what is the best for object tracking??

edit

I have one urdf model of a car. It gets one camera in front of it. its grabbing the picture and publishing on a topic. I have write a callBack function where it will receive the image data. By the pixel by pixel data it will convert it to a opencv image, and will display on a window. Now my next step is to use the image data to track one target object. which will be the best way to do. I am really stuck in here.

 flag = 0;
 ROS_INFO("in image node function");
 int h = *(&img->height);
 int w = *(&img->width);
 cv::WImageBuffer3_b image(h,w);
 int step = image.WidthStep();
 step = 3; 
 for(int i=(h-1);i>=0;i--)
   {
    for(int j=(w-1);j>=0;j--)
     { 
       *(image(i,j)) = *(&img->data[count]);
       count++;
       *(image(i,j)+1) = *(&img->data[count]);
       count++;
       *(image(i,j)+2) = *(&img->data[count]);
        count++;
      }
    }
 //ROS_INFO("data = [%d]",*(&img->data[0]));
 cvStartWindowThread();
cvShowImage("view",image.Ipl());

the above is my imagecall back function. I have all the pixel data. please help me. Thank you in advance