polled_camera Overview

polled_camera defines the ROS interface that client nodes use to request images from a polling camera driver node (e.g. prosilica_camera). The protocol is:

• The camera driver advertises a service call <camera>/request_image of type polled_camera/GetPolledImage.
• The client calls the service, specifying an output namespace.
• On receiving a request, the driver captures an image and returns its time stamp in the service response.
• The driver publishes (latching) the sensor_msgs/Image and sensor_msgs/CameraInfo to <response_namespace>/image_raw and <response_namespace>/camera_info.
• Clients subscribe to the response topics just like any other camera image stream.
• When a disconnection causes the number of subscribers to drop to zero, the publisher shuts down.

See the code API (unstable) for more information on writing polled camera drivers or clients.

There are several reasons for publishing images to topics instead of returning them from the service call:

• Consistency: Client-side processing is always performed in an image callback, regardless of what type of camera is used.
• Visibility: Topics can be monitored in image_view or rviz.
• Reproducibility: Topics can be bagged and played back later.
• Compression: Can take advantage of image_transport to compress images, if desired.

Nodes

poller

Continually requests images from a polled camera at a specified rate in Hz, making the camera look like it is capturing continuously.

Usage:

# Poll "my_camera" at 5 Hz, publishing in namespace my_polled_output/.
$ poller 5 camera:=my_camera output:=my_polled_output

Published Topics

• <output>/image_raw (sensor_msgs/Image) Image topic, actually published by the camera driver. output should be remapped by the user.
• <output>/camera_info (sensor_msgs/CameraInfo) Info topic, actually published by the camera driver. output should be remapped by the user. Services Called
• <camera>/request_image (polled_camera/GetPolledImage) The camera driver’s polled image service. camera should be remapped by the user to the camera namespace.

Changelog for package polled_camera

1.11.13 (2017-11-05)

1.11.12 (2017-01-29)

• Fix CMake of image_transport/tutorial and polled_camera Fix loads of problems with the CMakeLists.
• 1.11.11
• update changelogs
• address gcc6 build error in polled_camera With gcc6, compiling fails with [stdlib.h: No such file or directory]{.title-ref}, as including '-isystem /usr/include' breaks with gcc6, cf., https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129. This commit addresses this issue for this package in the same way it was addressed in various other ROS packages. A list of related commits and pull requests is at: https://github.com/ros/rosdistro/issues/12783 Signed-off-by: Lukas Bulwahn <<lukas.bulwahn@oss.bmw-carit.de>>
• Contributors: Lukas Bulwahn, Martin Guenther, Vincent Rabaud

1.11.11 (2016-09-24)

• address gcc6 build error in polled_camera With gcc6, compiling fails with [stdlib.h: No such file or directory]{.title-ref}, as including '-isystem /usr/include' breaks with gcc6, cf., https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129. This commit addresses this issue for this package in the same way it was addressed in various other ROS packages. A list of related commits and pull requests is at: https://github.com/ros/rosdistro/issues/12783 Signed-off-by: Lukas Bulwahn <<lukas.bulwahn@oss.bmw-carit.de>>
• Contributors: Lukas Bulwahn

1.11.10 (2016-01-19)

1.11.9 (2016-01-17)

1.11.8 (2015-11-29)

1.11.7 (2015-07-28)

1.11.6 (2015-07-16)

1.11.5 (2015-05-14)

1.11.4 (2014-09-21)

1.11.3 (2014-05-19)

1.11.2 (2014-02-13)

1.11.1 (2014-01-26 02:33)

1.11.0 (2013-07-20 12:23)

1.10.5 (2014-01-26 02:34)

1.10.4 (2013-07-20 11:42)

• add Jack as maintainer
• Contributors: Vincent Rabaud

1.10.3 (2013-02-21 05:33)

1.10.2 (2013-02-21 04:48)

1.10.1 (2013-02-21 04:16)

1.10.0 (2013-01-13)

• use CATKIN_DEVEL_PREFIX instead of obsolete CATKIN_BUILD_PREFIX
• fix the urls
• Missing link flags exposed on OS X
• added license headers to various cpp and h files
• Contributors: Aaron Blasdel, Dirk Thomas, Vincent Rabaud, William Woodall

1.9.22 (2012-12-16)

• replace genmsg by message_generation
• Contributors: Vincent Rabaud

1.9.21 (2012-12-14)

• Updated package.xml file(s) to handle new catkin buildtool_depend requirement
• Contributors: mirzashah

1.9.20 (2012-12-04)

1.9.19 (2012-11-08)

1.9.18 (2012-11-06)

• remove the brief attribute
• Contributors: Vincent Rabaud

1.9.17 (2012-10-30 19:32)

• comlpy to the new catkin API
• Contributors: Vincent Rabaud

1.9.16 (2012-10-30 09:10)

1.9.15 (2012-10-13 08:43)

• fix bad folder/libraries
• Contributors: Vincent Rabaud

1.9.14 (2012-10-13 01:07)

• fix typo that resulted in bad installation of include folder
• Contributors: Vincent Rabaud

1.9.13 (2012-10-06)

1.9.12 (2012-10-04)

1.9.11 (2012-10-02 02:56)

1.9.10 (2012-10-02 02:42)

1.9.9 (2012-10-01)

• fix dependencies
• Contributors: Vincent Rabaud

1.9.8 (2012-09-30)

• add catkin as a dependency
• comply to the catkin API
• Contributors: Vincent Rabaud

1.9.7 (2012-09-18 11:39)

1.9.6 (2012-09-18 11:07)

1.9.5 (2012-09-13)

• install the include directories
• Contributors: Vincent Rabaud

1.9.4 (2012-09-12 23:37)

• make sure we depend on the server
• Contributors: Vincent Rabaud

1.9.3 (2012-09-12 20:44)

1.9.2 (2012-09-10)

1.9.1 (2012-09-07 15:33)

1.9.0 (2012-09-07 13:03)

• catkinize for Groovy
• polled_camera (rep0104): Changed callback to allow filling status_message field.
• polled_camera (rep0104): Applied changes to GetPolledImage service.
• Contributors: Vincent Rabaud, eitan, gerkey, kwc, mihelich