Display problem with gscam

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Hi everybody,

I am trying to install gscam http://wiki.ros.org/gscam ans I have many problems . First, when I did the command rosrun gscam gscam I had the warning
"Camera calibration file .ros/camera_info/camera.yaml not found."
So I find a camera.yaml and add it. Now I have the warning
"[camera] does not match name ~ in file .ros/camera_info/camera.yaml"
I think I have to add the camera name in the file but I can't find it with lsusb. If someone knows how to find it, it will really help me.

And as it is only a warning, I think I still can run the command. I have something like :

and my webcam is turned on but when I tried to display it with "rosrun image_view image_view image:=/gscam/image_raw" a small blank window pops up, but without any picture or video from my camera.
So I did a "rostopic hz --window=1000 /gscam/image_raw" to see what is published, but there are no messages published by the node.

When I list the topic, I have all topics published by gscam .
/camera/camera_info
/camera/image_raw
/camera/image_raw/compressed
/camera/image_raw/compressed/parameter_descriptions
/camera/image_raw/compressed/parameter_updates
/camera/image_raw/compressedDepth
/camera/image_raw/compressedDepth/parameter_descriptions
/camera/image_raw/compressedDepth/parameter_updates
/camera/image_raw/theora
/camera/image_raw/theora/parameter_descriptions
/camera/image_raw/theora/parameter_updates
/rosout /rosout_agg

And "rosrun rqt_graph rqt_graph" shows me the /gscam_publisher node and the /image_view nodeb and they are not linked.

I don't know what to do. Can somedody help me please?
Thank you