Ros2 confidence map/depth question

Nicola · May 7, 2024, 7:11pm

Hi,
I am running ros2 wrapper around zed sdk 4.1 and my depth map and confidence colors (shades of grey) are the inverse when displayed in rviz compared with the zed depth explorer.
I am curious if this is normal. I saw in the documentation for the confidence map on this page: Adding Depth Perception in ROS 2 - Stereolabs that “The lighter a pixel, the more reliable its corresponding depth value is.” which seems opposite of what the screenshot next to this phrase depicts, looking for some clarification. Thank you!

Myzhar · May 8, 2024, 7:58am

Hi @Nicola
the difference is that in ZED Depth Viewer the displayed confidence map comes from the command retrieveImage with parameter sl::VIEW::CONFIDENCE, hence it is an image to be displayed.

RVIZ instead displays the “real” Confidence Map, with normalized values that comes from retrieveMeasure:

github.com

stereolabs/zed-ros2-wrapper/blob/master/zed_components/src/zed_camera/src/zed_camera_component.cpp#L6966-L6973


      
          if (mConfMapSubnumber > 0) {
            DEBUG_STREAM_VD("Retrieving Confidence");
            retrieved |= sl::ERROR_CODE::SUCCESS ==
              mZed->retrieveMeasure(
              mMatConf, sl::MEASURE::CONFIDENCE,
              sl::MEM::CPU, mMatResol);
            mSdkGrabTS = mMatConf.timestamp;
          }