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Code from the tutorial doesn't work

asked 2019-01-08 07:33:54 -0500

updated 2019-01-08 07:36:29 -0500

berak gravatar image


import numpy as np
import cv2

im = cv2.imread('test.jpg')
imgray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
ret,thresh = cv2.threshold(imgray,127,255,0)
contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)

When executing this code, I get an error: ValueError: too many values to unpack (expected 2) .

Is there a mistake in tutorial or am I doing something wrong?

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answered 2019-01-08 09:04:18 -0500

supra56 gravatar image

ValueError: too many values to unpack (expected 2) meaning you need another varaible.

 ret, contours, hierarchy = cv2.findContours(thresh,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)
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answered 2019-01-08 07:38:19 -0500

berak gravatar image

updated 2019-01-08 07:39:49 -0500

you're using the wrong tutorial for your opencv version.for latest, have a look here , for 3.4 or older here

opencv4 does no more return the image from there, so there are only 2 return values now, while older versions had 3 return values there.

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Asked: 2019-01-08 07:33:54 -0500

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Last updated: Jan 08