Merging two ofxCvGrayscaleImage into one

extend
#1

Hi,

I have two ofxCvGrayscaleImages (640 x 480) captured from two webcams. I would like to merged them in a new one with the same height (480) but with double width (1280) in order to pass it to contourFinder. I created a third one and tried to add them and translate them both, but it didn’t work. Do I have to convert the ofxCvGrayscaleImage to ofPixels and them back again to ofxCvGrayscaleImage ir order no merge these two images or is there a better way?

Thanks!

#2

So far a partial solution. I used a FBO to join the two video streams into a ofImage, but i cannot send this to ofxopencv, i need a solution to convert the ofimage into a ofxgrayscale. But i haven’t found yet.

  
  
#include "testApp.h"  
  
//--------------------------------------------------------------  
void testApp::setup(){  
  
    ofBackground(255,255,255);  
  
  
    vidGrabber.setDeviceID(0);  
    // vidGrabber.setDesiredFrameRate(30);  
    vidGrabber.initGrabber(640,480);  
  
    // vidGrabber.setVerbose(true);  
    vidGrabber2.setDeviceID(1);  
    // vidGrabber.setDesiredFrameRate(30);  
    vidGrabber2.initGrabber(640,480);  
  
    fbo.allocate(1280,480,GL_RGBA);  
  
    pix.allocate(1280, 480, 4);  
  
}  
  
//--------------------------------------------------------------  
void testApp::update(){  
  
    vidGrabber.update();  
    vidGrabber2.update();  
  
}  
  
//--------------------------------------------------------------  
void testApp::draw(){  
  
    fbo.begin();  
    vidGrabber.draw(0, 0, 640, 480);  
    vidGrabber2.draw(640, 0, 640, 480);  
    fbo.end();  
  
    tex = fbo.getTextureReference();  
    tex.readToPixels(pix);  
  
    pix.crop(0, 100, 1260, 100);  
    img.setFromPixels(pix);  
  
    // fbo.draw(0, 0, 1280, 480);  
    img.draw(0,500);  
  
}
#3

Problem solved:

  
  
  
void testApp::update(){  
  
    bool newFrame1 = false;  
    bool newFrame2 = false;  
  
    vidGrabber1.grabFrame();  
    vidGrabber2.grabFrame();  
  
    newFrame1 = vidGrabber1.isFrameNew();  
    newFrame2 = vidGrabber2.isFrameNew();  
  
    if(newFrame1 || newFrame2){  
  
        // put the 2 streams on a FBO  
        fbo.begin();  
        vidGrabber2.draw(0, 0, 320, 240);  
        vidGrabber1.draw(320,0,320,240);  
        fbo.end();  
  
        ofTexture tex = fbo.getTextureReference(); // from FBO to Texture  
        tex.readToPixels(pix); // from texture to pixels  
        colorImg.setFromPixels(pix); // from pixels to ofxCvImage  
        colorImg.flagImageChanged(); // update the iplm image  
  
        grayImage = colorImg;  
  
        grayDiff.absDiff(grayBg, grayImage);  
		grayDiff.threshold(threshold);  
  
        if (learnBackground == true){  
            if(newFrame1 && newFrame2){  
                grayBg = grayImage;		// the = sign copys the pixels from grayImage into grayBg (operator overloading)  
                learnBackground = false;  
            }  
		}  
  
        contourFinder.findContours(grayDiff, 20, (640*480)/3, 1, false);  
    }  
  
}
1 Like
#4

Hey irminsul!
I need to do exactly that! Im trying your code but im having some problems. Can you tell me what did you have on draw() in your final solution?
Thanks!