title: Convert 4 channel image to 3 Channel image
body: <p>I am using OpenCV 2.4.6. I am trying to convert a 4channel RGB IplImage to 4channel HSV image. Below is my code. Which is giving error "OpenCV Error: Assertion failed in unknown function". I think cvCvtColor supports 3channel images. Is there any way of converting 4channel RGB to HSV or 4channel RGB to 3channel RGB?</p>
  
  <pre><code> IplImage*  mCVImageColor = cvCreateImageHeader(cvSize(640,480), IPL_DEPTH_8U, 4);
   /*Doing something*/
   IplImage* imgHSV = cvCreateImage(cvGetSize(mCVImageColor), IPL_DEPTH_8U, 4);
   cvCvtColor(mCVImageColor, imgHSV, CV_BGR2HSV); //This line throws exception
  </code></pre>