Today we are gonna read a barcode (and QR code) with Python, OpenCV and the dedicated library Pyzbar. BW = poly2mask(xi,yi,m,n) computes a binary region of interest (ROI) mask, BW, of size m-by-n, from an ROI polygon with vertices at coordinates xi and yi. Add a fourth point in the middle of the polygon (how you define the "middle of a polygon" is up to you :) and connect the new point with all others. findContours(image, mode, method[, contours[, hierarchy[, offset]]]). Polygon clipping is one of those humble tasks computers do all the time. It is essential to require that the polygon have no triple of collinear vertices. In this course we'll build an app that can detect and recognize playing cards using Python and OpenCV. There is an excellent writeup in this blog and there are many implementations available (include my own in javascript which also includes the original PDF of the paper). First we import the libraries opencv and numpy, then we load the image. The above code will create "Polygon 1" as in attachment. It uses a prune-and-search technique to find the largest rectangle with two corners on the polygon and a tentative prune-and-search to find the largest rectangle with three corners on the polygon. python,polygons. OpenCV-Python is not only fast (since the background consists of code written in C/C++) but is also easy to code and deploy(due to the Python wrapper in foreground). cxcore - Data structures and linear algebra support. VideoCapture(0) cv2. OpenCV doesn't have any functions to do it for you, but you can find the angle (in degrees) of each line by using: double angle = atan2(y2 - y1, x2 - x1) * 180. (Do the same for your source image) Now your task is to only map each triangle in your source image to the corresponding triangle in the polygon. It is being used by our team to annotate million of objects with different properties. py Add polygon. Using the variables we defined above, you can find the centroid by: (meanx, meany) = pts. Drawing Histograms in OpenCV. Let the convex polygon have counterclockwise-ordered vertices V i for 0 i