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by Construct 5472 days ago
It depends on 1) the IR attenuation of the filter and 2) the sensitivity of the camera element to IR.

IR filters can only attenuate incoming IR so much while still allowing nearby red wavelengths through. And any filter will have a non-flat response through the visible wavelengths, slightly distorting the color response of your photos.

A properly coded IR signal from the transmitting 'disabler' device could still be picked up by the iPhone even if it was severely attenuated. At ~30fps, you can quickly get 100+ samples to cross-correlate with to search for the encoded 'disable' signal.

My gut feeling is that Apple patented this technology because it was low-hanging fruit. They saw they could roll it into a legitimate patent and prevent others from claiming it down the road. Still, I think it's worthwhile to send a quick letter to the powers that be to let them know we all disprove. If it does get implemented, the popularity of jailbreaking will move up another notch.
2 comments
pavel_lishin 5472 days ago
> If it does get implemented, the popularity of jailbreaking will move up another notch.

Unless they implement it at the hardware level.

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jrockway 5472 days ago
If only there were multiple suppliers of mobile phones.
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georgieporgie 5472 days ago
A properly coded IR signal from the transmitting 'disabler' device could still be picked up by the iPhone even if it was severely attenuated.

How about IR filter + 555 timer connected to an IR LED near the camera lens. Filter down the unwanted IR signal, then wash it away with a flood of intermittent IR of your own.

At ~30fps, you can quickly get 100+ samples to cross-correlate with to search for the encoded 'disable' signal.

Can you explain how that works? I don't have a deep grasp of CCDs, so I don't understand how a signal like this could be encoded within a single 1/30 second frame. I thought that all pixels were captured simultaneously, is that not the case?

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wnight 5471 days ago
No, they simply mean that you quickly gather many whole frames and even if the signal is mostly lost in most of them, enough would remain.
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