OpenCV C ++从二进制映像中提取功能

Question

I have written an algorithm to process a camera capture and extract a binary image of two features I'm interested in. I'm trying to find the best (fastest) way of detecting when the two features intersect and where the lowest (y coordinate is greatest) point is (this will be the intersection).

I do not want to use a findContours() based method as this is too slow and, in my opinion, unnecessary. I also think blob detection libraries are too bloated for this.

I have two sample images (sorry for low quality):

(not touching: http://i.imgur.com/7bQ9qMo.jpg ) (touching: http://i.imgur.com/tuSmKw7.jpg )

Due to the way these images are created, there is often noise in the top right corner which looks like pixelated lines but methods such as dilation and erosion lose resolution around the features I'm trying to find.

My initial thought would be to use direct pixel access to form a width filter and a height filter. The lowest point in the image is therefore the intersection.

I have no idea how to detect when they touch... logically I can see that a triangle is formed when they intersect and otherwise there is no enclosed black area. Can I fill the image starting from the corner with say, red, and then calculate how much of the image is still black?

Does anyone have any suggestions?

Thanks

Answer 1

Your suggestion is a way more slow than finding contours. For binary images, finding contour is very easy and quick because you just need to find a black pixel followed by a white pixel or vice versa.

Anyway, if you don't want to use it, you can use the vertical projection or vertical profile you will see it the objects intersect or not.

For example, in the following image check the the letter "n" which is little similar to non-intersecting object, and the letter "o" which is similar to intersecting objects :

By analyzing the histograms you can recognize which one is intersecting or not.