earthrovers_vision

earthrovers_vision

This package mainly houses the cameras node, which is essentially just a node for grabbing front+rear camera image frames and publishing them to their respective topics.

cameras node

ROS Topics Subscribed

ROS Topics Published

ROS Topic	Interface	Description
front_camera/image_raw	sensor_messages/Image	Most recent front camera frame returned by the Earth Rovers SDK /screenshot endpoint.
front_camera/camera_info	sensor_messages/CameraInfo	Front camera parameters.
rear_camera/image_raw	sensor_messages/Image	Most recent rear camera frame returned by the Earth Rovers SDK /screenshot endpoint.
rear_camera/camera_info	sensor_messages/CameraInfo	Rear camera parameters.

Notes/Disclaimers

• The camera_info being published is most definitely inaccurate / wrong. Those parameters are mostly being used as placeholders, and should be updated with new parameters obtained via calibration (perhaps by following the "How to Calibrate a Monocular Camera" tutorial).
• Right now, the front and rear camera images are being queried via two separate HTTP GET requests to the SDK's /screenshot endpoint. However, because these requests are happening within the same thread, the requests are sequential. The upshot of this is that acquiring images takes longer in total and both the front and rear camera images get published at a lower rate than what might be possible. A future improvement would be to use a MultiThreadedExecutor to parallelize these io-bound, high-latency requests (io-bound, as the SDK currently writes the images to disk).