I guess almost everyone knows about the really small area of electromagnetic spectrum that humans are able to see.
Well, it is just not fair :-).
Why there is still no multi spectral (means with variable spectrum) visors available on the market ?
The idea is to get an predefined by device settings spectrum area (can be changed at any time by user) and map it to common RGB palette in order to visualize all the spectrum.
Are there any unsolved technological problems or restrictions with that ?
What areas of spectrum are still difficult/unavailable to observe ?
As far as I understand this kind of device is quite simple and is just a simple modification of common cell phone camera (so it is cheap for mass production).
No doubt, this kind of device will reveal a lot of great hidden info on EM interactions from the world that will be easy to observe in dynamics and will be quite useful for lots of people in all areas from science to applications. I guess it will be a revolution in technics/biology related areas or natural sciences (and also a good device to common use).
For more discussions on this topic – take a look at stack physics