ros2 runtime_error ai_generated true

cv_bridge.CvBridgeError: [ImageConvert] Unsupported conversion from bgr8 to mono8

ID: ros2/cv-bridge-conversion-error

Also available as: JSON · Markdown
88%Fix Rate
90%Confidence
3Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
2 active — — —

Root Cause

cv_bridge cannot convert between the requested image encodings. Source and target encoding mismatch.

generic

Workarounds

  1. 92% success Use the correct desired_encoding in imgmsg_to_cv2 
    cv_image = bridge.imgmsg_to_cv2(msg, desired_encoding='bgr8')
  2. 88% success Convert after receiving using OpenCV cvtColor 
    cv_image = bridge.imgmsg_to_cv2(msg, 'passthrough'); cv_image = cv2.cvtColor(cv_image, cv2.COLOR_BGR2GRAY)
  3. 85% success Check camera topic encoding with ros2 topic echo --field encoding 
    ros2 topic echo /camera/image_raw --field encoding --once

Dead Ends

Common approaches that don't work:

  1. Force encoding to passthrough and manually convert 72% fail

    Passthrough skips validation; OpenCV may segfault on unexpected data layouts

  2. Change the camera driver encoding to match your code 80% fail

    Other subscribers depend on the original encoding; breaks the whole image pipeline