1from __future__ import print_function 2from __future__ import division 3import cv2 as cv 4import numpy as np 5import argparse 6import random as rng 7 8rng.seed(12345) 9 10def thresh_callback(val): 11 threshold = val 12 13 ## [Canny] 14 # Detect edges using Canny 15 canny_output = cv.Canny(src_gray, threshold, threshold * 2) 16 ## [Canny] 17 18 ## [findContours] 19 # Find contours 20 contours, _ = cv.findContours(canny_output, cv.RETR_TREE, cv.CHAIN_APPROX_SIMPLE) 21 ## [findContours] 22 23 # Get the moments 24 mu = [None]*len(contours) 25 for i in range(len(contours)): 26 mu[i] = cv.moments(contours[i]) 27 28 # Get the mass centers 29 mc = [None]*len(contours) 30 for i in range(len(contours)): 31 # add 1e-5 to avoid division by zero 32 mc[i] = (mu[i]['m10'] / (mu[i]['m00'] + 1e-5), mu[i]['m01'] / (mu[i]['m00'] + 1e-5)) 33 34 # Draw contours 35 ## [zeroMat] 36 drawing = np.zeros((canny_output.shape[0], canny_output.shape[1], 3), dtype=np.uint8) 37 ## [zeroMat] 38 ## [forContour] 39 for i in range(len(contours)): 40 color = (rng.randint(0,256), rng.randint(0,256), rng.randint(0,256)) 41 cv.drawContours(drawing, contours, i, color, 2) 42 cv.circle(drawing, (int(mc[i][0]), int(mc[i][1])), 4, color, -1) 43 ## [forContour] 44 45 ## [showDrawings] 46 # Show in a window 47 cv.imshow('Contours', drawing) 48 ## [showDrawings] 49 50 # Calculate the area with the moments 00 and compare with the result of the OpenCV function 51 for i in range(len(contours)): 52 print(' * Contour[%d] - Area (M_00) = %.2f - Area OpenCV: %.2f - Length: %.2f' % (i, mu[i]['m00'], cv.contourArea(contours[i]), cv.arcLength(contours[i], True))) 53 54## [setup] 55# Load source image 56parser = argparse.ArgumentParser(description='Code for Image Moments tutorial.') 57parser.add_argument('--input', help='Path to input image.', default='stuff.jpg') 58args = parser.parse_args() 59 60src = cv.imread(cv.samples.findFile(args.input)) 61if src is None: 62 print('Could not open or find the image:', args.input) 63 exit(0) 64 65# Convert image to gray and blur it 66src_gray = cv.cvtColor(src, cv.COLOR_BGR2GRAY) 67src_gray = cv.blur(src_gray, (3,3)) 68## [setup] 69 70## [createWindow] 71# Create Window 72source_window = 'Source' 73cv.namedWindow(source_window) 74cv.imshow(source_window, src) 75## [createWindow] 76## [trackbar] 77max_thresh = 255 78thresh = 100 # initial threshold 79cv.createTrackbar('Canny Thresh:', source_window, thresh, max_thresh, thresh_callback) 80thresh_callback(thresh) 81## [trackbar] 82 83cv.waitKey() 84