21 ms·
Spy camera detection using smartphone time-of-flight sensors
- jeffbee 5y agoI'm having a hard time seeing how the obsolete and not exactly tiny OV2640 was crammed into that electrical plug. The integrated module is a 10mm cube with a 1/4" lens and to be useful it needs a power supply and either a storage controller or wireless network interface.
- frizensami 5y agoWe just used the OV2640 module itself (https://www.aliexpress.com/i/4000036275403.html https://www.aliexpress.com/i/4000036275403.html) which is pretty small. While we didn't actually include a little battery and perhaps something like an ESP-32 to control it, I'm pretty sure those could fit inside the plug if hollowed out.
- hyperstar 5y agoWhat are the best ways of doing this without a smartphone?
- frizensami 5y agoThe free option: use your smartphone's flashlight and try to spot unnaturally bright / colored reflection. If you want to spend some money and don't mind carrying an extra device: probably any of the "hidden camera detectors" on the market will be at least somewhat useful. K18, CC308+, etc. We're trying with our work to get better or at least equivalent results without having to use external devices.
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- est 5y agoPut a very bright light source next to the spot you don't want to be caught in a camera. The viewer would only see a ball of light.
- frizensami 5y agoI don't think this works, mainly because an extremely bright external source of 850 nm light looks incredibly suspicious through the sensor (as we expect the ToF sensor to be the only light source). We could add that check in explicitly.
- randomswede 5y agoI think the bright light is intended as a countermeasure to the hidden camera, not as a countermeasure to finding the hidden camera. Basically, to keep position X unobservable through the hidden camera, ensure that there is an overwhelming source of photons between position X and the hidden camera. Since we don't know where the hidden camera is, the best we cam do is to assume that the immediate vicinity of the bright light will accomplish this.
- frizensami 5y agoOh, I must have misunderstand, since the root comment was talking about detection methods. But yes, jamming is a good option, and there have been papers to make areas "unrecordable". I don't have my citation manager on hand now, but I think it was an early ACM Sensys / Mobisys research work.
- SubiculumCode 5y agoLAPD is not the Los Angeles Police Department, despite what we all were thinking.
- micahcc 5y agoOk I'm not crazy
- abfan1127 5y agowhat is it?
- throw_away 5y ago> To answer this question, we propose LAPD (Laser- Assisted Photography Detection)
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- elric 5y agoSo, could this be used to find better hiding spots for hidden cameras?
- DennisAleynikov 5y agoabsolutely, at least against this method of detection
- frizensami 5y agoYeah, that's fair. If someone really wanted to do this though, they could also just use existing products like this one: https://www.amazon.com/Worldoor-Multi-Detector-Full-Range-All-Round-Detector/dp/B00W32PLYS https://www.amazon.com/Worldoor-Multi-Detector-Full-Range-Al....
- dclowd9901 5y agoMaybe, but realistically, since the sensor uses the properties of a camera lens to detect the camera itself, I would have to bet there is little that could actually be done to obscure the hidden camera and also still get a usable image from it. This is a pretty brilliant detection method.
- nybble41 5y agoIt might be easier to design the room to create false positives and undermine trust in the detectors. Assuming you have that kind of influence, anyway. That's not an option if you're just trying to plant a camera in an existing room. I assume minimizing the aperture would be a fairly reliable way to avoid detection. A pinhole camera would be hard to find by any optical technique, though the video quality would suffer. Perhaps one could project through a pinhole onto a screen and record the projection, so the sensor is angled away from the room?
- frizensami 5y agoThat's an interesting idea: trying to create so many false positives that the user gives up. We're already removing around 100+ false positives per frame at the moment in difficult cases, so perhaps it's possible to overwhelm the filters with very maliciously designed environments. I think the easier way would be to hide the cameras in much harder-to-reach places so that it's inconvenient for the user to get their smartphone near. This might reduce the kind of videos that can be taken, but maybe an attacker will find that a reasonable tradeoff.
- SubiculumCode 5y agoI was really hoping that they had an app I could install, as they implemented LAPD on Android.
- rbanffy 5y agoYou'll still need the laser emitter. Here I would hope the emitter can be operated in a high-power small-target mode to also obliterate the detected cameras. Extra points if it can do so autonomously - I leave it over the bed, go out for dinner, and come back to a room without any cameras.
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- frizensami 5y agoHey! Author of the work here. We just finished presenting this at a conference yesterday, so we're working on open-sourcing the code now with some feedback from the community. It's got some warts because of API limitations (no way to automatically align color and ToF cameras, so we're manually doing that).
- SubiculumCode 5y agoCool work. It would be great for scanning hotel rooms.
- frizensami 5y agoThank you!
- micahcc 5y agoIt took me a full minute to realize this wasn't the Los Angeles Police Department's R&D division
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- jaywalk 5y agoYou have to go to the second page of the full PDF to even see what LAPD stands for, which is Laser-Assisted Photography Detection. They need to be more mindful of this, especially when they made up the acronym themselves.
- intrasight 5y agoCool tech. Too bad about the paper title. One should never use a novel acronym in an academic title IMHO.
- w0mbat 5y agoLAPD is worse than novel, it is already used in another context where it is very well known. Most people will already know this, but LAPD = Los Angeles Police Department, often featured in TV shows, films and the news.
- elzbardico 5y agoThe authors are from Singapore. The association is not that direct for non-americans. Actually, I only noticed it after several people mentioned it here.
- ska 5y ago> Most people will already know this, but LAPD s/most people/most americans/ plus some non americans of course, but it's not a global association by any means.
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- PeterHolzwarth 5y ago95.75 percent of the planet is not American, if you are partially referring to the acronym of the police department.
- frizensami 5y agoHey! Sriram here, author of this work. I'd be glad to answer any questions. There's also a short talk I gave about this here (https://www.youtube.com/watch?v=t4Txdhlji4k https://www.youtube.com/watch?v=t4Txdhlji4k) if that's helpful!
- starwind 5y agoDo you have any plans release this as an app I could install on my phone?
- frizensami 5y agoYes, we do! There are a couple of user-facing annoyances at the moment, one of which I mentioned in another comment (hacks to align the color and ToF images). Hopefully these API limitations are removed soon, or we find better workarounds.
- Iolaum 5y agoAwesome, if there's a waiting list or a website that we can join or follow to be notified of a release please share.
- frizensami 5y agoSadly no project-specific page yet, but I'll definitely update on my page at https://sriramsami.com/research/ https://sriramsami.com/research/ (I think there's an RSS feed?) when it's active.
- specto 5y agohttps://sriramsami.com/feed.xml https://sriramsami.com/feed.xml
- iamwil 5y agoIt's easy to set up a mailing list. Just sign up for mailchimp, or any one of the many newsletter products like substack or tinyletters, just to collect the email addresses. Not many people regularly read RSS anymore, sadly.
- anthomtb 5y agoThe acronym should be removed from the HN title. LAPD does nothing but sow confusion when used as the first word here.
- frizensami 5y agoAuthor here, sorry, I didn't post this (but it is the paper's title). Hopefully it gets corrected.
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- jcun4128 5y ago> system that leverages the time-of-flight (ToF) sensor on commodity smartphones I think only the high end iPhones/iPad have these type of cameras right now right? I'd also be curious about the exact angle you have to hit to get a reflection Probably wouldn't work but bright flash in a room?
- semi-extrinsic 5y agoMy Huawei P30 Pro from 2019 has a ToF sensor, so I don't think it's very uncommon?
- frizensami 5y agoYep, there are a pretty decent number of smartphones with it, and I think the trend is moving in the right direction (iPhone 12 Pro had it and Apple included it in the iPhone 13 Pro too).
- jcun4128 5y agoYeah I guess my phone is not in that tier... it looks to be marked up 2x from GSMArena's prices... but $150 vs. $350 pricing. Also the Moto G Stylus (my phone) is from 2020
- frizensami 5y agoGreat question about the angle actually. There's previous work by an applied physics group [1] that shows the detectable field-of-view from the camera is about 20 degrees. Our experiments also confirm that. We also think using the smartphone flashlight (if that's what you mean) is the best way forward. That's already very helpful (and recommended) for humans to find hidden cameras, and it should be a useful extra modality for our work too. [1] https://ieeexplore.ieee.org/document/8790792 https://ieeexplore.ieee.org/document/8790792
- jcun4128 5y agoYou don't have to answer but, I'm assuming by the phone's API you can steer the beam/have an exact precision known of the minimum angle you can sample? That's pretty cool tech to work with.
- fortran77 5y agoI was working on a project like this and we relied on the fact that the IR filter on most cameras was a retro reflector. Remove the IR filter and the camera will be harder to find. I think the technique here also depends on the IR filter’s characteristics.
- frizensami 5y agoThat's a good point. I'm not sure how the removal of the IR filter will affect this work. I mentioned some prior work from the physics side [1] in another comment that explores the reflection characteristics in more detail. I don't think they explored the IR filter contribution as well, so this could be an interesting direction. [1] https://ieeexplore.ieee.org/document/8790792 https://ieeexplore.ieee.org/document/8790792
- sturgl 5y agoIR cut filters used in smartphone-style cameras are typically reflective. Installing an absorptive IR cut filter on top of the lens would decrease the amount of reflected light, and might hinder your approach. Those are pretty cheap to buy, so you could try it out pretty easily.
- fortran77 5y agoThe key is they're _retroreflective_. From this paper: > Specifically, the hiddencamera embedded in the object reflects the incoming laser pulses at a higher intensity than its surroundings due to an effect called lens-sensor retro-reflection. This occurs when almost all light energy impacting an object is reflected directly back to the source (see Section 2.2). These unexpectedly high-intensity reflections from hidden cameras cause certain regions of the ToF sensor to be “saturated” and appear as black pixels. LAPD processes these saturated areas to automatically identify the hidden camera and its location and displays it on the user’s smartphone screen.
- sturgl 5y agoNevertheless, if you block all the ~850nm IR light from reaching the lens, then there cannot be any retro reflection at this wavelength, meaning the ToF cannot see anything.
- errcorrectcode 5y agoMolka is/was a problem in Korea. I wonder how it compares to SpyFinder Pro which seems like it's 95%+. https://www.kickstarter.com/projects/spyassociates/spyfinder-pro-hidden-camera-detector-spying-preven https://www.kickstarter.com/projects/spyassociates/spyfinder...
- frizensami 5y agoGood question. We evaluated the "K18" hidden camera detector, and not the SpyFinder, but they use an identical principle.
- schleck8 5y agoWhile it's especially bad of a situation in South Korea, it has become a serious issue globally. > The same poll found that one in 10 guests (11%) had found hidden cameras in an Airbnb rental. https://www.forbes.com/sites/suzannerowankelleher/2020/01/27/why-you-should-start-screening-for-hidden-spy-cameras-when-you-travel/?sh=24a170ae5afd https://www.forbes.com/sites/suzannerowankelleher/2020/01/27...
- errcorrectcode 5y agoThat number seems absurd and speculative to fit a FUD narrative.
- max47 5y agothat kickstarter campaign is borderline a scam. They have an msrp of 400$ for a Chinese gadget you can by for <10$ online. And no, their LEDs are not special and you can source better ones from digikey for less than 1$.
- errcorrectcode 5y agoIt's not a "scam" if people buy it and it works. There is the cost to design such a thing. It's not free. The unit price was high. The rest are knock-offs who didn't have to pay for R&D. Then you can make and sell your very own one using their effort.
- woeirua 5y agoI wonder how hard it would be to engineer a material that you can put on top of the hidden camera lens that would greatly diffuse the specific frequency range of light that these ToF sensors use while permitting mostly visible light through? If so, it might be possible to defeat this approach relatively easily. Looking at what the DL filter is doing, I wonder how well this really generalizes. It seems that many of those examples are virtually indistinguishable to a human (hence the high false positive rate for the naked eye experiments).
- jcun4128 5y agoBring a 360 degree projector, up the ante
- frizensami 5y agow.r.t the material, it seems to be possible, since ToF sensors operate in a narrow 850 nm band. However, I don't know if a coating can be made that also doesn't overlap with the visible light range since 850 nm is somewhat close to red light, or whether that would be cheap if so (given that the hidden cameras themselves are only $1 at the moment). I also have similar reservations about the DL approach in general. What makes me more confident is that we trained on a relatively small number of objects (~10) and tested on a totally different set of 30 objects. We're also using very small regions-of-interest as inputs (5x5), so there's little to no overfitting on the environment or objects themselves.
- ww520 5y agoDoes the app take pictures to find the lens? Or videos?
- frizensami 5y agoIt's analyzing the camera feed in real time, so more like a video.
- ww520 5y agoGood to know. Yes, continuous video feed is easier to spot a light source. Can do differential analysis.
- coretx 5y agoDid the Rubidium price go up already ? ;-)
- raldi 5y ago"Specifically, the hidden camera [...] reflects the incoming laser pulses at a higher intensity than its surroundings due to an effect called lens-sensor retro-reflection. This occurs when almost all light energy impacting an object is reflected directly back to the source"
- polishdude20 5y agoGiven this, can you just hold up a flashlight right next to your head and look around the room for bright spots?
- frizensami 5y agoThis is actually one of the recommended methods if you have no other options. It's not particularly good otherwise because of the limited visibility cone of the hidden camera reflections. From experience, the flashlight often tends to occlude the reflections you want to see, or the user isn't in the right place to see the reflections (near the flashlight).
- gpt5 5y agoThat's exactly how detection tools work today. Here is a random one: https://www.lexuma.com/products/lexuma-xscan-portable-hidden-camera-detector https://www.lexuma.com/products/lexuma-xscan-portable-hidden...
- xipho 5y agoLikely. Headlamps are well known tools for collecting spiders at night, when positioned just right they will reflect off the spider's eyes as you move your head around. It's an amazing thing to see spiders everywhere.
- lapetitejort 5y agoFor peace of mind that sounds like the worst tool to use.
- 5y ago
- z3t4 5y agoIf the spy camera has infrared leds then you can detect those by removing the infrared filter from a camera, can be done on some smartphone cameras programmatically I think.
- Scoundreller 5y agoIn a dark room, you can point an old-style remote control at an iPhone camera and see button presses light up the IR transmitter. I do this to test their batteries :) But older Cell-phones (flip phones) with CMOS sensors used to be really good at this as they wouldn’t filter much IR in order to work better in low-light conditions.
- injidup 5y agoI know a woman who discovered a hidden camera in the female toilet at work disguised as some kind of utility hook on the door. Cheap to buy on amazon!! The SD card inside had pictures of the company owner's desk but not an actual picture of him. The police declined to prosecute because of lack of evidence.
- xanaxagoras 5y agoGross.
- stronglikedan 5y ago> The police declined to prosecute because of lack of evidence. Thank goodness! Imagine being convicted of a crime because some perv took some pictures of your personal stuff in an attempt to frame you.
- spoonjim 5y agoProsecute and convict are different. You should at least pull his credit card transactions and see if he recently bought it.
- deleted 5y ago[deleted]
- jjcon 5y agoThat would still be circumstantial wouldn't it?
- HWR_14 5y agoI mean, if you showed him buying the same model from Amazon and it had pictures from him testing it in his office, that's probably enough to convict.
- moron4hire 5y agoMost evidence is. "Circumstantial" doesn't automatically make the evidence useless.
- cf100clunk 5y ago"Tiny hidden spy cameras concealed in sensitive locations including hotels and bathrooms are becoming a significant threat worldwide." I think motel room tenting and indoor foil-wearing might seem to be more justifiable, less paranoiac. Who knew?
- qwertox 5y agoHere's a demo video [0] of the app. It is embedded in the author's website [1] [0] https://www.youtube.com/watch?v=AFjGQNaqmXA https://www.youtube.com/watch?v=AFjGQNaqmXA [1] https://sriramsami.com/research/ https://sriramsami.com/research/
- aaronax 5y agoThis reminds me in a way of the yacht with a system that detects cameras taking a picture of the yacht and sends a beam towards the camera to wash out the image. https://petapixel.com/2012/10/28/worlds-largest-private-yacht-features-a-laser-based-anti-photo-shield/ https://petapixel.com/2012/10/28/worlds-largest-private-yach...
- frizensami 5y agoPretty interesting idea. In fact, there are a number of military-related systems to spot sniper scopes (generally optics) with lasers, which I expect is similar to what they used here.
- iseanstevens 5y agoClever! Thanks :)
- samstave 5y agoIf there was literally ANY metric I would want in a HUD; 'How many cameras are viewing me now, and where are they' has got to be the top of the list...
- emptyparadise 5y agoPut all their fields of view on a minimap.
- benbojangles 5y agosimilar technology exists on ebay for under $5, you plug it into the phone's usb port and it emits ir led lighting and back into a lens
- chris_wot 5y agoCan you supply a link to one of these devices?
- victoraaa 5y agofdsd
- simonebrunozzi 5y agoI would be curious to know what would be the best method/tool to detect hidden cameras in places you visit (e.g. hotels, AirBnBs). I looked for devices on Amazon.com and found nothing that seems to be really good at detection.
- HackOfAllTrades 5y agoA stand-alone Single-Point LIDAR might be used to remove the high-end phone requirement. Should interface to a phone USB port with a simple UART/I2C-USB adapter. Search Amazon.com for LIDAR finds 'Lidar Range Finder Sensor Module TF-Luna, Single-Point Micro Ranging Module 0.2 to 8m Compatible with Pixhawk, Arduino and Rasppbarry Pi with UART / I2C Communication Interface' $25. And 'MakerFocus TFmini-s Micro Lidar Module 0.1-12M Lidar Range Finder Sensor Obstacle Avoidance Sensor Tiny Module 1000Hz Single Point UART I2C IO Compatible with Pixhawk Ar duino and Raspberry Pi' $39. The 2nd one is waterproof.
- HackOfAllTrades 5y agoAlso on Amazon 'Worldoor CC308+ Multi-Detector Full-Range All-Round Detector For Hidden Camera / IP Lens/ GMS BUG / RF Signal Detector Finder , CC308 + detector hidden mini camera/IP camera/general manager/radio frequency signal detector instrument' <$20. And several similar hidden camera detectors. I have no idea how well/badly this sort of device works.
- chris_wot 5y agoWhat I would like to know is - how do you detect who is using an IR blaster?
- djmips 5y agoMy old smart phone would easily show IR light. I suppose newer models might have IR filters.
- aaron695 5y agoIt's interesting with these wrap head lamps, which have 40 COB(Chip on Board) LEDs, is you see spiders everywhere at night. And other large animal eyes with a Tapetum lucidum look 'strange', not like normal led reflections. It's a bit unnerving/cool that you'll see 10 pairs of eyes looking back from the lawn you might have just been lying on. https://www.amazon.com/Headlight-Rechargeable-210%C2%B0Illumination-Headlights-Lightweight/dp/B09579W64H/ https://www.amazon.com/Headlight-Rechargeable-210%C2%B0Illum... I'd be looking at something like that, at least as a first run over the room. But perhaps to augment. It allows you to see spider eyes at 5+ meters.
- ngneer 5y agoCould someone please help explain the threat? Are people being blackmailed with footage obtained of them? Is this occurring en masse?
- Enginerrrd 5y agoEver stay in an airbnb?
- ngneer 5y agoOf course, frequently. I must still be missing something. I have had zero extortion requests. My footage might be captured for private consumption by some perv, but where is the harm to me?
- mensetmanusman 5y agoExtortion is generally geared towards women. Violence towards women like this is a general negative externality/tax on society because everyone interacts with women.
- ngneer 5y agoI am inclined to agree, and you are correct if you assume that I am male. But I would prefer to see the data. Without it, the first sentence of the abstract is unsubstantiated. "Tiny hidden spy cameras concealed in sensitive locations including hotels and bathrooms are becoming a significant threat worldwide." The paper cites no evidence for "significant threat worldwide". Academic fancy?
- trickstra 5y agoWould you argue that voyeurism should stop being a crime then?
- ngneer 5y agoThat is a good question, and thanks for helping me to test the limits of my argument. I would say that voyeurism, like all crime, can be expected to follow a spatiotemporal probability cloud. Society does not accept folks peering into your home and as an individual you have recourse. I think it is fuzzier as soon as you step out into public. I would definitely consider an airbnb or most other spaces that are outside my control to be public spaces. But the question of voyeurism is sort of distinct from my main question, which is how big is the risk? Do we have data on how many people are hurt by this issue?
- ridaj 5y agoCan you overwhelm this detector by hiding the camera in another reflective material (eg wrinkled metal or shards of glass wall decor)
- djmips 5y agoYes.
- frizensami 5y agoI'm not sure that it's a conclusive yes here. We have a procedure to remove the effects of background reflection saturation by constantly analysing the maximum reflection size. So if there's a large reflection in the scene, we walk the user back til we have all reflections at the same size or smaller than the the larger expected hidden camera reflection. This works fairly well. However, if the camera reflection is always within a larger reflection for all possible distances and angles, then I doubt this will work.
- super_tycoon 5y agoPlayed around with this idea using the ToF sensor on my galaxy note 10+ and an app called 'ToF Viewer'[1] https://imgur.com/a/XcEMxcZ https://imgur.com/a/XcEMxcZ Camera array of a thinkpad T480 with windows hello (ir camera) and a hazard light/strobe (sourced... locally) [1] https://play.google.com/store/apps/details?id=com.lvonasek.tofviewer&hl=en_US&gl=US https://play.google.com/store/apps/details?id=com.lvonasek.t...
- frizensami 5y agoFunnily enough this is exactly how we started the project, just with a different Thinkpad model. Separately, Lubos, the creator of ToF Viewer, is very helpful to the ToF community and constantly answers any questions about APIs or sample code. I'd recommend talking to him if anyone wants to get started with ToF-based applications.
- elwell 5y agoThe expansion/collapsing of the header on that page seems to get in the way when scrolling up.
- milleramp 5y agoIt hard to tell if these modules contained IR interference filters, some of the part numbers are only for sensors not modules. If they have interference filters I could see that there would be a strong IR reflection. It would be interesting to see the results with a absorptive filter, although I am guessing real spy cameras have no filter at all. Improve the sensitivity vs making a pretty picture.
- latexr 5y agoThe site is unusable if you have cookies disabled. It does not let you read the content of any page.
- frizensami 5y agoPerhaps you could try this direct PDF link at https://dl.acm.org/doi/pdf/10.1145/3485730.3485941 https://dl.acm.org/doi/pdf/10.1145/3485730.3485941. Hopefully that works.
- latexr 5y agoSame issue, but thank you for trying for an alternative. I’ll skip this one; it may be wise be wary of a website so adamant about cookies that they refuse to show any content when they don’t get them.
- egberts1 5y agoLenless camera, the latest next research rage?
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