Deimos

ROS package for i3D Robotics' Deimos stereo camera, derived from the e-consystems See3CAM_Stereo (Tara) camera driver. This driver is in turn based on the uvc_camera package. We have made significant improvements to the driver which make it a lot more usable in ROS.

Status

Installation

For an easy setup, a rosinstall file is provided in 'install' folder of this repo which can be used to get this package and it's dependent ros packages in your workspace. In your ROS workspace use the following command:

wstool init src https://raw.githubusercontent.com/i3drobotics/i3dr_deimos-ros/main/install/i3dr_deimos_https.rosinstall

If you already have a wstool workspace setup then use the following command instead:

wstool merge -t src https://raw.githubusercontent.com/i3drobotics/i3dr_deimos-ros/main/install/i3dr_deimos_https.rosinstall
wstool update -t src

If you do not use wstool, you can download the packages using the following command:

cd PATH_TO_ROS_WS/src
git clone https://github.com/i3drobotics/i3dr_deimos-ros.git
git clone https://github.com/i3drobotics/i3dr_stereo_camera-ros.git

To install package dependences use rodep:

rosdep install --from-paths src --ignore-src -r -y

Build using catkin (tested with catkin_make and catkin_build):

catkin_make
or
catkin build

Plug in your Deimos camera to your machine and use the following launch file to test:

roslaunch i3dr_deimos deimos.launch

To check everything is working add the paramter 'rviz':

roslaunch i3dr_deimos deimos.launch rviz:=true

This package has been tested informally on Ubuntu 16.04, but should run on most distros. It has also been tested on the Jetson TX1 and TX2.

Sample Bag

The camera system can be tested when the camera is not connected by using one of our sample bags. These can be downloaded using the 'download.sh' script in the 'bag' folder:

./download.sh

Scene001: Random objects (wooden blocks, book and hard drive) on textured floor (duration: 11 seconds)

Once downloaded you can use the standard launch file to play the bag file using:

roslaunch i3dr_deimos deimos.launch device:=rosbag

This will loop and publish the following topics:

tf
i3dr_deimos/left/camera_info
i3dr_deimos/left/image_raw
i3dr_deimos/right/camera_info
i3dr_deimos/right/image_raw

Introduction

Creates a stereo image node pair (left/image_raw and right/image_raw) from any connected Deimos device. This is for compatibility with any other ROS modules which support stereo cameras. This driver has been modified to respect ROS image pipeline conventions and to ease use of the IMU. As per convention, both left and right images are published in the left camera optical frame. IMU data are published in the imu_link frame on the imu_data topic.

The following nodes will be created upon launching this driver.

    /i3dr_deimos/concat
    /i3dr_deimos/image_raw
    /i3dr_deimos/left/image_raw
    /i3dr_deimos/left/camera_info
    /i3dr_deimos/right/image_raw
    /i3dr_deimos/right/camera_info
    /i3dr_deimos/get_brightness
    /i3dr_deimos/set_brightness
    /i3dr_deimos/get_exposure
    /i3dr_deimos/set_exposure
    /i3dr_deimos/imu_data

The Camera preview can be seen using any basic ROS camera application. rqt_image_view can be used for simplicity. To Install and use rqt_image_view

sudo apt-get install ros-jade-rqt-image-view
rqt_image_view

Frames

This package has been updated to conform to the ROS image pipeline frame conventions.

Image conventions in ROS can be a bit confusing, as computer vision usually defines the Z axis to point out of the image, wheras in ROS Z is normally upwards. For this reason cameras define a separate optical frame which is rotated. Note that also both images are published in the left optical frame. This is because typically when using a stereo camera, the right image is effectively ignored. The point cloud is derived and intensity mapped using data from the left camera.

You can see in the URDF file for Deimos - there are two links for each camera. The cameraLeft and cameraRight links are the nominal locations of the image sensors, but the _optical links are rotated in X and Z. This means that when you view the point cloud in RVIZ it should appear the right way up.

TF tree

The full tree for a Deimos system is shown below:

Deimos TF tree

Calibration

You can calibrate the camera using ROS' camera calibration tool. Run the basic launch file with the 'calibrate' parameter:

roslaunch i3dr_deimos deimos.launch calibrate:=true

This will assume you are using an 8x6 calibration board with 0.039m squares. If you have a different board you can specify the settings with the parameters 'grid_rows', 'grid_cols','grid_size':

roslaunch i3dr_deimos deimos.launch calibrate:=true grid_rows:=8 grid_cols:=6 grid_size:=0.039

The calibration display should appear.

See link for details.

Some Tested Examples

To check the exposure of the camera at run time:

rostopic echo /i3dr_deimos/get_exposure

To check the brightness of the camera at run time:

rostopic echo /i3dr_deimos/get_brightness

To change the exposure of the camera at run time:

rostopic pub -1 /i3dr_deimos/set_exposure std_msgs/Float64 "data: <value>"

e.g. :

rostopic pub -1 /i3dr_deimos/set_exposure std_msgs/Float64 "data: 20000"

To change the brightness of the camera at run time:

rostopic pub -1 /i3dr_deimos/set_brightness std_msgs/Float64 "data: <value>"