Re: Clarification on RGB and Depth image has input from Stereo camera

Posted by matlabbe on
URL: http://official-rtab-map-forum.206.s1.nabble.com/Clarification-on-RGB-and-Depth-image-has-input-from-Stereo-camera-tp2469p5029.html

Hi,

The standard ROS way is to send the left and right images to stereo_img_proc, to get the disparity image. The disparity image can then be fed to disparity_to_depth nodelet to convert to a depth image.

The message type sensor_msgs/Image is not convenient to represent disparity images (well, it could for compression purpose). To convert to depth we need the baseline and focal distance, which sensor_msgs/DisparityImage has directly. To convert disparity from a sensor_msgs/Image we would have to subscribe also to left and right camera_info to get the baseline and focal distance required to convert disparity values (pixels) to depth values (meters or mm).

cheers,
Mathieu