使用Opencv检测文本上的角点

Question

I need a help on image processing on opencv, I have a kind of trapez to process, so I need to warp Perspective, it´s easy to do this, but I need extract source points on this image. Note, the image has only a text, on this example I draw red lines to show what I need to get. I need detect the corner points (marked with a blue point on example).

Any help?

Answer 1

You can isolate the text inside the image by executing the bounding box technique , and the corner points will be stored by the vertices variable:

cv::Point2f vertices[4];
box.points(vertices);

and you'll be able to manipulate them by accessing their X,Y coordinates:

std::cout << "Point 1: " << vertices[0].x << "," << vertices[0].y << std::endl;
std::cout << "Point 2: " << vertices[1].x << "," << vertices[1].y << std::endl;
std::cout << "Point 3: " << vertices[2].x << "," << vertices[2].y << std::endl;
std::cout << "Point 4: " << vertices[3].x << "," << vertices[3].y << std::endl;

The link I shared provides a complete implementation of this technique. It is the droid you are looking for!