But then you would need an IR camera instead of using the phone's camera. An IR camera should be able to find some hidden cameras passively by detecting a heat source.
not really, no. It'll happily show you IR (just point it at your remote control with the camera active, and press some buttons. Enjoy the light show on your screen that your eyes don't see).
Yes and no. The IR filter is pretty strong. If you have an intense IR source, then it overwhelms the filter, but it would blow out the sensor, without it. The sensor is biased towards IR.
I've converted cameras (DSLRs) to IR, and you use a replacement IR-pass filter. The IR-blocking (default) filter looks like a piece of blue glass. The IR-pass filter looks like a piece of black glass.
It sees it poorly. IR is deliberately (though imperfectly) filtered in the optical path.
The dim purpleish glow from a remote that is seen through [many] digital cameras would be quite bright if this IR filter weren't in place.
It doesn't have to be that way, but it usually is that way anyway -- as a design intent.
Cameras used for surveillance, meanwhile, often lack these filters. They're designed with more of a focus on getting any kind of image at all, including when working with infrared illuminators in the absence of visible light. Some even have mechanical elements that move filters out of the optical path for night mode.
This differs tremendously in comparison to a camera that is designed to produce very beautiful visible-light photographs.
(This all conspires to mean that IR is kind of a non-starter for this sort of cell phone camera hack.)
That was true years ago, but I haven't been able to use an iPhone camera to pick up an IR signal in a long time. Just tested it to be sure they hadn't reverted to an unfiltered lens (17 pro) and nope, no IR visible.
Depends on how cheap you go - most of the cheap ones that take images where the blacks look grey likely do not have an IR filter on them. Most quality phones will use a camera with IR filters on them - blacks look like blacks.
Perhaps to avoid tipping off the entity recording you by blasting their hidden cameras with bright lights. Granted, the PoC device in the article is not exactly subtly looking, but if you could turn it into a sleek device it would be more useful. Not playing your hand while you're under surveillance lets you control the information they're receiving.
Though the bigger issue with my theory is that while most cell phone and webcam devices have IR filters, many surveillance cameras intentionally do not.
If you're being surveilled in a way that you don't want to tip the observers is one thing, but if you're in an AirBnB type place, fuck 'em. I'd even be fine with running some lasers in the place that ruins the sensor.
For now, but there's really no point in detecting them anyway, since there are plenty of truly concealed options for those that really want to be pervs.
Yeah I don’t think this will be effective, cameras can be put in certain angles that it can see with being seen, or how police do it, entirely behind clothes or similar fabric where it can see through and identify but not seen even if you’re looking straight at it.
Great idea though.
I've converted cameras (DSLRs) to IR, and you use a replacement IR-pass filter. The IR-blocking (default) filter looks like a piece of blue glass. The IR-pass filter looks like a piece of black glass.
The dim purpleish glow from a remote that is seen through [many] digital cameras would be quite bright if this IR filter weren't in place.
It doesn't have to be that way, but it usually is that way anyway -- as a design intent.
Cameras used for surveillance, meanwhile, often lack these filters. They're designed with more of a focus on getting any kind of image at all, including when working with infrared illuminators in the absence of visible light. Some even have mechanical elements that move filters out of the optical path for night mode.
This differs tremendously in comparison to a camera that is designed to produce very beautiful visible-light photographs.
(This all conspires to mean that IR is kind of a non-starter for this sort of cell phone camera hack.)
Though the bigger issue with my theory is that while most cell phone and webcam devices have IR filters, many surveillance cameras intentionally do not.
https://people.csail.mit.edu/mrub/VisualMic/