Color Night Vision (2016) [video]
kottke.org
kottke.org
But - this is an 'area under the graph' issue. While it may peak at 60%, it can also fall off quickly and be much less efficient as the wavelength moves away from the peak for say red/green/blue.
From what I can tell from the tacky promo videos, the sensor is very sensitive for each colour over a wide range of wavelengths, probably from ultraviolet right up to 1200nm. That's a lot more photons being measured in any case, but especially at night.
Their use of the word 'broadband' sums it up. It's more sensitive over a much larger range of frequencies.
I also wouldn't be surprised if they are using a colour filter array with not only R/G/B but perhaps R/G/B/none or even R/IR/G/B/none. The no filter bit bringing in the high broadband sensitivity with the other pixels providing colour - don't need nearly as many of those.
Edit - one remarkable thing for me is based on the rough size of the sensor and the depth of field in the videos, this isn't using a lens much more than about f/2.4. You'd think it would be f/1.4 or thereabouts to get way more light but there is far too much DoF for that.
At nonzero temperature, you have the further problem that your sensor has thermally excited electrons, which aren't necessarily a problem AFAIK. More importantly, the sensor glows. If the sensor registers many of its own emitted photons, you get lots of thermal noise.
Good low noise amplifiers for RF that are well matched to their antennas can avoid amplifying their own thermal emissions. I don't know how well CCDs can do at this.
Given that this is a military device, I'd assume the sensor is chilled.
My understanding is that the human eye has a surprisingly high quantum efficiency (about 12 to 30 % of photons are detected), and that the reason night looks dark is because there really aren't that many visible spectrum photons around.
My guess is that this camera is physically enormous.
Edit: Apparently, it's really small! I am dumbfounded. Then again, I guess it could have a hundred times the area of a human pupil and still be pretty small.
As to the technical question according to this you need 90 photons for a 60% chance at a human response
http://math.ucr.edu/home/baez/physics/Quantum/see_a_photon.h...
Not entirely true. Assuming an incoherent source, conventional optics, and a well-defined frame (i.e. you measure for a time t and the source is unchanging for the whole time), you have a bunch of modes of incoming light that would hit each pixel. Measuring these modes in the photon number basis isn't optimal. The ideal measurement is probably something quite different. It may also depend on your exact assumptions avoid the source.
With coherent light it can be useful to have the light interact with matter in a way that depends on the phase of the light. But if the light is incoherent then that won't yield anything useful. And this still doesn't beat the shot noise limit - your phase measurements still come from counting photons subject to shot noise.
Then there's polarisation. Two polarisation states. But really that's just like saying there are two kinds of photons. Both polarisation states are subject to number-phase uncertainty principle.
I think that's it. There's the number and phase, which are conjugate variables. You can make number more accurate by squeezing phase, but only if you control the light source. And then there's the two polarisation states.
And the EM field simply doesn't have any more degrees of freedom than that, so I think that's it unfortunately.
It's number-phase squeezing or nothing if you want to count photons more accurately than shot noise.
Second, nocturnal animals like howls see very well in the dark. Granted, they don't see colors but they still show that in theory seeing in the night is physically impossible.
PS. regarding the collecting area, something I've been wondering for a bit : isn't the number of photons a lens can capture proportional to the square of the surface and not the surface itself? I know that sounds counter-intuitive but with interference, quantum mechanics and stuff, I checked the math once and I could not see where I was wrong.
It also seemed to make sense to me otherwise we would not need to build large telescopes, we could just build lots of small ones and fuse the images.
No.
Light is a wave and a particle, and if you are getting wildly different answers from thinking about it as a wave and as a particle, and you're looking at a macro and not micro scale, then you're doing it wrong. That's why I answered your wave question with a photon count answer.
But how do you count photons without using probability amplitudes? If you count them by using a classical reasoning of photons being small particles falling from the sky, I'd say you're doing it wrong, because photons are not classical particles.
Many distant things, like galaxies, are very dim. M31 is almost visible to the naked eye, which is not dim to an astronomer. You might want to study astronomy before having strong opinions about it.
However I'm not sure whether the total number of photons collected is the right thing to be measuring. Aren't there serious aberrations at high magnifications in practice?
And aren't there, y'know, glowing objects in the night sky? Stars I believe? The moon? I don't know how many photons there are but a single green photon carries a miniscule 376 zeptojoules and I don't think my eye responds to anything below the picojoule range. Counting photons and looking for the information limit seems a little extreme in this, er, light.
I wonder whether you could use this technology for medical imaging if you shield the camera from any light that isn't being transmitted through the body. The possibility of recovering color information is exciting.
If you keep the setup such that all the light that comes through the lens will get to the sensor, and keep the sensor the same size, a larger lens would mean a higher brightness, right? Maybe in practice you're limited by other factors, but 'nothing' can't be right. Especially when we're talking about theoretical limits.
Edit: I think what you're saying is that the lens doesn't matter for the brightness if you scale the focal length and sensor size in such a way that the brightness stays the same. Which is obviously true, but if you leave out the last part, it isn't.
2 pulses encode a signal that's a factor higher than a 1 pulse signal.
You see this limitation in the video as well. That CCD video, the one with some vision and color but huge amounts of noise, I feel you see that it's clamping to some limited domain. Increasing it's range would improve things a lot.
True, but that's because as far as we know they evolved on a very low light world orbiting a red dwarf star. They're not actually nocturnal on their homeworld.
They also supplement their incredible night vision with sonar that's in the audible range for humans, hence their name.
That's a much higher QE than the good old days, wow.
I knew it was over 60%, and I remembered (wrong) as the G15 and G16 having the same sensor. Welp, 77% QE for the G16 and 67% for the G15. There are others with higher QE, though in general those are used in smaller sensors.
DSLRs, while having lower QE numbers, have much larger sensors, and hence a better image quality.
(Sony) Alpha-900 234% 3.6 892070
(Pentax) Q 101% 1.6 8429
There's a few more.
Pretty fascinating!
As for those saying about the over 100% QE numbers... I didn't gather those, all I can say that a few years back that list was accepted as generally reasonable measurments.
Besides that, I've read of some imaging techniques which can form images with a really low number of photons (for example [0]), but those generally require a special setup (infrared light, lasers, that sort of stuff). So yeah, those QE's do seem fishy, but it could alse be the result of a photon affecting more than one photosite (or maybe the marketing team hearing about QE and finding a way to raise that number through "smart counting").
There's a promo video of the manufacturer. At 0:16 you can see something looking like cooling fins on the side. https://youtu.be/c_0s06ORTkY?t=16s
https://www.youtube.com/watch?time_continue=328&v=c_0s06ORTk...
Anecdotal evidence on the internet suggests it's around £6k, but that seems far too low.
Here is SWIR used to see through smoke:
- https://www.youtube.com/watch?v=GUUIgBut8RU
- https://www.youtube.com/watch?v=keRxJg-gjLE
- LWIR, MWIR, SWIR (long/medium/short wavelength infrared): https://www.youtube.com/watch?v=3pfzO26a21c and https://www.youtube.com/watch?v=iV4hNzDJbF0
- Overview SWIR cameras and applications: https://www.youtube.com/watch?v=Vi0x7D5u7Dk
Use cases for such cameras go way beyond night vision, see @5:13 in the last video for a list.
For Special Operations use, it'd be nifty to have this technology digitally composited in real-time with MWIR imaging on the same wearable device. Base layer could be image intensification with this tech, then overlay any pixels from the MWIR layer above n temperature, and blend it at ~33% opacity. Enough to give an enemy a nice warm glow while still being able to see the expression on their face. Could even have specially made flashbangs that transmit an expected detonation timestamp to the goggles so they know to drop frames or otherwise aggressively filter the image.
Add some active hearing protection with sensitivity that far exceeds human hearing (obviously with tons of filtering/processing), and you're talking a soldier with truly superhuman senses.
That's not to mention active acoustic or EM mapping techniques so the user can see through walls. I mean, USSOCOM is already fast-tracking an "Iron Man" suit, so I don't see why they wouldn't want to replicate Batman's vision while they're at it.
I believe this is what CAT did with their S60 phone camera - fusing together the image of the thermal sensor and the camera to have a high-resolution thermal image even without an expensive-as-hell sensor.
See the two images of an SUV (the top one has caption "Color Low Light Night Vision Midnight Image Fused with thermal infrared RED ALERT FLIR Image") on the product page [1].
They do... the OP points to a product sold to military.
The US government develops its military technology buy giving companies like this R&D grants and then buying their product.
It rather feels like it's rapidly coming apart, but that's seemingly okay for many people because you can just have a short position...
All things considered, you might not need to...
You're already in the future, man!
Ugh, no thanks.
I keep running into this sort of crud from Sony.
https://www.schneier.com/blog/archives/2005/11/sonys_drm_roo...
Do they ever learn?
1. It would be nice to see a split screen against a normal view of the scene as it would be seen by the typical naked eye.
2. Our light pollution must SUCK for nocturnal animals that see well at night.
This camera goes to ISO 5 million, which is awesome.
A split-screen view, with half the screen in pitch black wouldn't illustrate much.
Watch when the camera tilts upwards and you see all the stars.
So, if I get this right this uses residual light from the stars and other sources to do the imaging, and judging by the speed of the update it's doing that with so short an exposure that you'd never even realize that if it wasn't mentioned.
That's one hell of a sensor, and probably quite a bit of on-board post-processing.
There is a starlight video on that page:
You can see that nebula with the naked eye, but you need a pretty dark sky. I'm pretty sure it was not naked-eye-visible under that sky. Awesome camera.
https://www.x20.org/wp-content/uploads/2015/09/true-color-ni...
Maybe 6" horizontal and 4" vertical and the sensor smaller than that.
https://www.x20.org/wp-content/uploads/2015/09/IMG_0041.jpg
Judging by the pitch of the pads at the bottom that's about 2" wide and 1.5" tall.
They sold tiny wireless spy cameras or something, but most famously, were at one point almost synonymous with "Internet banner ads".
I remember a song "We must destroy X10!", which was protesting against the rising ubiquitousness of Internet banner ads (in general, although the X10 ads really were everywhere back then).
If they can increase the dynamic range to bring detail to the highlights it is basically perfect.
I've never seen a valley look like that with a blue sky above with stars in it. Truly incredible.
The 5M ISO rating is pretty funny. 1/40 f1.2 ISO 5M.
However at night the headlight fan on the road is detail-free. This could be improved.
That was what I meant saying the DR could improve.
Thinking about it some more from a technical perspective ( and I know absolutely nothing about the technology in this field ) it seems the camera really suffers from strong point light sources ( headlights, streetlamps, so on ), and I know that these sources often have specific known spectral characteristics ( color temperature and so on ) -- and I'm wondering if a way to improve the performance here is to somehow detect the spectral signatures of a range of such light sources, and somehow cap the contribution these can make to the brightness in the image...so preventing these highlights from burning out the details, and increasing the apparent dynamic range -- even when the camera is pointed down road ahead of a vehicle with headlights on.
I like the production values of that video. The (appropriately, for this product) triumphant music. The long blank-face titles with abstract technical terms, concrete locations and hard-boiled scene descriptions: "Human in desert". Then cut to some shot of guy walking away from the camera in the desert alone under starlight. In full color. Sort of new wave cinema.
Not at all suggesting any fakery with this next comment but I am wondering how the humans in the videos didn't trip over bushes and things. Maybe they edited that stuff out, or their natural night vision was warmed up.
Holy shit, my Canon 600D is pretty bad at 2500, goes to crap at 3200, and 6400 is an absolute noise mess…
http://www.kenrockwell.com/sony/a7s-ii.htm
EDIT: fixed the actual ISO.
Basically we need 600 times more light. Square root of 600 is about 25. So you'd need a lens system with an initial aperture 25 times larger in diameter than the one you used to do the long exposures.
Big lens, but if you want to brute force this kind of problem, that's the way to do it!
It's easily possible to grind your own big telescope mirror. A big lens is like trying to build a big refracting telescope -- extremely expensive. The largest refracting telescope ever made is 100cm (40 inches). Mirrors are up to 10 meters.
TMI: I have an autoimmune disease affecting my skin that my care givers have attempted to track with photos over the years. It's not very effective. But with just human eye and just the right lighting, its much easier to see what's what. Sun light vs florescent, angle vs straight on.
But they are expensive. 640x480 can cost over 10000 USD and cameras with smaller resolution like those used in high-end cars still cost over thousand USD.
I've used the first one- resolution is quite low, but a few years ago you couldn't even buy such sensors as a hobbyist (example image: http://faili.wot.lv/tmp/IMG_20160320_163431.jpg)
These are the same sensors which are used in FLIR smartphone-attached thermal cameras.
Otherwise with any direct source of light in an image it would immediately overexpose (in some low light cameras that could even damage the sensor). It's super impressive.
Or this was shot during full moon, carefully avoiding it getting in sight? Then it is not much better than (fully adapted) naked eye.
PS: probably wrong about that, silicon's band gap is more suited to optical spectrum, even though germanium has more electron mobility. I'm speculating now that they're using avalanche photodiodes.
They have a great product, unfortunately presented on a terrible website.
I didn't mean volunteer without pay. You must be aware that, for missions so unpleasant as to be sanity-threatening, the military only accepts volunteers. Same idea.
There is a 'shoot out' video on that page which compares themselves to other night vision technologies. Pretty impressive demo.
It's a numbers game. If you throw more spaghetti at some particular wall than anybody else or any other wall, then obviously that's where most of it will stick ...
It's mostly that humans are real easy to convince to hate and want to kill eachother, as long as the numbers are large enough you can forget they're individuals. So obviously the other dominant lifeforms on this planet (super-organisms, in this case multinational corporations) exploit this loophole for control and power.
Naturally, the closer to the 555nm green peak, and the more monochromatic your light source, the brighter it appears to be. This is a part of why night vision systems are green.
You measure a lumen by taking the area of your light source spectrogram in respect to the luminosity function.
I did this years ago with some manufacturers LED light output curves to reverse engineer electrical->photon efficiency vs cost from their data sheets. The main purpose was to figure out how close we were to LED lighting taking over.
I did that research back in 2012 and predicted 2015 as the point where LED was more efficient and cheaper than CFL but I was off by a year or so. Hilariously that paper got me a C- because it was only tangentially related to the teacher's pet subject and never saw the light of day.