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Error while working with contours

when running this code `import numpy as np import cv2

image=cv2.imread('screenshoot10.jpg') cv2.imshow('input image', image)

gray=cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)

edged=cv2.Canny(gray,30,200) cv2.imshow('canny edges',edged)

_, contours = cv2.findContours(edged,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_NONE) cv2.imshow('canny edges after contouring', edged)

print(contours) print('Numbers of contours found=' + str(len(contours)))

cv2.drawContours(image,contours,-1,(0,255,0),3) cv2.imshow('contours',image) cv2.waitKey(0) cv2.destroyAllWindows()`

getting an error

OpenCV(4.1.1) C:\projects\opencv-python\opencv\modules\imgproc\src\drawing.cpp:2509: error: (-215:Assertion failed) npoints > 0 in function 'cv::drawContours'

what am I doing wrong?

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updated 2019-10-08 06:25:40 -0500

berak gravatar image

Error while working with contours

when running this code `import code

import numpy as np
import cv2

cv2

image=cv2.imread('screenshoot10.jpg') cv2.imshow('input image', image)

image) gray=cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)

gray=cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)

edged=cv2.Canny(gray,30,200) cv2.imshow('canny edges',edged)

edges',edged)

_, contours = cv2.findContours(edged,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_NONE) cv2.imshow('canny edges after contouring', edged)

edged)

print(contours) print('Numbers of contours found=' + str(len(contours)))

str(len(contours)))

cv2.drawContours(image,contours,-1,(0,255,0),3) cv2.imshow('contours',image) cv2.waitKey(0) cv2.destroyAllWindows()`

cv2.destroyAllWindows()

getting an error

OpenCV(4.1.1) C:\projects\opencv-python\opencv\modules\imgproc\src\drawing.cpp:2509: error: (-215:Assertion failed) npoints > 0 in function 'cv::drawContours'

'cv::drawContours'

what am I doing wrong?