Read speed limit signs using Cam

ThunderStick · 06-29-2009, 09:37 PM

Like the title says I am trying to gage interest in the ability for your carputer to read speed limit signs using an installed webcam or digital cam. I dont think it will be too hard to do this considering a good enough quality video can be taken. What this will do is scan the road side for a rectangular shape and a black border with black numbers. This part should be relatively easy to do since most signs are posted at the same hieght or about and are the same size and shape. Once a sign is discovered, it will freeze frame the video and determine the speed limit using OCR technology. Since the signs are black and white this should also be pretty easy.

Of course in theory it is easy but an actuallity it maybe pretty dificult recognizing a sign and freeze frame a good enough quality pic. But with out trying who can say for sure.

At work we use this same type of theory for checking for product quality deficiencies as they travel down a conveyor belt. Our system checks for product dimensions (by determining borders) and foriegn contaminents in the plastic parts by looking for color variations.

kev000 · 06-30-2009, 02:27 AM

Just out of curiosity, what would my carpc want to do once it knows the speed limit? I guess if used with something like the V1 and obdII/gps, if the carpc detects a cop in the area, and you are speeding, it will kindly alert you to slow down? This is about the only purpose I can think of it serving...

Crinos · 06-30-2009, 04:21 AM

I know for a fact that this works... Well vice verca actually... A fixed camera filming licensplates and convert them with OCR to understandable data for the software...
A friend of mine developed the tollroad system used in most of Norway, and this works on 98% of all passing cars.

Kev000:
If you are like me... Pass a sign and go "hum... did it say 60 or 80", it would be coold to have the frontend telling you the current speedlimit

Thunderstick:
I have thought about this for my own front end... But will not make the first versions.. Got other things to focus on first

ThunderStick · 06-30-2009, 09:03 AM

I was testing some OCR software last night and got about 75% success using speed limit sign images from google. I think with a little refining this maybe easier than I thought.

Crinos · 06-30-2009, 10:04 AM

Only one thing though... where YOU have speed signs that are sqare, white with black text.
Europe have a sircle with red line around, white background and black text. So if you thinkg about something for everyone here to use, you need to make it "euro friendly". Otherwise... Ignore us, and make the us only. hehe...

Though... For simplicity.. focus on on at the time

My friend used quite some time getting the accuracy up to 98%.
But, it's accurat up with cars passing in 160km/h

kev000 · 06-30-2009, 10:28 AM

In addition, you should make it so it at least works on Linux, and then worry about windows later...

Errr... was that supposed to be make it work on Linux and windows? Or maybe just mac?

If you need some help making it crossplatform, I'd be happy to help

. If you release the code under an open source license, I'll even include it in LinuxICE2.

kev000 · 06-30-2009, 10:31 AM

Quote: Originally Posted by Crinos

Kev000:
If you are like me... Pass a sign and go "hum... did it say 60 or 80", it would be coold to have the frontend telling you the current speedlimit

I'm pretty sure it either said 80 or 90. 60 would just be silly for this stretch of road :P

digital79 · 06-30-2009, 11:51 AM

FYI, I spoke once with a company that does geo-tagging of traffic signs, and they had some high quality cameras and plenty of processing power to do this. They were driving slow too. I think their equipment was around $30'000, and to get as close to 100% accuracy, they were driving 20-30 mph. Some of the recognition was done post-process, and sometimes manually.

Of course, your application is a bit different, but don't expect to read every speed sign you see. It's a very cool project, good luck.

bowser22 · 06-30-2009, 12:03 PM

maybe we can get some anpr on the go at the same time,,create a database of ghost and undercover cars

Crinos · 06-30-2009, 03:45 PM

Quote: Originally Posted by digital79

FYI, I spoke once with a company that does geo-tagging of traffic signs, and they had some high quality cameras and plenty of processing power to do this. They were driving slow too. I think their equipment was around $30'000, and to get as close to 100% accuracy, they were driving 20-30 mph. Some of the recognition was done post-process, and sometimes manually.

Of course, your application is a bit different, but don't expect to read every speed sign you see. It's a very cool project, good luck.

I'm quite posetive that I will be able to do this with my carpc and my own programming.

If you can get a clear image, there's no problem in reading the sign. A high quality webcam can capture 50 frames per second.
Going at 90km/h is equal to 25m/s -> equals 2 frames per meter.

Now... getting the system to respond to a speed sign BEFORE you get there, might demand quite fancy hardware, but if one can live with an "answer" a few meters behind the sign.... it's most doable from a carpc

Something like this would be good for cars that do not have speed warning. With this, the car could warn you if a know speed box is up ahead, and your speeding

(something I do 98% of the time).

digital79 · 06-30-2009, 04:02 PM

Quote: Originally Posted by Crinos

If you can get a clear image, there's no problem in reading the sign.

Yeah, getting a clear image is going to be a tricky part of this project. Perhaps you could use a point and shoot canon camera with image stabilization? Set ISO to the highest possible, disable flash, etc...

Crinos · 06-30-2009, 05:20 PM

Quote: Originally Posted by digital79

Yeah, getting a clear image is going to be a tricky part of this project. Perhaps you could use a point and shoot canon camera with image stabilization? Set ISO to the highest possible, disable flash, etc...

For what?

This is still doable from a better than average webcam. Atleast at daytime. Nighttimes can be harder though.

NB: High ISO grains the picture, and you do not want that for picture processing.... ISO 100 is perfect for daylight

Allthough... many amatouer SLR's don't go lower than 200 ISO.

digital79 · 06-30-2009, 05:27 PM

Quote: Originally Posted by Crinos

For what?

This is still doable from a better than average webcam. Atleast at daytime. Nighttimes can be harder though.

The amount of blur will be higher when traveling at higher speeds. I'm sure you are more tolerant to missing a sign telling you 40, when traveling at 50, rather when travelling at 80

I'd say high ISO point & shoot canon should be better for night time, than a web cam. In theory anyways...

ThunderStick · 06-30-2009, 10:12 PM

To answer the Euro sign question about round and red... SORRY NO PLANS FOR THAT. My car stays in the US, so "sorry chaps this bit may be limited to the bloats in America..."

As far as Blurr goes, this is going to be the tricky part.
Your camera will have to be pointed just slightly angled to the right or left. Of course the more you point your camera to the side the more "motion blurr" your gonna get.

My game plan for detecting the sign is to simply have a video montoring software monitor specific pixels in a boxed off area of the video. Will watch for black and white pixels in specific patterns. When it finds those pixels it will freeze the pic and send it to the OCR software. I have the OCR software working about 50% actually. Tested with speed limit sign images from GOOGLE I can get it to read Speed Limit allmost every time the trouble I am having is getting it to read the numbers. A lot of the time the signs have a bolt in between the two digits and that seems to through off the OCR. With a little work though, I think this will get resolved.

kev000 · 07-01-2009, 12:07 AM

and how about making it crossplatform?

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