Focusing Problem With Distracting Signal Lights?

A member asked in the IPVMU class today: "I have a scenario where I have PTZs and fixed low light cameras viewing rail track. Recently they installed blue led signal lights for switching and the camera wants to try and focus on those. Any suggestions on resolving this? We are using Bosch PTZs and fixed cameras (498s)." This seems like a tough one. Any ideas?

How about a properly-colored filter to block the blue light? A slight reddish tint should do it - if you can find out the exact wavelength of the LEDs, any good camera shop should be able to tell you (and sell you) the proper tint for maximum effectiveness, so you could use a lower-density filter and reduce the effect on the overall view coloring (AWB may be able to compensate to some degree). As far as masking, I doubt that would work, as I believe most cameras implement masking as an "overlay" on the output video - it would be processed in AFTER the autofocus.
If the PTZ is used with presets, and the PTZ supports this, save the preset after manually focusing. This can stop the AF from trying to focus on the lights.