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I am using this code
topic is: /camera/depth/image
type: /sensor_msgs/Image
According to the code, (msg->data[0]) is providing the value of Top-Left Corner.
I wanted to ask:
In the code the message is already converted to a cv::Mat ( cv_ptr->image ). Use this Matrix if you want to do some processing of the data.
E.g. you can use
float dist_val = cv_ptr->image.at<float>( 10, 10 );
to get the value at 10, 10. (There are much faster methods if you not just want to access one pixel, though).
See, http://docs.opencv.org for infos on how to handle your data with OpenCV.
That very much depends on what you actually want to do. Probably some of the core and improc tutorials. If you want to do object detection: "Creating Bounding boxes and circles for contours"(particularly cv::findContours() usage). Threshold works also for dist imgs. Likely you need some normalizing.
Thanks, @Wolf, this solution worked for me. I have used /camera/depth/image_raw as an input rostopic.
My answer with complete code (c++): https://answers.ros.org/question/1417...
Extra:
To get image dimension: std::cout <<
"Image dimension (Row x Col): " <<
cv_ptr->image.rows << " x " <<
cv_ptr->image.cols << endl;
To get
image global max and min depth
values:
double min = 0.0;
double max = 0.0;
cv::minMaxLoc(cv_ptr->image, &min, &max, 0, 0);
std::cout << "Min value: " << min << " " << "Max value: " << max << endl;
hi but this is giving me always dist_val=0 !! why is that so ??
Asked: 2014-02-01 00:54:14 -0600
Seen: 8,056 times
Last updated: Apr 18 '17
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Your reference code helped, thanks