How to change ImageConstPtr data?

asked 2012-02-21 22:04:33 -0500

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.

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answered 2012-02-21 22:46:11 -0500

alfa_80
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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.

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It's better to put the declaration of "current_rgb_msg" in class scope.

alfa_80 ( 2012-02-21 22:49:53 -0500 )edit

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 ( 2012-02-22 20:18:57 -0500 )edit

You cannot convert/overwrite the incoming "rgb_msg", because it is a constant value(it's read-only variable). I'm not so into openCV, I think, you can try what dlaz and Eddit suggested, that's by using straightaway cv_bridge for further processing.

alfa_80 ( 2012-02-22 20:44:25 -0500 )edit

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answered 2012-02-21 22:16:19 -0500