Recognize Auto-Signs
nidzix from Serbia and Montenegro  [2 posts]
9 years
I'm completely new in this sphere. Can anyone give me an idea about making a program that can be able to RECOGNIZE AUTO-SIGNS (the signs that show the max allowed speed on the roads). My camera is on the right rear-wiew-mirror on my car.

Yes, I tried to do smth. without anyones help, but I stopped when I should recognize all circles at the right side of the screen, then my program recognize satelite antenna,etc.

Any kind of help, for me, will be enormous.  THANKS!
John Christian from Norway  [25 posts] 9 years
It would help if you could post some sample pictures to see what we are working with here. The immediate thought is that you would have to try to make the camera stable enough so the image isnt blurred. Other than that you would probably have to look more at the color of the signs. For example the speed signs here in Norway have a red round circle with the speed number inside. I would then try to filter for this red color first before attempting to find the circle of the sign. Also you could try to filter out all around the detected circles and work on each circle with some processing to identify more about them. For example our speed signs would be detected as two circles since the red ring is somethat thick. Other than that you could look at average color of the circle to see if it its a blue sign or something else. Furthermore you can use the shape detector to identify the image inside the sign. Naturally this is simpler if there is only one sign in the picture.

Also, you might think about working with as high resolution as possible since signs will probably be a bit small unless your camera have "zoomed" in on an area that usually contains the signs.
nidzix from Serbia and Montenegro  [2 posts] 9 years
Ok. Today, as soon as I be able to, I go and record a short capture, and take some photos.
I tried to isolate the red color, and then I don't know how to detect circles, because, most of that red color is from the roofs of houses...

See later.
John Christian from Norway  [25 posts] 9 years
Well, the circle detection only works on edge data so you need to run it through the Edges -> Canny filter before the Circle filter. Please post some pictures here and we can see what we have to work with.
from Australia  [87 posts] 9 years
Hej druze,

This is probably how I would approach the challenge. Road signs you are after consist of 2 parts: red circle and the inner white bit with a number.

You might be able to get 2 circles (one inside the other) from a road sign: the outer edge of the red circle and sign, and the inner boundary between red circle and white in the sign.

If this appears clear enough, use blob filter to locate blobs 'within' (or 'around') blobs. For help, look at the blob filter under documentation. This should give you a location of the speed limit number you are after.

Hope this is of help, sve najbolje.

Nemanja Sedoglavic (originalno iz Srbije)

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