Search multiple colours simultaneously with opencv and c++ - opencv

Question

I am trying to make the code below search multiple colours at the same time e.g. red, yellow and orange. I have added masks to the code but a cant get them to apply properly what am i doing wrong I am not sure if the line to add the masks to the frame is in the right place or not.
#include "stdafx.h"
#include <cv.h>
#include <highgui.h>
using namespace std;
using namespace cv::gpu;
IplImage* GetThresholdedImage(IplImage* imgHSV){
IplImage* imgThresh=cvCreateImage(cvGetSize(imgHSV),IPL_DEPTH_8U, 1);
cvInRangeS(imgHSV, cvScalar(170,160,60), cvScalar(180,255,256), imgThresh);
return imgThresh;
}
int main(){
//Char Firetype = type;
CvCapture* capture = cvCaptureFromCAM(1);
if(!capture){
printf("Capture failure\n");
return -1;
}
IplImage* frame=0;
cvNamedWindow("Video");
cvNamedWindow("Fire");
cvNamedWindow("Info");
//iterate through each frame of the video
while(true){
frame = cvQueryFrame(capture);
if(!frame) break;
frame=cvCloneImage(frame);
cvSmooth(frame, frame, CV_GAUSSIAN,3,3); //smooth the original image using Gaussian kernel
cv::Mat imgMat(frame);
cv::Mat mask1;
cv::inRange(imgMat, cv::Scalar(20, 100, 100), cv::Scalar(30, 255, 255), mask1);
cv::Mat mask2;
cv::inRange(imgMat, cv::Scalar(170,160,60), cv::Scalar(180,255,256), mask2);
cv::Mat mask3;
cv::inRange(imgMat, cv::Scalar(70,160,60), cv::Scalar(90,255,256), mask3);
// combine them
cv::Mat mask_combined = mask1 | mask2 | mask3;
// now since our frame from the camera is bgr, we have to convert our mask to 3 channels:
cv::Mat mask_rgb;
cv::cvtColor( mask_combined, mask_rgb, CV_GRAY2BGR );
IplImage framemask = imgMat & mask_rgb;
IplImage* imgHSV = cvCreateImage(cvGetSize(framemask), IPL_DEPTH_8U, 3);
cvCvtColor(frame, imgHSV, CV_BGR2HSV); //Change the color format from BGR to HSV
//This function threshold the HSV image and create a binary image
// function below to get b&w image
IplImage* imgThresh = GetThresholdedImage(imgHSV);
cvSmooth(imgThresh, imgThresh, CV_GAUSSIAN,3,3); //smooth the binary image using Gaussian kernel
cvShowImage("Fire", imgThresh);
cvShowImage("Video", frame);
// cvNamedWindow("Info", Firetype);
cvReleaseImage(&imgHSV);
cvReleaseImage(&imgThresh);
cvReleaseImage(&frame);
//Wait 50mS
int c = cvWaitKey(10);
//If 'ESC' is pressed, break the loop
if((char)c==27 ) break;
}
cvDestroyAllWindows() ;
cvReleaseCapture(&capture);
return 0;
}

Answer 1

tl:dr;
use bitwise-or to combine binary masks,
bitwise_and to apply them
cv::Mat mask1;
cv::inRange( hsv, cv::Scalar(20, 100, 100), cv::Scalar(30, 255, 255), mask1);
cv::Mat mask2;
cv::inRange( hsv, cv::Scalar(170,160,60), cv::Scalar(180,255,256), mask2);
cv::Mat mask3;
cv::inRange( hsv, cv::Scalar(70,160,60), cv::Scalar(90,255,256), mask3);
// combine them
cv::Mat mask_combined = mask1 | mask2 | mask3;
// now since our frame from the camera is bgr, we have to convert our mask to 3 channels:
cv::Mat mask_rgb;
cv::cvtColor( mask_combined, mask_rgb, CV_GRAY2BGR );
// finally, apply the mask to our image
frame = frame & mask_rgb;