Unidentified object on a bone dome

[STURM]

Does anyone know what is that circular object mounted on the right of the pilot's bone dome?

[nomedia="http://www.youtube.com/watch?v=Nktq3_VmELk"]RMAF Sukhoi Su-30MKM air demonstration LIMA 2013 - YouTube[/nomedia]

 

[south]

Looks like a Velcro patch to me....

 

[Bronco46]

Helmet Object.

Could that be some kind of laser or infrared target for a smart helmet?

 

[LeGrig]

Object attached to the canopy-frame

It is a mirror (not really circular shape - but rectangular). The pilot is reading it during taxi. Possibly, for the trainer version, the rear seat obturates vue to the control surfaces. I have seen it on the trainer version only.