运行此命令时，单击“校准”，然后提交。显示这样的错误。请帮助我解决这个问题，谢谢。

rosrun camera_calibration cameracalibrator.py --size 8x6 --square 0.108 image:=/usb_cam/image_raw usb_cam:=/start_capture

错误是：

> Traceback (most recent call last):   File
> "/opt/ros/kinetic/lib/python2.7/dist-packages/camera_calibration/camera_calibrator.py",> line 247,in on_mouse
>     if self.do_upload():   File "/opt/ros/kinetic/lib/python2.7/dist-packages/camera_calibration/camera_calibrator.py",> line 204,in do_upload
>     response = self.set_camera_info_service(info)   File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py",> line 435,in __call__
>     return self.call(*args,**kwds)   File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py",> line 495,in call
>     service_uri = self._get_service_uri(request)   File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py",> line 463,in _get_service_uri
>     raise ServiceException("service [%s] unavailable"%self.resolved_name) rospy.service.ServiceException:
> service [/camera/set_camera_info] unavailable