problem with visp_auto_tracker

edit

Hi i have successfully run the auto tracker, but it seems like run much slower than example videos shown in ros_wiki.

the example video: https://www.youtube.com/watch?v=_dFF0...

my video: https://youtu.be/8PRvELsXeYI

the frequency of /image_raw is 30 Hz, image_height x image_width is 640x480, when i run the

rostopic echo /visp_auto_tracker/code_messgae

I got:

data: ''
---
data: http://www.irisa.fr/lagadic/visp
---
data: ''
---
data: http://www.irisa.fr/lagadic/visp
---
data: ''
---
data: http://www.irisa.fr/lagadic/visp
---
data: ''
---
data: http://www.irisa.fr/lagadic/visp
---
data: ''
---
data: http://www.irisa.fr/lagadic/visp
---

there is a empty message every two messages (ps: no matter how i place the QRcode, the empty message exist)

much thanks if anyone can give some help!