Hi all!

I am trying to background subtraction using MOG subtractor with kinect depth data.

Code is below.

 class ImageConverter
{
cv_bridge::CvImagePtr cv_ptr;
ros::NodeHandle nh_;
image_transport::ImageTransport it_;
image_transport::Subscriber image_sub_;

//for back_sub
//global variables
Mat frame; //current frame
Mat fgMaskMOG; //fg mask generated by MOG method
Mat fgMaskMOG2; //fg mask fg mask generated by MOG2 method
Ptr<BackgroundSubtractor> pMOG; //MOG Background subtractor
Ptr<BackgroundSubtractor> pMOG2; //MOG2 Background subtractor


public:
ImageConverter(): it_(nh_)
  {
  //image_sub_ = it_.subscribe("/camera/rgb/image_color", 1, &ImageConverter::imageCb, this);
  image_sub_ = it_.subscribe("camera/depth/image", 1, &ImageConverter::imageCb, this);

        pMOG= new BackgroundSubtractorMOG(); //MOG approach
        pMOG2 = new BackgroundSubtractorMOG2(); //MOG2 approach

 }

 ~ImageConverter()
  {
   cv::destroyWindow(WINDOW);
   destroyAllWindows();
  }


 void imageCb(const sensor_msgs::ImageConstPtr& msg)
  {
cv_ptr = cv_bridge::toCvCopy(msg, sensor_msgs::image_encodings::TYPE_32FC1);
    processVideo();
   cv::waitKey(3);

 }


    void processVideo()
    {
        imshow("Image", cv_ptr->image);
        pMOG->operator()(cv_ptr->image, fgMaskMOG);
       imshow("Image2", fgMaskMOG);

    }

 };

 int main(int argc, char** argv)
  {
     ros::init(argc, argv, "subtract_node");
    ImageConverter ic;
     ros::spin();
    return 0;
 }

Error is :

terminate called after throwing an instance of 'cv::Exception'  what():/build/buildd/opencv-.4.8+dfsg1/modules/video/src/bgfg_gaussmix.cpp:117 :
 error: (-215) CV_MAT_DEPTH(frameType) == CV_8U in function initialize

Thanks!