image detection

hi all... i have one enquiry.. there is one welding machine.. in that welding machine i put one cylindrical object...on that object one image is present.. image is ARROW(-->) ..ok..if i put this object in wrong direction ie the arrow is like this(<--)...then welding should not be done unless the object should be proper direction... so what i want to ask that which device i use to detect an image on the object and how to configure device for correct image.
which is the cheapest option for this..

I have used ifm/efector dualis for similar applications.
Banner presence plus or banner iview may work.
I haven't setup either in years so I don't know of new/changed functionality of either.

thank you sir,
can you give me type number of sensor.. so i can read details information about this i.e. cost, availability, etc
Waiting for your reply

Cognex has the Checker range of sensors which can do this type of job also.