Hi all!
Please explain me how could I change raw data in ImageConstPtr& object? I have a function like:
void filterImage (const sensor_msgs::ImageConstPtr& rgb_msg)
{
// something like rgb_msg->data[100] = 0;
}
So, I should change image data, and then pass rgb_msg to other functions.
I see deprecated functions get_data_vec and set_data_vec in Image.h file, but looks like I could not use them cause I have const modifier on object, and set_data_vec is non-const function.
Thank you.
You might want to try something like below:
void filterImage (const sensor_msgs::ImageConstPtr& rgb_msg)
{
sensor_msgs::Image current_rgb_msg;
current_rgb_msg = *rgb_msg;
}
You can further manipulate the value from current_rgb_msg variable.
As I understood, "current_rgb_msg" is a copy of object, referenced by "rgb_msg". Ok, that means, that all changes would be actually for "current_rgb_msg" object. Could you please explain, how to convert "current_rgb_msg" to "const sensor_msgs::ImageConstPtr&" after all changes? Thanks.
Konstantin Cherenkov (Feb 23)editYou should probably copy the data to another sensor_msgs::Image and then modify it, as you are supposed to read only from const data.
If you're doing any real image processing, you should use cv_bridge to convert it to an OpenCV type first.
Here is the example how to copy your ImageConstPtr& object to opencv obj:
void filterImage (const sensor_msgs::ImageConstPtr& rgb_msg)
{
cv::namedWindow(WINDOW);
cv_bridge::CvImagePtr cv_ptr;
try {
cv_ptr = cv_bridge::toCvCopy(rgb_msg, enc::BGR8);
}
catch (cv_bridge::Exception& e)
{
ROS_ERROR("cv_bridge exception: %s", e.what()); return; }
cv::imshow(WINDOW, cv_ptr->image);
cv::waitKey(10);
}
Asked: Feb 22
Seen: 88 times
Last updated: Feb 22
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