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Why I got '/raspicam_node/image_rect' and '/raspicam_node/camera_info' do not appear to be synchronized error message?

asked 2021-08-17 02:17:41 -0500

YJ gravatar image

updated 2021-08-17 23:13:40 -0500

Question:

I would like to try apriltag with my raspi and raspi-camera. Here is the workflow.

  1. Images would be taken from raspicam with 10Hz.
  2. Use Image_proc package to rectify the images
  3. Use Apriltag_ros to detect tags

The following link is the picture of my rqt_graph. https://drive.google.com/file/d/1XQoE...

After following the steps in the Appendix C in this post. I got the following error message and the [WARN] message continuous showing up. Also, there is no result from topic /tag_detections.

[ INFO] [1629181934.407924029]: Loaded tag config: 1, size: 0.075, frame_name: tag_1
[ INFO] [1629181934.408216996]: Loaded tag config: 2, size: 0.08, frame_name: tag_2
[INFO] [1629181934.408368766]: Loaded tag config: 3, size: 0.075, frame_name: tag_3
[INFO] [1629181934.408532411]: Loaded tag config: 4, size: 0.075, frame_name: tag_4
WARN] [1629181934.414992843]: remove_duplicates parameter not provided. Defaulting to true
[WARN][1629181944.645441278]: [image_transport] Topics '/raspicam_node/image_rect' and '/raspicam_node/camera_info' do not appear to be synchronized. In the last 10s:
Image messages received: 94
CameraInfo messages received: 99
Synchronized pairs: 1
[WARN] [1629181954.645304305]: [image_transport] Topics '/raspicam_node/image_rect' and '/raspicam_node/camera_info' do not appear to be synchronized. In the last 10s:
Image messages received: 100
CameraInfo messages received: 100
Synchronized pairs:
[WARN][1629181964.645229364]: [image_transport] Topics '/raspicam_node/image_rect' and '/raspicam_node/camera_info' do not appear to be synchronized. In the last 10s:
Image messages received: 100
CameraInfo messages received: 100
Synchronized pairs: 0
[WARN] [1629181974.645151610]: [image_transport] Topics '/raspicam_node/image_rect' and '/raspicam_node/camera_info' do not appear to be synchronized. In the last 10s:
Image messages received: 100
CameraInfo messages received: 100
Synchronized pairs: 0
[WARN] [1629181984.644698753]: [image_transport] Topics '/raspicam_node/image_rect' and '/raspicam_node/camera_info' do not appear to be synchronized. In the last 10s:
Image messages received: 100
CameraInfo messages received: 100
Synchronized pairs: 0

Is there any body could give me some hint how to fix it? Any advice would be very appreciated.

Appendix A. Environment:

Appendix B. Setup:

  1. create launch file under /opt/ros/kinetic/share/raspicam_node/launch

<launch> <arg name="enable_raw" default="false"/> <arg name="enable_imv" default="false"/> <arg name="camera_id" default="0"/> <arg name="camera_frame_id" default="raspicam"/> <arg name="camera_name" default="camerav2_320x240"/>

<node type="raspicam_node" pkg="raspicam_node" name="raspicam_node" output="screen">

<param name="camera_frame_id" value="$(arg camera_frame_id)"/>
<param name="enable_raw" value="$(arg enable_raw)"/>
<param name="enable_imv" value="$(arg enable_imv)"/>
<param name="camera_id" value="$(arg camera_id)"/>

<param name="camera_info_url" value="package://raspicam_node/camera_info/camerav2_320x240.yaml"/>
<param name="camera_name" value="$(arg camera_name)"/>
<param name="width" value="320"/>
<param name="height" value="240"/>

<param name="framerate" value="10"/>
<param name="exposure_mode" value="antishake"/>
<param name="shutter_speed" value="0"/>   </node> </launch>
  1. Revise image_proc to listen to /raspicam_node/image topic

Appendix C ...

(more)
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Comments

I'm sorry to have to do this for something so seemingly unimportant, but please don't post screenshots of terminal text in question on ROS Answers. It's all text, so there is no need. Just copy-paste the text from the terminal into your question text. Do make sure to format it properly by selecting the text and pressing ctrl+k (or clicking the Preformatted Text button (the one with 101010 on it)).

You don't need to post a new question, just edit your curent one. You can use the edit button/link for this.

After you replace the screenshot with the error message itself, we can re-open your question.

gvdhoorn gravatar image gvdhoorn  ( 2021-08-17 03:11:34 -0500 )edit

Hi Gvdhoom, I've revise the context of my questions. Please help to re-open the question. Thank you.

YJ gravatar image YJ  ( 2021-08-17 23:14:23 -0500 )edit

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answered 2022-02-11 08:10:03 -0500

Fav0z gravatar image

I have got the same problem. My environment is very similar:

  • HW: raspi 4, raspicam
  • SW: ubuntu 20.04 LTS (server), ROS Noetic
  • Same camera driver, image_proc node, apriltag implementation.

I don't know if my solution is good, but I created a node that echo the topic camera_rect and camera_info, in this node I used ApproximateTime with the Synchronizer. More info in the following ROS Guide: http://wiki.ros.org/message_filters In the callback I just published the same message (image_rect and camera_info)

Then I remap the apriltag input topics to be the syncronized ones.

This seems a very hacky way, but after some time I have to complete the task.

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Asked: 2021-08-17 02:17:41 -0500

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Last updated: Aug 17 '21