[ros-users] how to publish JPEG images with compressed_image_transport ?
Rene Ladan
r.c.ladan at gmail.com
Fri Mar 26 15:18:49 UTC 2010
It works now, with the leading underscore :-) The rest was correct after all.
The topic list also has changed:
%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
* /jpeg/image/compressed [sensor_msgs/CompressedImage] 1 subscriber
* /rosout [roslib/Log] 1 subscriber
* /clock [unknown type] 3 subscribers
Thanks,
Rene
2010/3/26 Rob Wheeler <wheeler at willowgarage.com>:
>> %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)
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>>>>
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