Militarizing your backyard with Python, Arduino, and computer vision.

http://pyvideo.org/video/674/militarizing-your-backyard-with-python-computer

by kscottz • 14 years ago

355 72 14 years ago

pyvideo.org

swordswinger12• 14 years ago

15:50 for the cannon in action.

AngrySkillzz• 14 years ago

Relevant XKCD: http://xkcd.com/382/

vibrunazo• 14 years ago

I'm impressed that he can get low false positives with such simple methods. That's great to know.

If he tried using line detection, vectorize it, then train the algorithm with the tagged shapes of squirrels. Would that be too slow to do in real time? Or could it work to reduce false positives?

SammoJ• 14 years ago

Adding complementary features such as edges (I'm guessing this is what you mean by lines) tends to improve the accuracy. It would also be possible to do this in real time.

I don't have time to watch the full video so I don't know what features he is currently using, but in object detection nowadays most people are using some variant of the SIFT descriptor. These are built not upon edges but on the image gradient per-pixel. The current 'hot' feature in terms of frequency of use is probably Histograms of Oriented Gradients (HOG) which do exactly what they say on the tin: Take a region of the image and count how many times a particular gradient direction occurs and the total magnitudes. Slightly more difficult to run in real-time but libraries exist.

kgrandis3• 14 years ago

I didn't show the false positive video. :P There were some additional features thrown in, but for presentational simplicity I went with some strong, easy ones to explain. I think one thing helped keep FPs low was some frame-based signal thresholding. So, I required a significant squirrel signal (over multiple frames) before it went hot. That prevented any small FP blip to trigger the gun.

SudarshanP• 14 years ago

One of the spectators in that video talks about http://info.ee.surrey.ac.uk/Personal/Z.Kalal/tld.html which was discussed on HN before and a nice demo of what computer vision can do...

jamesbowman• 14 years ago

As the person who wrote the OpenCV Python bindings, this makes me inordinately happy.

bicknergseng• 14 years ago

I imagine the team behind Kinect feels the same way when lightsaber-anything gets made.

Riesling• 14 years ago

As a person who used those bindings in a couple of projects (this includes tutoring the computer vision course at uni) I will use this opportunity to say thanks.

fgimenez• 14 years ago

I don't say this enough to people like you, so THANK YOU SO MUCH!

doctoboggan• 14 years ago

Awesome, I have been using the your work a lot recently. I do have one question though, is SIFT available in the python bindings? I have not been able to find it.

Thanks for contributing your time, it has made my life much easier.

apu• 14 years ago

For SIFT computation, I recommend VLFeat[1], which there are some python bindings for[2] (although I haven't tried them myself).

[1] http://www.vlfeat.org/

[2] http://www.janeriksolem.net/2011/06/another-python-interface...

draven• 14 years ago

A colleague of mine is developping a Cython (and OpenMP) based sift wrapper. It's available here: https://github.com/kif/imageAlignment

It's already used for alignment of X-ray images.

hugs• 14 years ago

Hey, thank you for that code! Your OpenCV bindings made more than one appearance at PyCon this year. I used it in my "Angry Birds playing robot". Thank you, thank you, thank you! http://pyvideo.org/video/683/building-a-robot-that-can-play-...

kgrandis3• 14 years ago

Thanks! You definitely made things much easier for me. I had also played around doing some raw ctypes work with OpenCV and now greatly appreciate your efforts.

rauljara2• 14 years ago

I think a fair number of homeowners would be willing to pay a lot of money for a version of this system they didn't have to program themselves. And had more firepower, of course.

nl• 14 years ago

I think a fair number of nation-states would be willing to pay a lot of money for a version of this system they didn't have to program themselves. And had more firepower, of course.

Estragon2• 14 years ago

I think a number of terrorists are going to be willing to figure out how to hook such a system up to a gun on a $300 RC quadrocopter. I hope it's a small number. It's going to be interesting.

rauljara2• 14 years ago

A low number of false positives with a water pistol is an impressive engineering feat. A low number of false positives with an actual gun is a disaster. The technology is still a long way off.

patrickk• 14 years ago

They already have them:

http://www.gizmag.com/korea-dodamm-super-aegis-autonomos-rob...

Confusion2• 14 years ago

I'm not sure. I've thought about building this kind of system from time to time, but I've never gotten around to it. I'd pay up to $75 for a simple version that keeps pigeons from my balcony. Nothing fancy required: it could fire at anything that moved. I would switch if off if I wanted to use the balcony myself. I wonder whether $75 would be enough to make this a viable product.

wmeredith• 14 years ago

I think you're on the right track here. This is bringing a laser pistol to a gun fight. You can keep a lot of pests away with a plastic owl attached to your roof acting as a scarecrow or with always on "dumb" ultrasonic devices. Both much cheaper and with far less moving parts.

arandomJohn• 14 years ago

I attended the talk. It was pretty cool, especially the OpenCV part. Frankly I think he needs to upgrade the armaments. Hook that bad boy up to the hose with a nozzle.

Frankly, if you wanted to, you could hook such a system up to an automated sprinkler control system and just turn on the water for whatever area the squirrels happen to be in at the moment. It would only have to be on for a few moments. Soon they'd think your yard is some sort of special hell, where water follows them wherever they go.

kayz• 14 years ago

I was there too :) It was such a fun talk, especially the part where in the end of the demo video, the squirrel stopped caring about the water cannon anymore, and decided to steal food while getting sprayed on. I wonder if there is a better way to deter them instead of bigger water cannons?

elviejo• 14 years ago

Well the arms race can begin... more potent water pistol. Then nerf dart gun... then golf balls gun... then gotcha gun... (at this point gets dangerous)

culturestate• 14 years ago

You'd have to keep the sprinkler system constantly pressurized, though. I've never seen one that can do that - they all take x seconds to really get going.

trebor3• 14 years ago

What about airsoft? You could mount a cheap, automatic, battery-powered unit and seriously sting those squirrels! I thought of using a similar system to protect the chickens I've got from the feral/neighborhood cats (I do have a fence... but that doesn't feel "complete").

woodall2• 14 years ago

We have chickens too, around 25 free range + a pony + a few ducks, and had issues with dogs and wild coyotes. I think harming the animal is a bit inhumane but I totally understand where you are coming from. Remember you are a guest in their space.

Here are some suggestions that have worked for our farm:

1. Pee around the coop. Enough said.

2. Get a puppy and train him. We have an aussie that does a great job, but there are other breeds that make even better farm dogs.

3. Train the chickens to go back into the barn when the sun goes down. This isn't very hard and most of the time they will do it themselves.

4. Motion sensor and/or electric fence on a timer.

5. Be aware; this is by far the hardest thing.

Our first year we lost 10 chickens. If that's not motivation enough to do something, I don't know what is but I would never hurt another animal for doing what they do naturally.

trebor3• 14 years ago

Our chickens aren't exactly free-range, but they have a large fenced-in area. The fence is electric, and the chickens do go in at night. But when a cat walks by and scares them, they have a tendency to get outside the fence and not know how. And outside the fence... some of the cats would be interested in getting them. And since a big siamese-like cat comes around that will hunt ground hogs, a chicken isn't such an intimidating target.

While I understand that cats are born predators, I can't afford to lose chickens. I wouldn't kill them because they do keep pests down and may belong to someone, but I do want to scare them away from the coop.

kgrandis3• 14 years ago

I thought about going that direction, but was concerned the birds might eat the pellets.

trebor3• 14 years ago

Yeah, my sister pointed that out to me. It's a fairly serious concern. (Coincidentally, that's probably where the term "bird brained" came from...)

trotsky• 14 years ago

Awesome talk, but I can't resist: Leave it to a software engineer to find a $250 solution to a $10 problem :) (http://www.wbcboulder.com/pole_mounted_baffles_sub.html)

TamDenholm• 14 years ago

Well sure, but its not really about that, its about the process, figuring out how to do this stuff and then doing it is extremely enjoyable and really cool, as is doing a talk for others who think the same thing.

MaxGabriel• 14 years ago

He has trees from which the squirrels can leap to the feeder

simcop2387• 14 years ago

I can tell you right now that those don't work at all. We've got a few on our feeders with NOTHING else around them and the squirrels still get on them. They only work if you have a single feeder/pole within about 10 feet of each other. Those little fsckers pull some ninja-esque moves jumping from metal pole to metal pole to get around them. It's entertaining to watch but it can get expensive since when they get up there they eat their fill which can sometimes be 1/6th to 1/5th of the feeder at a time.

HeyLaughingBoy• 14 years ago

they eat their fill

That's when you apply the $5 solution: a slingshot.

platz• 14 years ago

Innovation in technology comes from using technology in ways it wasn't intended, not necessarily what is the most efficient.

prawn• 14 years ago

Reminded me a bit of this old project from someone trying to stop non-cats or their cat carrying a dead animal from entering a cat door:

http://www.quantumpicture.com/Flo_Control/Flo_Control_1/flo_...

javajosh• 14 years ago

Seems like you'd be better off cutting off the approaches to the feeder. But the project is super cool. For more power, I'd use a power washer. :)

polyfractal• 14 years ago

Squirrels are notoriously ingenious at raiding feeders. They are really good at defeating feeders that are specifically designed to be "anti-squirrel" too.

ams6110• 14 years ago

A real python would probably take care of the squirrels even better.

8ig8• 14 years ago

The presenter's personal site: http://kurtgrandis.com/blog/

liquidcool• 14 years ago

I wonder if something like the Blender Defender (http://www.plasma2002.com/blenderdefender) would be more effective than the water. A strobe light and/or a rattle to frighten it off. Ultrasonic would be good as well if there was decent evidence it worked.

Ecio78• 14 years ago

My bro has a problem with a mole digging all the backyard, any idea for that problem? maybe a flying drone that drops bombs on its head ? :)

mogui• 14 years ago

neat and awesome talk

Militarizing your backyard with Python, Arduino, and computer vision.

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