High CPU usage in stereo_camera_node

[YipuZhao]

When running the stereo_camera_node in ros, I can't help notice that it takes 2 cores (~200% CPU usage). Based on stereo_camera_node.cpp, it seems to only grabbing and publishing data from the sensor; which shouldn't take much computation power.

Is there any background processing when running stereo_camera_node? If I just want to grab the raw video stream (no rectification, no stereo matching), is there a way to do so?

Thanks for any suggestion!