Read speed limit signs using Cam

**digital79** · 06-30-2009, 04:02 PM

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

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

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.

**tripzero** · 07-01-2009, 12:07 AM

and how about making it crossplatform?

**Crinos** · 07-01-2009, 06:18 AM

If your camera is placed behind the inside mirror, and pointing fairly stright forward with a bit of zoom. The pictures would be much better, than captured from an angle.
Speed signs is allways in about the same height, so one can focuse on one sertaint area of the image, narrowing down the bit-stream.

I have no idea of how I would make this cross platform since the original code for the tollroad system is written in delphi and my system will be written in C#

**ThunderStick** · 07-01-2009, 10:06 AM

I dont think cross platform is important. It would be nice but mose CarPC owners are running Windows.

**mdawg** · 07-01-2009, 11:12 AM

I like the idea, there are lots of time when I'm in new placed I end up wondering if I am speeding because I'm not paying attention. Subscribed.

**Bugbyte** · 07-01-2009, 11:23 AM

This would be good way of recording the speed limits for certain stretches of roads. When combined with a set of GPS traces, it could add speed limit data.

In some distant future, it could record the speed of the car, compare it to the speed limit, and relay some kind of speed index (i.e. 80% of speed limit) to a server so others could see whether the route was congested. Eh, obviously it would simply report 100% if you were traveling faster than the limit!

In any case, it is a cool first step towards using a car PC for something different and unusual.

**tripzero** · 07-02-2009, 06:31 AM

Originally Posted by Crinos

I have no idea of how I would make this cross platform since the original code for the tollroad system is written in delphi and my system will be written in C#

That's funny, I'm writing an app in C# for Linux as we speak.

Thunderstick, what language is it written in? I mentioned before I wouldn't mind helping make it work on everything. If it's any .NET language, just don't hardcode any C:\ paths and make the video device configurable. Then it will work on Mac/Linux without any code changes.

Most people use Windows on their carpc because most software for carpc's are written for windows. It's the chicken and the egg all the way to the supermarket. The more apps like this that aren't frontend plugins that are written crossplatform the more freedom everyone will have choosing the platform that works best for them.

How many people in this forum would be running Linux if only their favorite Navigation App, XM plugin, XYZ app ran on Linux also? I know for a fact there's a lot. There's plenty of people who aren't afraid of the unknown and are willing to try something new if they see the benefit and value from doing so.

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