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Comment by blin17 | Hacker News Reader

I hear of a lot of startups working on image detection and sound detection, but I'm wondering why there isn't anything done for scent detection. Maybe A2D for scent doesn't really exist yet, but it would limit the need for drug sniffing dogs

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> I'm wondering why there isn't anything done for scent detection ... it would limit the need for drug sniffing dogs

If police departments believe that they get the resources they want based on the Clever Hans Effect, what would be their incentive to use a more accurate mechanism for sniffing out drugs?

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3078300/

http://articles.chicagotribune.com/2011-01-06/news/ct-met-ca...

https://en.wikipedia.org/wiki/John_Preston_(dog_handler)

I did some work during my PhD on recognizing scenes from electronic-nose data. The problem is more on the hardware side of things than the algorithm side of things. Today's electronic noses are still pretty large devices in which a sample needs to be placed within the device. Unless the state-of-the-art has advanced significantly in the past 3 years, none of them are like wielding an artificial nose on a stick that you can just wave around sniffing things.

Can confirm.

I was "digitally sniffed" for explosives once at an airport in Florida about 3 years ago.

They took a piece of what looked like tissue (probably an odorless control) and rubbed it inside my backpack.

They then placed that "tissue" into a very large machine (half the size of the man performing the procedure) which I assume smelled it for explosives.

After standing there for about 30 seconds staring at the machine, I was told I was free to proceed into the secure waiting area.

Those are things similar to a mass spectrograms. The tissue picks up particles, and is then analyzed by the machine to create a mass spectrogram of the napkin. If it contains masses similar to explosive powder residues, then you're in trouble.

Olfaction is really amazing. (Even the crappy human version, to say nothing of e.g. canines.) We can build cameras that see better than eyes, microphones that hear better than ears, but there is no technology that comes close to matching a nose. Sure there are some special-purpose sensors that measure the precise concentrations of particular gases, but nothing so general as a what's found in all sorts of different animals. It's not even clear how to quantify smell, for that matter.

If they can accurately smell drugs they lose probable cause to search cars and confiscate cash.

They are incentivized to have false positives.

https://en.wikipedia.org/wiki/Electronic_nose

Electronic noses in specialized niche use cases is past startup phase and well into industrial implementation.

However, the nose of a trained dog exceeds electronic capabilities.

In fact, an electronic nose that good might be equivalent to a Star Trek tricorder.

https://en.wikipedia.org/wiki/Detection_dog

http://mythbustersresults.com/episode74

This kind of tech has been around for decades in the CBRN community. The initial gotchas would be lack of effectiveness with the commonly small quantities of substances in the user end of the market, and the high cost of equipment. Also the common use of radioisotopes for the detection devices that require NRC compliance headaches.

http://www.nap.edu/read/11431/chapter/6#27 https://www.ncjrs.gov/pdffiles1/nij/184450.pdf http://www.armedforces.co.uk/releases/raq433946e83fcdd#.VqBM...

I too have wondered this. It seems like it would be relatively simple to create a device that can detect drugs more accurately than a dog. The only problem might be that creating such a device might cost significantly more than training a dog.

>It seems like it would be relatively simple to create a device that can detect drugs more accurately than a dog.

It could be simple but tied up in patents I suppose. I have a feeling if it was even remotely simple it would be prevalent in airports though.

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