BlackOps Plastics (Opaque to the eye, transparent for cameras) | Hacker News Reader

BlackOps Plastics (Opaque to the eye, transparent for cameras)

qwonn.com

101 pointsmoe24 comments

That sure looks like magic. Cool!

It feels as if some sleight of hand is hiding in the way they're explaining it, that they've developed a "material that black & white cameras can see through, BUT THE HUMAN EYE CANNOT". The way I see it (heh), the human idea can't "see through" any material, because seeing is not an active process like that makes it sound.

Some materials block radiation from reaching our eyes, while some do not. Those that don't, appear transparent or translucent.

So, I would assume that this plastic blocks wavelengths that are visible to us, but that b&w video cameras have a slightly wider range of wavelengths where they are sensitive, and the material isn't blocking those.

So now it will become routine for counter-surveillance folks to smash all black plastic objects when sweeping a room? :)

Or simply use a black and white camera when checking a room, to see if any black plastic objects are actually hiding something.

My guess is that it is just a plastic that is IR-transparent and visible-opaque, viewed by a camera with no IR filter. Actually fairly common - coke cola is IR-transparent. Not sure you can get an image through it, but I wouldn't be surprised.

Most black plastics become transparent fairly quickly in the near-IR, it's something the dye designers aim for since it reduces the heat load into the material and makes it last longer.

Doing this with a regular (IR filter removed) BW camera and a polythene garbage bag is a standard science-fair demo.

As you get further into the infrared it becomes annoying. lots of things you think of as black, like black anodize and black electrical tape are transparent - so you get reflections and light leaks from things you would never think of.

Yup, you can see through Coke by opening up a cheap webcam and removing the IR filter. You can even make an IR-only camera by replacing the filter with a piece of exposed film, which is black in the visible spectrum and but lets IR light through. http://www.hoagieshouse.com/IR/

Makes sense, since they also took images where you can't see the interior.

I did my senior design project on an infrared related area. Things look really weird in the infrared.

http://imgur.com/SLGvT,y79tC First image - can you guess which one is diet coke, and which one is water? Second image - I was shining a 940 nm IR LED through my hand, you can see veins.

I can make this more interesting!

So webcams generally always respond to IR light. If you look at the front of your remote with our camera phone and press a button, you will see a bluish whitish light. Well, that seems a little weird at first. The light that's coming out of the LED should be closest to red... Well, when CMOS camera companies make their cameras, they heavily rely on the blocking abilities of the IR filter. They want to get amazing signal to noise ratios for the visible spectrum, and the combination of materials that does this is also absorb IR light as well. They can just use a coverall filter to get rid of the infrared light.

Here's the spectral response for the D200 - http://www.maxmax.com/images/Cameras/Technical/NikonD200_Spe...

i want to know...which one was the coke? i think it was the one on the right?

You're correct! If you look closely, you can see a couple bubbles near the top of the right one.

yes :) that's what I thought! Thanks!

This type of plastic is used to shield LEDs in many infrared remote controls (TV, stereo, etc).

We used a variant of it to make the entire "puck" of the Dropcam (http://www.dropcam.com) so that you wouldn't have to see the ugly IR emitters we use for night vision.

Interesting. I've been looking into dropcam. How secure are wifi cameras like this? How easy it for someone to hack into them and be able to view a live feed of my house? Is there a way to secure them better than just having a strong wifi password? Encryption? What about the server that the feed passes through, does it actually pass through a dropcam server or can I connect from my cell phone directly to my home network to obtain the feed?

Cool! Here's the lowdown on security: Dropcams encrypt all communications with TLS and use client certs + server certs, so they're resistant to sniffing and man-in-the-middle attacks even on open Wi-Fi networks.

Video does pass through our servers for NAT traversal, automated analysis (e.g. for motion/audio event detection), conversion, and (optional) storage. Local streaming when on the same network is "in work" as an optimization. Dropcam employees (including me, the CEO) are restricted from viewing your video by both technical and policy-based measures.

It's likely safer than storing video yourself. A burglar can steal any locally-stored video, and security bugs are even more likely to occur on your home network / devices than with a Dropcam since our software is continuously kept up-to-date (both server-side and OTA updates to cameras).

It's definitely safer than most other IP cameras which encourage you to use dyndns + open a port on your router. With those systems, don't forget to change the default password like 95% of people do, and also hope like hell that they don't have remote scripting vulnerabilities on their 2-year old firmware.

At Dropcam, we are incentivized to make sure you are the only one who can view your video, since you are our customer and we provide a service (not just a one-time sale). The only time we let others view your video is if you explicitly choose to share it.

Hope this helps, and thanks for considering Dropcam!

Fun fact: if you have dark eyes, taking photographs of yourself in near-infrared will make your iris' appear light, which is good if you're going for that trendy vampire look. I'm not really impressed by the technology behind this - IR pass plastics have been around for ages (the black plastic window on the front of your TV remote is an example).

But as for these guys...

"We have developed a technology to create covert concealment devices out of a material that black & white cameras can see through, BUT THE HUMAN EYE CANNOT!"

I may be wrong, but it seems to me that what they "developed" was a relationship with an injection molding company, whom they asked to use a slightly different, but still common plastic.

The whole AppleTV body is molded in a similar material.

I could be wrong, but this seems like they are using an IR camera, then inverting the images once they are taken.

If they had a specific type of plastic, it is unlikely they would need to produce the multitude of objects they did. Why on earth would they bother with some of those?

If it was as simple as that, couldn't they just process the live IR feed through a negative/inversion filter to achieve what they are doing?

No. All cameras have a IR filter over the sensor. You would need to remove that first which specialists on the web can do.

This is a very interesting product but the wording of the intro paragraph seems odd to me.

"We have developed a technology to create covert concealment devices out of a material that black & white cameras can see through."

I may be picking semantics here but I'm unclear... have they developed the plastic itself, or developed covert camera containers out of another manufacturer's material? The containers are a great idea in their field but actually having engineered the plastic itself would be even more impressive.

It could be a polarizing material that polarization changes angle across the surface, so that opposite sides are at 90 degrees difference. You can see from the inside with slightly changed color, but you can't see through two of the opposite sides of the glass.

I want the other way around so I can put a piece over my license plate.

Just wait until somebody starts selling clothes made out of this material without telling people what they're buying...

Goodrich ISR sensor equipment has been able to do this for a while regardless of the type of plastic for the purpose of quality control in product containers:

http://www.sensorsinc.com/image_powderswirenlarge.html ... "While a visible camera cannot see through plastics, these same plastics are transparent with the short wave infrared. Goodrich ISR-P cameras can see through plastic to detect the fill level of a product. This capability is extremely helpful in quality control and process control applications."

Somebody make a teddy bear out of this material and put it on a mantle a la The Parent Trap. It'll look like Metal Mario from Mario N64 and will keep your house totally safe. Bonus points if you put a red headband on it or anything else to make it look like a ninja

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