Edit 2: Tested on iPhone 15 Pro selfie camera. It detects IR at the same intensity.
Edit 3: Same as above with a Pixel 8.
Edit 4: I now have my office involved, this is fun. Same with a Samsung S24.
Final Edit: OK, I just went through about 20 colleague's phones, which are various mixes of iPhone and Android, new and old. Testing the front and back camera, every camera on every phone saw the IR light.
If a smartphone camera does not see IR light, this appears to be the exception, not the rule. OK, back to work!
These are all US devices, in case that matters. We don't seem to have an agency that regulates light emissions from cell phones.
I've always been fascinated by this topic as well. As a further experiment, you may be interested to know that these IR lights can pass straight through red wine that looks totally dark and opaque to the human eye. I took some photos to demonstrate this with a DSLR with the IR filter removed here [1], but you can test this yourself by using a smartphone to look at the IR light of a TV remote with a glass of red wine in between them.
I've been pondering some sort of "night vision"[1] system for my car after noticing how excellent low light is on my VIOFO dash cam.
The dash cam has a video-out port, but unfortunately it appears to be NTSC resolution. I'd love some sort of setup that outputs to >=8" 1080p display attached to my dash. It would help so much in my rural area with wildlife in the road, as well as the constant random pedestrian walking on an unlit rural highway in dark clothing.
Ideally, if I could get great quality, low noise low light video like the VIOFO, I could then start playing with object identification with OpenCV.
1. I worked on such spectral systems in a past military life but don't want to attach something big like a Cadillac FLIR unit, or something expensive, like nearly every viable consumer FLIR option. All the "affordable" consumer FLIR options suffer from low resolution and/or low response time.
> All the "affordable" consumer FLIR options suffer from low resolution and/or low response time.
When I experimented with connecting two thermal cameras to a VR headset for stereo thermal vision, I used two Seek CompactPRO FastFrame units. They're 320x240@15Hz for $400 which is a lot more usable than the typical 80x60@9Hz consumer thermal, and it's easy to integrate the Android model into custom applications. They also have a 320x240@25Hz model for $1000.
I'm still impatiently waiting for affordable 640x480 thermal cameras, but in my opinion 320x240 at moderate frame rate is past the good-enough threshold to be legitimately useful for high contrast situations like identifying warm-blooded life on the side of a rural road.
> I'd love some sort of setup that outputs to >=8" 1080p display attached to my dash.
The Tesla Cybertruck has an option to display the view from the front bumper camera on the 18.5" main screen, but front camera display is unfortunately not available in any of Tesla's other models. With the proliferation of large touchscreens and camera arrays, more vehicles may support this from the factory soon.
"Infra-red" covers a bunch of wavelengths. 'Near Infra-red' is very close to visible light, and is what's used by remote controls and picked up by cell phone camera sensors. It's around the 0.75–1.4 μm range. On the other hand, thermal cameras are sensitive to 'Long-wavelength infrared' which is around 8–15 μm wavelength.
Marketers of things like CCTV cameras love to sow confusion about these things, as NIR-sensitive cameras are extremely cheap while thermal cameras are comparatively expensive.
Humans are not sensitive to NIR because for the vast majority of human existence, any time there was NIR light there was also an abundance of normal visible light, due to a little thing called "the sun"
Non-shit night vision, the kind where warm things glow at night, requires LWIR sensors that are at a temperature lower than the warm thing (otherwise the sensor itself glows).
NIR sensitivity does not improve night vision. That mostly requires a "tapetum lucidum" or reflective layer, more rods than cones (less helpful when you want to see colors in daylight) or just larger, more biologically expensive and vulnerable eyes than necessary.
Your comment and its grandparent are both excellent, but I would like to nitpick a bit here. Technically, NIR sensitivity does improve night vision through the simple mechanism of "detect more wavelengths = detect more total light". It's not thermal imaging, but it is the reason that CCTV cameras often mechanically move their IR filter out of the way when the light falls below some threshold - at that point, sensitivity is more important than color fidelity, so they accept all the light they can get, even nonvisible. Of course this is also often coupled with NIR illumination LEDs.
