }

        imshow("Capture", convertedImage); //show converted image

        key = waitKey(1);
        if (key != -1)             
            last = key;  

        if(key == 27)
          break;            

        // the camera will be deinitialized automatically in VideoCapture destructor
    }
    return 0;
}

Answer 2

I not checked this(compileted).. But I think it can help you.

#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
using namespace cv;
using namespace std;

int main() {
VideoCapture stream1(0);

if (!stream1.isOpened()) { cout << "cannot open camera"; }

while (true) {
Mat cameraFrame;
stream1.read(cameraFrame);
switch(last)
{
case '1': 
cvtColor(image,HSVimage,CV_BGR2HSV);
break;
case '2': 
cvtColor(image,HSVimage,CV_BGR2GRAY);
break;
case '3': 
...}
imshow("cam", cameraFrame);
key = cvWaitKey(1);
if (key != -1) last = key;
}
return 0;
}