[ros-users] how to publish JPEG images with compressed_image_transport ?

[Rob Wheeler]

> %rosrun image_view image_view image:=/jpeg/image image_transport:=compressed

image_transport is a parameter on the master, so it should have a
leading underscore (http://www.ros.org/wiki/Remapping%20Arguments)

Try:

%rosrun image_view image_view image:=/jpeg/image _image_transport:=compressed

On Fri, Mar 26, 2010 at 3:35 AM, Rene Ladan <r.c.ladan at gmail.com> wrote:
> Hi,
>
> the attached C++ file publishes a JPEG picture from disk on
> /jpeg/image/compressed
> (verified with rostopic list -v).  However, if I run image_view to
> display the picture, I only get
> a blank window. There seems to be a discrepancy:
>
> %rostopic list  -v
>
> Published topics:
>  * /rosout [roslib/Log] 2 publishers
>  * /rosout_agg [roslib/Log] 1 publisher
>  * /jpeg/image/compressed [sensor_msgs/CompressedImage] 1 publisher
>
> Subscribed topics:
>  * /time [unknown type] 3 subscribers
>  * /rosout [roslib/Log] 1 subscriber
>  * /clock [unknown type] 3 subscribers
>  * /jpeg/image [unknown type] 1 subscriber
>
> Comands invoked:
> %roscore (with ROS_IP set to public IP address and ROS_MASTER_URI to
> http://localhost:11311)
> %rosrun pkg-name jpeg
> %rosrun image_view image_view image:=/jpeg/image image_transport:=compressed
>
> So there is probably something wrong with the code, but the unknown
> type /jpeg/image in the
> subscriber list also looks suspicious?
>
> Regards,
> Rene
>
> 2010/3/16 Jeremy Leibs <leibs at willowgarage.com>:
>> The axis_camera node in the texas_drivers stack does exactly this.
>>
>> https://code.ros.org/trac/wg-ros-pkg/browser/stacks/texas_drivers/trunk/axis_camera/axis.py
>>
>> The relevant snippets (python code, but C++ would be almost identical):
>>
>> Create the appropriate publishers ("compressed" and "camera_info"
>>
>>    self.pub = rospy.Publisher("axis_camera/compressed", CompressedImage, self)
>>    self.caminfo_pub = rospy.Publisher("axis_camera/camera_info",
>> CameraInfo, self)
>>
>>
>>
>> Populate the appropriate messages and publish:
>>
>>      img = fp.read(content_length)
>>
>>      msg = CompressedImage()
>>      msg.header.stamp = rospy.Time.now()
>>      msg.format = "jpeg"
>>      msg.data = img
>>
>>      self.axis.pub.publish(msg)
>>
>>      cimsg = CameraInfo()
>>      cimsg.header.stamp = msg.header.stamp
>>      cimsg.width = self.width
>>      cimsg.height = self.height
>>
>>      self.axis.caminfo_pub.publish(cimsg)
>>
>>
>> On Tue, Mar 16, 2010 at 7:10 AM, Rene Ladan <r.c.ladan at gmail.com> wrote:
>>> Hi,
>>>
>>> I'm writing a node to publish images from the Surveyor stereo camera
>>> (see http://www.surveyor.com/stereo/ ).
>>> The camera publishes the images in JPEG format.  The logical thing
>>> would be to somehow feed them to the
>>> compressed_image_format node (after setting up a handmade header?) to
>>> publish them.  Is there any example
>>> code which does this?
>>>
>>> Also, if I understand correctly, the subscriber can just subscribe to
>>> the normal image_transport topic, but needs
>>> to have extra code to decompress compressed images before using them?
>>>
>>> Thanks,
>>> Rene
>>> --
>>> http://www.rene-ladan.nl/
>>>
>>> GPG fingerprint = E738 5471 D185 7013 0EE0  4FC8 3C1D 6F83 12E1 84F6
>>> (subkeys.pgp.net)
>>> _______________________________________________
>>> ros-users mailing list
>>> ros-users at code.ros.org
>>> https://code.ros.org/mailman/listinfo/ros-users
>>>
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