Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
hackassin
GitHub Repository: hackassin/learnopencv
 Path: blob/master/Contour-Detection-using-OpenCV/python/contour_extraction/contour_extraction.py
3150 views
1
import cv2

2


3
"""

4
Contour detection and drawing using different extraction modes to complement 

5
the understanding of hierarchies

6
"""

7
image2 = cv2.imread('../../input/custom_colors.jpg')

8
img_gray2 = cv2.cvtColor(image2, cv2.COLOR_BGR2GRAY)

9
ret, thresh2 = cv2.threshold(img_gray2, 150, 255, cv2.THRESH_BINARY)

10


11
contours3, hierarchy3 = cv2.findContours(thresh2, cv2.RETR_LIST, 

12
                                       cv2.CHAIN_APPROX_NONE)

13
image_copy4 = image2.copy()

14
cv2.drawContours(image_copy4, contours3, -1, (0, 255, 0), 2, 

15
                 cv2.LINE_AA)

16
# see the results

17
cv2.imshow('LIST', image_copy4)

18
print(f"LIST: {hierarchy3}")

19
cv2.waitKey(0)

20
cv2.imwrite('contours_retr_list.jpg', image_copy4)

21
cv2.destroyAllWindows()

22


23
contours4, hierarchy4 = cv2.findContours(thresh2, cv2.RETR_EXTERNAL, 

24
                                       cv2.CHAIN_APPROX_NONE)

25
image_copy5 = image2.copy()

26
cv2.drawContours(image_copy5, contours4, -1, (0, 255, 0), 2, 

27
                 cv2.LINE_AA)

28
# see the results

29
cv2.imshow('EXTERNAL', image_copy5)

30
print(f"EXTERNAL: {hierarchy4}")

31
cv2.waitKey(0)

32
cv2.imwrite('contours_retr_external.jpg', image_copy5)

33
cv2.destroyAllWindows()

34


35
contours5, hierarchy5 = cv2.findContours(thresh2, cv2.RETR_CCOMP, 

36
                                       cv2.CHAIN_APPROX_NONE)

37
image_copy6 = image2.copy()

38
cv2.drawContours(image_copy6, contours5, -1, (0, 255, 0), 2, 

39
                 cv2.LINE_AA)

40
# see the results

41
cv2.imshow('CCOMP', image_copy6)

42
print(f"CCOMP: {hierarchy5}")

43
cv2.waitKey(0)

44
cv2.imwrite('contours_retr_ccomp.jpg', image_copy6)

45
cv2.destroyAllWindows()

46


47
contours6, hierarchy6 = cv2.findContours(thresh2, cv2.RETR_TREE, 

48
                                       cv2.CHAIN_APPROX_NONE)

49
image_copy7 = image2.copy()

50
cv2.drawContours(image_copy7, contours6, -1, (0, 255, 0), 2, 

51
                 cv2.LINE_AA)

52
# see the results

53
cv2.imshow('TREE', image_copy7)

54
print(f"TREE: {hierarchy6}")

55
cv2.waitKey(0)

56
cv2.imwrite('contours_retr_tree.jpg', image_copy7)

57
cv2.destroyAllWindows()

58


59