Camera "Colour Rolling" on Three Phase

[RobOwen]

I've got a few security cameras that we put up in a showroom, all are fine except the ones located where there are fluorescent tubes on different phases from eachother.

 

If the camera sees two sets of flourescent lights on different phases the camera goes yellow over one set and then fades yellow over the other set. At some point in the cycle both sets of lights appear white.

 

If just one set are turned on then the camera locks perfectly and doesn't cycle yellow, as soon as the other set are turned on the cycling happens again.

 

Is there a way to lock the power supplies of the cameras or something so that the yellowing doesn't happen, some sort of power conditioner maybe?. Sometimes the swopping is fast, other times it is slow.

 

 

Any suggestions much appreciated.

[boatman]

There's not much you can do with the power supplies. Unfortunately, the mains frequency is 50Hz and the camera frame frequency is also 50Hz (or thereabouts), but being crystal controlled will be very slightly different from the mains frequency. So, what you are seeing is the aliasing between the two.

 

If your cameras can accept an external frame sync locked to the mains you'll be able to fix it, otherwise you'll have to switch to tungsten lighting which doesn't flicker like flourescent tubes.