I am using the viso2ros package, which provides the ros wrappers for the Visual Odometry package libviso2, to track a moving monocular camera. For this purpose I am using the Asus Xtion Pro which directly generates both mono and rgb image topics. Then I am also running the imageproc node to rectify those images. After that I am running the monoodometer node of the viso2ros package. However the viso2_ros doesn't seem to be publishing any values. The "rostopic list" gives the pose and odometry topics, however echoing them shows nothing, indicating the topics are empty. I cannot figure out why ? Can anyone help me point out where the problem lies?