Subscribe to Kinect depth intensity value (not mm)

asked 2019-08-29 14:44:45 -0600

incendiary gravatar image

updated 2019-08-29 14:49:18 -0600


I would like to get Kinect's depth value for each pixel as intensity (0-255) as put them in an array. Right now I am subscribing to /camera/depth/image_raw. When I rostopich echo I get that, but when I subscribe to it with a callback, I get values in mm. My callback is:

void MyClass::rgbdSubscriberCallback(const sensor_msgs::ImageConstPtr& msg2) {
  cv_bridge::CvImagePtr cv_ptr; Eigen::MatrixXd A(480, 640);
    cv_ptr=cv_bridge::toCvCopy(msg2,sensor_msgs::image_encodings::TYPE_16UC1); //16UC1, sensor_msgs::image_encodings::BRG8
      cv::imshow("Depth Image",cv_ptr->image); cv::waitKey(30); // display image
    for(int i=0; i<(cv_ptr->image).rows; i++) {for(int j=0; j<(cv_ptr->image).cols; j++) {
      A(i,j)=(cv_ptr-><short int>(cv::Point(i,j)));///255.0;
    std::cout<<"Maximum Kinect Depth is: "<<A.array().maxCoeff()<<std::endl; // >30000
  catch (cv_bridge::Exception& e) {ROS_ERROR("cv_bridge exception: Could not convert from '%s' to '16UC1'.", e.what());} 

I think I am serializing the data to make it displayable in cv::Mat, but I do not want to use this mat's pixel values, I want the (0-255) intensities from the topic I mentioned. I am subscribing with the openni driver and I've seen people complain their values are (0-255), but this is exactly what I want.

Thank you.

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seems like an encoding issue, just check the encoding value of your message and use same encoding in your node

Choco93 gravatar image Choco93  ( 2019-08-30 05:44:20 -0600 )edit