Contents
Usage
Viewing a single image topic
rosrun image_view image_view image:=<image topic> [image transport type]
For example, to view raw images on the topic /camera/image, use:
rosrun image_view image_view image:=/camera/image
You may save the current image by right-clicking on the display window. By default, images will be saved as frame0000.jpg, frame0001.jpg, ....
If you want to view a compressed image stream (usually a good idea over wireless!) using the capabilities of image_transport, specify the transport type as a command-line argument. For example, if theora_image_transport is built on the publisher's side, you can use theora transport:
rosrun image_view image_view image:=/camera/image theora
Note that this is merely shorthand equivalent to setting the ~image_transport parameter:
rosrun image_view image_view image:=/camera/image _image_transport:=theora
Viewing stereo images
rosrun image_view stereo_view stereo:=<stereo namespace> image:=<image topic identifier>
For example, to view stereo image pairs on topics /my_stereo_cam/left/image_rect_color and /my_stereo_cam/right/image_rect_color, use:
rosrun image_view stereo_view stereo:=/my_stereo_cam image:=image_rect_color
stereo_view also shows the disparity image computed from the stereo pair, color-mapped for clarity.
You may save the current image pair by right-clicking on any display window. By default, images will be saved as left0000.jpg, right0000.jpg, disp0000.jpg, left0001.jpg, right0001.jpg, disp0001.jpg.... As with image_view, you can specify an image transport to use for the left and right image as an optional argument.
Nodes
image_view
Simple image viewer for ROS sensor_msgs/Image topics.Subscribed Topics
image (sensor_msgs/Image)- The image topic. Should be remapped to the name of the real image topic.
Parameters
~autosize (bool, default: false)- Whether the window should autosize itself to the image or be resizeable by the user.
- printf-style format for saved image names. Use to control name, location and format of saved images.
- Transport used for the image stream. image_view allows you to specify this as a simple command-line argument for convenience.
- The name of the display window.
disparity_view
Simple viewer for stereo_msgs/DisparityImage topics. Color-maps the disparity image for visualization.Subscribed Topics
image (stereo_msgs/DisparityImage)- The disparity image topic. Should be remapped to the name of the real topic.
Parameters
~autosize (bool, default: false)- Whether the window should autosize itself to the image or be resizeable by the user.
- The name of the display window.
stereo_view
Viewer for stereo images. Shows the synchronized left/right image pair and the disparity image (color-mapped) computed from them.Subscribed Topics
<stereo>/left/<image> (sensor_msgs/Image)- The left image topic. Formal parameters stereo and image should be remapped appropriately.
- The right image topic. Formal parameters stereo and image should be remapped appropriately.
- The disparity image computed from the left/right stereo pair.
Parameters
~autosize (bool, default: true)- Whether the windows should autosize to the image or be resizeable by the user.
- printf-style format for saved image names. Use to control name, location and format of saved images. The string argument is "left" or "right".
- Transport used for the image streams.
- Whether to use approximate synchronization. Set to true if the left and right cameras do not produce exactly synced timestamps.
- Size of message queue for each synchronized topic. You may need to raise this if disparity processing takes too long, or if there are significant network delays.
Nodelets
image_view/image
Nodelet version of image_view. Brings up a display window for a sensor_msgs/Image topic.Subscribed Topics
image (sensor_msgs/Image)- The image topic. Should be remapped to the name of the real image topic.
Parameters
~autosize (bool, default: false)- Whether the window should autosize itself to the image or be resizeable by the user.
- printf-style format for saved image names. Use to control name, location and format of saved images.
- Transport used for the image stream. image_view allows you to specify this as a simple command-line argument for convenience.
- The name of the display window.
image_view/disparity
Nodelet version of disparity_view. Brings up a display window for a stereo_msgs/DisparityImage topic, color-mapped for visualization.Subscribed Topics
image (stereo_msgs/DisparityImage)- The disparity image topic. Should be remapped to the name of the real topic.
Parameters
~autosize (bool, default: false)- Whether the window should autosize itself to the image or be resizeable by the user.
- The name of the display window.
Tools
image_saver
This tool allows you to save images as jpg/png file from streaming (ROS sensor_msgs/Image topic) to a file. From command line, you can run by rosrun image_view image_saver image:=[your topic], or see this answer to control the timing of capture.Subscribed Topics
image (sensor_msgs/Image)- The image topic. Should be remapped to the name of the real image topic.
Services
save (std_srvs/Empty)- Save images, you need to set save_all_images to false
Parameters
~filename_format (string, default: left%04d.%s)- File name for saved images, you can use '%04i' for sequence number, and '%s' for default file format, you can use 'jpg' ,'png', 'pgm' as filename suffixes.
- Encoding type of input image topic.
- If you set false, images are only saved when 'save' service is called
extract_images
This tool also allows you to save images as jpg/png file from streaming (ROS sensor_msgs/Image topic) to a file. image_saver node provide very similar functionalities, such as providing service call to trigger the node to save images, save images other than Jpeg format, etc.Subscribed Topics
image (sensor_msgs/Image)- The image topic. Should be remapped to the name of the real image topic.
Parameters
~filename_format (string, default: frame%04d.jpg)- File name for saved images, you must add use '%04i' for sequence number.
- set sec per frame value.
video_recorder
This tool allows you to record a video stream (ROS sensor_msgs/Image topic) to a file. It relies on OpenCV's VideoWriter class. With the default options, it encodes the video as MPG, encapsulated in a AVI container at 15 fps, and produces a file called output.avi in the current directory.Subscribed Topics
image (sensor_msgs/Image)- The image topic. Should be remapped to the name of the real image topic.
Parameters
~filename (string, default: output.avi)- Path and name of the output video.
- Framerate of the video.
- The FOURCC identifier of the codec.
- The image color space of the video.
