can't detect QR code for ROS camera image in Gazebo

[stevensgeek41]

I was using quirc lib in ROS simulation and everything goes smoothly excepts that it cannot detect any qr code I put in the gazebo simulation environment. I don't know if it's because the conversion between ROS sensor_msgs/Image topic and quirc image goes wrong or because the gazebo simulated image is not "real" enough. Any idea?
The gazebo image looks as follows:

[stevensgeek41]

case closed. Turns out the drone needs to be near enough to the code and the code should be exposed by the light.