Code for How to Detect Contours in Images using OpenCV in Python Tutorial

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contour_detector.py

import cv2 import matplotlib.pyplot as plt # read the image image = cv2.imread("thumbs_up_down.jpg") # convert to RGB image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB) # convert to grayscale gray = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY) # create a binary thresholded image _, binary = cv2.threshold(gray, 225, 255, cv2.THRESH_BINARY_INV) # show it plt.imshow(binary, cmap="gray") plt.show() # find the contours from the thresholded image contours, hierarchy = cv2.findContours(binary, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE) # draw all contours image = cv2.drawContours(image, contours, -1, (0, 255, 0), 2) # show the image with the drawn contours plt.imshow(image) plt.show()

live-contour-detector.py

import cv2 cap = cv2.VideoCapture(0) while True: _, frame = cap.read() # convert to grayscale gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # create a binary thresholded image _, binary = cv2.threshold(gray, 255 // 2, 255, cv2.THRESH_BINARY_INV) # find the contours from the thresholded image contours, hierarchy = cv2.findContours(binary, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE) # draw all contours image = cv2.drawContours(frame, contours, -1, (0, 255, 0), 2) # show the images cv2.imshow("gray", gray) cv2.imshow("image", image) cv2.imshow("binary", binary) if cv2.waitKey(1) == ord("q"): break cap.release() cv2.destroyAllWindows()